October 24, 2023
Faculty of Agricultural and Food Sciences Seminar Series and
DEPARTMENT OF PLANT SCIENCE present
DR. VICTOR M. BENDELOW MEMORIAL LECTURESHIP
HOW NATIVE PLANTS MANAGE COMPLICATED ECOLOGICAL INTERACTIONS
Presented by
DR. IAN THOMAS BALDWIN
Founding Director, Max Planck Institute for Chemical Ecology, Department of Molecular Ecology, Jena, Germany
Thanks to the long-term patient funding of the Max Planck Society, we have developed a fire-chasing native tobacco plant, Nicotiana attenuata, which grows in the Great Basin Desert, into a model for the study of plant-ecological interactions, particularly those biotic interactions that dominate the primordial agricultural niche. By training students in the lost art of natural history discovery, we have used the plant’s natural history interactions to phenotype transformed and recombinant inbred lines (RILs) of this plant, at two nature preserves in the plant’s native habitats, to understand the function of genes required for survival in nature. For the past two decades, the research program has used a reverse genetics approach following an ‘ask the plant’ paradigm to select genes for silencing experiments and field work. This talk will describe how the Department in its final stage of research, is using unbiased forward genetics wedded with unbiased metabolomics and unbiased natural history-based field biology with sentinel insects, microbes and metabolites to understand the genetics behind the management of complex ecological interactions. The Department’s recent advances in understanding the biosynthesis and function of a family of potent defense metabolites that occur in starch-like quantities in the leaves of the plant, namely the 17-hydroxygeranyllinalool diterpene glycosides (17-HGL-DTGs) and an entirely new sector of specialized metabolism that mediates non-host resistance will illustrate the approach. The over-arching approach of the Department’s work is to understand whole-plant function by combining the skills of ecologists, molecular biologists, chemists and most recently, synthetic biologists.
Well good afternoon everybody it’s a real pleasure to see you all here as part of our bendalo lecture Series in the department of PL science we have an esteemed guest here who’s going to give us a lecture today and I’m here to introduce him my name is nazam chich I’m the associate
Dean research for the faculty of Agriculture and food sciences and the host of our seminar series and uh our conversation series it’s a real pleasure to welcome Dr Ian Baldwin uh to this lecture series uh Dr Balwin is a professor and founder and director of the max plank Institute for chemical
Ecology where he studies let me get this right the nikana atenu as a model organism to understand how plants solve ecological problems Dr Balwin received his bachelor’s degree in chemistry and bi ology from Dartmouth College in 1981 and started his Graduate Studies at Cornell University where he joined the section of neurobiology and
Behavior after graduating in 1989 he became a professor in the department of biology at State University of New York Buffalo he foresaw the importance of combining multiple disciplines to study planned ecology and in 1996 he co-founded the max plank Institute for chemical e ology a multi-disciplinary center to study the chemically mediated
Interaction of plants for a scientific contributions he was elected a member of the National Academy of Sciences in 2013 and a fellow of the American Association for the advancement of Science in 2016 so without further Ado please help me welcome Dr Ian Baldwin thank you to
It’s a real pleasure being here it’s a real pleasure being amongst colleagues who work on something real and important um and I want to contrast that with the sort of things that we do in the MP society which is entirely pure research we have no requirements for application um and
Therefore we can go on to tangents that seem perhaps frivolous to those um um yeah perhaps frivolous we just leave it at that um I’m going to give you a a fairly High Velocity talk if I can uh overcome that beautiful lunch that I had and uh cover
A number of things that we’ve been discovering with this particular plant which I’ll introduce in a moment this n kosana tenu and thank you for that completely correct interpret pronunciation of that of that genus and species it’s a native tobacco PL plant of the Great Basin Desert and as you can
See there are many co-authors on this talk um whose names I uh will only have a chance to um comment on as we go through the slides um uh I understand there will be a breakout meeting tomorrow uh for three hours so I’m hoping that if I move too fast through
Some of these topics we’ll be able to unpack some of them during tomorrow’s uh discussion so if you are interested in some details or confused about something please uh don’t hesitate to join that um okay so what I need to say something a little bit about the Institute so the
Mo Institute for chemical ecology is one of the 85 M plun institutes um throughout Germany and I got a chance to found one in the former East to help sort of redress the scientific imbalance that occurred after the Venda after the rejoining of East and West Germany um
This institute um as Z pointed out is started in 1996 um we built this building and moved into it in 2002 and our main goal really was to at least in my department was to U convert chem IAL ecologist into a species of scientist that I like to call
The genome enable field biologist and what I mean by that and here I have the sorial representations of these different disciplines um chemical ecology is a is a mashup of ecology and chemists right so here we have you know the classical chemist and the classical ecologists with their beon stocks um
That’s actually Fritz Muer who um who coined malarian mimy and among other classical ecological phenomena um but with the ability of molecular biology to manipul to manipulate the chemistry uh by manipulating the genes responsible for the chemistry that plants and insects use to interact in in nature and
We of course wanted to bring molecular biologists on board um this of course was before the first plant genomes were sequenced um so we had to do a number of a bit of thinking about what we wanted to um study in terms of model systems and develop for this system and the one
Thing nice about the MOX Society is that we’re given long-term patient funding so we’re able to really lay out a 20-year plan and I’m going to sort of give you a a perspective on uh what we managed to do um in that 20-year period um I want
To talk a little bit about the type of science we do because as you know science can ask questions at many different levels of analysis and in very general terms there are the how questions and the why questions and 99% of all scientists ask how questions how
Do things work what are the mechanisms that are involved but a certain fraction of them ask questions that that are really of the why sort um what are the uh evolutionary consequences of a particular trait how does the trait influence an organisms arwi and fitness and if you’re interested in genomics um
Just about every Gene that isn’t pseudogenized in a genome has some influence on organisms uh darwinian Fitness it helps to move that organism’s genome forward in time helps to produce successful grandchildren which is what darwinian Fitness is really all about um and chemical ecologists have always straddled that line because um by
Synthesizing and and purifying the chemistry that is involved in ecological interactions they’re able to manipulate them independently of the organisms that are involved and of course when you bring molecular biology into the B you can do that via the organism and so what we do in this department really is to
Understand not mechanism for the sake of mechanism but mechan M for the sake of understanding function and so what we do is we typically delve deep enough into the mechanism of something so that we can generate a genetic manipulation and then ask the question of what are the functional consequences what are the
Consequences for the organisms Darwin and fitness of doing that and in doing so we can answer why questions why do organisms have particular traits so I wanted to say something about the plant that we chose um and this is a plant that I’ve been working on since my graduate days Cornell
It’s a native tobacco plant um and it has the characteristic of chasing fires in ecological time so it hangs out in the seed bank for 400 years between fires and then it responds to factors in wood smoke um and then germinates and grows it’s an annual plant for a short
Period of time utilizes that postfire environment um and then goes back into the seed bank waiting for the next fire to come along and as a consequence it grows in that very Niche that we grow most of our agricultural plants the uh slash and burn agriculture was the foundation of Agriculture and uh
This is a plant that has been growing in that Niche for four million years or so and so the whole idea was to understand what sort of traits this plant had evolved to be able to fit into that Niche so that hopefully would’ be able to make our crop plants ecologically
More sophisticated requiring fewer inputs fewer things that end up damaging the environment um and perhaps you know be able to regulate their their activities more um um with less pampering so this whole business of chasing fires really all has to do with perceiving chemistry in the environment
So the plant um sniffs out the various tpes that the dominant vegetation produces and then maintains its stormy as a consequence of sniffing those particular Turpin we don’t know anything about the mechanisms of that sniffing process but after a fire and those turpins are pyrolized and removed there
Are factors in wood smoke that includes the itins but a bunch of other factors that are smoke compounds phenolic or engine that activate um keratin signaling and stimulate jabber and biosynthesis and activates germination so that’s what that’s how this plant synchronizes its germination after fires that’s how it chases fires and the main
Question we wanted to really ask here was uh why do these plants make so many interesting secondary metabolites what are all these different types of specialized chemistry uh doing in a plant what are they doing with that chemistry um this is a plan as I as I mentioned um
That it typically solves its problems uh through this chemistry plants can’t move around so they use their chemistry to manipulate all the organisms that they interact with and they use their chemistry for that um but little was understood and on how they do that and
This is what we wanted to explore in the system nly the whole process of solving ecological problems now I’m going to talk heavily about a particular signaling Cascade that activates a large fraction many SE of this particular secondary metabolites um and it’s called the jasm signaling pathway and it’s a
Pathway that many of you are familiar with but with the the homologous Series in animals namly the prostagladin the prostagladin start out with the 20 carbon four double bonded arachadonic acid which goes through a series of chemical reactions to make this thing called prostagladin that activates when
You are wounded and you have infection and and it stimulates pain well there’s an exactly similar sort of pathway in PL it starts out with the 18 carbon three double bonded linolenic acid which is then goes through a number of steps to make this compound called jasmonic acid
Which is then activated by a conjugation with an amino acid and then this forms the signal molecule which then activates a whole series of of secondary metabolite Productions um and is part of this environmentally sensitive system so I’m going to talk a good bit about that now our main question really was to
Ask how does nuosen to solve its problems with its chemistry U Better Living Through Chemistry and chemistry is really the only way that that plants can solve problems um um and I will give you some examples of that and we wanted to develop platforms metabolomics and ecological phenotyping and genetic
Platforms that were unbiased to be able to ask these questions from an unbiased perspective not so that we were anthropomorphizing this plant but really phytomorphology was doing um now the unbiased chemistry was fairly easy to do because during this 20-year period thanks to Moore’s Law Mass spectrometers got faster and
Faster and able to capture a much larger fraction of the metabolites coming out it and I’ve always been interested in Mass spectrometry so we’ve bought just about every type of mass spectrometer possible and utilize that to characterize the the metabol of plants and the beginning it was mostly very targeted spectrometry going after
Particular metabolites but then it developed uh uh when we got used to being able to massage the enormous amounts of data that each one of these runs would generate be able to do unbiased untargeted metabolomics on on these plants and and it’s really thanks to a number of really key people in the
Group Manuel gagal and dang Lee who who developed a lot of the infrastructure for that unbiased metabolomics um Manuel is now a professor at Strasburg and dang Lee is a group leader in um Shanghai um the uh unbiased ecological phenotyping was a little bit more challenging because it involved building
An 8,000 kilometer Corridor between the institute in Germany and the field sites where we were allowed to do transcending plant releases which were the Native habitats where this plant grows and we were very fortunate to develop um a number of good relations with both the University of Arizona and with bringham
Young University um who have a couple of nature preserves that we were able to do transgenic plant releases in and we’ve been doing that for the past 25 years um we were fortunate to have the um David attenborough’s BBC film team out um a couple years ago and uh we got some
Footage here to give you some ideas about what this field site looks like um if you have seen uh the Green Planet which just came out this spring um we have about 15 minutes in episode four of the Green Planet um if you and then you
I’ll show a couple more clips from this uh uh this movie thing and you can get all the sort of the music and all the other Attenborough uh additives to this uh to this Clips but if you fly to Las Vegas which is our nearest site um our
Nearest airport and you look out the window on the right hand side and look down you can see our Field Station basically it’s located down in this particular Cannon um to the to the uh West we have area 54 um and to the east is a whole series of polygamous uh
Communities um so it’s very isolated we don’t have a lot of neighbors um uh the nearest uh paved road is 70 Mi away um and we have a couple field sites down there where we have some irrigation where we do the planting and of course we use natural populations when the
Fires allow us to do so um and the Regulatory Agencies allow us to do releases there for particular questions and sometimes we have to manipulate pollinators like with these Klux Clan hats that we put on plants sometimes but the basic procedure procedure that we do is to allow the organisms that phenotype
Plants better than we do to do the phenotyping for us because every time we generate a transgenic plant that is knocked out in a particular pathway or a particular signaling system they typically don’t have a phenotype in the glass house they don’t look any different from a normal wild type plant
But once you put them out into nature and you allow the organisms that interact with this plant on a regular basis they show up a phenotype for us so what we basically done is try to train our students to do old-fashioned Natural History look at the organisms that
Actually study this plant carefully and do a better job of it so we’re basically using nature here as a laboratory for studying Gene function um and um and I’ll will tell you a number of examples of this and I’ll start with some obvious ones and then move more uh into some
Things that are perhaps less obvious um it is a tobacco plant after all and it is a plant that um the five Native American tribes who have Incorporated this plant into their ceremonies and buried their dead with seeds of it have used it because it produces absolutely God’s amounts of
Nicotine um and uh one single leaf will when it’s fully induced will have the same amount of nicotine as an entire carton of gulis cigarettes um and uh so you just have to take one good hit and you be communing with your ancestors um and nicotine obviously is is an
Absolutely perfect anti- herbivore defense compound it’s a defense compound because plants don’t have nervous systems so they don’t get poisoned by it but it poisons the neuromuscular Junction so any organism that has a muscle chews moves is going to be poisoned by this and um and if you knock
Out nicotine production by silencing one key Gene Puttin methyl transferases that I’ve got an x on the top of it you can knock down nicotine production and when you put those plants out into the field the deer the mule deer that are in the neighborhood immediately find it Gophers
Dig holes over to it and and pull it down into their nests rabbits chew off the outer bark of it and and strip it so you get an immediate response from the melean herbalore community um that tells you just how important that metabolite is for the daily existence of these
Plants but as in all cases in nature there are of course insects out there that have really figured out how to break through nicotine and are completely nicotine tolerant and this is one of them this is manduka sexa manduka qu Immaculata has the world record for nicotine tolerance um and even uses
Nicotine for its own defense something that we we discovered and what we were interested in was how does the plant deal with this particular insect that has broken through this fantastic defense barrier so it’s exactly a crop plant situation you transform your crop plant with a wonderful anti herbivore
Compound you know you know and after a few years you’ve evolved resistance in your in your favorite Pest and so what does the plant what does a native plant do when that happens when it when somebody breaks through it well the whole story starts up with this little
Bit of slimy stuff on the cut edge of the leaf there that the caterpillar was chewing um that’s caterpillar spit um and in caterpillar spit are a series of molecules called fatty acid amino acid conjugates and these are the herbivore activated elicitors these are the on that tell the plant that it’s being
Attacked by manduca sexa and not any other of about 30 other LEP adopter species that will attack it and then the plant begins to respond accordingly and what I want to do in the next few minutes here is tell you about what does the plant do when it knows it’s being
Tact that the wound that is that is happening on this particular Leaf is coming from this particular herbivore and what does it do and it does some remarkable things it basically activates a signaling Cascade in which the central component of that signaling Cascade is the jasm signaling part of it so these
FACS at the top there are preceded by a receptor which we still have not yet identified activates this beautiful kyes Cascade and then it pumps right into Jasmin siging through the plastid and generates the jasic and acid which I showed you the structure of conjugated to isoline um to form this J isoline
Which is then um perceived by a a protein sandwich between one of 12 Jazz proteins and a koi protein which then transduces the signaling into the all the beautiful chemistry that the plant will make of course as we talked yesterday there’s an awful lot of cross talk between other phyto hormones and
There’s a bunch of other things that are also piece other phyo hormone signaling that’s also perceived by those FACS ethylene Calene salic Cene and the like and these are all part of making sure that the plant doesn’t get faked out by other signals that are in caterpillar
Spit caterpillars after all do not brush their mandibles before they eat a leaf and therefore there is a lot of microbes and those microbes are introduced into wounds as they chew and you don’t want the plant to be activating the salicylic acid anti-pathogen response which would then thwart the jmate U mediate defense
Signaling that the that the plants producing so there’s there’s some tuning through phyto hormonal cross talk um in this process um and there’s a beautiful receptor called learc that that mediates that okay so what does all this siging do um it B basically revamps the plant’s defense avoidance and tolerance
Responses and I’m going to very quickly run through those examples of those three types of responses these are all things that are activated denovo by caterpillar feeding when those FC’s are introduced so as I go through this you just have to remember that all of this doesn’t happen in the plant until those
FACS are introduced into wounds and then transduces this particular signaling and the first thing I want to do is to talk about the tolerance responses um I consider this sort of the mahat man Gandhi approach toward dealing with your your oppressors that you figure out a
Way to tolerate it and then rebound and go on uh with your life um and this was actually discovered through a very pure Natural History observation I spent a lot of time walking through Fields after lightning strikes and fires and you see these natural populations Bloom and I’ve
Noticed that the plants that are heavily chewed on by caterpillars like this plant here that’s being attacked by two full manduka larvi they’re both in the third fourth insar it’s going to be stripped fairly thoroughly those plants at the end of the season when it dries
Down start to reflower if we get a little August rain and they clearly have some extra reserves because none of the other plants reflower it’s only those plants that have been heavily stripped reflower during that time and we were able to pin it down uh using some very
Nice C11 uh technology from o syron and in ulik Germany um to be able to trace how carbon moves through a plant after a plant has been elicited by fac sine so we simply elicit a plant with f siging use C11 CO2 and then look where it goes
And it turns out instead of going up to young leaves which is the normal thing that a plant does you know it fixes carbon and makes new leaves transporting that photo simulate to grow new leaves it pumps that fixed carbon down to the roots and it keeps it in The Roots until
The caterpillars are going so so basically and this all works through a particular snark kinas there’s a beta subunit to the snark kinas which is non regulated it’s actually responsible for that we were able to transform plants down regulate that snur kinas and get plants with the exact same pattern of
Carbon transport down to the roots um as if they were elicited by these caterpillar bit factors and the biological significance of this bunkering of carbon done into the roots is that caterpillars have two stages in their lives they have the eating machine stage when they’re consuming Leaf
Material and then they uh pupate and turn into a sex machine where they’re basically having sex and laying eggs and that’s it in terms of uh of their damage to the plant and during that time when the caterpillar is in the eating machine stage of its life it’s bunkering carbon
Down to the roots and then it waits for the caterpillars to go into their sex machine stage fly off um and then the plant ref flowers and it ref flowers much more effectively thanks to this bunkering response so that’s really the tolerance mechanism the physiology of their tolerance to this particular
Herbivore and that’s elicited by FC cing okay so that’s the tolerance component of it um they also activate an avoidance response and you may be wondering you know how does a plant avoid um being attacked by a caterpillar because plants don’t tend to run away the way that most animals have avoidance
Responses um but in order to understand this you need to understand um where the caterpillar comes from the caterpillar is clearly the bad guy in this particular interaction but it is produced by a good guy the mom of this caterpillar the ovap positing female is the main pollinator of this plant um and
This particular uh um female The Moth of this has this unusual behavior that after it pollinates the flowers this normally occurs in the the nighttime you see it ositive it bends its abdomen curls and lays and egg so it nectar and over posits nectar and over posits so
Every time it Prides a bit of pollination surfaces it leaves a bit of bad news for the plant the bad news that grows into this voracious you know caterpillar that eats plants and is completely resistant to nicotine and the flower on the the main type of flower this plant produces is
Completely adapted to this particular moth you might have noticed it has a very long gay a very long prascus um in order for the flower to be pollinated and for the moth to to nectar on those flowers it actually has to stick this very long Galia that it unrolls as it
Flies along into the bottom of the flower and Po in so to do that the flower has to be in an upright position and you might have noticed that during that time series through the night the flower waves and moves up into this up position and then it goes back down
Again during the day that waving is absolutely essential for allowing the mechanics of the moth to be able to get its boscus in but there’s another thing that occurs during the W response the Corolla opens up and during the opening up of that Corolla the flower starts emitting this beautiful scent that’s
Made of a structure called benzil acetone the whole waving response happens in the peduncle which is this little connection piece between the flower and the stem and the peduncle if you chop it off Waves by itself it waves automatically in the Peter dish and when you have this system you can figure out
How the waving system works it turns out it’s driven by components of the plant circadian clock um and that part of the circadian clock causes a a redistribution of oxen across the ab and axial sides of it so it’s really a growth response the the PED peduncle is
Growing differentially um and it’s very much like the nicating behavior that Darwin described in his notebooks if you’ve ever had a chance to read them um uh so this wave in response is important um and the chemistry of the Rel so that floral scent is super important for this
Moth to find this plant now um The Moth uses the chemistry which we’ve been able to knock out by figuring out the biosynthetic pathway we call it chakon synthes but it actually turns out to be a polyte in they so more correctly named uh recently we have an RNA construct
We’ve been able to to knock that down with and produce flowers that do not make this scent at all um and when that happens The Moth can’t pollinate they can’t actually find it but this whole coordination of chemistry and waving is a little bit like Dirty Dancing the
Flower has to kind of get into the right position release the right thing otherwise the pollination doesn’t occur so this is a flower that is very specific for this particular moth um and when you have a lot of aiver when this caterpillar chews away on the plant and
Begins to damage it and is not taken out by a lot of the defenses that I’ll be talking about a little bit later and you get a lot of uh fac based signaling the plant does some very interesting things it produces a different type of flower
But I want to I want to just show you the importance of this this this uh benzil acetone emission because if you knock it out the MS can’t find the flowers can’t find the plants um if you have night vision photography you can be able to see the malls flying by these
Plants that are not emitting and it go directly to those plants that are emitting and it also turns out we have a couple papers on this too that the tip of the proboscis has sensors for this benzil acetone and they use the the proboscis basically to taste their way
Into the center of the flower so the the floral scent is important for longdistance attraction of the moth as well as the short distant orientation of the proboscis into the moth so they basically can’t do any pollination without of them now if I say the plant are being attacked by lots of
Caterpillars and the defenses aren’t working the plant makes a new type of flower this new type of flower does not open up on that first night that’s called the night open flower is the one that opens up and the morning open flower as you can see in the top bar
There is the one that doesn’t open remains shut does not wave and does not scent and this flower um uh and that whole process is all mediated by fac mediated jasm siging it turns out the mechanisms all involve um a hijacking of the the clock that mechanism that causes
The waving by jasm signaling there are seven of the 14 Jazz proteins that interact directly with ztl portion of the clock and that prevents this whole waveing response from from occurring and so at the end when the morning comes around the flowers that are the morning open flowers have their flued are still
Closed have not released any floral scent they’re full of nectar because they haven’t been visited by Ms the night before and they haven’t waved and the nice thing about these flowers is that they are pollinated by a bird a hummingbird that does not lay caterpillar eggs so it it gets
Pollination services without having to have the the deleterious consequences of having caterpillar eggs being laid on it so this is one of the this is an avoidance response it’s avoiding the whole problem of having caterpillars by switching to a different type of sexual system now you might be asking yourself
Why doesn’t to do this all the time you know why don’t you just stay with the hummingbird Well turns out the hummingbird is a lousy pollinator it’s a trap liner during this time it’s got a nest right over here it comes through and just goes and moves pollen within the plant
Causing self-pollination the hawk moth on the other hand is flying from 500 kilometers away from the last burn bringing in a much more Rich pollen source and The Offspring that are sired in those pollinations by the by the hawk moth have many more paternal genotypes
In there and if you are a seed that’s got to live in the seed bank for 400 years it’s a very good idea to have a lot of genetic diversity so that’s that’s sort of the basic reason for for why you want to stick with the moth um
As long as the moth isn’t doing too much damage and you can then avoid it if you have to um and go to a to a hawk MTH so that’s that’s avoidance by chaining pollinators and you know in all this plants have remarkably fluid sexual systems and this is just one of those
Beautiful examples about how how you can simply um solve a major ecological Problem by by changing your sexual orientation now the the main part of our our research has been really the bread and butter has been defense responses and the types of interesting chemistry that’s involved in the defense responses
And I want to first talk about the indirect defense responses that plants use and these are mainly the the volatiles that plants produce the things that are emitted from the plant after fac siging activates the plant and the way it works is that when a cater CH on
Leaf whether it be over here or there the plant gets these signals that come into it and activate the production of a group of uh Cisco Turpin there’s a beautiful bouquet of volatiles that the whole plant begins to emit from it’s like a Chanel number five in fact it
Chanel Number Five has 149 different structures in it um the volatile bouquet that’s induced by caterpillar ATT has 122 different structures in it there’s a couple key components that if you knock them out you can take out this whole signaling component the main one is this transal bergamin that I have pictured up
Here in red and transal burine uh is a compound that attracts a beautiful little Predator called geoc corus Palin that lives in the soil nearby many meters away and when it sniffs transa berine it comes running over to the plant and looking for the caterpillar but it needs more information because
The the the Predators are small the caterpillars are small the plants can be big um and you need some local guidance as to where the caterpillar is located um and that’s provided by the actual wounding of the of the leaf by the cat’s mandibles and that gives off a green
Leafy of volatile a glv a six carbon molecule uh which is then isomerized by the caterpillar spit to an even more active six carbon structure which attracts now I need to talk a little bit about the chemistry here because I’m going to return um uh to this in a in a
Moment so I told you that Jasmine signaling involves the taking of this 18 carbon 3 whoops double bonded uh um fatty acid um to make jasmonic acid and that’s uh mediated by a leox jates called uh locks 3 um in a rabid opsis there’s only one locks but in in
The kosana there’s two Lockes that do this job one of them makes a jesmin the other one does functions as the lias cleaving the hydrop peroxide the 13 carbon 13 hydrop peroxide into a C6 and a C12 the C6 forms this Z3 hexl which is a glv green leafy volatile which is
Attractive to the to the predator and provides the local information but the caterpillar spit isomerizes that to make an even more active zet2 hexanal which is really important really easily perceived by these predators and then they come right over and uh attack the uh attack the caterpillar so we we
Published this uh in science it seems like an interesting observation that the that the caterpillar spit would basically call a much more effective predator s to itself um and I’ll return to that inference in a moment but here’s David aten’s view on this they took him
3 weeks to get this particular shot the you see the little Predator being attracted by the Vol coming up to a caterpillar stabbing it sucking it out it’s a perfect way to deal with your herb Wars you don’t have to poison them you just put out information it’s like
Calling the police and they come in they feed much more effectively they clean that your caterpillar um uh it’s a indirect defenses really work it’s really impressive um there are a number of different Predators uh that are on the plant that are attracted by those
Volatiles um I won’t go into all of them but I want to talk about a group of predators that are recruited from the ground and it’s a different type of chemistry that recruits those Predators from the ground this is also a type of indirect defense and this is a a defense
Called asil sugars that are produced in tricomes tricomes are the little hairs on leaves that sometimes make the leaf sticky and they can actually form a sort of a a a a a fly track WRA type of thing you see insects being stuck on plants on there but these little tricomes exude a
Sugary stuff from the top of it if they’re secretory and they um consist of a a sugar molecule aerified with little fatty acids on the end of the hydroxy groups of the sugar um those hydroxy groups when the when the sugar droplets are ingested are cleaved and they release those fatty
Acids giving the caterpillar a body odor of those fatty acids and these are very volatile fatty acids these are the the scent of baby barf if you have a baby you’ll frequently be smelling of this as it barfs on your shoulder and you burp them um but these are the sort of the
The you know not so noxious but quite you know all Factory active short chain fatty acids that are that are released um caterpillars when they first hatch they feed on these tricomes the tricomes basically are their first meal so when they ingest those those asil sugars the
Very high midgut pH of the caterpillar’s midgut esterifies those fatty acids from the sugar molecules and the caterpillar starts getting this body odor but not only does the caterpillar get a body odor but the caterpillar’s poop gets a body odor so when the caterpillar poops here’s a pooping caterpillar you might
See that little pop falls to the ground that nice rolent smelly frass Falls onto a hot ground this is Utah after all the ground is 50 60° Celsius um and it volatilizes off and when you have a lizard Trucking along on the ground or an ant Trucking along the ground they
Perceive those volatile fatty acids and believe it or not ants think in three dimensions they look up and they look for a a caterpillar up on the plant lizards do the same thing and so you see you can do these experiments with oven dried frass that doesn’t smell or a
Fresh FL that does smell put in the bottom of a stick and lizards will run up the stick with a fresh frass at the bottom you can uh purify or synthesize the fatty acids and make your own little spray um sort of as a you know perfume
It’s going to be available in the duty-free shops any moment now um spray it at the bottom of the of the stick and you can get ants to run up the stick um looking for for caterpillars um and there they are charging up there so basically what happens is that this
First meal this lollipop that is served up on these little tricomes for caterpillars is actually an evil lollipop because it tags them for predation um so this is an example another example of the type of chem indry that recruits uh higher trophic levels and it functions as an indirect
Defense um so those are that’s part of the chemistry that’s involved in indirect defense the plants make all these other compounds that are really direct defenses and I’m going to just give you examples of a couple of them um and I you know I have to be careful here
Because I can really bog down in the in the in the chemistry of it I I know when people’s eyes start glazing over but um let me just tell you about some of them the these were some um compounds called HG DTG thuring glycosides and they if
You do a normal MPC lcms they sort of occupy a middle portion of this catogram there’s about 46 structures here we were only we only had to characterize four of them uh by plastical NMR threedimensional characterization the rest of them we could do by insource fragmentation from from Mass
Spectrometry um they are a dipine backbone with a bunch of double Bonds in them functionalized on either end of that Di turpine and then aerified with a bunch of sugars glucose or or um rabinos and then malate and that’s what generated the 14 different structures now what is typical of secondary
Metabolism is that there’s been a number of Gene duplication events that allow for particular sectors of metabolism to be to evolve and neof functionalize and as with uh um the GPS’s that produce gibberellin that produce carotenoids there’s been a d duplication event and another G ggps is specialized for
Producing these thuring glycosides so all you have to do is generate an rni construct to knock out that particular ggps and you can take the whole metabolic sector out and when you do that and you feed caterpillars on them you can see how fast they grow they basically quadruple growth rate if
They’re not eating plants with these dibine glycosides in them and if I showed you the plant you wouldn’t be able to tell the difference they look completely normal put them out there and the caterpillars love them they grow enormous and they grow much faster so this is an example where the chemistry
Of the these direct defenses is really all a matter of slowing the caterpillar’s growth down and it also turns out when we figured out the biosynthetic pathway of what happens to that particular dipine as it leaves the plastid and has been functionalized on the both ends and gets decorated by
These sugar molecules we figured out why it’s toxic and it turns out that if the architecture of the pathway itself is what allows the plant to solve the chemical waste thump problem of chemical defense the more potent a chemical defense is the more poisonous it is the
More problematic is going to be to make and store and the way the plant solves it is to produce a biosynthetic pathway that keeps a certain reaction from happening and it turns out decorating the molecule with particular sugars and particular places is exactly how it’s
Done if you take those sugars off or you don’t allow the plant to make those particular sugar dises the plant immediately starts showing toxic symptoms and dying um and the exact same thing happens in the caterpillar’s midgut the caterpillar ingests these dipin with the sugar things it starts
Pulling those sugars off because it likes to digest sugars and then it immediately starts to cause the the DI turpine to be hydroxy in a number of different places and that kills a central component in spinder lipid biosynthesis which is toxic for for the plant and for the caterpillar so we
Unraveled and this was published in science last year um uh the toxic mechanism by simply working out the biosynthetic pathway is another one of those beautiful examples where mechanism and function really come together very nicely okay so what I was saying is that a lot of these direct defenses function
To slow down caterpillar growth and one of the classic types of molecules are these protas Inhibitors that plants produce and the more protas inhibitor a plant produces the less effective the cat’s digestive system is the more it has to eat the slower it grows and when you keep the caterpillar small and slow
It down by having to make it deal with all these toxins you end up making it much more vulnerable to the Predators so let me just show you an a visual example of this here’s Mary Schuman a former postto in the root pretending to be a predator poking a caterpillar who’s
Feeding on a normal wild type plant replete with all those defenses and you can see the caterpillar is barely doing anything it’s getting poked it’s just sort of you know leaveing me Al alone uh she’s picking it up on the tail it doesn’t wiggle it hangs there limp and
Flaccid it’s sort of a pathetic cat caterpillar contrast that with a caterpillar feeding on a defenseless plant I’ll show you in a moment how we make that defenseless plant and you see a much more pugilistic caterpillar a caterpillar that’s able to fight back turn around spit at the at the at the
Predatorial forceps um and uh and defend itself so this just shows you how effective this combination of both direct and indirect defenses are when you have a third trophic level component it and this is something we do not do very well in agriculture we do not really bring natural enemies in as
Effectively as we could and so much of it is simply just a matter of providing information to those predators to let them know where the caterpillars are where they’re feeding what they’re doing um and that’s I think something we can do much more effectively um uh the the last story is
A little bit longer one and and it involves um some brand new chem mystery that we just published in science last year uh that solves a 20-year puzzle that we had um and I like to describe very briefly this 20-year puzzle that we had it involves a combination of both
Direct chemistry and indirect chemistry the indirect chemistry were the glvs that I already introduced and the direct chemistry were a group of compounds called phenolamides which are basically phenolic compounds with an amine of a pucine um Arginine attached to them um and we knew they we knew about their
Defensive function already but this combination was something that was involved in nonhost resistance and I think we found one of the first examples of nonhost resistance for an insect um particularly from a natural system so 20 some years ago U we released the group of uh jasm deficient plants who were
Knocked out in locks 3 remember I told you locks 3 was the beginning of the Jas signaling pathway so it it was deficient in Jas signaling we put these plants out into nature in the in the nature reserve and they were attacked of course by all the herbivores that we knew were
Herbivores on a tenada but they were also attacked by a group of herbs that we had never seen on a tenada before um and one of them was this Leaf Hopper an uasa Leaf Hopper which uh was clearly probing the plants much uh without our knowledge of
It and then when they found a plant that was Jasmine defici they started to feed on him and they fed him and they this probing that the that these embo Asal Leaf Hoppers do elicits J signaling too um and to make a long story short we
Spent a lot of time trying to figure out what was the reason why they were able to feed on a jasm deficient plant was it because jasm sigan was was abrogated itself jasm the signal itself was the was the defense molecule or was it some molecule some defense compound that the
That the Jasmine siging was elicited so we took the three Pathways that we knew were jasmine8 active namely the prote Inhibitors the nicotine and the dtgs knocked them out um and then we knocked out all these other steps in the jasm pathway all the way up to the to the
Lipid that releases the me the the 18 carbon molecule from the membrane to start Jasmin biosynthesis and we created a Jasmin sync this is how we made the ultimate defenseless plants we’ simply overexpress a methyl transfer to conjugate jmate with methyl a group methylate to make methyl jasm which is
Totally inactive and then we knocked out the esterase that would cleave the methyl group from the methyl jasm to make it back to Jasmine again so we basically created a sink sucked all the jasm out of the plant volatilized it got rid of it and that made the plant
Totally you know transm inactive and then we planted all those different lines into a field and in the bottom of the field at the end of that fot you see a nice Green alphalpha Field Alfalfa turns out to be a nice host for these Leaf Hoppers um and then we mowed the uh
The alphalpha field drove the leaf Hoppers up into our Plantation and then Quantified the damage and turns out they only damag the jmate deficient lines they didn’t care about the lines that we had knocked out nicotine produce Inhibitors of nban glycosides so we were thinking during this time that it must
Be simply that these were blood hounds for identifying jasm mutants so we spent these we use these insects basically to help us identify mutants of jasm sing natural populations We Gather them up at night and release them into small populations and you could usually find one or two jasic deficient plants in
Each of the native populations scattered throughout the desert so that was great but we really didn’t understand very much about it and we certainly didn’t understand any of the chemistry that was behind this and it clearly required a different approach it required a for genetics approach because we had no idea
Where that what the chemistry was we had to let forward genetics guide us into what the chemistry was involved so in order to do forward chemistry you need a genome all right and I tell you this was not easy because um it’s a pretty big genome 2.3 gigabases it’s repete with
All sorts of little vile repeat elements we struggle with the first generations of PE bio sequencing because we could not get um the DNA through those those P biop pores it turns out the secondary chemistry of the of the uh the plants particularly those zering glycosides clogs those pores so we we actually
Couldn’t get any long reads to be able to do a decent assembly until we had knocked out the D gly sides completely with later generations of P bio we were a to assemble a better long reading we now have a chromosome level assembly which you just published last month in
Pnas Rish Frey a gr student uh responsible for that and then we generate spent 10 years developing a for genetics real population and we gener generated this magic population which stands for a multi-parent advanc generation intercross one that would basically capture a large fraction of the genetic diversity in Nana
Populations so we went out and used my collection of about 420 different accessions of attenuata that I’ve been collecting for the past 30 years screen them for the 26 most variable parents use those 26 parents to do uh 26 by by variant intercross intercross them for four generations seven generations of
Inbreeding to generate uh this magic population which we then would plant out and ask questions about um like Leaf Hopper chemistry um and I wanted tell you a little bit about the solution to that and how we got to the structure so this is just a um a PCA of the genetics
Of those uh of that magic population showing that um the reals all tightly cluster showing very little genetic structure here’s the 26 parents um and one of the problems about doing gwas of course is you know that uh population structure really uh gives you an awful
Lot of false positives you have to get rid of the population structure and this is exactly what this magic population does completely randomizes the genetic back background but captures all that genetic diversity in a nice structured population and so we took this enormous magic population there two replicates of
325 reals and planted them out into the field to phenotype them for all sorts of traits and we grew them in populations where we surrounded the the magic population with the favorite natural host plant of the embasa leaf Hoppers and then of course we harvested them drove the leaf Hoppers into the magic
Population and then tell and tried to figure out what exactly was going on and it was really the Brilliance of um an informatics person in the group that I already introduced that Pang leing who’s now in Shanghai who was able to network the eqtls we got from that data from
That experiment as well as the metabolite qtls and the phyto hormone qtls together to come up with a particular structure this structure right here which has a molecular weight of 347 um uh which is the molecule that was imputed most strongly by Esa feeding um and then to figure out how this
Molecule is actually made in the plant because we in order to test the hypothesis we want to knock it out we want to be able to um put it into another plant uh we managed to recruit a really wonderful synthetic biologist yuchen B who is at Fudan University now
Who was able to reconstruct the entire pathway in yeast um and using the smidgens of information that we were getting from this for genetic screen and some of these some of these genes that were involved in the biosyn is do not have very strong log scores and I
Encourage you to read the science paper I won’t have time to go into it um but it involves some very interesting biosynthetic chemistry but the the real gem here and this is an example about how synthetic biology is going to be so important for this type of work was that
He was able to reconstruct the pathway in a natural host of The Leaf Hoppers that doesn’t have the chemistry doesn’t even had the phen amines in there so he put all the genes that were necessary into Bean which is one of those host plants and was able to make bean
Completely toxic to Leaf Hoppers a bean which is a perfect host for leaf hoppers in the past and of course we’re very interested in this in an agricultural component these Leaf Hoppers are major pests of of tea and we’re in the process of trying to to reconstruct the pathway
Into into tea plants and life um but there was a there’s a there’s a little Point here I want to make that has to do with function and again the my main Takeo message which is the importance of field work and that is has to do with the biosynthesis of this particular
Molecule so the the molecule starts out with calcine there’s two polyphenol oxidases that turn the phenol into a quinone which activates it for the conjugation of the glv the six carbon unit which also has to be activated by the polyphenol oxid to make this conjugation process the important point
I want to make here is it that the particular glv is the Z3 hexan L not the Z2 hexanal now remember what I told you about the Z3 the Z3 is what’s made upon un wounding and the caterpillar turns it into Z2 which then becomes a much more effective Predator attractor so that
Means that there’s perhaps another interpretation than this one to why the caterpillar is doing that one that we’re going to have to go back and revisit and that interpretation is that there is an interaction between the leaf Hopper and manduka about the resistance traits that we need to explore much more carefully
So again this is an example where a functional interpretation is something that you need to constantly go back and revisit to see whether or not you actually have the story correct nature is just as complicated as what’s going on in the Middle East right now and it’s
Very hard to come up with a clean interpretation based on a few laboratory experiments now the last point I want to make and and just to end my my story is that at the same time when we were doing all this stuff with amboa we were also
Taking spit and elicita the entire magic population with these fac factors and we were able to imp compute uh a beautiful spit elicited uh log score which happened at the end of chromosome 5 right there was a beautiful large deletion in a gene called jar 4 now jar
4 is the one that does the conjugation of the isoline amino acid to jasm to make the active signal molecule for jasm signaling so that means that in that magic population was a natural Jasmine mutant that has this very large deltion in uh in this particular essential component of Jasmine siging now what
We’ve gone on to show and I’m not going to show you the data because I don’t have the time for this um is that these plants that lack Jasmine siging are of course defenseless they can’t make that beautiful molecule that I just showed you but they also benefit from not
Having to do that when there’s no herbs around because they have enormous growth Advantage they can grow 20% faster than a normal wild Ty plant simply because of the lack of Defense drag that they have uh from that so there’s this there’s this benefit but an enormous cost uh to
To having this and um we also were able to troll a seed collection that I had made when I was a graduate student so this is a important message for all graduate students do not throw away your samples 30 years later this turned out to be the key thing that made this a
Pnes paper and we were able to show that this major mutation was located in a particular portion of Utah and had been there representing 30% 70% of some populations for at least 10 years and if you know anything about evolutionary biology and ra Fisher’s fundamental theorem of natural uh
Selection you realize that this should not happen this is a major mutation a single Gene major mutation with big Fitness effects that is persisting in a natural population ra Fisher who I have right here is smoking away um predicted that that should not occur because all all
All those type of mutations should have been driven to to fixation very rapidly and we spent most of the paper that uh we just published in pns on this trying to understand how this major mutation is buffered by a whole by the gene Network that is in which it is balanced and I
Don’t have the time to go into all of this um but the point that I want to make and really my ending point here is that it’s basically never too late to do field work and fieldwork with a natural system puts everything into a context that is outside of the human
Intellectual construct and it’s great that theory predicts that something shouldn’t happen but when it does happen one should go back and think about the theory and I I need to thank some um funding agencies of mun society and a bunch of other funding agents who fund this work uh the bringham Young
University who has for the past many years has allowed us to do releases uh on their nature preserve and a whole lot of people who generated some amazing videos that that I shown you here and you for your attention any questions what an excellent talk any questions for
You just realized that body odor can kill so better shower yeah amazing talk um it’s an incredibly complex system and millions of different defense mechanisms that have evolved and strategies on the part of the plant and yet the plant doesn’t have much opportunity to reproduce and transmit genes around from what I
Understood you said that it’s only when fire happens every 100 years or something well with Brom grass invasions it’s happening every four years now um so there there’s actually it’s faster cycling yeah basis is there uh that kind of uh diverse strategy in in plants that um
Sort of reproduce more often have more Generations per year it seems to me to be a lot of uh sort of uh um different strategies when there’s not really much opportunity for that to be selected for oh I think there’s plenty of opportunity for these things to be selected for I
Think you know you’re you’re thinking about agricultural time you know 4 million years has a lot of Generations in it and and you can select for things pretty quickly and I think there’s a there’s also enormous amount of genetic diversity in these natural populations this is one of the great things about
Having uh species that can escape in time this way the populations are incredibly genetically diverse because you’ve got things that were growing four years ago with things growing 100 years ago all coming up in the same population so there’s a lot of genetic material there to select them upon it’s just a
Question of how strong the selection differential is uh for the particular traits um so um I think one should never underestimate the power of natural selection particularly with that type of time frame um and you know when when a fire happens you get millions of seeds
And it goes into the seed bank and it hangs out there and waits for the next fire and the fire could be very local very you know distributed so I’m not at all concerned about the mismatch of the complexity of those traits and the evolution Ary time and the selection
Differentials that were necessary to select for it and and I’m also I just want to think one of the things I’ve also this is what this last p& paper is about is that there is so much more embedding phenotypic embedding in the genetic work networks that plants have and that we
Totally underappreciate just how much compensatory responses uh there are and it doesn’t take a lot of changes of a key full of handful of regulatory elements to switch things around and I think this is what we’re learning from plant breeding is that we’re you know
When you breed for a plant that is able to be you know highly yield producing in a particular habitat it frequently doesn’t involve a lot of genetic change to do that even though it changes a lot of different things Frost tolerance and phenologies and and the like so couple
More questions and then uh we’ll have to close I see a hand run up there yeah go ahead please sure um I was wondering you talk very rly about domestication and so indirect defenses do do you know if domestication has changed uh prop or in particular tobacco uh and and it it
Produces Less volatiles in general it gets less ofces yeah yeah those are excellent questions I I haven’t really studied cultivated tobacco very much um I do know that cultivated tobacco does not respond very strongly to these FC’s and there’s not much of an ethylene burst so that there is very little
Downregulation of nicotine when the caterpillar attacks them in this plant the cat the plant downregulates ad ntin production very strongly when the caterpillar attacks it and it turns out it’s because there’s a whole other Story the caterpillar is able even though it’s excreting most of the nicotine out of
Its gut through its digestive system it sequesters a little bit into its spiracles and it has this defensive halosis it puffs when it’s attacked by spiders it Puffs out a little nicotine breath at it um and uh that of course is co-opted from the plant so that’s just
One example of the things that we know are different between a tenada and the many polyploid varieties that we smoke um as far as I can tell when we domesticated tobacco we were interested in leaf size um very large leaves so you can have more stuff to smoke um noos
Attenuata the word attenuata means small Leaf attenuated leaf and the Anastasia actually the the Native Americans they five tribes I don’t shouldn’t use that term anastasi um they they didn’t smoke leaves they smoked the capsules um and the capsules have are full of nicotine rich tricomes and and light but um I just
Haven’t I don’t really find it that interesting to explore function in a domesticated plant because it doesn’t make any sense all of that genetic architecture in a domesticated plant has been dragged Along by the artificial select for yield and it’s all done in some crazy way and sure a lot of things will
Get lost a lot of things will be gained and you try to make sense of that it’s like some scrambled you know idiotic genome so I would much prefer to spend my efforts as a scientist working on a plant that I know is hone by natural selection and it makes sense to be
Thinking about adaptive consequences of the particular architecture that’s there I’m not sure if that makes sense to you but I I well in a way it would explain why we we can’t get rid of pests by domestication we have vola yeah yeah and this would be easy to engineer back into
Crops no no big deal they have jasm made signaling you just need the receptor and you need to tack it onto a couple of good volatiles the Predators will learn the volatiles there’s nothing in intrinsic about those volatiles that attracts Predators it’s all a matter of
Learning we’ll do a few more and then there’ll be a discussion tomorrow morning you’re welcome to attend for quite some time that Dr BWI will be available so hopefully you can attend and discuss details but I see a couple more hands go up so let’s let’s take a
Few more a first one I saw from back there please go ahead so you that this is entirely um dominated by national selection and yet we have in the archaological record and historical record we have a lot of indication that indigenous peoples have been uh cultivating land rces of poana for
Hundreds of thousand years do you have uh any ways that you can look at population genetics in this class to determine whether or not or to what extent uh human cultivation and Indigenous agriculture has impacted the populations these are excellent questions and I wish I knew more all I
All I know is that the pyot Shon apparently burn the Sage Brush to promote this and that they traded the seeds and you can definitely find genotypes along the trading that are coming out of Utah and going up to Washington Washington State um but aside from that I don’t think there’s really
Much cultivation going on other than burning the sage bush and having this natural fire six so I don’t I don’t think there’s been a lot of direct selection of the Native they weren’t cultivating it in the in the standard sense and selecting for traits that were important the plant makes godz zillion
Amounts of nicotine they didn’t need to do anything more than smoke it um for the purposes that they were using it for so but it’s a great question and I think that for um plants that are making other sorts of things that are domesticated you have a that is a much more important
Concern um um great great question thanks I had one there and then last one to you go ahead please uh I was just interested to know uh if you are so you are utilizing your uh M FL against insects right I was interested like if you are utilizing them for long
Path like Sy which is a big problem in tobacco right so yeah yeah yeah so um if it’s not a natural thing that I see in Utah I don’t care okay so um cotus Syringa is a wonderful lab rat pathogen that you use to elicit plants to activate salate
Signaling um I don’t see it as a pathogen in Utah the pathogenic problems that we have in Utah are mostly fusarium Aleria fungal pathogens and we know a lot about that we have some microbiome papers that show about the plant is has a sterile seed once it germinates it
Starts to recruit a microbiome that microbiome is super important in protecting it against fusarium uh root rots and things like that and so it seems to use microbiomes to deal with the pathogenic World which probably evolves faster than when you have a for 400 year life cycle yeah it’s an annual
Plant but it really is a 400y year cycle yeah but excellent question yeah go ahead I’m interested in the sort of temporal element you had uh the plant uh transporting Su gr to the roots oh yeah uh and so then at some point how do know
That now is the time that’s one element caterpillars causing a change in the way that the flower is presented makes it more difficult for the the moths to get nature and then that m is inhibited from laying eggs which would produce a new generation I don’t know how many
Generations of caterpillars you have in only one yeah yeah it’s only one generation and usually only one caterpillar per plant the plants you know only get so big and the caterpillar is a br size thing so um they will wipe it out if there’s more than one when
When the uh caterpillar split spit is no longer there then plant decides at time they switch back to the to the moth pollinated one yeah so it’s about six days of feeding will get all of the flowers into this hummingbird pollinated scenario and then if there’s no more caterpillars feeding they switch right
Back again that happens actually faster than six days so and it’s system H you don’t need a nervous system for you don’t need a nervous system no it’s you know well you just need a jasine s system to do that and it’s you need to have a clock that you can hijack and
Stop that you know that waving behavior um and that’s that’s the name trick of it uh um you had a first question about the T the oh yeah so the timing of the so that happens um during during a massive defoliation event when the catapillar are really stripping down a
Plant that’s when all of this sucros that it’s being synthesized by the stem and the remaining leaves Goes Down And once the caterpillars stop feeding then uh the then you have the normal back to seed filling structure so then sucos then goes back up it turns out the plant
Basically becomes a stem as as you might have seen there were very Brown stems there and they will able to mature all of their seeds with no leaves at all so the the stem itself is photosynthetic enough the peduncle becomes really fat and the and the flower capsule the seel
Supply the remaining photosynthate that’s necessary to fill the seeds so what we’re looking at is only when there’s been a rain event watering Again The Roots get wet and uh there’s an opportunity to grow new flowers that’s when that carbon that is down in The Roots gets Mo mobilized back up again
And uh going so it’s in this sort of it becomes basically a cactus and becomes basically a stem um and then it and then it just becomes a stem with flowers that it reactivates uh so get it gets about 10% more flowers from this reactivation response so it’s not a full tolerance is
Not a full compensation but it it buffers that’s enough yeah enough to do something yeah thank you great I’m going to have to close the session but I was remiss I wanted to make sure I do mention this uh to describe the bendalo memorial Lector ship in a sentence or
Two so the Dr Victor M bendalo Memorial lectur ship was created through a a bequest to bring internationally distinguished lectures to deliver seminars in the field of plan science and to share their knowledge with students and staff at the University and no no doubt we had that today so once
Again join me in thanking Dr