Discovery provides insights on how plants respond to elevated CO2 levels

Jul 06, 2014
Credit: Notneb82, Wikimedia Commons

Biologists at UC San Diego have solved a long-standing mystery concerning the way plants reduce the numbers of their breathing pores in response to rising carbon dioxide levels in the atmosphere.

In a paper published in this week's early online edition of Nature, they report the discovery of a new genetic pathway in plants, made up of four genes from three different gene families that control the density of breathing pores—or "stomata"—in plant leaves in response to elevated CO2 levels.

Their discovery should help biologists better understand how the steadily increasing levels of CO2 in our atmosphere (which last spring, for the first time in recorded history, remained above 400 parts per million) are affecting the ability of plants and economically important crops to deal with and drought. It could also provide agricultural scientists with new tools to engineer plants and crops that can deal with droughts and high temperatures like those now affecting the Southwestern United States.

"For each carbon dioxide molecule that is incorporated into plants through photosynthesis, plants lose about 200 hundred molecules of water through their stomata," explains Julian Schroeder, a professor of biology who headed the research effort. "Because elevated CO2 reduces the density of stomatal pores in leaves, this is, at first sight beneficial for plants as they would lose less water. However, the reduction in the numbers of stomatal pores decreases the ability of plants to cool their leaves during a heat wave via water evaporation. Less evaporation adds to heat stress in plants, which ultimately affects crop yield."

Schroeder is also co-director of a new research entity at UC San Diego called "Food and Fuel for the 21st Century," which is designed to apply basic research on plants to sustainable food and biofuel production.

"Our research is aimed at understanding the fundamental mechanisms and genes by which CO2 represses stomatal pore development," says Schroeder. Working in a tiny mustard plant called Arabidopsis, which is used as a genetic model and shares many of the same genes as other plants and crops, he and his team of biologists discovered that the proteins encoded by the four genes they discovered repress the development of stomata at elevated CO2 levels.

Using a combination of systems biology and bioinformatic techniques, the scientists cleverly isolated proteins, which, when mutated, abolished the plant's ability to respond to CO2 stress. Cawas Engineer, a postdoctoral scientist in Schroeder's lab and the first author of the study, found that when sense atmospheric CO2 levels rising, they increase their expression of a key peptide hormone called Epidermal Patterning Factor-2, EPF2.

"The EPF2 peptide acts like a morphogen which alters stem cell character in the epidermis of growing leaves and blocks the formation of stomata at elevated CO2," explains Engineer.

Because other proteins known as proteases are needed to activate the EPF2 peptide, the scientists also used a "proteomics" approach to identify a new protein that they called CRSP (CO2 Response Secreted Protease) which, they determined, is crucial for activating the EPF2 peptide.

"We identified CRSP, a secreted protein, which is responsive to atmospheric CO2 levels," says Engineer. "CRSP plays a pivotal role in allowing the plant to produce the right amount of stomata in response to the concentration of CO2 in the atmosphere. You can imagine that such a 'sensing and response' mechanism involving CRSP and EPF2 could be used to engineer crop varieties which are better able to perform in the current and future high CO2 global climate where fresh water availability for agriculture is dwindling."

The discoveries of these proteins and genes have the potential to address a wide range of critical agricultural problems in the future, including the limited availability of water for crops, the need to increase water use efficiency in lawns as well as crops and concerns among farmers about the impact heat stress will have in their crops as global temperatures and CO2 levels continue to rise.

"At a time where the pressing issues of climate change and inherent agronomic consequences which are mediated by the continuing atmospheric CO2 rise are palpable, these advances could become of interest to crop biologists and climate change modelers," says Engineer.

Explore further: Biologists develop nanosensors to visualize movements and distribution of plant hormone

More information: Carbonic anhydrases, EPF2 and a novel protease mediate CO2 control of stomatal development, Nature, DOI: 10.1038/nature13452

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User comments : 24

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Steve 200mph Cruiz
4.3 / 5 (8) Jul 07, 2014
I love the lack of comments from the "actions don't have consequences" crowd on these topics.
Excess CO2 emissions are a real phenomenon, that's why you are all ignored when scientists go to work.

But if plants themselves will have trouble adapting to the altered climate, will this cause GMOs to become a standard instead of a luxury? I have the sneaking suspicion that we will eventually destroy all animal and plants on this planet if they are not "efficient" enough to sustain our gluttony. What option do we really have? I hate to take the pessimist side, but I'm starting to think that most living things that are not immediately useful economically will just go extinct, we'll just have global habitation with the only thing driving economic development being religious wars and people fighting for power.

A bland world full of assembly lines to sustain a bunch of losers who don't appreciate anything, the great Fermi Paradox.
antigoracle
1.4 / 5 (10) Jul 07, 2014
I love the gullibility of the AGW Chicken Littles.
It's an established fact that plants have not only survived in higher CO2 levels, but actually flourished.
You must believe there are no Polar bears left.
thermodynamics
4.6 / 5 (9) Jul 07, 2014
AntiEm: You say:
It's an established fact that plants have not only survived in higher CO2 levels, but actually flourished.


Yes, but not the plants we use for crops.

Are you saying we should be eating ferns and Annularia?

Don't forget that evidence shows past changes in CO2 took a lot longer than this change and the plants that existed then don't exist now.

Your short-sighted view is interested. Are you related to Mr. Magoo?
antigoracle
1.4 / 5 (9) Jul 07, 2014
For the idiot above.
http://www.omafra...-077.htm
thermodynamics
4 / 5 (8) Jul 07, 2014
For the idiot above.
http://www.omafra...-077.htm


AntiEm: That is, actually, an interesting article. However, please note it is for a greenhouse where water vapor and temperature are also controlled. The issue is the ability of plants to stand shock in hotter climates and less water. If everything were in a controlled climate it would go a long way toward making things easier. However, that is unlikely as the climate changes. Are you proposing putting all agriculture in buildings?
Steve 200mph Cruiz
4.4 / 5 (7) Jul 07, 2014
Antigoracle,

I know how plants work, that's one of the first things you learn in a biology class. Just because you don't understand the implications of this article or the fact that fossil fuel beds come from fossils and burning them realises co2 previously stored in the ground into the atmosphere creating a discrepancy that we call global warming, doesn't make me chicken little. I'm more of a George Orwell or aldous Huxley.
antigoracle
1 / 5 (10) Jul 08, 2014
Trust me, the last thing you AGW Chicken Littles should boast about, is that you know science.
http://www.geocra...ate.html
Captain Stumpy
5 / 5 (4) Jul 08, 2014
Trust me, the last thing you AGW Chicken Littles should boast about, is that you know science.
@antigoracle
well, here is your chance to prove us all wrong: thermodynamics posted a Bounty:

http://dialogueso...nge.html
All you have to do is go to this page, prove that AGW is incorrect and win $30,000.
So, all of you who can prove AGW is wrong (by falsifying it) can pick up your loot.
Here is the opportunity for you to take your pet view and WIN.
all you gotta do is prove your point of view and you get $$$$, fame and recognition.

I patiently await your attempt at this...
Like Thermodynamics said-
I guess I am just left out on this one because I understand the physics and know you can't win.
Just let us know when you collect
I know I can't win.
guess I will have to leave it up to Uba, cd85, anti-g and jdhooker

show us "chicken littles" how its done aunti-g!

antigoracle
1.3 / 5 (10) Jul 08, 2014
There is that boast again from the AGW Chicken Littles - I understand the physics.
So, tell me Chickens, if everything that the Cult wants, to curb CO2, is done, would that stop the glaciers and ice sheets from melting.
Captain Stumpy
3.7 / 5 (6) Jul 08, 2014
There is that boast again from the AGW Chicken Littles
@anti-G
what boast?
this is YOUR time to shine! this is YOUR opportunity to prove to all of us "AGW Chicken Littles"[sic] that you are correct and we know nothing....AND you get to make some money, get famous and travel the world to boot!
http://dialogueso...nge.html

If you DON'T try, it only proves that you are incapable, and that you have zero evidence, which means that you are no better than a TROLL and SPAMMER.

it is SO easy... and since you are so sure! go for it!

There is no entry fee; You must be 18 years old or older to enter; prove, via the scientific method, that man-made global climate change is not occurring;

supamark23
4.3 / 5 (6) Jul 08, 2014
I love the gullibility of the AGW Chicken Littles.
It's an established fact that plants have not only survived in higher CO2 levels, but actually flourished.
You must believe there are no Polar bears left.


How does it feel to have no use to humanity other than being a really ignorant troll? It's like, the world would actually be a better place with you gone... maybe you should get to work on making that happen - it would be your one gift to humanity, disposing of your otherwise worthless self.
supamark23
3.7 / 5 (6) Jul 08, 2014
Trust me, the last thing you AGW Chicken Littles should boast about, is that you know science.
http://www.geocra...ate.html


Kill yourself. Seriously, do us all a favor and end it.
ryggesogn2
1 / 5 (8) Jul 08, 2014
I love the gullibility of the AGW Chicken Littles.
It's an established fact that plants have not only survived in higher CO2 levels, but actually flourished.
You must believe there are no Polar bears left.


How does it feel to have no use to humanity other than being a really ignorant troll? It's like, the world would actually be a better place with you gone... maybe you should get to work on making that happen - it would be your one gift to humanity, disposing of your otherwise worthless self.

Typical response of an intolerant socialist, violence.
Too bad the Paul Ehrlich population control disciples don't follow in the path of the Shakers.
antigoracle
1.5 / 5 (8) Jul 08, 2014
Trust me, the last thing you AGW Chicken Littles should boast about, is that you know science.
http://www.geocra...ate.html


Kill yourself. Seriously, do us all a favor and end it.

Ouch!! I thought turds had no nerves, but it appears I may have touched one.
That you have no brains, I'm certain.
thermodynamics
5 / 5 (6) Jul 08, 2014
Anti and Rygg: Take the opportunity to prove us all wrong. Enter the contest, falsify AGW theory and win $30K. You talk about the theory being wrong, all you have to do is enter, win, and brag about how right you are. Simple - but you have no idea of how to do that - do you?

Here is your chance to prove all of us wrong. I would, personally, concede to you that you were right. All you have to do is to falsify AGW:

http://dialogueso...nge.html

Really, how hard can it be considering you have said how easy it is to prove AGW is false.

Let us know when you have won. But until then, don't tell us AGW is wrong because have not shown it is. Instead you have just ranted.

Now is the time. Go prove it.

Of course the other one with the perfect model of the atmosphere is "The Alchemist." He says he has a perfect model that shows AGW is wrong. Go collect your money Alche.
antigoracle
1 / 5 (7) Jul 08, 2014
Thermo, it's most unfortunate 30K can't buy you a brain, as you need it to comprehend the proof you seek.
antigoracle
1 / 5 (6) Jul 08, 2014
thermodynamics
5 / 5 (3) Jul 08, 2014
https://www.youtube.com/watch?v=XDI2NVTYRXU


AntiEm: I can see why you are reluctant to take on the challenge. Anyone dumb enough to be posting this connection as a reason for falsifying AGW hasn't got a lick of sense. You have to do a lot better than this to win that prize. Keep going.

Just remember that just because heating led CO2 in the past does not mean it is not CO2 leading heating now. I know it is hard for you to understand that we didn't have power plants in the past, but if you read your little picture books and see, there were none 1000 years ago. However, they are here now and they are increasing the CO2 content of the atmosphere. I know it is hard for you to read a graph, but you really should look at the Keeling curve.

Keep studying. I'm pulling for you to win that prize. You just have to do a lot better than this.
antigoracle
1 / 5 (6) Jul 09, 2014
Thermo, get a brain and then I'll give you the proof, until then any proof is futile.
thermodynamics
5 / 5 (4) Jul 09, 2014
Thermo, get a brain and then I'll give you the proof, until then any proof is futile.


AntiEm: I'm not the one who needs the proof. That isn't my web site. I guess you are a bit confused (as usual). All you have to do is to show them your magic that you think you have up your sleeve and you should be $30K richer. If you only had a brain...
antigoracle
1 / 5 (6) Jul 09, 2014
I do have the proof, but there is one issue left, and since you know the AGW science, perhaps you can help.
If we do everything the AGW Cult wants, to curb CO2, would that stop the glaciers and ice sheets from melting?
supamark23
3.7 / 5 (3) Jul 09, 2014
I love the gullibility of the AGW Chicken Littles.
It's an established fact that plants have not only survived in higher CO2 levels, but actually flourished.
You must believe there are no Polar bears left.


How does it feel to have no use to humanity other than being a really ignorant troll? It's like, the world would actually be a better place with you gone... maybe you should get to work on making that happen - it would be your one gift to humanity, disposing of your otherwise worthless self.

Typical response of an intolerant socialist, violence.
Too bad the Paul Ehrlich population control disciples don't follow in the path of the Shakers.


Too bad your parents didn't smother you at birth - I'm sure they regret that as well seeing how poorly you turned out. Oh, and I didn't advocate violence - suicide can be quite non-violent, just start walking into the ocean and drown, no violence there.
Captain Stumpy
4 / 5 (4) Jul 09, 2014
I do have the proof
@anti-g
if you had the proof, you would also have the $30,000
since you haven't won the $30,000, we can now establish the fact that you have no proof, therefore you are nothing but a charlatan attempting to TROLL

PROVE it to the site, since you are SO SURE
http://dialogueso...nge.html

I will add an additional 50% if you are successful
with an option on land that borders the Buffalo River

now all you have to do is go prove yourself and your science to the site and win
antigoracle
1.7 / 5 (6) Jul 09, 2014
How does it feel to have no use to humanity other than being a really ignorant troll? It's like, the world would actually be a better place with you gone... maybe you should get to work on making that happen - it would be your one gift to humanity, disposing of your otherwise worthless self.

Oh, and I didn't advocate violence - suicide can be quite non-violent, just start walking into the ocean and drown, no violence there.
Too bad your parents didn't smother you at birth - I'm sure they regret that as well seeing how poorly you turned out. Oh, and I didn't advocate violence - suicide can be quite non-violent, just start walking into the ocean and drown, no violence there.
--supaturd
Wow!!
Jolly good then, and all those sort of things.
Moron.