Navigation Links
Newly identified enzymes help plants sense elevated CO2 and could lead to water-wise crops
Date:12/13/2009

Biologists have identified plant enzymes that may help to engineer plants that take advantage of elevated carbon dioxide to use water more efficiently. The finding could help to engineer crops that take advantage of rising greenhouse gases.

Plants take in the carbon dioxide they need for photosynthesis through microscopic breathing pores in the surface of leaves. But for each molecule of the gas gained, they lose hundreds of water molecules through these same openings. The pores can tighten to save water when CO2 is abundant, but scientists didn't know how that worked until now.

A team led by Julian Schroeder, professor of biology at the University of California, San Diego, has identified the protein sensors that control the response. Enzymes that react with CO2 cause cells surrounding the opening of the pores to close down they report in the journal Nature Cell Biology online December 13.

The discovery could help to boost the response in plants that do not take full advantage of elevated levels of the gas, Schroeder says. "A lot of plants have a very weak response to CO2. So even though atmospheric CO2 is much higher than it was before the industrial age and is continuing to increase, there are plants that are not capitalizing on that. They're not narrowing their pores, which would allow them to take in CO2, while losing less water," he said. "It could be that with these enzymes, you can improve how efficiently plants use water, while taking in CO2 for photosynthesis. Our data in the lab suggest that the CO2 response can be cranked up."

Plants lose 95 percent of the water they take in to evaporation through these pores, also called stoma. Modifying crops to be more responsive to CO2 could help farmers meet demand for food as competition for water increases. In California, for example, 79 percent of water diverted from streams and rivers or pumped from the ground is used for agriculture according to the California Department of Water Resources.

Schroeder's team identified a pair of proteins that are required for the CO2 response in Arabidopsis, a plant commonly used for genetic analysis. The proteins, enzymes called carbonic anhydrases, split CO2 into bicarbonate and protons. Plants with disabled genes for the enzymes fail to respond to increased CO2 concentrations in the air, losing out on the opportunity to conserve water.

Several types of cells in plant leaves contain carbonic anhydrases, including those responsible for photosynthesis, but Schroeder's team showed that the enzymes work directly within a pair of cells, called guard cells, that control the opening of each breathing pore. By adding normal carbonic anhydrase genes designed to work only in guard cells they were able to restore the CO2-triggered pore-tightening response in mutant plants.

Adding extra copies of the genes to the guard cells actually improved water efficiency, the researchers found. "The guard cells respond to CO2 more vigorously," said Honghong Hu, a post doctoral researcher in Schroeder's lab and co-first author of the report. "For every molecule of CO2 they take in, they lose 44 percent less water."

The action of carbonic anhydrases is specific to changes in CO2, the researchers found. Mutant plants still open their pores in response to blue light, a sign that photosynthesis can begin. And their pores also shut when water is scarce, a response mediated by a plant drought-stress hormone.

Photosynthesis continued normally in the mutants as well, suggesting that altering CO2 sensitivity wouldn't stunt growth good news if the goal is to engineer drought-resistant crops with robust yields.

But saving water and surviving heat involves a tradeoff for plants: Evaporation of water through the pores also cools the plant, just like sweat cools human beings. If future growing conditions are hotter and drier, as they are predicted to be in some parts of the world, then modifications to the CO2 response will need to be carefully calibrated.


'/>"/>

Contact: Julian Schroeder
scinews@ucsd.edu
University of California - San Diego
Source:Eurekalert

Related biology news :

1. Newly discovered mechanism allows cells to change state
2. Newly discovered fat molecule: An undersea killer with an upside
3. Newly found DNA catalysts cleave DNA with water molecule
4. Newly discovered gene fusion may lead to improved prostate cancer diagnosis
5. Newly discovered snow roots are evolutionary phenomenon
6. Newly discovered reactions from an old drug may lead to new antibiotics
7. Newly discovered epidermal growth factor receptor active in human pancreatic cancers
8. Newly discovered gene plays vital role in cancer
9. DNA evidence is in, newly discovered species of fish dubbed H. psychedelica
10. Newly described contaminant sources in Katrina-flooded homes pose health risks
11. UC Davis research shows that newly discovered drug reduces heart enlargement
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:12/16/2016)... Dec 16, 2016 Research and Markets has ... - Global Forecast to 2021" report to their offering. ... The biometric vehicle ... at a CAGR of 14.06% from 2016 to 2021. The market ... projected to reach 854.8 Million by 2021. The growth of the ...
(Date:12/15/2016)... Germany , December 15, 2016 ... provider, today announced an agreement with NuData Security, an ... forces. The partnership will enable clients to focus on good ... local data protection regulation. ... In order to provide a one-stop fraud ...
(Date:12/15/2016)... 2016 ... Research and Markets has announced the addition of the ... The report forecasts the global military biometrics market to grow at ... report has been prepared based on an in-depth market analysis with inputs ... prospects over the coming years. The report also includes a discussion of ...
Breaking Biology News(10 mins):
(Date:1/17/2017)... DIEGO , Jan. 17, 2017  An ... School of Medicine and St. Boniface Hospital Albrechtsen ... for peripheral neuropathy, an unmet health need affecting ... the Journal of Clinical Investigation, their results identify ... that prevent and reverse neuronal injury in animal ...
(Date:1/17/2017)... 2017  Zimmer Biomet Holdings, Inc. (NYSE and SIX: ... sales and earnings conference call will be broadcast live ... 8 a.m. Eastern Time.  A news release detailing the ... 7:30 a.m. Eastern Time the morning of the conference ... accessed via Zimmer Biomet,s Investor Relations website at ...
(Date:1/17/2017)... NEW YORK , Jan. 17, 2017 /PRNewswire/ ... mobile health coaching, is the first to offer ... and obesity. Noom,s Spanish diabetes prevention ... expand the reach and accessibility of lifestyle interventions ... of developing these conditions. Noom,s robust food database, ...
(Date:1/17/2017)... -- Only nine percent of U.S. consumers believe pharmaceutical and ... percent believe health insurance companies do, according to a ... U.S. adults believe health care providers (such as doctors ... (23%). "We are in the midst of ... vice president of reputation management and public affairs at ...
Breaking Biology Technology: