Seed World

Closed Door: Plants With A Stoma For Drought

Deflectors reduce dust risk.

In a paper published in Nature Communications, an international team led by researchers at the University of Illinois reports how it improved the environmental performance of a tobacco plant to use 25% less water without compromising the crop’s yield.

The team increased expression of one gene, Photosystem II Subunit S (PsbS), which caused partial closure of the plant’s stomata, the microscopic pores in leaves that allow water to escape during transpiration and carbon dioxide to enter for photosynthesis.

And because all plants have the gene, the team suggests that their genetic manipulation should be effective across all crops.

“These plants had more water than they needed, but that won’t always be the case,” says Katarzyna Glowacka, a postdoctoral researcher at the University of Illinois and the Polish Academy of Sciences, who led the research. “When water is limited, these modified plants will grow faster and yield more – they will pay less of a penalty than their non-modified counterparts.”

PsbS protein plays a key role in signalling information about the quantity of light available. By increasing PsbS, say the researchers, the plant reacts as though there is not enough light energy for photosynthesis, closing stomata because carbon dioxide is not needed to fuel the process.

The research is part of Realizing Increased Photosynthetic Efficiency (RIPE), a programme supported by the Bill & Melinda Gates Foundation, the US Foundation for Food and Agriculture Research and the UK Department for International Development.


Stoma Credit: Smita Kurup/Rothamsted ResearchStoma Credit: Smita Kurup/Rothamsted ResearchOpen and closed: Stomata of Arabidopsis thaliana, showing red chloroplasts in the guard cells along with actin filaments, identified by talin fused to green fluorescent protein                                                Credit: Smita Kurup/Rothamsted Research
Rothamsted Research was asked to comment on inquiries from the media:
“This paper looks like a pretty significant breakthrough but what do the experts say on the significance of this research in the quest to feed the growing global population while conserving scarce water resources.

“Could you ask them whether applying something that has worked in a tobacco plant to conventional crops is as straightforward as the paper’s accompanying press release suggests or could it potentially be very difficult?

Comment from Rothamsted Research

Matthew Paul, Plant Scientist (specialising in molecular physiology and plant biochemistry) in Rothamsted’s Department of Plant Sciences:
“This interesting study in tobacco shows how it may eventually be possible to engineer crops that require less water.

“According to the study, overexpressing a photosynthesis gene (for a Photosystem II subunit) reduces stomatal opening without restricting CO2 uptake; as a consequence, plants lose 25% less water than in unengineered plants.

“As this photosynthesis gene is universal, there is potential for translating this research to crops. However, the engineered plants produced less biomass; and any negative impact on yield like this would not be tolerated by breeders, farmers, agribusiness.

“Additionally, it would need to be ensured that crops did not overheat in hot weather due to less evaporative cooling. And there is need for drought testing.

“A next challenge would be to see if the approach works in elite varieties of major crops without negatively impacting their ability to yield under a range of environmental conditions commonly encountered in agriculture.”

Source: Rothamsted Research