Researchers show potential for improved water use efficiency in field-grown plants

Water deficit is currently one of the most important limiting factors of global agricultural productivity, a factor further exacerbated by global climate change according to a report on the water from 2019 of the Food and Agriculture Organization of the United Nations (FAO). As a result, researchers around the world have been working to improve the efficiency of water use in crops to better cope with water scarcity conditions.

In a recent study published in the Journal of Experimental Botany, a team from the University of Illinois, the Volcani Center (Agricultural Research Organization, Israel) and the University of Cambridge discovered that by overexpressing a sugar-sensing enzyme, called hexokinase, in tobacco crops grown in the field.

Tobacco was used as a model society because it is relatively easy to work in the laboratory, greenhouse and in the field. Results in this crop can be seen at a much faster rate than in food crops, which are more difficult and take longer to modify and grow. Therefore, tobacco was chosen as the initial lifestyle test to see if similar results could be proven. After showing the success of the model crop, researchers can then confidently mirror developments in food crops, such as cassava, cowpea, rice, and soybeans.

This study demonstrates the potential to generate plants with more conservative water use throughout the growing season under field conditions and moderate water limitation, without significant yield penalty. For farmers, this could reduce soil water depletion throughout the growing season and reduce reliance on irrigation.

a research project worldwide which aims to increase global food production by developing food crops that more efficiently convert solar energy into food with support from the Invoice & Melinda Gates Foundation, Basis for Food items & Agriculture Investigation, and United kingdom International, Commonwealth & Enhancement Business.

Plants open tiny pores in their leaves, called stomata, to absorb CO2. However, when the pores are open, water can also escape through perspiration. This leaves plants with a trade-off between losing too much water to absorb CO2.

pore closure,” said Liana Acevedo-Siaca, who led this study in Illinois during her time as a postdoctoral researcher. “Previous studies have shown that genetic manipulation of signal elements that trigger stomatal movement, such as overexpression of Arabidopsis Hexokinase 1 (AtHXK1) in guard cells, can stimulate stomatal closure and adjust this trade-off for plants. ” Acevedo-Siaca now works as an Associate Scientist in the Global Wheat Program at the Intercontinental Maize and Wheat Improvement Center (CIMMYT) in Mexico.

It has been previously shown that targeted expression of AtHXK1 guard cells can improve WUE in crops, as well as their tolerance to drought conditions and stress. salinity, as hexokinase signals to the pores that there is enough sugar, eliminating the need to fix more CO2. However, these previous studies were only evaluated on crops grown in controlled environments, such as greenhouses.

“To improve our understanding of the potential benefits of AtHXK1 Targeted to guard cells, our study used two homozygous transgenic lines expressing AtHXK1 and one line that exhibited guard cell-targeted AtHXK1 overexpression that were assessed against field-grown wild-style cells. said Johannes Kromdijk, assistant professor at the University of Cambridge, who started this study in 2018. “Our results confirmed that constitutive AtHXK1 overexpression decreases productivity. We also showed that guard cell-targeted overexpression of AtHXK1 could enhance iWUE relative to wild-type without negatively affecting CO2 assimilation. Yet, this difference was highly dependent on leaf age, and recent rainfall could eliminate performance differences.

The RIPE project and its sponsors are committed to ensuring access and making the project systems available to the farmers who need them most.

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