Using a novel route, an Indian researcher has been able to increase wheat grain yield by 20% and also improve the resilience of wheat to environmental stress such as drought. By using a precursor that enhances the amount of a key sugar-signalling molecule (trehalose-6-phosphate (T6P)) produced in wheat plant, Dr. Ram Sagar Misra, from the Department of Chemistry, University of Oxford and currently with the Department of Chemistry, Shiv Nadar University, Greater Noida, has been able to increase the amount of starch produced and, therefore, the yield.
The T6P molecule stimulates starch synthesis, which in turn, increases the yield. Since the pathway of T6P molecule is the same in other plants, the yield can potentially be increased by using suitable precursors. The results were published in the journal Nature. Dr. Misra is one of the authors of the paper.
Dr. Misra and researchers from UK used four precursor compounds to increase the amount of T6P produced in the plant. While genetic methods can increase the T6P level two-three fold, the four precursor compounds were able to achieve 100-fold increase in the sugar-signalling molecule level compared with plants that did not receive the molecule. Dr. Misra and others tested the effect of four precursors by dissolving the molecule in water and feeding this to the roots of Arabidopsis thaliana plants. Compared with controls, the precursor-treated plants produced higher amount of T6P molecule and starch when exposed to sunlight.
In field trials using wheat, a tiny amount of precursor given to the plant increased the yield significantly — the grains produced were bigger as the amount of starch content in the grains increased by 13-20% compared to controls that got only water. “A particular precursor molecule — ortho-nitrophenyl ethyl — showed the best results in both A. thaliana plants and wheat studies,” he says. “The uptake of this molecule by the plants was much more than the other three molecules and the precursor took less time to release T6P.”
To study the resilience of wheat to drought-like conditions when treated with the precursor molecules, the researchers carried out two different studies.
Resilence to drought
In the first case, four-week-old wheat plants already treated with the precursor molecules were not watered for nine days to simulate a drought-like condition. “The plants were almost dying. When we watered the plants after nine days, only those that were pre-treated with the precursors were able to regrow while the control plants did not survive,” says Dr. Misra.
In another experiment, four-week-old wheat plants that were not watered for nine days were sprayed with the precursor molecules. “The regrowth of plants sprayed with the molecule was substantial when the plants were watered a day after treatment. We saw regrowth of new tissue and also survival and growth of existing tissue,” Dr. Misra says. “This also showed that the molecule could enter the plants directly when sprayed.”
“These two studies showed that wheat plants were able to survive environmental stress if treated with the precursors. The molecule 2 (dimethoxy(ortho-nitro)benzyl) was better in battling stress,” he says. More trials on a larger scale are needed to confirm the role of the precursor molecules in increasing yield and withstanding drought-like conditions.