Transgenic Rice with Improved Water Use Efficiency

Rice typically uses up to three times more water as compared to other food crops such as maize and wheat and consumes around 30 percent of the fresh water used for crops worldwide. In conditions where there is limited water supply, it is important to have crops that can use water efficiently and still generate sufficient biomass. A group of scientists from the US, Italy, India, Israel, Mexico and the Netherlands showed that the expression of the Arabidopsis HRD gene in rice improves its water use efficiency and biomass production by limiting transpiration and enhancing photosynthesis. The researchers found that the biomass of HRD rice increased by around 50 percent under conditions of drought, mostly by adaptive increase in root biomass, compared to the unmodified version of the same type of rice. In addition to its water use efficiency, the transgenic rice was also found to be salt tolerant.

The expression of a dicot HRD gene in a monocot crop rice supports broad applicability of the gene and underlying mechanism of enhanced photosynthetic assimilation in a wide range of crop plants under well irrigated and drought-stressed environments. This might be useful to increase the biomass of grasses and other crops useful for carbon fixation and use as a sustainable bioenergy source.

Read the abstract at http://www.pnas.org/cgi/content/abstract/0707294104v1 or the full paper at http://www.pnas.org/cgi/reprint/0707294104v1