Kearney and West Side RECs: Studies of sorghum's adaptation to drought push the frontiers of crop improvement

Abstract

News from the RECs Starting with this issue, California Agriculture will publish a regular feature on projects at UC ANR’s Research and Extension Centers Kearney and West Side RECs: Studies of sorghum’s adaptation to drought push the frontiers of crop improvement W ith the climate changing and demands on water resources growing, crops that can survive drought are near the top of the global agricultural wish list. But drought tolerance has so far confounded plant researchers. One problem is that it involves many complex relationships: a host of genes that activate when a plant is short of water; soil microbes that interact with plant roots. Another difficulty has been that plants respond differently to water stress when they are grown outdoors rather than indoors, meaning that greenhouse-based findings haven’t translated well to the field. Peggy Lemaux Two new research projects involving the Kearney and West Side Research and Extension Centers (RECs) are taking on these challenges, using a mul- tifaceted, field-based approach West Side REC director Bob Hutmacher with sorghum as their subject. collects a soil sample next to a sorghum The knowledge gained could lead plant to evaluate the microbial eventually to the ability to control population around sorghum roots. the mechanisms of drought toler- ance and the development of im- proved varieties of sorghum and other crops. “We may be able to find ways to manipulate those character- istics to enable drought toler- ance and water use efficiency,” said Kearney REC director Jeff Dahlberg. “That’s the ultimate pie-in-the-sky goal.” The projects are funded by recent grants from the U.S. Department of Energy (DOE) — one from the Biological and Environmental Research (BER) Program and the other from the Advanced Research Project Agency-Energy (ARPA-E). The two DOE programs support the study of microbes and plants for sustainable biofuel production. 208 CALIFORNIA AGRICULTURE • VOLUME 69 , NUMBER 4 Sorghum, in addition to being a staple food grain in much of the world, is promising as a bioenergy crop and as a substitute for corn silage in livestock rations. It is a good candidate for improved drought tolerance in part because it already handles water stress better than many other crops, including its close relative, corn. The grain emerged as a food crop in drought- prone areas of Africa, and existing varieties exhibit a range of traits that help the crop endure periods of scarce water. Peggy Lemaux, a UC ANR Cooperative Extension specialist based at UC Berkeley, is the principal in- vestigator on the 5-year, $12.3 million BER-funded project awarded in September. Using field plots of sorghum at Kearney and West Side RECs, the project will investigate what’s known as the epigenetics of drought tolerance — the ways in which certain genes are activated in response to water stress, Lemaux said. These mechanisms, which allow rapid adjustments to stresses, can change the plant’s physiology to better cope with reduced moisture. The project also will investigate how microbes in the soil may interact with sorghum to enhance its drought tolerance. Compounds produced by microbes may act as signals, touching off epigenetic or other responses that help sorghum plants survive a long dry stretch, Lemaux said. Microbial populations also might enhance delivery of water and nutrients to a sorghum plant’s roots and trigger them to produce en- zymes and plant hormones that influence its growth and yield. Lemaux noted that the BER project takes advan- tage of UC ANR’s institutional structure, partnering campus-based Agricultural Experiment Station (AES) faculty and Cooperative Extension specialists with researchers based at the RECs. The project’s collabo- rators also include a UC Berkeley faculty member in statistics and DOE researchers based at the Joint Genome Institute and the Pacific Northwest National Laboratory (PNNL). It’s a powerful combination of laboratory and field expertise and resources, Lemaux said. “We couldn’t do it without them, and they couldn’t do it without us,” Lemaux said of the collaboration be- tween campus- and REC-based researchers.