Plant & Animal Genomes XVII Conference

January 10-14, 2009
Town & Country Convention Center
San Diego, CA

Molecular Analysis Of Sorghum Drought Tolerance Mechanisms

John Mullet¹ , Brock Weers¹ , Andrew Borrell² , David Jordan² , Patricia Klein¹ , William Rooney¹ , Daryl Morishige¹

¹  Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, Texas 77843

²  Department of Primary Industries, Queensland, Australia

Sorghum bicolor is well adapted to water limited environments. The molecular, biochemical, and physiological basis of this adaptation is being investigated through field physiological studies, QTL mapping, analysis of gene expression, eQTL analysis, and phylogenetic analysis. Specific sorghum genotypes express post-flowering drought responses such as the ‘stay-green’ trait that allow these genotypes to remain functional longer under terminal drought conditions. A large number of QTL that modulate the stay-green trait have been identified and an update on the physiological basis of one of these QTL will be presented. Sorghum genotypes also vary in vegetative phase drought tolerance. Drought stress during this phase of development increases the expression of a large number of genes including many ABA responsive genes. The ABA inducible genes encode proteins that participate in pathways involved in osmotic adjustment, transport, metabolism, and pathways known to help protect tissues from damage associated with water deficit. The expression of ABA responsive genes was found to vary among sorghum genotypes. For several genes, eQTL and cis-regulatory element analysis was utilized to understand the genetic and biochemical basis of the observed variation in gene expression. The response of bioenergy sorghum to long periods of water deficit during the growing season will also be described.