Plant & Animal Genomes XIV Conference

January 14-18, 2006
Town & Country Convention Center
San Diego, CA

Using Sorghum'S Integrated Genome Platform To Study The Genetic Basis Of Drought Tolerance

John E Mullet¹ , Patricia E Klein¹ , Robert R Klein² , William L Rooney¹ , David R Jordan⁴ , Andrew K Borrell⁴ , Darrell T Rosenow¹ , Henry Nguyen⁵ , Lee H Pratt³ , Marie-Michele Cordonnier-Pratt³ , David M Stelly¹ , James H Price¹ , Daryl T Morishige¹ , Monica A Menz¹ , Christina D Buchanan¹ , Karen R Harris¹ , Brock D Weers¹ , Jeong-Soon Kim¹ , Sanghyun Lim¹ , Bin Zhou¹

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

²  USDA-ARS Southern Plains Agricultural Research Center, College Station, Texas, 77845

³  Department of Plant Biology, University of Georgia, Athens, Georgia, 30602

⁴  Department of Primary Industries, Hermitage Research Station, Warwick, Queensland, Australia, 4370

⁵  Department of Agronomy, University of Missouri, Columbia, MO, 65211

Sorghum bicolor is well adapted to drought prone and nutrient limited environments. Sorghum is a useful genome reference for C4 grass species because it has a relatively small genome (~800Mbp), high degree of colinearity with the rice and maize genomes, facile genetics, and an extensive and diverse germplasm collection. Over the past ~8 years, a comprehensive set of genome and genetic resources have been developed for sorghum. These resources include a high density genetic and physical map that is aligned to the rice and maize genomes, a comprehensive understanding of sorghum chromosome architecture based on BAC-FISH, a deep collection of cDNA sequences, and information on the diversity of U.S. sorghum breeding materials. The sorghum genome resources are being used to map and clone genes that control flowering time, drought tolerance, fertility restoration, nutrient acquisition and other traits. An update on map-based analysis of sorghum's 'stay green' drought tolerance mechanism will be presented. In addition, sorghum genes involved in responses to osmotic stress have been identified using microarrays containing ~22,000 gene sequences. This information, together with RT-PCR analysis of transcript levels, and phylogenetic analysis is helping to elucidate the biochemical pathways and gene regulatory networks that mediate responses to osmotic stress in sorghum. Recently, sorghum genotypes have been found to vary in how they modulate drought and ABA responsive genes. The extent and molecular basis of variation in gene expression in two sorghum genotypes will be described.