A functional genomics approach for identification of heat tolerance genes in tall fescue

Tall fescue (Festuca arundinacea Schreb.) is a major cool season forage and turf grass species around the world. Heat stress is one of the limiting factors for forage production and turf management of this grass species. This research uses functional genomics approaches for discovering the molecular basis of heat tolerance in tall fescue genotypes. To identify genes expressed during heat stress, a heat stressed shoot cDNA library was constructed from popular tall fescue cultivar Kentucky 31 with shoot tissues collected at five time points (12 - 78 hrs) after exposure to high heat (42 - 44degreesC) in a growth chamber. High-throughput sequencing of the cDNA clones is underway for generating 5,000 ESTs. The ESTs related to heat-stress will be identified from this cDNA library. Heat-tolerance related genes are cloned by using suppression subtractive hybridization (SSH) between heat tolerant and heat sensitive cultivars. Heat tolerance-related genes isolated by SSH will be combined with genes cloned from shoot cDNA library to generate a cDNA microarray to study the expression profiles of tall fescue cultivars with different responses to the heat stress. Heat tolerance genes identified from this project will be useful for development of tall fescue cultivars adapted to high heat environments.