Poster: Temperature responses

Abs # 119: Functional genomics of heat stress induced early-programmed seed drying in wheat

Presenter:	Yang, Zhuping , yangz@neo.tamu.edu
Authors	Yang, Zhuping  (A)   Do, Jung H (A)   Gordy, John  (A)   Hays, Dirk B (A)
Affiliations:	(A): Department of Soil and Crop Sciences, Texas A&M University

High temperature during reproductive development is the major problem to wheat production in the Southern Great Plains and to wheat production in many environments worldwide. We have initiated a project to characterize genes involved in the regulation of the heat stress induced early programmed seed desiccation, and seed abortion in heat susceptible genotypes and to determine which gene pathways are modified in heat tolerant genotypes. Efforts have initially focused on building cDNA libraries enriched, through suppressive subtractive hybridization, for genes induced by the heat stress. The selected tissues for library construction included wheat heads isolated from plants subjected to heat stress at 10 days after pollination. A heat tolerant spring wheat cv Halberd, and a susceptible spring wheat cv Len were used as models to define the two adaptive responses to heat stress (heat avoidance (susceptible) and heat tolerance). Over 1920 ESTs have been sequenced for each cultivar so far, which represent an as yet undetermined number of distinct genes. Mining of the database to identify functional categories of genes will be reported for ESTs confirmed to be differentially expressed during heat stress using cDNA macroarrays. The differential expression of key regulatory genes confirmed by Northern analysis and real time RT-PCR to be either up or down regulated following heat stress will also be reported for the tolerant and susceptible cultivar. These genes include many novel genes that may belong to uncharacterized pathways regulating the two unique response strategies to heat stress. The importance of differential gene expression to improved adaptations to heat stress will be discussed.