Identification of Salt Stress Responsive ESTs From Red Fescue and Perennial Ryegrass Using PCR-Based cDNA Subtraction.

Salt stress adversely affects the growth of plants. The objective of the present study is to identify differentially expressed salt response genes in salt tolerant and sensitive red fescue and perennial ryegrass accessions. The salt tolerant and sensitive red fescue accessions were PI 595057 and PI 632525 respectively. PST 2J15 and Linn were the tolerant and sensitive accessions for perennial ryegrass. The tolerant and sensitive accessions were grown in green house for two months supplemented with half strength Hoaglands solution. Ryegrass and red fescue accessions were treated or untreated with 10000 mgL-1 and 7500 mgL-1 NaCl respectively for a period of two weeks. The leaves  were harvested separately from both species and PCR subtraction was performed using the untreated (control) plants as a driver and the NaCl treated plants as the tester. Four subtraction libraries will be constructed from the leaf tissues of tolerant and sensitive red fescue and ryegrass accessions. The libraries will be sequenced and the sequences will be compared to known genes in Genbank. The two-week salt treatment is expected to be more effective than 24-hour treatment in up-regulating genes associated with sodium toxicity rather than osmotic stress.