SALT STRESS RESPONSIVE TESTS FROM PERENNIAL RYEGRASS AND RED FESCUE

摘要

Soil salinity is a major abiotic stress factor responsible for significant reduction in plant yield,growth and development.There is a continued need for the development of salinity tolerant turfgrass cultivars,as effluent water is increasingly used for turfgrass irrigation.Perennial ryegrass (Lolium perenne L.) and creeping red fescue (Festuca rubra L.ssp.rubra) are economically important cool-season turf species.The aim of the current study was to identify candidate genes differentially up regulated under salt stress in these species using PCR based cDNA suppression subtractive hybridization (SSH).The L.perenne accessions were PST 2J15(T) (tolerant) and Linn(S) (sensitive) and the F.rubra accessions were PI 595057(T) (tolerant) and PI 632525(S) (susceptible).More than four-fold fewer transcripts were identified in salt sensitive accessions than in salt tolerant accessions.Forty seven transcripts were identified in PI 632525(S) and none were identified in Linn(S),as compared to 199 and 226 for PI 595057(T) and PST 2J15(T) respectively.The PST2J15(T) library was rich in transcripts of genes associated with synthesis of compatible solutes and dehydration tolerance,but contained no transcripts for genes associated with selective ion transport.This suggests that salt tolerance in perennial ryegrass relies on control of osmotic stress.In contrast,while genes for compatible solutes were upregulated in the susceptible red fescue,the PI 595057(T) library contained many transcripts for genes associated with selective ion transport and no transcripts for genes associated with compatible solute synthesis or dehydration tolerance.Thus salt tolerance in red fescue appears to rely on the ability to selectively take up potassium while excluding sodium.