Association of Candidate Genes with Salinity Tolerance in Perennial Ryegrass.

Salinity stress has become a more significant problem in perennial grass management in many areas. Perennial Ryegrass (Lolium perenne L.) is an important turf and forage grass in temperate regions around the world, but growth and production of this species is threatened by salinity. Understanding physiological, molecular and genetic basis of salinity tolerance is important for developing salinity-tolerant grass germplasm and improving salinity tolerance using effective management practices. The objective of this study was to identify genes-trait association for salinity tolerance in perennial ryegrass. A hundred ninety-two diverse perennial ryegrass accessions were screened for salinity tolerance under 300 mM NaCl for 10 days. Among accessions, plant height ranged from 8.8 cm to 18 cm, leaf dry weight ranged from 0.05 g to 0.38 g and leaf water content ranged from 53.6% to 81.9%. We cloned 3 HKT family members and named LpHKT1;4, LpHKT1;5 and LpHKT2;1, respectively. HKT1 could transport Na⁺ only, while the function of HKT2 is for uptake and transport both K⁺ and Na⁺. Associations of these genes with phenotypic traits are being analyzed. Further work is to verify the biological functions of these three HKT family members using genetic transformation. Our results will provide insights into molecular adaptation of perennial ryegrass to salinity stress.