Identification of Candidate Genes Associated with Physiological Traits for Heat Stress Tolerance in Fine Fescue.

Heat stress is among the most prominent and aggravating environmental factors for cool-season turfgrass species. The objective of this study was to identify candidate genes that are associated with heat stress tolerance and potential PCR-based markers linked to physiological traits for heat tolerance in fine fescue. Phenotypic variations of 26 fine fescue cultivars, including hard fescue, chewing fescue, strong fescue, sheep fescue and slender fescue, were tested upon heat stress of 35/30 °C in a growth chamber. Physiological parameters, such as leaf chlorophyll content, electrolyte leakage and photochemical efficiency, confirmed good separation upon 35 days of heat stress. Candidate genes that are related to plant photosynthesis, energy, cell structure, defense, oxidative response further confirmed their differential expression levels under heat stress in different cultivars. PCR-based markers were assessed based on various molecular maps from meadow fescue and tall fescue. The candidate genes and potential PCR-based markers identified in this study may be implemented in future studies to facilitate marker-assisted molecular breeding for heat-tolerant cultivars or to elucidate possible mechanisms regulating heat tolerance in fine fescue.