Integrative analysis of transcriptome and yeast screening system identified heat stress-responding genes in ryegrass

Heat stress threatens plant survival and productivity as global warming continues. Thus, it is urgent to understand heat tolerance genetically, especially in cool-season plants. Herein, ryegrass, a cool season grass, was subjected to two heat-temperature treatments (acquired and basal thermotolerances), followed by heat response gene identification using a transcriptome and yeast screening system. A total of 2730 and 8087 differentially expressed genes (DEGs) were identified by transcriptome in AT (acquired thermotolerance) and BT (basal thermotolerance) treatments, while 124 potential heat tolerance genes were identified by yeast screening. This study is the first to reveal the continuous changes in gene expression levels in ryegrass at the whole-genome level during the process of high temperature response. Our findings indicate that, in both the AT and BT experiments, there was a general inhibition of photosynthesis-related gene expression levels over time, whereas the expression levels of endoplasmic reticulum protein processing-related genes were primarily induced. The analysis of the yeast screening system indicated that the ryegrass ribosomal protein genes may play an essential role in high temperature response. Our study identified some genes and proteins related to heat tolerance in ryegrass and provided new and crucial clues to understand the resistance of ryegrass to heat stress.