Morphological and Transcriptomic Response Mediated by Heat Stress in Pleurotus Pulmonarius

Heat stress, one of the major abiotic stresses, affected the growth, fruit body formation and survival of edible mushrooms. Morphological analysis of the Pleurotus pulmonarius Jinxiu displayed that heat stress significantly triggered the inhibited growth of mycelium, weak antifungal activity, yellow water exudation and reduced yield. In order to investigate the underlying mechanism regulating the heat stress response of P. pulmonarius, we analyzed transcriptomic alterations resulting in response to heat stress using high-throughput RNA sequencing of P. pulmonarius strain Jinxiu under heat stress and normal conditions. Totally, we obtained 1,955 deferentially expressed genes. We observed that P. pulmonarius regulated the expression of genes involved in protein processing in endoplasmic reticulum, glycerophospholipid metabolism and glycerolipid metabolism, glutathione metabolism, energy metabolism and carbohydrate metabolism, and transcription factor to response to heat stress. We found that heat shock protein genes could contribute to defense against heat damage and fungal infection. The down-expression of steroid biosynthesis genes in mycelium treated with heat stress might result in weaken antifungal activity and fruit body formation with consequent of fungal infection and reduced yield. This study provided a valuable database for identifying candidate genes and pathways in response to heat stress. Furthermore, it laid the foundation for molecular breeding of new P. pulmonarius strains with improvement of heat-tolerant characters and yield.