Transcriptome Analysis Revealed That Cell Wall Regulatory Pathways Are Involved in the Tolerance of Pleurotus ostreatus Mycelia to Different Heat Stresses
Ludan Hou, Jingyi Wang, Tonglou Li, Baosheng Zhang, Kexing Yan, Zehua Zhang, Xueran Geng, Mingchang Chang, Junlong Meng
Abstract
Pleurotus ostreatus is the third largest cultivated species in China’s edible mushroom industry; however, its agricultural cultivation method is easily affected by high-temperature environments. To understand the response mechanism of mycelia to heat stress, the mycelia of P. ostreatus, which had been grown at 28 °C for 4 days, were subjected to heat stress at 32 °C and 36 °C for 2 days, followed by RNA-seq analysis. These results indicate that, under heat stress, mycelial growth was significantly inhibited, the cell membrane was disrupted, the cell walls became thicker, and chitinase and β-1,3-glucanase activities decreased. Transcriptome analysis revealed 2118 differentially expressed genes (DEGs) under 36 °C heat stress, and 458 DEGs were identified under 32 °C heat stress. A total of 328 DEGs were upregulated or downregulated under heat stress at 36 °C and 32 °C. The functional enrichment analysis of these genes revealed significant enrichment in genes related to hydrogen peroxide metabolism, oxidoreductase activity, ATP hydrolysis, and cell wall structure composition. There was a total of 80 DEGs specific to heat stress at 32 °C, and they were significantly enriched in catalase activity, the cell wall, the aminoglycan catabolic process, and oxidoreductase activity. However, 817 DEGs specific to heat stress at 36 °C were significantly enriched in the cell wall, integral components of the membrane, and oxidoreductase activity. The identification of cell wall-related genes revealed that hydrophobic proteins, Cerato plateau proteins, laccases, and glycoside hydrolases may respond to stress. The results of qRT-PCR for cell wall-related genes are consistent with the RNA-seq data. This study revealed several potential candidate genes for high-temperature thermal response, laying the foundation for the study of the thermal response mechanism of P. ostreatus.