The Two Sexually Compatible Monokaryons from a Heterokaryotic <em>Lentinula edodes </em>Strain Respond Differently to Heat Stress

A comprehensive understanding of the mechanisms underlying how Lentinula edodes handles heat stress (HS) is crucial for the development of superior HS-resistant strains. However, the mechanism by which the two sexually compatible haploid nuclei respond to heat stress remains largely unknown. Here, we examined the nuclei-specific (SP3 and SP30) HS-resistant mechanisms using integrated metabolomic and transcriptomic analysis. Results showed HS elicited the boost of ROS and hampered the mycelium growth for both monokaryons. Metabolome and transcriptome data demonstrated that the two sexually compatible monokaryons responded differently to HS. For SP3, the differentially expressed genes were significantly enriched in MAPK signaling, cell cycle and sugar metabolism, whereas those for SP30 were enriched in glyoxylate and dicarboxylate metabolism, and protein processing. The differentially accumulated metabolites of both strains were enriched in the glycerophospholipid metabolism, alpha-linolenic acid metabolism, biosynthesis of cofactors, etc, but with different regulatory modes. The enriched KEGG pathways for SP3 mostly tend to be down-regulated, whereas those in SP30 showed a contrary trend. The genes in MAPK signaling pathway might be associated with the glycerophospholipid metabolism in SP3, but not in SP30. Omics-integration analysis depicted distinguishable regulatory networks and discovered totally different hub genes of the two strains. Our findings revealed for the first time that the two sexually compatible nuclei responded to HS with different mechanisms and provided candidate metabolites, responsive genes and regulatory pathways for further experimental validation.