Comprehensive analysis of the regulatory network of blue-light-regulated conidiation and hydrophobin production in Trichoderma guizhouense

Conidia of Trichoderma guizhouense (Hypocreales, Ascomycota) are frequently applied to the production of biofertilizers and biocontrol agents. Conidiation of some Trichoderma species depends on blue light and the action of different blue light receptors. However, the interplay between different blue-light receptors in light signalling remained elusive. Here, we studied the functions of the blue light receptors BLR1 and ENV1, and the MAP kinase HOG1 in blue light signalling in T. guizhouense. We found that the BLR1 dominates light responses and ENV1 is responsible for photoadaptation. Genome-wide gene expression analyses revealed that 1615 genes, accounting for similar to 13.4% of the genes annotated in the genome, are blue-light regulated in T. guizhouense, and remarkably, these differentially expressed genes (DEGs) including 61 transcription factors. BLR1 and HOG1 are the core components of the light signalling network, which control 79.9% and 73.9% of the DEGs respectively. In addition, the strict regulation of hydrophobin production by the blue light signalling network is impressive. Our study unravels the regulatory network based on the blue light receptors and the MAPK HOG pathway for conidiation, hydrophobin production and other processes in T. guizhouense.

Automated summary

In Trichoderma guizhouense, the blue light receptor BLR1 dominates light responses while ENV1 is responsible for photoadaptation. The core components of the light signaling network, BLR1 and HOG1, control the expression of a large portion of the differentially expressed genes (DEGs). This study reveals a regulatory network based on blue light receptors and the MAPK HOG pathway for various processes in T. guizhouense, including conidiation and hydrophobin production.