Differential roles of Scj1 and Djp1, two DnaJ homologs, in virulence, cell wall integrity, and multi-stress tolerance of Beauveria bassiana
摘要
Enhancing environmental adaptability and virulence is crucial for improving the biocontrol potential of Beauveria bassiana, a filamentous entomopathogen widely employed for biological pest control in agriculture and forestry. It was reported that DnaJ proteins play important and distinct roles in fungal growth, conidiation, environmental adaptation, and virulence. However, apart from Mas5 and Mdj1, the functions of other DnaJ proteins in B. bassiana remain largely unexplored. In this study, the functions of two DnaJ homologs of Scj1 and Djp1 in B. bassiana were characterized through multi-phenotype analyses under normal and stressful conditions. Deletion of scj1 or djp1 led to significant yet distinct changes in fungal growth, hyphal and conidial thermotolerance, nutrient utilization, cell wall integrity, antioxidant capacity, and tolerance to the fungicide carbendazim and UV-B radiation. Moreover, Δscj1 exhibited delayed conidial germination under normal condition, while Δdjp1 showed reduced fungal sensitivity to NaCl. Furthermore, the median lethal time (LT50) increased by 26.06% in Δscj1 and 37.58% in Δdjp1 in bioassays against Galleria mellonella larvae infected via normal cuticle penetration, compared to the wild-type strain and complementation mutants. The findings provide a comprehensive insight into vital roles of scj1 and djp1 in asexual development, environmental adaptation, and virulence of B. bassiana, providing new insights for enhancing its efficacy as a biocontrol agent.