title: Mas5, a homologue of bacterial DnaJ, is indispensable for the host infection and environmental adaptation of a filamentous fungal insect pathogen.
abstract: Mas5, a yeast heat shock protein classified to the Hsp40 group, is homologous to bacterial archetype DnaJ but functionally unexplored in filamentous fungi. Here we identify a Mas5 homologue (46.86 kDa) in Beauveria bassiana and show its indispensability for host infection and environmental adaptation of the fungal insect pathogen. The deletion of mas5 caused severe defects in aerial conidiation, conidial germination and submerged blastospore production (mimic to host haemocoel). The deletion mutant lost 100% virulence to Galleria mellonella larvae through normal cuticular penetration (topical inoculation) and 50% through cuticle-bypassing infection (intrahaemocoel injection). It formed no blastospore in vivo after inoculation or only a very few after injection. Its extracellular (cuticle degrading) enzymes and virulence-relating Pr1 proteases were 62% and 32% less active respectively. It became more sensitive to high osmolarity, oxidation, cell-wall perturbation, heat shock and UV-B irradiation. These concurred with reduced contents of intracellular mannitol and trehalose, decreased activities of antioxidant enzymes, impaired cell walls and suppressed transcripts of stress-responsive and virulence-relating genes. All the changes were restored by targeted mas5 complementation. All together, Mas5 is indispensable for the in vitro and in vivo life cycle of B. bassiana by targeting many sets of enzymes/proteins at transcriptional and post-transcriptional levels.
authors.affiliation: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.|Key Laboratory of Tropical Marine Bio-resources and Ecology, RNAM Center for Marine Microbiology, Guangdong Key Laboratory of Marine Material Medical, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, Guangdong, 510301, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
authors.affiliation: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
authors.forename: Sheng-Hua
authors.initials: SH
authors.lastname: Ying
authors.affiliation: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China.
authors.forename: Ming-Guang
authors.initials: MG
authors.lastname: Feng
mesh_terms: D000818:Animals; D052982:Beauveria / Q000472:pathogenicity*; D002473:Cell Wall / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics*; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics*; D007814:Larva / Q000382:microbiology*; D009036:Moths / Q000382:microbiology*; D009997:Osmotic Pressure; D013172:Spores, Fungal / Q000378:metabolism; D014774:Virulence / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D050956:HSP40 Heat-Shock Proteins