Transcription Activator Swi6 Interacts with Mbp1 in MluI Cell Cycle Box-Binding Complex and Regulates Hyphal Differentiation and Virulence in Beauveria bassiana

Abstract

Mbp1 protein acts as a DNA-binding protein in MluI cell cycle box-binding complex (MBF) and plays an essential role in filamentous myco-pathogen Beauveria bassiana.In the current study, BbSwi6 (a homologue of yeast Swi6) was functionally characterized in B.bassiana. Both BbSwi6 and BbMbp1 localize in the nucleus and display a direct interaction relationship which is indicated by a yeast two-hybrid assay. BbSwi6 significantly contributes to hyphal growth, asexual sporulation and virulence. On the aerial surface, ΔBbSwi6 grew slower on various nutrients and displayed abnormal conidia-producing structures, which hardly produced conidia. In liquid media, BbSwi6 loss led to 90% reduction in blastospore yield. Finally, the virulence of the ΔBbSwi6 mutant was modestly weakened with a reduction of 20% in median lethal time. Comparative transcriptomics revealed that BbSwi6 mediated different transcriptomes during fungal development into conidia and blastospores. Notably, under the indicated condition, the BbSwi6-mediated transcriptome significantly differed to that mediated by BbMbp1. Our results demonstrate that, in addition to their roles as the interactive components in MBF, BbSwi6 and BbMbp1 mediate divergent genetic pathways during morphological transitions in B. bassiana.

The Entomopathogenic Fungus Beauveria bassiana Employs Autophagy as a Persistence and Recovery Mechanism during Conidial Dormancy

“…Autophagosome ultrastructures were examined with TEM ( 24 ), while autophagic flux was measured with the fluorescent reporter method ( 15 ). Specifically, the coding sequences of BbAtg8 and BbAtg8 T were amplified and then cloned into vectors to confer chlorsulfuron resistance ( 50 ). The hybrid gene was transformed into the Δ Bbatg8 strain, and the functioning of BbAtg8 T in selective autophagy was determined by analyzing pexophagy and mitophagy, as previously described ( 15 ).…”

Proteomic and Phosphoryproteomic Investigations Reveal that Autophagy-Related Protein 1, a Protein Kinase for Autophagy Initiation, Synchronously Deploys Phosphoregulation on the Ubiquitin-Like Conjugation System in the Mycopathogen Beauveria bassiana

“…The obtained fragments were cloned into pTMTB, generating the plasmid p0380-TEF-MCS-YC-bar (p0380TM-YC-B). YN was amplified from pUC35S-cYFP/N (Biogle Co.) with primer pair P37/P38 and integrated into plasmid p0380-TEF-sur ( 57 ), generating p0380-TEF-MCS-YN-sur (p0380TM-YN-S). To test the in vivo protein interaction, the primer pairs P39/P40 and P41/P42 were used to amplified BbATG1 and BbATG3 , respectively.…”

SterylAcetyl Hydrolase 1 (BbSay1) Links Lipid Homeostasis to Conidiogenesis and Virulence in the Entomopathogenic Fungus Beauveria bassiana

“…The indicated strain was cultured on SDAY plates at 25 °C for 7 days, and the resultant conidia were suspended in a 0.02% Tween-80 solution. All phenotypes were compared among the wild-type, Δ Bbsay1, and complementation mutant strains with three parallel experiments [ 7 , 20 ].…”