Different contributions of the peroxisomal import protein Pex5 and Pex7 to development, stress response and virulence of insect fungal pathogen Beauveria bassiana

Abstract

Aims Peroxins Pex5 and Pex7 belong to the peroxisomal import machinery and recognize proteins containing peroxisomal targeting signal (PTS) type 1 and type 2, respectively. This study seeks to characterize these two peroxins in the entomopathogenic fungus Beauveria bassiana. Methods and Results The orthologs of Pex5 and Pex7 in B. bassiana (BbPex5 and BbPex7) were functionally analyzed via protein localization and gene disruption. BbPex5 and BbPex7 were associated with peroxisome and specifically required for PTS1 and PTS2 pathways, respectively, which were demonstrated to be involved in development, tolerance to oxidative stress and virulence. ΔBbPex5 mutant displayed additionally defectives that were undetected in ΔBbPex7 in vegetative growth and resistance to osmotic and cell wall‐perturbing stresses. Notably, Woronin body major protein Hex1 with PTS1 linked this organelle to the development and virulence of B. bassiana, which indicates that Woronin body is associated with the roles of PTS1 pathway. Conclusion Both PTS1 and PTS2 pathways are involved in broad physiological process, and the PTS1 pathway acts as a main peroxisomal import pathway. Significance and Impact of the Study This study shows the functional divergence of different peroxins and improves our understanding of organellar physiology involved in biocontrol potential of the entomopathogenic fungi.

Peroxins in Peroxisomal Receptor Export System Contribute to Development, Stress Response, and Virulence of Insect Pathogenic Fungus Beauveria bassiana

“…Phenotypic assays were conducted for the WT, gene disruption, and complemented mutant strains as described previously [ 11 ]. Each assay was repeated three times.…”

“…Subcellular localizations of BbPex1, BbPex6, and BbPex26 were determined as described previously [ 11 ]. All primers are shown in Table S1 .…”

“…In filamentous fungi, peroxisomes have important roles in secondary metabolism [ 7 ], development [ 8 ], and pathogenicity [ 9 ]. Similarly, peroxisomes are involved in fatty-acid assimilation, stress response, development, and virulence in B. bassiana [ 10 , 11 ]. Our previous study showed the functional divergence of different peroxins and highlighted the essential roles of peroxisomes involved in biocontrol potential of the entomopathogenic fungi.…”

“…In B. bassiana , Woronin bodies are important for asexual development under aerobic and submerged conditions, which is critical for fungal virulence and potential as a biocontrol agent. The major protein of Woronin bodies (Hex1) is translocated into the peroxisome through the PTS1 pathway [ 11 ]. However, more investigations are still needed to reveal various functions of three components of the PTS receptor exporting complex in filamentous fungi.…”

Phospholipase C (AoPLC2) regulates mycelial development, trap morphogenesis, and pathogenicity of the nematode-trapping fungus Arthrobotrys oligospora

“…The fungal strains were inoculated on TG medium alone (control) or TG medium supplemented with chemical stressors, including cell wall-interfering agents (40, 60, and 80 μg ml −1 Congo red: 0.01%, 0.02%, and 0.03% SDS), oxidants (5, 10, and 15 mmol L −1 H 2 O 2 ; 0.01, 0.02, and 0.03 mmol L −1 menadione), and osmotic agents (0.1, 0.2, and 0.3 mmol L −1 NaCl; 0.25, 0.5, and 0.75 mmol L −1 sorbitol), and cultured for 7 days at 28°C. Colonial diameters were determined after 7-day incubation, and the relative growth inhibition (RGI) values of the fungal colonies under stress conditions were calculated as previously described (Liu et al, 2017;Pang et al, 2021).…”