Sterol regulatory element-binding proteins mediate intrinsic fungicide tolerance and antagonism in the fungal biocontrol agent Clonostachys rosea IK726

Abstract

Sterol regulatory element-binding proteins (SREBPs) are transcription factors governing various biological processes in fungi, including virulence and fungicide tolerance, by regulating ergosterol biosynthesis and homeostasis. While studied in model fungal species, their role in fungal species used for biocontrol remains elusive. This study delves into the biological and regulatory function of SREBPs in the fungal biocontrol agent (BCA) Clonostachys rosea IK726, with a specific focus on fungicide tolerance and antagonism. Clonostachys rosea genome contains two SREBP coding genes (sre1 and sre2) with distinct characteristics. Deletion of sre1 resulted in mutant strains with pleiotropic phenotypes, including reduced C. rosea growth on medium supplemented with prothioconazole and boscalid fungicides, hypoxia mimicking agent CoCl2 and cell wall stressor SDS, and altered antagonistic abilities against Botrytis cinerea and Rhizoctonia solani. However, Delta sre2 strains showed no significant effect. Consistent with the gene deletion results, overexpression of sre1 in Saccharomyces cerevisiae enhanced tolerance to prothioconazole. The functional differentiation between SRE1 and SRE2 was elucidated by the yeasttwo-hybridization assay, which showed an interaction between SREBP cleavage-activating protein (SCAP) and SRE1 but not between SRE2 and SCAP. Transcriptome analysis of the Delta sre1 strain unveiled SRE1-mediated expression regulation of genes involved in lipid metabolism, respiration, and xenobiotic tolerance. Notably, genes coding for antimicrobial compounds chitinases and polyketide synthases were downregulated, aligning with the altered antagonism phenotype. This study uncovers the role of SREBPs in fungal BCAs, providing insights for C. rosea IK726 application into integrated pest management strategies.

Keywords

Ergosterol; Hypoxia tolerance; Iron homeostasis; Integrated pest management strategies; Lipid metabolism; SREBP; Sterol biosynthesis

Published in

Microbiological Research
2024, volume: 289, article number: 127922
Publisher: ELSEVIER GMBH

SLU Authors

• Piombo, Edoardo

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

• Tzelepis, Georgios

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

• Gustavsson Ruus, Alma

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

• Rafieebanadaki, Vahidehalsadat

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

• Jensen, Dan Funck

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

• Karlsson, Magnus

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

• Dubey, Mukesh

  • Department of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Microbiology

Publication identifier

• DOI: https://doi.org/10.1016/j.micres.2024.127922

Permanent link to this page (URI)

https://res.slu.se/id/publ/133032