Transcriptional responses of Metarhizium pingshaense blastospores after UV-B irradiation

Front Microbiol. 2024 Dec 5:15:1507931. doi: 10.3389/fmicb.2024.1507931. eCollection 2024.

Abstract

Metarhizium is widely known for its role as an arthropod biocontrol agent and plant bioinoculant. By using mass-production industrial methods, it is possible to produce large amounts of fungal single-celled propagules (including blastospores) to be applied in the field. However, in the environment, the solar ultraviolet components (particularly UV-B) can harm the fungus, negatively impacting its pathogenicity toward the arthropod pest. The present study is the first to use comparative genome-wide transcriptome analyses to unveil changes in gene expression between Metarhizium pingshaense blastospores exposed or not to UV-B. Relative blastospores culturability was calculated 72 h after UV-B exposure and exhibited 100% culturability. In total, 6.57% (n = 728) out of 11,076 predicted genes in M. pingshaense were differentially expressed after UV-B exposure: 320 genes (44%; 320/728) were upregulated and 408 (56%; 408/720) were downregulated in the UV-B exposed blastospores. Results unveiled differentially expressed gene sets related to fungal virulence, production of secondary metabolites, and DNA repair associated with UV damage; genes related to virulence factors were downregulated, and genes associated with nucleotide excision repair were upregulated. These findings illustrate critical aspects of Metarhizium blastospores strategies to overcome UV-B damage and survive solar radiation exposures in insulated fields.

Keywords: RNA-seq; bioinputs; entomopathogenic fungi; insect control; tolerance to UV-B.

Grants and funding

The authors declare that financial support was received for the research, authorship, and/or publication of this article. This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior -Brasil (CAPES) - Finance Code 001, providing Ph.D. scholarship for LC and TC. The Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) of Brazil provided scholar ships for AC, EM, and VSB. Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) provided scholarship for JF. The research was supported by grants from FAPERJ (E-26/201.389/2021), CNPq/INCT Molecular Entomology (465678/2014-9), and CNPq/INCT Innovative Bioinputs (406803/2022-6).