MaPom1, a Dual-Specificity Tyrosine Phosphorylation-Regulated Kinase, Positively Regulates Thermal and UV-B Tolerance in Metarhizium acridum

Abstract

Fungi play irreplaceable roles in the functioning of natural ecosystems, but global warming poses a significant threat to them. However, the mechanisms underlying fungal tolerance to thermal and UV-B stresses remain largely unknown. Dual-specificity tyrosine phosphorylation-regulated kinase (DYRK) Pom1 is crucial for fungal growth, conidiation, and virulence. However, its role in stress tolerance within kingdom fungi has not been explored. In this study, we analyzed the function of MaPom1 (a Pom1 homologous gene) in the entomopathogenic fungus Metarhizium acridum and its regulatory roles in stress tolerance. Conidial thermal and UV-B tolerance significantly decreased in the MaPom1 disruption strain (ΔMaPom1), whereas conidial yield and virulence were unaffected. RNA-Seq analysis indicated that the differentially expressed genes (DEGs) were primarily related to amino sugar, nucleotide sugar metabolism, cell wall components, growth and development, and stress response pathways. Under heat shock treatment, the expression levels of heat shock protein genes decreased significantly, leading to reduced thermotolerance. Moreover, under UV-B treatment, MaPom1 expression and the enzyme activity significantly changed, indicating its involvement in regulating UV-B tolerance. The percentage of nuclear damage in ΔMaPom1 under UV-B treatment was higher than that in the wild-type strain (WT) and the complementary strain (CP). Additionally, the transcription levels of DNA damage-related genes significantly decreased, whereas those of several genes involved in the DNA damage repair response increased significantly. Overall, MaPom1 contributed to thermal and UV-B tolerance by regulating the expression of heat shock protein genes and DNA damage repair genes.