Dual regulatory roles of the zinc cluster transcription factor MrFTRP1 in development, stress tolerance, and virulence of Metarhizium robertsii.
TL;DR
It is demonstrated that MrFTRP1 exerts a dual-regulatory functioning as a positive regulator of conidiation and pathogenesis but a negative regulator of environmental stress tolerance, which expands the understanding of the regulatory diversity within the C6 TF family and identifies him as a promising target for the genetic improvement of mycoinsecticides.
Abstract
The entomopathogenic fungus Metarhizium robertsii shows significant potential as a multifunctional biocontrol agent. The Zn(II)₂Cys₆ (C6) transcription factors (TFs) family is the largest class of transcription factors in M. robertsii, yet their functions are generally underexplored. In this study, we functionally characterized a putative C6 TF, designated MrFTRP1. Deletion of Mrftrp1 reduced conidial yield, which correlated with the downregulation of key central developmental regulators, including brlA, abaA, and wetA. Moreover, ΔMrftrp1 exhibited attenuated virulence against Galleria mellonella, a defect attributable to reduced conidial hydrophobicity, impaired adhesion, compromised appressorium formation, and decreased proliferation of yeast-like hyphal bodies in vivo. Conversely, the loss of Mrftrp1 significantly enhanced conidial tolerance to heat shock and UV-B irradiation, accompanied by the upregulation of stress-response and DNA repair-related genes. Collectively, our findings demonstrated that MrFTRP1 exerts a dual-regulatory functioning as a positive regulator of conidiation and pathogenesis but a negative regulator of environmental stress tolerance. This dual-functional role expands our understanding of the regulatory diversity within the C6 TF family and identifies MrFTRP1 as a promising target for the genetic improvement of mycoinsecticides.