title: Miro GTPase controls mitochondrial behavior affecting stress tolerance and virulence of a fungal insect pathogen.
abstract: Miro homologues are small mitochondrial Rho GTPases belonging to the Ras superfamily across organisms and are generally unexplored in filamentous fungi. Here we identified a Miro orthologue (bMiro) in Beauveria bassiana, a filamentous fungal insect pathogen as a classic biological control agent of insect pests. This orthologue was proven to anchor on mitochondrial outer membrane in a manner depending completely upon a short C-terminal transmembrane domain. As a result of bmiro deletion, mitochondria in hyphal cells were largely aggregated, and their mass and mobility were reduced, accompanied with a remarkable decrease in ATP content but little change in mitochondrial morphology. The deletion mutant became 42%, 37%, 19% and 10% more tolerant to Ca(2+), Mn(2+), Zn(2+) and Mg(2+) than wild-type, respectively, during cultivation in a minimal medium under normal conditions. The deletion mutant also showed mild defects in conidial germination, vegetative growth, thermotolerance, UV-B resistance and virulence despite null response to oxidative and osmotic stresses. All these phenotypic changes were restored by targeted gene complementation. Our results indicate that bMiro can control mitochondrial distribution and movement required for the transport of ATP-form energy and metal ions and contributes significantly to the fungal potential against insect pests through the control.
authors.affiliation: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Guan
authors.affiliation: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China.
authors.forename: Ding-Yi
authors.initials: DY
authors.lastname: Wang
authors.affiliation: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China.
authors.forename: Sheng-Hua
authors.initials: SH
authors.lastname: Ying
authors.affiliation: Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China. Electronic address: mgfeng@zju.edu.cn.
authors.forename: Ming-Guang
authors.initials: MG
authors.lastname: Feng
mesh_terms: D000818:Animals; D052982:Beauveria / Q000201:enzymology / Q000235:genetics*; D002473:Cell Wall / Q000201:enzymology / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D025301:Hyphae / Q000201:enzymology / Q000235:genetics; D007313:Insecta / Q000382:microbiology*; D008928:Mitochondria / Q000201:enzymology / Q000235:genetics*; D009997:Osmotic Pressure; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D013172:Spores, Fungal / Q000254:growth & development; D020741:rho GTP-Binding Proteins / Q000235:genetics*
chemical_list: C120472:GEM1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D020741:rho GTP-Binding Proteins
keywords: Beauveria bassiana; Biological control potential; Miro GTPase; Mitochondrial distribution; Mitochondrial mobility