{"title":"The putative Rho guanine nucleotide exchange factor GerA in Aspergillus flavus regulates growth, development, and aflatoxin synthesis","authors":"Jia Xu , Junhe Ren , Yanyan Zhang, Zhuoyu Han, Qing Kong","doi":"10.1016/j.ijfoodmicro.2025.111302","DOIUrl":null,"url":null,"abstract":"<div><div><em>Aspergillus flavus</em> is a saprophytic fungus that infects seed crops before and after harvest, producing potent carcinogens known as aflatoxins. Consequently, the urgent need arises to develop control strategies to mitigate the adverse effects associated with <em>A. flavus</em>. The Ras homologue family member GTPases (Rho GTPases) play a crucial role in regulating the developmental and pathogenic processes of filamentous fungi by controlling various signal transduction pathways. Rho guanine nucleotide exchange factors (GEFs) activate Rho GTPases and regulate their conformational conversion from GDP to GTP. In a previous study, a Rho GEF GerA that is closely regulated by the global regulator VeA under different culture conditions was identified by chromatin immunoprecipitation and sequencing (ChIP-seq), which contains a characteristic Dbl homology (DH) domain. GerA exhibits a high degree of conservation within <em>Aspergillus</em> species but lacks homologues in <em>Saccharomyces cerevisiae</em>. The generation of the Δ<em>gerA</em> mutant using CRISPR/Cas9 gene editing tools significantly impacted the synthesis of AFs, reproductive processes, and pathogenicity in <em>A. flavus</em>. Notably, the Δ<em>gerA</em> mutant exhibited polarity loss and impaired septation. Combined with yeast two-hybrid analysis, there is speculation that GerA may function as a Rho4 GEF. The significant involvement of <em>gerA</em> in the morphological development and secondary metabolism of <em>A. flavus</em> highlights its potential as a target for control measures. Moreover, this study establishes a basis for further investigating the roles of other Rho GEFs in filamentous fungi.</div></div>","PeriodicalId":14095,"journal":{"name":"International journal of food microbiology","volume":"441 ","pages":"Article 111302"},"PeriodicalIF":5.0000,"publicationDate":"2025-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International journal of food microbiology","FirstCategoryId":"97","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0168160525002478","RegionNum":1,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"FOOD SCIENCE & TECHNOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Aspergillus flavus is a saprophytic fungus that infects seed crops before and after harvest, producing potent carcinogens known as aflatoxins. Consequently, the urgent need arises to develop control strategies to mitigate the adverse effects associated with A. flavus. The Ras homologue family member GTPases (Rho GTPases) play a crucial role in regulating the developmental and pathogenic processes of filamentous fungi by controlling various signal transduction pathways. Rho guanine nucleotide exchange factors (GEFs) activate Rho GTPases and regulate their conformational conversion from GDP to GTP. In a previous study, a Rho GEF GerA that is closely regulated by the global regulator VeA under different culture conditions was identified by chromatin immunoprecipitation and sequencing (ChIP-seq), which contains a characteristic Dbl homology (DH) domain. GerA exhibits a high degree of conservation within Aspergillus species but lacks homologues in Saccharomyces cerevisiae. The generation of the ΔgerA mutant using CRISPR/Cas9 gene editing tools significantly impacted the synthesis of AFs, reproductive processes, and pathogenicity in A. flavus. Notably, the ΔgerA mutant exhibited polarity loss and impaired septation. Combined with yeast two-hybrid analysis, there is speculation that GerA may function as a Rho4 GEF. The significant involvement of gerA in the morphological development and secondary metabolism of A. flavus highlights its potential as a target for control measures. Moreover, this study establishes a basis for further investigating the roles of other Rho GEFs in filamentous fungi.
期刊介绍:
The International Journal of Food Microbiology publishes papers dealing with all aspects of food microbiology. Articles must present information that is novel, has high impact and interest, and is of high scientific quality. They should provide scientific or technological advancement in the specific field of interest of the journal and enhance its strong international reputation. Preliminary or confirmatory results as well as contributions not strictly related to food microbiology will not be considered for publication.