{"title":"Key sugar transporters drive development and pathogenicity in <i>Aspergillus flavus</i>.","authors":"Raheela Yasin, Sayed Usman, Qijian Qin, Xiufang Gong, Bin Wang, Linqi Wang, Cheng Jin, Wenxia Fang","doi":"10.3389/fcimb.2025.1661799","DOIUrl":null,"url":null,"abstract":"<p><p><i>Aspergillus flavus</i> is a ubiquitous filamentous fungus that poses significant threats as both a causative agent of invasive aspergillosis and a major source of crop contamination due to production of aflatoxin B1 (AFB1). Sugars are essential for fungal metabolism, cell wall biosynthesis, and virulence, yet sugar transporters (STPs) in <i>A. flavus</i> remain largely uncharacterized. In this study, we systematically investigated three putative STP genes (<i>G4B84_001982</i>, <i>G4B84_005374</i>, and <i>G4B84_009351</i>) by comprehensive functional characterization of gene deletion mutants. Growth assays revealed that <i>G4B84_001982</i> and <i>G4B84_005374</i> mediate uptake of diverse sugar substrates, while <i>G4B84_009351</i> appeared to be non-essential under tested conditions. Heterologous expressions in the hexose transport-deficient <i>Saccharomyces cerevisiae</i> strain confirmed their sugar transporter activity. Phenotypic analysis revealed that the Δ<i>1982</i> and Δ<i>5374</i> mutants showed pleiotropic defects, including impaired growth, reduced sporulation, delayed germination, increased sensitivity to cell wall stressors, and completely abolished sclerotium formation. Pathogenicity assays demonstrated that the two mutants exhibited attenuated virulence in both plants (crop seeds) and animal (<i>Galleria mellonella</i>) infection model. Our findings highlight the essential of two STPs in <i>A. flavus</i> development, stress tolerance, and pathogenicity, offering insights into sugar-mediated pathogenicity in this economically and medically important fungus.</p>","PeriodicalId":12458,"journal":{"name":"Frontiers in Cellular and Infection Microbiology","volume":"15 ","pages":"1661799"},"PeriodicalIF":4.8000,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12450973/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Frontiers in Cellular and Infection Microbiology","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.3389/fcimb.2025.1661799","RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2025/1/1 0:00:00","PubModel":"eCollection","JCR":"Q2","JCRName":"IMMUNOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Aspergillus flavus is a ubiquitous filamentous fungus that poses significant threats as both a causative agent of invasive aspergillosis and a major source of crop contamination due to production of aflatoxin B1 (AFB1). Sugars are essential for fungal metabolism, cell wall biosynthesis, and virulence, yet sugar transporters (STPs) in A. flavus remain largely uncharacterized. In this study, we systematically investigated three putative STP genes (G4B84_001982, G4B84_005374, and G4B84_009351) by comprehensive functional characterization of gene deletion mutants. Growth assays revealed that G4B84_001982 and G4B84_005374 mediate uptake of diverse sugar substrates, while G4B84_009351 appeared to be non-essential under tested conditions. Heterologous expressions in the hexose transport-deficient Saccharomyces cerevisiae strain confirmed their sugar transporter activity. Phenotypic analysis revealed that the Δ1982 and Δ5374 mutants showed pleiotropic defects, including impaired growth, reduced sporulation, delayed germination, increased sensitivity to cell wall stressors, and completely abolished sclerotium formation. Pathogenicity assays demonstrated that the two mutants exhibited attenuated virulence in both plants (crop seeds) and animal (Galleria mellonella) infection model. Our findings highlight the essential of two STPs in A. flavus development, stress tolerance, and pathogenicity, offering insights into sugar-mediated pathogenicity in this economically and medically important fungus.
期刊介绍：
Frontiers in Cellular and Infection Microbiology is a leading specialty journal, publishing rigorously peer-reviewed research across all pathogenic microorganisms and their interaction with their hosts. Chief Editor Yousef Abu Kwaik, University of Louisville is supported by an outstanding Editorial Board of international experts. This multidisciplinary open-access journal is at the forefront of disseminating and communicating scientific knowledge and impactful discoveries to researchers, academics, clinicians and the public worldwide.
Frontiers in Cellular and Infection Microbiology includes research on bacteria, fungi, parasites, viruses, endosymbionts, prions and all microbial pathogens as well as the microbiota and its effect on health and disease in various hosts. The research approaches include molecular microbiology, cellular microbiology, gene regulation, proteomics, signal transduction, pathogenic evolution, genomics, structural biology, and virulence factors as well as model hosts. Areas of research to counteract infectious agents by the host include the host innate and adaptive immune responses as well as metabolic restrictions to various pathogenic microorganisms, vaccine design and development against various pathogenic microorganisms, and the mechanisms of antibiotic resistance and its countermeasures.
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