广东农业科学2025，Vol.52Issue(5)：54-63,10.DOI:10.16768/j.issn.1004-874X.2025.05.005
B8N6S4调控黄曲霉生长及黄曲霉毒素B1合成的功能研究
Function of B8N6S4 in Regulating the Growth and Aflatoxin B1 Biosynthesis of Aspergillus flavus
摘要
Abstract
[Objective]The objective of this study is to examine the function of Zn(II)2Cys6 transcription factor B8N6S4 in Aspergillus flavus,and to analyze the role of B8N6S4 in the growth,development,and Aflatoxin B1(AFB1)biosynthesis of A.flavus.[Method]Polyethylene glycol-mediated homologous recombination was used to construct deletion mutants of B8N6S4 gene,and the differences between the deletion mutants and the wild-type strain in terms of growth,development,AFB1 biosynthesis and infection ability of A.flavus were compared.[Result]Bioinformatics analysis showed that B8N6S4 contained a typical GAL4-like Zn(II)2Cys6 DNA-binding domain and a fungal-specific transcription factor domain.Phylogenetic analysis demonstrated that B8N6S4 exhibits the highest sequence similarity(97.99%)with the homologous protein KAB8271990.1 from the high aflatoxin-producing strain A.minisclerotigenes.Using homologous recombination,two A.flavus knockout strains,ΔB8N6S4-1 and ΔB8N6S4-2,were successfully constructed,and the successful deletion of the B8N6S4 gene and correct integration of selection marker genes were verified.Compared with the wild type,there was no significant change in the hyphal growth rate of two ΔB8N6S4 mutant on PDA medium,but the conidia yield was significantly reduced to7.5×106,8.0×106 cells/mL,which was about 5.6 times lower than that of WT(4.4×107 cells/mL).Notably,the sclerotia-forming capacity of the mutants was significantly improved,with the number of sclerotia reaching 767 and 836,which was about twice that of the WT strain(409±39).The results of thin layer chromatography showed that the toxin synthesis ability of ΔB8N6S4-1 and ΔB8N6S4-2 mutants was enhanced,which increased by about 78%and 104%,respectively.In addition,the grain infection test of maize showed that the infection ability of two ΔB8N6S4 mutant was not significantly different from that of wild type.Spore counts following infection revealed comparable sporulation capacity between mutant and wild-type strains.However,AFB1 production of ΔB8N6S4-1 and ΔB8N6S4-2 mutants on maize substrate was significantly increased,which was about 5.2 times and 3.9 times that of WT,respectively.[Conclusion]B8N6S4 is a Zn(II)2Cys6 transcription factor of A.flavus,which positively regulates the asexual sporulation of A.flavus,negatively regulates the formation of sclerotia,and inhibits the biosynthesis of AFB1.ΔB8N6S4 does not directly affect the pathogenicity of A.flavus but significantly enhances its AFB1 production capacity.This study revealed for the first time the regulatory role of B8N6S4 in the aflatoxin biosynthesis network,providing a novel target for the prevention and control strategy to block aflatoxin biosynthesis.关键词
黄曲霉/Zn(II)₂Cys₆转录因子/黄曲霉毒素/B8N6S4/致病性Key words
Aspergillus flavus/Zn(II)2Cys6 transcription factor/aflatoxin/B8N6S4/pathogenicity分类
农业科技引用本文复制引用
张昕泽,蒲睿思,牛锦璐,黄文洁,晏石娟,张文洋,吴绍文..B8N6S4调控黄曲霉生长及黄曲霉毒素B1合成的功能研究[J].广东农业科学,2025,52(5):54-63,10.基金项目
国家自然科学基金(22307022) （22307022）
广东省自然科学基金(2022A1515110962,2024A1515010062) （2022A1515110962,2024A1515010062）
广东省农业科学院科技创新战略专项(高水平农科院建设)(R2023PY-JX024,R2021YJ-YB1004,R2023PY-JG025,2023QZ-NK04,GDNKY-ZQQZ-K5) （高水平农科院建设）
