文献类型：期刊文献

英文题名：Regulatory effect of fadR on the inhibition of Aspergillus flavus infection of walnut kernels by Enterobacter ludwigii AA4

作者：Yuan, Zhibo[1,2] Zan, Yibo[1,2] Li, Xu[3] Lu, Bin[4] Chao, Yanjie[5] Xiong, Xinwu[4] Yao, Yanpo[6] Wu, Di[1,2] Niu, Ben[1,2] Pei, Dong[7]

第一作者：Yuan, Zhibo

通信作者：Niu, B[1]

机构：[1]Northeast Forestry Univ, State Key Lab Tree Genet & Breeding, Harbin 150040, Peoples R China;[2]Northeast Forestry Univ, Coll Life Sci, Harbin 150040, Peoples R China;[3]Chinese Acad Agr Sci, Inst Food Sci & Technol, Key Lab Agroprod Qual & Safety Control Storage & T, Minist Agr & Rural Affairs, Beijing 100193, Peoples R China;[4]Yunnan Acad Forestry & Grassland, Lab Forest Plant Cultivat & Utilizat, Key Lab Rare & Endangered Forest Plants, State Forestry Adm, Kunming 650201, Peoples R China;[5]Shanghai Inst Immun & Infect, Ctr Microbes Dev & Hlth, Microbial RNA Syst Biol Unit, Shanghai 200031, Peoples R China;[6]Minist Agr & Rural Affairs, Agroenvironm Protect Inst, Tianjin 300191, Peoples R China;[7]Chinese Acad Forestry, State Key Lab Tree Genet & Breeding, Key Lab Tree Breeding & Cultivat, Res Inst Forestry,State Forestry & Grassland Adm, Beijing 100091, Peoples R China

年份：2026

卷号：304

外文期刊名：MICROBIOLOGICAL RESEARCH

收录：;EI(收录号：20254919650489);Scopus(收录号：2-s2.0-105023644061);WOS:【SCI-EXPANDED(收录号:WOS:001632666000001)】；

基金：This study was supported by the National Key R&D Program of China (grant number 2023YFD2200303), the Xinjiang "Jie Bang Gua Shuai" Research Project (grant number 2023-10), the "Tianchi Talents" Introduction Plan, and the Innovation Project of State Key Laboratory of Tree Genetics and Breeding (Northeast Forestry University) (grant number 2019A01).

语种：英文

外文关键词：Aspergillus flavus; Aflatoxin; Enterobacter ludwigii; Biofilm formation; fadR; Rcs phosphorelay system

摘要：Mycotoxin contamination of nuts, frequently attributed to inappropriate storage, causes substantial economic losses and health concerns globally. Biological control using beneficial microorganisms has emerged as an environment friendly method for efficient mitigation of Aspergillus flavus pollution and consequent mycotoxin elimination in foodstuffs. Nevertheless, the exact mechanisms by which these biocontrol microbes protect nuts from this toxigenic fungus remain largely unknown. Using a fungal infection assay, we observed a remarkable inhibitory effect of Enterobacter ludwigii AA4 against the growth of A. flavus colonizing walnut kernels and aflatoxin B1 production. Mutant E. ludwigii AA4 strains, generated by genetically modifying five biofilm-related genes, notably fadR (which encodes a transcriptional regulator), exhibited significantly impaired biofilm development and reduced efficacy in suppressing A. flavus. These results indicated that biofilm establishment is indispensable for the inhibitory effect of E. ludwigii AA4 against A. flavus. We further investigated the kernel colonization of fadR knockout mutant, which exhibited the most pronounced reduction in biofilm formation, via colony counting and laser scanning confocal microscopy. We found that fadR contributed to the suppression of A. flavus by influencing bacterial biofilm production and kernel settlement. Gene expression analysis and sitedirected mutagenesis revealed that fadR modulated biofilm development by negatively regulating the transcription of rcsA, an auxiliary protein gene within the Rcs phosphorelay system, potentially by influencing acetyl phosphate-mediated RcsB phosphorylation. These findings highlight the potential of AA4 in the biological control of A. flavus contamination in walnut kernels.