title: LetR is a TetR family transcription factor from Lysobacter controlling antifungal antibiotic biosynthesis.
abstract: Heat-stable antifungal factor (HSAF) is a newly identified and broad-spectrum antifungal antibiotic from Lysobacter enzymogenes, a ubiquitous environmental proteobacterium. Yet, the regulatory mechanism for HSAF biosynthesis in L. enzymogenes remains poorly understood. Here, we report the identification of a TetR-family protein Le1552 (LetR) from L. enzymogenes strain OH11 that is involved in transcriptional repression of HSAF production. Bacterial one-hybrid and gel mobility shift assays show that LetR directly binds to PHSAF (the promoter region of the HSAF biosynthesis operon). A DNA truncation assay further reveals a core region in PHSAF that is responsible for LetR binding. In-frame deletion of letR in wild-type OH11 is found to significantly increase HSAF levels and key biosynthetic gene transcription, while overexpression of letR in the wild-type background remarkably reduces HSAF levels as well as related gene expression instead. Together, we have identified not only a new regulator for the HSAF biosynthesis but also constructed a higher HSAF-producing deletion strain (ΔletR) of L. enzymogenes, which shall be of great value in promoting HSAF production for pharmaceutical and biological control purposes.
authors.affiliation: College of Plant Protection, Nanjing Agricultural University, Nanjing City, Jiangsu Province, 210095, People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.affiliation: College of Plant Protection, Nanjing Agricultural University, Nanjing City, Jiangsu Province, 210095, People's Republic of China.
authors.forename: Hongfu
authors.initials: H
authors.lastname: Chen
authors.affiliation: College of Plant Protection, Nanjing Agricultural University, Nanjing City, Jiangsu Province, 210095, People's Republic of China. glqian@njau.edu.cn.
authors.forename: Guoliang
authors.initials: G
authors.lastname: Qian
authors.affiliation: College of Plant Protection, Nanjing Agricultural University, Nanjing City, Jiangsu Province, 210095, People's Republic of China. fqliu20011@sina.com.|Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, People's Republic of China. fqliu20011@sina.com.
authors.forename: Fengquan
authors.initials: F
authors.lastname: Liu
mesh_terms: D000935:Antifungal Agents / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D053528:Lysobacter / Q000235:genetics* / Q000378:metabolism; D005810:Multigene Family; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D000935:Antifungal Agents; D001426:Bacterial Proteins; D014157:Transcription Factors
keywords: Antibiotics; HSAF; Lysobacter; Regulation; TetR