title: Gamma-polyglutamic acid (gamma-PGA) produced by Bacillus amyloliquefaciens C06 promoting its colonization on fruit surface.
abstract: Bacillus amyloliquefaciens C06, an effective biological agent in controlling brown rot of stone fruit caused by Monilinia fructicola, was also found to produce extra-cellular mucilage and form mucoid colonies on semi-solid surfaces. This study aimed to characterize the extra-cellular mucilage produced by B. amyloliquefaciens C06 using transposon mutagenesis and biochemical and physical analyses. The mucilage production in B. amyloliquefaciens C06 was demonstrated to be associated with ywsC gene expression and characterized to be of high molecular weight, consisted of only glutamic acid and linked with non-peptide bonds, thus identified as gamma-polyglutamic acid (gamma-PGA). Compared with wild type B. amyloliquefaciens C06, its mutants deficient in producing gamma-PGA, e.g. M106 and C06DeltaywsC showed less efficiency in biofilm formation, surface adhesion and swarming ability. It was also demonstrated that gamma-PGA was not essential for C06 to form colony on semi-solid surfaces, but was able to improve its colony structure. In vivo evaluation showed that disruption of gamma-PGA production in C06DeltaywsC impaired its efficiency of colonizing apple surfaces.
authors.affiliation: Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, Nanjing, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Dan
authors.initials: D
authors.lastname: He
authors.forename: Xiu-zhen
authors.initials: XZ
authors.lastname: Li
authors.forename: Shengfeng
authors.initials: S
authors.lastname: Gao
authors.forename: Huijun
authors.initials: H
authors.lastname: Wu
authors.forename: Wenzhe
authors.initials: W
authors.lastname: Liu
authors.forename: Xuewen
authors.initials: X
authors.lastname: Gao
authors.forename: Ting
authors.initials: T
authors.lastname: Zhou
mesh_terms: D001407:Bacillus / Q000235:genetics / Q000502:physiology*; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018441:Biofilms; D005638:Fruit / Q000382:microbiology*; D015964:Gene Expression Regulation, Bacterial; D027845:Malus / Q000382:microbiology; D009154:Mutation; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; C511775:poly(gamma-glutamic acid); D011099:Polyglutamic Acid