title: Pectin Enhances Bio-Control Efficacy by Inducing Colonization and Secretion of Secondary Metabolites by Bacillus amyloliquefaciens SQY 162 in the Rhizosphere of Tobacco.
abstract: Bacillus amyloliquefaciens is a plant-beneficial Gram-positive bacterium involved in suppressing soil-borne pathogens through the secretion of secondary metabolites and high rhizosphere competence. Biofilm formation is regarded as a prerequisite for high rhizosphere competence. In this work, we show that plant extracts affect the chemotaxis and biofilm formation of B. amyloliquefaciens SQY 162 (SQY 162). All carbohydrates tested induced the chemotaxis and biofilm formation of the SQY 162 strain; however, the bacterial growth rate was not influenced by the addition of carbohydrates. A strong chemotactic response and biofilm formation of SQY 162 were both induced by pectin through stimulation of surfactin synthesis and transcriptional expression of biofilm formation related matrix genes. These results suggested that pectin might serve as an environmental factor in the stimulation of the biofilm formation of SQY 162. Furthermore, in pot experiments the surfactin production and the population of SQY 162 in the rhizosphere significantly increased with the addition of sucrose or pectin, whereas the abundance of the bacterial pathogen Ralstonia decreased. With increased production of secondary metabolites in the rhizosphere of tobacco by SQY 162 and improved colonization density of SQY 162 in the pectin treatment, the disease incidences of bacterial wilt were efficiently suppressed. The present study revealed that certain plant extracts might serve as energy sources or environmental cues for SQY 162 to enhance the population density on tobacco root and bio-control efficacy of tobacco bacterial wilt.
authors.affiliation: National Engineering Research Center for Organic-based Fertilizers, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China; Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Key Laboratory of Ministry of Education, College of Energy and Environmental Sciences, Yunnan Normal University, Kunming, 650500, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Wu
authors.affiliation: National Engineering Research Center for Organic-based Fertilizers, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Zhiying
authors.initials: Z
authors.lastname: Fang
authors.affiliation: National Engineering Research Center for Organic-based Fertilizers, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Guo
authors.affiliation: National Engineering Research Center for Organic-based Fertilizers, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Pan
authors.affiliation: National Engineering Research Center for Organic-based Fertilizers, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Shi
authors.affiliation: National Engineering Research Center for Organic-based Fertilizers, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Saifei
authors.initials: S
authors.lastname: Yuan
authors.affiliation: Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Key Laboratory of Ministry of Education, College of Energy and Environmental Sciences, Yunnan Normal University, Kunming, 650500, China.
authors.forename: Huilin
authors.initials: H
authors.lastname: Guan
authors.affiliation: School of Life Sciences, Yunnan Normal University, Kunming, 650500, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Gong
authors.affiliation: National Engineering Research Center for Organic-based Fertilizers, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Biao
authors.initials: B
authors.lastname: Shen
authors.affiliation: National Engineering Research Center for Organic-based Fertilizers, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
authors.forename: Qirong
authors.initials: Q
authors.lastname: Shen
mesh_terms: D001407:Bacillus / Q000187:drug effects* / Q000502:physiology*; D018441:Biofilms / Q000187:drug effects; D002241:Carbohydrates / Q000737:chemistry / Q000494:pharmacology; D002633:Chemotaxis / Q000276:immunology; D055666:Lipopeptides / Q000096:biosynthesis; D010368:Pectins / Q000494:pharmacology*; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology; D058441:Rhizosphere; D064210:Secondary Metabolism / Q000187:drug effects*; D014026:Nicotiana / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology*
chemical_list: D002241:Carbohydrates; D055666:Lipopeptides; D010368:Pectins