title: Lipopeptides from a novel Bacillus methylotrophicus 39b strain suppress Agrobacterium crown gall tumours on tomato plants.
abstract: BACKGROUND
  This study aims to characterise the antibacterial activity of a novel Bacillus methylotrophicus strain named 39b against tumourigenic Agrobacterium tumefaciens C58 and B6 strains. It also aims to identify the compound that is responsible for its activity and to evaluate its efficiency to control crown gall disease in tomato plants.
  
  
  RESULTS
  B. methylotrophicus strain 39b was found to stop the growth of phytopathogenic A. tumefaciens strains in in vitro experiments. Lipopeptides - surfactins, iturins and fengycins - were detected under various isoforms by mass spectrometry analysis of the methanolic extract. The active principle acting against Agrobacterium strains was isolated from TLC plates and identified by mass spectrometry as surfactin. The strain was effective in reducing the weight and the number of galls induced by A. tumefaciens strains on tomato plants. Total inhibition of gall formation was observed using the antibacterial compounds.
  
  
  CONCLUSIONS
  B. methylotrophicus strain 39b exhibited antibacterial activity against phytopathogenic A. tumefaciens C58 and B6 both in vitro and in vivo. Lipopeptides are the main compounds that confer the biocontrol ability. This strain has the potential to be developed as a biological control agent for crown gall disease. © 2016 Society of Chemical Industry.
authors.affiliation: Biopesticides Laboratory, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
authors.forename: Olfa
authors.initials: O
authors.lastname: Frikha-Gargouri
authors.affiliation: Biopesticides Laboratory, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
authors.forename: Dorra
authors.initials: D
authors.lastname: Ben Abdallah
authors.affiliation: Biopesticides Laboratory, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
authors.forename: Imen
authors.initials: I
authors.lastname: Ghorbel
authors.affiliation: Biopesticides Laboratory, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
authors.forename: Ikram
authors.initials: I
authors.lastname: Charfeddine
authors.affiliation: Analysis Laboratory, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
authors.forename: Lobna
authors.initials: L
authors.lastname: Jlaiel
authors.affiliation: Olive Institute, University of Sfax, Sfax, Tunisia.
authors.forename: Mohamed Ali
authors.initials: MA
authors.lastname: Triki
authors.affiliation: Biopesticides Laboratory, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia.
authors.forename: Slim
authors.initials: S
authors.lastname: Tounsi
mesh_terms: D016960:Agrobacterium tumefaciens / Q000187:drug effects*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001407:Bacillus / Q000737:chemistry* / Q000145:classification; D055666:Lipopeptides / Q000032:analysis / Q000494:pharmacology*; D018551:Solanum lycopersicum / Q000382:microbiology*; D013058:Mass Spectrometry; D010935:Plant Diseases / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D055666:Lipopeptides
keywords: Bacillus methylotrophicus; bacterial plant disease; biological control agent; mass spectrometry