title: Putative use of a Bacillus subtilis L194 strain for biocontrol of Phoma medicaginis in Medicago truncatula seedlings.
abstract: An antagonist L194 strain against Phoma medicaginis pathogenic fungi was isolated from Tunisian soil (vicinity of Tunis) and identified as Bacillus subtilis based on biochemical characteristics and partial 16S rDNA sequence. When cells were grown in a minimal medium for 24 h, spore culture supernatant exhibited 2-fold higher antifungal activity than vegetative cells. MALDI-TOF mass spectrometry analysis showed that L194 spores produced mainly iturins, surfactins and fengycins with long-chain fatty acids, and other not yet identified compounds. Both vegetative cells and spores of L194 efficiently reduced germination of P. medicaginis conidia. As revealed by atomic force microscopy, L194 spores modified conidia morphology from a regular to a deflated shape. Data suggest that lipopeptides interacted with the cytoplasmic membrane, causing pore formation. In vivo, L194 spores were highly protective against P. medicaginis by reducing disease symptoms and alleviating growth disturbance of Medicago truncatula seedlings. As a whole, the lipopeptide-producing L194 strain may be successfully used in biocontrol of plant diseases induced by phytopathogenic fungi such as P. medicaginis.
authors.affiliation: Laboratoire des Substances Bioactives, Centre de Biotechnologie de Borj-Cedria, BP-901, 2050 Hammam-lif, Tunisia.
authors.forename: Imen
authors.initials: I
authors.lastname: Ben Slimene
authors.forename: Olfa
authors.initials: O
authors.lastname: Tabbene
authors.forename: Naceur
authors.initials: N
authors.lastname: Djebali
authors.forename: Pascal
authors.initials: P
authors.lastname: Cosette
authors.forename: Jean Marie
authors.initials: JM
authors.lastname: Schmitter
authors.forename: Thierry
authors.initials: T
authors.lastname: Jouenne
authors.forename: Maria-Camino
authors.initials: MC
authors.lastname: Urdaci
authors.forename: Ferid
authors.initials: F
authors.lastname: Limam
mesh_terms: D000898:Antibiosis; D000935:Antifungal Agents / Q000378:metabolism; D001203:Ascomycota / Q000254:growth & development* / Q000648:ultrastructure; D001412:Bacillus subtilis / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism / Q000502:physiology*; D001426:Bacterial Proteins / Q000378:metabolism; D015373:Bacterial Typing Techniques; D002462:Cell Membrane / Q000187:drug effects; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D055666:Lipopeptides / Q000378:metabolism; D046913:Medicago truncatula / Q000382:microbiology*; D018625:Microscopy, Atomic Force; D008969:Molecular Sequence Data; D010572:Pest Control, Biological / Q000379:methods*; D010935:Plant Diseases / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D036226:Seedlings / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D013172:Spores, Fungal / Q000254:growth & development / Q000648:ultrastructure; D014416:Tunisia
chemical_list: D000935:Antifungal Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D055666:Lipopeptides; D012336:RNA, Ribosomal, 16S