title: The antagonistic strain Bacillus subtilis UMAF6639 also confers protection to melon plants against cucurbit powdery mildew by activation of jasmonate- and salicylic acid-dependent defence responses.
abstract: Biological control of plant diseases has gained acceptance in recent years. Bacillus subtilis UMAF6639 is an antagonistic strain specifically selected for the efficient control of the cucurbit powdery mildew fungus Podosphaera fusca, which is a major threat to cucurbits worldwide. The antagonistic activity relies on the production of the antifungal compounds iturin and fengycin. In a previous study, we found that UMAF6639 was able to induce systemic resistance (ISR) in melon and provide additional protection against powdery mildew. In the present work, we further investigated in detail this second mechanism of biocontrol by UMAF6639. First, we examined the signalling pathways elicited by UMAF6639 in melon plants, as well as the defence mechanisms activated in response to P. fusca. Second, we analysed the role of the lipopeptides produced by UMAF6639 as potential determinants for ISR activation. Our results demonstrated that UMAF6639 confers protection against cucurbit powdery mildew by activation of jasmonate- and salicylic acid-dependent defence responses, which include the production of reactive oxygen species and cell wall reinforcement. We also showed that surfactin lipopeptide is a major determinant for stimulation of the immune response. These results reinforce the biotechnological potential of UMAF6639 as a biological control agent.
authors.affiliation: Instituto de Hortofruticultura Subtropical y Mediterránea 'La Mayora'-IHSM-UMA-CSIC, Departamento de Microbiología, Universidad de Málaga, Bulevar Louis Pasteur 31-Campus Universitario de Teatinos, 29071 Málaga, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: García-Gutiérrez
authors.forename: Houda
authors.initials: H
authors.lastname: Zeriouh
authors.forename: Diego
authors.initials: D
authors.lastname: Romero
authors.forename: Jaime
authors.initials: J
authors.lastname: Cubero
authors.forename: Antonio
authors.initials: A
authors.lastname: de Vicente
authors.forename: Alejandro
authors.initials: A
authors.lastname: Pérez-García
mesh_terms: D000898:Antibiosis; D000935:Antifungal Agents / Q000378:metabolism; D001203:Ascomycota / Q000502:physiology*; D001412:Bacillus subtilis / Q000145:classification / Q000378:metabolism / Q000502:physiology*; D061046:Biological Control Agents; D019662:Cucurbitaceae / Q000276:immunology* / Q000382:microbiology; D003517:Cyclopentanes / Q000378:metabolism*; D055666:Lipopeptides / Q000276:immunology / Q000378:metabolism; D054883:Oxylipins / Q000378:metabolism*; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D018515:Plant Leaves / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism*
chemical_list: D000935:Antifungal Agents; D061046:Biological Control Agents; D003517:Cyclopentanes; D055666:Lipopeptides; D054883:Oxylipins; D017382:Reactive Oxygen Species; C011006:jasmonic acid; D020156:Salicylic Acid