| Title: | Impact of spontaneous mutations on physiological traits and biocontrol activity of Pseudomonas chlororaphis M71 |
| Author(s): | Raio A; Brilli F; Baraldi R; Neri L; Puopolo G; |
| Address: | "Institute for Sustainable Plant Protection, National Research Council, Via Madonna del Piano 10, 50019, Sesto Fiorentino, FI, Italy. Electronic address: aida.raio@ipsp.cnr.it. Institute for Sustainable Plant Protection, National Research Council, Via Madonna del Piano 10, 50019, Sesto Fiorentino, FI, Italy. Institute of BioEconomy, National Research Council, Bologna, Italy. Center Agriculture Food Environment (C3A), University of Trento, via E. Mach 1, San Michele all'Adige, 38010, Italy. Department of Sustainable Agro-ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, San Michele all'Adige, 38010, Italy" |
| DOI: | 10.1016/j.micres.2020.126517 |
| ISSN/ISBN: | 1618-0623 (Electronic) 0944-5013 (Linking) |
| Abstract: | "Three morphological mutants (M71a, M71b, M71c) of the antagonist Pseudomonas chlororaphis M71, naturally arose during a biocontrol trial against the phytopathogenic fungus Fusarium oxysporum f.sp. radicis-lycopersisci. In this study, the three mutants were investigated to elucidate their role in the biocontrol of plant pathogens. M71a and M71b phenotypes were generated by a mutation in the two-component system GacS/GacA. The mutation determined an increase in siderophore production and an impaired ability to release proteases, to swarm, to produce phenazine and AHLs and to colonize tomato roots. In vitro antagonistic activity against different plant pathogens was partially reduced in M71a, while M71b resulted effective only against Pythium ultimum. Biocontrol efficacy against Fusarium oxysporum f.sp. radicis-lycopersisci, was partially reduced in M71a and completely lost in M71b. M71c phenotype was impaired in swarming motility, did not produce biofilms and its antagonistic activity was similar to the parental M71 strain. M71c showed an enhanced ability to colonize tomato roots, on which its progeny in part reverted to the M71 parental phenotype. Volatile organic compounds (VOCs) emitted by all four strains, inhibited the growth of Clavibacter michiganensis subsp. michiganensis and Seiridium cardinale in vitro. Real-time screening of VOCs by PTR-MS combined with GC-MS analysis, showed that methanethiol was the main component of the blend produced by all four M71 strains. However, the emissions of hydrogen cyanide, dimethyl disulfide, 1,3-butadiene and acetone were significantly affected by the three different mutations. These findings highlight that the simultaneous presence of different M71 phenotypes may improve, through the integration of different mechanisms, the ecological fitness and biocontrol efficacy of P. chlororaphis M71" |
| Keywords: | "Bacterial Proteins/genetics Biological Control Agents/*metabolism/pharmacology Fusarium/drug effects Solanum lycopersicum/microbiology *Mutation Pest Control, Biological Phenazines/metabolism/pharmacology Phenotype Plant Diseases/microbiology Plant Roots/;" |
| Notes: | "MedlineRaio, Aida Brilli, Federico Baraldi, Rita Neri, Luisa Puopolo, Gerardo eng Germany 2020/06/15 Microbiol Res. 2020 Oct; 239:126517. doi: 10.1016/j.micres.2020.126517. Epub 2020 Jun 3" |
