title: Control of Wilt and Rot Pathogens of Tomato by Antagonistic Pink Pigmented Facultative MethylotrophicDelftia lacustrisandBacillusspp.
abstract: The studies on the biocontrol potential of pink pigmented facultative methylotrophic (PPFM) bacteria other than the genusMethylobacteriumare scarce. In the present study, we report three facultative methylotrophic isolates; PPO-1, PPT-1, and PPB-1, respectively, identified asDelftia lacustris, Bacillus subtilis, andBacillus cereusby 16S rRNA gene sequence analysis. Hemolytic activity was tested to investigate the potential pathogenicity of isolates to plants and humans, the results indicates that the isolates PPO-1, PPT-1, and PPB-1 are not pathogenic strains. Underin vitroconditions,D. lacustrisPPO-1,B.subtilisPPT-1, andB.cereusPPB-1 showed direct antagonistic effect by inhibiting the mycelial growth of fungal pathogens;Fusarium oxysporumf. sp.lycopersici(2.15, 2.05, and 1.95 cm),Sclerotium rolfsii(2.14, 2.04, and 1.94 cm),Pythium ultimum(2.12, 2.02, and 1.92 cm), andRhizoctonia solani(2.18, 2.08, and 1.98 cm) and also produced volatile inhibitory compounds. Under plant growth chamber condition methylotrophic bacterial isolates;D.lacustrisPPO-1,B.subtilisPPT-1, andB. cereusPPB-1 significantly reduced the disease incidence of tomato. Under greenhouse condition,D.lacustrisPPO-1,B.subtilisPPT-1, andB.cereusPPB-1 inoculated tomato plants, when challenged withF.oxysporumf. sp.lycopersici, S.rolfsii, P.ultimum, andR.solani, increased the pathogenesis related proteins (β-1,3-glucanase and chitinase) and defense enzymes (phenylalanine ammonia lyase, peroxidase, polyphenol oxidase, and catalase) on day 5 after inoculation. In the current study, we first report the facultative methylotrophy in pink pigmentedD. lacustris, B.subtilis, andB.cereusand their antagonistic potential against fungal pathogens. Direct antagonistic and ISR effects of these isolates against fungal pathogens of tomato evidenced their possible use as a biocontrol agent.
authors.affiliation: Department of Agricultural Microbiology, Agricultural College and Research Institute, Tamil Nadu Agricultural University Madurai, India.
authors.forename: Veeranan
authors.initials: V
authors.lastname: Janahiraman
authors.affiliation: Department of Agricultural Microbiology, Agricultural College and Research Institute, Tamil Nadu Agricultural University Madurai, India.
authors.forename: Rangasamy
authors.initials: R
authors.lastname: Anandham
authors.affiliation: Korean Agricultural Culture Collection, National Academy of Agricultural Science, Rural Development Administration Jeonju, South Korea.
authors.forename: Soon W
authors.initials: SW
authors.lastname: Kwon
authors.affiliation: Department of Agricultural Microbiology, Agricultural College and Research Institute, Tamil Nadu Agricultural UniversityMadurai, India; Department of Environmental and Biological Chemistry, Chungbuk National UniversityCheongju, South Korea.
authors.forename: Subbiah
authors.initials: S
authors.lastname: Sundaram
authors.affiliation: Department of Plant Pathology, Agricultural College and Research Institute, Tamil Nadu Agricultural University Coimbatore, India.
authors.forename: Veeranan
authors.initials: V
authors.lastname: Karthik Pandi
authors.affiliation: Department of Agricultural Microbiology, Agricultural College and Research Institute, Tamil Nadu Agricultural University Madurai, India.
authors.forename: Ramasamy
authors.initials: R
authors.lastname: Krishnamoorthy
authors.affiliation: Department of Environmental and Biological Chemistry, Chungbuk National University Cheongju, South Korea.
authors.forename: Kiyoon
authors.initials: K
authors.lastname: Kim
authors.affiliation: Department of Environmental and Biological Chemistry, Chungbuk National University Cheongju, South Korea.
authors.forename: Sandipan
authors.initials: S
authors.lastname: Samaddar
authors.affiliation: Department of Environmental and Biological Chemistry, Chungbuk National University Cheongju, South Korea.
authors.forename: Tongmin
authors.initials: T
authors.lastname: Sa
keywords: antagonism; biological control; induced systemic resistance; methylotrophs; pathogenesis-related proteins; tomato