title: Genetic analysis of plant endophytic Pseudomonas putida BP25 and chemo-profiling of its antimicrobial volatile organic compounds.
abstract: Black pepper associated bacterium BP25 was isolated from root endosphere of apparently healthy cultivar Panniyur-5 that protected black pepper against Phytophthora capsici and Radopholus similis - the major production constraints. The bacterium was characterized and mechanisms of its antagonistic action against major pathogens are elucidated. The polyphasic phenotypic analysis revealed its identity as Pseudomonas putida. Multi locus sequence typing revealed that the bacterium shared gene sequences with several other isolates representing diverse habitats. Tissue localization assays exploiting green fluorescence protein expression clearly indicated that PpBP25 endophytically colonized not only its host plant - black pepper, but also other distantly related plants such as ginger and arabidopsis. PpBP25 colonies could be enumerated from internal tissues of plants four weeks post inoculation indicated its stable establishment and persistence in the plant system. The bacterium inhibited broad range of pathogens such as Phytophthora capsici, Pythium myriotylum, Giberella moniliformis, Rhizoctonia solani, Athelia rolfsii, Colletotrichum gloeosporioides and plant parasitic nematode, Radopholus similis by its volatile substances. GC/MS based chemical profiling revealed presence of Heneicosane; Tetratetracontane; Pyrrolo [1,2-a] pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl); Tetracosyl heptafluorobutyrate; 1-3-Eicosene, (E)-; 1-Heneicosanol; Octadecyl trifluoroacetate and 1-Pentadecene in PpBP25 metabolite. Dynamic head space GC/MS analysis of airborne volatiles indicated the presence of aromatic compounds such as 1-Undecene;Disulfide dimethyl; Pyrazine, methyl-Pyrazine, 2,5-dimethyl-; Isoamyl alcohol; Pyrazine, methyl-; Dimethyl trisulfide, etc. The work paved way for profiling of broad spectrum antimicrobial VOCs in endophytic PpBP25 for crop protection.
authors: Division of Plant Pathology, ICAR - Indian Agricultural Research Institute, New Delhi, India.
authors: Neelam
authors: N
authors: Sheoran
authors: Division of Crop Protection, ICAR - Indian Institute of Spices Research, Kozhikode, India.
authors: Agisha
authors: A
authors: Valiya Nadakkakath
authors: Division of Plant Pathology, ICAR - Indian Agricultural Research Institute, New Delhi, India.
authors: Vibhuti
authors: V
authors: Munjal
authors: Division of Agricultural Chemicals, ICAR - Indian Agricultural Research Institute, New Delhi, India.
authors: Aditi
authors: A
authors: Kundu
authors: Division of Crop Protection, ICAR - Central Plantation Crops Research Institute, Kasaragod, India.
authors: Kesavan
authors: K
authors: Subaharan
authors: Division of Crop Protection, ICAR - Central Plantation Crops Research Institute, Kasaragod, India.
authors: Vibina
authors: V
authors: Venugopal
authors: Division of Crop Protection, ICAR - Indian Institute of Spices Research, Kozhikode, India.
authors: Suseelabhai
authors: S
authors: Rajamma
authors: Division of Crop Protection, ICAR - Indian Institute of Spices Research, Kozhikode, India.
authors: Santhosh J
authors: SJ
authors: Eapen
authors: Division of Plant Pathology, ICAR - Indian Agricultural Research Institute, New Delhi, India. Electronic address: kumar@iari.res.in.
authors: Aundy
authors: A
authors: Kumar
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D060026:Endophytes / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D005658:Fungi / Q000187:drug effects / Q000254:growth & development; D008969:Molecular Sequence Data; D010802:Phylogeny; D010838:Phytophthora / Q000187:drug effects / Q000254:growth & development; D029222:Piper nigrum / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology*; D018517:Plant Roots / Q000382:microbiology; D016958:Pseudomonas putida / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D055549:Volatile Organic Compounds / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000890:Anti-Infective Agents; D055549:Volatile Organic Compounds
keywords: Black pepper; Endophytic bacteria; Ginger; Pseudomonas putida; Volatile organic compounds