title: Diversity and N-acyl-homoserine lactone production by Gammaproteobacteria associated with Avicennia marina rhizosphere of South Indian mangroves.
abstract: The diversity of N-acyl-homoserine lactone (AHL)-producing rhizosphere bacterial community associated with Avicennia marina in the mangrove ecosystems of South India was investigated. Approximately 800 rhizobacteria were isolated from A. marina, and they were screened for the production of AHL using two biosensors, Chromobacterium violaceum CV026 and Agrobacterium tumefaciens NTL4 (pZLR4). Among the total isolates screened, 7% of the rhizobacteria showed positive induction for AHL signals. The BOX-PCR profile of 56 positive isolates represented 11 distinct genotypic groups. Phylogenetic analyses of the 16S rRNA sequences of 16 representatives showed that the isolates belonged to the class Gammaproteobacteria, which represented six different genera: Pseudomonas, Aeromonas, Vibrio, Photobacterium, Serratia and Halomonas. The study also identified three AHL-producing species, namely, Photobacterium halotolerans MSSRF QS48, Vibrio xiamenensis MSSRF QS47 and Pseudomonas sp. MSSRF QS1 that had not been reported previously. AHL profiling by TLC detected short chains C4, C6 and C8-HSL, and long chains C10 and C12-HSL with both unsubstituted and substituted side chains among the 16 representative AHL positives. This is the first report concerning the diversity of AHL-producing Gammaproteobacteria from mangrove ecosystems exhibiting diverse AHL profiles.
authors.affiliation: Microbiology Department, M.S. Swaminathan Research Foundation, 3rd Cross Taramani Institutional Area, Chennai 600113, India.
authors.forename: Ganga
authors.initials: G
authors.lastname: Viswanath
authors.affiliation: Microbiology Department, M.S. Swaminathan Research Foundation, 3rd Cross Taramani Institutional Area, Chennai 600113, India.
authors.forename: Sekar
authors.initials: S
authors.lastname: Jegan
authors.affiliation: Microbiology Department, M.S. Swaminathan Research Foundation, 3rd Cross Taramani Institutional Area, Chennai 600113, India.
authors.forename: Viswanathan
authors.initials: V
authors.lastname: Baskaran
authors.affiliation: Microbiology Department, M.S. Swaminathan Research Foundation, 3rd Cross Taramani Institutional Area, Chennai 600113, India.
authors.forename: Raju
authors.initials: R
authors.lastname: Kathiravan
authors.affiliation: Microbiology Department, M.S. Swaminathan Research Foundation, 3rd Cross Taramani Institutional Area, Chennai 600113, India. Electronic address: prabavathyvr@mssrf.res.in.
authors.forename: Vaiyapuri Ramalingam
authors.initials: VR
authors.lastname: Prabavathy
mesh_terms: D054742:Acyl-Butyrolactones / Q000378:metabolism*; D032407:Avicennia / Q000382:microbiology*; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D020563:Gammaproteobacteria / Q000378:metabolism*; D007194:India; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D058441:Rhizosphere; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D053833:Wetlands
chemical_list: D054742:Acyl-Butyrolactones; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S
keywords: 16S rRNA analysis; BOX-PCR; Mangrove; N-acyl-homoserine lactone (AHL); Rhizobacteria; TLC