title: Diversity analysis of diazotrophic bacteria associated with the roots of tea (Camellia sinensis (L.) O. Kuntze).
abstract: The diversity elucidation by amplified ribosomal DNA restriction analysis and 16S rDNA sequencing of 96 associative diazotrophs, isolated from the feeder roots of tea on enriched nitrogen-free semisolid media, revealed the predominance of Gram-positive over Gram-negative bacteria within the Kangra valley in Himachal Pradesh, India. The Gram-positive bacteria observed belong to two taxonomic groupings; Firmicutes, including the genera Bacillus and Paenibacillus; and Actinobacteria, represented by the genus Microbacterium. The Gram-negative bacteria included alpha-Proteobacteria genera Brevundimonas, Rhizobium, and Mesorhizobium; gamma-Proteobacteria genera Pseudomonas and Stenotrophomonas; and beta-Proteobacteria genera Azospira, Burkholderia, Delftia, Herbaspirillum and Ralstonia. The low level of similarity of two isolates, with the type strains Paenibacillus xinjiangensis and Mesorhizobium albiziae, suggests the possibility of raising species novum. The bacterial strains of different phylogenetic groups exhibited distinct carbon-source utilization patterns and fatty acid methyl ester profiles. The strains differed in their nitrogenase activities with relatively high activity seen in the Gramnegative strains exhibiting the highest similarity to Azospira oryzae, Delftia lacustris and Herbaspirillum huttiense.
authors.affiliation: Plant Pathology and Microbiology Laboratory, Hill Area Tea Science Division, Institute of Himalayan Bioresource Technology, Council of Scientific and Industrial Research, P.O. Box 6, Palampur (H.P), India. gal_arvind@yahoo.co.in
authors.forename: Arvind
authors.initials: A
authors.lastname: Gulati
authors.forename: Swati
authors.initials: S
authors.lastname: Sood
authors.forename: Praveen
authors.initials: P
authors.lastname: Rahi
authors.forename: Rishu
authors.initials: R
authors.lastname: Thakur
authors.forename: Sunita
authors.initials: S
authors.lastname: Chauhan
authors.forename: Isha
authors.initials: I
authors.lastname: Chawla
mesh_terms: D028241:Camellia sinensis / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D014644:Genetic Variation; D006090:Gram-Negative Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D006094:Gram-Positive Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S