title: Diversity and functional traits of culturable microbiome members, including cyanobacteria in the rice phyllosphere.
abstract: The diversity and abundance of culturable microbiome members of the rice phyllosphere was investigated using cv. Pusa Punjab Basmati 1509. Both diversity and species richness of bacteria were significantly higher in plants in pots in a semi-controlled environment than those in fields. Application of fertilisers reduced both diversity and species richness in field-grown plants under a conventional flooded system of rice intensification (SRI) and in dry-seeded rice (DSR) modes. Sequence analyses of 16S rDNA of culturable bacteria, those selected after amplified ribosomal DNA restriction analysis (ARDRA), showed the dominance of α-proteobacteria (35%) and actinobacteria (38%); Pantoea, Exiguobacterium and Bacillus were common among the culturable phyllospheric bacteria. About 34% of 83 culturable bacterial isolates had higher potential (>2 μg·ml(-1) ) for indole acetic acid production in the absence of tryptophan. Interestingly, the phyllosphere bacterial isolates from the pot experiment had significantly higher potential for nitrogen fixation than isolates from the field experiment. Enrichment for cyanobacteria showed both unicellular forms and non-heterocystous filaments under aerobic as well as anaerobic conditions. PCR-DGGE analysis of these showed that aerobic and anaerobic conditions as well as the three modes of cultivation of rice in the field strongly influenced the number and abundance of phylotypes. The adaptability and functional traits of these culturable microbiome members suggest enormous diversity in the phyllosphere, including potential for plant growth promotion, which was also significantly influenced by the different methods of growing rice.
authors: Division of Microbiology, ICAR - Indian Agricultural Research Institute (IARI), New Delhi, India.
authors: S
authors: S
authors: Venkatachalam
authors: Division of Microbiology, ICAR - Indian Agricultural Research Institute (IARI), New Delhi, India.
authors: K
authors: K
authors: Ranjan
authors: Division of Microbiology, ICAR - Indian Agricultural Research Institute (IARI), New Delhi, India.
authors: R
authors: R
authors: Prasanna
authors: Division of Microbiology, ICAR - Indian Agricultural Research Institute (IARI), New Delhi, India.
authors: B
authors: B
authors: Ramakrishnan
authors: Division of Microbiology, ICAR - Indian Agricultural Research Institute (IARI), New Delhi, India.
authors: S
authors: S
authors: Thapa
authors: Division of Microbiology, ICAR - Indian Agricultural Research Institute (IARI), New Delhi, India.
authors: A
authors: A
authors: Kanchan
mesh_terms: D001419:Bacteria / Q000235:genetics* / Q000302:isolation & purification; D000458:Cyanobacteria / Q000235:genetics* / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D007210:Indoleacetic Acids / Q000378:metabolism; D064307:Microbiota; D009584:Nitrogen / Q000378:metabolism; D009586:Nitrogen Fixation; D012275:Oryza / Q000382:microbiology*; D010802:Phylogeny; D035261:Plant Components, Aerial / Q000382:microbiology*; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D007210:Indoleacetic Acids; C030737:indoleacetic acid; D009584:Nitrogen
keywords: Cyanobacteria; indole acetic acid; leaves; microbiome; nitrogen fixation; phylotypes