A novel yellow colony-forming bacterium, strain P3B162^T was isolated from the pokkali rice rhizosphere from Kerala, India, as part of a project study aimed at isolating plant growth beneficial rhizobacteria from saline tolerant pokkali rice and functionally evaluate their abilities to promote plant growth under saline conditions. The novel strain P3B162^T possesses plant growth beneficial traits such as positive growth on 1-aminocyclopropane-1-carboxylic acid (ACC), production of indole acetic acid (IAA) and siderophore. In addition, it also showed important phenotypic characters such as ability to form biofilm and utilization of various components of plant root exudates (sugars, amino acids and organic acids), clearly indicating its lifestyle as a plant rhizosphere associated bacterium. Taxonomically, the novel strain P3B162^T was affiliated to the genus Arthrobacter based on the collective results of phenotypic, genotypic and chemotaxonomic analyses. Moreover, molecular analysis using 16S rRNA gene showed Arthrobacter globiformis NBRC 12137^T, Arthrobacter pascens DSM 20545^T and Arthrobacter liuii DSXY973^T as the closely related phylogenetic neighbours, showing more than 98% 16S rRNA similarity values, whereas the recA gene analysis displayed Arthrobacter liuii JCM 19864^T as the nearest neighbour with 94.7% sequence similarity and only 91.7% to Arthrobacter globiformis LMG 3813^T and 88.7% to Arthrobacter pascens LMG 16255^T. However, the DNA-DNA hybridization values between strain P3B162^T, Arthrobacter globiformis LMG 3813^T, Arthrobacter pascens LMG 16255^T and Arthrobacter liuii JCM 19864^T was below 50%. In addition, the novel strain P3B162^T can be distinguished from its closely related type strains by several phenotypic characters such as colony pigment, tolerance to NaCl, motility, reduction of nitrate, hydrolysis of DNA, acid from sucrose, cell wall sugars and cell wall peptidoglycan structure. In conclusion, the combined results of this study support the classification of strain P3B162^T as a novel Arthrobacter species and we propose Arthrobacter pokkalii sp.nov.as its name. The type strain is P3B162^T (= KCTC 29498^T = MTCC 12358^T).

A facultatively anaerobic, nitrogen-fixing bacterium, strain MSSRF40^T, was isolated from roots of mangrove-associated wild rice (Porteresia coarctata Tateoka). On the basis of 16S rRNA gene sequence similarities, strain MSSRF40^T was shown to belong to the family Enterobacteriaceae, most closely related to Cronobacter muytjensii E603^T (97.2 % sequence similarity), Enterobacter cloacae subsp. dissolvens LMG 2683^T (97.1 %), E. radicincitans D5/23^T (97.1 %) and E. ludwigii EN-119^T (97.0 %). Sequence analysis of rpoB, gyrB and hsp60 genes showed that strain MSSRF40^T had relatively low sequence similarity (<91, <84 and <90 %) to recognized species of different genera of the family Enterobacteriaceae and formed an independent phyletic lineage in all phylogenetic analyses using the 16S rRNA, rpoB, gyrB and hsp60 genes, clearly indicating that strain MSSRF40^T could not be affiliated to any of the recognized genera within the family Enterobacteriaceae. The dominant cellular fatty acids were C_16 : 0, C_16 : 1 ω7c and/or iso-C_15 : 0 2-OH and C_18 : 1 ω7c, similar to those of other members of the Enterobacteriaceae. The DNA G+C content was 50.1 mol%. Phylogenetic distinctiveness and phenotypic differences from its phylogenetic neighbours indicated that strain MSSRF40^T represents a novel species and genus within the family Enterobacteriaceae, for which the name Mangrovibacter plantisponsor gen. nov., sp. nov. is proposed. The type strain of Mangrovibacter plantisponsor is strain MSSRF40^T (=LMG 24236^T =DSM 19579^T).

Genetic diversity of red-pigmented vibrios from different mangrove rhizospheres (Porteresia coarctata, Avicennia marina and Rhizophora mucronata) col