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Land plants have developed a cuticle preventing uncontrolled water loss. Here we report that an ATP-binding cassette (ABC) subfamily G (ABCG) full transporter is required for leaf water conservation in both wild barley and rice. A spontaneous mutation, eibi1.b, in wild barley has a low capacity to retain leaf water, a phenotype associated with reduced cutin deposition and a thin cuticle. Map-based cloning revealed that Eibi1 encodes an HvABCG31 full transporter. The gene was highly expressed in the elongation zone of a growing leaf (the site of cutin synthesis), and its gene product also was localized in developing, but not in mature tissue. A de novo wild barley mutant named "eibi1.c," along with two transposon insertion lines of rice mutated in the ortholog of HvABCG31 also were unable to restrict water loss from detached leaves. HvABCG31 is hypothesized to function as a transporter involved in cutin formation. Homologs of HvABCG31 were found in green algae, moss, and lycopods, indicating that this full transporter is highly conserved in the evolution of land plants.

The taxonomic status of a nitrogen-fixing bacterium, strain MSSRF38(T), isolated from the rhizosphere of mangrove-associated wild rice (Porteresia coarctata Tateoka), in Pichavaram, India, was studied using a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the novel strain MSSRF38(T) was most closely related to Vibrio ruber DSM 16370(T) (98.3% gene sequence similarity), Vibrio rhizosphaerae DSM 18581(T) (98.2% sequence similarity) and <96% to the remaining Vibrio species. Multilocus sequence analysis using ftsZ, gapA, gyrB and mreB genes showed low levels of gene sequence similarities (82-90%) with all species of the genus Vibrio with validly published names, indicating that strain MSSRF38(T) occupies a distinct phylogenetic position. DNA-DNA hybridization experiments showed that strain MSSRF38(T) had <70% DNA-DNA similarity to its closest neighbours V. ruber DSM 16370(T) (27.4%) and V. rhizosphaerae DSM 18581(T) (12.1%). Strain MSSRF38(T) could be differentiated from its relatives on the basis of several phenotypic characteristics. The major fatty acids were feature 3 (including C(16:1omega)7c and/or C(15:0) iso 2-OH), C16:0, C(18:1omega)7c, C(14:0) and C(12:0). The DNA G+C content was 45.4 mol%. Based on genotypic, phenotypic, chemotaxonomic and DNA-DNA analyses, the name Vibrio mangrovi sp. nov. (type strain MSSRF38(T)=LMG 24290(T)=DSM 19641(T)) is proposed for this novel taxon.

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)omega7c and/or iso-C(15 : 0) 2-OH and C(18 : 1)omega7c, 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)).

Two facultatively anaerobic, nitrogen-fixing bacteria (strains MSSRF30(T) and MSSRF31) were isolated from a mangrove-associated wild rice (Porteresia coarctata Tateoka). These strains were determined to be nitrogen-fixers using the acetylene reduction assay and by PCR detection of a nifH gene amplicon. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the novel strains were most closely related to Vibrio fluvialis LMG 7894(T) (96.8 % gene sequence similarity), Vibrio furnissii LMG 7910(T) (96.8 % sequence similarity) and Vibrio tubiashii CIP 102760(T) (96.7 % sequence similarity). Further multilocus sequence analysis using recA, pyrH, rpoA and nifH genes also showed low levels of sequence similarities (83-93 %) with all species of the genus Vibrio with validly published names. A multigene phylogenetic tree using concatenated sequences of the four genes (16S rRNA, rpoA, recA and pyrH) showed that strains MSSRF30(T) and MSSRF31 occupied a distinct phylogenetic position, forming a long branching that was not clustered with any other recognized Vibrio species. The fatty acid profile also suggested that the novel strains belonged to the genus Vibrio. The results of physiological and biochemical tests, genomic fingerprinting and DNA-DNA hybridization analyses clearly differentiated both novel strains from their closest phylogenetic neighbours, Vibrio cholerae IID6019, Vibrio mimicus LMG 7896(T), V. fluvialis LMG 7894(T) and V. furnissii LMG 7910(T). Several phenotypic traits enabled the differentiation of strain MSSRF30(T) from other species of the genus Vibrio. The DNA G+C content of strain MSSRF30(T) was 44.4+/-3.1 mol%. Based on genotypic, phenotypic, chemotaxonomic, phylogenetic and DNA-DNA hybridization analyses, the name Vibrio porteresiae sp. nov. (type strain MSSRF30(T)=LMG 24061(T)=DSM 19223(T)) is proposed for this novel taxon.

A study was conducted to understand the complexity of bacterial diversity of rhizosphere of Porteresia coarctata based on culture dependent method. A large number of bacteria were isolated on nutrient agar medium supplemented with 1% NaCl and the dominant ones were further analyzed with PCR-RFLP method. The sequence analyses of the dominant strains revealed that most of the sequences belonged to members of gamma proteobacteria, firmicutes, bacteroidetes and uncultured bacteria. The phylogenetic analysis of 16S rRNA gene sequences revealed close relationships to a wide range of clones or bacterial species of various divisions. These results afford an understanding of the role of rhizobacteria in alleviating salt stress in Porteresia coarctata expected to contribute towards long-term goal of improving plant-microbe interactions for salinity affected fields., ((c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Two novel red-pigmented Vibrio strains, MSSRF3(T) and MSSRF10, with antibacterial activity against phytopathogens were isolated from the rhizosphere region of mangrove-associated wild rice (Porteresia coarctata Tateoka), in Pichavaram, India. The cells were Gram-negative, facultatively anaerobic and rod-shaped and were motile by means of single polar flagella. The two strains were catalase-positive and oxidase-negative, and were able to grow in 0.1-10 % NaCl (with optimum growth in 2 % NaCl) and at temperatures of 20-42 degrees C (optimum growth at 25-30 degrees C). Both strains produced acid and gas from D-glucose under anaerobic conditions and utilized a wide range of compounds as sole carbon and energy sources. The DNA G+C contents determined were 51.3 mol% for strain MSSRF3(T) and 51.0 mol% for strain MSSRF10. Phylogenetic analysis based on 16S rRNA, rpoA, recA and pyrH gene sequences showed that strains MSSRF3(T) and MSSRF10 belong to the genus Vibrio and are very closely related to Vibrio ruber JCM 11486(T), with which they share 98.3-98.5 % (16S rRNA), 98.3-99.7 % (rpoA), 90.2-99.8 % (recA) and 91.3-99.4 % (pyrH) gene sequence similarities, respectively. Levels of DNA-DNA relatedness were 44 % between strains MSSRF3(T) and MSSRF10, 80 % between strain MSSRF10 and V. ruber JCM 11486(T) and 45 % between strain MSSRF3(T) and V. ruber JCM 11486(T). Strain MSSRF3(T) was phenotypically similar to V. ruber JCM 11486(T). However, the inability to reduce nitrate to nitrite, the ability to grow in 0.1 % NaCl and the presence of caseinase were characteristics that allowed differentiation between V. ruber JCM 11486(T) and strain MSSRF3(T). In addition, strain MSSRF3(T) could be differentiated from strain MSSRF10 and its closest relative V. ruber JCM 11486(T) with respect to its genomic fingerprinting analysis (random amplified polymorphic DNA, GTG5, BOX, PCR-restriction fragment length polymorphism and ribotyping). Therefore, based on phenotypic, genotypic, phylogenetic and DNA-DNA hybridization analyses, strain MSSRF3(T) (=LMG 23790(T)=DSM 18581(T)) should be classified as representing the type strain of a novel species of the genus Vibrio, for which the name Vibrio rhizosphaerae sp. nov. is proposed.

A novel salt-tolerant, N2-fixing and phosphate-solubilizing, Gluconacetobacter sp. (PA12) tagged with gusA gene, colonized Porteresia coarctata (wild rice) and Pokkali (salt-tolerant variety) more intensively when compared to Ponni (salt-sensitive variety). This was confirmed using a colony-counting method.