Two isolates from rhizosphere soil of cotton, designated Gh-67^Tand Gh-48^T, which produced large amounts of extracellular polysaccharide and possessed plant-growth-promoting traits, were characterized phenotypically and genotypically. The strains were Gram-negative and cells were non-motile rods that grew optimally at 28 °C and grew between pH 4 and 7. 16S rRNA gene sequence analysis of strains Gh-67^Tand Gh-48^Tplaced them in the genusMucilaginibacter, with pairwise sequence similarity between them and type strains from related genera ranging from 93.9 to 98.2 %. The major fatty acids were iso-C_15 : 0, C_16 : 0and summed feature 3 (C_16 : 1ω7c and/or iso-C_15 : 02-OH). The strains contained MK-7 as the major isoprenoid quinone. The DNA G+C contents of strains Gh-67^Tand Gh-48^Twere 46.7 and 44.2 mol%, respectively. The low DNA–DNA hybridization value (18 %) and a number of phenotypic differences between strains Gh-48^Tand Gh-67^Tindicated that they represent two separate species. Results of phenotypic, phylogenetic and genotypic analysis revealed that the strains were separated from the species ofMucilaginibacterdescribed to date. Therefore, strains Gh-67^Tand Gh-48^Trepresent novel species ofMucilaginibacter, for which we propose the namesMucilaginibacter gossypiisp. nov. (type strain Gh-67^T=NCIMB 14470^T=KCTC 22380^T) andMucilaginibacter gossypiicolasp. nov. (type strain Gh-48^T=NCIMB 14471^T=KCTC 22379^T).

Three novel bacterial strains, designated Vu-144^T, Vu-7 and Vu-35, were isolated on minimal medium from rhizosphere soil of field-grown cowpea and subjected to a taxonomic study using a polyphasic approach. Cells of the strains were Gram-stain-negative, non-motile, non-spore-forming, coccoid rods, and formed non-pigmented colonies. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Vu-144^T was affiliated with an uncultivated lineage of the phylum Bacteroidetes . Its closest phylogenetic neighbour was the recently described species Niastella populi , a member of the family Chitinophagaceae , with just 90.7 % sequence similarity to the type strain. The only isoprenoid quinone detected was menaquinone 7 (MK-7). The fatty acid profiles showed large amounts of iso-C_15 : 0, iso-C_17 : 0 3-OH and iso-C_15 : 1 G and minor amounts of summed feature 3 (C_16 : 1ω7c and/or iso-C_15 : 0 2-OH), C_16 : 0 and other fatty acids, allowing the differentiation of the strains from other genera. The G+C content of the genomic DNA of the three strains ranged from 43.1 to 44.3 mol%. In addition to phosphatidylethanolamine, the major polar lipids were three unidentified aminophospholipids (APL1–APL3), two unidentified phospholipids (PL1, PL2) and three unidentified lipids (UL1–UL3). Biochemical test patterns also differed from those of Niastella populi and members of other genera. All three isolates showed plant-growth-promoting properties, e.g. the ability to produce indole-3-acetic acid and NH₃ and to solubilize phosphate, utilized 1-aminocyclopropane 1-carboxylate (ACC) as a sole source of nitrogen and possessed the ACC deaminase enzyme. The novel isolates readily colonized roots and stimulated growth of tomato and cowpea under glasshouse conditions. Inoculated plants showed a 45–60 % increase in dry matter weight with respect to uninoculated controls. On the basis of the evidence from our polyphasic study, isolate Vu-144^T represents a novel genus and species in the family Chitinophagaceae , for which the name Arachidicoccus rhizosphaerae gen. nov., sp. nov. is proposed. The type strain of Arachidicoccus rhizosphaerae is Vu-144^T ( = KCTC 22378^T = NCIMB 14473^T).

Aims: The aim of this study was to isolate and characterize new bacteriophages that infect a wide range of plant pathogenic Ralstonia solanacearum strains. Methods and Results: Fifteen bacteriophages were isolated from pepper, tomato and tobacco plant rhizospheres infected with R. solanacearum. A host specificity analysis of the isolated phages using nine strains of R. solanacearum indicated great phage diversity in a single soil. Two phages, PE226 and TM227, showed clear plaques on all nine bacterial hosts tested and were virtually identical in morphology and genome. PE226, an Inovirus, is a long, flexible, filamentous phage carrying a circular (+) sense single‐strand DNA genome of 5475 nucleotides. DNA sequences of PE226 exhibited nine open reading frames (ORF) that were not highly similar to those of other phages infecting R. solanacearum. The genome organization of PE226 was partially similar to that of p12J of Ralstonia pickettii. One ORF of PE226 showed identity to the zot gene encoding zonula occludens toxin of Vibrio cholera. Orf7 of PE226 was also present in the genome of R. solanacearum strain SL341. However, SL341, a highly virulent strain in tomato, was still sensitive to phage PE226. Conclusions: A new, flexible, filamentous phage PE226 infected wide range of R. solanacearum strains and carried unique circular single‐strand DNA genome with an ORF encoding Zot‐like protein. Significance and Impact of the Study: PE226 may be a new type of temperate phage, based on its lytic nature on a wide range of hosts and the presence of a zot homologue in a host bacterial genome.

The occurrence and role of endophytic bacterial communities in banana under different field-grown conditions have not yet been explored. Hence, a survey was conducted in five different banana cultivars – Rasthali, Hill banana, Co1, Nattu Poovan and Red banana – for the assessment of bacterial endophytes grown in Tamil Nadu, Southern India. From 352 endophytes isolated, 17 were selected based on distinct morpho-physiological characters. The 17 selected isolates were grouped into eight different genera, which belong to the phyla Actinobacteria, Firmicutes and Proteobacteria, with remarkable differences in the bacterial compositions among the banana cultivars. Higher bacterial diversity was observed in Rasthali and Red banana when compared to Co1 and Nattu Poovan. Isolates exhibited at least one functional plant growth-promoting trait when tested for siderophore production and indole-3-acetic acid (IAA) synthesis. Representative isolates from eight different genera were further analyzed for plant–microbe interactions. A seedling inoculation experiment on tomato showed a significant effect on seed germination, seedling growth, vigor index, and biomass production compared to the uninoculated control. However, a comprehensive approach is needed to evaluate the full potential of bacterial endophytes to improve quality and yield in banana under field conditions.