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Four Gram-positive, aerobic, catalase- and oxidase-negative, rod-shaped, motile endophytic bacterial strains, designated NM3R9 T , NE1TT3, NE2TL11 and NE2HP2 T , were isolated from the inner tissues (leaf and stem) of Sphaeralcea angustifolia and roots of Prosopis laevigata . They were characterized using a polyphasic approach, which revealed that they represent two novel Microbacterium species. Phylogenetic analysis based on 16S rRNA gene sequencing showed that the species closest to NE2HP2 T was Microbacterium arborescens DSM 20754 T (99.6 %) and that closest to NM3R9 T , NE2TL11 and NE2TT3 was Microbacterium oleivorans NBRC 103075 T (97.4 %). The whole-genome average nucleotide identity value between strain NM3R9 T and Microbacterium imperiale DSM 20530 T was 90.91 %, and that between strain NE2HP2 T and M. arborecens DSM 20754 T was 91.03 %. Digital DNA-DNA hybridization showed values of less than 70 % with the type strains of related species. The polar lipids present in both strains included diphosphatidylglycerol, phosphatidylglycerol, glycolipids and unidentified lipids, whereas the major fatty acids included anteiso-C 15 : 0 , anteiso-C 17 : 0 , iso-C 16 : 0 and C 16 : 0 . Whole-cell sugars included mannose, rhamnose and galactose. Strains NM3R9 T and NE2HP2 T showed physiological characteristics different from those present in closely related Microbacterium species. According to the taxonomic analysis, both strains belong to two novel species. The name Microbacterium plantarum sp. nov. is proposed for strain NE2HP2 T (=LMG 30875 T =CCBAU 101117 T ) and Microbacterium thalli sp. nov. for strains NM3R9 T (=LMG 30873 T =CCBAU 101116 T ), NE1TT3 (=CCBAU 101114) and NE2TL11 (=CCBAU 101115).

Six actinobacterial strains isolated from diverse legume tissues collected in various locations in Spain were characterized to determine their taxonomic status. Using 16S rRNA gene sequencing, the strains were primarily identified as members of the genus Micromonospora with more than 99 % similarity. Digital DNA-DNA hybridization values and average nucleotide identities between the six strains and the nearest type strains confirmed that each strain represented a novel species. Genome sequences were analysed to infer their metabolic profiles, their potential to produce secondary metabolites and plant growth promoting features. Chemotaxonomic and physiological studies were carried out to complete the phenotypic characterization and to distinguish the new Micromonospora species. The genomic and phenotypic characterization of the Micromonospora strains strongly support their classification as representatives of new species with the following names: Micromonospora alfalfae sp. nov., Micromonospora cabrerizensis sp. nov., Micromonospora foliorum sp. nov., Micromonospora hortensis sp. nov., Micromonospora salmantinae sp. nov. and Micromonospora trifolii sp. nov., with the type strains MED01 T , LAH09 T , PSH25 T , NIE111 T , PSH03 T and NIE79 T , respectively.

Ten representative actinobacterial strains isolated from marine sediments collected worldwide were studied to determine their taxonomic status. The strains were previously identified as members of the genus Salinispora and shared >99 % 16S rRNA gene sequence similarity to the three currently recognized Salinispora species. Comparative genomic analyses resulted in the delineation of six new species based on average nucleotide identity and digital DNA-DNA hybridization values below 95 and 70 %, respectively. The species status of the six new groups was supported by a core-genome phylogeny reconstructed from 2106 orthologs detected in 118 publicly available Salinispora genomes. Chemotaxonomic and physiological studies were used to complete the phenotypic characterization of the strains. The fatty acid profiles contained the major components iso-C 16 : 0 , C 15 : 0 , iso- 17 : 0 and anteiso C 17 : 0 . Galactose and xylose were common in all whole-sugar patterns but differences were found between the six groups of strains. Polar lipid compositions were also unique for each species. Distinguishable physiological and biochemical characteristics were also recorded. The names proposed are Salinispora cortesiana sp. nov., CNY-202 T (=DSM 108615 T =CECT 9739 T ); Salinispora fenicalii sp. nov., CNT-569 T (=DSM 108614 T =CECT 9740 T ); Salinispora goodfellowii sp. nov., CNY-666 T (=DSM 108616 T =CECT 9738 T ); Salinispora mooreana sp. nov., CNT-150 T (=DSM 45549 T =CECT 9741 T ); Salinispora oceanensis sp. nov., CNT-138 T (=DSM 45547 T =CECT 9742 T ); and Salinispora vitiensis sp. nov., CNT-148 T (=DSM 45548 T =CECT 9743 T ).

A Gram-stain-positive, aerobic, non-motile, coccoid, arsenic-resistant actinobacterial strain, designated CM1E1 T , was isolated from the lateral root tissue of Prosopis laegivata grown on a mine tailing in San Luis Potosi, Mexico. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CM1E1 T was clustered closely with species of the genus Kocuria, and showed the highest sequence similarity of 98.7 % to Kocuria rhizophila TA68 T . The DNA G+C content of strain CM1E1 T was 74.5 mol% ( T m ). The major fatty acids were anteiso-C 15 : 0 , anteiso-C 17 : 0 and iso-C 15 : 0 . The peptidoglycan of the cell wall contained lysine and alanine. The major respiratory quinones were MK-7(H 2 ) and MK-8(H 2 ). On the basis of the phenotypic characterization, phylogenetic relationships and chemotaxonomic analyses, strain CM1E1 T represents a novel species of the genus Kocuria , for which the name Kocuria arsenatis sp. nov. is proposed. The type strain is CM1E1 T ( = CCBAU 101092 T  = HAMBI 3625 T  = LMG 28671 T ).

Two Gram-negative, aerobic, non-motile, rod-shaped bacterial strains, FH13T and FH23, representing a novel group of Rhizobium isolated from root nodules of Phaseolus vulgaris in Mexico, were studied by a polyphasic analysis. Phylogeny of 16S rRNA gene sequences revealed them to be members of the genus Rhizobium related most closely to 'Rhizobium anhuiense' CCBAU 23252 (99.7 % similarity), Rhizobium leguminosarum USDA 2370T (98.6 %), and Rhizobium sophorae CCBAU 03386T and others ( ≤ 98.3 %). In sequence analyses of the housekeeping genes recA, glnII and atpD, both strains formed a subclade distinct from all defined species of the genus Rhizobium at sequence similarities of 82.3-94.0 %, demonstrating that they represented a novel genomic species in the genus Rhizobium. Mean levels of DNA-DNA relatedness between the reference strain FH13T and the type strains of related species varied between 13.0 ± 2.0 and 52.1 ± 1.2 %. The DNA G+C content of strain FH13T was 63.5 mol% (Tm). The major cellular fatty acids were 16 : 0, 17 : 0 anteiso, 18 : 0, summed feature 2 (12 : 0 aldehyde/unknown 10.928) and summed feature 8 (18 : 1ω7c). The fatty acid 17 : 1ω5c was unique for this strain. Some phenotypic features, such as failure to utilize adonitol, l-arabinose, d-fructose and d-fucose, and ability to utilize d-galacturonic acid and itaconic acid as carbon source, could also be used to distinguish strain FH13T from the type strains of related species. Based upon these results, a novel species, Rhizobium acidisoli sp. nov., is proposed, with FH13T ( = CCBAU 101094T = HAMBI 3626T = LMG 28672T) as the type strain.