Pseudoalteromonas rhizosphaerae Sp. Nov. , a novel plant growth-promoting bacterium with potential use in phytoremediation

17 páginas, 2 figuras, 3 tablas

Strain RA15T was isolated from the rhizosphere of the halophyte plant Arthrocnemum macrostachyum growing in the Odiel marshes (Huelva, Spain). RA15T cells were Gram stain-negative, non-spore-forming, aerobic rods and formed cream-coloured, opaque, mucoid, viscous, convex, irregular colonies with an undulate margin. Optimal growth conditions were observed on tryptic soy agar (TSA) plates supplemented with 2.5 % NaCl (w/v) at pH 7.0 and 28 °C, although it was able to grow at 4–32 °C and at pH values of 5.0–9.0. The NaCl tolerance range was from 0 to 15 %. The major respiratory quinone was Q8 but Q9 was also present. The most abundant fatty acids were summed feature 3 (C16 : 1  ω7c and/or C16 : 1  ω6c), C17 : 1  ω8c and C16 : 0. The polar lipids profile comprised phosphatidylglycerol and phosphatidylethanolamine as the most abundant representatives. Phylogenetic analyses confirmed the well-supported affiliation of strain RA15T within the genus Pseudoalteromonas , close to the type strains of Pseudoalteromonas neustonica , Pseudoalteromonas prydzensis and Pseudoalteromonas mariniglutinosa . Results of comparative phylogenetic and phenotypic studies between strain RA15T and its closest related species suggest that RA15T could be a new representative of the genus Pseudoalteromonas , for which the name Pseudoalteromonas rhizosphaerae sp. nov. is proposed. The type strain is RA15T (=CECT 9079T=LMG 29860T). The whole genome has 5.3 Mb and the G+C content is 40.4 mol%.

This work has been possible thanks to Junta de Andalucía (P11-RNM-7274MO project) and INIA (RTA 2012–0006 C03-03 project).

Peer reviewed