Rhizobium capsici sp. nov., isolated from root tumor of a green bell pepper ( Capsicum annuum var. grossum) plant.

A novel, Gram-staining-negative, rod-shaped, aerobic and motile bacterium, designated strain CC-SKC2, was isolated from the root tumor of a green bell pepper ( Capsicum annuum var. grossum) plant in Taiwan. Cells were positive for oxidase and catalase activities and exhibited growth at 25-37 °C, pH 4.0-9.0 and tolerated NaCl concentrations up to 4.0 % (w/v). Strain CC-SKC2 is able to trigger nodulation in soybean ( Glycine max Merr.), but not in Capsicum annuum var. grossum, red bean ( Vigna angularis), sesbania ( Sesbania roxburghii Merr.) or alfalfa ( Medicago varia Martin.). The novel strain shared highest 16S rRNA gene sequence similarity to Rhizobium rhizoryzae KCTC 23652 and Rhizobium straminoryzae CC-LY845 (both 97.5 %) followed by Rhizobium lemnae L6-16 (97.3 %), Rhizobium pseudoryzae KCTC 23294 (97.1 %), and Rhizobium paknamense NBRC 109338 (97.0 %), whereas other Rhizobium species shared <96.7 % similarity. The DNA-DNA relatedness values of strain CC-SKC2 with R. rhizoryzae KCTC 23652, R. pseudoryzae KCTC 23294 and R. paknamense NBRC 109338 were 11.4, 17.2 and 17.0 %, respectively (reciprocal values were 11.1, 28.3 and 24.0 %, respectively). Phylogenetic analysis based on 16S rRNA, atpD and recA genes revealed a distinct taxonomic position attained by strain CC-SKC2 with respect to other Rhizobium species. The major fatty acids in strain CC-SKC2 were C, C cyclo ω8c, C 3-OH and/or C iso I and C ω7c and/or C ω6c. The polyamine pattern showed predominance of spermidine and moderate amounts of sym-homospermidine. The predominant quinone system was ubiquinone (Q-10) and the DNA G+C content was 60.5 mol%. On the basis of polyphasic taxonomic evidence presented here, strain CC-SKC2 is proposed to represent a novel species within the genus Rhizobium, for which the name Rhizobium capsici sp. nov. is proposed. The type strain is CC-SKC2 (=BCRC 80699 = JCM 19535). [ABSTRACT FROM AUTHOR]