Paracoccus actinidiae sp.nov., a novel bacterium isolated from kiwi tree rhizosphere soil.

Abstract

Strain M09^T was isolated from the rhizoshere of kiwi fruit trees from an orchard located in Fangshan, Beijing, PR China (39° 49' 25.1″ N, 116° 4' 44.5″ E,). It is a short rod-shaped, Gram-stain-negative, facultatively anaerobic bacterium that tests positive for both oxidase and catalase. The strain exhibited growth within the temperature range of 15-45 °C (optimal growth at 30 °C) and the pH range of 4.0-10.0 (optimal growth at pH 7.0) and without NaCl. It also grew in a sodium chloride-free nutrient agar (NA) medium. The results of phylogenetic analysis of the 16S rRNA gene sequences indicated that M09^T represents a member of the genus Paracoccus and shares high similarity with Paracoccus everestensis S8-55^T (98.46%) and Paracoccus aerius 011410^T (97.58%). The average nucleotide identity values between M09^T and P. everestensis S8-55^T, P. aerius 011410^T, Paracoccus marinaquae X HP0099^T and Paracoccus fontiphilus MVW-1^T were 95.56, 84.51, 79.83 and 83.68%, respectively. The digital DNA-DNA hybridisation values between between M09^T and P. everestensis S8-55^T, P. aerius 011410^T, P. marinaquae X HP0099^T and P. fontiphilus MVW-1^T were 56.40, 29.30, 21.60 and 28.60%, respectively. The major fatty acids identified were C_10 : 0 3-OH (51.8%) and C_18 : 1ω7c (35.5%). The major respiratory quinone was Q-10, with Q-8 present as a minor component. Polar lipids were mainly comprised of diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylcholine (PC), and phosphatidylethanolamine (PE). Genome sequencing revealed that the strain has a DNA G+C content of 64.31 mol%. On the basis of this comprehensive taxonomic characterisation data, M09^T represents a novel species within the genus Paracoccus and has been named Paracoccus actinidiae sp. nov. The type strain is designated as M09^T (=GDMCC 1.4157^T=KCTC 8143^T).