Paracoccus aeridis sp. nov., an indole-producing bacterium isolated from the rhizosphere of an orchid, Aerides maculosa.

A Gram-stain-negative, non-motile, coccoid-shaped, catalase- and oxidase-positive, non-denitrifying, neutrophilic bacterium designated as strain JC501^T was isolated from an epiphytic rhizosphere of an orchid, Aerides maculosa, growing in the Western Ghats of India. Phylogenetic analyses based on the 16S rRNA gene sequence indicated that strain JC501^T belonged to the genus Paracoccus and had the highest levels of sequence identity with Paracoccus marinus KKL-A5^T (98.9 %), Paracoccus contaminans WPAn02^T (97.3 %) and other members of the genus Paracoccus (<97.3 %). Strain JC501^T produced indole-3 acetic acid and other indole derivatives from tryptophan. The dominant respiratory quinone was Q-10 and the major fatty acid was C_{18 : 1}ω7c/C_{18 : 1}ω6c, with significant quantities of C_{18 : 1}ω9c, C_{17 : 0} and C_{16 : 0}. The polar lipids of strain JC501^T comprised phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, an unidentified glycolipid, two unidentified aminolipids, two unidentified lipids and four unidentified phospholipids. The genome of strain JC501^T was 3.3 Mbp with G+C content of 69.4 mol%. For the resolution of the phylogenetic congruence of the novel strain, the phylogeny was also reconstructed with the sequences of eight housekeeping genes. Based on the results of phylogenetic analyses, low (<85.9 %) average nucleotide identity, digital DNA-DNA hybridization (<29.8 %), chemotaxonomic analysis and physiological properties, strain JC501^T could not be classified into any of the recognized species of the genus Paracoccus. Strain JC501^T represents a novel species, for which the name Paracoccus aeridis sp. nov. is proposed. The type strain is JC501^T (=LMG 30532^T=NBRC 113644^T).