Acuticoccus kalidii sp. nov., a 1-aminocyclopropane-1-carboxylate (ACC) deaminase-producing endophyte from a root of Kalidium cuspidatum

Abstract

A 1-aminocyclopropane-1-carboxylate (ACC) deaminase-producing, Gram-stain-negative, strictly aerobic, non-motile, yellow-reddish, oval-shaped bacterial strain, designated M5D2P5T, was isolated from a root of Kalidium cuspidatum, in Tumd Right Banner, Inner Mongolia, PR China. M5D2P5T grew at 10–40 °C (optimum 30–35 °C), pH 5.0–10.0 (optimum pH 8.0) and with 0–7% NaCl (optimum 3.0 %). The strain was positive for catalase and oxidase. The phylogenetic trees based on 16S rRNA gene sequences indicated that M5D2P5T clustered with Acuticoccus yangtzensis JL1095T, and shared 98.0, 97.3, 97.2, 96.9 and less than 96.9 % 16S rRNA gene similarities to A. yangtzensis JL1095T, Acuticoccus mangrovi B2012T, Acuticoccus sediminis PTG4-2T, Acuticoccus kandeliae J103T, and all the other type strains, respectively. However, the phylogenomic tree showed it clustered with A. kandeliae J103T. M5D2P5T contained Q-10 as the major respiratory quinone, as well as two minor respiratory quinones, Q-7 and Q-8. Its major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified phospholipid, an unidentified glycolipid, and four unidentified lipids. The genomic DNA G+C content was 66.5 %. The digital DNA–DNA hybridization score and the average nucleotide identity based on blast values of M5D2P5T to A. yangtzensis JL1095T, A. kandeliae J103T, A. mangrovi B2012T, and A. sediminis PTG4-2T, were 20.8, 23.7, 20.7, and 21.5 %, and 73.3, 79.5, 74.4, and 73.7 %, respectively. The phylogenetic and phenotypic characteristics allowed the discrimination of M5D2P5T from its phylogenetic relatives. The novel species Acuticoccus kalidii sp. nov. is therefore proposed, and the type strain is M5D2P5T (=CGMCC 1.19149T=KCTC 92132T).