Chromobacterium rhizoryzae sp. nov., isolated from rice roots

Abstract

A novel facultatively anaerobic, rod-shaped bacterium, designated LAM1188T, was isolated from the roots of rice (Oryzasativa) in Hubei Province. Cells of LAM1188T were Gram-stain-negative and motile. The temperature and pH ranges for growth were 15-40 °C (optimum: 30 °C) and pH 5-10 (optimum: pH 7), respectively. The strain did not require NaCl for growth but tolerated up to 3.5 % NaCl (w/v). Analysis of the 16S rRNA gene sequence indicated that the isolate represented a member of the genus Chromobacterium, and was most closely related to Chromobacterium haemolyticum MDA0585T and Chromobacterium aquaticum CC-SEYA-1T with 98.7 % and 97.3 % sequence similarity, respectively. The values of DNA-DNA hybridization between LAM1188T and C. haemolyticum JCM 14163T and C. aquaticum CCUG 55175T were 54.0±2.1 % and 44.0±1.2 %, respectively. The major cellular fatty acids were C16 : 0 and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). The main polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, four unidentified aminolipids and four unidentified lipids. The respiratory quinone was ubiquinone Q-8. The DNA G+C content was 64.1 mol% as determined by the Tm method. On the basis of its phenotypic, chemotaxonomic and phylogenetic characteristics, strain LAM1188T is suggested to represent a novel species of the genus Chromobacterium, for which the name Chromobacte riumrhizoryzae sp. nov. is proposed. The type strain is LAM1188T (=ACCC 19900T=JCM 31180T).