Chryseobacterium phosphatilyticum sp. nov., a phosphate-solubilizing endophyte isolated from cucumber (Cucumis sativus L.) root

Abstract

A bacterial strain, designated as ISE14(T), with Gram-stain-negative and non-motile rod-shaped cells, was isolated from the root of a cucumber plant collected in a field in Iksan, Republic of Korea and was characterized using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain ISE14(T) represented a member of the genus Chryseobacterium and was closely related to Chryseobacterium viscerum 687B-08(T) (165 rRNA gene sequence similarity of 98.50 %), Chryseobacterium lactis NCTC 11390(T) (98.49 %), Chryseobacterium ureilyticum F-Fue-04LLLaaaa(T) (98.49 %) and Chryseobacterium oncorhynchi 701B-08(T) (98.04 %). Average nucleotide identity values between genome sequences of strain ISE14(T) and the closely related species ranged from 81.44 to 83.15 %, which were lower than the threshold of 95 % (corresponding to a DNA-DNA hybridization value of 70 %). The DNA G+C content of strain ISE14(T) was 36.3 mol%. The dominant fatty acids were iso-C-15:0, summed feature 9 (iso-C-17:1 omega 9c and/or C-16:0 10-methyl), summed feature 3 (iso-C-15:0 2-OH and/or C-16:1 omega 7c) and iso-C-17:0 3-OH. The major polar lipids were phosphatidylethanolamine, three unidentified aminolipids and eight unidentified lipids; the predominant respiratory quinone was MK-6. On the basis of the evidence presented in this study, strain ISE14(T) can be distinguished from closely related species belonging to the genus Chryseobacterium. Thus, strain ISE14(T) is a novel species of the genus Chryseobacterium, for which the name Chryseobacterium phosphatilyticum sp. nov. is proposed. The type strain is ISE14(T) (=KACC 19820(T)=JCM 32876(T)).