Nocardioides zeae sp. nov., isolated from the stem of Zea mays

Abstract

A Gram-stain-positive aerobic organism, isolated from the healthy stem of a Zea mays plant was studied for its taxonomic position. Based on 16S rRNA gene sequence analysis strain JM-1068(T) was most closely related to Nocardioides alkalitolerans (97.2%). The 16S rRNA gene sequence similarity to all other species of the genus Nocardioides was ≤ 96.1%. The quinone system of strain JM-1068(T) contained the major menaquinone MK-8(H4). The diagnostic diamino acid of the peptidoglycan was LL-diaminopimelic acid. In the polar lipid profile, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and two unidentified phospholipids were predominant. The polyamine pattern contained predominantly spermidine and spermine. The fatty acid profile was composed of iso-C16 : 0 and C18 : 1ω9c in addition to C16 : 0, C17 : 0 and C17 : 1ω8c and low amounts of C16 : 0 2-OH and C17 : 0 2-OH. This supported the allocation of the strain to the genus Nocardioides. In addition, the results of physiological and biochemical tests also allowed phenotypic differentiation of strain JM-1068(T) from N. alkalitolerans. It is concluded that JM-1068(T) represents a novel species of the genus Nocardioides, for which we propose the name Nocardioides zeae sp. nov., with JM-1068(T) ( = CIP 110696(T) = LMG 28079(T)) as the type strain.