Nocardioides zeicaulis sp. nov., an endophyte actinobacterium of maize

A Gram-stain-positive, aerobic organism was isolated as an endophyte from the stem tissue of healthy maize (Zea mays) and investigated in detail for its taxonomic position. On the basis of the 16S rRNA gene sequence analysis, strain JM-601T was shown to be most closely related to Nocardioides alpinus (98.3%), and Nocardioides ganghwensis (98.0%). The 16S rRNA gene sequence similarity to all other species of the genus Nocardioides was ≤ 98.0%. The diagnostic diamino acid of the peptidoglycan was ll-diaminopimelic acid. The major quinone of strain JM-601T was menaquinone MK-8(H4). The polar lipid profile revealed the major components diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylcholine and an unidentified phospholipid. The polyamine pattern contained predominantly spermine and moderate amounts of spermidine. In the fatty acid profile, iso-C16:0, C17:1ω8c and 10-methyl C17:0 were present in major amounts. All these data support the allocation of the strain to the genus Nocardioides. The results of physiological and biochemical characterization allow in addition a phenotypic differentiation of strain JM-601T from N. alpinus and N. ganghwensis. Strain JM-601T represents a novel species of the genus Nocardioides, for which we propose the name Nocardioides zeicaulis sp. nov., with JM-601T (=CCM 8654T=CIP 110980T) as the type strain.