Pseudonocardia tritici sp. nov., a novel actinomycete isolated from rhizosphere soil of wheat (Triticum aestivum L.).

Abstract

An aerobic, non-motile, Gram-stain positive actinomycete, designated strain NEAU-YY211T, was isolated from the rhizosphere soil of wheat (Triticum aestivum L.) collected from Zhumadian, Henan Province, mid-eastern China, and characterised taxonomically using a polyphasic approach. Comparative analysis of the 16S rRNA gene sequence indicated that strain NEAU-YY211T belongs to the genus Pseudonocardia, showing high similarities with respect to Pseudonocardia ammonioxydans H9T (99.1%) and Pseudonocardia antitumoralis SCSIO 01299T (99.0%), respectively. The cell wall was found to contain meso-diaminopimelic acid and the whole cell sugars were identified as arabinose and galactose. The predominant menaquinone of strain NEAU-YY211T was identified as MK-8(H4) and the major fatty acids were identified as iso-C16:0, C17:1ω8c and iso-C16:1. The phospholipid profile was found to consist of diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, phosphatidylinositol and an unidentified phospholipid. The G+C content of the genomic DNA was determined to be 72.6mol%. Levels of DNA-DNA relatedness with P. ammonioxydans JCM 12462T and P. antitumoralis DSM 45322T were 54.5 ± 3.5% and 49.8 ± 2.5% (mean ± SD), respectively. Based on phylogenetic analysis, phenotypic and genotypic data, it is concluded that the isolate can be distinguished from closely related type strains and thus represents a novel species of the genus Pseudonocardia, for which the name Pseudonocardia tritici sp. nov. is proposed. The type strain is NEAU-YY211T (= DSM 106068T = CGMCC 4.7474T).