Croceifilum oryzae gen. nov., sp. nov., isolated from rice paddy soil

Abstract

A mesophilic, aerobic, Gram-stain-positive, filamentous bacterial strain, designated ZYf1a3T, was isolated from rice paddy soil in Japan. This strain grew on a solid medium with formation of substrate mycelium; endospores were produced singly along the mycelium. Formation of aerial mycelium was not observed on any of the media tested. This strain produced a characteristic saffron yellow soluble pigment. Cloned 16S rRNA gene sequences of strain ZYf1a3T yielded three different copies (similarity between the three sequences: 99.8–99.9 %). One of these sequences had one base deletion. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain ZYf1a3T belongs to an independent phylogenetic lineage of the family Thermoactinomycetaceae. The cell wall of strain ZYf1a3T contained meso-diaminopimelic acid, alanine and glutamic acid, but no characteristic sugars. It contained menaquinone 7 as the sole menaquinone. The major cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0.The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidyl-N-methylethanolamine and unidentified aminophospholipids. The DNA G+C content was 42.5 mol%. From phylogenetic analysis based on 16S rRNA gene sequences and phenotypic characteristics, this strain is considered to represent a novel species in a new genus, for which the name Croceifilum oryzae gen. nov., sp. nov. is proposed. The type strain of Croceifilum oryzae is ZYf1a3T ( = JCM 30426T = CCUG 66446T = DSM 46876T).