Frankia asymbiotica sp. nov., a non-infective actinobacterium isolated from Morella californica root nodule.

The taxonomic status of strain M16386, a nitrogen-fixing but non-nodulating isolate from Morella californica, was established on the basis of a polyphasic approach. The strain grows as branched hyphae, with vesicles and non-motile productive multilocular sporangia. It metabolizes short fatty acids, TCA cycle intermediates and carbohydrates as carbon sources, and fixes nitrogen in the absence of combined nitrogen source in the growth media. Chemotaxonomic traits of strain M16386 are consistent with its affiliation to the genus Frankia. The characteristic diamino acid in the cell wall is meso-diaminopimelic acid. Strain M16386 contains phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol, glycophospholipid and phospholipid as polar lipids; MK-9(H4) and MK-9(H6) as the predominant menaquinones; iso-C16 : 0 and C17 : 1ω8c as major fatty acids; and galactose, glucose, mannose, rhamnose and ribose as whole-cell sugars. Strain M16386 showed 98.2 % 16S rRNA gene sequence similarity with its closest phylogenetic neighbour, Frankia inefficaxDSM 45817. Based on these results, strain M16386 (=DSM 100626=CECT 9040) is designated the type strain of a novel species of the genus Frankia,for which the name Frankia asymbiotica sp. nov. is proposed.