Rhizobialide: A new stearolactone produced by Mesorhizobium sp CCNWGX022, a rhizobial endophyte from Glycyrrhiza uralensis

The endophytic strain Mesorhizobium sp. CCNWGX022 was isolated from licorice (Glycyrrhiza uralensis FISCH.) grown in the and and semi-arid regions of Northwest China. The new stearic acid derived gamma-lactone 1, named rhizobialide (=(5S)-4,5-dihydro-5-(8-oxotetradecyl)furan-2(3H)-one), was isolated from the petroleum-ether extract of the fermentation broth of this strain. The structure of I was elucidated on the basis of spectroscopic and mass-spectrometric analysis. This is the first report of this type of compound from rhizobia.