PHOSPHOLIPID AND FATTY-ACID COMPOSITIONS OF RHIZOBIUM-LEGUMINOSARUM BIOVAR TRIFOLII ANU843 IN RELATION TO FLAVONE-ACTIVATED PSYM NOD GENE-EXPRESSION

The phospholipid and associated fatty acid compositions of the bacteri al symbiont of clover, Rhizobium leguminosarum biovar trifolii wild-ty pe ANU843, was analyzed by two-dimensional silica thin-layer chromatog raphy, fast atom bombardment-mass spectrometry, flame-ionization detec tion gas-liquid chromatography and combined gas-liquid chromatography/ mass spectrometry. The phospholipid composition included phosphatidyle thanolamine (15%), N-methylphosphatidylethanolamine (47%), N,N-dimethy lphosphatidylethanolamine (9%), phosphatidylglycerol(19%), cardiolipin (5%) and phosphatidylcholine (2%). Fatty acid composition included pr edominantly cis-11-octadecenoic acid, lower levels of cis-9-hexadeceno ic acid, hexadecanoic acid, 11-methyl-11-octadecenoic acid, octadecano ic acid, 11,12-methyleneoctadecanoic acid, eicosanoic acid and traces of branched, and di- and triunsaturated fatty acids. The influence of expression of the ''nodulation'' genes encoding symbiotic functions on the composition of these membrane lipids was examined in wild;type ce lls grown with or without the flavone inducer, 4',7-dihydroxyflavone a nd in mutated cells lacking the entire symbiotic plasmid where these g enes reside, or containing single transposon insertions in selected no dulation genes. No significant changes in phospholipid or associated f atty acid compositions were detected by the above methods of analysis.