Effect of inoculation with various rhizobia strains on the fatty acid composition of peribacteroid and bacteroid membranes of the nodule symbiosomes

The fatty acid (FA) composition of bacteroid and peribacteroid membranes wa s studied in the symbiotic pairs differing in their nitrogen-fixing efficie ncy; the results are compared with the FA composition of plasmalemma and fr ee-living rhizobia. The experiments involved lupine plants inoculated with strains of Bradyrhizobium lupini 359a (Nod(+)Fix(+)) and 400 (Nod(+)Fix L) manifesting high and low nitrogen-fixing efficiency, respectively, and broa d bean plants inoculated with strains of Rhizobium leguminosarum 97 (Nod(+) Fix(+)) and 87 (Nod(+)Fix L) of high and low nitrogen-fixing efficiency, re spectively. We showed that the rhizobia of the strains 359a and 97 were abl e to form nodules with peribacteroid membranes containing FA mainly or excl usively of plant origin. These strains were able to develop effective symbi otic pairs with legume plants. The use of strains 400 and 87 resulted in th e formation of nodules with peribacteroid membranes containing typical bact erial (branched-chain) FAs; these strains were characterized by an ineffect ive symbiosis.