DIFFERENTIATION OF ERWINIA SPECIES IN THE HERBICOLA GROUP BY CLASS ANALYSIS OF CELLULAR FATTY-ACIDS

Profiles of cellular fatty acids of Erwinia herbicola, E. ananas, E. s tewartii and E. uredovora, comprising the Herbicola group in the genus Erwinia, contained 7 major components accounting for 90-95% of total fatty acids, and 30 minor components, each less than 1% of the total. The major components and their average percentage ranges in cells on K ing's medium B at 28-degrees-C for 1 day were: 12 : 0 (3.5-4.5%), 14 : 0 (3.6-4.3%), 16 : 0 (28.1-35.7%), 16 : 1 (17.5-24.2%), 18 : 1 (13.9- 31.9%), 3-OH 14 : 0 (4.6-7.2%) and cyclopropane 17 : 0 (trace levels i n E. stewartii, 5.0-6.7% in other species). Fatty acid composition cha nged as a function of physiological age of the cells. The regression c oefficient (b) as a function of age for percentage of saturated even- and odd-carbon, straight-chain fatty acids (Classes A and B) was eithe r negative or not significant for E. ananas and positive for the other species. A series of dichotomous steps was constructed based on fatty acid algorithms to differentiate all four species.