CELLULAR FATTY-ACID COMPOSITION OF 9 PATHOVARS OF XANTHOMONAS-CAMPESTRIS

Cellular fatty acids of 80 strains of Xanthomonas campestris, represen ting 9 different pathovars, were analyzed by gas-liquid chromatography and mass spectrometry. A total of 48 fatty acids were identified, the most important being the 16 : 0 (averaging at least 4.5 % of the tota l), the cis- and trans-9 16 : 1 (over 14.4 %), and the iso and anteiso 15 : 0 (over 30 %). Other major fatty acids (averaging over 1 % of to tal) were the saturated 14 : 0 and 15 : 0, the hydroxy-substituted iso 3-OH 11 : 0, 3-OH 12 : 0 and iso 3-OH 13 : 0, and the branch-chained iso 11 : 0, iso 16 : 0, iso 17 : 1, iso 17 : 0 and anteiso 17 : 0. Of 33 minor fatty acids detected and identified, only 7 have been previou sly reported in the xanthomonads. Significant differences in mean perc entages of 5 major fatty acids and 4 (chemical) class totals were dete cted among pathovars, which statistically segregated into three groups by rank analysis. X. campestris pv. dieffenbachiae was in a group by itself; pvs. campestris, citri (pathotypes A and B), manihotis, phaseo li, pruni and vesicatoria were in a seond group, and pvs. glycines, be gonia and citri (pathotype E) were in a third.