USE OF CELLULAR FATTY-ACIDS IN THE CHARACTERIZATION AND DIFFERENTIATION OF BACTERIAL LEAF STREAK PATHOGENS ON MILLET

Analyses of cellular fatty acids (FAs) were used to identify bacterial leaf streaking pathogen(s) infecting foxtail and pearl millet in Colo rado, USA. Isolates from both hosts were identified as unknown pathova r(s) of Xanthomonas campestris. To determine any similarity the most d iscriminatory FA profiles of the US isolates were compared with there of X. campestris. pv. pennamericanum infecting pearl millet in Africa and 11 other X. campestris pathovars infecting members of the Poaceae family. The US isolates were different from X. campestris. pv. penname ricanum and the other X. campestris pathovars but similar among themse lves. When a dendogram of the millet isolates was constructed with 35 other X. campestris pathovars, the different nature of the US isolates was further clarified. However, this evidence was not enough to give the American isolates a separate pathovar status.