Fatty acid methyl ester profiling of Californian Xylella fastidiosa strains

Xylella fastidiosa ssp. fastidiosa (Xff) is the causal agent of Pierce’s disease of grapevine, a management-intensive and potentially deadly disease. However, different stains and other subspecies, such as Xylella fastidiosa ssp. multiplex (Xfm), exist in the same regions and vary in capacity to cause disease. All strains differ in the fatty acids that comprise cell membranes, as these would allow adaptations to specific host microenvironments. Therefore, studies were initiated to observe the fatty acid profiles of different Californian Xf isolates via fatty acid methyl ester (FAME) analysis. Observations revealed that the four Xff strains had similar FAME profiles that were distinct from those of the three Xfm strains, even in isolates that originated from the same host plant species. These data show consistent differences between Xff and Xfm strains, and demonstrate the potential that FAME profiling has for Xylella subspecies identification of novel isolates.