Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2005
Publication Date: 6/1/2006
Citation: Montero-Astua, M., Hartung, J.S., Li, W., Auilar, E., Chacon, C., Rivera, C. 2006. Variability in colony morphology of xylella fastidiosa isolates from costa rica. American Phytopathological Society. 96(6):S164
Technical Abstract: Xylella fastidiosa Wells is a xylem limited bacterium responsible for horticultural diseases such as Pierce’s disease of grapevines, citrus variegated chlorosis (CVC) and coffee leaf scorch (CLS). Different growth rates and colony morphologies have been described since the initial isolation of X. fastidiosa. Isolates of X. fastidiosa from different hosts from the USA and Costa Rica presented various morphologies on PW plates. A particular colony morphology was not consistently associated with a specific isolate, and on occasions colonies with two distinct morphologies grew on the same plate. Subcultures of a specific colony morphology sometimes produced colonies with different morphologies. Despite morphological differences, the colonies showed similar growth rates, becoming visible between day seven and nine after streaking. To confirm that all morphologies correspond to X. fastidiosa, single colonies from several isolates were analyzed with specific primers for X. fastidiosa (272-1-int/272-2-int). Moreover, some representative colonies were amplified with universal primers (FD1/RP1) for the bacterial 16S rDNA subunit and the amplification products were digested with restriction enzymes (Hinf I, Taq I, Sau3A I, Hae III, Alu I). All of the isolates produced the expected PCR product for X. fastidiosa. The 16S rDNA products presented the same pattern of digestion, except for DNA samples from a plum and an oak isolate used as controls. Our data suggest that pure cultures of X. fastidiosa present variable colony morphologies in vitro. Conversion among morphologies was observed. The reasons for this behavior are not known.