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ARS Home » Northeast Area » Frederick, Maryland » Foreign Disease-Weed Science Research » Research » Publications at this Location » Publication #146923
Title: XYLELLA FASTIDIOSA TAXONOMY

Author
item Schaad, Norman
item POSTNIKOVA, ELENA - UNIV. NEBRASKA
item FATMI, M. - VET. HASSAN II
item LACY, G. - VA POLYTECH. INST.
item CHANG, C. - UNIV. GEORGIA

Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2003
Publication Date: 6/1/2003
Citation: SCHAAD, N.W., POSTNIKOVA, E., FATMI, M., LACY, G., CHANG, C.J. XYLELLA FASTIDIOSA TAXONOMY. Phytopathology. 93:S76. 2003.

Interpretive Summary:

Technical Abstract: Xylella fastidiosa (Xf) is classified as a single species but genetic studies support multiple taxons. To clarify Xf taxonomy, we used DNA homology (S1nuclease procedure) and ITS sequencing to compare 26 strains from 10 hosts. Using stringent conditions (Tm-8 deg C), DNA homology revealed three taxons, with more than 70% homology. Taxon A (grape, alfalfa, maple, and two almond strains), taxon B (peach, elm, plum, wild grape, one almond, and sycamore strains), and taxon C (citrus strains) with mean homologies of 85, 82, and 87%, respectively. Mean reciprocal homologies between taxons A and B, A and C, and B and C, were 56, 39, and 46%, respectively. ITS results confirmed the same taxons; A and B, A and C, and B and C had similarities of 98.7, 97.9, and 99.2, respectively. Taxon A strains grow well on PD2 agar but B and C strains do not. Taxon B strains are susceptible to penicillin but resistant to carbenicillin and A strains are opposite. We propose taxons A, B, and C be named X. fastidiosa subsp. piercei, agglomeri, and idiotraposa, respectively.