Xylella fastidiosa causes several plant diseases of economic importance such as citrus (Citrus spp.) variegated chlorosis (CVC), Pierce's disease of grapevine (Vitis vinifera) and leaf scorch of plum (Prunus salicina) and coffee (Coffea arabica). The nucleotide sequence of the genomic fragment, specific to Xylella fastidosa, amplified by the pair of primers RST 31/33, was determined for 38 isolates from citrus and for isolates from grapevine, coffee and plum in order to assess the level of sequence polymorphism of this fragment among isolates, as well as its genomic identity. Sequence polymorphism was not observed among isolates from citrus, but was detected among isolates from citrus and from grapevine, coffee and plum. The presence of a RsaI restriction site, which distinguishes isolates from citrus and grapevine from plum and other arboreal species, was identified in a North American isolate from plum but not in a Brazilian one.
