Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2006
Publication Date: 7/29/2006
Citation: Chen, J., Groves, R.L., Civerolo, E.L. 2006. Variation of pspb (pd1208) locus among closely related xylella fastidiosa strains. [abstract]. Phytopathology. 96:S22
Technical Abstract: Xylella fastidiosa is a Gram negative plant pathogenic bacterium causing grape Pierce’s disease (PD) and almond leaf scorch disease (ALSD). Two distinct genotypes are associated with ALSD. A-genotype strains cause ALSD but not PD. G-genotype strains cause both ALSD and PD. However, little is known about intra-genotypic relationships. For example, it remains unclear how variable G-genotype strains isolated from the same, as well as the near-by, orchards or vineyards are. We identified a potential hyper-variable region in the locus of pspB (PD1208) encoding a putative serine protease. Calculated from the genome sequence of X. fastidosa strain Temecula, the N terminus of pspB is characterized by the presence of 22 tandem repeats of TP (threonine and proline). This converts to the tandem nucleotide repeat of [ACG(A)CCA]22. Analysis of sequences of PCR amplicons from 60 ALSD strains isolated from the same almond orchard using primers flanking the hyper-variable region showed a highly variable number of tandem repeats within each A- and G-genotype group.