Hypervariations of a Protease-Encoding Gene, PD0218 ( pspB ), in Xylella fastidiosa Strains Causing Almond Leaf Scorch and Pierce's Disease in California
- 15 June 2008
- journal article
- Published by American Society for Microbiology in Applied and Environmental Microbiology
- Vol. 74 (12), 3652-3657
- https://doi.org/10.1128/aem.02386-07
Abstract
Xylella fastidiosa is a gram-negative plant pathogenic bacterium that causes almond leaf scorch disease (ALSD) and Pierce's disease (PD) of grape in many regions of North America and Mexico. Of the two 16S rRNA gene genotypes described in California, A genotype strains cause ALSD only and G genotype strains cause both PD and ALSD. While G genotype strains cause two different diseases, little is known about their genetic variation. In this study, we identified a putative protease locus, PD0218 ( pspB ), in the genome of X. fastidiosa and evaluated the variation at this locus in X. fastidiosa populations. PD0218 contains tandem repeats of ACDCCA, translated to threonine and proline (TP), upstream of the putative protease conserved domain. Among 116 X. fastidiosa ALSD and PD strains isolated from seven locations in California, tandem repeat numbers (TRNs) varied from 9 to 47, with a total of 30 TRN genotypes, indicating that X. fastidiosa possesses an active mechanism for contracting and expanding tandem repeats at this locus. Significant TRN variation was found among PD strains (mean = 29.9), which could be further divided into two TRN groups: PD-G small (mean = 17.3) and PD-G large (mean = 44.3). Less variation was found in ALSD strains (mean = 21.7). The variation was even smaller after ALSD strains were subdivided into the A and G genotypes (mean = 13.3, for the G genotype; mean = 27.1, for the A genotype). Genetic variation at the PD0218 locus is potentially useful for sensitive discrimination of X. fastidiosa strains. However, TRN stability, variation range, and correlation to phenotypes should be evaluated in epidemiological applications such as pathotype identification and delineation of pathogen origin.Keywords
This publication has 31 references indexed in Scilit:
- Variation in the Number of Tandem Repeats and Profile of Surface Protein Genes among Invasive Group B Streptococci Correlates with Patient AgeJournal of Clinical Microbiology, 2007
- Recombinant expression and characterization of aXylella fastidiosacysteine protease differentially expressed in a nonpathogenic strainFEMS Microbiology Letters, 2006
- Mechanisms of tandem repeat instability in bacteriaMutation Research, 2006
- Enterococcus faecalis Mammalian Virulence-Related Factors Exhibit Potent Pathogenicity in the Arabidopsis thaliana Plant ModelInfection and Immunity, 2005
- Draft Sequencing and Comparative Genomics of Xylella fastidiosa Strains Reveal Novel Biological InsightsGenome Research, 2002
- Genetic Diversity of Pierce's Disease Strains and Other Pathotypes of Xylella fastidiosaApplied and Environmental Microbiology, 2001
- CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choiceNucleic Acids Research, 1994
- Isolation and Preliminary Characterization of Extracellular Proteases Produced by Strains ofXylella fastidiosafrom GrapevinesPhytopathology®, 1994
- Etiological Role of the Xylem-Limited Bacterium Causing Pierce's Disease in Almond Leaf ScorchPhytopathology®, 1980
- Etiology of Almond Leaf Scorch Disease and Transmission of the Causal AgentPhytopathology®, 1976