| genetic analysis of a novel xylella fastidiosa subspecies found in the southwestern united states. | xylella fastidiosa, the causal agent of several scorch diseases, is associated with leaf scorch symptoms in chitalpa tashkentensis, a common ornamental landscape plant used throughout the southwestern united states. for a number of years, many chitalpa trees in southern new mexico and arizona exhibited leaf scorch symptoms, and the results from a regional survey show that chitalpa trees from new mexico, arizona, and california are frequently infected with x. fastidiosa. phylogenetic analysis of ... | 2009 | 19581467 |
| whole genome sequences of two xylella fastidiosa strains (m12 and m23) causing almond leaf scorch disease in california. | xylella fastidiosa is a gram-negative plant-pathogenic bacterium causing many economically important diseases, including almond leaf scorch disease (alsd) in california. genome information greatly facilitates research on this nutritionally fastidious organism. here we report the complete genome sequences of two alsd strains of this bacterium, m12 and m23. | 2010 | 20601474 |
| recent evolutionary radiation and host plant specialization in the xylella fastidiosa subspecies native to the united states. | the bacterial pathogen, xylella fastidiosa, infects many plant species in the americas, making it a good model for investigating the genetics of host adaptation. we used multilocus sequence typing (mlst) to identify isolates of the native u.s. subsp. multiplex that were largely unaffected by intersubspecific homologous recombination (ihr) and to investigate how their evolutionary history influences plant host specialization. we identified 110 "non-ihr" isolates, 2 minimally recombinant "intermed ... | 2013 | 23354698 |
| is vector control sufficient to limit pathogen spread in vineyards? | vector control is widely viewed as an integral part of disease management. yet epidemiological theory suggests that the effectiveness of control programs at limiting pathogen spread depends on a variety of intrinsic and extrinsic aspects of a pathosystem. moreover, control programs rarely evaluate whether reductions in vector density or activity translate into reduced disease prevalence. in areas of california invaded by the glassy-winged sharpshooter (homalodisca vitripennis germar), pierce's d ... | 2015 | 26313985 |
| seasonal abundance of draeculacephala minerva and other xylella fastidiosa vectors in california almond orchards and vineyards. | almond leaf scorch (als) disease is caused by the bacterium xylella fastidiosa and transmitted by xylem-feeding insects. reports of increased incidence of als-diseased trees in california prompted surveys in three almond [prunus dulcis (mill.) d. a. webb]-growing regions, from june 2003 to september 2005, to determine insect vector species composition and abundance. for comparison, sampling in and near vineyards in the san joaquin valley, california, also was completed. sampling in or near almon ... | 2011 | 21510181 |
| hypervariations of a protease-encoding gene, pd0218 (pspb), in xylella fastidiosa strains causing almond leaf scorch and pierce's disease in california. | 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 (p ... | 2008 | 18456854 |
| high throughput pcr detection of xylella fastidiosa directly from almond tissues. | xylella fastidiosa, the causal agent of almond leaf scorch disease (alsd), is currently re-emerging as a serious concern in california. efficient pathogen detection is critical for alsd epidemiological studies, particularly when a large sample size is involved. we here report a pcr procedure to detect x. fastidiosa directly from infected almond tissue without the laborious dna extraction. plant samples were prepared by freeze-drying and pulverized. appropriate dilutions of the pulverized freeze- ... | 2008 | 18295913 |
| initial genetic analysis of xylella fastidiosa in texas. | xylella fastidiosa is the causative agent of pierce's disease of grape. no published record of x. fastidiosa genetics in texas exists despite growing financial risk to the u.s. grape industry, a texas population of the glassy-winged sharpshooter insect vector (homalodisca vitripennis) now spreading in california, and evidence that the bacterium is ubiquitous to southern states. using sequences of conserved gyrb and mopb genes, we have established at least two strains in texas, grape strain and r ... | 2008 | 18172717 |
| spatial and temporal dynamics of overwintering homalodisca coagulata (hemiptera: cicadellidae). | a 4-yr landscape-scale study was conducted to investigate spatial and temporal dynamics of overwintering homalodisca coagulata (say) (hemiptera: cicadellidae) in the lower san joaquin valley, california. spatial structures of h. coagulata distributions were characterized with moran's i index, and spatial associations between h. coagulata and the surrounding environment were investigated with a geographic information system. h. coagulata was caught consistently with sticky traps throughout the wi ... | 2006 | 17195657 |
| effects of temperature on the flight activity of graphocephala atropunctata (hemiptera: cicadellidae). | graphocephala atropunctata (signoret) is the principal vector of xylella fastidiosa (wells, raju, hung, weisberg, mandelco-paul and brenner), the bacterium that causes pierce's disease of grapevine in coastal california. monitoring the activity of c. atropunctata in the early spring is important for timing insecticide sprays and assessing the potential for disease spread to adjacent vineyards. trapping studies with yellow sticky traps over 3 yr in napa valley, ca, established a significant corre ... | 2000 | 14658516 |
| dispersion of homalodisca coagulata (hemiptera: cicadellidae), a vector of xylella fastidiosa, into vineyards in southern california. | recent epidemics of pierce's disease of grapevine in california vectored by homalodisca coagulata (say), an invasive vector species, have characteristics that differ from epidemics involving native vectors. among these differences are the longer distances and greater speed that the disease is spread by h. coagulata. in this investigation, we used yellow sticky traps to study the seasonal dispersion activity of h. coagulata in a southern california grape-growing area in which an epidemic of pierc ... | 2003 | 14650508 |
| seasonal flight activity of two homalodisca species (homoptera: cicadellidae) that spread xylella fastidiosa in southern california. | homalodisca coagulata (say) and homalodisca lacerta (fowler) are vectors of a new bacterial disease of oleander in california known as oleander leaf scorch, induced by the bacterium xylella fastidiosa. h. coagulata also has been implicated in the spread of the strain of x. fastidiosa that induces pierce's disease of grapevines in california. we monitored the flight activity of h. coagulata and h. lacerta in oleander and citrus by using yellow sticky cards at three southern california locations w ... | 2001 | 11777056 |
| geographic distribution and relative abundance of the invasive glassy-winged sharpshooter: effects of temperature and egg parasitoids. | the capacity to predict the geographic distribution and relative abundance of invasive species is pivotal to developing policy for eradication or control and management. commonly used methods fall under the ambit of ecological niche models (enms). these methods were reviewed and shortcomings identified. weather-driven physiologically based demographic models (pbdms) are proposed that resolve many of the deficiencies of enms. the pbdm approach is used to analyze the invasiveness of the polyphagou ... | 2011 | 22251675 |
| an engineered innate immune defense protects grapevines from pierce disease. | we postulated that a synergistic combination of two innate immune functions, pathogen surface recognition and lysis, in a protein chimera would lead to a robust class of engineered antimicrobial therapeutics for protection against pathogens. in support of our hypothesis, we have engineered such a chimera to protect against the gram-negative xylella fastidiosa (xf), which causes diseases in multiple plants of economic importance. here we report the design and delivery of this chimera to target th ... | 2012 | 22355130 |
| large-scale intersubspecific recombination in the plant-pathogenic bacterium xylella fastidiosa is associated with the host shift to mulberry. | homologous recombination plays an important role in the structuring of genetic variation of many bacteria; however, its importance in adaptive evolution is not well established. we investigated the association of intersubspecific homologous recombination (ihr) with the shift to a novel host (mulberry) by the plant-pathogenic bacterium xylella fastidiosa. mulberry leaf scorch was identified about 25 years ago in native red mulberry in the eastern united states and has spread to introduced white m ... | 2014 | 24610840 |
| population structure of xylella fastidiosa associated with almond leaf scorch disease in the san joaquin valley of california. | xylella fastidiosa causes disease in many commercial crops, including almond leaf scorch (als) disease in susceptible almond (prunus dulcis). in this study, genetic diversity and population structure of x. fastidiosa associated with als disease were evaluated. isolates obtained from two almond orchards in fresno and kern county in the san joaquin valley of california were analyzed for two successive years. multilocus simple-sequence repeat (ssr) analysis revealed two major genetic clusters that ... | 2015 | 25807309 |
| a conjugative 38 kb plasmid is present in multiple subspecies of xylella fastidiosa. | a ≈ 38kb plasmid (pxf-riv5) was present in the riv5 strain of xylella fastidiosa subsp. multiplex isolated from ornamental plum in southern california. the complete nucleotide sequence of pxf-riv5 is almost identical to that of pxfas01 from x. fastidiosa subsp. fastidiosa strain m23; the two plasmids vary at only 6 nucleotide positions. blast searches and phylogenetic analyses indicate pxf-riv5 and pxfas01 share some similarity to chromosomal and plasmid (pxf51) sequences of x. fastidiosa subsp. ... | 2012 | 23251694 |
| modeling cold curing of pierce's disease in vitis vinifera 'pinot noir' and 'cabernet sauvignon' grapevines in california. | pierce's disease (pd) of vitis vinifera grapevines is caused by the bacterium xylella fastidiosa, a pathogen with a wide plant host range. exposure of x. fastidiosa-infected plant tissue to cold temperatures has been shown to be effective at eliminating the pathogen from some plant hosts such as grapevines. this "cold curing" phenomenon suggests itself as a potential method for disease management and perhaps control. we investigated cold therapy of pd-affected 'pinot noir' and 'cabernet sauvigno ... | 2011 | 22070280 |
| population genomic analysis of a bacterial plant pathogen: novel insight into the origin of pierce's disease of grapevine in the u.s. | invasive diseases present an increasing problem worldwide; however, genomic techniques are now available to investigate the timing and geographical origin of such introductions. we employed genomic techniques to demonstrate that the bacterial pathogen causing pierce's disease of grapevine (pd) is not native to the us as previously assumed, but descended from a single genotype introduced from central america. pd has posed a serious threat to the us wine industry ever since its first outbreak in a ... | 2010 | 21103383 |