Publications by authors named "Jeffrey K Schachterle"

Xanthomonas translucens causes the disease bacterial leaf streak in several cereal crops and grasses. Here, we report the complete genome sequences of two isolates of X. translucens pv.

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The enterobacterial pathogen Erwinia amylovora uses multiple virulence-associated traits to cause fire blight, a devastating disease of apple and pear trees. Many virulence-associated phenotypes have been studied that are critical for virulence and pathogenicity. Despite the in vitro testing that has revealed how these systems are transcriptionally regulated, information on when and where in infected tissues these genes are being expressed is lacking.

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Members of the species complex cause a variety of wilting diseases across a wide range of hosts by colonizing and blocking xylem vessels. Of great concern are race 3 biovar 2 strains of capable of causing brown rot of potato at cool temperatures, which are select agents in the United States. To gain a better understanding of cool-virulence mechanisms, we generated libraries of transposon mutants in the cool-virulent strain UW551 and screened 10,000 mutants using our seedling assay for significantly reduced virulence at 20°C.

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Ralstonia solanacearum species complex strains are the causative agents for wilting diseases of many plants, including the economically important brown rot of potato. We developed a high-throughput virulence screen that is implemented in 96-well microtiter plates using seedlings grown in soft water agar to save space, effort, and resources. Nicotiana glutinosa was determined to be the most effective host for this assay, and we confirmed bacterial growth and systemic spread in inoculated seedlings.

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Fire blight, caused by the bacterial phytopathogen , is an economically important and mechanistically complex disease that affects apple and pear production in most geographic production hubs worldwide. We compile, assess, and present a genetic outlook on the progression of an infection in the host. We discuss the key aspects of type III secretion-mediated infection and systemic movement, biofilm formation in xylem, and pathogen dispersal via ooze droplets, a concentrated suspension of bacteria and exopolysaccharide components.

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Erwinia amylovora is the causative agent of the devastating disease fire blight of pome fruit trees. After infection of host plant leaves at apple shoot tips, E. amylovora cells form biofilms in xylem vessels, restrict water flow, and cause wilting symptoms.

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, causative agent of fire blight disease of apple and pear trees, has evolved to use small RNAs for post-transcriptional regulation of virulence traits important for disease development. The sRNA ArcZ regulates several virulence traits, and to better understand its roles, we conducted a transcriptomic comparison of wild-type and Δ mutant . We found that ArcZ regulates multiple cellular processes including genes encoding enzymes involved in mitigating the threat of reactive oxygen species (, , ), and that the Δ mutant has reduced catalase activity and is more susceptible to exogenous hydrogen peroxide.

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To successfully infect plant hosts, the collective regulation of virulence factors in a bacterial pathogen is crucial. Hfq is an RNA chaperone protein that facilitates the small RNA (sRNA) regulation of global gene expression at the post-transcriptional level. In this study, the functional role of Hfq in a broad host range phytopathogen was determined.

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causes the devastating fire blight disease of apple and pear trees. During systemic infection of host trees, pathogen cells must rapidly respond to changes in their environment as they move through different host tissues that present distinct challenges and sources of nutrition. Growing evidence indicates that small RNAs (sRNAs) play an important role in disease progression as posttranscriptional regulators.

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Toxin-antitoxin (TA) systems are genetic elements composed of a protein toxin and a counteracting antitoxin that is either a noncoding RNA or protein. In type I TA systems, the antitoxin is a noncoding small RNA (sRNA) that base pairs with the cognate toxin mRNA interfering with its translation. Although type I TA systems have been extensively studied in and a few human or animal bacterial pathogens, they have not been characterized in plant-pathogenic bacteria.

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Erwinia amylovora, the causative agent of fire blight disease of apple and pear trees, causes disease on flowers by invading natural openings at the base of the floral cup. To reach these openings, the bacteria use flagellar motility to swim from stigma tips to the hypanthium and through nectar. We have previously shown that the Hfq-dependent sRNAs ArcZ, OmrAB and RmaA regulate swimming motility in E.

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The formation of biofilms by () and requires the genes, which direct production of a polysaccharide extracellular matrix (Hms-ECM). Despite possessing identical sequences, produces much less Hms-ECM than . The regulatory influences that control Hms-ECM production and biofilm formation are not fully understood.

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