Environmental alkalization suppresses deployment of virulence strategies in pv. DC3000.

Plant pathogenic bacteria encounter a drastic increase in apoplastic pH during the early stages of plant immunity. The effects of alkalization on pathogen-host interactions have not been comprehensively characterized. Here, we used a global transcriptomic approach to assess the impact of environmental alkalization on pv.

Analysis of soft rot population diversity in US potato growing regions between 2015 and 2022.

Introduction: Soft rot (SRP) bacteria are globally dispersed pathogens that cause significant economic loss in potato and other crops. Our understanding of the SRP species diversity has expanded in recent years due to advances and adoption of whole-genome sequence technologies. There are currently 34 recognized SRP species that belong to the and genera.

Reproducible Quantitative Trait Loci for Resistance to Soft Rot Caused by Derived from the Wild Potato (PI 458355) Are Located on Chromosomes 1, 3, and 5.

The potato wild relative is a breeder-friendly source of genetic resistance to soft rot. Our objectives were to (i) identify loci associated with soft rot resistance in germplasm and (ii) develop bi-parental populations in a self-compatible genetic background to recover segregating F progenies, construct a linkage map, and identify quantitative trait loci (QTLs). Under objective (i), tubers from 103 genotypes from the United States Potato Genebank were inoculated with a high virulence strain of , and lesion size was measured after a 24-h incubation period at 30°C.

First Report of Cucurbit Yellow Vine Disease Caused by on Cucurbits in New York.

Cucurbits are one of the most significant commodities in New York, with a value of $92.3 million in 2021 (NASS-USDA 2021). In August 2021, several acorn squash (Cucurbita pepo) cultivar Turbinate plants at Cornell AgriTech research farm in Geneva, NY, had chlorotic, wilting leaves, and older leaves appeared scorched.

First Report of Causing Bacterial Blackleg and Soft Rot of Potato in Pennsylvania.

Potato () plants showing blackleg and soft rot symptoms were collected at a commercial vegetable farm near Newmanstown, PA in August 2021 (Fig. S1). The incidence of potato blackleg in the unirrigated field was about 5 to 8%, but approximately 30% in the irrigated field.

Complete Genome Sequence Resource for a Recently Isolated Potato Ring Rot Pathogen, K496.

Potato ring rot caused by has been a devastating disease in the U.S. since 1930.

First Report of Rhizopus arrhizus (syn. R. oryzae) Causing Garlic Bulb Soft Rot in Hebei Province, China.

Rhizopus soft rot occurs on the succulent tissues of vegetables, fruits, and ornamental plants throughout the world (Cui et al. 2019). When the garlic is in the seedling stage in the fields (Fig.

Identification of Causing Blackleg of Potato in New York State.

Soft rot bacteria classified in the Pectobacteriaceae (SRP), including and spp., are responsible for soft rot and blackleg diseases of potato. Since 2014, blackleg outbreaks caused by have increased in the United States and Canada.

AlgU, a Conserved Sigma Factor Regulating Abiotic Stress Tolerance and Promoting Virulence in .

can rapidly deploy specialized functions to deal with abiotic and biotic stresses. Host niches pose specific sets of environmental challenges driven, in part, by immune defenses. Bacteria use a "just-in-time" strategy of gene regulation, meaning that they only produce the functions necessary for survival as needed.

Complete Genome Sequence of a Gram-Positive Bacterium, sp. Strain PS1209, a Potato Endophyte.

We report the complete and annotated genome sequence of a Gram-positive bacterium, sp. strain PS1209, a potato endophyte that was isolated from apparently healthy tubers of potato cultivar NY166. The circular genome is 4,091,164 bp long, with a GC content of 69.

Pseudomonas syringae AlgU Downregulates Flagellin Gene Expression, Helping Evade Plant Immunity.

Flagella power bacterial movement through liquids and over surfaces to access or avoid certain environmental conditions, ultimately increasing a cell's probability of survival and reproduction. In some cases, flagella and chemotaxis are key virulence factors enabling pathogens to gain entry and attach to suitable host tissues. However, flagella are not always beneficial; both plant and animal immune systems have evolved receptors to sense the proteins that make up flagellar filaments as signatures of bacterial infection.

Complete Genome Sequence of Dickeya dianthicola ME23, a Pathogen Causing Blackleg and Soft Rot Diseases of Potato.

In 2014, an outbreak of potato blackleg and soft rot disease emerged in North America and continues to impact potato production. Here, we report the annotated genome sequence of Dickeya dianthicola ME23, a strain hypothesized to be representative of the bacterial population responsible for this disease outbreak.

Pectobacterium and Dickeya Responsible for Potato Blackleg Disease in New York State in 2016.

Beginning in 2014, outbreaks of blackleg disease compromised potato (Solanum tuberosum) production in the northeastern United States. Disease severity was atypical for plantings with certified seed. During 2016, 43 samples with blackleg symptoms were analyzed, originating from more than 20 farms operating in New York State.

An AlgU-Regulated Antisense Transcript Encoded within the Pseudomonas syringae Gene Has a Positive Effect on Motility.

Production of bacterial flagella is controlled by a multitiered regulatory system that coordinates the expression of 40 to 50 subunits and ordered assembly of these elaborate structures. Flagellar expression is environmentally controlled, presumably to optimize the benefits and liabilities of having these organelles on cell growth and survival. We recently reported a global survey of AlgU-dependent regulation and binding in pv.

The ECF sigma factor, PSPTO_1043, in Pseudomonas syringae pv. tomato DC3000 is induced by oxidative stress and regulates genes involved in oxidative stress response.

The bacterial plant pathogen Pseudomonas syringae adapts to changes in the environment by modifying its gene expression profile. In many cases, the response is mediated by the activation of extracytoplasmic function (ECF) sigma factors that direct RNA polymerase to transcribe specific sets of genes. In this study we focus on PSPTO_1043, one of ten ECF sigma factors in P.

Population-genomic insights into emergence, crop adaptation and dissemination of pathogens.

Many bacterial pathogens are well characterized but, in some cases, little is known about the populations from which they emerged. This limits understanding of the molecular mechanisms underlying disease. The crop pathogen has been widely isolated from the environment, including wild plants and components of the water cycle, and causes disease in several economically important crops.

Comparative genomics of pathovar reveals novel chemotaxis pathways associated with motility and plant pathogenicity.

The majority of bacterial foliar plant pathogens must invade the apoplast of host plants through points of ingress, such as stomata or wounds, to replicate to high population density and cause disease. How pathogens navigate plant surfaces to locate invasion sites remains poorly understood. Many bacteria use chemical-directed regulation of flagellar rotation, a process known as chemotaxis, to move towards favorable environmental conditions.

AlgU Controls Expression of Virulence Genes in Pseudomonas syringae pv. tomato DC3000.

Unlabelled: Plant-pathogenic bacteria are able to integrate information about their environment and adjust gene expression to provide adaptive functions. AlgU, an extracytoplasmic function (ECF) sigma factor encoded by Pseudomonas syringae, controls expression of genes for alginate biosynthesis and genes involved with resisting osmotic and oxidative stress. AlgU is active while these bacteria are associated with plants, where its presence supports bacterial growth and disease symptoms.

Pseudomonas syringae pv. tomato DC3000 Type III Secretion Effector Polymutants Reveal an Interplay between HopAD1 and AvrPtoB.

The bacterial pathogen Pseudomonas syringae pv. tomato DC3000 suppresses the two-tiered plant innate immune system by injecting a complex repertoire of type III secretion effector (T3E) proteins. Beyond redundancy and interplay, individual T3Es may interact with multiple immunity-associated proteins, rendering their analysis challenging.

Global analysis of the HrpL regulon in the plant pathogen Pseudomonas syringae pv. tomato DC3000 reveals new regulon members with diverse functions.

The type III secretion system (T3SS) is required for virulence in the gram-negative plant pathogen Pseudomonas syringae pv. tomato DC3000. The alternative sigma factor HrpL directly regulates expression of T3SS genes via a promoter sequence, often designated as the "hrp promoter.

RecTE(Psy)-mediated recombineering in Pseudomonas syringae.

A recently developed Pseudomonas syringae recombineering system simplifies the procedure for installing specific mutations at a chosen genomic locus. The procedure involves transforming P. syringae cells expressing recombineering functions with a PCR product that contains desired changes flanked by sequences homologous to a target location.

Genomic plasticity enables phenotypic variation of Pseudomonas syringae pv. tomato DC3000.

Whole genome sequencing revealed the presence of a genomic anomaly in the region of 4.7 to 4.9 Mb of the Pseudomonas syringae pv.

Oligonucleotide recombination enabled site-specific mutagenesis in bacteria.

Recombineering refers to a strategy for engineering DNA sequences using a specialized mode of homologous recombination. This technology can be used for rapidly constructing precise changes in bacterial genome sequences in vivo. Oligonucleotide recombination is one type of recombineering that uses ssDNA oligonucleotides to direct chromosomal mutations.

Substrate and target sequence length influence RecTE(Psy) recombineering efficiency in Pseudomonas syringae.

We are developing a new recombineering system to assist experimental manipulation of the Pseudomonas syringae genome. P. syringae is a globally dispersed plant pathogen and an important model species used to study the molecular biology of bacteria-plant interactions.