A foliar disease of invasive black swallow-wort () caused by .

Black swallow-wort () is an aggressive invasive vine infesting pastures and fields in the northeastern United States. An unknown fungal pathogen was recovered from foliar lesions occurring on black swallow-wort at two locations in Rhode Island in 2022 and was identified as based on morphological and molecular descriptions of eight isolates. The potential weed biological control value of a single isolate, FDWSRU 22-216, was evaluated through colonized agar block and conidial spray inoculations of black swallow-wort.

Phytopathogenic bacterial survival on artificial substrates.

The ability of phytopathogenic bacteria to survive desiccation on inanimate substrates has important implications for managing potential contamination and resulting bacterial spread during both real-world horticultural operations and laboratory experimentation. Here we demonstrate that and are all capable of surviving desiccation on both polystyrene plastic and glass surfaces and that the likelihood of survival increases with increasing initial bacterial concentration. was recovered at higher frequencies from plastic than from glass, while the other species were recovered at roughly equal frequencies from each surface.

Emergence of a novel Alternaria species infecting invasive garlic mustard () in the United States.

The Brassicaceae invasive weed, garlic mustard (Alliaria petiolata), is a Eurasian biennial herb that has rapidly spread across North America infesting forests and field borders, negatively impacting plant biodiversity and agroecosystem health. In 2022, a severe garlic mustard dieback event occurred in a limited section of a large, forested garlic mustard population in Maryland, United States. Diseased plants were heavily defoliated with remaining intact leaves having irregular-shaped necrotic and chlorotic lesions.

Characterization of Emerging Isolates on the Nonnative Weed Garlic Mustard ().

Nonnative plant infestations provide unique opportunities to investigate pathogen emergence with evolutionarily recent plant introduction events. The widespread distribution of invasive plants and their proximity to genetically related crops highlights the risks of nonnative plants acting as ancillary hosts and fostering microbial recombination and pathogen selection. Garlic mustard () is a widespread, nonnative cruciferous weed that grows throughout North America and along the forested edges of diverse agricultural fields.

Cruciferous Weed Isolates of Yield Insight into Pathovar Genomic Relationships and Genetic Determinants of Host and Tissue Specificity.

Pathovars of cause distinct diseases on different brassicaceous hosts. The genomic relationships among pathovars as well as the genetic determinants of host range and tissue specificity remain poorly understood despite decades of research. Here, leveraging advances in multiplexed long-read technology, we fully sequenced the genomes of a collection of strains isolated from cruciferous crops and weeds in New York and California as well as strains from global collections, to investigate pathovar relationships and candidate genes for host- and tissue-specificity.

Genome Sequence of Xanthomonas campestris Strain FDWSRU 18048, an Emerging Pathogen of Nonnative, Invasive Garlic Mustard ().

Xanthomonas campestris infections of nonnative, invasive garlic mustard populations have been recently reported in the eastern United States. Here, we report the genome sequence of the pathogenic X. campestris strain FDWSRU 18048.

Cruciferous Weeds Do Not Act as Major Reservoirs of Inoculum for Black Rot Outbreaks in New York State.

Cruciferous weeds have been shown to harbor diverse pathovars, including the agronomically damaging black rot of cabbage pathogen, pv. However, the importance of weeds as inoculum sources for pv. outbreaks in New York remains unknown.

Comparative Secretome Analyses of Toxigenic and Atoxigenic Species.

Phytopathogenic species are unique bacterial plant pathogens because they are obligately vectored by plant parasitic anguinid nematodes to the developing seedheads of forage grasses and cereals. This understudied group of plant-associated Actinomycetes includes the neurotoxigenic plant pathogen , which causes annual ryegrass toxicity in grazing livestock. is currently endemic to Australia and is listed as a plant pathogen select agent by the U.

Bacterial Canker of Tomato: Revisiting a Global and Economically Damaging Seedborne Pathogen.

The gram-positive actinobacterium is the causal agent of bacterial canker of tomato, an economically impactful disease with a worldwide distribution. This seedborne pathogen systemically colonizes tomato xylem leading to unilateral leaflet wilt, marginal leaf necrosis, stem and petiole cankers, and plant death. Additionally, splash dispersal of the bacterium onto fruit exteriors causes bird's-eye lesions, which are characterized as necrotic centers surrounded by white halos.

, sp. nov., a newly described rust on the federally endangered plant, California sea-blite ().

Rust disease was observed on populations of near Morro Bay, California. The pathogen was identified as a species of based on teliospore and urediniospore morphology and nuc 28S rDNA sequence analysis. The isolate was compared with previously described species of that infect members of Chenopodiaceae, prompting a taxonomic reevaluation of species on .

Comparative Evaluation of LAMP, qPCR, Conventional PCR, and ELISA to Detect in Kenyan Potato Fields.

Bacterial wilt caused by is considered among the most damaging diseases of potato in Sub-Saharan Africa and the most significant biotic constraint of potato production alongside late blight. Unlike late blight, which can be managed by chemical means, can only be managed through cultural methods and clean seed. Laboratory testing to certify seed before planting is required to confirm the absence of the pathogen in Kenya.

Partial Proteome of the Corynetoxin-Producing Gram-Positive Bacterium, Rathayibacter toxicus.

Rathayibacter toxicus is a Gram-positive bacterium that is the causative agent of annual ryegrass toxicity (ARGT), a disease that causes devastating losses in the Australian livestock industry. R. toxicus exhibits a complex life cycle, using the nematode Anguina funesta as a physical vector to carry it up to the seed head of the host plant.

Plant-like bacterial expansins play contrasting roles in two tomato vascular pathogens.

Expansin proteins, which loosen plant cell walls, play critical roles in normal plant growth and development. The horizontal acquisition of functional plant-like expansin genes in numerous xylem-colonizing phytopathogenic bacteria suggests that bacterial expansins may also contribute to virulence. To investigate the role of bacterial expansins in plant diseases, we mutated the non-chimeric expansin genes (CmEXLX2 and RsEXLX) of two xylem-inhabiting bacterial pathogens, the Actinobacterium Clavibacter michiganensis ssp.

Whole genome sequence of two Rathayibacter toxicus strains reveals a tunicamycin biosynthetic cluster similar to Streptomyces chartreusis.

Rathayibacter toxicus is a forage grass associated Gram-positive bacterium of major concern to food safety and agriculture. This species is listed by USDA-APHIS as a plant pathogen select agent because it produces a tunicamycin-like toxin that is lethal to livestock and may be vectored by nematode species native to the U.S.

Characterizing the Genetic Diversity of the Clavibacter michiganensis subsp. michiganensis Population in New York.

New York Clavibacter michiganensis subsp. michiganensis isolates, collected from disparate bacterial canker of tomato outbreaks over the past 11 years, were characterized with a multilocus sequence analysis (MLSA) scheme that differentiated the 51 isolates into 21 haplotypes with a discriminatory power of 0.944.

Tomato fruit and seed colonization by Clavibacter michiganensis subsp. michiganensis through external and internal routes.

The Gram-positive bacterium Clavibacter michiganensis subsp. michiganensis, causal agent of bacterial wilt and canker of tomato, is an economically devastating pathogen that inflicts considerable damage throughout all major tomato-producing regions. Annual outbreaks continue to occur in New York, where C.