Characterization of strains from pepper and tomato.

Disease outbreaks of bacterial leaf spot and blight of pepper and tomato often occur in both transplant- and field-production systems worldwide. In some cases, the outbreaks are caused by novel bacterial species. Characterization of these novel bacterial species are critical in developing diagnostic assays and identifying management options for pathogen monitoring and sustainable production, respectively.

Genome-wide association and dissociation studies in reveal potential virulence factors affecting and × hybrid.

is a member of a species complex that causes center rot of bulb onions () and also infects other crops like leeks (), chives (), bunching onion or Welsh onion (), and garlic (). This pathogen relies on a chromosomal phosphonate biosynthetic gene cluster (HiVir) and a plasmid-borne thiosulfinate tolerance cluster () for onion pathogenicity and virulence, respectively. However, pathogenicity and virulence factors associated with other species remain unknown.

Evaluating Options to Increase the Efficacy of Biocontrol Agents for the Management of spp. Under Field Conditions.

Center rot of onion is caused by a complex of plant pathogenic species, which can lead to significant yield losses in the field and during storage. Conventional growers use foliar protectants such as a mixture of copper bactericides and an ethylene-bis-dithiocarbamate (EBDC) fungicide to manage the disease; however, organic growers have limited management options besides copper-protectants. Biocontrol agents (BCAs) provide an alternative; however, their efficacy could be compromised due in part to their inability to colonize the foliage.

A Novel Biosynthetic Gene Cluster Across the Species Complex Is Important for Pathogenicity in Onion.

Onion center rot is caused by at least four species of genus (, , , and subsp). Critical onion pathogenicity determinants for were recently described, but whether those determinants are common among other onion-pathogenic species remains unknown. In this work, we report onion pathogenicity determinants in subsp and We identified two distinct secondary metabolite biosynthetic gene clusters present separately in different strains of onion-pathogenic subsp.

, a new bacterial pathogen of onion causing bulb rot.

Onion bulb rot can be caused by multiple plant pathogens including bacterial pathogens. During our routine survey of commercial onion farms in 2014, 2020, and 2021, seven putative spp. strains were isolated from symptomatic onion samples in Georgia, United States.

Micronutrients Affect Expression of Induced Resistance Genes in Hydroponically Grown Watermelon against Fusarium oxysporum f. sp. niveum and Meloidogyne incognita.

The soil-borne pathogens, particularly f. sp. (FON) and southern root-knot nematode (RKN, ) are the major threats to watermelon production in the southeastern United States.

Pseudomonas alliivorans sp. nov., a plant-pathogenic bacterium isolated from onion foliage in Georgia, USA.

This study provides a taxonomic characterization of three bacterial strains isolated from onion seedlings in Georgia USA. Yellow-colored colonies were isolated, and a diffusible fluorescent pigment was visible under ultraviolet light on King's medium B. Preliminary analysis of the basic phenotype tests and 16S rRNA gene sequence analysis indicated the onion strains were closely related to Pseudomonas viridiflava with the highest similarity to P.

Pan-Genome-Wide Analysis of Identified Genes Linked to Pathogenicity in Onion.

Pantoea ananatis, a gram negative and facultative anaerobic bacterium is a member of a spp. complex that causes center rot of onion, which significantly affects onion yield and quality. This pathogen does not have typical virulence factors like type II or type III secretion systems but appears to require a biosynthetic gene-cluster, HiVir/PASVIL (located chromosomally comprised of 14 genes), for a phosphonate secondary metabolite, and the '' gene cluster (located in plasmid and comprised of 11 genes) that aids in bacterial colonization in onion bulbs by imparting tolerance to thiosulfinates.

Pan-Genome of Novel subsp. Reveals Genes Involved in Onion Pathogenicity and Evidence of Lateral Gene Transfer.

subsp. () is a causative agent of leafspot on foxtail millet and pearl millet; however, novel strains were recently identified that are pathogenic on onions. Our recent host range evaluation study identified two pathovars; subsp.

sp. nov., a plant-pathogenic bacterium isolated from pepper leaf in Georgia, USA.

Three phytopathogenic bacterial strains (Pc19-1, Pc19-2 and Pc19-3) were isolated from seedlings displaying water-soaked, dark brown-to-black, necrotic lesions on pepper () leaves in Georgia, USA. Upon isolation on King's medium B, light cream-coloured colonies were observed and a diffusible fluorescent pigment was visible under ultraviolet light. Analysis of their 16S rRNA gene sequences showed that they belonged to the genus , with the highest similarity to ATCC 10857 (99.

, a new species causing leaf dieback disease of pecan ().

species are endophytes and pathogens of woody hosts and members of the Botryosphaeriaceae. Leaf dieback is a new disease resulting in death of compound leaves and extensive defoliation of pecan trees () throughout the southeastern United States. Currently, the disease is consistently most severe on trees that are not managed with fungicides for pecan scab.

Identification of Two Novel Pathovars of subsp. Affecting sp. and Millets.

subsp. is a causative agent of leafspot of foxtail millet and pearl millet; however, novel strains were recently identified that are pathogenic on onion. We phenotypically and genotypically characterized 17 .

Foliar Chemical Protection Against in Onion Is Negated by Thrips Feeding.

Center rot of onion, caused by , is an economically important disease in onion production in Georgia and elsewhere in the United States. Growers rely on frequent foliar applications of bactericides and, in some cases, plant defense inducers to manage this disease. However, regular prophylactic application of these chemicals is not cost-effective and may not be environmentally friendly.

Pathogenicity and a TaqMan Real-Time PCR for Specific Detection of , a Bacterial Pathogen of Onions.

Bacterial diseases of onion are reported to cause significant economic losses. Brady, one of the pathogens causing the center rot on onions, has not yet been reported in Canada. We report the pathogenicity of on commercially available Canadian green onions (scallions).

Isolation and Characterization of Novel Pantoea stewartii subsp. indologenes Strains Exhibiting Center Rot in Onion.

Center rot of onion is an economically important disease caused by three Pantoea spp.: Pantoea ananatis, P. agglomerans, and P.

Pseudomonas coronafaciens sp. nov., a new phytobacterial species diverse from Pseudomonas syringae.

We propose Pseudomonas coronafaciens sp. nov. as a new species in genus Pseudomonas, which is diverse from P.

Genetic Diversity Analysis Reveals Limited Genomic Diversity as Well as Accessory Genes Correlated with Onion Pathogenicity.

is a member of the family Enterobacteriaceae and an enigmatic plant pathogen with a broad host range. Although strains can be aggressive on onion causing foliar necrosis and onion center rot, previous genomic analysis has shown that lacks the primary virulence secretion systems associated with other plant pathogens. We assessed a collection of fifty strains collected from Georgia over three decades to determine genetic factors that correlated with onion pathogenic potential.

Interaction of Onion Cultivar and Growth Stages on Incidence of Pantoea ananatis Bulb Infection.

Center rot, caused by Pantoea ananatis, has been one of the most important bacterial diseases of onion leading to considerable economic losses. Symptoms can be expressed in the onion foliage and bulb, with the pathogen moving from the infected leaves to bulb scales. However, little is known regarding which growth stage the plant is most susceptible to bulb infection and if there are differences in susceptibility to bulb infection among sweet onion cultivars.

A Risk Assessment Model for Bacterial Leaf Spot of Pepper (Capsicum annuum), Caused by Xanthomonas euvesicatoria, Based on Concentrations of Macronutrients, Micronutrients, and Micronutrient Ratios.

The phytopathogenic bacterium Xanthomonas euvesicatoria causes bacterial leaf spot (BLS) of pepper and has a worldwide distribution. BLS is difficult to control and an integrated management strategy that incorporates crop rotation, use of clean seed and clean plants, weed control, resistant varieties, applications of bactericides, biocontrol agents, and systemic acquired resistance (SAR) inducers is generally recommended. However, even with that arsenal of weapons, BLS can still be responsible for severe losses under favorable environmental conditions.

Epiphytic Survival of Pantoea ananatis on Richardia scabra L. in Georgia.

Pantoea ananatis, the causal organism of center rot of onion (Allium cepa L.), can survive on different weeds but, in a previous survey, it was most commonly found on Florida pusley (Richardia scabra L.).

Interactions Between Frankliniella fusca and Pantoea ananatis in the Center Rot Epidemic of Onion (Allium cepa).

An Enterobacteriaceae bacterium, Pantoea ananatis (Serrano) Mergaert, is the causal agent of an economically important disease of onion, center rot. P. ananatis is transmitted by an onion-infesting thrips, Frankliniella fusca (Hinds).

Thrips Settling, Oviposition and IYSV Distribution on Onion Foliage.

Thrips tabaci Lindeman (Thysanoptera: Thripidae) adult and larval settling and oviposition on onion (Allium cepa L.) foliage were investigated in relation to leaf position and leaf length at prebulb plant growth stages under controlled conditions. In the laboratory, four and six adult females of T.

First Report of Bacterial Blight of Sugar Beet Caused by Pseudomonas syringae pv. aptata in Georgia, USA.

Sugar beet (Beta vulgaris L.) is not currently a commercial crop in Georgia, but experimental plantings as a winter rotational crop are promising in terms of yield and industrial sugar production (T. Brenneman, personal communication).

Interactions of seedborne bacterial pathogens with host and non-host plants in relation to seed infestation and seedling transmission.

The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv.

Distribution and Survival of Pseudomonas sp. on Italian Ryegrass and Curly Dock in Georgia.

Yellow bud, caused by Pseudomonas sp., is an emerging bacterial disease of onion. A polymerase chain reaction assay based on the coronafacate ligase (cfl) and HrpZ genes was used to detect initial suspected bacteria on weeds.