Influence of Bacterial Competitors on and Enterohemorrhagic Growth in Microbiological Media and Attachment to Vegetable Seeds.

Interests in using biological agents for control of human pathogens on vegetable seeds are rising. This study evaluated whether probiotic bacterium GG, bacterial strains previously used as biocontrol agents in plant science, as well as a selected plant pathogen could compete with foodborne human pathogens, such as and enterohemorrhagic (EHEC), for growth in microbiological media and attachment to vegetable seeds; and to determine whether the metabolites in cell-free supernatants of competitive bacterial spent cultures could inhibit the growth of the two pathogens. The results suggest that the co-presence of competitive bacteria, especially GG, significantly ( < 0.

Evaluation of suitable reference genes for normalization of quantitative reverse transcription PCR analyses in Clavibacter michiganensis.

Clavibacter michiganensis, the causal agent of bacterial canker of tomato, is a Gram-positive bacterium and a model for studying plant diseases. The real-time quantitative reverse transcription PCR (real-time qRT-PCR) assay is widely used to quantify gene expression in plant pathogenic bacteria. However, accurate quantification of gene expression requires stably expressed reference genes that are consistently expressed during the experimental conditions of interest.

Induction and Resuscitation of the Viable but Non-culturable (VBNC) State in , the Causal Agent of Bacterial Fruit Blotch of Cucurbitaceous Crops.

is a gram-negative bacterium that infects a wide range of cucurbits causing bacterial fruit blotch (BFB) disease. Copper-based compounds are the most widely-used chemicals for managing BFB and other bacterial diseases in the field. Many bacteria can enter a viable but non-culturable (VBNC) state in response to stress, including exposure to copper, and recover the culturability when favorable conditions return.

Fate of Salmonella enterica and Enterohemorrhagic Escherichia coli Cells Artificially Internalized into Vegetable Seeds during Germination.

Vegetable seeds contaminated with bacterial pathogens have been linked to fresh-produce-associated outbreaks of gastrointestinal infections. This study was undertaken to observe the physiological behavior of and enterohemorrhagic (EHEC) cells artificially internalized into vegetable seeds during the germination process. Surface-decontaminated seeds of alfalfa, fenugreek, lettuce, and tomato were vacuum-infiltrated with four individual strains of or EHEC.

Differential Attachment of Salmonella enterica and Enterohemorrhagic Escherichia coli to Alfalfa, Fenugreek, Lettuce, and Tomato Seeds.

Vegetable seeds have the potential to disseminate and transmit foodborne bacterial pathogens. This study was undertaken to assess the abilities of selected and enterohemorrhagic (EHEC) strains to attach to fungicide-treated versus untreated, and intact versus mechanically damaged, seeds of alfalfa, fenugreek, lettuce, and tomato. Surface-sanitized seeds (2 g) were exposed to four individual strains of or EHEC at 20°C for 5 h.

Embryo Localization Enhances the Survival of Acidovorax citrulli in Watermelon Seeds.

Acidovorax citrulli, the causal agent of bacterial fruit blotch (BFB) of cucurbits has been observed to survive for >34 years in stored melon and watermelon seeds. To better understand this remarkable longevity, we investigated the bacterium's tolerance to desiccation and the effect of bacterial localization in different watermelon seed tissues on its survival. We compared the ability of A.

The type VI protein secretion system contributes to biofilm formation and seed-to-seedling transmission of Acidovorax citrulli on melon.

The type VI protein secretion system (T6SS) is essential for the virulence of several Gram-negative bacteria. In this study, we identified a T6SS gene cluster in Acidovorax citrulli, a plant-pathogenic bacterium that causes bacterial fruit blotch (BFB) of cucurbits. One T6SS cluster, of approximately 25 kb in length and comprising 17 genes, was found in the A.

Development of an improved isolation approach and simple sequence repeat markers to characterize Phytophthora capsici populations in irrigation ponds in southern Georgia.

Phytophthora capsici, the causal agent of Phytophthora blight, is a major concern in vegetable production in Georgia and many other states in the United States. Contamination of irrigation water sources by P. capsici may be an important source of inoculum for the pathogen.

The epidemiology and management of seedborne bacterial diseases.

Although seed production has been moved to semiarid regions to escape seedborne pathogens, seedborne bacterial diseases continue to be problematic and cause significant economic losses worldwide. Infested seeds are responsible for the re-emergence of diseases of the past, movement of pathogens across international borders, or the introduction of diseases into new areas. Considerable attention has been paid to improving the sensitivity and selectivity of seed health assays by using techniques such as flow cytometry and the polymerase chain reaction.