Progress 10/01/15 to 09/30/19
Outputs
Target Audience:Results from this research were reported at Food Research Institute Annual Meeting, University of Wisconsin - Madison to an audience of researchers and food company representatives and to scientists at the Entomological Society of America's annual meeting. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Dr. Barak have directly mentored the graduate student, Victoria Lason, who has carried out all the experiments described, along with the undergraduate researcher, Matt Maurice. How have the results been disseminated to communities of interest?We reported our results at public seminars at the University of Wisconsin - Madison, Food Research Institute which was attended by researchers and food producers interested in food safety, scientists at entomological society and molecular plant - microbe interactions meetings and the Korean Rural Development Administration. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
The overall goal of this project has provided fundamental knowledge of how phytophagous Hempiterans increase the survival and persistence of human bacterial pathogens, such as Salmonella enterica, on raw, fresh produce that results in a higher risk of human illness. We investigated each component of the tri-trohpic interaction: insect, bacterial pathogen, and plant host. We designed a system to measure electrolyte leakage caused by leafhopper feeding. This was time- and host-dependent. In the first 24 h following leafhopper infestation, tomato plants have extensive electrolyte leakage, which tapers off, and the host compensates for insect feeding thereafter. Lettuce plants experience consistent cellular damage throughout leafhopper infestation. We found that cellular damage was correlated with an increase in Salmonella. Both Salmonella Pathogenicity Island (SPI)-1 and SPI-2 play critical roles in the persistence and infection of S. enterica within animals. Previously, we showed that eliminating the SPI-1 type 3 (T3) secretion system and translocation of T3 effectors disrupted S. enterica persistence in the leafhopper gut. We created a library of SPI-1 and SPI-2 mutants of the structural needle, ATP synthase, and individual effectors. We screened these mutants for a role in S. enterica persistence in the leafhopper gut or transmission by the leafhopper from contaminated plants to adjacent plants. Individually, these mutants were not responsible for S. enterica survival in the leafhopper gut or other specific steps in the microbe - insect interaction. We investigated the role of host defense or changes in host defense due to leafhopper infestation and persistence of S. enterica on tomato plants. We monitored jasmonic acid and salicylic acid defense pathways. Both pathways are induced by insect infestation and the two pathways do not appear to be in contrast with each other as previously reported. Induction of the jasmonic acid defense pathway directly influences Salmonella survival; as the defense pathway is induced, S. enterica populations over time. These results add to our knowledge of how phytophagous insect infestation leads to Salmonella persistence on lettuce and tomato. The risk of leafhopper infestation resulting in foodborne illness from consumption of raw produce can be more clearly described. Initial leafhopper infestation to a tomato crop may increase lead to a small increase in Salmonella persistence for a short period. However, leafhopper infestation in lettuce may lead to a persistent increase in Salmonella populations if the pest remains in the crop. In cropping systems with few control measures for leafhoppers, infestation events may be significant food safety risks.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Lason, V., Groves, R., Barak, J. Intracellular penetration by Macrosteles quadrilineatus enhances Salmonella enterica persistence in the phyllosphere. Entomological Society of America, St. Louis, Missouri, November 17 20
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Maurice, M., Lason, V., Barak, J., Groves, R. Cellular damage caused by Frankliniella occidentalis feeding increases Salmonella enterica persistence on tomato plants. Food Research Institute Annual Meeting, University of WI-Madison, May 23-24
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2019
Citation:
Lason, V., Maurice, M., Barak, J., Groves, R. How do leafhoppers enhance Salmonella enterica populations in the phyllosphere? Food Research Institute Annual Meeting, University of WI-Madison, May 23 - 24
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Progress 10/01/17 to 09/30/18
Outputs
Target Audience:Results from this research were reported at Food Research Institute Annual Meeting, University of Wisconsin - Madison to an audience of researchers and food company representatives. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Dr. Barak hasdirectly mentored the graduate student, Victoria Lason, who has carried out all the experiments described, along with the undergraduate researcher, Matt Maurice. How have the results been disseminated to communities of interest?We have reported our results at public seminars at the University of Wisconsin - Madison, Food Research Institute attended by researchers and food producers interested in food safety. What do you plan to do during the next reporting period to accomplish the goals?We plan to continue our investigation of insect factors that influence Salmonella survival and dispersal in and among plants, how plant defense changes due to insect feeding, and mechanisms used by Salmonella to survive internalization and passage through the alimentary canal of phytophagous hemipterans.
Impacts
What was accomplished under these goals?
For objective 1, we investigated the role of thrips in Salmonella growth and persistence on tomato. We conducted both open and closed arena experiments. We analyzed how infestation densities and plant age influence cellular damage and Salmonella persistence. While over time more feeding lesions occur, plant age and infestation densities were not significant drivers of Salmonella survival on tomato leaves. For objective 2, we monitored jasmonic acid and salicylic acid defense pathway induction from Salmonella contamination and insect infestation. Both pathways are induced by insect infestation and the two pathways do not appear to be in contrast to each other as previously reported. Induction of the jasmonic acid defense pathway directly influences Salmonella survival by increasing populations over time. These results add to our knowledge of how phytophagous insect infestation leads to Salmonella persistence on lettuce and tomato.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Victoria Lason, Russell L Groves, and Jeri D. Barak. Connecting insects and human enteric bacterial pathogens: using electrical conductivity as a proxy for direct plant damage caused by Macrosteles quadrilineatus in lettuce and tomato. 2018 Entomology Society of America, North Central Branch Meeting, August 7-11, Madison, WI.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Victoria Lason, Matthew Maurice, Russell L Groves, and Jeri D. Barak. Areas of macroscopic damage caused by western flower thrips (Frankliniella occidentalis) exhibit greater cellular damage and promote Salmonella enterica populations. 2018 Entomology Society of America Annual Meeting, November 11-14, Vancouver, BC, Canada.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Victoria Lason, Matthew Maurice, Russell L Groves, and Jeri D. Barak. Analyzing how insect mechanisms and plant architecture influence Salmonella enterica populations. 2018 Food Research Institute Annual Meeting, May 23-24, Madison.
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Progress 10/01/16 to 09/30/17
Outputs
Target Audience:We have reported our results at public seminars at the University of Wisconsin - Madison, Food Research Institute attended by researchers and food producers interested in food safety and to the USDA-ARS-NADC research community. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Dr. Barak directly mentored the graduate student, Ryan Bower, who carried out all the experiments described, along with the undergraduate researcher, June Pen. How have the results been disseminated to communities of interest?We reported our results at public seminars at the University of Wisconsin - Madison, Food Research Institute, which was attended by researchers and food producers interested in food safety and to the USDA-ARS-NADC research community. What do you plan to do during the next reporting period to accomplish the goals?We plan to continue our investigation of insect factors that influence Salmonella survival and dispersal in and among plants, how plant defense changes due to insect feeding, and mechanisms used by Salmonella to survive internalization and passage through the alimentary canal of phytophagous hemipterans.
Impacts
What was accomplished under these goals?
For objective 1, we are identifying leafhopper feeding patterns on tomato and lettuce leaves. We found that experimental design strongly influences the results. We measured electrolyte leakage and found that leafhopper infestation resulted in an increase. This was time dependent between host plants, leakage was consistent over time when leafhoppers fed on lettuce but only detectable on tomato leaves 24 h post-infestation. For objective 2, we monitored jasmonic acid and salicylic acid defense pathway induction from Salmonella contamination and insect infestation. Both pathways are induced by insect infestation and the two pathways do not appear to be in contrast to each other as previously reported. For objective 3, we investigated the role of biofilm factors for their role in Salmonella persistence in the insect gut. We found that overproduction of biofilm factors regulated by CsgD led to an increase in persistence within the gut. These results add to our knowledge of how phytophagous insect infestation leads to Salmonella persistence on lettuce and tomato.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Strangers with benefits, remaking the phyllosphere through disease, Special Session, Phyllosphere Microbial Assemblages: Friends, Foes, and Strangers, American Phytopathological Society Annual Meeting, San Antonio, TX, August 5-9.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
A m�nage � trois that benefits Salmonella enterica. National Animal Disease Center, USDA ARS, Ames, IA. Sept. 19, 2017
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Progress 10/01/15 to 09/30/16
Outputs
Target Audience:Results from this research were reported at the Food Research Institute annual meeting and Korean Society of Food Hygiene and Safety in Seoul, Korea to an audience of researchers and food company representatives. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Dr. Barak directly mentored the graduate student, Ryan Bower, who carried out all the experiments described, along with the undergraduate researcher, June Pen. How have the results been disseminated to communities of interest?We reported our results at public seminars at the University of Wisconsin - Madison, Food Research Institute attended by researchers and food producers interested in food safety, to the international community at the Korean Society of Food Hygiene and Safety. What do you plan to do during the next reporting period to accomplish the goals?We plan to continue our investigation of insect factors that influence Salmonella survival and dispersal in and among plants, how plant defense changes due to insect feeding, and mechanisms used by Salmonella to survive internalization and passage through the alimentary canal of phytophagous hemipterans.
Impacts
What was accomplished under these goals?
For objective 2, we have identified the key plant defense genes in tomato and validated qRT-PCR primers which will track induction of jasmonic acid and salicylic acid defense pathways. The initial aim of objective 3 is to determine critical elements encoded on Salmonella's Salmonella Pathogenicity Island (SPI)-1 and/or SPI-2 type 3 (T3) needle complex which are required for bacterial persistence within ALHs. The rationale for this objective is based upon prior knowledge that both SPI-1 and SPI-2 play critical roles in the persistence and infection of S. enterica within animals. We have generated homologous components of the SPI-1 and SPI-2 T3 mutants of the structural needle, ATP synthase, and effectors.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Produce not where and what you expected, Food Research Institute Annual Meeting, University of Wisconsin Madison, April 18-19.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Phytophagous Hemipterans as risk factors for leafy green contamination by Salmonella, Korean Society of Food Hygiene and Safety, Seoul, Korea, October 17
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