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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Foodborne Toxin Detection and Prevention Research » Research » Research Project #438564

Research Project: Novel Methods for the Mitigation of Human Pathogens and Mycotoxin Contamination of High Value California Specialty Crops

Location: Foodborne Toxin Detection and Prevention Research

2022 Annual Report


Accomplishments
1. A novel portable x-ray irradiator system for sterile insect technique. Sterile insect technique is a well-established insect suppression strategy. However, insects sterilized through irradiation in large facilities must be transported to the release site, often affecting insect fitness and overall effectiveness. On-site sterilization using traditional means is not practical. ARS researchers in Albany, California, have developed a novel x-ray based irradiation unit that can be transported on a small truck and operate in the field. This technology supports mobile on-site rearing and release programs for rapid response to newly discovered invasive species.

2. Developed a model of fungal intestinal infections in insects. For most studies where insects are exposed to microbial pathogens, the microbes are delivered in a model of a septic injury, using a needle previously dipped in a concentrated microbial solution. However, this model does not represent the physiological way the insects are exposed to microbes. Insects like flies and moths naturally accumulate microbes in their intestines after eating microbe-rich food, such as decaying fruits. Many insect pests of agricultural importance beneficially co-exist with fungal pathogens and participate in fungal transmission. ARS researchers in Albany, California, developed a new model of fungal intestinal infection of insects using two surrogate organisms: vinegar fly as a host and baker's yeast as a fungus. This model is useful for identifying new chemical inhibitors of insect and fungal pests and understanding interactions of insects with fungi on the molecular and genetic levels. The model is also useful for discovering chemical inhibitors of the navel orangeworm moth, which coexists with and contributes to the transmission of mycotoxins-producing Aspergillus fungi.

3. Natural salicylaldehyde for fungal and pre- and post-emergent weed control. The control of weeds in crop fields is an important task for the agricultural industry. Uncontrolled weed growth engenders diverse flora in crop fields, which not only compete with crops for water and nutrients but are also harmful pests that damage and contaminate crops, especially fungicide-resistant fungi that produce mycotoxins. ARS researchers in Albany, California, developed a sustainable weed control strategy using salicylaldehyde (SA), a natural, generally recognized as safe food additive, as the active ingredient. Researchers showed that SA possesses both pre- and post-emergent herbicidal activity, and that the emitted SA completely prevented the germination of plant seeds and/or the growth of the germinated plants. SA also possesses an intrinsic antifungal activity that overcomes fungicide resistance of fungal pathogens. Tree nutshell particles were used as SA delivery vehicles for use in orchards, thus contributing to the growers’ sustainable by-product recycling program. Soil covering (i.e. soil pasteurization) was determined to be one of the optimum practices to effectively deliver SA to the soil.


Review Publications
Kim, J., Tam, C.C., Chan, K.L., Mahoney, N., Cheng, L.W., Friedman, M., Land, K.M. 2022. Antimicrobial efficacy of edible mushroom extracts: assessment of fungal resistance. Applied Sciences. 12(9). Article 4591. https://doi.org/10.3390/app12094591.
Kim, J., Cheng, L.W., Land, K.M., Gruhlke, M.C. 2021. Editorial: Redox-active molecules as antimicrobials: Mechanisms and resistance. In: Gruhlke, M.C.H., Kim, J.H., Land, K.M., Cheng, L., editors. Redox-Active Molecules as Antimicrobials: Mechanisms and Resistance. Lausanne, Switzerland: Frontiers Media SA. p. 4-6. https://doi.org/10.3389/978-2-88971-637-1.
Kim, J., Chan, K.L. 2022. Natural salicylaldehyde for fungal and pre- and post-emergent weed control. Applied Sciences. 12(8). Article 3749. https://doi.org/10.3390/app12083749.
Jenkins, D.M., Watanabe, S., Haff, R.P., Melzer, M.J., Jackson, E.S., Liang, P. 2021. Dose response of coconut rhinoceros beetle (Coleoptera: Scarabaeidae) to 92 kV x-ray irradiation. Journal of Applied Entomology. 145(10):1039-1049. https://doi.org/10.1111/jen.12930.
Kim, J., Tam, C.C., Chan, K.L., Cheng, L.W., Land, K.M., Friedman, M., Chang, P. 2021. Antifungal efficacy of redox-active natamycin against some foodborne fungi—comparison with Aspergillus fumigatus. Foods. 10(9). Article 2073. https://doi.org/10.3390/foods10092073.
Palumbo, J.D., O'Keeffe, T.L. 2021. Method for high-throughput antifungal activity screening of bacterial strain libraries. Journal of Microbiological Methods. 189. Article 106311. https://doi.org/10.1016/j.mimet.2021.106311.
Samaddar, S., Karp, D., Schmidt, R., Devarajan, J., McGarvey, J.A., Pires, A., Scow, K. 2021. Role of soil in the regulation of human and plant pathogens: Soils' contributions to people. Philosophical Transactions of the Royal Society B. 376. Article 20200179. https://doi.org/10.1098/rstb.2020.0179.
Tam, C.C., Nguyen, K., Nguyen, D., Hamada, S., Kwon, O., Kuang, I., Gong, S., Escobar, S., Liu, M., Kim, J., Hou, T., Tam, J., Cheng, L., Kim, J., Land, K.M., Friedman, M. 2021. Antimicrobial properties of tomato leaves, stems, and fruit and their relationship to chemical composition. BMC Complementary Medicine and Therapies. 21. Article 229. https://doi.org/10.1186/s12906-021-03391-2.
Tran, T., Hnasko, R.M., Huynh, S., Parker, C.T., Gorski, L.A., McGarvey, J.A. 2021. Complete genome sequence of Enterobacter asburiae strain AEB30, determined using Illumina and PacBio sequencing. Microbiology Resource Announcements. 10(31). Article e00562-21. https://doi.org/10.1128/MRA.00562-21.