Location: Food Quality Laboratory
2023 Annual Report
Objectives
Objective 1: Elucidate genes and mechanisms involved in postharvest pathology of fruits, such as apple (NP303, C2, PS 2b).
Sub-objective 1.A. Functionally analyze 14 specific single-copy genes in Penicillium expansum using recombinant DNA technologies and evaluate mutants for defects in fruit decay, virulence, and patulin production.
Sub-objective 1.B. Evaluate P. expansum mutants to inhibit and/or outcompete wild type Penicillium spp. in vitro and under controlled storage conditions.
Objective 2: Develop and optimize new treatments during storage to enhance postharvest decay management of fruits. (NP303, C3, PS 3b).
Sub-objective 2.A. Determine the spore holding capacity of wooden and plastic storage bins and the ability of bin inoculum to manifest in postharvest decay for stored fruit.
Sub-objective 2.B: Examine and optimize new treatments to reduce fungal inoculum, combat antimicrobial resistance, and prevent rot of pome fruit during storage.
Approach
This plan will develop innovative methods, tools, and approaches to manage blue mold. Systems-based analysis of omics data has revealed virulence gene candidates expressed by Penicillium expansum during apple fruit decay. The basic research outlined in Objective 1 will verify virulence gene function in P. expansum, create new mutant antagonists, generate new fundamental information, and fill existing knowledge gaps. The applied research contained in Objective 2 will determine optimal approaches for bin sanitation, develop novel methods to reduce fungal inoculum responsible for decay, and evaluate new antagonists to block decay. Fundamental information and antagonists generated in Objective 1, coupled with practical outcomes from Objective 2, will be integrated to deliver timely solutions that impact science, industry, and the public. Optimal postharvest decay management will enhance the viability, strengthen longevity, and increase the competitiveness of the US in the global fruit market and reduce food loss and waste at commercial and consumer levels.
Progress Report
Significant progress has been achieved on both objectives dealing with fundamental and translational aspects for solving blue mold decay as outlined in the base research project plan. For the first objective, we have deleted 4 different loci in the fungus that are suspected to be involved in apple fruit decay. Control strains have been generated and are being analyzed in vitro and in vivo in three different apple fruit cultivars Gala, Honeycrisp, and Fuji. For the second objective, we have shown that 2 different Penicillium spp. strains are non-pathogenic in apple fruit and when co-inoculated with apple rot fungi, blue mold decay is reduced. Whole genome sequences for both Penicillium spp strains and their metabolomes have been determined in culture. Additionally, it was shown that plastic storage bin material only binds blue mold spores at very high levels, and two new methods to kill spores on plastic bin material using novel physical and chemical methods. Related progress for the project has also been made in the effort to mitigate toxin and reduce decay caused by the blue mold fungus. Working with collaborators at Virginia Tech, several dsRNA constructs, to serve as molecular switches to shut off patulin production and reduce blue mold decay, have been designed, synthesized, and purified. Next steps will be conducted in vitro and in vivo and assay patulin and decay levels in infected fruit with the blue mold fungus. We also identified and characterized several new blue mold fungal isolates with fungicide resistance to one, two and three of the chemistries on the market from commercial East and West coast apple packing facilities. Whole genome sequence was obtained from the resistant isolates and they were assembled, annotated, and mined for markers that indicate resistance to specific postharvest fungicides. A new marker for thiabendazole resistance was identified that was previously unknown.
Accomplishments
1. Reducing food waste and loss of stored pome fruit. Blue mold results in economic losses, increases food waste and occurs during storage. It is caused by a fungus that also produces a toxin (patulin) that is harmful to humans. ARS researchers in Beltsville, Maryland, in collaboration with Cornell University in Geneva, New York, and Penn State University in Biglerville, Pennsylvania, evaluated new methods to reduce blue mold spores from bin surfaces. Before this work was conducted, industry did not know the importance of bin sanitation, the positive impact it has on decay management and practical ways to sanitize both wood and plastic storage bins. The treatments are applicable for both conventional and organic production practices and are being adopted by industry to reduce blue mold, ensure fruit quality, and reduce patulin occurrence.
Review Publications
Jurick II, W.M., Choi, M., Gaskins, V.L., Peter, K.A., Cox, K.D. 2023. Would you like wood or plastic? Bin material, sanitation treatments, and inoculum holding capacity impacts blue mold decay of stored apple fruit. Plant Disease. 107:1177-1182. https://doi.org/10.1094/PDIS-05-22-1045-RE.
Jurick II, W.M., Messinger, L., Wallis, A., Peter, K.A., Villani, S.M., Bradshaw, M.J., Bartholomew, H.P., Buser, M.D., Acimovic, S.G., Fonseca, J.M., Cox, K.D. 2022. PATHMAP (Pathogen And Tree fruit Health MAP): A smart phone app and interactive dashboard to record and map tree fruit diseases, disorders, and insect pests. PhytoFrontiers. 2(4):331-338. https://doi.org/10.1094/PHYTOFR-06-22-0070-TA.
Vasic, M., Vico, I., Jurick Ii, W.M., Duduk, B., Duduk, N. 2022. The dual nature of Lambertella corni-maris as an apple fruit pathogen and antagonist of Monilinia spp. PhytoFrontiers. 21.Article 91. https://doi.org/10.1007/s11557-022-01841-w.
