Location: Innovative Fruit Production, Improvement, and Protection
2020 Annual Report
Objectives
Objective 1: Develop alternative systems for the management of postharvest
diseases that can be used on a variety of fruit crops and production systems,
including packinghouses, urban horticulture, vertical farming, and controlled
environment growing systems. [NP303, C3, PS3B]
• Sub-objective 1.A. Control of strawberry diseases using UV-C/dark Period/antagonist treatment.
• Sub-objective 1.B. Control of postharvest brown rot of stone fruits.
Objective 2: Develop microbiome-based approaches and molecular tools to increase
postharvest disease resistance and/or decrease pathogen virulence. [NP303, C3,
PS3B]
• Sub-objective 2.A. Identification of molecular mechanisms responsible for
resistance to the postharvest pathogens Penicillium expansum and Colletotrichum
acutatum to facilitate the development of markers for use in screening for
resistant crosses.
• Sub-objective 2.B. Characterize the microbiome on fruit crops as it relates to
pre-harvest management practices and postharvest treatments.
Approach
Research is focused on reducing the need to use postharvest fungicides in fruit
production. It includes developing an integrated system to enhance control of
Botrytis cinerea, Colletotrichum spp., and Podoshpaera aphanis in strawberry by
combining UV-C irradiation with a dark period and application of biocontrol agents. The system is designed for field use and protective culture, including high tunnels and indoor urban agricultural production. The research will also determine the effect of UV-C/dark period/antagonist treatment on the quality of strawberry fruit. Genes associated with resistance to blue mold and anthracnose disease in wild apple germplasm will be determined, including the role of constitutive phenolic compounds, to facilitate the development of markers for use in screening for resistant crosses in apple breeding programs. Integrated control of brown rot disease of plums originating in wounds and from latent infections, currently an intractable disease control problem, will be developed using Generally Regarded as Safe (GRAS) substances and heat treatments. Amplicon-based analysis of the microbial community of apple fruit and strawberry fruit and leaves, and other fruit crops will be conducted to determine the impact of pre-harvest management practices and/or postharvest treatments on bacterial and fungal communities. This research is expected to identify safe and effective strategies that reduce disease without negatively impacting fruit quality and are based on the manipulation of the natural microflora or through the purposeful design of microbial consortia. Collectively, the results of the proposed research will directly and indirectly contribute to the provision of control alternatives based on “green” technologies to combat postharvest diseases of critical importance to fruit growers and processors. The developed technology will also address consumer demands to reduce synthetic chemical residues in food.
Progress Report
This is the final report for the project 8080-22000-011-00D which ended June 15, 2020. New NP305 OSQR approved project 8080-21000-032-00D, entitled "Integrated Production and Automation Systems for Temperate Fruit Crops", has been established.
Our preliminary study indicated that krypton chloride (Kr-Cl) lamps emitting Far UV at 220 nm are much more effective than conventional UV-C lamps (254 nm) in killing fungi. Thus, we conducted a more in depth study to determine the usefulness of Far UV light in killing pathogens causing diseases of strawberry plants and the effect of the Far UV on plant growth and productivity. We focused first on the effect of the Far UV-C on killing conidia of major pathogens of strawberry that cause anthracnose, gray mold and blue mold, and on chlorophyll, plant photosynthesis, pollen viability, germination and tube growth, and fruit set. We found in in vitro plate assay that irradiation with Far UV for only 15 seconds killed most conidia of fungi causing gray mold (B. cinerea), blue mold (P. expansum), and anthracnose (six species of Colletotrichum complex) of strawberries. To obtain comparable results with conventional UV irradiation, the conidia had to be irradiated three to four times longer. We also found no negative effect of Far UV on strawberry plant photosynthesis, pollen germination, tube growth in artificial medium, and through a pistil all the way to the ovary at the irradiation doses of 15 sec twice or five times per week. As irradiation doses increased (to 30 and 60 sec) plants become gradually more stunted and dark green. Irradiation for 30 sec of harvested strawberries artificially inoculated with standard concentration of conidia of gray mold fungus controlled the disease. High effectiveness of the Far UV in killing fungal pathogens makes this type of irradiation commercially very attractive because much larger field areas could be treated within a given period of time in comparison to conventional UV-C treatment. Additional test on the effectiveness of Far UV in controlling gray mold, anthracnose, and powdery mildew on strawberry plants, as well as the effect of this treatment on fruit yield, are warranted.
Accomplishments
Review Publications
Wisniewski, M.E., Droby, S. 2019. The postharvest microbiome: the other half of sustainability. Biological Control. https://doi.org/10.1016/j.biocontrol.2019.104025.
Gonda, M., Garmendia, G., Rufo, C., Pelanez, A.L., Wisniewski, M.E., Droby, S., Vero, S. 2019. Biocontrol of Aspergillus flavus in ensiled sorghum by water kefir microorganisms. Microorganisms. https://doi.org/10.3390/microorganisms7080253.
Zajc, J., Cernosa, A., Di Francesco, A., Castoria, R., De Curtis, F., Lima, G., Badri, H., Jijakli, H., Ippolito, A., Gostincar, C., Zalar, P., Gunde-Cimerman, N., Janisiewicz, W.J. 2020. Characterization of Aureobasidium pullulans isolates selected as biocontrol agents against fruit decay pathogens. Fungal Genomics and Biology. 10(163):1-13.
