1: Develop effective biologically based systems for managing postharvest disease of temperate fruit crops. 1.A. Establish a biocontrol system to control brown rot of stone fruits. 1.B. Determine the cytological aspects of resistance in wild apple fruit from Kazakhstan to blue mold. 1.C. Develop a biocontrol management system for gray mold and anthracnose of strawberry high-tunnel production utilizing UV-C and microbial antagonists. 2: Develop knowledge base on the biology of postharvest biocontrol systems for use in selecting superior antagonists and to improve the overall efficacy of biocontrol agents. 2.A. Determine the effect of yeast induced reactive oxygen species (ROS) on host resistance. 2.B. Determine mechanisms associated with biocontrol of brown rot of stone fruits.
Research is focused on reducing the need of using postharvest fungicides in fruit production. It includes developing postharvest biological control of brown rot latent infections of stone fruits, basic studies on biocontrol systems, explaining the cytological basis for the resistance of Malus sieversii (‘Kazak’) apples to blue mold, and using LED lights to reduce gray mold and anthracnose of strawberries in high tunnel cultures. The seasonality of fruit availability allows the project to address the different objectives. Biocontrol studies on stone fruits will be conducted in early summer, resistance research on Kazak apples in the fall, and biocontrol studies on strawberry during the winter. Biocontrol of latent infections will include scale-up tests under simulated commercial conditions and research explaining the mechanism of biocontrol. Resistance studies of ‘Kazak’ apples will focus on characterizing the biochemistry of wound responses. Strawberry research will involve determining the effect of different UV-LED wavelengths on survival of B. cinerea and Colletotrichum spp., and epiphytic microflora, its effect on plants, and the use of selected LED in combination with antagonists to reduce gray mold and anthracnose. Basic research on yeast-based biocontrol systems will determine the effect of reactive oxygen species (ROS) on the efficacy of yeast antagonists and the ability of yeast ROS to induce defense systems in apple. This research will give growers alternative biological tools to combat fruit diseases, improve the efficacy of biocontrol systems, and in the case of the Kazak work, provide new information for the basis of postharvest disease resistance in apple germplasm that can be used in breeding programs.
Effectiveness of the two antagonist mixtures against brown rot of plums was tested in a larger scale fruit dip application experiment on wounded Jo-Jo plums. One mixture reduced decay by almost 40% after an extended (11 days) incubation time. Planned additional experiments were not conducted due to over-maturation of the plums during government shutdown at the beginning of October 2013. The wound responses to Penicillum expansum were confirmed on four wild apple accessions and were conducted on six crosses of Gala with Malus sieversii. The responses on immune and resistant accessions were similar to the previous year; however, lesions on moderately susceptible and susceptible accessions were larger. A new strawberry flower petal methodology was developed to determine efficacy of various bacteria and yeasts in controlling Botrytis cinerea infection of petals. Using this method, two very effective antagonists were selected for application to strawberry plants after UV-C irradiation in high tunnels. A new strawberry leaf disc assay was developed to determine efficacy of UV-C treatment in controlling powdery mildew caused by Podosphaera aphanis on strawberry plants. The UV-C treatment completely controlled powdery mildew at doses previously determined to be safe for strawberry plants. The UV-C did not affect leaf photosynthesis. A variety of experiments have been completed to examine the role of various stresses on the production of ROS in host fruit tissues and yeast biocontrol agents. These results have been summarized and published.
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Liu, J., Sui, Y., Wisniewski, M.E., Droby, S., Liu, Y. 2013. Utilization of antagonistic yeasts to control postharvest fungal diseases of fruits. International Journal of Food Microbiology. 167:153-160.
Janisiewicz, W.J., Jurick II, W.M., Peter, K.A., Kurtzman, C.P., Buyer, J.S. 2014. Yeasts associated with plums and their potential for controlling brown rot after harvest. Yeast. 31:207-218.
Hershkovitz, V., Sela, N., Tah-Salaime, L., Liu, J., Rafael, G., Kessler, C., Aly, R., Levi, M., Wisniewski, M.E., Droby, S. 2013. De-novo assembly and characterization of the transcriptome of Metschnikowia fructicola reveals differences in gene expression following interaction with Penicillium digitatum and grapefruit peel. Biomed Central (BMC) Genomics. p. 1-13.
Zhao, W., Wisniewski, M.E., Wang, W., Liu, J., Liu, Y. 2014. Heat-induced oxidative injury contributes to inhibition of Botrytis cinerea spore germination and growth. World Journal of Microbiology and Biotechnology. 30:951-957.
Liu, J., Wisniewski, M.E., Artlip, T.S., Sui, Y., Jiang, A., Droby, S., Norelli, J.L., Hu, W. 2013. The potential role of PR-8 gene of apple fruit in the mode of action of yeast antagonist, Candida oleophila, in postharvest biocontrol of Botrytis cinerea. Postharvest Biology and Technology. 85:203-209.
Janisiewicz, W.J., Conway, W.S., Biggs, A.R., Jurick Ii, W.M., Vico, I. 2013. Biological characterization of Monilinia fructicola isolates from stone fruits in eastern West Virginia. Canadian Journal of Plant Pathology. 35(3):315-327.