2013 Annual Report
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.
Ultraviolet light (UV-C) was used to kill fungi that can cause decay of strawberry fruit. Under laboratory conditions using certain manipulations in applying UV-C, we achieved a much better kill of the fungi than using a standard irradiation method. Since the UV-C irradiation at high doses can be damaging to plants, results of our research allowed us to lower the amount of UV-C irradiation of plants below a threshold that causes injury and at the same time be strong enough to kill the fungus.
Developing alternative approaches to disease control is a critical objective of NP-303, Plant Diseases, due to consumer demands to lower exposure to chemicals and reduce the impact of agriculture on the environment. In the past decade, USDA-ARS has identified several species of yeasts that can be used as biocontrol agents against postharvest diseases of fruit. Despite these options, use of these products remains limited partly due to variable performance. Therefore, there is a need to better understand the biology of biocontrol systems (host-pathogen-biocontrol agent) in order to increase their efficacy under a wide array of environmental conditions. In the present study, the expression of an apple disease resistance gene (PR-8) in response to the grey mold pathogen (Botrytis cinerea) was examined and whether the secretion of the coded protein could enhance the biocontrol activity of a yeast was evaluated. The PR-8 gene from apple was cloned and put in a yeast expression system. Results indicated that PR-8 is upregulated in response to the grey mold pathogen and is also stimulated by a yeast biocontrol agent. Futhermore, when the gene was expressed in a yeast, the yeast inhibited the grey mold pathogen both in a test tube system and in apple fruit. This information will be used to develop strategies to increase natural resistance in harvested apple fruit and increase the efficacy of yeast biocontrol agents.
Jurick II, W.M., Vico, I., Gaskins, V.L., Whitaker, B.D., Garrett, W.M., Janisiewicz, W.J., Conway, W.S. 2012. Penicillium solitum produces a polygalacturonase isozyme in decayed ‘Anjou’ pear fruit capable of macerating host tissue in vitro. Mycologia. DOI:10.3852/11.119.
Jurick II, W.M., Vico, I., Gaskins, V.L., Janisiewicz, W.J., Peter, K.A. 2013. First Report of Neofusicoccum ribis causing postharvest decay of apple fruit from cold storage in Pennsylvania. Plant Disease. 97(7):999.
Jurick II, W.M., Vico, I., Gaskins, V.L., Janisiewicz, W.J., Peter, K.A. 2013. First report of Botryosphearia dothidea causing white rot on apple fruit in Maryland. Plant Disease. DOI: 10.1094/PDIS-01-13-0053-PDN.
Peter, K.A., Vico, I., Gaskins, V.L., Janisiewicz, W.J., Saftner, R.A., Jurick II, W.M. 2012. First report of Penicillium carneum causing blue mold on stored apples in the United States. Plant Disease. 96:1823.
Liu, J., Macarisin, D., Wisniewski, M.E., Sui, Y., Droby, S., Norelli, J.L., Hershkovitz, V. 2012. Production of hydrogen peroxide and expression of ROS generating genes in peach flower petals in response to host and non-host pathogens. Plant Pathology. 62:820-828.
Vero, S., Garmendia, G., Gonzalez, M., Bentacur, O., Wisniewski, M.E. 2012. Evaluation of yeasts obtained from Antarctic soil samples as biocontrol agents for the management of postharvest diseases of apple (Malus x domestica). Federation Of European Microbiological Societies Yeast Research. 13:189-199.