Location: Sugarbeet and Potato Research
Project Number: 3060-21430-008-00-D
Project Type: In-House Appropriated
Start Date: Apr 16, 2020
End Date: Jun 9, 2021
Objective 1: Delineate and integrate the molecular processes that control cytokinin content and their biological activities during tuber dormancy progression and wound-healing. Sub-Objective 1-1: Determine changes in tuber meristem cytokinin content and expression of genes encoding cytokinin biosynthetic enzymes during dormancy progression. Sub-Objective 1-2: Determine changes in the expression of cytokinin-responsive histidine kinase genes and the acquisition of cytokinin sensitivity during tuber dormancy progression. Sub-Objective 1.3: Determine changes in cytokinin content and the expression of genes encoding key cytokinin metabolic enzymes in tuber tissues following mechanical wounding. Objective 2: Quantify nitric oxide release during potato storage and handling and determine nitric oxide involvement in tuber dormancy progression and wound-healing. Sub-Objective 2.1: Determine the release and role of NO in potato tuber dormancy exit. Sub-Objective 2.2: Determine the release and role of NO in the potato tuber wound-healing response. Objective 3: Determine the effects of postharvest storage on process quality and nutritional composition of advanced breeding lines in collaboration with public potato breeding programs (non-hypothesis driven). Sub-objective 3.1: Determine storage and processing characteristics of advanced breeding lines. Sub-objective 3.2: Screen advanced potato breeding lines for cold storage potential. Objective 4: Determine the total antioxidant and ascorbic acid (vitamin C) contents of advanced breeding clones at harvest and during temperature-controlled storage (non-hypothesis driven). Objective 5: Identify and characterize the physiological and molecular mechanisms that regulate and maintain meristem dormancy in potato tubers and evaluate strategies to inhibit tuber sprouting during storage.
Worldwide, the potato ranks fourth among the major food crops. Global potato production exceeds 364 million metric tons (FAOSTAT, March, 2013) and U.S. production exceeds 437 million cwt (USDA-NASS, January, 2013) of which over 400 million cwt worth an estimated $2.01 billion are harvested in the fall. Over 70% of the fall potato crop is placed into storage for year-round use. Unlike other major food crops, potatoes are stored in a fully hydrated and highly perishable form. Postharvest losses routinely approach 10% of the stored crop and occur through both physiological and disease-related processes. Two of the most important physiological processes affecting potato storage and market quality are dormancy/sprouting and wound-healing. Despite the severity of these losses, management strategies and technologies employed to combat these problems were empirically derived, are several decades old and do not effectively meet today’s consumer or industry demands to control damage, minimize physiological deteriorations, and reduce disease problems. Further improvements in postharvest storage technologies are hindered by ignorance of the biological mechanisms underlying these physiological processes. The goals of this project are to identify critical molecular, biochemical and physiological mechanisms controlling tuber dormancy/sprout growth and wound-healing and, ultimately, to genetically, chemically, or physically manipulate these rate-limiting processes to develop improved methods to maintain potato nutritional and processing quality during storage. Specific goals are: 1) Identify the cognate processes that control cytokinin content and activity during postharvest storage/wound-healing, and 2) Determine the involvement of nitric oxide in tuber dormancy progression and wound-healing.