DEVELOPMENT OF ADVANCED PHENOTYPING AND MOLECULAR TOOLS TO IMPROVE QUALITY TRAITS IN FRUIT AND VEGETABLES

Long-term Goal: Use of advanced DNA based and phenotyping strategies to select new cultivars of fruits and vegetables with improved quality, to support North Carolina and nationwide/global production for fresh market and processing industry.Problem Statement: In the last two decades, plant breeders and geneticists have made extensive efforts to advance use of DNA based tools and high-throughput phenotyping methods to improve fruits and vegetables for numerous economically important traits, like disease resistance, yield, and storage life (Sharma et al., 2019). As a consequence of climate changes, extensive efforts are currently ongoing to study genetic mechanisms that contribute to tolerance for abiotic stresses such as drought tolerance and nutrient deficiency (Taunk et al., 2019). Overall, these efforts are contributing to develop production systems that are more sustainable from an economic and environmental perspective. However, a gap still exists in advancing breeding strategies to improve the quality of fruit and vegetables.This project will focus on carrots and blueberries. The U.S. is the world's largest producer of blueberries and 3rd largest producer of carrots (FAO STAT, 2018). North Carolina ranks 7th in U.S. blueberry production. The outcomes of the previous five-year Hatch project (NC09826) led by Dr. Iorizzo contributed to establish high quality genomic resources (Iorizzo et al., 2016, Iorizzo et al., 2018, Iorizzo et al. 2019a-b; Bostan et al., 2019; Iorizzo et al., 2020), understand the diversity and some genetic mechanisms controlling chemical composition in blueberry and carrot (Iorizzo et al., 2019, Curaba et al., 2020, Mengist et al., 2020), and identify industry breeding priorities (Gallardo et al., 2018a-b). For instance, in response to breeding surveys, blueberry stakeholders from NC, and the US in general, identified fruit quality traits, such as firmness, sensory profile (e.g. flavor) and shelf-life as the most important traits to improve for continued success (Gallardo et al., 2018a-b). For carrot, health properties, and nutritional quality were among the top four areas for which the carrot industry suggested there be more research on (Simon et al., 2018). To leverage the outcomes of the previous five-year Hatch project, the research program described herein will focus on expanding the state of knowledge about the molecular and genetic basis controlling characteristics affecting quality in carrot and blueberry.Quality of fruit and vegetables, including blueberry and carrot depend on fruit characteristics such as appearance, texture, chemical composition. Size, color, free of external defects, affect the decisional process that consumer make before electing to buy a product. For instance, fruit appearance characteristics such as a large fruit size in blueberry are associated with higher quality since these attributes are preferred by consumers and are used to grade blueberries (USDA-AMS, 1997). Texture and chemical composition directly affect the aroma, flavor, and taste, and consequently they determined the consumer eating experience, their preferences and their decision to re-purchase that product (Schwieterman et al., 2914; Christensen 1983; Mditshwa et al., 2017). In a consumer study with blueberries, sensory texture descriptors of poor quality, such as mealiness, seediness, and toughness, negatively affected consumer likelihood of purchase (Gilbert et al., 2014). Texture can also affect the resistance of the fruit to damage (e.g. bruising) during handling, mechanical harvest and processing [Olmstead and Finn, 2014), in addition to overall fruit quality stability during storage (shelf life) (Giongo et al., 2013). Chemical composition, also determine the beneficial effect that a plant metabolite (nutrient and bioactive) can have on human health (Martin and Li, 2017). Today, a growing body of evidence indicates that plant compounds can provide health benefits beyond the traditional nutrients they contain resulting in the definition of functional nutrients (Slavin and Lloyd, 2012; Bakovic et al., 2011). Functional nutrients or phytochemicals are of increasing interest in the prevention and/or treatment of at least four of the leading causes of death in the United States: cancer, diabetes, cardiovascular disease and hypertension (Potter and Steinmetz et al., 1996). Both blueberry and carrot germplasm, include genotypes rich in phytochemicals such as anthocyanins (both carrot and blueberry) and carotenoids (carrot). The health-beneficial effects associated with these metabolites have increased carrot and blueberry production and consumption in the last decade (Simon et al., 2019; Fulcher et al., 2015). In addition, plant phytochemicals that can be used as natural colorants greatly appeals to consumers opening a new market opportunities for those crops (Baranski et al., 2016).To support the production of new carrot and blueberry varieties with improved quality and nutritional value it is important to facilitate the identification and characterization of genes controlling fruit and root characteristics and phytochemical accumulation that affect quality. This will provide molecular tools to facilitate the introgression and pyramiding of these traits in breeding programs.Objectives:The objectives of this project are to:Objective 1: Identify molecular markers associated with fruit and root characteristics and quality attributes;Objective 2: Identify and characterize candidate genes controlling fruit and root characteristics and quality attributes;Objective 3. Develop high-throughput molecular and phenotyping assay to select for high value fruit and root characteristicsThis project is designed to interface with breeding projects on carrot (P. Simon, USDA) and blueberry (https://www.vaccinium.org/vaccap team ) and geneticist at the National Clonal Germplasm Repository (N. Bassil, USDA). It is also designed to collaborate with experts in metabolite characterization (M.A. Lila, NCSU), post-harvest physiology (P. Perkins Veazie, NCSU) and food science (M.G. Ferruzzi, NCSU). The project will complement current small fruits and vegetables breeding programs while filling gaps between plant breeding, fruit and vegetable quality and nutritional genomics.