BUILDING CAPACITY IN FUNCTIONAL GENOMICS TO AUGMENT SUGAR METABOLISM FOR IMPROVING MUSCADINE GRAPE PRODUCT CHARACTERISTICS AND SUSTAINABILITY

The presence of adequate amount of natural sugar is important during berry development because they serve as a primary substrate as well as carbon backbone for the synthesis of secondary metabolites like phenolics, terpenes, organic acids, and others.Sugar content and composition of muscadine grape berry cannot be altered through traditional breeding because of genetic incompatibility between Bunch and muscadine grape species. Therefore, identification of gene/s and enzymes associated with high sugar accumulation and their regulator/s is crucial to effectively increase the sugar content of muscadine grape. Hence, we propose to take a functional genomics approach for identifying the molecular players such as genes, enzymes and their inhibitors that explain differences in sugar content/accumulation between muscadine and Bunch grape genotypes.This approach will help overcome the limitations of conventional breeding to increase muscadine grape sugar content, products characteristics, shelf life and market value.The specific objectives of this research are to: 1) Identify and characterize the genes and their transcripts primarily involved in sugar metabolism in muscadine and Bunch grape genotypes, 2) Determine differences in the expression of sugar metabolism related genes to identify the differentially expressed gene/s between the muscadine and Bunch grape genotypes, 3) Quantify the activity of enzymes associated with sugar metabolism in muscadine and Bunch grape genotypes to correlate with expression of identified candidate genes, 4) Confirm the role of the identified candidate gene/s in sugar metabolism using a heterologous model system through complementation test, 5) Establish the CRISPR/Cas9 gene-editing system for use in editing the candidate gene expression to develop a high-sugar muscadine grape genotype, and 6) Train African American and other minority students in functional genomics and CRISPR-Cas9 gene editing to develop a competent workforce for meeting the challenges of the 21st century.