Pecan (Carya illinoinensis) is a nut crop native to the United States and Mexico which is becoming an increasingly important crop globally. Juglandaceous nuts are uniquely high in antioxidants among nuts and a conversion equivalent derived from studies in mice indicates that consumption of 22-38 pecans per day may reverse metabolic disorder in an individual weighing 132 pounds, implying a role in a healthy diet. Despite this importance, relatively little is known about the molecular basis of pecan nut ontogeny compared to other nut crops, leading to difficulties in understanding the physiological issues which plague growers. Susceptibility to various biotic and abiotic disorders including pecan scab, vivipary, water split, and shuck decline are dependent upon the stage of development the pecan nut is in. To better understand the molecular basis and timing of pecan nut development, developmental time-course RNA-Seq was carried out on nuts collected from cultivars ‘Mahan’ (a large nut bearing pecan from Mississippi) and ‘Tiny Tim’ (a small nut bearing native pecan from Missouri) approximately biweekly through the growing season of 2022. Using this data, genes were grouped together into distinct developmental phases, connecting transcriptional changes to the already well-characterized ontogenic stages of pecan nut development.
