Comparative analysis of Cucurbita pepo metabolism throughout fruit development in acorn squash and oilseed pumpkin. (21st September 2016)

• Record Type: Journal Article
• Authors: Wyatt, Lindsay E; Strickler, Susan R; Mueller, Lukas A; Mazourek, Michael
• Is Part Of: Horticulture research. Volume 3(2016)
• Publication Date: 2016-09-21
• Subjects: Plant breeding -- Plant development -- Secondary metabolism; Horticulture -- Research -- Periodicals; 635.072
• DOI: 10.1038/hortres.2016.45
• Languages: English
• ISSNs: 2052-7276

Abstract

Abstract: Both the fruit mesocarp and the seeds of winter squash can be used for consumption, although the focus of breeding efforts varies by cultivar. Cultivars bred for fruit consumption are selected for fruit mesocarp quality traits such as carotenoid content, percent dry matter, and percent soluble solids, while these traits are essentially ignored in oilseed pumpkins. To compare fruit development in these two types of squash, we sequenced the fruit transcriptome of two cultivars bred for different purposes: an acorn squash, 'Sweet REBA', and an oilseed pumpkin, 'Lady Godiva'. Putative metabolic pathways were developed for carotenoid, starch, and sucrose synthesis in winter squash fruit and squash homologs were identified for each of the structural genes in the pathways. Gene expression, especially of known rate-limiting and branch point genes, corresponded with metabolite accumulation both across development and between the two cultivars. Thus, developmental regulation of metabolite genes is an important factor in winter squash fruit quality. Abstract : Fruit development: Towards multi-purpose pumpkins Comparing the genes active in two types of winter squash reveals the pathways underpinning fruit and seed development. The winter squash, Cucurbita pepo, has traditionally been bred along two diverging pathways, culminating in edible fruits such as acorn squashes, and oil-rich seeds such as those of oilseed pumpkins. A US team led by Michael Mazourek of Cornell University, New York, realized that winter squash provide an ideal resource for comparative studies of fruit development. By sequencing the genes actively encoding proteins at any given time (the 'transcriptome') of both acorn squash and oilseed pumpkin, they revealed differences in genetic control correlated with metabolic processes and fruit characteristics such as sugar, starch and pigment content. The authors hope this understanding could ultimately lead to developing dual-purpose pumpkins that can be harvested for both fruit and seeds.