ARS | Publication request: Inheritance and mapping of the ore gene controlling the quantity of ß-carotene in cucumber (Cucumis sativus L.) endocarp

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 29, 2011
Publication Date: August 17, 2011
Citation: Bo, K., Song, H., Shen, J., Qian, C., Staub, J.E., Simon, P.W., Lou, Q., Chen, J. 2011. Inheritance and mapping of the ore gene controlling the quantity of ß-carotene in cucumber (Cucumis sativus L.) endocarp. Molecular Breeding. 30(1):335-344.

Interpretive Summary: While an excellent food, cucumber is a crop that has a relatively low nutrient content. Unusual cucumbers with orange flesh, giving them an appearance similar to orange-fleshed melons, can be found in parts of Asia. The orange color gives these cucumbers a high nutrient content since they have a relatively high content of beta-carotene, an antioxidant that is converted to vitamin A upon ingestion. To develop orange-fleshed cucumbers for other production areas of the world, they have been intercrossed with typical white-fleshed cucumbers of the U.S. and Europe to develop orange-fleshed cucumbers adapted for several global markets. The genetic basis of orange flesh color has been studied, but the gene(s) controlling this trait have not been well-described. This study determined the inheritance and located the chromosome region of major gene that controls orange flesh color of cucumber. This information provides insights into the genetics of this important trait, and provides plant breeders with biotechnological tools to more efficiently breed for orange flesh color of cucumbers. This research is of interest to plant breeders, geneticists, nutritionists, and the food industry.

Technical Abstract: The metabolic precursor of vitamin A, ß-carotene, is essential for human health. The gene(s) controlling ß- carotene quantity (QßC) has been introgressed from Xishuangbanna gourd (XIS, possessing ß-carotene; Cucumis sativus L. var. xishuangbannanesis Qi et Yuan; 2n = 2x = 14) into cultivated cucumber (no ß- carotene; Cucumis sativus L.). To determine the inheritance of QßC in cucumber fruit endocarp, F1 progeny and a set of 124 F7 recombinant inbred lines (RILs) derived from the cultivated cucumber line CC3 and XIS line SWCC8 were evaluated for QßC during 2009 and 2010 in Nanjing, China. Segregation analysis revealed that endocarp QßC of greenhouse-grown fruit was controlled by a single recessive gene. Further, marker analysis indicated the gene controlling QßC was linked to seven SSR markers on linkage group 3, where their order was SSR20710 –SSR19511 –SSR15419 –SSR07706 –ore –SSR23231 –SSR11633 –SSR20270 . These markers and the putative candidate gene were mapped to cucumber chromosome 3DS. An evaluation of 30 genetically diverse cucumber lines indicated that marker SSR07706 has utility in further genetic analyses of the QßC orange endocarp gene, designated ore . Moreover, the markers defined herein may have utility for marker-assisted selection directed towards the development of cucumber germplasm with high fruit ß- carotene content.