ARS | Publication request: A CAROTENOID BIOSYNTHESIS FUNCTION MAP IN CARROT

Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: June 15, 2003
Publication Date: August 8, 2003
Citation: Just, B., Santos, C., Simon, P.W. 2003. A carotenoid biosynthesis function map in carrot [abstract]. HortScience. 38:717.

Technical Abstract: Carotenoid pigments are responsible for the familiar orange color of carrot roots as well as the bright orange, red, and yellow colors of plant organs such as fruits and flowers in other species. Carotenoids also play an important role in protecting the photosynthetic apparatus in leaf tissue. The carotenoid biosynthetic pathway is highly conserved among plant species. 1- and a- carotene are the primary pigments in orange carrot roots. Yellow carrots accumulate xanthophylls (oxygenated carotenes), red carrots accumulate lycopene (the direct precursor to a- and 3- carotene), and white carrots accumulate no detectable pigments. We have generated a carotenoid biosynthesis function map in carrot on which we have placed fifteen putative carotenoid biosynthetic enzyme genes. The map is based on the F2 progeny of a cross between Queen Anne's Lace (QAL), a wild white carrot and B0493, a USDA orange inbred. We developed gene specific STS primers from gene sequences available for carrot or other species. In most cases, we used single nucleotide polymorphisms (SNPs) to map the genes. We mapped fifteen genes on seven of the nine carrot linkage groups. The same population was used in an earlier QTL study and we are identifying genes in the pathway that may serve as candidate genes for some of the QTL detected based on close linkage. We are currently investigating some of these candidate genes in F3 and F4 derivative populations of the cross. In addition, these genes can serve as anchor loci to identify homologous linkage groups in other carrot mapping projects. This work is part of a larger effort to better understand the genetics behind different pigment patterns in carrot.