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United States Department of Agriculture

Agricultural Research Service

Title: Towards the Isolation of the Cauliflower Or Gene: Identification of Tightly Linked Molecular Markers for Map-Based Cloning

item Garvin, David

Submitted to: Carotenoid Symposium
Publication Type: Abstract Only
Publication Acceptance Date: January 6, 2002
Publication Date: N/A

Technical Abstract: Carotenoids are important for human health and well-being because they serve as the primary precursors of vitamin A synthesis. Therefore, it would be desirable to have the capability to increase levels of carotenoids in staple crops that form the principal basis of the human diet to combat vitamin A deficiency. The unique cauliflower (Brassica oleracea L. var. botrytis) Or gene causes significant levels of beta-carotene to accumulate in many plant tissues. As a first step toward its isolation, molecular mapping of the Or gene was conducted. Several AFLP markers were identified, with the most tightly linked flanking markers defining a 1.6 cM interval within which the Or gene resides. Further, one marker that cosegregates with the Or gene was identified. The AFLP markers were cloned and sequenced, and four were found to represent low-copy sequences in cauliflower that revealed polymorphisms when used for RFLP analysis. Comparisons between these marker sequences and the Arabidopsis thaliana genome sequence suggest that the ortholog of the Or gene is likely to reside on Arabidopsis chromosome 5. The most tightly linked AFLP markers have been converted into PCR-based markers, and high resolution genetic mapping and physical mapping of the Or gene is being undertaken to establish a framework for positional cloning of the Or gene. We expect that by isolating this gene, we will gain new insights into the processes that control carotenoid accumulation in plants. This in turn shall reveal novel strategies for modifying carotenoid content in other crops of greater importance to human diets.

Last Modified: 4/19/2015
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