United States of America, As Represented by the Secretary of Agriculture

Cornell University

Boyce Thompson Institute for Plant Research

Boyce Thompson Institute Inc.

David F Garvin

Joyce Van Eck

Julia Vrebalov

Li Li

Shan Lu

Diana M O'Halloran

The present invention relates to a nucleic acid construct having a nucleic acid molecule configured to silence &#x3b2;-carotene hydroxylase expression, and host cells, expression systems, plants, and plant seeds having the nucleic acid construct. The present invention also relates to a method of enhancing beta-carotene content by growing a transgenic plant from a plant or seed transformed with the construct.

Enhancement of beta-carotene content in plants

The cauliflower (L. var.) Or gene is a semi-dominant, single-locus mutation. It induces the accumulation of high levels of beta-carotene in various tissues that are normally devoid of carotenoids, turning them orange. Using a map-based cloning strategy, we identified a single candidate gene representing Or and successfully verified its identity by phenotypic complementation in the wild type cauliflower. The Or gene encodes a plastid membrane protein containing the DnaJ zinc figure domain. A likely gain-of-function mutation from a 4.3-kb retrotransposon insertion in the Or allele confers the orange phenotype in the mutant. Southern blot analysis revealed that Or is a single-copy sequence in the cauliflower genome. High level of expression of the Or gene and the protein was found in very young leaves, curds, and flowers at comparable abundance between wild type and the Or mutant. Or likely functions in regulating the differentiation of some non-photosynthetic plastids into chromoplasts, which provide the deposition 'sink' for carotenoid accumulation. Or orthologs with high degree of sequence homology were found in many other higher plants, including, tomato, maize, and rice. Successful phenotypic complementation of Or inprovides strong evidence that Or can work across species to enhance carotenoid accumulation in other important crops.

[object Object]

Growing community of inventors

Roseville, MN, United States of America

David F Garvin