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Steele R. Jacob

Bio: Steele R. Jacob is an academic researcher. The author has contributed to research in topics: Promoter & Malus. The author has an hindex of 1, co-authored 1 publications receiving 689 citations.
Topics: Promoter, Malus, Anthocyanin, MYB

Papers
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Journal ArticleDOI
TL;DR: It is concluded that MdMYB1 coordinately regulates genes in the anthocyanin pathway and the expression level of this regulator is the genetic basis for apple skin color.
Abstract: Anthocyanins are secondary metabolites found in higher plants that contribute to the colors of flowers and fruits. In apples (Malus domestica Borkh.), several steps of the anthocyanin pathway are coordinately regulated, suggesting control by common transcription factors. A gene encoding an R2R3 MYB transcription factor was isolated from apple (cv Cripps' Pink) and designated MdMYB1. Analysis of the deduced amino acid sequence suggests that this gene encodes an ortholog of anthocyanin regulators in other plants. The expression of MdMYB1 in both Arabidopsis (Arabidopsis thaliana) plants and cultured grape cells induced the ectopic synthesis of anthocyanin. In the grape (Vitis vinifera) cells MdMYB1 stimulated transcription from the promoters of two apple genes encoding anthocyanin biosynthetic enzymes. In ripening apple fruit the transcription of MdMYB1 was correlated with anthocyanin synthesis in red skin sectors of fruit. When dark-grown fruit were exposed to sunlight, MdMYB1 transcript levels increased over several days, correlating with anthocyanin synthesis in the skin. MdMYB1 gene transcripts were more abundant in red skin apple cultivars compared to non-red skin cultivars. Several polymorphisms were identified in the promoter of MdMYB1. A derived cleaved amplified polymorphic sequence marker designed to one of these polymorphisms segregated with the inheritance of skin color in progeny from a cross of an unnamed red skin selection (a sibling of Cripps' Pink) and the non-red skin cultivar Golden Delicious. We conclude that MdMYB1 coordinately regulates genes in the anthocyanin pathway and the expression level of this regulator is the genetic basis for apple skin color.

837 citations


Cited by
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TL;DR: A better knowledge of the regulatory mechanisms of the flavonoids pathway is likely to favour the development of new biotechnological tools for the generation of value-added plants with optimized flavonoid content.
Abstract: Flavonoids are secondary metabolites involved in several aspects of plant development and defence. They colour fruits and flowers, favouring seed and pollen dispersal, and contribute to plant adaptation to environmental conditions such as cold or UV stresses, and pathogen attacks. Because they affect the quality of flowers (for horticulture), fruits and vegetables, and their derivatives (colour, aroma, stringency, etc.), flavonoids have a high economic value. Furthermore, these compounds possess pharmaceutical properties extremely attractive for human health. Thanks to easily detectable mutant phenotypes, such as modification of petal pigmentation and seeds exhibiting transparent testa, the enzymes involved in the flavonoid biosynthetic pathway have been characterized in several plant species. Conserved features as well as specific differences have been described. Regulation of structural gene expression appears tightly organized in a spatial and temporal way during plant development, and is orchestrated by a ternary complex involving transcription factors from the R2R3-MYB, basic helix-loop-helix (bHLH), and WD40 classes. This MYB-bHLH-WD40 (MBW) complex regulates the genes that encode enzymes specifically involved in the late steps of the pathway leading to the biosynthesis of anthocyanins and condensed tannins. Although several genes encoding transcription factors from these three families have been identified, many gaps remain in our understanding of the regulation of this biosynthetic pathway, especially about the respective roles of bHLH and WD40 proteins. A better knowledge of the regulatory mechanisms of the flavonoid pathway is likely to favour the development of new biotechnological tools for the generation of value-added plants with optimized flavonoid content.

908 citations

Journal ArticleDOI
TL;DR: A simplified model for the different regulatory networks involved with anthocyanin production in fruit is proposed and shows clear links between the developmental regulatory network and the specific regulators of anthcyanin biosynthesis during fruit ripening.

789 citations

Journal ArticleDOI
TL;DR: Understanding of the regulation of anthocyanin synthesis in flowers and fruits is broadened, indicating that a regulatory system based on the cooperation of MYB, bHLH and WD40 proteins that control floral and fruit pigmentation is common to many dicot species.

650 citations

Journal ArticleDOI
TL;DR: In apple, three recent papers describe the discovery of MYB genes activating skin, flesh and foliage anthocyanic colour as mentioned in this paper, which lead the way to new approaches in the breeding and biotechnological development of fruit with new colour patterns.

582 citations

Journal ArticleDOI
TL;DR: This review summarizes the current understanding of V-myb myeloblastosis viral oncogene homolog (MYB) proteins and their roles in the regulation of phenylpropanoid metabolism in plants.

569 citations