AtMYB12 regulates caffeoyl quinic acid and flavonol synthesis in tomato: expression in fruit results in very high levels of both types of polyphenol

• Published in: The Plant journal : for cell and molecular biology 2008-10, Vol.56 (2), p.316-326
• Main Authors: Luo, Jie, Butelli, Eugenio, Hill, Lionel, Parr, Adrian, Niggeweg, Ricarda, Bailey, Paul, Weisshaar, Bernd, Martin, Cathie
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Antioxidants; Antioxidants - metabolism; Arabidopsis - genetics; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Biological and medical sciences; Biotechnology; Botany; caffeoyl quinic acids; Carotenoids - biosynthesis; Cloning, Molecular; flavonoids; Flavonoids - biosynthesis; Flavonols - biosynthesis; Fruit - genetics; Fruit - metabolism; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression Regulation, Plant; Genetic engineering; Genetic technics; Lycopersicon esculentum; Lycopersicon esculentum - genetics; Lycopersicon esculentum - metabolism; metabolic engineering; Methods. Procedures. Technologies; Molecular Sequence Data; Pharmacology; Phenols; Phylogeny; Plants, Genetically Modified - genetics; Plants, Genetically Modified - metabolism; Plasmids; Polyphenols; Quinic Acid - analogs & derivatives; Quinic Acid - metabolism; Reverse Transcriptase Polymerase Chain Reaction; RNA, Plant - genetics; secondary metabolism; Sequence Alignment; Tomatoes; transcription factor; Transcription Factors - genetics; Transcription Factors - metabolism; Transformation, Genetic; Transgenic animals and transgenic plants; Transgenic plants
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313x.2008.03597.x

Plant polyphenolics exhibit a broad spectrum of health-promoting effects when consumed as part of the diet, and there is considerable interest in enhancing the levels of these bioactive molecules in plants used as foods. AtMYB12 was originally identified as a flavonol-specific transcriptional activator in Arabidopsis thaliana, and this has been confirmed by ectopic expression in tobacco. AtMYB12 is able to induce the expression of additional target genes in tobacco, leading to the accumulation of very high levels of flavonols. When expressed in a tissue-specific manner in tomato, AtMYB12 activates the caffeoyl quinic acid biosynthetic pathway, in addition to the flavonol biosynthetic pathway, an activity which probably mirrors that of the orthologous MYB12-like protein in tomato. As a result of its broad specificity for transcriptional activation in tomato, AtMYB12 can be used to produce fruit with extremely high levels of multiple polyphenolic anti-oxidants. Our data indicate that transcription factors may have different specificities for target genes in different plants, which is of significance when designing strategies to improve metabolite accumulation and the anti-oxidant capacity of foods.