Identification and characterization of MYB‐bHLH‐WD40 regulatory complexes controlling proanthocyanidin biosynthesis in strawberry (Fragaria × ananassa) fruits. Issue 2 (16th November 2012)

• Record Type: Journal Article
• Authors: Schaart, Jan G.; Dubos, Christian; Romero De La Fuente, Irene; van, Adèle M. M. L.; de, Ric C. H.; Jonker, Harry H.; Xu, Wenjia; Routaboul, Jean‐Marc; Lepiniec, Loïc; Bovy, Arnaud G.
• Is Part Of: New phytologist. Volume 197:Issue 2(2013)
• Page Start: 454
• Page End: 467
• Publication Date: 2012-11-16
• Subjects: Botany -- Periodicals; 580
• DOI: 10.1111/nph.12017
• Languages: English
• ISSNs: 0028-646X

Abstract

<abstract abstract-type="main" id="nph12017-abs-0001"> <title>Summary</title> <p> <list id="nph12017-list-0001" list-type="bullet"> <list-item> <p>Strawberry (<italic>Fragaria </italic>× <italic>ananassa</italic>) fruits contain high concentrations of flavonoids. In unripe strawberries, the flavonoids are mainly represented by proanthocyanidins (PAs), while in ripe fruits the red‐coloured anthocyanins also accumulate. Most of the structural genes leading to PA biosynthesis in strawberry have been characterized, but no information is available on their transcriptional regulation. In <italic>Arabidopsis thaliana</italic> the expression of the PA biosynthetic genes is specifically induced by a ternary protein complex, composed of AtTT2 (AtMYB123), AtTT8 (AtbHLH042) and AtTTG1 (WD40‐repeat protein).</p> </list-item> <list-item> <p>A strategy combining yeast‐two‐hybrid screening and agglomerative hierarchical clustering of transcriptomic and metabolomic data was undertaken to identify strawberry PA regulators.</p> </list-item> <list-item> <p>Among the candidate genes isolated, four were similar to <italic>AtTT2</italic>, <italic>AtTT8</italic> and <italic>AtTTG1</italic> (<italic>FaMYB9</italic>/<italic>FaMYB11</italic>, <italic>FabHLH3</italic> and <italic>FaTTG1</italic>, respectively) and two encode putative negative regulators (<italic>FaMYB5</italic> and <italic>FabHLH3∆</italic>). Interestingly, <italic>FaMYB9</italic>/<italic>FaMYB11</italic>, <italic>FabHLH3</italic> and <italic>FaTTG1</italic> were found to complement the <italic>tt2‐1</italic>, <italic>tt8‐3</italic> and <italic>ttg1‐1 transparent testa</italic> mutants, respectively. In addition, they interacted in yeast and activated the <italic>Arabidopsis </italic><italic>BANYULS</italic> (anthocyanidin reductase) gene promoter when coexpressed in <italic>Physcomitrella patens</italic> protoplasts.</p> </list-item> <list-item> <p>Taken together, these results demonstrated that <italic>FaMYB9</italic>/<italic>FaMYB11</italic>, <italic>FabHLH3</italic> and <italic>FaTTG1</italic> are the respective functional homologues of <italic>AtTT2</italic>, <italic>AtTT8</italic> and <italic>AtTTG1</italic>, providing new tools for modifying PA content and strawberry fruit quality.</p> </list-item> </list> </p> </abstract>