title: The R2R3MYB VvMYBPA1 from grape reprograms the phenylpropanoid pathway in tobacco flowers.
abstract: This work shows that, in tobacco, the ectopic expression of VvMYBPA1 , a grape regulator of proanthocyanidin biosynthesis, up- or down-regulates different branches of the phenylproanoid pathway, in a structure-specific fashion. Proanthocyanidins are flavonoids of paramount importance for animal and human diet. Research interest increasingly tilts towards generating crops enriched with these health-promoting compounds. Flavonoids synthesis is regulated by the MBW transcriptional complex, made of R2R3MYB, bHLH and WD40 proteins, with the MYB components liable for channeling the complex towards specific branches of the pathway. Hence, using tobacco as a model, here, we tested if the ectopic expression of the proanthocyanidin regulator VvMYBPA1 from grape induces the biosynthesis of these compounds in not-naturally committed cells. Here, we show, via targeted transcriptomic and metabolic analyses of primary transgenic lines and their progeny, that VvMYBPA1 alters the phenylpropanoid pathway in tobacco floral organs, in a structure-specific fashion. We also report that a modest VvMYBPA1 expression is sufficient to induce the expression of both proanthocyanidin-specific and early genes of the phenylpropanoid pathway. Consequently, proanthocyanidins and chlorogenic acids are induced or de novo synthetised in floral limbs, tubes and stamens. Other phenylpropanoid branches are conversely induced or depleted according to the floral structure. Our study documents a novel and distinct function of VvMYBPA1 with respect to other MYBs regulating proanthocyanidins. Present findings may have major implications in designing strategies for enriching crops with health-promoting compounds.
authors.affiliation: CNR, Institute of Biosciences and Bioresources, Perugia Division, Via Madonna Alta, 130 06128, Perugia, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Passeri
authors.affiliation: Research and Innovation Center, Fondazione Edmund Mach - IASMA, via E. Mach 1, 38010, San Michele All'adige, Italy.
authors.forename: Stefan
authors.initials: S
authors.lastname: Martens
authors.affiliation: Research and Innovation Center, Fondazione Edmund Mach - IASMA, via E. Mach 1, 38010, San Michele All'adige, Italy.
authors.forename: Elisabete
authors.initials: E
authors.lastname: Carvalho
authors.affiliation: CNR, Institute of Biosciences and Bioresources, Perugia Division, Via Madonna Alta, 130 06128, Perugia, Italy.
authors.forename: Chantal
authors.initials: C
authors.lastname: Bianchet
authors.affiliation: CNR, Institute of Biosciences and Bioresources, Perugia Division, Via Madonna Alta, 130 06128, Perugia, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Damiani
authors.affiliation: CNR, Institute of Biosciences and Bioresources, Perugia Division, Via Madonna Alta, 130 06128, Perugia, Italy. francesco.paolocci@ibbr.cnr.it.
authors.forename: Francesco
authors.identifier: http://orcid.org/0000-0002-9394-876X
authors.initials: F
authors.lastname: Paolocci
mesh_terms: D053898:Biosynthetic Pathways; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D055432:Metabolomics; D009928:Organ Specificity; D010641:Phenotype; D010666:Phenylpropionates / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D044945:Proanthocyanidins / Q000378:metabolism*; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D027843:Vitis / Q000235:genetics*
chemical_list: D010666:Phenylpropionates; D010940:Plant Proteins; D044945:Proanthocyanidins; D014157:Transcription Factors; C013221:proanthocyanidin
keywords: Anthocyanins; Chlorogenic acids; Genetic transformation; Proanthocyanidins; Targeted metabolomics