ABSTRACT: Functional characterization of a WRKY transcription factor involved in the regulation of vacuolar transport and flavonoid biosynthesis in grapevine
Project description:Functional characterization of a WRKY transcription factor involved in the regulation of vacuolar transport and flavonoid biosynthesis
Project description:Functional characterization of a WRKY transcription factor involved in the regulation of vacuolar transport and flavonoid biosynthesis in petunia
Project description:The WRKY family represents a plant-specific class of zinc-finger transcription factors (TF) well known for regulating abiotic and biotic stress tolerance and also for their emergent role in the control of various developmental and physiological processes (Rushton et al. 2010, Schluttenhofer et al. 2015). The well-characterized AtTTG2, PhPH3 and BnTTG2 are ortholog WRKY proteins with interchangeable functions ascribed to an emergent clade whose regulatory functions are mainly associated with vacuolar metabolism (Li et al. 2015, Verweij et al. 2016, Gonzalez et al. 2016). In particular, PH3 of Petunia hybrida and TTG2 of Arabidopsis thaliana both act in the control of vacuolar pH and trafficking influencing the deposition of secondary metabolites in the petal epidermal cells and in the seed coat, respectively (Verweij et al. 2016, Gonzalez et al. 2016). In this study we functional characterized VvWRKY26 identified as the closest grapevine homolog of PhPH3 and AtTTG2 (Wang et al. 2014; Verweij et al. 2016). VvWRKY26 can fulfil the PH3 function in the regulation of vacuolar pH and impact many aspects of transport when constitutively expressed in petunia ph3 mutant. By a global correlation analysis of gene expression and by transient over-expression in Vitis vinifera cv. Sultana, we showed transcriptomic relationships of VvWRKY26 with many genes related to acidification and trafficking in grapevine. Moreover, our results indicate an involvement in flavonoid pathway mainly in the control in PA biosynthesis in grapevine that is supported by its expression profile. Overall, with the identification of VvWRKY26 our studies might pave the way towards the comprehension of regulatory mechanism underlying the acidification that contributes to the final berry quality traits.
Project description:The WRKY family represents a plant-specific class of zinc-finger transcription factors (TF) well known for regulating abiotic and biotic stress tolerance and also for their emergent role in the control of various developmental and physiological processes (Rushton et al. 2010, Schluttenhofer et al. 2015). The well-characterized AtTTG2, PhPH3 and BnTTG2 are ortholog WRKY proteins with interchangeable functions ascribed to an emergent clade whose regulatory functions are mainly associated with vacuolar metabolism (Li et al. 2015, Verweij et al. 2016, Gonzalez et al. 2016). In particular, PH3 of Petunia hybrida and TTG2 of Arabidopsis thaliana both act in the control of vacuolar pH and trafficking influencing the deposition of secondary metabolites in the petal epidermal cells and in the seed coat, respectively (Verweij et al. 2016, Gonzalez et al. 2016). In this study we functional characterized VvWRKY26 identified as the closest grapevine homolog of PhPH3 and AtTTG2 (Wang et al. 2014; Verweij et al. 2016). VvWRKY26 can fulfil the PH3 function in the regulation of vacuolar pH and impact many aspects of transport when constitutively expressed in petunia ph3 mutant. By a global correlation analysis of gene expression and by transient over-expression in Vitis vinifera cv. Sultana, we showed transcriptomic relationships of VvWRKY26 with many genes related to acidification and trafficking in grapevine. Moreover, our results indicate an involvement in flavonoid pathway mainly in the control in PA biosynthesis in grapevine that is supported by its expression profile. Overall, with the identification of VvWRKY26 our studies might pave the way towards the comprehension of regulatory mechanism underlying the acidification that contributes to the final berry quality traits.
Project description:itis vinifera cv. Tannat is largely cultivated in Uruguay for the production of high quality red wines. Its most notable characteristic is an elevated content of polyphenolic compounds, which provide an intense purple color and remarkable antioxidant properties to the wine. To characterize the genetic components encoding this important phenotypic characteristic, the genome of the Uruguayan Tannat clone UY11 was sequenced to 134X coverage using the Illumina technology and assembled with a mixed approach of de novo assembly and iterative mapping on the PN40024 reference genome. An approach based on both reference-guided annotation and de novo transcript assembly of RNA-Seq data allowed the definition of 3,673 genes not previously annotated in PN40024 that we consider novel, and the discovery of 2,228 genes not shared with the grapevine reference genome that we consider private to Tannat. Expression analysis showed that private genes contributed substantially (more than 50%) to the overall expression of enzymes involved in phenol and polyphenol biosynthesis indicating that the dispensable portion of the grapevine genome contains many private genes which are likely to contribute to the peculiar phenotypic characteristics of this grapevine variety.
Project description:WRKY genes are transcription factors involved in plant response to pathogen attacks in many plant species. These proteins have been shown to activate expression of defence genes in a salicylic acid- and/or jasmonic acid-dependent signalling pathway. To understand the molecular mechanisms involved in grapevine defence, we previously identified a WRKY gene, VvWRKY1, which was able to enhance tolerance to fungal pathogens when overexpressed in tobacco. To elucidate its role in grapevine, we generated transgenic grapevines that overexpress VvWRKY1. Microarray analyses were performed to compare global gene expression in leaves of the transgenic and wild-type lines. Results showed that expression of genes encoding defence-related proteins was enhanced in the transgenic 35S::VvWRKY1 line. Quantitative RT-PCR analysis confirmed that three genes putatively involved in jasmonic acid signalling pathway, two genes encoding JASMONATE ZIM-domain (JAZ) proteins and one lipoxygenase, are over-expressed. The ability of VvWRKY1 to trans-activate their corresponding promoters was confirmed by transient expression assay in grape protoplasts. After challenging with the downy mildew pathogen Plasmopara viticola, resistance was enhanced in the transgenic line compared to the wild-type line. These results suggest that VvWRKY1 transcription factor is able to control plant disease resistance to one of the main grapevine pathogen by activating jasmonic acid signalling pathway in grapevine.
Project description:Plants regenerated from tissue culture frequently show somaclonal variation. In this study we compared the transcriptomic and epigenetic state of embryogenic callus of grapevine with leaves from mature grapevine plants. In particular, we focussed on the expression of transposable elements and changes in siRNA abundance and genome-wide methylation in these tissues.