BioProject

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. More...

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. Overall design: For transient transformation of Vitis vinifera cv. Sultana, the 35S:VvWRKY26 construct was transferred to Agrobacterium tumefaciens strain C58C1 by electroporation. As control, Agrobacterium was also transformed with a pK7WG2.0 vector containing a non-coding sequence. Six in vitro five weeks old plants of grapevine cv. Sultana were immersed in each bacterial suspension and vacuum infiltrated (2 X 2 min at 90kPa). After agroinfiltration, plantlets were rinsed with sterile water and allowed to recover in vitro for six days before collecting material for RNA extraction and transcriptomic analysis Less...