Amato Alessandra, Cavallini Erika, Zenoni Sara, Finezzo Laura, Begheldo Maura, Ruperti Benedetto, Tornielli Giovanni Battista
Department of Biotechnology, University of Verona Verona, Italy.
Department of Agriculture, Food, Natural Resources, Animals and Environment, University of Padova Padova, Italy.
Front Plant Sci. 2017 Jan 5;7:1979. doi: 10.3389/fpls.2016.01979. eCollection 2016.
A small set of TTG2-like homolog proteins from different species belonging to the WRKY family of transcription factors were shown to share a similar mechanism of action and to control partially conserved biochemical/developmental processes in their native species. In particular, by activating P-ATPases residing on the tonoplast, PH3 from promotes vacuolar acidification in petal epidermal cells whereas TTG2 from enables the accumulation of proanthocyanidins in the seed coat. In this work we functionally characterized identified as the closest grapevine homolog of and . When constitutively expressed in petunia mutant, VvWRKY26 can fulfill the PH3 function in the regulation of vacuolar pH and restores the wild type pigmentation phenotype. By a global correlation analysis of gene expression and by transient over-expression in , we showed transcriptomic relationships of with many genes related to vacuolar acidification and transport in grapevine. Moreover, our results indicate an involvement in flavonoid pathway possibly restricted to the control of proanthocyanidin biosynthesis that is consistent with its expression pattern in grape berry tissues. Overall, the results show that, in addition to regulative mechanisms and biological roles shared with TTG2-like orthologs, VvWRKY26 can play roles in fleshy fruit development that have not been previously reported in studies from dry fruit species. This study paves the way toward the comprehension of the regulatory network controlling vacuolar acidification and flavonoid accumulation mechanisms that contribute to the final berry quality traits in grapevine.
属于WRKY转录因子家族的一小部分来自不同物种的TTG2样同源蛋白，被证明具有相似的作用机制，并在其原生物种中控制部分保守的生化/发育过程。具体而言，来自[具体物种1]的PH3通过激活液泡膜上的P-ATP酶，促进花瓣表皮细胞中的液泡酸化，而来自[具体物种2]的TTG2则使原花青素在种皮中积累。在这项工作中，我们对被鉴定为[具体物种1]和[具体物种2]最接近的葡萄同源物的[目标蛋白名称]进行了功能表征。当在矮牵牛[具体突变体名称]中组成型表达时，VvWRKY26可以在调节液泡pH值方面发挥PH3的功能，并恢复野生型色素沉着表型。通过基因表达的全局相关性分析以及在[具体实验对象]中的瞬时过表达，我们展示了[目标蛋白名称]与葡萄中许多与液泡酸化和转运相关基因的转录组关系。此外，我们的结果表明[目标蛋白名称]参与类黄酮途径，可能仅限于控制原花青素生物合成，这与其在葡萄浆果组织中的表达模式一致。总体而言，结果表明，除了与TTG2样直系同源物共享的调节机制和生物学作用外，VvWRKY26还可以在肉质果实发育中发挥作用，而这些作用在干果物种的研究中尚未报道。这项研究为理解控制液泡酸化和类黄酮积累机制的调控网络铺平了道路，这些机制有助于葡萄最终的浆果品质性状。
