The VviNAC33 acts a molecular switch by activating leaf degreening and repressing vegetative growth during the immature-to-mature phase transition in grapevine

In this study we functionally characterized the grapevine VviNAC33 by its transient and stable overexpression in grapevine homologous system and the creation of its chimeric repressor. Through the application of DAP-seq approach we identified putative direct targets of VviNAC33, among which the SGR1 involved in the breakdown of chlorophyll. Stable VviNAC33 overexpressing transgenic plants displayed an obvious degreening effect on leaves and an inhibition of leaf growth. Consistently, transgenic plant expressing a chimeric repressor of the VviNAC33 showed the opposite phenotypic alterations. Our results evidenced that VviNAC33 is a direct player of leaf senescence program and propose a blueprint of the complex transcriptional regulatory network that govern organ phase transition in grapevine. transcription factor VviNAC33 is directly involved in leaf degreening and organ growth. Overall design: Through the application of DAP-seq approach we identified putative direct targets of VviNAC33.

本研究通过在葡萄同源表达系统中开展瞬时过表达与稳定过表达实验，并构建VviNAC33的嵌合抑制子，对葡萄VviNAC33进行了功能表征。借助DNA亲和纯化测序（DAP-seq）技术，我们鉴定得到VviNAC33的潜在直接靶基因，其中包含参与叶绿素降解的滞绿基因1（SGR1）。稳定过表达VviNAC33的转基因植株叶片呈现出明显的褪绿表型，且叶片生长受到抑制。与之相符的是，表达VviNAC33嵌合抑制子的转基因植株则表现出完全相反的表型改变。本研究结果证实VviNAC33是叶片衰老程序的直接调控因子，并为解析葡萄器官阶段转变的复杂转录调控网络提供了研究框架。转录因子VviNAC33直接参与叶片褪绿与器官生长调控。总体实验设计：通过DNA亲和纯化测序（DAP-seq）技术，我们鉴定得到VviNAC33的潜在直接靶基因。