PDF(Pubmed)
Abstract：
Roots are the main organ for water uptake and the earliest part of a plant\'s response to drought, making them of great importance to our understanding of the root system\'s response to drought. However, little is known about the underlying molecular mechanisms that control root responses to drought stress. Here, we identified and functionally characterized the AP2/ERF family transcription factor (TF) PtrABR1 and the upstream target gene zinc-finger protein TF PtrYY1, which respond to drought stress by promoting the growth and development of lateral roots in Populus trichocarpa. A root-specific induction of PtrABR1 under drought stress was explored. The overexpression of PtrABR1 (PtrABR1-OE) promoted root growth and development, thereby increasing tolerance to drought stress. In addition, PtrYY1 is directly bound to the promoter of PtrABR1 under drought stress, and the overexpression of PtrYY1 (PtrYY1-OE) promoted lateral root growth and development and increased tolerance to drought stress. An RNA-seq analysis of PtrABR1-OE with wild-type (WT) poplar identified PtrGH3.6 and PtrPP2C44, which share the same pattern of expression changes as PtrABR1. A qRT-PCR and cis-element analysis further suggested that PtrGH3.6 and PtrPP2C44 may act as potential downstream targets of PtrABR1 genes in the root response pathway to drought stress. In conclusion, these results reveal a novel drought regulatory pathway in which PtrABR1 regulates the network through the upstream target gene PtrYY1 and the potential downstream target genes PtrGH3.6 and PtrPP2C44, thereby promoting root growth and development and improving tolerance to drought stress.
摘要：
根是吸收水分的主要器官，也是植物对干旱反应的最早部分，使它们对我们理解根系对干旱的反应非常重要。然而,对控制根系对干旱胁迫反应的潜在分子机制知之甚少。这里,我们鉴定并功能表征了AP2/ERF家族转录因子（TF）PtrABR1和上游靶基因锌指蛋白TFPtrYY1，它们通过促进毛果杨侧根的生长发育来响应干旱胁迫。探索了干旱胁迫下PtrABR1的根特异性诱导。过表达PtrABR1(PtrABR1-OE)促进根系生长发育,从而增加对干旱胁迫的耐受性。此外,PtrYY1在干旱胁迫下直接与PtrABR1的启动子结合，PtrYY1（PtrYY1-OE）的过表达促进了侧根的生长发育，增强了对干旱胁迫的耐受性。PtrABR1-OE与野生型（WT）杨树的RNA-seq分析鉴定了PtrGH3.6和PtrPP2C44，它们与PtrABR1具有相同的表达变化模式。qRT-PCR和顺式元件分析进一步表明，PtrGH3.6和PtrPP2C44可能是根系对干旱胁迫的响应途径中PtrABR1基因的潜在下游靶标。总之,这些结果揭示了一种新的干旱调控途径，其中PtrABR1通过上游靶基因PtrYY1和潜在的下游靶基因PtrGH3和PtrPP2C44调节网络，从而促进根系生长发育并提高对干旱胁迫的耐受性。
