Jeon Jin, Cho Chuloh, Lee Mi Rha, Van Binh Nguyen, Kim Jungmook
Department of Bioenergy Science and Technology, Chonnam National University, Buk-Gu, Gwangju 500-757, Korea.
Department of Bioenergy Science and Technology, Chonnam National University, Buk-Gu, Gwangju 500-757, Korea Kumho Life Science Laboratory, Chonnam National University, Buk-Gu, Gwangju 500-757, Korea
Plant Cell. 2016 Aug;28(8):1828-43. doi: 10.1105/tpc.15.00909. Epub 2016 Jul 18.
Lateral roots (LRs) are a major determinant of the root system architecture in plants, and developmental plasticity of LR formation is critical for the survival of plants in changing environmental conditions. In Arabidopsis thaliana, genetic pathways have been identified that regulate LR branching in response to numerous environmental cues, including some nutrients, salt, and gravity. However, it is not known how genetic components are involved in the LR adaptation response to cold. Here, we demonstrate that CYTOKININ RESPONSE FACTOR2 (CRF2) and CRF3, encoding APETALA2 transcription factors, play an important role in regulating Arabidopsis LR initiation under cold stress. Analysis of LR developmental kinetics demonstrated that both CRF2 and CRF3 regulate LR initiation. crf2 and crf3 single mutants exhibited decreased LR initiation under cold stress compared with the wild type, and the crf2 crf3 double mutants showed additively decreased LR densities compared with the single mutants. Conversely, CRF2 or CRF3 overexpression caused increased LR densities. CRF2 was induced by cold via a subset of the cytokinin two-component signaling (TCS) pathway, whereas CRF3 was upregulated by cold via TCS-independent pathways. Our results suggest that CRF2 and CRF3 respond to cold via TCS-dependent and TCS-independent pathways and control LR initiation and development, contributing to LR adaptation to cold stress.
侧根是植物根系结构的主要决定因素,侧根形成的发育可塑性对于植物在不断变化的环境条件下生存至关重要。在拟南芥中,已鉴定出一些遗传途径,这些途径可响应包括某些养分、盐分和重力在内的多种环境信号来调节侧根分支。然而,尚不清楚遗传成分如何参与侧根对寒冷的适应性反应。在此,我们证明,编码APETALA2转录因子的细胞分裂素响应因子2(CRF2)和CRF3在冷胁迫下调节拟南芥侧根起始过程中发挥重要作用。侧根发育动力学分析表明,CRF2和CRF3均调节侧根起始。与野生型相比,crf2和crf3单突变体在冷胁迫下侧根起始减少,并且与单突变体相比,crf2 crf3双突变体的侧根密度呈累加性降低。相反,CRF2或CRF3过表达导致侧根密度增加。CRF2通过细胞分裂素双组分信号转导(TCS)途径的一个子集被寒冷诱导,而CRF3通过不依赖TCS的途径被寒冷上调。我们的结果表明,CRF2和CRF3通过依赖TCS和不依赖TCS的途径对寒冷作出反应,并控制侧根的起始和发育,有助于侧根适应冷胁迫。