ARF2 coordinates with PLETHORAs and PINs to orchestrate ABA-mediated root meristem activity in Arabidopsis
ARF2 coordinates with PLETHORAs and PINs to orchestrate ABA-mediated root meristem activity in Arabidopsis
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DOI：
10.1111/jipb.12506
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发表时间：
2017-01-01
影响因子：
11.4
通讯作者：
Gong, Zhizhong
中科院分区：
文献类型：
--
作者：
Promchuea, Sujittra;Zhu, Yujuan;Gong, Zhizhong
多种激素，包括脱落酸（ABA）和生长素，调节拟南芥根分生组织的细胞分裂和分化。生长素响应因子 2 (ARF2) 作为 ABA 响应的负调节因子，因为 art2 突变体的种子萌发和初生根生长对 ABA 高度敏感。在这项研究中，我们发现ABA处理降低了arf2-101突变体根分生组织中PIN-FORMEDs (PIN)生长素外排载体PIN1、PIN3、PIN4和PIN7的表达水平，其程度比野生型更大。此外，arf2-101 pin1 和 arf2-101 pin4 双突变体表现出比 arf2-101 突变体更少的 ABA 诱导的根分生组织活性抑制。此外，ARF2 正介导转录因子 PLETHORA 1 (PLT1) 基因的转录，但在根分生组织的蛋白质水平上负介导 PLT2。使用地塞米松（DEX）诱导的转基因系Pro35S：PLT2-GR，我们发现一旦PLT2被DEX诱导，PLT2就会极大地促进细胞分裂，并完全抑制arf2-101突变体根分生组织的细胞分化，这可以通过ABA处理部分逆转，表明ABA在ARF2依赖和独立途径中调节根分生组织活性。我们的结果揭示了一个复杂的调控架构，其中 ARF2 与 PLT 和 PIN 协调，协调 ABA 介导的拟南芥根分生组织活性调控。
Multiple hormones, including abscisic acid (ABA) and auxin, regulate cell division and differentiation of Arabidopsis root meristems. AUXIN RESPONSE FACTOR 2 (ARF2) functions as a negative regulator of ABA responses, as seed germination and primary root growth of arf2 mutants are hypersensitive to ABA. In this study, we found that ABA treatment reduced the expression levels of the PIN-FORMEDs (PIN) auxin efflux carriers, PIN1, PIN3, PIN4, and PIN7, to a greater extent in the root meristems of arf2-101 mutant than in the wild type. Also, arf2-101 pin1 and arf2-101 pin4 double mutants show less ABA-induced inhibition of root meristem activity than the arf2-101 mutants. Furthermore, ARF2 positively mediates the transcripts of transcription factor PLETHORA 1 (PLT1) gene but negatively mediates PLT2 at protein level in root meristems. Using a dexamethasone (DEX)-inducible transgenic line, Pro35S:PLT2-GR, we showed that PLT2 greatly promotes cell division and completely inhibits cell differentiation in root meristems of the arf2-101 mutant once PLT2 is induced by DEX, which can be partially reversed by ABA treatment, suggesting that ABA regulates root meristem activity in both ARF2-dependent and independent pathways. Our results uncover a complex regulatory architecture in which ARF2 coordinates with PLTs and PINs to orchestrate ABA-mediated regulation of root meristem activity in Arabidopsis.