An Uncanonical CCCH-Tandem Zinc-Finger Protein Represses Secondary Wall Synthesis and Controls Mechanical Strength in Rice.
An Uncanonical CCCH-Tandem Zinc-Finger Protein Represses Secondary Wall Synthesis and Controls Mechanical Strength in Rice.
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DOI：
10.1016/j.molp.2017.11.004
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发表时间：
2018-01
期刊：
影响因子：
27.5
通讯作者：
Dongmei Zhang;Zuopeng Xu;Shaoxue Cao;Kunling Chen;Shance Li;Xiangling Liu;Caixia Gao;Baocai Zhang;Yihua Zhou
中科院分区：
文献类型：
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作者：
Dongmei Zhang;Zuopeng Xu;Shaoxue Cao;Kunling Chen;Shance Li;Xiangling Liu;Caixia Gao;Baocai Zhang;Yihua Zhou
次生壁是生物质的主要组成部分，对植物的生长和环境适应有很大的影响。次生壁的合成是由一个复杂的信号转导网络进行转换和调节的。然而，对这些调控途径的理解有限。在这里，我们报告，ILA 1相互作用蛋白4（IIP 4）可以抑制次生壁的合成。IIP 4是Raf-like MAPKKK的磷酸化底物，但其功能尚不清楚。通过产生IIP 4突变体和相应的转基因植株，我们发现IIP 4的损伤促进次生壁的形成。基因表达和反式激活活性分析表明，IIP 4负调控MYB 61和CESA的表达，但不结合其启动子。IIP 4与次生壁合成的上游调控因子NAC 29/NAC 31相互作用，抑制植物次生壁合成的下游调控途径。突变分析表明，拟磷酸化IIP 4蛋白从细胞核易位到细胞质，释放相互作用的NAC并减弱其抑制功能。此外，我们发现，IIPs是进化保守的，并共享未报告的CCCH基序，称为非经典CCCH串联锌指蛋白。总的来说，我们的研究为控制次生壁合成提供了机理上的见解，并为改善作物的相关农艺性状提供了机会。
Secondary walls, which represent the bulk of biomass, have a large impact on plant growth and adaptation to environments. Secondary wall synthesis is switched and regulated by a sophisticated signaling transduction network. However, there is limited understanding of these regulatory pathways. Here, we report that ILA1-interacting protein 4 (IIP4) can repress secondary wall synthesis. IIP4 is a phosphorylation substrate of an Raf-like MAPKKK, but its function is unknown. By generatingiip4mutants and relevant transgenic plants, we found that lesions inIIP4enhance secondary wall formation. Gene expression and transactivation activity assays revealed that IIP4 negatively regulates the expression ofMYB61andCESAs but does not bind their promoters. IIP4 interacts with NAC29/NAC31, the upstream regulators of secondary wall synthesis, and suppresses the downstream regulatory pathways in plants. Mutagenesis analyses showed that phosphomimic IIP4 proteins translocate from the nucleus to the cytoplasm, which releases interacting NACs and attenuates its repression function. Moreover, we revealed that IIPs are evolutionarily conserved and share unreported CCCH motifs, referred to as uncanonical CCCH-tandem zinc-finger proteins. Collectively, our study provides mechanistic insights into the control of secondary wall synthesis and presents an opportunity for improving relevant agronomic traits in crops.