A CEP Peptide Receptor-like Kinase Regulates Auxin Biosynthesis and Ethylene Signaling to Coordinate Root Growth and Symbiotic Nodulation in Medicago truncatula
A CEP Peptide Receptor-like Kinase Regulates Auxin Biosynthesis and Ethylene Signaling to Coordinate Root Growth and Symbiotic Nodulation in Medicago truncatula
复制标题
CEP 肽受体样激酶调节生长素生物合成和乙烯信号传导以协调蒺藜苜蓿根部生长和共生结瘤
DOI：
10.1105/tpc.19.00428
复制
发表时间：
2020
期刊：
影响因子：
11.6
通讯作者：
Tao Wang
中科院分区：
文献类型：
--
作者：
Fugui Zhu;Jie Deng;Hong Chen;Peng Liu;Lihua Zheng;Qinyi Ye;Rui Li;Mathias Brault;Jiangqi Wen;Florian Frugier;Jiangli Dong;Tao Wang
由于共生固氮过程中消耗大量能量，豆科植物必须平衡生长和共生固氮。侧根和根瘤都在根系上形成，在氮素供应减少的条件下，这些器官的发育协调仍然是难以捉摸的。我们发现蒺藜苜蓿紧凑根结构2（MtCRA 2）受体样激酶在促进早期共生体形成和抑制根生长响应低氮是必不可少的。在N饥饿条件下，C-氨基酸编码肽（MtCEP 1）肽可以激活MtCRA 2，导致YUCCA 2（MtYUC 2）生长素生物合成基因表达的抑制，并因此抑制生长素根反应。因此，cra 2的紧密根结构表型可以通过生长素处理或通过过表达MtYUC 2来模拟，相反，用YUC抑制剂处理或MtYUC 2敲除可以挽救cra 2的根表型。MtCEP 1激活的CRA 2还可以与MtEIN 2乙烯信号组分在Ser 643和Ser 924处相互作用并磷酸化，阻止其裂解，从而抑制乙烯反应，从而局部促进根对根瘤菌的易感性。与这种相互作用相一致的是，一个新的2突变挽救了cra 2低表达表型。总体而言，通过减少生长素的生物合成和抑制乙烯信号，MtCEP 1/MtCRA 2途径平衡根和根瘤的发展在低氮条件下。
Because of the large amount of energy consumed during symbiotic nitrogen fixation, legumes must balance growth and symbiotic nodulation. Both lateral roots and nodules form on the root system, and the developmental coordination of these organs under conditions of reduced nitrogen (N) availability remains elusive. We show that theMedicago truncatulaCOMPACT ROOT ARCHITECTURE2 (MtCRA2) receptor-like kinase is essential to promote the initiation of early symbiotic nodulation and to inhibit root growth in response to low N. C-TERMINALLY ENCODED PEPTIDE (MtCEP1) peptides can activate MtCRA2 under N-starvation conditions, leading to a repression ofYUCCA2(MtYUC2) auxin biosynthesis gene expression, and therefore of auxin root responses. Accordingly, the compact root architecture phenotype ofcra2can be mimicked by an auxin treatment or by overexpressingMtYUC2, and conversely, a treatment with YUC inhibitors or anMtYUC2knockout rescues thecra2root phenotype. The MtCEP1-activated CRA2 can additionally interact with and phosphorylate the MtEIN2 ethylene signaling component at Ser643and Ser924, preventing its cleavage and thereby repressing ethylene responses, thus locally promoting the root susceptibility to rhizobia. In agreement with this interaction, thecra2low nodulation phenotype is rescued by anein2mutation. Overall, by reducing auxin biosynthesis and inhibiting ethylene signaling, the MtCEP1/MtCRA2 pathway balances root and nodule development under low-N conditions.