NLP1 reciprocally regulates nitrate inhibition of nodulation through SUNN-CRA2 signaling in Medicago truncatula  

作　　者：Zhenpeng Luo Jie-shun Lin Yali Zhu Mengdi Fu Xiaolin Li Fang Xie 

机构地区：[1]National Key Laboratory of Plant Molecular Genetics,CAS Center for Excellence in Molecular Plant Sciences,Shanghai Institute of Plant Physiology and Ecology,Chinese Academy of Sciences,Shanghai 200032,China [2]University of the Chinese Academy of Sciences,Beijing,China [3]Department of Molecular Biology and Genetics,Aarhus University,DK-8000 Aarhus,Denmark

出　　处：《Plant Communications》2021年第3期117-129,共13页植物通讯（英文）

基　　金：supported by grants from The National Key Research&Development Program of China(2016YFA0500500 and 2016YFD0100702);the NSFC(31670242)to F.X.

摘　　要：Most legume plants can associate with diazotrophic soil bacteria called rhizobia,resulting in new root organs called nodules that enable N2 fixation.Nodulation is an energy-consuming process,and nodule number is tightly regulated by independent systemic signaling pathways controlled by CLE/SUNN and CEP/CRA2.Moreover,nitrate inhibits legume nodulation via local and systemic regulatory pathways.In Medicago truncatula,NLP1 plays important roles in nitrate-induced inhibition of nodulation,but the relationship between systemic and local pathways in mediating nodulation inhibition by nitrate is poorly understood.In this study,we found that nitrate induces CLE35 expression in an NLP1-dependent manner and that NLP1 binds directly to the CLE35 promoter to activate its expression.Grafting experiments revealed that the systemic control of nodule number involves negative regulation by SUNN and positive regulation by CRA2 in the shoot,and that NLP1’s control of the inhibition of rhizobial infection,nodule development,and nitrogenase activity in response to nitrate is determined by the root.Unexpectedly,grafting experiments showed that loss of CRA2 in the root increases nodule number at inhibitory nitrate levels,probably because of CEP1/2 upregulation in the cra2 mutants,suggesting that CRA2 exerts active negative feedback regulation in the root.

关 键 词：CRA2 CEP CLE nitrate inhibition of nodulation NLP1 SUNN 

分 类 号：Q94[生物学—植物学]