Legume-specific SnRK1 promotes malate supply to bacteroids for symbiotic nitrogen fixation  

作　　者：Da Guo Peng Liu Qianwen Liu Lihua Zheng Sikai Liu Chen Shen Li Liu Shasha Fan Nan Li Jiangli Dong Tao Wang 

机构地区：[1]College of Biological Sciences,China Agricultural University,Bejing 100193,China

出　　处：《Molecular Plant》2023年第9期1396-1412,共17页分子植物（英文版）

基　　金：the National Key Research Development Program of China(2022YFA0912100);the National Natural Science Foundation of China(NFSC;32070272);the major demonstration project"The Open Competition"for seed industry science and technology innovation in Inner Mongolia(2022JBGS0016).

摘　　要：Nodulation is an energy-expensive behavior driven by legumes by providing carbon sources to bacteroids and obtaining nitrogen sources in return.The energy sensor sucrose nonfermenting 1-related protein kinase 1(SnRK1)is the hub of energy regulation in eukaryotes.However,the molecular mechanism by which SnRK1 coordinates the allocation of energy and substances during symbiotic nitrogen fixation(SNF)remains unknown.In this study,we identified the novel legume-specific SnRK1α4,a member of the SnRK1 family that positively regulates SNF.Phenotypic analysis showed that nodule size and nitrogenase activity increased in SnRK1α4-overexpressing plants and decreased significantly in snrk1α4 mutants.We demonstrated that a key upstream kinase involved in nodulation,Does Not Make Infection 2(DMI2),can phosphorylate SnRK1α4 at Thr175 to cause its activation.Further evidence clarified that SnRK1α4 phosphorylates the malate dehydrogenases MDH1/2 to promote malate production in the cytoplasm,supplying carbon sources to bacteroids.Therefore,our findings reveal an essential role of the DMI2–SnRK1α4–MDH pathway in supplying carbon sources to bacteroids for SNF and provide a new module for constructing cereal crops with SNF.

关 键 词：energy sensor SnRK1α4 PHOSPHORYLATION malate anabolism NODULATION Medicago truncatula 

分 类 号：G63[文化科学—教育学]