Cytokinin signaling promotes salt tolerance by modulating shoot chloride exclusion in maize  

作　　者：Pan Yin Xiaoyan Liang Hanshu Zhao Zhipeng Xu Limei Chen Xiaohong Yang Feng Qin Jingbo Zhang Caifu Jiang 

机构地区：[1]State Key Laboratory of Plant Environmental Resilience,College of Biological Sciences,China Agricultural University,Bejing 100094,China [2]State Key Laboratory of Nutrient Use and Management,College of Resources and Environmental Sciences,National Academy of Agriculture Green Development,ChinaAgriculturalUniversity,Beijing100193,China [3]Center for Crop Functional Genomics and Molecular Breeding,China Agricultural University,Bejing 100094,China [4]Laboratory of Agrobiotechnology and National Maize Improvement Center of China,Department of Plant Genetics and Breeding,China Agricultural University,Beijing100193,China [5]Outstanding Discipline Program for the Universities in Bejing,Beijing 100094,China

出　　处：《Molecular Plant》2023年第6期1031-1047,共17页分子植物（英文版）

基　　金：the financial support from National Key Research and Development Program of China(2022YFA1300061 to C.J.,2022YFD1900704 and 2021YFF1000500 to J.Z.);Beijing Outstanding Young Scientist Program(BJJWZYJH01201910019026 to F.Q.);National Natural Science Foundation of China(32070306 to J.Z.);the Chinese Universities Scientific Fund(15051011 to C.J.,2022RC046 to J.Z.);the 2115 Talent Development Program of China Agricultural University.

摘　　要：Excessive accumulation of chloride(Cl^(-))in the aboveground tissues under saline conditions is harmful to crops.Increasing the exclusion of Cl^(-) from shoots promotes salt tolerance in various crops.However,the underlying molecular mechanisms remain largely unknown.In this study,we demonstrated that a type A response regulator(ZmRR1)modulates Cl^(-) exclusion from shoots and underlies natural variation of salt tolerance in maize.ZmRR1 negatively regulates cytokinin signaling and salt tolerance,likely by interacting with and inhibiting His phosphotransfer(HP)proteins that are key mediators of cytokinin signaling.A naturally occurring non-synonymous SNP variant enhances the interaction between ZmRR1 and ZmHP2,conferring maize plants with a salt-hypersensitive phenotype.We found that ZmRR1 undergoes degradation under saline conditions,leading to the release of ZmHP2 from ZmRR1 inhibition,and subsequently ZmHP2-mediated signaling improves salt tolerance primarily by promoting Cl^(-) exclusion from shoots.Furthermore,we showed that ZmMATE29 is transcriptionally upregulated by ZmHP2-mediated signaling under highly saline conditions and encodes a tonoplast-located Cl^(-) transporter that promotes Cl^(-) exclusion from shoots by compartmentalizing Cl^(-) into the vacuoles of root cortex cells.Collectively,our study provides an important mechanistic understanding of the cytokinin signaling-mediated promotion of Cl^(-) exclusion from shoots and salt tolerance and suggests that genetic modification to promote Cl^(-) exclusion from shoots is a promising route for developing salt-tolerant maize.

关 键 词：cytokinin signaling salt tolerance high-Cl^(-)tolerance Cl^(-)transporter MAIZE 

分 类 号：Q94[生物学—植物学]