The TATA-box binding protein-associated factor TAF12b facilitates the degradation of type B response regulators to negatively regulate cytokinin signaling  

作　　者：Liu-Ming Guo Jing Li Pan-Pan Qi Jie-Bing Wang Hussein Ghanem Ling Qing Heng-Mu Zhang 

机构地区：[1]Chongqing Key Laboratory of Plant Disease Biology,College of Plant Protection,Southwest University,Chongqing 400716,China [2]Laboratory of Virology,Innovation Center of Chinese Medicine Crops,Institute of Virology and Biotechnology,Zhejiang Academy of Agricultural Sciences,Hangzhou 310021,China [3]College of Life Sciences,China Jiliang University,Hangzhou 310018,China [4]Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River(Ministry of Education),Southwest University,Chongqing 400716,China [5]National Citrus Engineering Research Center,Southwest University,Chongqing 400712,China

出　　处：《Plant Communications》2024年第12期142-160,共19页植物通讯(英文)

基　　金：Natural Science Foundation of China(U20A2037,31972980,and 32272482);Talent Project of Zhejiang Province(2019R52033);Key Research and Development Program of Zhejiang Province(2019C02018);Innovation Research 2035 Pilot Plan of Southwest University(SWU-XDZD22002),China.

摘　　要：Cytokinins(CKs)are one of the important classes of plant hormones essential for plant growth and devel-opment.TATA-box binding protein-associated factor 12b(TAF12b)is involved in CK signaling,but its molecular and biochemical mechanisms are not fully understood.In this study,TAF12b of Nicotiana ben-thamiana(NbTAF12b)was found to mediate the CK response by directly interacting with type B response regulators(B-RRs),positive regulators of CK signaling,and inhibiting their transcriptional activities.As a transcriptional co-factor,TAF12b specifically facilitated the proteasomal degradation of non-phosphorylated B-RRs by recruiting the KISS ME DEADLY family of F-box proteins.Such interactions between TAF12b and B-RRs also occur in other plant species.Genetic transformation experiments showed that overexpression of NbTAF12b attenuates the CK-hypersensitive phenotype conferred by NbRR1 over-expression.Taken together,these results suggest a conserved mechanism in which TAF12b negatively regulates CK responses by promoting 26S proteasome-mediated B-RR degradation in multiple plant spe-cies,providing novel insights into the regulatory network of CK signaling in plants.

关 键 词：TATA-box binding protein-associated factor 12b TBP TAF12b cytokinin signaling CK signaling type B response regulators B-RRs proteasomal degradation 

分 类 号：Q94[生物学—植物学]