北京大学定量生物学中心
学术报告
题 目: Novel auxin signaling transduction mechanism in plants
报告人: Dr. Tongda Xu
Professor, AFU-UCR joint center, Horticulture and Metabolic Biology Center, Fujian Agriculture and Forestry University, Fuzhou, China, 350007
时 间: 12月30日（周一）13:00-14:00
地 点: 北京大学吕志和楼B101报告厅
主持人: 白书农 教授
摘 要:
Auxin, as a key hormone in plant, plays crucial roles essentially in all aspects of plant growth and development. The morphogen-like auxin action, which transduces different auxin concentrations to distinct developmental outputs, may explain this remarkable functional diversity, but the underlying mechanism is poorly understood. Recently, we identified a novel auxin signaling mechanism that, in parallel to the TIR1/AFB receptor-based canonical auxin pathway, interpret auxin gradient to determine differential growth in Arabidopsis. In apical hook development, auxin maximum at the concave side of the apical hook triggered the cleavage and cytosolic/nucleus translocation of the Transmembrane Kinase 1 (TMK1) intracellular domain. Auxin then stabilized two non-canonical Aux/IAAs transcriptional repressors, IAA32 and IAA34 through TMK1-based mechanism, which was distinct from the TIR1/AFB-dependent degradation of canonical Aux/IAAs, that further negatively regulated gene transcription and cell elongation. Recently, we found that the TMK1 protein cleavage was regulated by the auxin-promoted quick phosphorylation adjacent to the cleavage site, which was also controlled by PP2A phosphatase. These phosphorylation sites functioned as the molecular switch of the TMK1-cleavage based pathways. All above findings illustrated a novel cell surface-originating auxin signaling in regulating differential growth in plants. Parallel action of TMK1 and TIR1/AFB mechanisms converging on the partially overlapped transcriptional regulators allows distinct interpretation of differential cellular auxin concentrations thus enabling complex developmental outputs of this versatile signaling molecule.
报告人简介：
徐通达，2003年7月毕业于北京大学生物科学本科专业，2010年12月毕业于美国加州大学细胞分子发育生物学专业，现任福建农林大学海峡联合研究院园艺中心副主任、教授。主要从事研究植物激素信号传导途径调控植物生长发育的分子机制。从事科研工作以来发表研究论文及综述 19篇，其中第一作者及通讯作者文章11篇。其代表性研究成果发表在 Nature, Cell, Science, PNAS，Plos Biology 等国际知名期刊上。其中2019年以独立通讯作者发表Nature文章，揭示了全新信号通路调控生长素局部浓度效应的分子机制。2014 年，入选国家自然基金委优秀青年基金项目；2014 年至今担任中国植物生理和分子生物学学会理事，2019 年至今担任该学会常务理事；2017 年入选福建省闽江学者特聘教授。详情请见http://net.fafu.edu.cn/hist/6a/fd/c6023a223997/page.htm
