转录调控因子FLPMYB88和生长素在气孔发育中的功能和互作

Transcription factor FLP and MYB88 control the development and patterning of stoma in the epidermis of Arabidopsis. Double mutant of flpmyb88 has clustered stoma in the epidermis.Our privous research showed that FLP/MYB88 may also affect auxin polar transportation and level in stomatal lineage cells by targeting GNOM and PINs besides its directly regulation of cell cycle genes.And the feedback pathway of auxin on FLP may exist as well. FLP is therefore likely to be a major and coordinated regulator of auxin level/signal as well as of division to provide the appropriate number of cells in the correct positions. But little is known about how FLP/MYB88 regulate the expression of GNOM and PINs gene and control the local auxin level/signal in the stomatal lineage cells to affect their division, diffentiation and mutuartion. Cell biological，genetical and biochemistry technologies will be used to determine their relationship and function in stomata development. Levels of expression of target genes in WT and mutants by RT-QPCR will be used to determined whether flp induces abnormal GNOM and PIN3 levels in specific cells. Triple mutant of flpmyb88gnom will be generated by amiRNA and intergressing crossing to confirm that GNOM are downstream genetically of FLP/MYB88. Auxin related marker gene and chemical treatment combined with time lapse will be used to analyse how clusters form in the mutant and the auxin level dynamic change in this background.This project will focus on stomatal development as to whether and how FLPMYB88 integrates local auxin levels via GNOM and PIN3 action in cell division, differentiation and muturation of precursor cells.

转录调控因子FLP/MYB88控制拟南芥表皮气孔发育和分布，其双突变体具有丛生密集的气孔表型。我们前期研究表明，FLP/MYB88不仅直接调节细胞分裂周期基因表达，还通过与GNOM和PINs蛋白的相互作用，控制气孔发育世系细胞中生长素极性运输和胞内浓度，生长素对FLPMYB88功能也有反馈调节。FLP/MYB88很可能通过协调细胞分裂与生长素s水平/信号，以维持正常部位特定细胞的正常分裂，形成分散和适当数量的气孔。本项目拟利用细胞生物学、遗传学和生物化学的方法，通过RT-QPCR分析基因表达,amiRNA技术和杂交获得多突变体，应用生长素信号相关荧光蛋白标记基因，结合Time lapse显微摄像技术等，集中研究FLP/MYB88如何调节GNOM和PINs表达，调控前体细胞生长素水平/信号，并与细胞分裂过程相协调，控制前体细胞的分裂、分化和成熟，调控气孔发育。

生长素调节植物生长发育，包括表皮气孔的形成和分布。而转录因子FLPMYB88参与调节气孔世系中保卫母细胞（GMC）细胞的均等分裂过程。但生长素如何参与调节气孔发育的多个细胞学过程，及自身又如何受到其他因素的调节，目前还不清楚。本项目采用细胞生物学、遗传学和生物化学的方法，通过 RT-QPCR 分析基因表达, amiRNA 技术和杂交获得多突变体，应用生长素信号相关荧光蛋白标记基因，结合Time lapse 显微摄像技术，分析了生长素转运及核信号途径在气孔发育中的动态，明确生长素在气孔发育不同阶段发挥不同的功能。在气孔发育早期阶段，世系前体细胞增殖过程中，高浓度的生长素及其下游转录活性对于不等分裂的发生非常重要，而生长素转运，尤其是胞内定位依赖于GNOM的PIN蛋白介导的生长素外运，在气孔前体细胞退出增值，进入终端分裂和分化这一重要的发育转换过程中的作用。同时，证实FLP/MYB88通过直接靶向并抑制GNOM基因的表达，而影响PINs介导的生长素外运过程，进而调节气孔世系前体细胞从早期增殖想后期分化的发育转换。GNOM基因位于FLPMYB88基因的遗传学下游，gnom突变能部分地回复flpmyb88因GMC过多分裂而导致的多细胞气孔簇表型。本项目揭示了生长素在气孔发育的不同细胞学过程中的不同作用，及转录因子FLPMYB88通过调节生长素转运而介导气孔发育过程中发育命运的转换机制，揭示了FLPMYB88在调节气孔发育中除了直接调节细胞分裂之外的新功能，推进了生长素调节气孔发育分子机理的认识，为利用激素调控气孔发育和植株生长及抗逆奠定了理论基础。