PIN4介导的生长素和细胞分裂素互作调控根分生区细胞分裂与分化稳态平衡的机制研究

如何维持及调控细胞分裂和细胞分化的稳态平衡是细胞与发育生物学中的重要科学问题。植物激素生长素和细胞分裂素是根分生区细胞分裂和细胞分化稳态平衡的主要调控者，但两者如何互作从而维持该稳态平衡的机制仍知之甚少。我们发现生长素合成途径关键基因CKRC1和细胞分裂素B型反应调节子ARR1,12在调控拟南芥根分生区生长中存在拮抗作用，并发现ckrc1-1和arr1,12根近端分生区中的DR5rev::GFP荧光强度均显著降低，进一步的研究发现这与生长素极性运输载体相关，ckrc1-1和arr1,12中的PIN4::PIN4:GFP荧光均显著减弱。本项目我们将在此基础上利用分子生物学，生理学等技术展开进一步的实验来探究CKRC1,ARR1/12和PIN4三者之间的信号网络。通过本项目的研究有望为了解生长素和细胞分裂素的互作如何维持细胞分裂和和细胞分化的稳态平衡这一重要科学问题提供一个全新的视角。

Understanding the rules that maintain precise spatiotemporal balance of cell division and cell differentiation is the fundamental challenge in cell and developmental biology. The Arabidopsis root is an ideal organ for studying this problem, the central players which control cell division and cell differentiation in roots are the hormones auxin and cytokinin that auxin regulates cell divisions, and cytokinin triggers the transition to differentiation, however, little is known how the interactions between auxin and cytokinin to maintain and regulate this dynamic balance. Here we found that CKRC1-mediated auxin biosynthesis and ARABIDOPSIS RESPONSE REGULATOR1,12 (ARR1,12)-mediated cytokinin signaling had antagonistic interaction on the control of root meristem size. To research how they antagonize each other, we examined the auxin response in the root meristem of the single, double and triple mutants among ckrc1-1, arr1 and arr12 by analyzing the expression pattern of DR5rev::GFP. The results showed that the fluorescence intensity of DR5rev::GFP decreased significantly in the proximal meristematic region of the roots in both ckrc1-1 and arr1,12. Further study found that this phenomenon was related to auxin polar transporter, that the fluorescence of PIN4::PIN4:GFP in both ckrc1-1 and arr1,12 is decreased significantly. Therefore, we will use the methods of molecular biology, physiology and other experimental techniques to carry out further experiments, in order to understand the signal network among CKRC1,ARR1/12 and PIN4, thus revealing how this signal network achieves the interaction of auxin and cytokinin in maintaining the dynamic balance of cell division and cell differentiation.