褪黑素和细胞分裂素互作调控拟南芥主根生长的机理研究

发布时间：2018-03-05 16:15

本文选题：褪黑素　切入点：细胞分裂素　出处：《中国科学院武汉植物园》2017年硕士论文　论文类型：学位论文

【摘要】：植物激素之间有广泛而复杂的相互作用。细胞分裂素和生长素共同参与调控拟南芥主根分生组织的分裂和分化影响主根的生长。在植物中,褪黑素作为抗氧化剂和生长调节子被广泛研究。相关的研究表明,褪黑素以类似于生长素IAA的方式调节植物的根系,然而,一些研究则认为褪黑素在根的生长过程中的作用与生长素无关。最近的一项研究表明,外源高浓度的褪黑素通过抑制生长素合成和极性运输抑制根分生组织,但是到目前为止,关于低浓度褪黑素在主根生长过程中作用机理的研究还未见报道。在本研究中,我们分别以野生型拟南芥(Col-0)和细胞分裂素合成酶诱导超表达转基因植株(IPT8-OX)为材料,外源添加褪黑素和细胞分裂素、诱导剂雌二醇(estradiol)和生长素极性运输抑制剂TIBA后,通过表型分析、相关基因表达量、蛋白定量等多方面的研究,探讨褪黑素和细胞分裂素对主根生长的调控机理。主要研究结果如下:(1)低浓度的褪黑素(100 nM)对主根生长起正调控效应,通过促进根尖分生区细胞数目的增多而促进拟南芥主根生长,拮抗外源添加及内源诱导细胞分裂素对主根生长的抑制作用;(2)褪黑素通过抑制细胞分裂素信号途径关键基因(AHK4、AHP2、AHP3、AHP5、ARR15)的表达以拮抗细胞分裂素对主根生长的调控作用;(3)褪黑素通过调控生长素极性运输载体(PIN1、PIN2、PIN3 AUX1、AXR3)的转录水平使生长素的运输发生改变。除此之外,褪黑素和细胞分裂素在蛋白水平上可影响PIN2和AUX1的积累。(4)添加生长素极性运输抑制剂TIBA的实验,说明褪黑素和细胞分裂素调控主根生长离不开生长素的转运。综上所述,我们的数据表明低浓度褪黑素促进拟南芥主根生长,褪黑素和细胞分裂素在主根生长的调控过程中具有拮抗作用,而生长素的极性运输在这个过程中具有重要的作用。相关研究为进一步揭示褪黑素的生物学功能和激素之间的相互调控提供了直接的证据,对于以后植物主根的研究也具有重要意义。
[Abstract]:Plant hormones have extensive and complex interactions. Cytokinins and auxins are involved in regulating the division and differentiation of the main root meristem of Arabidopsis thaliana. Melatonin is widely studied as an antioxidant and a growth regulator. Studies have shown that melatonin regulates the roots of plants in a manner similar to that of auxin IAA, however, Some studies suggest that the role of melatonin in root growth is unrelated to auxin. A recent study showed that exogenous high concentrations of melatonin inhibit root meristem by inhibiting auxin synthesis and polar transport, but so far, In this study, we used wild type Arabidopsis thaliana Col-0) and cytokinin synthase induced overexpression transgenic plant IPT8-OX as materials. After exogenous addition of melatonin, cytokinin, estradiol (estradiol) and growth hormone polar transport inhibitor (TIBA), phenotypic analysis, gene expression and protein quantification were studied. To study the mechanism of melatonin and cytokinin regulating the growth of main root. The main results are as follows: 1) the low concentration of melatonin 100 nm) has positive effect on the growth of main root. To promote the growth of Arabidopsis by increasing the number of cells in the apical meristem. Antagonistic effects of exogenous and Endogenous cytokinins on the growth of main Roots; melatonin antagonizes the expression of AHK4 (AHP2AHP3AHP5AHP5ARR15) by inhibiting cytokinin signaling pathway in order to antagonize the regulation of cytokinin on the growth of the main root. Melatonin changes the transport of auxin by regulating the transcription level of the polar transport vector PIN1PIN2PIN3AUX1AXR3. Melatonin and cytokinin can affect the accumulation of PIN2 and AUX1 at protein level. 4) the experiment of adding auxin polar transport inhibitor TIBA shows that melatonin and cytokinin can not regulate the growth of main root without auxin transport. Our data show that low concentration of melatonin promotes the growth of Arabidopsis thaliana main root, and melatonin and cytokinin play an antagonistic role in regulating the growth of Arabidopsis thaliana. The polar transport of auxin plays an important role in this process. Related studies provide direct evidence to further reveal the biological functions of melatonin and the regulation of hormones. It is also of great significance for the study of the main roots of plants in the future.
【学位授予单位】：中国科学院武汉植物园
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q945

【参考文献】