生长素参与杉木维管形成层次生发育相关基因表达分析毕业论文

 2021-04-12 11:04

摘 要

维管形成层分化产生的次生韧皮部和木质部是林木次生维管系统构建和木材形成的重要来源,该次生分生组织的周期性发育活动直接决定着木材的产量和质量。生长素作为植物体重要的生理调节物质,被发现参与对维管形成层细胞分裂和次生木质部分化等次生发育活动的调控过程,尤其是随着生长素在林木维管形成层区域径向浓度梯度的发现,其更被认为是控制维管形成层次生发育的重要位置信号。

本研究以不同浓度外源生长素-羊毛脂混合物(0、1和3mg.iaa/g.lanolin)处理的杉木优良无性系“洋口020”一年生茎杆为材料,通过实时定量PCR(qPCR) 技术,对同源克隆的杉木ClWOX4和ClHB8基因进行了定量和定位表达分析,结果如下:

    1)同源克隆的杉木ClWOX4全长1571bp,ClHB8全长2493bp。通过Blastx软件与genbank同源序列比对及系统进化树分析,发现分别与拟南芥的AtWOX4和AtHB8具有高度的同源性(e-valuelt;10-4);

2)组织特异性表达分析,发现ClWOX4在杉木的次生韧皮部、维管形成层区域以及次生木质部中呈现较为均一性的表达,而ClHB8则主要集中于次生维管发育的近轴区域表达;

3)在不同浓度外源IAA处理的杉木阶段发育材料中,相对于正常表达水平,ClWOX4在0mg.iaa/g.lanolin处理的材料中呈现持续的上调表达,而在1mg.iaa/g.lanolin处理材料中则呈现较为稳定的表达区域,只是在处理的中、前期相对正常水平表现下调,在后期则表现为一定水平的上调表达趋势;3mg.iaa/g.lanolin处理对ClWOX4基因表达的调控与正常生长材料相似,均呈现逐渐下调的表达区域,只是相对正常水平表现明显的上调。

ClHB8基因在不同浓度外源IAA处理材料中的表达趋势与正常生长的杉木表达相一致,即呈现由高到低的表达趋势,其中在0和1mg.iaa/g.lanolin处理材料中的表达与正常水平几乎相一致,但在3mg.iaa/g.lanolin处理材料中的表达则表现为显著的相对上调表达。

综合不同浓度外源IAA处理对杉木维管形成层次生发育及其相关调控基因表达的影响,认为ClWOX4基因表达受到生长素的负向调控,而ClHB8表达则受到生长素的正向调控。

关键词:不同浓度外源IAA 杉木 维管形成层 次生发育 调控基因。

The impact of different concentrations of exogenous IAA on the genes expression associated with Chinese fir vascular cambium secondary development

Abstract

Cambial growth involves the production of secondary xylem and phloem elements, which is the source of trees secondary vascular construction and wood formation.The rate of cambial growth is the major determinant for the production of wood in forest trees, and it is determined by both the radial number of dividing cells in the cambial zone and the rate of cell division for each of the cambial zone cells. By using the sensitive and sepecific gas chromatography-mass spectrometry technique, Claes Uggla, et al (1996) founded the existence of a steep radial concentration gradient of the endogenous auxin, indole-3-acetic acid, over the lateral meristem reponsible for the bulk of pine secondary growth, the vascular cambium. Later, it has confirmed the the polar distribution of IAA also exists in poluplus vascular cambium zone. All these findings suggests auxin maybe provide location signals for cambium secondary development by this approch.

    In this study, we analyzed the expression trend of ClWOX4 and ClHB8,cloned by PCR method using of degenerate primers designed according to the conserved sequence of homologous proteins in arabidopsis and populus,etc,in different concentrations of exogenous auxin - lanolin mixture (0,1 and 3mg.iaa/g.lanolin) treating Chinese fir clone "yangkou020" one-year-old stem by real-time quantitative PCR (qPCR) Technology, the results are as follows:
     1) The full-length of Chinese fir ClWOX4 ,ClHB8 were 1571bp and 2493bp respectively. By blastened with homologous protein sequences in genbank database and phylogenetic tree analysis ,it showed that they were homologous with Arabidopsis AtWOX4 and AtHB8 respectively (e-value lt;10-4);
    2)By tissue-specific expression analysis, it found that the expression of ClWOX4 is homogeneous in secondary phloem, vascular cambium and secondary xylem region ,however,the expression of ClHB8 mainly focused on the adaxial region of secondary developing vascular ;
    3) ClWOX4 showed continued upregulated relative to normal expression levels in phase of developmening stem treated by 0mg.iaa/g.lanolin mixture.however, it showed relatively stable expression in 1mg.iaa/g.lanolin processed materials, only in the early processing stage, showed downregulated relative to the normal level and up-regulated in the later; The influence of 3mg.iaa/g.lanolin on ClWOX4 gene expression was similar to the normal growth material, the expression showed a gradual decline, but performance increased significantly relative to normal levels
    The expression of ClHB8 gene in different concentrations of exogenous IAA treating materials was consistent with the normal level and showed high to low expression trend, especially in which 0 and 1mg.iaa/g.lanolin treating materials. But in 3mg.iaa/g.lanolin processing materials, it showed up-regulated significantly.
    Integrated with different concentrations of exogenous IAA on the influence of Chinese fir vascular cambium secondary development and the impact of gene expression, it suggested that the expression of ClWOX4 and ClHB8 were regulated negatively and positively by auxin.

Key Words: different concentrations of exogenous IAA;Chinese fir;ClWOX4 and ClHB8;influence of gene expression.

目 录

前言 1

1.文献综述 1

您需要先支付 80元 才能查看全部内容!立即支付

课题毕业论文、开题报告、任务书、外文翻译、程序设计、图纸设计等资料可联系客服协助查找,优先添加企业微信。