文献类型：期刊文献

中文题名：杨树中I类KNOX基因结构、表达与功能分析

英文题名：Structure,Expression and Function Analysis of Class I KNOX Genes in Populus

作者：赵岩秋[1] 周厚君[1] 魏凯丽[1] 江成[1] 宋学勤[1] 卢孟柱[1]

第一作者：赵岩秋

机构：[1]林木遗传育种国家重点实验室,中国林业科学研究院林业研究所,北京100091

年份：2018

卷号：31

期号：4

起止页码：118-125

中文期刊名：林业科学研究

外文期刊名：Forest Research

收录：CSTPCD;;Scopus;北大核心:【北大核心2017】；CSCD:【CSCD2017_2018】；

基金：林业公益性行业科研专项“林木顶端分生组织发育及环境适应性机制研究”(201504101)

语种：中文

中文关键词：I类KNOX;分生组织;形成层;表达分析;杨树

外文关键词：class I KNOX;meristem;cambium;expression analysis;Populus

分类号：S718.46

摘要：[目的]分生组织对器官发生和形态建成起到至关重要的作用,其活性受多种转录因子的调控。KNOTTEDlike homeobox(KNOX)基因家族由2个亚类即I类和II类KNOX组成,在模式植物拟南芥中I类KNOX成员主要在茎的顶端分生组织区域表达,对维持顶端分生组织分化及侧生器官的形态建成过程起关键作用。木本植物生长发育过程主要包含以顶端分生组织(Shoot apical meristem,SAM)为中心的初生生长与以形成层为中心的次生生长过程,本研究通过分析杨树I类KNOX基因在SAM、根顶端分生组织(Root apical meristem,RAM)的形成过程及形成层相关区域的表达,探讨I类KNOX基因在杨树分生组织形成与分化过程中的功能。[方法]以拟南芥I类KNOX基因STM的蛋白序列在毛果杨基因组中进行同源比对分析,获取杨树I类KNOX成员的核酸和氨基酸序列。根据核酸及氨基酸序列信息构建系统发育树,并绘制基因结构与蛋白质结构图谱。利用84K杨(Populus alba×P.glandulosa)不定芽与不定根诱导实验体系模拟顶端分生组织发育过程,通过实时定量PCR(RT-PCR)技术,对杨树I类KNOX成员在不定芽与不定根形成过程及形成层相关区域中的表达进行分析。[结果]本研究通过同源比对分析鉴定出10个杨树I类KNOX成员,根据进化关系与基因结构差异将其分为三组:组1、组2、组3,其中,组1为拟南芥KNAT2和KNAT6同源基因,组2为STM和BP同源基因,组3为杨树所特有的I类KNOX基因。杨树I类KNOX基因在不定芽与不定根发生过程中表达量均发生较大的变化,在不定芽发生过程中,组1基因在芽原基分化产生不定芽的关键期上调表达,而组2与组3基因多在分生组织分化产生芽原基阶段高表达;在不定根发生过程中,组1成员多在根原基分化产生不定根的过渡期上调表达,组2与组3基因则多在发育后期不定根形态建成阶段高表达。杨树I类KNOX成员在形成层相关区域均表达,组1中KNAT2/6与组2中STM、BP同源基因的表达量明显高于其他成员。[结论]以上结果说明,杨树I类KNOX除了与拟南芥同源的2个组外,还进化产生新的组别,分别参与分生组织形成和分化过程中不同阶段的调控,且Pt KNAT2/6b、ARK1与ARK2在形成层区域高表达,提示以上3个基因可在形成层功能维持以及木质部分化中发挥主要作用。
[ Objective ] The expression of Populus class I KNOX genes during the ~generation of adventitious shoot and adventitious root as well as in the vascular cambium were analyzed to reveal the function of class I KNOX genes in woody plants meristem formation and differentiation. [ Method ] The nucleic acid and amino acid sequence of Populus class I KNOX genes were obtained through blast analysis using Arabidopsis STM protein sequence as query in the genome of Populus trichocarpa. The phylogenetic tree was constructed according to the full length protein se- quences of class I KNOX genes from Arabidopsis and Populus. The intron/exon structure and domain composition were presented along the phylogenetic tree. The regeneration of adventitious bud and adventitious root using leaf and stem explants from 84 K （Populus alba x P. glandulosa） was used to simulate the shoot and root apical meristem initiation and differentiation, respectively. Quantitative real-time PCR was carried out to analyze the expression of Populus class I KNOX genes during the regeneration of adventitious bud/root and in the vascular cambium related region. [ Result] Ten class I KNOX genes were found in the genome of P. trichocarpa through sequence alignment analysis. According to the phylogenetic relationship and gene structure similarity, class I KNOX genes from Arabi- dopsis and Populus could be divided into three groups. Arabidopsis KNAT2 and KNAT6 along with their Populus homolog genes belong to group 1, Arabidopsis STM and BP along with their Populus homolog genes belong to group 2. Group 3, to be noticed, was unique to Populus. Through investigating the expression alteration of Populus class I KNOX genes during the regeneration of adventitious buds, it was found that group 1 genes showed increased ex- pression during the transition from bud primordium to adventitious bud, while group 2 and group 3 genes demonstra- ted higher expression during the transition from meristem to bud primordium. As for the regeneration of adventitious root, group 1 genes showed increased expression in the stage when root primordium differentiate to adventitious root, while group 2 and group 3 genes demonstrated higher expression in the adventitious root formtion stage. In addi- tion, all Populus class I KNOX genes had an expression in the vascular cambium, and the expression of group 1 gene PtKNAT2/6b and group 2 genes ARK1 and ARK2 welre especially high. [ Conclusion] Group 3 is a new group occuTed during the evolution of class I KNOX genes from A. thaliana to P. trichocarpa, which was along with group 1 and group 2 to participate in the regulation of different stages of meristem formation and differentiation. Most importantly, PtKNAT2/6b, ARK1 and ARK2 show high expression in the vascular cambium, which may play impor- tant roles in vascular cambium activity maintenance and xylem differentiation.