植物LEAFY同源基因的研究进展

本文就近10年来LEAFY(简写为LFY)同源基因的研究进展做了综合分析.通过对19种植物中已分离到的LFY同源基因的序列比较分析发现:LFY同源基因编码区核苷酸和氨基酸序列同源性都较高;在双子叶植物基因组中,拷贝数却有所不同.该基因的表达特性显示其在不同植物中表达的时间和空间有所差异.根据已知序列推导的氨基酸序列构建的系统进化树表明,单子叶植物与裸子植物的亲缘关系近于双子叶与裸子植物的亲缘关系.上述研究资料为植物成花机理研究提供了重要参考,且在研究植物系统进化方面也具有重要的意义.     

LEAFY同源基因研究进展

LEAFY(LFY)同源基因存在于所有的陆生植物中,在植物花发育早期表达,并在花发育过程中抑制茎端分生组织的营养生长,调控花分生组织和花器官的形成,使转LFY基因植株提前开花,LFY同源基因与其上下游基因共同调控花发育过程.LFY同源基因的蛋白质结构在不同物种间保守性很高,但它们的表达部位差异很大.该文总结了近年来国内外已经克隆到的LFY同源基因的表达、功能及其在果树、花卉、粮食作物上的应用,以期为植物花发育的深入研究提供参考.     

拟南芥LEAFY基因在花发育中的网络调控及其生物学功能

重点综述了拟南芥花分生组织特征基因——LEAFY（LFY）基因及其同源基因在花发育中的网络调控及其生物学功能。LFY基因广泛表达于高等植物的营养性和生殖性组织。LFY基因需要与其他基因相互作用,並且表达量达到一定水平时才能促进成花。LFY基因处于成花调控网络的关键位置,不仅调控开花时间和花转变,而且在花序和花的发育中也起重要作用。碳源、植物激素等因子直接或间接地影响LFY基因的表达和作用。提示通过掌握LFY基因的表达调控规律进一步探讨成花机理的可行性。 Abstract:Recent research progress on regulation network and biological roles of LFY gene in Arabidopsis thaliana and its homologue genes in floral development are reviewed emphatically in the present paper.LFY gene expresses widely in both vegetative and reproductive tissues in different higher plants,therefore investigation on role of LFY gene on flowering is of general significance.LFY gene plays an important role to promote flower formation by interaction and coordination with other genes,such as TFL,EMF,AP1,AP2,CAL,FWA,FT,AP3,PI,AG,UFO,CO,LD,GA1 etc,and a critical level of LFY expression is essential.LFY gene not only controls flowering-time and floral transition,but also plays an important role in inflorescence and floral organ development.It was situated at the central site in gene network of flowering regulation,positively or negatively regulates the level or activities of flowering-related genes.Some physiological factors,such as carbon sources,phytohormones,affect directly or indirectly the expression and actions of LFY gene.This indicates that level of LFY expression can also be regulated with physiological methods.It is probable that we can explain the principal mechanism of flowering by regulation network of LFY gene.     

高等植物的同源异型基因

最近几年,对植物中同源异型基因的研究正日益引人注目,并且取得了很大进展。以一些模式植物（例如拟南芥和金鱼草）局部组织的形态发育过程为研究系统,将传统经典遗传学方法和现代分子遗传学技术相结合,已经分离了许多在植物器官发育中起重要作用的同源异型基因,并初步阐述了这类基因的功能和分子之间相互调控的概约作用框架。     

植物同源异型基因及同源异型盒基因的研究进展

植物同源异型基因及同源异型盒基因是涉及植物个体发育调节的两类重要转录因子编码基因.近10年来的研究表明,这两类基因及其产物的结构与功能具有明显的差异.深入研究这两类基因的结构与功能对揭示植物的发育机制具有重要意义.     

黄瓜中LFY同源基因CFL的克隆和分析

ＬＦＹ同源基因在高等植物花分生组织的发生中发挥着重要的作用。克隆了黄瓜（ Ｃｕｃｕｍｉｓｓａｔｉｖｕｓ Ｌ．） 中的ＬＦＹ同源基因ＣＦＬ,Ｓｏｕｔｈｅｒｎ 杂交的结果显示它在黄瓜基因组中为单拷贝基因,Ｎｏｒｔｈｅｒｎ 杂交结果显示它主要在花芽和幼叶中表达。讨论了ＣＦＬ基因在黄瓜开花和营养生长中可能发挥的作用     

植物同源异型枢基因的研究进展

植物同源异型枢基因是涉及到植物个体发育的一类重要转录因子编码基因.这类基因及其编码蛋白的结构具有明显的保守性,在植物中广泛存在,研究这类基因,对于揭示植物的发育机制具有重要意义.     

同源异型基因对花器官发育的调控

以ABC模型为基础,阐述了花器官发育调控的分子机制,对一些相关基因在其中的作用和研究进展作了介绍.     

银杏LEAFY同源基因的时空表达

以银杏雄株、雌株成年树和还未开过花的幼树的根、茎、叶,雌株幼果和不同时期的雄花芽、雌花芽为材料,利用同位素标记,制备Ginlfy和GinNdly两个特异探针,进行Northern分子杂交,研究银杏LFY同源基因Ginlfy、GinNdly在银杏不同器官,花芽不同生长发育时期的时空表达情况。结果显示,无论是幼树,还是成年的雌株、雄株,Ginlfy基因在各个器官,如根、茎、叶、雌花芽、雄花芽、幼果以及雌花芽、雄花芽的不同发育时期都有表达,属组成型表达,而GinNdly基因只在叶和不同时期的雄花芽、雌花芽中表达,其他器官都不表达,属特异性表达。银杏双拷贝LFY同源基因中的GinNdly基因可能与开花关系更为密切。 Abstract: Expressions of Ginlfy and GinNdly gene were studied by northern blotting in different organs and stages of Ginkgo Biloba. Ginlfy gene was expressed in different organs such as root, stem, leaf of juvenile tree, male tree and female tree, and in different stages of male flower bud and female flower bud. It was inferred that Ginlfy gene could be expressed constitutionally. GinNdly gene was only expressed in leaf of juvenile tree, male tree and female tree and in different stages of male flower bud and female flower bud, while GinNdly gene was not expressed in the other organs. Therefore it was thought that GinNdly gene could be expressed differentially and be a close relation to development of flower.     

植物冷驯化相关基因研究进展

冷驯化是与提高植物抗冷性有关的生物化学及生理学过程,主要包括寒驯化（cool acclimation）和冻驯化（freezing acdimation）。在冷驯化过程中,植物体内许多基因在转录水平上的表达受到影响,已经克隆了大量的相关基因,它们组成复杂的分子调控网络。目前研究表明不依赖ABA的低温信号转导途径是植物冷驯化机制的重要组成部分,其中CBF/DREB1是该调控过程的关键转录因子,与植物通过冷驯化而提高冰冻耐受能力密切相关。进一步利用转基因技术,可以有效地改善作物的耐冷性状。     

植物冷驯化相关基因研究进展

摘要 冷驯化是与提高植物抗冷性有关的生物化学及生理学过程, 主要包括寒驯化(cool acclimation)和冻驯化(freezing acdimation)。在冷驯化过程中, 植物体内许多基因在转录水平上的表达受到影响, 已经克隆了大量的相关基因,它们组成复杂的分子调控网络。目前研究表明不依赖ABA的低温信号转导途径是植物冷驯化机制的重要组成部分, 其中CBF/DREB1是该调控过程的关键转录因子, 与植物通过冷驯化而提高冰冻耐受能力密切相关。进一步利用转基因技术, 可有效地改善作物的耐冷性状。     

高等植物成花基因的研究

高等植物的成花可分为两个阶段：由茎顶端分生组织转变成花分生组织和花器官的形成。前者主要受成花计时基因的控制,而后一阶段主要由植物的同源（异型）框基因调控。本文综述了近年来对植物成花调控基因的研究,并着重对第一阶段成花基因的功能、它们间的相互作用和特点进行了总结。 Abstract:Plant flower can be divided into two phases——from stem apex meristem tissue into flower meristem tissue and floral apparatus.The flower time genes control the flower development and the homologous genes control flower apparatus identify.This paper summarizes recent studies on plant flower and emphasizes on the first phase flower control genes,theirs interaction and function,characteristic of the homologous genes.     

Investigation on the Conserved MicroRNA Genes in Higher Plants

Analysis of evolving microRNA repertoires within the plant domain can further corroborate our understanding of genome evolution and plasticity. An extensive collection of relatively unbiased miRBase-registered plant miRNAs and predicted unlisted MIRs from 23 plant ESTs were examined. As a result, 4324 pre-miRNAs were predicted and classified in 656 miRNA gene families with mostly being transposons (57.81%). From 216 newly identified pre-miRNAs, 103 distinct types belonged to reduced complexity/repeated regions. Collinearity between the numbers of miRNAs in each species with the relevant sizes of genomes was absent. Duplications of MIRs were evident, with higher MIR paralogs in Liliopsida compared with dicots. Due to the lack of an apparent pattern of phylogeny, Dollo maximum parsimony was used that established the acceleration of gains and potential losses of miRNA gene families within Mesangiospermae during the last 200 million years ago. Phylogenetic analysis of Liliopsida in contrast to Eudicotyledons agreed with the reconstructed tree based on the possible expansion of distinguished MIR families. In marked contrast to dicots, the degrees of resemblance in Liliopsida were higher than their direct predecessors. Analyses of recent monophyletic lineages were illustrative of miRNA horizontal genes transfer.

     

Studies on Protein Metabolism in Higher Plants

Changes in ribulose diphosphate (RuDP) carboxylase activity and the content of fraction 1 protein, which had been elucidated to be identical with protein of RuDP carboxylase, in tobacco leaves were examined with age, comparing with change in total protein content. Fraction 1 protein was determined by an immunological precipitin method developed in this experiment. Fraction 1 protein decreased with age and the rate was similar or a little larger than those of total protein and total chlorophyll. The carboxylase activity decreased more rapidly than fraction 1 protein during the senescent process. In a plant, upper leaves showed higher values of the carboxylase activity and fraction 1 protein content than lower leaves. The specific activity, RuDP carboxylase activity per unit fraction 1 protein, in upper leaves was higher than that in lower leaves.     

Studies on Protein Metabolism in Higher Plants

A leaf protease of tobacco whose activity was enhanced during curing was purified about 60 times with ammonium sulfate fractionation, ethanol precipitation, calcium phosphate gel treatment and Sephadex G-200 column chromatography, and some properties of the protease were examined. The purified enzyme showed the optimum pH at 5.5 and the optimum temperature at 60°C. The protease activity was stable between pH 4.5 and 5.5 at 50°G or at pH 5.5 below 40°C for 1 hr, but completely destroyed at 70°C during 1 hr. The protease activity was greatly activated by reducing agents such as cysteine, glutathione or mercaptoethanol and inhibited by p-chloromercuribenzoate, phenyl- mercuric acetate or silver ions. Metal ions except for silver ion and ethylenediamine tetraacetic acid did not affect the protease activity so far examined.