植物离体培养中器官发生调控机制的研究进展

本文就离体培养的植物组织对生长调节物质的吸收和代谢，外源生长调节物质对内源激素水平的影响，内源激素对细胞脱分化和再分化的调控，生长素和细胞分裂素基因与器官发生的关系，与器官发生有关的基因和特异蛋白等问题的研究进展进行了评述，并对下一步研究提出了自己的看法。     

microRNA调控女性生殖功能的研究进展

女性生殖功能的正常维持受多种因素的影响,既与生殖细胞和体细胞之间的相互作用密切相关,又有赖于激素、细胞因子和基因等调节物质及时准确的调节。这些调节因素调控生殖系统各个器官的细胞活动,包括细胞生长、增殖、分化和凋亡,其功能紊乱会导致生殖功能障碍,如不孕、多囊卵巢综合征、生殖道肿瘤的发生等。microRNA(miRNA)是一类单链的,内源性非编码的小RNA,大小一般为18~24核苷酸,通过调节靶基因的转录后水平,调节细胞的发育、增殖、凋亡、分化和功能等。目前研究发现miRNA在卵巢、子宫、输卵管、胚胎发育及病变过程中有调控作用。本文将对miRNA的生物合成,以及其表达在女性生殖系统正常和病理条件下可能的调控作用作一综述。     

Hippo信号通路生物学作用研究进展

Hippo信号通路是20世纪末在黑腹果蝇中进行基因筛选时发现的,该通路受各种生化、物理和结构信号的影响,调控细胞生长、分化,组织和器官发育以及内环境稳态等基本生物学过程。研究表明Hippo信号通路失调会引起一系列疾病的发生。本文阐述了目前Hippo信号通路在胚胎发育、器官和组织稳态调节、肿瘤的发生发展和细胞自噬等一系列生物学过程以及靶向治疗中的研究进展,其中Hippo信号通路通过细胞自噬来维持机体细胞内环境稳态成为新的研究热点。对该通路的功能和调控机制的深入研究也为组织器官修复再生医学及癌症治疗提供参考。     

miRNAs对血管平滑肌细胞功能的调节与心血管疾病

miRNA(miRNAs)是一类长约18～24个核苷酸的高度保守性的小分子非编码RNA,主要通过与特异性靶基因mRNA 3’-UTR区结合来调控基因的表达。miRNAs与细胞增殖、分化、凋亡、胚胎发育、组织器官等形成以及多种疾病的发生发展密切相关。新近研究显示,miRNAs对血管心血管平滑肌细胞功能及心血管疾病的发生发展起着重要的调节作用。本文就miRNAs对血管平滑肌细胞功能的调节及心血管疾病的病理生理学意义作一概述。     

花同源异型基因FBP2调节叶片中过氧化物酶的表达

对碧冬茄和烟草的野生型以及FBP2转化植株(transformant)叶片中过氧化物酶 (POD)的特性做了分析 ,结果表明FBP2在花中的表达可以调节叶片特异POD的表达 ,并影响其活性。此外 ,FBP2在花中的表达还影响叶片内源植物生长物质的水平以及多酚氧化酶 (PPO)和过氧化氢酶 (CAT)的活性。结果表明 :花同源异型基因不仅调控花器官的发育 ,而且参与营养器官代谢的调节 ,使之适应于生殖器官的生长发育     

6-苄基腺嘌呤(BA)对烟草愈伤组织芽器官分化过程的调节作用(简报)

在外源激素调节烟草愈伤组织器官分化类型的研究中,细胞激动素类物质对芽器官形成的促进作用是显而易见的。但是这一类物质究竟怎样使高等     

植物生长物质的应用

一、植物生长物质的概念 生长物质的分类 植物生长物质是指能够调节和控制植物生长发育的一类化学物质。可分为植物自身合成的内源激素和人工合成的生长调节剂。前者包括生长素类(IAA)、赤霉素类(GA)、细胞分裂素类(CTK)、脱落酸     

C类花器官特征基因AGAMOUS(AG)调控植物花分生组织维持与终止研究进展

花分生组织的维持与终止在植物花器官发生和世代交替起着至关重要的作用。成功的花分生组织决定能够确保植物正常的生殖发育和生命周期进程。诸多研究表明AGAMOUS(AG)基因作为花器官分化和开花决定的主效调节因子,能够协调花发育过程中多种细胞命运决定。然而,关于AG参与调控植物世代交替及花分生组织维持与终止的分子调控机制尚不清晰。综述了近年来AG基因参与调控植物花分生组织维持与终止的研究进展及现状,以期为深入研究植物花器官分化过程中干细胞的维持和终止,以及干细胞活动与其他发育过程之间的分子调控过程提供参考。     

植物的分化及其影响因素

植物界中 ,不论是低等的藻类还是高等的被子植物 ,都是由 1个细胞发育而来的 ,或者是低等藻类的孢子 ,或者是高等植物的合子——受精卵。从 1个细胞发育成具有多种组织结构的植物体 ,在这一过程中离不开分化。1　分化的概念狭义的分化是指细胞分化 ,即产生出不同类型的细胞。广义的分化则包括了组织分化与器官分化 ,即形成不同的组织和器官 ,主要侧重于从细胞或分子角度研究构成植物体的各部分如何发生差异。分化与生长是不同的 ,生长是植物体积的增大 ,而分化是不同组织或器官的形成 ,如果 1个细胞分裂成两个完全相同的细胞则是生长。如果…     

microRNA参与植物次生代谢与非生物胁迫的调控

微RNA(microRNA,miRNA)为广泛存在于真核生物中的约16 ～ 29个核苷酸长度的内源非编码单链RNA分子,在植物中参与细胞增殖、分化、代谢、器官形成以及抵御盐、温度、干旱、重金属胁迫等方面的调节.植物miRNA主要通过对靶基因降解或抑制靶基因的表达,影响植物的生长发育.目前对miRNA的产生与调控方式的研...     

植物激素糖基化修饰研究进展

植物激素对植物的生长发育有重要的调节作用。由于激素的作用依赖于其浓度, 所以植物内源活性激素的水平必须受到严格控制, 而糖基化修饰被认为是调控激素活性水平的重要方式之一。随着植物激素糖基化修饰相关糖基转移酶基因不断被克隆与鉴定, 多种植物激素的糖基化修饰机制和功能作用逐渐被揭示。该文重点介绍了近年来植物生长素、细胞分裂素、脱落酸、油菜素内酯、水杨酸、茉莉酸等植物激素的糖基转移酶活性鉴定与功能研究进展。同时, 对植物激素糖基化修饰领域存在的问题和发展前景进行了讨论。     

杀菌剂敌磺钠及植物生长调节剂对茭白孕茭的影响

以‘龙茭二号’为研究对象,通过在茭白植株不同生长发育阶段分别喷施杀菌剂敌磺钠和植物生长调节剂,比较分析其对茭白结茭的促进效果。对6个不同处理组合及对照材料的株高、内源激素含量变化及结茭情况的统计分析发现：喷施一定浓度的敌磺钠对茭白结茭具有明显的促进作用,以敌磺钠（标准浓度）＋营养液和敌磺钠（标准浓度）对茭白结茭产量的提高最为明显。植物生长调节剂处理能明显促进茭白早期植株生长,但对最终株高影响不大。采用间接酶联免疫法对茭白茎部3种激素（IAA、ABA和GA3）含量进行的比较分析表明：敌磺钠处理能够明显降低ABA含量,但对IAA和GA3含量没有明显影响;茭白结茭前ABA含量的降低可能有助于茭白结茭。     

Levels of endogenous abscisic acid and indole-3-acetic acid influence shoot organogenesis in callus cultures of rice subjected to osmotic stress

Osmotic stress and endogenous hormone levels may have a role in shoot organogenesis, but a systematic study has not yet to investigate the links. We evaluated the changes of the endogenous indole-3-acetic acid (IAA) and abscisic acid (ABA) levels in rice (Oryza sativa L. cv. Tainan 5) callus during shoot organogenesis induced by exogenous plant growth regulator treatments or under osmotic stress. Non-regenerable callus showed low levels of endogenous ABA and IAA, with no fluctuation in level during the period evaluated. The addition of 100 μM ABA or 2 mM anthranilic acid (IAA precursor) into Murashige and Skoog basal induction medium containing 10 μM 2,4-D enhanced the regeneration frequency slightly, to 5 and 35%, respectively, and their total cellular ABA or IAA levels were increased significantly, correspondingly to the treatments. However, the regeneration frequency was greatly increased to 80% after treatment with 0.6 M sorbitol or 100 μM ABA and 2 mM anthranilic acid combined. Both treatments produced high levels of total cellular ABA and IAA at the callus stage, which was quickly decreased on the first day after transfer to regeneration medium. Thus, osmotic stress-induced simultaneous accumulation of endogenous ABA and IAA is involved in shoot regeneration in rice callus.     

Perspective of plant growth promoting rhizobacteria (PGPR) containing ACC deaminase in stress agriculture

Ethylene is a gaseous plant growth hormone produced endogenously by almost all plants. It is also produced in soil through a variety of biotic and abiotic mechanisms, and plays a key role in inducing multifarious physiological changes in plants at molecular level. Apart from being a plant growth regulator, ethylene has also been established as a stress hormone. Under stress conditions like those generated by salinity, drought, waterlogging, heavy metals and pathogenicity, the endogenous production of ethylene is accelerated substantially which adversely affects the root growth and consequently the growth of the plant as a whole. Certain plant growth promoting rhizobacteria (PGPR) contain a vital enzyme, 1-aminocyclopropane-1-carboxylate (ACC) deaminase, which regulates ethylene production by metabolizing ACC (an immediate precursor of ethylene biosynthesis in higher plants) into α-ketobutyrate and ammonia. Inoculation with PGPR containing ACC deaminase activity could be helpful in sustaining plant growth and development under stress conditions by reducing stress-induced ethylene production. Lately, efforts have been made to introduce ACC deaminase genes into plants to regulate ethylene level in the plants for optimum growth, particularly under stressed conditions. In this review, the primary focus is on giving account of all aspects of PGPR containing ACC deaminase regarding alleviation of impact of both biotic and abiotic stresses onto plants and of recent trends in terms of introduction of ACC deaminase genes into plant and microbial species.     

Tuning the cell-cycle engine for improved plant performance

Cell-cycle regulation plays a crucial role in organogenesis, morphogenesis, growth and differentiation and conceptually offers a means to design a next generation of crop plants that outperform traditionally bred ones. However, cell-cycle regulation involves a large, highly redundant, set of genes, which complicates unravelling of function in the context of a higher plant. Nevertheless, ten years of molecular cell-cycle research, primarily in the model plant Arabidopsis, have demonstrated its potential for altering plant development.     

The ethylene signal transduction pathway in Arabidopsis

The gaseous hormone ethylene is an important regulator of plantgrowth and development. Using a simple response of etiolatedseedlings to ethylene as a genetic screen, genes involved inethylene signal transduction have been identified in Arabidopsis.Analysis of two of these genes that have been cloned revealsthat ethylene signalling involves a combination of a protein(ETR1) with similarity to bacterial histidine kinases and aprotein (CTR1) with similarity to Raf-1, a protein kinase involvedin multiple signalling cascades in eukaryotic cells. Severallines of investigation provide compelling evidence that ETR1encodes an ethylene receptor. For the first time there is aglimpse of the molecular circuitry underlying the signal transductionpathway for a plant hormone. Key words: Ethylene, plant growth, plant development, regulation, signal transduction, Arabidopsis     

Levels and immunolocalization of endogenous cytokinins in thidiazuron-induced shoot organogenesis in carnation

We evaluated the capacity of the plant growth regulator thidiazuron (TDZ), a substituted phenylurea with high cytokinin-like activity, to promote organogenesis in petals and leaves of several carnation cultivars (Dianthus spp.), combined with 1-naphthaleneacetic acid (NAA). The involvement of the endogenous auxin indole-3-acetic acid (IAA) and purine-type cytokinins was also studied. Shoot differentiation was found to depend on the explant, cultivar and balance of growth regulators. TDZ alone (0.5 and 5.0 micromol/L) as well as synergistically with NAA (0.5 and 5.0 micromol/L) promoted shoot organogenesis in petals, and was more active than N6-benzyladenine. In petals of the White Sim cultivar, TDZ induced cell proliferation in a concentration-dependent manner and, on day 7 of culture, the proportion of meristematic regions in those petals allowed the prediction of shoot regeneration capacity after 30 days of culture. Immunolocalization of CK ribosides, N6-(delta2-isopentenyl)adenosine, zeatin riboside (ZR) and dihydrozeatin riboside (DHZR), in organogenic petals showed them to be highly concentrated in the tips of bud primordia and in the regions with proliferation capacity. All of them may play a role in cell proliferation, and possibly in differentiation, during the organogenic process. After seven days of culture of White Sim petals, NAA may account for the changes found in the levels of IAA and DHZR, whereas TDZ may be responsible for the remarkable increases in N6-(delta2-isopentenyl)adenine (iP) and ZR. ZR is induced by low TDZ concentrations (0.0-0.005 micromol/L), whereas iP, that correlates with massive cell proliferation and the onset of shoot differentiation, is associated with high TDZ levels (0.5 micromol/L). In addition to the changes observed in quantification and in situ localization of endogenous phytohormones during TDZ-induced shoot organogenesis, we propose that TDZ also promotes growth directly, through its own biological activity. To our knowledge, this study is the first to evaluate the effect of TDZ on endogenous phytohormones in an organogenic process.     

Ethylene gas: perception, signaling and response

During the last decade a genetic approach based on the Arabidopsis 'triple response' to the hormone ethylene has allowed the identification of numerous components of the signal transduction pathway. Cloning of the genes and biochemical analysis of the proteins that they encode are uncovering the molecular mechanisms that allow a plant cell to perceive and respond to this gaseous regulator of plant growth/stress responses.