植物体细胞胚发生过程中基因表达的研究进展

植物体细胞胚胎发生是一个复杂的发育过程,研究者们通过分析植物体细胞胚发生过程中的基因表达或胚性组织和非胚性组织中基因的差异表达,获得了在体细胞胚发生过程不同时期表达的基因,并分析了这些基因在胚胎发生途径中可能的作用。综述了在植物体细胞胚发生过程中细胞周期相关基因、胁迫和激素应答相关基因、信号转导相关基因、晚期胚胎丰富蛋白基因及与体细胞胚发生相关的胞外蛋白基因表达的研究进展。     

植物体细胞胚胎发生及其相关应答基因的研究进展

体细胞胚胎发生途径不仅是植物大规模克隆繁殖的重要途径,也是研究从单细胞到整体植株发育全过程的理想试验体系。植物体细胞胚胎发生的研究已经取得了很大的进展,但是也依然存在许多问题。根据近年来的相关研究报道,简述植物体细胞胚胎发生及此过程中相关应答基因的研究概况,探讨植物体细胞胚胎发生的生理生化基础,并对今后应该加强研究的关键问题提出了自己的看法。     

乙烯和多胺的生物合成与植物体细胞胚胎发生

综述了乙烯、多胺生物合成与植物体细胞胚胎发生的关系,以及乙烯和多胺生物合成的互相调节对植物体细胞胚胎发生的影响。     

植物体细胞胚胎发生的诱导与调节研究进展

植物体细胞胚胎发生的诱导与调节研究进展陈以峰（江苏省农科院遗传生理所,南京２１００１４）植物体细胞胚胎发生是一个复杂的发育过程,受到多种内、外因素的影响与调节,研究体细胞胚胎发生诱导与调节既是一个基本的理论问题,更为重要的是,这方面的成果为提高植株再...     

松杉类植物体细胞胚发育机理的研究进展

植物体细胞胚胎发生不仅可作为其繁育的重要手段,而且也是研究胚胎发育过程的一种重要模式系统.体细胞胚在形态和生理上的成熟,直接影响到植株的萌发和再生频率.本文综述了近年来国内外有关裸子植物中几种松杉类植物体细胞胚发育过程的研究报道,其中主要涉及培养基成分和脱落酸(ABA)对体细胞胚发育的影响,以及体细胞胚发育在细胞学、细胞程序性死亡、相关基因和蛋白质组学等方面的研究进展,并进一步讨论了松杉类植物体细胞胚的发育机理,以及体细胞胚在遗传转化系统中的作用.     

落叶松树种的体细胞胚胎发生与规模化技术体系

植物体细胞胚胎发生技术是植物体细胞在人为可控条件下通过与合子胚胎发生类似的途径 ,发育出新个体的再生技术 ,自问世以来 ,已被广泛用于生命科学领域。对落叶松及其杂种胚性细胞系的大规模增殖培养、原胚发育状态、体细胞胚成苗和专用生物反应器技术体系的建立以及其应用、展望等方面进行了探讨 ,表明落叶松体细胞胚胎发生过程中专用生物反应器技术体系的完善与建立迫在眉睫 ,并将为现代林木育种与繁殖工程及生命科学相关学科的发展带来重要影响 。     

植物体细胞胚胎发生研究的某些现状

植物体细胞在离体培养中通过体细胞胚胎发生(embryogenesis)途径形成再生植株已是极其普遍的现象。由于这一发育途径为研究植物细胞的分化、发育、全能性表达和作物品种改良、突变体筛选等提供了良好的体系,在理论上和应用中都具有重大意义,因而引起了     

禾本科植物组织培养中的体细胞胚胎发生

在植物组织培养中,形态发生的途径通常有两条:一条是器官发生(Organogensis),另一条是胚胎发生(Embryogenesis)。在胚胎发生途径中形成类似合子胚而被称为胚状体的结构。根据外植体的不同来源,胚状体又可分为两类,即由普通植物体的各种器官、组织等的二倍体细胞产生的体细胞胚(Somatic embryos)和由小孢子或其分裂产物等单倍体细胞产生的花粉胚(Polleuembryos)。本文主要论述体细胞胚胎的发生。     

蔷薇科植物体细胞胚胎发生及影响因素研究进展

总结了近30年来蔷薇科植物体细胞胚胎发生及影响因素的研究进展。蔷薇科植物体胚发生多数是直接发生途径和间接发生途径同时存在,但以间接发生途径为主。合子胚作为外植体明显好于营养器官作为外植体。诱导体胚发生的植物生长素类调节剂以NAA、2,4-D为主,细胞分裂素类调节剂以6-BA为主,少数植物种类的体胚诱导需要添加KT。冷处理对蔷薇科植物的体胚分化有效。光照对蔷薇科植物的体胚发生没有显著的影响,有时光照会抑制体胚发生。今后应逐步开展对蔷薇科植物体细胞胚胎发生的生理、生化及分子机理的研究,这在蔷薇科植物的新品种培育、遗传改良、优良单株的离体扩殖等具有重要意义。     

植物体细胞胚发生的分子基础

植物通过体细胞胚胎发生途径形成再生植株已是及其普遍的现象,这一发育途径为研究植物细胞的分化、发育、全能性表达和作物品种改良、突变体筛选等提供了良好的实验体系,在理论上和应用中都具重大意义.体细胞分化为胚性细胞是受细胞内外多种因子所调控[1, 2],其中最重要的是受特定基因的调控,在胚性细胞的分化过程中伴随着特定的遗传信息表达,其分化过程的实质是基因按顺序表达调控,是相应基因产物作为胚性细胞形成的分子基础.本文结合我们的工作来探讨体细胞胚发生分子基础研究现状.     

脱落酸与植物体细胞胚胎发生关系的研究进展

简要综述了植物体细胞胚胎发生过程中内源ABA水平及外源ABA对体细胞胚胎发生和发育的调节作用及其作用机制,并提出了未来的研究方向。     

ABA对枸杞体细胞胚发生的调节作用

Using Enzyme Linked Immunosorbent Assay (ELISA) method, we determined the ABA contents of different stages in somatic embryogenesis. The results showed that endogenous ABA contents increased to maximum value twice during somatic embryogenesis. After first maximum value of ABA contents embryogenic cells were observed in callus, and simultaneously, there was a specific protein of somatic embryogenesis investigated by SDS-PAGE. This protein accumulates preferentially in embryogenic callus but not in transferred callus. So it is suggested that ABA could promote the expression of specific genes and the synthesis of embryogenic protein during somatic embryogenesis in Lycium barbarum L. and ABA play an important role in globular stage as well. In addition, treatment of non-embryogenic activity callus with 4 mumol/L exogenous ABA could stimulate somatic embryogenesis. And the ABA function mechanism in relation to somatic embryogenesis was discussed.     

New insights into plant somatic embryogenesis: an epigenetic view

Somatic embryogenesis plays a significant role in plant regeneration and requires complex cellular, molecular, and biochemical processes for embryo initiation and development associated with plant epigenetics. Epigenetic regulation encompasses many sensitive events and plays a vital role in gene expression through DNA methylation, chromatin remodelling, and small RNAs. Recently, regulation of epigenetic mechanisms has been recognized as the most promising occurrences during somatic embryogenesis in plants. A few reports demonstrated that the level of DNA methylation can alter in embryogenic cells under in vitro environments. Changes or modification in DNA methylation patterns is linked with regulatory mechanisms of various candidate marker genes, involved in the initiation and development of somatic embryogenesis in plants. This review summarizes the current scenario of the role of epigenetic mechanisms as candidate markers during somatic embryogenesis. It also delivers a comprehensive and systematic analysis of more recent discoveries on expression of embryogenic-regulating genes during somatic embryogenesis, epigenetic variation. Biotechnological applications of epigenetics as well as new opportunities or future perspectives in the development of somatic embryogenesis studies are covered. Further research on such strategies may serve as exciting interaction models of epigenetic regulation in plant embryogenesis and designing novel approaches for plant productivity and crop improvement at molecular levels.     

The role of abscisic acid in plant tissue culture: a review of recent progress

Abscisic acid (ABA) plays a significant role in the regulation of many physiological processes of plants. It is often used in tissue culture systems to promote somatic embryogenesis and enhance somatic embryo quality by increasing desiccation tolerance and preventing precocious germination. ABA is also employed to induce somatic embryos to enter a quiescent state in plant tissue culture systems and during synthetic seed research. Application of exogenous ABA improves in vitro conservation and the adaptive response of plant cell and tissues to various environmental stresses. ABA can act as anti-transpirant during the acclimatization of tissue culture-raised plantlets and reduces relative water loss of leaves during the ex vitro transfer of plantlets even when non-functional stomata are present. This review focuses on the possible roles of ABA in plant tissue culture and recent developments in this area.     

Events following ABA treatment of spruce somatic embryos

Summary Abscisic acid (ABA) is involved in various physiological processes in plant growth and in the development of embryos and the maturation of seed. There is still much to learn about the influence of ABA on regulation of gene expression during plant and seed development. Perhaps not surprisingly, ABA has a major role in the stimulation of somatic embryo maturation in several conifer species, especially spruces. In spite of this, our knowledge of the effects of exogenous ABA is incomplete, for example the effect of ABA concentration on its uptake and fate has rarely been investigated during somatic embryo culture, and our knowledge of molecular events in conifer somatic embryo development is very scant. The intent of this review is to summarize some of the recent research in spruce somatic embryo development related to the use of ABA and to the consequence of its use. National Research Council Canada publication no. 40708.     

Effect of Plant Growth Regulators on Somatic Embryogenesis of Peucedanum terebinthaccum

The influence of different plant growth regulators including 2,4-D,ZT, 6-BA and ABA on somatic embryogenesis and the amount of endogenous ABA at different stages of embryogenesis was investigated. The effect of each plant growth regulator changed according to the stage of embryogenesis. The amount of endogenous ABA was rather high in single cell stage, decreased at cell clump and embryogenic cell clump stages and dramatically increased at globular embryo stage. It decreased again as the embryo developed. This change in amount of the endogenous ABA explained very well the difference in the effect of exogenous ABA when applied at different stages of embryogenesis.     

Globulin-1 gene expression in regenerable<Emphasis Type="Italic"> Zea mays</Emphasis> (maize) callus

Since maize callus cultures regenerate plants via somatic embryogenesis, one might expect to find similar proteins in both zygotic embryos and tissue cultures. The 63-kD globulin protein designated GLB1, the expression of which is regulated by abscisic acid (ABA), is one such protein. When maize Type I regenerable callus was exposed for 24 h to 0.1 m M ABA or a water stress induced by 0.53 M mannitol, GLB1 was produced as determined by Western analysis. This protein was not detected in ABA or mannitol-treated regenerable cultured tissue of a null genotype or in tissues not exposed to ABA or water stress. Exposure to ABA in the culture medium increased the callus ABA levels greatly but a mannitol-induced water stress had only a small effect on ABA levels. Regenerable callus exposed to 0.1 m M ABA also produced mRNA that hybridized on a Northern blot with a globulin- 1 gene ( Glb1) probe. When both Type I and Type II regenerable cultured tissues were exposed to regeneration medium without ABA or mannitol, several GLB1 antibody immunoreactive proteins were produced. These proteins were not detected in regenerated plants nor in non-regenerable callus treated with ABA. These results suggest that: (1) at least for expression of Glb1, somatic embryogenesis is similar to zygotic embryogenesis, (2) there may be a regulatory role for auxin in the processing of Glb1-encoded polypeptides since fewer are seen when dicamba is present in the medium, (3) ABA has a role in somatic embryogenesis, and (4) regenerability of a maize callus culture may be assessed by treating the cultured tissue with 0.1 m M ABA to determine if GLB1 proteins are induced.     

Precociously germinating somatic embryos of Vitis vinifera have lower ABA and IAA levels than their germinating zygotic counterparts

Somatic embryos of Vitis vinifera (cv. Grenache noir) develop normally up to the torpedo stage, but they germinate precociously and form viable plantlets with very low frequency. Because a peak in abscisic acid (ABA) in mid‐embryogenesis could be one factor preventing precocious germination during normal seed development, we followed the development of ABA content concurrent with that of the somatic embryos. Additionally, we measured changes in indoleacetic acid (IAA) levels. We also compared the levels of both hormones during precocious germination of somatic embryos and during normal germination of their zygotic counterparts. Somatic embryos were able to accumulate ABA and IAA throughout their development but no peak in ABA concentration was detected during embryogenesis. This suggests that the switch from mid‐ to late‐embryogenesis is not triggered. Furthermore, during precocious germination, i.e. from the torpedo stage onwards, the concentrations of ABA and IAA in somatic embryos were much lower than during normal germination of zygotic embryos. Thus, it is likely that when precocious germination occurs, grape somatic embryos do not accumulate ABA and/or IAA in sufficient concentrations to support normal plantlet development. Therefore, for grape somatic embryos we propose that prevention of precocious germination, i.e. triggering late‐embryogenesis, is attainable by an ABA treatment followed by slow desiccation, as already shown for conifer somatic embryos. Our results also suggest that the role of ABA and IAA for improving normal germination after imposed quiescence should be investigated.     

A carrot G-box binding factor-type basic region/leucine zipper factor DcBZ1 is involved in abscisic acid signal transduction in somatic embryogenesis.

Carrot (Daucus carota) somatic embryogenesis has been extensively used as an experimental system for studying embryogenesis. In maturing zygotic embryos, abscisic acid (ABA) is involved in acquisition of desiccation tolerance and dormancy. On the other hand, somatic embryos contain low levels of endogenous ABA and show desiccation intolerance and lack dormancy, but tolerance and dormancy can be induced by exogenous application of ABA. In ABA-treated carrot embryos, some ABA-inducible genes are expressed. We isolated the Daucus carota bZIP1 (DcBZ1) gene encoding a G-box binding factor-type basic region/leucine zipper (GBF-type bZIP) factor from carrot somatic embryos. The expression of DcBZ1 was detected in embryogenic cells, non-embryogenic cells, somatic embryos, developing seeds, seedlings, and true leaves. Notably, higher expression was detected in embryogenic cells, true leaves, and seedlings. The expression of DcBZ1 increased in seedlings and true leaves after ABA treatment, whereas expression was not affected by differences in light conditions. During the development of zygotic and somatic embryos, increased expression of DcBZ1 was commonly detected in the later phase of development. The recombinant DcBZ1 protein showed specific binding activity to the two ABA-responsive element-like motifs (motif X and motif Y) in the promoter region of the carrot ABA-inducible gene according to results from an electrophoretic mobility shift assay. Our findings suggest that the carrot GBF-type bZIP factor, DcBZ1, is involved in ABA signal transduction in embryogenesis and other vegetative tissues.     

植物激素对体细胞胚胎发生的诱导与调节

以作者自己的工作为背景,结合国内外近几年的有关报道,综述了几种外源和内源激素对植物体细胞胚胎发生的诱导与调节作用。外源生长素和细胞分裂素是诱导离体培养细胞分化与增殖所必需的,2,4-D是诱导胚性愈伤组织的重要激素。在体细胞胚胎发生中内源激素含量和代谢的平衡起着关键的作用,而且外源和内源激素对诱导体细胞胚胎发生起相互调节作用。ABA在提高体细胞胚胎发生频率和质量上具有重要作用,同时,外源与内源ABA对体细胞胚胎发生起相互促进作用。本文还较为深入地讨论了这些激素诱导体细胞胚胎发生的可能作用机制。 Abstract:The paper summarizes the induced and regulatory effects of a few exogenous and endogenous hormones in plant somatic embryogenesis by our studies and related international reports.The exogenous auxin and cytokinin are necessary to induced differentiation and proliferation of cells of culture in vitro.2,4-D is an important hormone of induced embryogenic calluses.The contents and the metabolic balances of endogenous hormones have key effects for somatic embryogenesis.In addition,the exogenous and endogenous hormones have mutual regulatory effects for somatic embryogenesis.ABA has an important effect to improving the frequency and quality of somatic embryogenesis.Meanwhile,the exogenous and endogenous ABA have mutual promoted effects for somatic embryogenesis.The paper discusses possible mechanism of hormones-induced somatic embryogenesis in a deep-going way.