植物线粒体与细胞质雄性不育研究进展

本文从能量代谢与植物细胞质雄性不育(CMS)、线粒体的结构和数量与CMS、线粒体DNA多态性与CMS、线粒体基因转录与CMS、线粒体多肽差异与CMS几个方面介绍了植物线粒体与CMS的关系。并介绍了与CMS相关的线粒体基因研究进展并对CMS形成的分子机制进行了探讨。     

植物线粒体与细胞质雄性不育研究进展

本文从能量代谢与植物细胞质雄性不育(CMS)、线粒体的结构和数量与CMS、线粒体DNA多态性与CMS、线粒体基因转录与CMS、线粒体多肽差异与CMS几个方面介绍了植物线粒体与CMS的关系。并介绍了与CMS相关的线粒体基因研究进展并对CMS形成的分子机制进行了探讨。     

红莲型细胞质雄性不育性与线粒体渗透性转换

以水稻红莲型细胞质雄性不育(HL-CMS)的不育系粤泰A(YTA)、保持系粤泰B(YTB)以及杂种F1代红莲2号(HL2)的黄化苗为材料,研究了在不同pH及离子强度下线粒体渗透性转换(MPT)的发生及其差异。结果表明,YTA、YTB和HL2间MPT的发生均存在差别,不育系YTA线粒体渗透性转换孔(PTP)的开启与关闭对pH及离子强度的变化较保持系YTB和HL2敏感。HL2与YTA虽然具有相同的细胞质来源,但两者之间PTP及MPT的特性明显不同,前者MPT的变化与具有正常生理功能的YTB线粒体的PTP和MPT的发生特点与特性相似。这些说明红莲型水稻细胞质雄性不育的发生可能与其MPT的发生有关。     

高等植物细胞质雄性不育分子机理的研究进展

从线粒体DNA、叶绿体DNA和线粒体质粒DNA方面较详细地阐述了高等植物细胞质雄性不育的分子机理及最新进展;探讨了细胞核DNA和细胞质DNA之间的相互关系。     

细胞质雄性不育水稻线粒体基因组的RFLP分析

利用RFLP技术,比较研究了在农业生产上广泛应用的9种细胞质雄性不育体系的线粒体基因组,结果表明：1）9种水稻雄性不育细胞质的遗传相似性变化范围为0．615～1．000。所有配子体雄性不育细胞质的遗传相似性变化范围为0．6431．000,其中QXA,DY1A和YM15A这3种细胞质的遗传相似性为1．000。所有孢子体雄性不育细胞质的遗传相似性为1．000,2）在配子体细胞质雄性不育水稻中,用3个探针（atpa,atp9＋nad6,cox2）与2种内切酶（HindⅢ,BamHⅠ）的组合未发现不育系与保持系之间的多态性,但在探针atp6,cob,和had2的杂交带型中找到了不育系和保持系之间的一些差异。YTA和YTB在5个探针．内切酶组合（atp61HindⅢ,coblHindⅢ,atp61BamHⅠ,coblBamHⅠ,nad21BamHⅠ）中存在差异。3种细胞质（QX,SJ,DY1）的不育系和保持系之间的差异是相同的,都出现在atp6／HindⅢ,atp6／BamHⅠ,cob／BamHⅠ等3个组合中。YM15A和YM15B在4个组合（atp6／HindⅢ,atp6／BamHⅠ,cob／BamHⅠ,nad2／BamHⅠ）中存在差异。LYA和LYB的差异出现在cob／HindⅢ,cob／BamHⅠ,nad2／BamHⅠ这3个组合中;3）在孢子体细胞质雄性不育水稻中,所有不育系的带型是一样的,所有保持系的带型也一样。不育系和保持系的差异出现在atp6／HindⅢ,cob／HindⅢ,atp6／EcoR,Ⅰcob／EcoRⅠ,cox1／EcoRⅠ,atp6／BamHⅠ,cob／BamHⅠ,cox1／BamHⅠ,cox2／BamHⅠ等9个组合中。这些结果在分子水平上揭示了9种雄性不育细胞质的线粒体基因组存在结构多样性,并为其细胞质雄性不育分子机理的研究打下了基础。     

甘蓝型油菜细胞质雄性不育系301A线粒体不育基因片段分析

提取细胞质雄性不育系301A、212A和'陕3A'及其共同保持系'中双2号'线粒体DNA,根据已报道的Polima油菜细胞质雄性不育相关基因orf224序列设计引物,对3种不同来源的线粒体DNA PCR产物进行分析.结果显示,这3种甘蓝型油菜细胞质雄性不育材料所获得片段序列完全一致,且与已报道的Polima油菜线粒体中细胞质雄性不育相关基因orf224序列完全相同.研究表明,不育材料301A从分子角度讲属于Polima系统,不育系301A、212A和'陕3A'线粒体中与细胞质雄性不育相关线粒体基因片段orf224具有高度同源性.     

小麦K型及V型细胞质雄性不育系线粒体DNA的比较分析

采用ＲＦＬＰ和ＲＡＰＤ技术对具有相同核遗传背景的小麦Ｋ型不育系Ｋ１４９Ａ,Ｖ型不育系Ｖ１４９Ａ及相应保持系１４９Ｂ的线粒体ＤＮＡ进行了比较分析。结果表明它们之间线粒体ＤＮＡ的结构显著不同,ａｔｐＡ,ａｔｐ９,ｃｏｘⅡ,ｃｏｂ等线粒体功能基因有组织结构上的差异。     

玉米S组细胞质雄性不育线粒体R区序列与多型性分析

玉米Ｓ组细胞难性不育（ＣＭＳ）可能与线粒体基因组中的Ｒ区域有关。对不同核背景下唐徐、双２种Ｓ胞质的线粒体ＤＮＡ以Ｒ区特异探针的Ｓｏｕｔｈｅｒｎ分析发现均有６．７ｋｂ、４．５ｋｂ、１．８ｋｂ的３条谱带,分别对应于２种位于线粒体基因组中间的类型和１个线性末端,并且核背景对这３种不同形式的Ｒ区域的量有影响。对Ｍｏ１７和７７核背景下Ｎ、Ｔ、Ｃ４种胞质１７种材料的玉米线粒体基因组中Ｒ区的Ｓｏｕｔｈｅｒｎ分析     

Variation of female frequency and cytoplasmic male-sterility gene frequency among natural gynodioecious populations of wild radish (Raphanus sativus L.)

In gynodioecious plant populations, sex determination often involves both cytoplasmic male-sterility (CMS) genes and specific nuclear genes that restore male function. How gynodioecy is maintained under the joint dynamics of CMS and restorer genes remains controversial. Although many theoretical models deal with interactions between CMS genes and restorer genes with sexual phenotypes and predict changes in their frequencies, it is difficult to observe the frequencies because no molecular markers have been established for either CMS or restorer genes in well-studied gynodioecious plants. This is the first report of the frequency of a CMS gene determined using a molecular marker in natural populations of a gynodioecious plant. Using a set of CMS gene-specific polymerase chain reaction primers, we compared female and CMS gene frequencies in 18 natural populations of Raphanus sativus. Female frequency was relatively low, ranging from 0 to 0.21. In contrast, the CMS gene frequency was highly variable among populations, ranging from 0 to 1. Estimated restorer gene frequency seemed less variable than observed CMS gene frequency, probably due to higher gene flow than in the CMS gene. Genetic drift may play a role in maintaining high variability of the CMS gene, although other possibilities are not excluded.     

Nitrate assimilation-its regulation and relationship to reduced nitrogen in higher plants

The regulation of nitrate assimilation in higher plants is reviewed in relation to the availability and accumulation of reduced nitrogen. The effects of light on these processes are also considered.     

Mitochondrial genome organization and cytoplasmic male sterility in plants

Plant mitochondrial genomes are much larger and more complex than those of other eukaryotic organisms. They contain a very active recombination system and have a multipartite genome organization with a master circle resolving into two or more subgenomic circles by recombination through repeated sequences. Their protein coding capacity is very low and is comparable to that of animal and fungal systems. Several subunits of mitochondrial functional complexes, a complete set of tRNAs and 26S, 18S and 5S rRNAs are coded by the plant mitochondrial genome. The protein coding genes contain group II introns. The organelle genome contains stretches of DNA sequences homologous to chloroplast DNA. It also contains actively transcribed DNA sequences having open reading frames. Plasmid like DNA molecules are found in mitochondria of some plants Cytoplasmic male sterility in plants, characterized by failure to produce functional pollen grains, is a maternally inherited trait. This phenomenon has been found in many species of plants and is conveniently used for hybrid plant production. The genetic determinants for cytoplasmic male sterility reside in the mitochondrial genome. Some species of plants exhibit more than one type of cytoplasmic male sterility. Several nuclear genes are known to control expression of cytoplasmic male sterility. Different cytoplasmic male sterility types are distinguished by their specific nuclear genes(rfs) which restore pollen fertility. Cytoplasmic male sterility types are also characterized by mitochondrial DNA restriction fragment length polymorphism patterns, variations in mitochondrial RNAs, differences in protein synthetic profiles, differences in sensitivity to fungal toxins and insecticides, presence of plasmid DNAs or RNAs and also presence of certain unique sequences in the genome. Recently nuclear male sterility systems based on (i) over expression of agrobacterialrol C gene and (ii) anther specific expression of an RNase gene have been developed in tobacco andBrassica by genetic engineering methods.     

Regulation of nitrate reductase activity in higher plants

Nitrate reductase is one of the most important enzymes in the assimilation of exogenous nitrate—the predominant form of nitrogen available to green plants growing in soil. Activity of this enzyme in plants gives a good estimate of the nitrogen status of the plant and is very often correlated with growth and yield. Although it is difficult to explain the physiological significance and the mechanism of effects of several factors on the enzyme activity, in some cases suitable postulates have been advanced. In general, the enzyme activity in a plant tissue is a balance between its relative rates of synthesis/degradation and activation/inactivation. Factors may affect the overall activity by interfering with either of these processes.     

Is cytoplasmic pH involved in the regulation of cell cycle in plants?

Modifications of cytoplasmic pH has biological significance in animal and plant cell development. Many observations suggest an important function of cytopiasmic pH in mitotic signalling in animal ceils. In Bidens pilosa cultivated under white light, acidification of cytoplasm, observed after mechanical trauma, is associated with an inhibition of DNA synthesis and a decrease in mitotic frequency. In contrast, in Bidens pilosa cultivated under blue light, mechanical stimulation induces an increase of cytoplasmic pH and stimulation of DNA duplication and mitotic activity. A correlation has been established between transient variations of cytoplasmic pH and rapid modification in cell development. The critical role of cytoplasmic pH in the regulation of the cell cycle in plants is discussed.     

高等植物赤霉素2-氧化酶基因的克隆、表达及其调控

赤霉素(GA)是一类重要的植物激素,对高等植物整个生命周期的生长发育起关键作用。调控赤霉素生物合成和代谢途径中的关键酶基因的表达可以控制植物体内赤霉素的含量。GA2-氧化酶是调节赤霉素合成和代谢的关键酶之一,使活性GA失活。本文主要对GA2-氧化酶基因的克隆、表达调控及其在植物基因工程中的应用等方面进行综述,为通过基因工程技术调控植物体内活性赤霉素的含量从而得到改良品种提供思路。     

Messenger DNA in higher plants

Evidence is presented that, as in animal and human cells, plant cells can release a newly-synthesized DNA which can freely circulate in the plants. This DNA enters cells and their nuclei where it may be integrated and be expressed so acting, apparently, as a messenger-DNA.