紫稻(Oryza sativa L.)线粒体ATP酶atp9基因转录本RNA编辑

紫稻（Oryza sativa L．）细胞质雄性不育系是本实验室新构建的新型细胞质雄性不育系。本研究使用PCR、RT—PCR等技术,得到了紫稻不育系（樱香A）及其保持系（樱香B）线粒体atp9基因的基因组序列和cDNA序列。通过对这些序列的分析发现：樱香A atp9 cDNA序列中,没有发生RNA编辑;而樱香B atp 9cDNA序列中有2个编辑位点,在樱香BcDNA序列2个编辑位点中,223位点由C替换为T,导致原来编码精氨酸密码子成为终止密码子,保证atp9 mRNA编码一个“正常长度”的ATP9多肽。而由于没有终止密码子,樱香AmRNA就不能翻译成正常的多肽。上述研究表明,RNA编辑在生成正常的ATP9多肽的过程中发挥了重要作用,同时也说明RNA编辑可能与细胞质雄性不育相关。     

苎麻atp6和atp9基因的克隆表达及与细胞质雄性不育的相关性

摘要: 根据GenBank报道的双子叶植物线粒体atp6和atp9基因编码区保守序列设计简并引物, 通过PCR技术从苎麻细胞质雄性不育系、保持系和恢复系(简称“三系”) mtDNA中扩增目的基因片段, 发现所得序列开放阅读框虽不完整, 但与GenBank报道的其他植物线粒体atp6和atp9基因同源性分别高于94%和85%。采用DNA Walking步移法分别从3′端和5′端扩增两个基因片段的未知侧翼序列, 分离出完整的苎麻线粒体atp6和atp9基因, 包含了完整的开放阅读框。其中“三系”的atp6基因在mtDNA水平、转录和翻译调控水平、蛋白质水平上均无差异。不育系atp9基因在编码区3′端与保持系和恢复系相比存在若干个碱基的差异和缺失; RT-PCR分析还表明, 不育系atp9基因在现蕾期和盛花期的表达量很高。推测不育系atp9基因的结构变异和/或异常表达与苎麻细胞质雄性不育(CMS)的关系密切。     

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水稻线粒体atp6基因转录本的编辑位点研究

以红莲(HL)型水稻细胞质雄性不育系A、保持系B及杂种一代F1为材料,首次比较研究了红莲型水稻线粒体atp6基因转录本的编辑位点及各位点的编辑频率.结果表明atp6基因的转录本有18个编辑位点,其中有15个发生在密码子的第一和第二位点上,这些位点的编辑最终会导致氨基酸种类的变化.18个编辑位点在A、B和F1中没有差异,但各位点的编辑频率在引入了核恢复基因的条件下发生了较大的变化,完全编辑的比例增加.这些结果首次证明HL型细胞质雄性不育与线粒体atp6转录本的编辑有一定相关性,编辑不充分的转录产物最终会干扰线粒体功能的正常发挥.     

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。     

玉米不育系及其保持系线粒体atp6基因转录本编辑位点研究

以玉米同核异质细胞质雄性不育系T黄早四、C黄早四、S黄早四以及保持系N黄早四为材料, 比较研究了供试材料小孢子发育到单核期的线粒体atp6基因转录本保守区域的编辑位点。结果表明, DNA序列在T、C、S 3种胞质中完全一致, 与N胞质相比除在27、28核苷酸处不同外, 其余均一致, 而各胞质cDNA序列却不尽相同。DNA和cDNA序列比较显示: atp6基因转录本保守区域内, N、S胞质中均存在19个编辑位点, T胞质存在22个, C胞质存在20个, 它们相同的编辑位点有18个。大多数编辑位点都发生在密码子的第一、二位点上, 可改变氨基酸的种类。18个相同的编辑位点大都为完全编辑, 其中第1位点在各胞质中为部分编辑, 第19位点除在N胞质中为完全编辑外其余胞质都为部分编辑。而各胞质特有编辑位点均以部分编辑的形式出现。由此可见, 在玉米中atp6基因RNA编辑不仅具有序列特异性, 同时还受到胞质背景的影响。通过分析还可看出, 编辑的C残基前一个碱基多为嘧啶类碱基, 编码氨基酸Ser和Pro的密码子较其他类的密码子更易受到编辑, 且植物RNA的编辑有着改变蛋白质疏水性、增加物种间保守性的倾向。     

水稻线粒体atpA基因的克隆及其与细胞质雄性不育的关系

本研究以水稻BT型细胞质雄性不育系秋光和相应的保持系秋光为材料，提取线粒体DNA，用限制性内切酶完全酶解，以玉米线粒体atpA基因和波菜叶绿体atpA基因作为探针，进行分子杂交，将保持系线粒体atpA基因定位在3.5kb的Bam HI酶切片段上，并且以pBR322为载体，克隆了这一片段，另外，在Bam HI完全酶解普带的杂交结果中，不育系线粒体基因组中有两条阳性杂交带，分别是3.5kb和2.9kb，而保持系线粒体基因组中只有3.5kb一条阳性杂交带，因而认为水稻不育系线粒体基因组中可能有两个atpA基因拷贝，而相应的保持系线粒体基因组中只有一个atpA基因拷贝。     

水稻线粒体atpA基因的克隆及其与细胞质雄性不育的关系

本研究以水稻BT型细胞质雄性不育系秋光和相应的保持系秋光为材料,提取线粒体DNA,用限制性内切酶完全酶解,以玉米线粒体atpA基因和波菜叶绿体atpA基因作为探针,进行分子杂交,将保持系线粒体atpA基因定位在3.5kb的Bam HI酶切片段上,并且以pBR322为载体,克隆了这一片段,另外,在Bam HI完全酶解普带的杂交结果中,不育系线粒体基因组中有两条阳性杂交带,分别是3.5kb和2.9kb,而保持系线粒体基因组中只有3.5kb一条阳性杂交带,因而认为水稻不育系线粒体基因组中可能有两个atpA基因拷贝,而相应的保持系线粒体基因组中只有一个atpA基因拷贝。     

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.     

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。     

The effects of cytoplasmic male sterility on cytonuclear disequilibria in hybrid zones

Male sterility is studied in hybrid zones by different measures of cytonuclear disequilibria, D, D₁, D₂, and D₃. Of particular interest are the dynamics of disequilibria as the system evolves to equilibrium. Our first model, the hybrid swarm model, yields equilibrium results identical to those observed in a model with random mating. In our second model of a hybrid zone, predictions of the sign pattern of disequilibrium values can be made based on migration values. A characteristic sign pattern may help to distinguish cytoplasmic male sterility (CMS) from other mechanisms of selection. Our simple CMS model with migration is successfully fit to cytonuclear data on a hybrid population of cottonwoods.     

Mitochondrial gene expression and cytoplasmic male sterility in sorghum

Variation in sorghum mitochondrial translation products has enabled fertile (Kafir) cytoplasm to be distinguished from Milo cytoplasmic male sterile cytoplasm and from three alternative sources of cytoplasmic male sterile cytoplasm. Mitochondria from Milo cytoplasm synthesised a 65 000 mol. wt. polypeptide which was not synthesised by those from Kafir cytoplasm. In the cytoplasmic male sterile combination of Kafir nucleus in Milo cytoplasm synthesis of this polypeptide was dramatically increased. Mitochondria from two cytoplasmic male sterile lines (Kafir nucleus in IS1112 cytoplasm and Yellow Feterita nucleus in M35-1 cytoplasm) did not synthesise the 65 000 mol. wt. polypeptide but synthesised additional high molecular weight polypeptides (from 54 000 to 82 000 mol. wt.), the major one being 82 000. Mitochondria from cytoplasm IS1112 were also distinguished by synthesis of an additional 12 000 mol. wt. polypeptide. Mitochondria from the cytoplasmic male sterile line Martin nucleus in 9E cytoplasm synthesised an additional 42 000 mol. wt. polypeptide but did not synthesise a 38 000 mol. wt. polypeptide detected in all other cytoplasms. Immunoprecipitation of mitochondrial translation products with antiserum raised against subunit I of yeast cytochrome oxidase tentatively identified the 38 000 mol. wt. polypeptide as subunit I of sorghum cytochrome oxidase. The 42 000 mol. wt. polypeptide was also immuno-precipitated by this antiserum and thus is probably an altered form of cytochrome oxidase subunit I.Analysis of native mitochondrial DNA by agarose gel electrophoresis revealed the presence of two plasmid-like DNA species of molecular weight 5.3 and 5.7 kb in the cytoplasmic male sterile lines Kafir nucleus in cytoplasm IS1112 and Yellow Feterita nucleus in M35-1 cytoplasm. Thus there is a positive correlation between the synthesis of the 82 000 mol. wt. polypeptide and the presence of the additional DNA species.     

高等植物胞质雄性不育及育性恢复的分子生物学研究进展

综述了几种植物胞质雄性不育的分子机理研究进展,着重介绍了与细胞质雄性不育相关的线粒体连锁位点的分析及育性恢复的几种假说,并对今后的研究进行了讨论。     

萝卜CMS不育系与保持系小孢子发生的细胞学研究

研究了萝卜胞质雄性不育系A2、A4及其相应保持系B2、B4的小孢子发生与花药壁发育的细胞学特征.结果表明,不育系A2的绒毡层细胞在四分体时期出现异常,小液泡增多,至单核期汇合形成大液泡,绒毡层细胞异常膨大;小孢子外壁染色浅,细胞壁受到破坏,最后与绒毡层一同降解.不育系A4在减数分裂期即表现出异常,绒毡层异常肥大;花药发育后期,小孢子外壁亦染色较浅;绒毡层细胞融合形成细胞团块侵入药室挤压小孢子,两者一同降解.     

Molecular basis of cytoplasmic male sterility and fertility restoration in rice

Cytoplasmic male sterility (CMS) is a maternally inherited trait that causes dysfunctions in pollen and anther development. CMS is caused by the interaction between nuclear and mitochondrial genomes. A product of a CMS-causing gene encoded by the mitochondrial genome affects mitochondrial function and the regulation of nuclear genes, leading to male sterility. In contrast, the RESTORER OF FERTILITY gene (Rf gene) in the nuclear genome suppresses the expression of the CMS-causing gene and restores male fertility. An alloplasmic CMS line is often bred as a result of nuclear substitution, which causes the removal of functional Rf genes and allows the expression of a CMS-causing gene in mitochondria. The CMS/Rf system is an excellent model for understanding the genetic interactions and cooperative functions of mitochondrial and nuclear genomes in plants, and is also an agronomically important trait for hybrid seed production. In this review article, pollen and anther phenotypes of CMS, CMS-associated mitochondrial genes, Rf genes, and the mechanism that causes pollen abortion and its agronomical application for rice are described.     

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。     

Variable presence of the 1.94kb mitochondrial plasmid in maize S cytoplasm and its relationship to cytoplasmic male sterility

Mitochondrial DNA (mtDNA) was isolated from over 100 different maize nucleo-cytoplasmic combinations. DNA preparations were assayed for the presence of the 1.94kb mitochondrial plasmid by agarose gel electrophoresis and hybridization to a recombinant clone of the plasmid. The plasmid was present in all tested inbreds which carried N, male fertile, cytoplasm or the cytoplasmically male sterile (cms) groups,cms-T andcms-C. However, members of thecms-S group differed with respect to the presence of the plasmid. Cytoplasms I, J and S possessed the plasmid, whereas cytoplasms B, CA, D, G, H, IA, ME, ML, PS, RD and VG did not.Cms-S group lines which had spontaneously reverted to fertility (nuclear and cytoplasmic revertants) did not exhibit a concomitant change in 1.94kb plasmid levels, although all such lines showed the previously reported alteration in levels of the linear mtDNAs, S1 and S2. The presence or absence of the plasmid was not correlated with (i) frequency of reversion to fertility, (ii) the degree of male sterility expressed, (iii) the presence or absence of standard nuclear restorer to fertility genes and (iv) nuclear genotype. Latin American races carrying RU cytoplasm possessed the plasmid, as did sweet corn varieties. The relevance of the data tocms and evolution of thecms-S group is discussed.     

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.     

植物胞质雄性不育及育性恢复的分子机制研究进展(综述)

本文从与雄性不育有关的线粒体基因引起雄性不育的机理、雄性不育育性恢复机制以及育性恢复基因的克隆等方面,介绍国内外对植物细胞质雄性不育分子机理的研究进展,并对今后的研究进行讨论。