新型小麦胞质不育系花粉败育的细胞学观察

观察了１种新型小麦细胞质雄性不育素（ＣＭＳ）－（野生二粒小麦）中国春ＣＭＳ花药和花粉败育的细胞学过程,结果表明;（１）不育系在小孢子发育至单核晚期以前,除了雄蕊心皮化发生率（３７．２％）较高外,其花药和花粉发育绝大多数与同核保持系相似,是正常的,仅少量表现异常而导致败育,异常现象主要有：雄蕊心皮化。药室合并,药壁组织喙状突起,绒毡层异常,小孢子母细胞粘连,减数分裂异常,小孢子异常等。（２）不育系花     

长春蒲公英雄性不育株形态学观察与败育细胞学研究

在长春蒲公英(Taraxacum junpeianum Kitam.)株群中发现雄性不育现象,为研究其败育机理及特点,探寻其不育基因,采用形态观察法、石蜡切片技术和染色体压片法,对长春蒲公英野生型及其雄性不育株的花药发育过程和花粉母细胞减数分裂过程进行了观察。结果表明:(1)长春蒲公英雄性不育株花药中部发红、干瘪、无花粉散出。与野生型比较,雄性不育株雄蕊更短,子房更窄,种子形态更加狭长;(2)长春蒲公英雄性不育株败育时期为四分体到单核小孢子前期,败育方式为小孢子自身异常发育,绒毡层异常分解,互相粘连败育;(3)长春蒲公英雄性不育株花粉母细胞减数分裂二分体时期出现落后微核,随后产生极少四分体,并且四分体产生大量染色体桥,小孢子营养物质流失,彻底败育。因此,长春蒲公英雄性不育株败育彻底、稳定,并且有种的特点。小孢子自身异常发育和绒毡层异常分解是导致败育的主要原因。     

雄性不育与三系配套

雄性不育雄性不育是指植物的雌性(雌蕊)正常,雄性(雄蕊)不正常,不能产生花粉或花粉败育的现象.雄性不育现象在植物中普遍存在,玉米、高粱、小麦、水稻、洋葱等作物中都有发现.玉米中有一种雄性不育的变异,植株在开花抽穗期,雄穗上的花药不能显示出来,整个植株不能开花散粉,其雌蕊的发育正常,能接受另一植株的花粉而结实.又如我国科技工作者发现的雄性败育的野生稻等.     

不结球白菜雄蕊心皮化雄性不育系HGMSⅡ特性研究

对不结球白菜雄蕊心皮化雄性不育系HGMS和HGMSⅡ进行花器形态比较、同功酶分析及结实性研究.结果表明:HGMSⅡ较好地保留了HGMS花瓣萼片化、雄蕊心皮化鲜明特征,而且花瓣EST和POD同功酶酶带与萼片酶带基本相同,心皮化器官EST和POD同功酶酶带与雌蕊酶带相同.与完全雄蕊心皮化的HGMS相比,HGMSⅡ雄蕊心皮化突变主要发生在花药部位,导致花药丧失了产生花粉的能力,从而保留了HGMS不育性稳定、彻底的优良特性.与HGMS相比,HGMSⅡ开花习性明显改善,柱头表面花粉明显增多,雌蕊发育基本正常,单株平均籽粒产量达到8.96 g,较HGMS增加了7.17 g,增幅达401%,结实性得到了显著提高.     

封面说明

正植物雄性不育(Male sterility)通常是指雄蕊不能产生正常有功能的花粉,但雌蕊发育正常可接受其他花粉而受精结实。植物雄性不育不仅是杂种优势利用的重要工具,也是研究植物生殖发育的关键材料。随着高通量测序技术的发展与完善,利用高通量测序技术从转录水平分析败育发生的机理,为植物生殖发育及雄蕊败育机理的解析提供丰富的数据信息。目前在水稻(Oryza sativa)、小麦(Triticum aestivum)、玉米(Zeamays)、棉花(Gossypium hirsutum)等20多个物种中,包括细胞质雄性不育(Cytoplasmic male sterility、CMS)、化学诱导雄性不育(Induced male sterility)、     

起源于组织培养的籼稻雄性不育体细胞无性系变异

IR8及IR54的成熟种子与幼穗培养在MS培养基,蔗糖6％附加生长刺激素及其它成分的条件下,在再分化植株第一代(R_1)中各发现了1株雄性不育突变(其中来自IR54的1株为育性嵌合体)。在IR24及IR54体细胞无性系第二代(R_2)各发现1个株系分离出雄性不育与育性正常两类植株。上述雄性不育有花粉败育与无花粉型两类。IR24对无花粉型的雄性不育(来自IR54)为半恢复。F_1及R_2代的育性分离完全符合15/16∶1/16的模式,表明雄性不育为两对独立的核基因所控制。通常雄性不育是通过杂交(包括远缘与品种间)理化诱变或自发突变产生的。最近在烟草上通过原生质体融合也获得了雄性不育。但从体细胞培养的无性系及其后代中获得雄性不育的突变,本研究乃属首次。     

高通量转录组测序技术在植物雄性不育研究中的应用

植物雄性不育是指植物雄蕊发育受阻不能产生正常有功能花粉的现象。植物雄性不育不仅是生殖生理研究的宝贵材料,也是植物杂种优势利用的重要工具。由于高通量转录组测序技术几乎可以检测细胞内所有mRNA及非编码RNA的信息,已被广泛应用于生命科学研究的各项领域。在植物雄性不育相关研究中,高通量转录组测序技术在不同物种、不同败育类型中的应用已有报道,这为研究者在转录组水平综合了解植物雄性不育的分子机制及代谢网络提供了帮助。本文从测序文库构建策略、差异表达基因、非编码RNA的功能特征等方面综述了高通量转录组测序在植物雄性不育机理方面的研究进展,并探讨了转录组测序技术在花粉败育机制解析及育性相关基因定位中的应用价值,以期为植物雄性不育的相关研究提供参考。     

水稻野败型雄性不育系花粉败育的解剖学和细胞学观察

关于植物雄性不育的小孢子发生的组织学和细胞学研究,过去曾有过不少报道。Laser和Lersten曾对自1925年起至1972年4月1日止的文献作了综合性的评论。在该文的表1中列举了曾研究过的植物种类,均未提及水稻。近年来,国内外也有人对水稻雄性不育的小孢子发生过程进行了细胞学的观察。我室自1975年起,除观察水稻雄性不育的小孢子发生过程外,主要对花药的毡绒层及花丝组织进行了解剖观察,以探索其花粉败育的原因。据我们的观察结果,不同类型的水稻雄性不育系,其花粉的败育过程也不完全相同。因此,需要对不同类型的水稻雄性不育系的花粉败育过程分别加以研究。本文主要报道对野生稻花粉败育型雄性不育系进行观察的结果。     

无花瓣油菜雄蕊心皮化突变体细胞学观察及基因表达分析

油菜是我国重要的油料作物,油菜花器官具有典型的十字花科特点,无花瓣油菜在花期不存在花冠层,这种特点有助于提高油菜产量,预防茵核病的传播。雄蕊心皮化是指花器官的雄蕊结构被具有类似于雌蕊结构的器官代替,这不仅造成了花器官结构的变化也导致了雄性不育。本文通过对无花瓣油菜雄蕊心皮化突变不育分离群体中的雄性可育株和不育株的比较研究,发现心皮化现象是由遗传因素引起的。细胞学观察发现,雄蕊心皮化在花器官发育的早期就已经产生,心皮化的雄蕊中着生类似于胚珠的结构,其顶端细胞的形态和排列方式也与雌蕊柱头相似。花发育相关基因的表达分析表明,B组基因彳丹在不育株3轮花器中的表达都比可育株低,特别是在第二轮花器官中这种差异最为突出。而A组基因AP1在不育株第二轮花器官中的表达量较可育株高。c组基因AGL8、SHPI、SHP2、NAP在不育株心皮化的第二轮花器官中表达都较可育株中高。     

甘蓝型油菜雄性不育系160S育性转换与利用

以甘蓝型油菜雄性不育系160S为试验材料,分别在自然栽种和人工控温条件下对其花器官形态变化、花粉育性转换和杂种优势等进行了初步研究,以探讨植物温敏雄性不育的发生机制。结果表明:环境温度对160S的花器官形态及育性转换具有明显的作用,高温可使花瓣变小,雄蕊退化,花粉活力、角粒数与自交有效结角率降低,表现为低温可育、高温不育,育性变化趋势表现为完全可育-半不育-彻底败育。160S恢复源广泛,且具有较好的配合力和杂种优势,为利用两系法生产油菜杂交种提供了一个较好的途径。     

Modifications of Mitochondrial DNA Cause Changes in Floral Development in Homeotic-like Mutants of Tobacco

To investigate the influence of mitochondrial genes on stamen development of higher plants, protoplasts from three different, male-sterile tobacco cultivars were fused. The fused cells were cultured individually into calli, from which plants were regenerated. Cybrid plants were obtained that exhibited flowers with recombined biparental male-sterile morphology and with novel male-sterile stamens that differed from any types from sexual or somatic hybridizations described previously. The male-sterile morphologies of these cybrids and their parents support the hypothesis that nuclear-mitochondrial interaction occurs at several stages in tobacco floral development and that several mitochondrial genes are necessary for normal stamen and corolla development. Analysis by restriction endonuclease digestion of mitochondrial DNA of male-sterile cybrids and their parents revealed that the mitochondrial DNA of male-sterile cybrids with parental floral morphology was unchanged when compared with parental mitochondrial DNA. Cybrids that were morphologically similar to one parent's male-sterile phenotype had mitochondrial DNA almost identical to that parent, whereas cybrids with recombined biparental or novel male-sterile phenotypes contained mitochondrial DNA different from both male-sterile parents and from each other. A set of mitochondrial DNA fragments could be correlated with split corollas, a feature found in several tobacco male-sterile cultivars. DNA gel blot analysis using a number of mitochondrial genes confirmed the conclusions based on ethidium bromide staining of mitochondrial DNA restriction digests.     

Defective cell proliferation in the floral meristem of alloplasmic plants of Nicotiana tabacum leads to abnormal floral organ development and male sterility

Flowers of an alloplasmic male-sterile tobacco line, comprised of the nuclear genome of Nicotiana tabacum and the cytoplasm of Nicotiana repanda, develop short, poorly-pigmented petals and abnormal sterile stamens that often are fused with the carpel wall. The development of flower organ primordia and establishment of boundaries between the different zones in the floral meristem were investigated by performing expression analysis of the tobacco orthologs of the organ identity genes GLO, AG and DEF. These studies support the conclusion that boundary formation was impaired between the organs produced in whorls 3 and 4 resulting in partial fusions between anthers and carpels. According to the investigations cell divisions and floral meristem size in the alloplasmic line were drastically reduced in comparison with the male-fertile tobacco line. The reduction in cell divisions leads to a discrepancy between cell number and cell determination at the stage when petal and stamen primordia should be initiated. At the same stage expression of the homeotic genes was delayed in comparison with the male-fertile line. However, the abnormal organ development was not due to a failure in the spatial expression of the organ identity genes. Instead the aberrant development in the floral organs of whorls 2, 3 and 4 appears to be caused by deficient floral meristem development at an earlier stage. Furthermore, defects in cell proliferation in the floral meristem of the alloplasmic male-sterile line correlates with presence of morphologically modified mitochondria. The putative causes of reduced cell number in the floral meristem and the consequences for floral development are discussed.     

Comparative analysis of stamen polypeptides of a rapeseed cultivar,Regent, a CMS polima line,and temperature-restored male-fertile polima line

Summary Polypeptides were extracted from stamens of a rapeseed (Brassica napus) cultivar, Regent, a near isogenic male-sterile line, Polima-R7 (Pol-R7), and a high-temperature-restored malefertile Pol-R7 (TR) and subsequently separated by two-dimensional isoelectric focusing-polyacrylamide gel electrophoresis under denaturing conditions. Four variable polypeptides with a pI around 6 were observed. Two stamen polypeptides (40000 Da, 38000 Da) were unique to Regent, and the other two (32000 Da, 30000 Da) were unique to the male-sterile Pol-R7. When the male-sterile Pol-R7 was treated with day/night temperatures of 30°/24° C for 7–10 days prior to flowering, both polypeptides unique to Regent reappeared, while the smaller polypeptides disappeared. Temperature-restored male-fertile Pol-R7 (TR) produced fertile pollen, while its short stamen filaments resembled those of the male-sterile Pol-R7. These changes in protein expression may be causally related to the CMS phenotype.     

湖北光周期敏感核不育水稻农垦58S幼穗和花药发育期的蛋白酶活性变化

湖北光周期敏感核不育水稻农垦585的可育与不育株在一次枝梗期的幼穗中可溶性蛋白含量相近。雌雄蕊形成期和花粉母细胞分化期的可有株可溶性蛋白较不育株的分别高21％和12．3％;可有株在花粉二核和三核期亦有较高含量。不育株在雌雄蕊形成期后,酪蛋白酶活性迅速增高,而可有株至二核期才增高。不育株除在二次枝梗期的内肽酶活性略低外,其余阶段酶的活性较高。育性转变时内肽酶类型亦发生变化。可有株有较高的氨肽酶活性．     

三白草科花部发育及其系统学意义

本研究从比较三白草科属间小花个体发育及分析花器官数量变异入手,探寻花器官在发生顺序、数目变化及排列方式等方面的演化趋势,揭示系统发育在个体发育中一定程度重现的事实及属间的进化关系。结果简述如下:首先,雄蕊和心皮发生顺序由中部优先演化到两侧优先。其次,由于远中雄蕊和心皮经历了从发育延迟、生长减缓到最终消失的历程,中部雄蕊和心皮由成对演化为单生。此外,两侧生雄蕊对由各自独立的原基发生演化到共同原基发生或减化为1枚,假银莲花属近中1枚雄蕊原基二裂成1对,蕺菜属3枚心皮发生于一环状共同原基等,都是该科花器官演化的重要事实并可归结为融合、减化和复化的结果。文章根据花器官的演化趋势及过渡类型的剖析,论述了三白草科属间的系统进化关系。     

<Emphasis Type="Italic">Multiple impairments in male reproduction 1 (mimr1)</Emphasis>, a novel male-sterile mutant of <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>, shows several defects in male reproductive development

We have characterized a new male-sterile mutant in Arabidopsis that exhibits conditional sterility but has restored fertility when drought-stressed. This mutant, multiple impairments in male reproduction 1 (mimr1), shows pleiotropic defects in both vegetative and reproductive development. Examination with dissecting and scanning electron microscopes revealed that its pollen grains are not effectively released from the anther locule after dehiscence, and anther differentiation is defective. Growth of the style and stamen filaments are also abnormal. Histological analysis demonstrated that these phenomena are due not only to a noticeably reduced extension of the stamen but also greater elongation of the pistil. Genetic analysis indicated that mimr1 is a single locus recessive nuclear mutant. The mutation can be mapped to a locus strongly linked to a 1200-kb region on Chromosome 3. Meta-analysis of expression patterning presented several candidate genes in that region. No mutants with similar phenotypes have previously been reported, suggesting that mimr1 is a novel male-sterile locus. Characterization of MIMR1 will provide further insights into the molecular basis for the development of plant reproductive organs.     

Alteration of floral organ identity in rice through ectopic expression of<Emphasis Type="Italic"> OsMADS16</Emphasis>

We used a transgenic approach and yeast two-hybrid experiments to study the role of the rice ( Oryza sativa L.) B-function MADS-box gene, OsMADS16. Transgenic rice plants were generated that ectopically expressed OsMADS16 under the control of the maize ( Zea mays L.) ubiquitin1 promoter. Microscopic observations revealed that the innermost-whorl carpels had been replaced by stamen-like organs, which resembled the flowers of the previously described Arabidopsis thaliana (L.) Heynh. mutation superman as well as those ectopically expressing the AP3 gene. These results indicate that expression of OsMADS16 in the innermost whorl induces stamen development. Occasionally, carpels had completely disappeared. In addition, ectopic expression of OsMADS16 enhanced expression of OsMADS4, another B-function gene, causing superman phenotypes. In the yeast two-hybrid system, OsMADS16 did not form a homodimer but, rather, the protein interacted with OsMADS4. OsMADS16 also interacted with OsMADS6 and OSMADS8, both of which are homologous to SEPALLATA proteins required for the proper function of class-B and class-C genes in Arabidopsis. Based on the gene expression pattern and our yeast two-hybrid data, we discuss a quartet model of MADS-domain protein interactions in the lodicule and stamen whorls of rice florets.     

Restoring full pollen fertility in transgenic male-sterile tobacco (Nicotiana tabacum L.) by Cre-mediated site-specific recombination

Producing hybrid seed requires an efficient pollination control system to prevent unwanted self-pollination. For further breeding, it would be advantageous to restore pollen fertility in the hybrids. In this work we demonstrate the use of tapetum-specific expression of a stilbene synthase (sts) transgene to induce pollen sterility in tobacco as has been shown previously. The sts-coding region was flanked by loxP recognition sites for Cre-recombinase. From 10 T₀-plants obtained, five proved to be male-sterile. They had smaller flowers with shorter stamina, but the vegetative phenotype was just as in the wild-type. Crossing male-sterile sts-plants with tobacco lines expressing the cre recombinase transgene resulted in site-specific recombination in the hybrids. GUS activity caused by fusion of the tap1-promoter with a promoterless gusA coding region indicated recombination events already in early stages of flower bud development. In all plants which had contained single or double sts-copies before crossing, these were excised, and pollen fertility was fully restored. The phenotype of these restored plants was as in wild-type controls. Contrary, from male sterile plants containing multiple copies of the sts-gene, not all copies were removed, and pollen sterility was maintained.