棉纤维品质改良的分子生物学基础

本文简要地评述了棉纤维特异性表达基因和棉花纤维素合成酶基因的克隆及其表达方面的研究进展。与棉纤维伸长有关的基因主要有GhCAP和pGhEXl,与棉纤维次生壁加厚有关的基因主要有H6、Fb-E6和FSl8A等,但这些基因的精确功能还有待进一步研究。棉花celA是从第一个高等植物中克隆出的编码纤维素合成酶催化亚基的基因。利用转基因技术将抗虫、抗除草剂基因和这些与纤维发育有关的基因导入棉花,不但可改良棉花的产量和纤维品质,降低生产成本,而且可减轻对环境的不利影响,从而增强棉花的市场竞争力。     

水稻细胞质雄性不育分子生物学研究进展

对水稻细胞质雄性不育与叶绿体基因组、线粒体基因组、质粒基因组和核基因组的遗传以及育性相关基因的分子标记定位、辅助选择、克隆与表达研究现状进行了综述，并对水稻细胞质雄性不育分子机理和分子生物学研究进行了展望。     

Molecular markers for genic male sterility in Chinese cabbage

The gms gene of Chinese cabbage (Brassica campestris ssp. chinensis) conferring a recessivegenic male sterility was mapped with AFLPmarkers. Four markers were found to betightly linked to the gene with a distanceof <1 cM using a mapping population of327 individuals. The AFLPs were cloned andsequenced. Sequence derived primers yieldedclearly distinguishable PCR fragmentsrepresenting sequences tightly linked tothe gms gene. The sequence taggedsite (STS) markers can be used for markerassisted selection of male sterile plantsamong segregating populations.     

Characterization of transgenic male sterility in alfalfa

Dependable male sterility would help to make hybrid cultivar development a reality in alfalfa once higher levels of heterosis are attained. Alfalfa plants obtained by genetic transformation with a construct containing the Barnase gene under the control of a tobacco anther tapetum specific promoter were studied. Vacuolization and degeneration of the tapetal cell cytoplasm at a premeiotic stage of development were observed in all five transformed plants (T₀)examined, but the severity of the abnormalities varied greatly among pollen sacs of a genotype. During the meiotic stage, some pollen sacs showed reduction in size, and the tapetum generally appeared thinner when compared to those of the non transgenic plants; tapetal cells showed abnormal vacuolization and signs of cytoplasm degeneration. Despite this, some microspores were formed and some pollen grains were shed in all the T₀ plants, but these were highly variable in size and had very low in vitro germinability. Self-fertility was negligible. The T₀ plants were crossed with one or two unrelated non transgenic male-fertile plants. Mendelian segregation was observed with two exceptions. Instability of the trait in F₁ progenies was noticed, varying for different T₀ parents. F₁ plants exhibiting higher sterility than the primary transformants were observed, indicating that it should be possible to obtain good male sterile plants by backcrossing this trait into different genetic backgrounds. The possible use of this transgenic male sterility in alfalfa breeding is briefly discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Molecular advancements in male sterility systems of Capsicum: A review

In recent years, plant molecular research on genetic mapping, gene tagging and cloning, and marker-assisted selection (MAS) have gained importance in crop improvement programmes. In Capsicum, several inter- and intra-specific genetic maps with wide distribution of markers covering the whole genome have been developed. Recently, whole genome of the hot pepper C. annuum, its wild progenitor C. annuum var. glabriusculum and C. baccatum has been sequenced. The Capsicum genome size has been estimated to be approx. 4× (3.48 Gb) the genome size of cultivated tomato (Solanum lycopersicum L.) (900 Mb). Breeders’ access to the pepper genomic information would facilitate the choice of markers from different linkage groups, thus paving the way for gene cloning and its introgression into the elite breeding lines through MAS. Till date, approx. 20 independently inherited nuclear male sterility (NMS) genes have been reported. Linked markers have been identified for ms1, ms3, ms8, ms10, ms_k, msc-1 and an undesignated gene. However, markers tightly linked to ms8 and ms10 are still lacking. Except ms1, ms3, ms8 and ms10, the map position of other NMS genes is not known. In cytoplasmic male sterility (CMS), markers for the mitochondrial gene atp6 have been developed and the gene cloned. Number of markers some very tightly linked to the restorer-of-fertility (Rf) gene have been identified. However, the actual map position of the Rf locus is still not determined. Another CMS-associated nuclear gene “pr” responsible for restoring partial fertility has been identified and tagged. In this review, we have compiled up-to-date information about the marker technology relating to the NMS and the CMS-associated genes in Capsicum. This information can be useful when screening Capsicum germplasm, developing NMS lines through MAS, improving efficiency of the NMS system, transferring rf gene for maintainer line breeding and Rf genes for restorer line breeding in CMS and assessing genetic purity of the hybrid seed.     

Characterization of FAE1 in the zero erucic acid germplasm of Brassica rapa L.

The modification of erucic acid content in seeds is one of the major goals for quality breeding in oil-yielding Brassica species. However, few low erucic acid (LEA) resources are available, and novel LEA genetic resources are being sought. Fatty acid elongase 1 (FAE1) is the key gene that controls erucic acid synthesis. However, the mechanism for erucic acid synthesis in B. rapa lacks systematic study. Here, we isolated zero erucic acid lines from 1981 Chinese landraces of B. rapa and found that the formation of LEA is not attributable to variations in FAE1 coding sequences, as reported for B. napus, but may be attributable to the decrease in FAE1 expression. Moreover, the FAE1 promoter sequences of LEA and high erucic acid materials shared 95% similarity. Twenty-eight bases deletions (containing a 24-base AT-rich region) were identified approximately 1300 bp upstream from the FAE1 start codon in the LEA accessions. The genotype with the deletions co-segregated with the LEA trait in the segregating population. This study isolated an LEA B. rapa resource that can be exploited in Brassica cultivation. The promoter variations might modify the expression level of FAE1, and the results shed light on novel regulation mechanisms for erucic acid synthesis.     

水稻‘陆18S’核不育基因连锁的分子标记

为了研究水稻不育基因的遗传机理和连锁情况,利用‘陆18S’与3个父本杂交,并对F2进行花粉育性和结实率观察和遗传分析,同时对F2后代进行RAPD分子标记。通过遗传分析得知,‘陆18S’不育系由1对隐性核基因控制。通过分子标记的筛选,找到了与‘陆18S’雄性不育紧密连锁的RAPD标记S490,片段大小为850 bp。获得与不育基因紧密连锁的RAPD标记。为不育基因克隆、定位奠定了坚实的基础。     

Genetics and biology of cytoplasmic male sterility and its applications in forage and turf grass breeding

Hybrid breeding can exploit heterosis and thus offers opportunities to maximize yield, quality and resistance traits in crop species. Cytoplasmic male sterility (CMS) is a widely applied tool for efficient hybrid seed production. Encoded in the mitochondrial genome, CMS is maternally inherited, and thus, it can be challenging to apply in breeding schemes of allogamous self‐incompatible plant species, such as perennial ryegrass. Starting with a general introduction to the origin and the function of mitochondria in plants, this review focuses on the genetics and biology of CMS systems in plants to identify conserved and system‐specific mechanisms. We examine prospects of comparative mitochondrial genomics to identify candidate genes and causative polymorphisms associated with CMS across species and discuss specificities, obstacles and potentials of CMS as a breeding tool for maximizing heterosis in forage grasses. The purpose of the review is to highlight the importance of CMS and hybrid breeding in grasses, with the aim of facilitating research and development of novel breeding strategies to address the future needs for food, feed and biomass production.     

反义RNA技术在现代作物遗传改良中的应用

本文介绍了反义RNA的作用原理及其在作物遗传改良中的应用,主要有：1.在提高作者耐储藏性中的应用;2.在植物抗病虫中的应用;3.在提高作物品质中的应用;4.改变花卉颜色中的应用;5.雄性不育控制中的应用。     

Molecular mapping of a fertility restorer gene for cytoplasmic male sterility in soybean

In this study, we report the mapping of the Rf locus in soybean by microsatellite simple sequence repeat (SSR) genetic markers. A cross was made between cytoplasmic male sterility (CMS) line JLCMS82A and restorer line JIHUI 1 based on the DNA polymorphisms revealed by 109 SSR markers. A F₂ population derived from a single F₁ plant containing 103 individuals was used for mapping the Rf locus. The Rf gene of JIHUI 1 gametophytically restores male fertility to JLCMS82A. Fertile and semi-fertile DNA bulks and parental DNAs were screened with 219 SSR markers, and Satt215 which was previously mapped to soybean LG J, was found linked to the Rf gene. Five additional polymorphic SSR markers from LG J were used for analysis and a regional linkage map around the Rf locus was established. SSR markers, Sctt011 and Satt547, flanked the Rf locus at 3.6 cM and 5.4 cM, respectively. The availability of these SSR markers will facilitate the selection of restorer lines in hybrid soybean breeding.     

Specific developmental stages of gametogenesis for radiosensitivity and mutagenesis in rice

Summary Developmental stages during gametogenesis of rice were histologically examined in the period from differentiation of reproductive organs to anthesis. Plants were exposed to acute X-rays of 20 Gy. Radiosensitivity and mutation frequency were investigated in relation to the developmental stages of reproductive organs. The most radiosensitive stage, as measured by reduction of the M1 pollen-and seed-fertilities, was the last premeiotic interphase. Mutations induced at different developmental stages were scored in M3 strains. Sterility mutants and short-culm mutants were most frequently observed. Grain shape, panicle morphology, heading-date and endosperm character mutants were induced at a relatively low frequency. The overall mutation frequency varied with the developmental stage at the time of irradiation. The highest overall mutation frequency was observed when radiation was applied 10 days before anthesis, the late tetrad stage of microspores. Radiation exposure of florets at the late tetrad stage was found to be a more efficient method of inducing a large number of mutations than radiations applied to seeds and fertilized egg cells.     

Molecular mapping of the fertility-restoration gene Rf4 for WA-cytoplasmic male sterility in rice

The wild abortive cytoplasmic male sterility (CMS‐WA) system, an ideal type of sporophytic CMS in indica rice, is used for the large‐scale commercial production of hybrid rice. Searching for restorer genes is a good approach when phenotyping is very time‐consuming and requires the determination of spikelet sterility in testcross progeny. To establish more precisely the genetical and physical maps of the Rf4 gene, high‐resolution mapping of this locus was carried out using simple sequence repeat (SSR) markers and newly designed markers in a F₂ population. The genetic linkage analysis indicated that five SSR markers (RM6737, RM304, RM171, RM5841 and RM228) on the long arm of chromosome 10 were linked with the Rf4 gene. Rf4 was flanked by two SSR markers RM171 and RM6737 at distances of 3.2 and 1.6 cM, respectively. Also, within the region between Rf4 gene and RM171, a newly designed primer pair, AB443, produced two sterile‐specific markers, AB443‐400 and AB443‐500, 0.5 and 1.03 cM from the gene. The flanking markers identified give promise for their application in molecular marker‐assisted selection (MAS) and they are also suitable for starting chromosome walking to clone Rf4 gene in the near future.     

草莓乙烯受体FaEtr2基因的克隆及其反义表达载体的构建

为了构建草莓乙烯受体FaEtr2基因的反义表达载体,在已报道的FaEtr2基因序列的基础上,设计特异引物,克隆草莓乙烯受体FaEtr2基因部分特异序列,将该片段反向插入植物表达载体pBI121的CaMV 35S启动子和NOS终止子之间,构建了反义表达载体pBI121Etr2。通过双酶切鉴定后,导入农杆菌EHA105中,酶切和PCR鉴定表明质粒已导入到农杆菌中。本研究为后期该反义基因转化草莓品种以改良草莓果实耐贮运性打下基础。     

食用稻米品质性状间的相关性分析

对来自全国各地的8 390份稻米样品按籼型常规稻、籼型杂交稻、粳型常规稻和粳型杂交稻进行分类,并对其品质性状做了相关分析和多重比较。简单相关分析的结果表明：（1）在碾磨品质上,糙米率、精米率、整精米率两两极显著正相关;（2）在外观品质上,籼粳稻的长宽比与糙米率、精米率、整精米率、垩白率、垩白度均呈显著负相     

Molecular analysis of the fourth progeny of plants derived from a cytoplasmic male sterile chicory cybrid

Cytoplasmic male sterile (CMS) chicory cybrids have previously been obtained by fusion between chicory and CMS sunflower protoplasts. Preliminary restriction fragment length polymorphism analysis has shown mitochondrial recombination events in CMS plants and their progeny. The aim of this study was to investigate the fate of the mitochondrial genome of the fourth progeny derived from one CMS cybrid. Southern hybridization using several specific mitochondrial sequences as probes have revealed polymorphic patterns between the plants analysed and, consequently, the genetic instability of this genome. Presence of the sequence responsible for cytoplasmic male sterility in sunflower (orf522) was detected by polymerase chain reaction and confirmed by molecular hybridization in the CMS chicory plants; however, its part in CMS expression in chicory did not appear obvious. Moreover, different flowering phenotypes, including completely fertile plants occurred and no correlation could be established between the different mitochondrial profiles and the flowering types. These results suggested some hypotheses and questions about the molecular determinant of CMS in chicory, its regulation and expression and questions about the mitochondrial-nuclear interactions.     

Molecular mapping of a dominant genic male sterility gene Ms in rapeseed (Brassica napus)

Rs1046AB is a genic male sterile two‐type line in rapeseed that has great potential for hybrid seed production. The sterility of this line is conditioned by the interaction of two genes, i.e. the dominant genic male sterility gene (Ms) and the suppressor gene (Rf). The present study was undertaken to identify DNA markers for the Ms locus in a BC₁ population developed from a cross between a male‐sterile plant in Rs1046AB and the fertile canola‐type cultivar ‘Samourai’. Bulked segregant analysis was performed using the amplified fragment length polymorphism (AFLP) methodology. From the survey of 480 AFLP primer combinations, five AFLP markers (P10M13₃₅₀, P13M8₄₀₀, P6M6₄₁₀, E7M1₂₃₀ and E3M15₁₀₀) tightly linked to the target gene were identified. Two of them, E3M15₁₀₀ and P6M6₄₁₀, located the closest, at either side of Ms at a distance of 3.7 and 5.9 cM, respectively. The Ms locus was subsequently mapped on linkage group LG10 in the map developed in this laboratory, adding two additional markers weakly linked to it. This suite of markers will be valuable in designing a marker‐assisted genic male sterility three‐line breeding programme.     

中英德法俄美食品标准现状对比分析

通过研究为中国食品领域未来的国家标准制修订工作提供决策依据,为食品领域标准制修订、发布活动和标准化发展趋势提供风向标,为建立协调一致的食品安全标准体系提供知识服务支撑。基于文献计量学的方法从标准数量、标龄、发布年代、采标率、采标一致性程度、采标及时性等多个方面,将英、德、法、俄、美5 个国家食品领域的现行标准文献与中国现行标准文献进行对比分析。结果表明中国现行食品国家标准总数为2242 项;5 年以下标龄的标准百分比仅次于美国;标龄3~5 年的现行标准比例较高;标准发布高峰期在2009 年;中国食品标准的技术领域主要分布在农产食品综合、食品试验和分析的一般方法以及食品添加剂等,建议加强乳和乳制品、食品加工器具、包装材料和设备等标准研制;中国食品标准的国际标准采标率相对较低,仅为18.02%;采标一致性程度较其他几国低;采标时效性不高,采用近5年的国际标准数量较少,建议缩短采标时间差。     

不同遗传型香料烟若干性状的比较分析

对10份不同遗传型香料烟的农艺性状、产量、产值、品质性状、光合特性等性状进行比较分析,结果表明：沙姆逊×TOY和沙姆逊×Argjro两个杂种一代的综合性状表现明显地优于对照沙姆逊;香料烟杂种的优势既有正的又有负的,因不同组合而异;以沙姆逊作为母本的杂种一代在一些性状上优于相应的反交组合;不同遗传型香料烟在生长     

棉花种子特异性启动子的克隆及表达载体构建

种子特异性表达启动子是植物种子基因工程改良的重要工具.Lea(Late embryogenesis abundant)蛋白是胚胎发育后期种子中大量积累的一系列蛋白质,因此,其调控序列可能提供一个很好来源的种子特异性表达启动子.为研究植物Lea蛋白基因启动子在种子中的特异性表达,本研究通过PCR扩增,从亚洲棉(Gossy...