New Methods in Genomic Research of Plants

Association mapping (as opposed to population mapping) is becoming more important in establishing associations between a phenotype and a genotype.The major advantage of association mapping,which depends on novel statistical methods,lies in the ability to use a collection of germplasm directly rather than taking the time and expense of developing a mapping population.Another advantage of association mapping is that the linkage disequilibrium values give a stronger LOD value,hence weak QTLs are more evident.     

A Preliminary Study of Mapping Genes Underlying Complex Traits Based on Chromosome Segment Substitution Lines

Complex traits are the features whose properties are determined by multiple factors, which can be genetic or environmental. Most of economically important characteristics of plants and animals belong to this special category. Hence, identification of genes underlying complex traits is theoretical and applied important. However, the conventional mapping populations with complex genetic background pose major challenge to distinguish the single QTL responsible for phenotypic variation. Paterson et al. （1990） pioneered the research on fine mapping of QTL by substitution mapping method. Nadeau et al. （2000） discussed the construction, applications and advantages of chromosome segment substitution （CSS） lines for dissecting complex traits. Indeed, CSS lines with the controlled genetic noise from genome background are ideal material for studying individual QTL as a Mendelian factor. In flee, CSS lines have been created for QTL fine mapping and further functional research （Ebitani et al., 2005; Xi et al., 2006）.     

Comparison of QTL for Grain Number per Panicle in Three Populations Sharing 3 Parents and Fine Mapping of Gnlc

Complex traits, such as yield components, are inherited in a quantitative manner and typically controlled by quantitative trait loci （QTL）. Grain number per panicle （GN） is an important component of yield in rice and has been studied for QTL mapping in our lab （Yu et al., 1997; Xing et al., 2002）. Further discovery of QTL for GN and fine mapping will provide rich of gene resources for high yield breeding by marker assistant selection. Gene cloning is helpful to understand the biological mechanism underlying GN and instruct the application of gene engineering in rice yield breeding. In recent years, near-isogenic lines （NILs） for grain number have been reported for gene fine mapping （Tian et al., 2006; Zhang et al., 2006） and gene cloning （Ashikari et al., 2005）. However, so far, this kind of research is insufficiency for systematically elucidating the genetic bases and regulatory mechanism involved in GN. In this study, we compare the locations and genetic effects of QTL for GN detected in three sets of recombinant inbred line populations （RILs） sharing three parents, and fine map a new major QTL, Gnlc, commonly detected in the 3 populations.     

The Power of Integrative Approaches to Develop Markers for Maize Molecular Breeding

Recent advances in genomics and bioinformatics now offer real opportunities for dissecting complex Waits into their component sub-traits, which will simplify the process of developing the tools necessary to manipulate the underlying genes （Varshney et al., 2005）. The value of molecular markers as a complement to phenotyping under several breeding scenarios is largely unquestioned, as demonstrated by the increasing number of successful studies published （Varshney et al., 2006）. However most experiments have targeted crop improvement for disease resistance, morphological waits or quality waits （Franca et al., 2005） and there is still some way to go before markers can be used routinely and ubiquitously to breed for complex waits, such as tolerance to abiotic stress （Ribaut and Ragot, 2007）. The combination of genetic mapping and association studies has considerable potential to generate a catalogue of genetic variation, and thereby present novel opportunities for selection based on genome-wide scans （Biswas and Akey, 2006）. Nevertheless, it remains to be seen whether the outcome of gene interactions, particularly where significant gene networks are involved,     

Development of Permanent Mapping Populations RILs in Diploid A Genome

Recombinant inbred lines (RILs) serve as powerful tools for genetic mapping.RILs are obtained by crossing two inbred lines followed by repeated selfing or sib-mating to create a set of new inbred lines.The resulting genome in the finally developed RILs is a mosaic of the parental genomes.The fixed variation in RILs is used of for fine mapping of complex traits.Cultivated diploid A genome species of cotton holds special significance to dissect complexity of a developing cotton fibers.We have evaluated the interspecifc population (Gossypium arboreum var.     

Positive Fixed Points for Upper Semicontinuous Set-valued 1-set-contractive Mapping

Using topological degree for upper semicontinuous set-valued 1-set-contractive mapping and the fixed point theorems for upper semicontinuous set-valued 1-set-contractive mapping, the boundary conditions of existing positive fixed points is studied for upper semicontinuous set-valued 1-set-contractive mapping. In fact, it is a natural conclusion in the cone for the fixed point theorems of upper semicontinuous set-valued 1-set-contractive mapping, and it is a natural extend for positive fixed point theorems of single-valued 1-set-contractive mapping.     

Research on Mapping Method of Customer Need Information in Product Family Improvement

Aiming at ensuring that product family improvement is based on customer needs while taking full advantage of enterprise history database, firstly, customer needs in the product family improvement are expressed. Then a method of realizing the mapping of customer needs to functional requirements is presented, which is based on quality function development and association rule mining. Finally, an example illustrates the good application of the method.     

Analysis of Quality Problems and Their Traits of Main Structure in Construction Engineering

The main structure in construction engineering is the organic part of the load - carrying system of construction engineering. Its quality is the core for realizing the value of construction engineering quality. The essence of its quality problems is that the quality behavior, intermediate output or final product of the construction body cant meet the requirements of national laws, regulations and obligatory criteria during construction work. Its quality problems have the following eight traits such as complexity, frequent occurrence, potentiality, chain effect, heavy damages, multiple responsibilities, difficulties of treatment and high expenditure for treatment.     

Mapping QTLs for Yield Stability in Durum Wheat Grown under Different Water Regimes

Among the most important Mediterranean annual crops, durum wheat is widely grown in drought-prone areas. Therefore, improving water-use efficiency （WUE） of durum wheat represents a major breeding goal. IDu-WUE （Improving Durum wheat for Water Use Efficiency and yield stability through physiological and molecular approaches） is a collaborative project among public and private research centres in Italy, Spain and WANA （West Asia and North Africa） countries （Morocco, Tunisia, Syria and Lebanon） funded by the European Union aimed at investigating the genetic variation for WUE and yield stability in durum wheat grown in Mediterranean droughtprone areas. During the first year of the project, a number of morpho-physiological traits （e.g. early vigour, flowering time, leaf rolling, number of fertile tillers, etc.）, WUE, WUE-related traits （e.g. carbon isotope discrimination, canopy temperature, chlorophyll fluorescence, etc.）, yield and its components have been investigated in a RIL population （249 lines） and a collection of ca. 190 durum wheat accessions characterized by a high level of linkage disequilibrium （Maccaferri et al., 2005）,     

Metabolic Engineering of Carotenoid Formation in Carrot Roots

Carotenoids, a large class of yellow, orange and red pigments accumulate in the chloroplasts of leaves or in the chromoplasts of many flowers and fxuits as well as carrot roots. In plants, carotenoids function as accessory pigments in photosynthesis, eolourants in flowers, fxuits and roots, biosynthesis of abseisie acid （ABA）, an important regulator of plant growth. In photosynthetic tissue, the dominant function of carotenoids is the quenching of the triple chlorophyll as a mechanism to protect the photosynthetic apparatus. Carotenoids exert protective functions due to their high antioxidative potential and also important components of the human diets. Since humans and animals are unable to synthesize earotenoids de novo, they must rely upon dietary earotenoids. Different earotenoids have different beneficial effects in human body. All earotenoids （e.g. alpha-carotene, beta-carotene and beta-eryptoxanthin） that contain a beta-ring can be converted to retinol and are thus precursors for vitamin A in human and animal diets. Because of the epsilon ring, alpha-carotene has only half the provitarnin A activity compared to that of beta-carotene. Therefore, it is after lyeopene formation that carotenoid biosynthetic pathway diverges and produces either more or less provitarnin A activity carotenoid,     

水稻早衰叶突变体PLS2的遗传分析与基因定位

叶片早衰引起叶绿素和其他大分子被降解, 叶片光合能力降低。这个过程常伴随着活性氧(ROS)的积累, 以及细胞中抗氧化酶(SOD、CAT和APX)活性的降低, 衰老相关基因(SAG)表达量上调, 最终导致整个植株过早成熟, 产量降低。因此, 研究水稻早衰遗传机制和基因功能对于水稻的遗传改良具有重要的作用和意义。PLS2是通过航天育种工程经空间辐射诱变得来的突变体, 在孕穗期表现早衰。与野生型相比, PLS2的光合能力降低, 株高变矮, 节间和穗长缩短, 分蘖数和有效分蘖数减少, 穗粒数和结实率明显下降, 千粒重降低, 穗发育不良, 灌浆不充分; 叶片的CAT活性显著降低、H₂O₂积累、死亡细胞增加, 叶绿体结构变差, 叶绿体中淀粉和嗜锇颗粒增多。黑暗处理加速突变体叶片衰老, 叶绿体超微结构球状化。利用PLS2/蜀恢527和PLS2/02428的隐性定位群体, 将pls2定位在第3染色体标记RM14704 (8674283 bp)与SL-I-5 (8758394 bp)之间, 物理距离84.11 kb, 区间内包括14个基因, 测序发现在LOC_Os03g15840第9个外显子第41位的C被替换为T, 导致精氨酸(R)替换为半胱氨酸(C), LOC_Os3g15840编码水稻中的一个糖基转移酶(glycosyltransferases, GTs), 可能是pls2的候选基因。为下一步调控基因的克隆和功能研究奠定了基础。     

水稻穗大小决定基因PS1的遗传分析及克隆

穗大小是影响水稻产量的重要农艺性状之一。本研究在水稻粳稻品种"中花11号"T-DNA插入突变体库中鉴定了一个植株略矮、穗长变短25%、一次枝梗和二次枝梗数目分别减少33%和80%、且粒型变异的突变体。T-DNA标签共分离检测表明:该突变体的表型与T-DNA插入无关。通过与籼稻品种"珍汕97"配置杂交组合构建遗传作图群体,F2杂合后代符合经典孟德尔遗传分离比3:1,证明突变性状受一对隐性基因PS1(Panicle Size 1)所控制。采用图位克隆的方法,将基因PS1初步定位在第11号染色体短臂上的IN44和IN50标记之间,两标记物理图距为105 kb。对候选基因进行进一步的表达量分析、比较扩增及测序发现基因LOC_Os11g12740(即SP1)可能是本研究的PS1基因。本研究为进一步分离克隆PS1基因及对水稻穗大小发育的深入研究提供依据。     

棉花阿拉伯半乳糖蛋白基因的克隆、表达与染色体定位分析

陆地棉李氏超短纤维突变体(Li1li1)是显性单基因突变体,表现为茎秆、叶片卷曲,纤维短至6mm,其隐性纯合体(li1li1)则表现为株型和纤维发育都正常。对开花后10d的李氏纤维发育正常材料(li1li1)和超短纤维突变体(Li1li1)胚珠纤维混合体进行mRNA差异显示反转录PCR(DDRT-PCR)分析,获得1条在李氏纤维发育正常材料中上调表达的差异片段。进一步通过5'RACE技术获得全长为621bp的cDNA,测序及DNA序列的生物信息学分析表明该cDNA片段与拟南芥编码阿拉伯半乳糖蛋白基因AGP14有52%相似性,故命名为GhAGP。表达特征分析表明,该基因在陆地棉根、茎、叶和纤维中组成性表达,在棉纤维中优势表达。基因组序列分析显示,该基因在二倍体棉种非洲棉和雷蒙德氏棉中各有1个拷贝,在四倍体棉种陆地棉TM-1和海岛棉海7124中分别存在2个拷贝,表明A、D亚组中各有1个拷贝。利用本实验室陆地棉遗传标准系TM-1和海岛棉海7124培育的含140个单株的BC1作图群体,将GhAGP基因的2个拷贝分别定位在四倍体棉花部分同源转化群染色体6和染色体25上。     

一个新的棉花MYB类基因(GhTF1)的克隆及染色体定位分析

MYB类转录因子是指含有MYB结构域的一类转录因子,广泛参与植物发育和代谢调节。含2个MYB结构域的R2R3类MYB转录因子在植物体内主要参与次生代谢的调节和控制细胞的形态发生。从优质材料7235不同发育时期的棉纤维混合cDNA文库中克隆了一个棉花MYB转录因子基因GhTF1（GenBank登录号：EF651783）。该cDNA序列长1115bp,其开放读码框长度为771bp,编码256个氨基酸。表达特征分析表明,该基因在陆地棉7235不同组织中均表达,但表达量不同,特别在开花前1d,开花后8d和11d的纤维细胞中优势表达。该基因在二倍体棉种非洲棉和雷蒙德氏棉中开放读码框区的序列较保守,但在非编码区差异较大,在内含子区存在大片段插失和碱基替换现象。Southern杂交结果表明该基因在陆地棉基因组中存在2个拷贝,推测A、D亚组中各有1个拷贝。利用海7124和TM-1两亲本配置的BC1作图群体,将GhTF1定位在染色体10上。     

水稻减数分裂异常突变体osmd的表型分析及基因定位

减数分裂是有性生殖生物繁殖的基础,减数分裂和受精过程的正常进行保证了有性生殖生物配子体和合子体世代交替,并维持了遗传物质的稳定性。因此发现和克隆减数分裂相关基因可为进一步理解减数分裂调控过程提供研究基础。通过正向遗传学方法,筛选一个水稻减数分裂相关突变体并将其命名为osmd(Oryza sativa meiosis defect)。对其生长过程、花器官、花粉育性进行观察分析;通过DAPI,FISH染色对其进行染色体行为分析;并对该突变体进行遗传分析、基因定位和候选基因分析。结果表明,与野生型相比,osmd突变体营养生长过程正常,花器官以及雌蕊形态正常,但是成熟期花药不饱满,花粉粒不能被I2-KI染色。对突变体osmd花粉母细胞减数分裂过程观察发现,在粗线期染色体不能完全配对、终变期出现单价体、二分体时出现滞后染色体、四分体时期出现多个微核。通过FISH试验确定osmd突变体同源染色体不能正常配对。遗传学分析表明,osmd突变体不育表型由一个单核隐性基因控制;通过图位克隆将osmd的突变位点定位到10号染色体上的2个Indel分子标记Chr10-312和Chr10-1003-3之间,该区间共有900 kb,有133个开放阅读框。该区间内一个已知水稻减数分裂相关基因OsPAIR3编码区序列无变化。由此推测Os MD是一个未报道的参与水稻减数分裂同源染色体配对过程的蛋白。     

小麦细胞分裂素氧化/脱氢酶基因(TaCKX2)的克隆及其遗传作图

细胞分裂素几乎参与调控了植物生活周期中所有的生长发育过程,细胞分裂素氧化/脱氢酶(CKX)是降解细胞分裂素的关键酶。本研究采用同源克隆结合文库筛选的方法,分离得到普通小麦的TaCKX2基因(与水稻OsCKX11直向同源),针对基因序列开发出SSR标记TaCKX2_SSR,使用缺体-四体和RILs群体将TaCKX2定位于7B、7D染色体。分离得到的TaCKX2基因及其作图信息将为今后进行小麦CKX基因的功能研究以及小麦重要农艺性状的遗传改良奠定基础。     

Research Progress on the Mendelian Genetic Analysis and Molecular Mapping of Morphological Qualitative Traits in Cotton

Genetic analysis and molecular mapping of qualitative traits are important tools in cotton breeding. Research on cotton qualitative traits has been reported since the early 1900s. Rapid advances in cotton genomics and molecular mapping over the past several years have facilitated the mapping and cloning of important qualitative trait genes in cotton. Although most of the 101 genes and alleles related to cotton morphological qualitative traits have not been mapped to linkage groups or chromosomes, several genes have been cloned and identified via map-based cloning. This paper describes research progress on the genetic and linkage analysis, molecular mapping, and candidate gene cloning of eight major types of morphological qualitative traits: plant color, leaf color, leaf shape, bract, flower, nectary, gland, and fiber characteristics. The presented information lays a foundation for studying the molecular basis of qualitative traits, favorable gene-based transfer, and gene pyramiding in cotton.     

一个新的水稻窄叶突变体的遗传分析和基因定位

水稻叶片形态相关突变体是水稻功能基因组学研究和株型改良的重要材料.本研究以新的窄叶突变体MR11为研究材料,发现该突变体在整个生育期表现为窄叶、叶长变短和植株矮化.叶片组织结构观察发现由于叶脉数减少和叶脉问宽度减小,导致突变体倒二叶叶片宽度不及野牛型的1/2.F2和BC1F1两个群体分离结果表明该窄叶突变体表型受一对隐...     

拟南芥下胚轴向光弯曲P2SA2基因的克隆与功能鉴定

向光素PHOT1介导较宽范围蓝光诱导的下胚轴向光弯曲,而向光素PHOT2仅在强蓝光下起作用。强蓝光下,PHOT1和PHOT2介导拟南芥下胚轴向光弯曲的功能冗余性,限制了人们对PHOT2功能的研究。为此,以拟南芥phot1突变体为材料,避开PHOT1基因的干扰,通过EMS诱变筛选拟南芥下胚轴向光不弯曲突变体,成功克隆到1个基因,命名为P2SA2(phototropin 2 signaling associated 2),该基因被证明是NPH3的等位基因。P2SA2基因的突变可导致拟南芥缺失强蓝光诱导的下胚轴向光弯曲反应。在p2sa2突变体背景下,P2SA2基因超表达可恢复强蓝光诱导的拟南芥下胚轴向光弯曲。该结果将为强蓝光下PHOT2下游基因的筛选、功能鉴定和揭开PHOT2调节强蓝光诱导的下胚轴弯曲的机制提供理论基础。     

一个新的棉花MYB类基因(GhTF1)的克隆及染色体定位分析

MYB类转录因子是指含有MYB结构域的一类转录因子, 广泛参与植物发育和代谢调节。含2个MYB结构域的R2R3类MYB转录因子在植物体内主要参与次生代谢的调节和控制细胞的形态发生。从优质材料7235不同发育时期的棉纤维混合cDNA文库中克隆了一个棉花MYB转录因子基因GhTF1(GenBank登录号: EF651783)。该cDNA序列长1 115 bp, 其开放读码框长度为771 bp, 编码256个氨基酸。表达特征分析表明, 该基因在陆地棉7235不同组织中均表达, 但表达量不同, 特别在开花前1 d, 开花后8 d和11 d的纤维细胞中优势表达。该基因在二倍体棉种非洲棉和雷蒙德氏棉中开放读码框区的序列较保守, 但在非编码区差异较大, 在内含子区存在大片段插失和碱基替换现象。Southern杂交结果表明该基因在陆地棉基因组中存在2个拷贝, 推测A、D亚组中各有1个拷贝。利用海7124和TM-1两亲本配置的BC₁作图群体, 将GhTF1定位在染色体10上。