Evolving gene pools in crop plants

Summary The three gene pool system can be applied usefully to the whole range of crop plants. The primary gene pool (GP1) show varying degrees of fragmentation. No morphological discontinuity is apparent between wild and cultivated Lathyrus sativus but clear discontinuities have developed between conspecific wild and cultivated Phaseolus and Vigna species. Further discontinuities can develop in cultigens where disruptive selection has been practiced, as in Beta vulgaris, Linum usitatissimum and Brassica oleracea where more than one distinct crop has evolved within a single biological species. Each such crop has developed its own distinctive gene pool.     

Gene flow from transgenic wheat and barley under field conditions

In this study the frequency and distance of gene flow from transgenic wheat (Triticum aestivum) and barley (Hordeum vulgare) to non-transgenic wheat and barley crops was investigated under local field conditions. Trials were conducted in the Australian Capital Territory (ACT) and in South Australia (SA). Gene flow from transgenic wheat was confirmed at frequencies of 0.012% and 0.0037% in the ACT and SA, respectively. In both trials gene flow occurred over distances of less than 12 m. Gene flow was also detected from transgenic barley at a frequency of 0.005%, over a distance of less than 12 m. The results show that under Australian field conditions, gene flow occurs at extremely low frequencies and over very short distances. Physical separation of transgenic and non-transgenic cereal crops by greater than 12 m should ensure that contamination of adjacent non-transgenic cereal crops remains less than 0.02%, well below the level permitted under Australian regulations.     

辣椒诱导再生及黄瓜花叶病毒外壳蛋白基因转化研究初报

用MS+5mg6BA+0.1mgIBA诱导辣椒子叶外植体分化出叶状体.用MS+3mg6BA+0.2mgIBA诱导出茎芽.再用MS+0.2mgIAA诱导生根,从而得到完整的小植株.直接以子叶外植体为受体,以Ti质粒为载体将CMVcp(黄瓜花叶病毒外壳蛋白)基因转化进辣椒,经再生性培养获得了转基因小植株.     

粳稻叶绿体基因组的密码子用法

基因组密码子使用受多种因素的影响，本试验通过对应分析探讨了若干重要因子对粳稻品种“日本晴”叶绿体全基因组序列密码子用法的效应，结果指出，在影响最大的第一条向量轴上，基因的位置坐标与该基因的表达水平（CAI）和GC3s极显著相关（r = 0.785**和－0.804**），而CAI与GC3s高度负相关（r = －0.917**）；说明基因表达     

圆果黄麻茎中花青素的遗传研究

对６个中国圆果种黄麻茎中花青素的遗传研究表明，其Ｆ２代群体有呈３：１，９：３：４，９：７或１３：３的分离比率，此遗传现象可以用Ｃ－ｃ，Ａ＾Ｄ－Ａ＾Ｌ－ａ和Ｒ－ｒ的基因互作和复等位基因的作用解释。     

石榴POD基因家族鉴定及生物信息学分析

为解析石榴POD基因家族的特征,本研究利用生物信息学技术对石榴POD基因家族成员进行鉴定,并对其理化性质、二级结构、亚细胞定位、系统进化关系和保守基序等进行了预测分析。结果表明,石榴中共鉴定出107个POD基因家族成员,其大部分为碱性蛋白、稳定蛋白和亲水性蛋白。蛋白二级结构以α-螺旋和无规则卷曲结构为主要构成元件。亚细胞定位表明POD蛋白主要分布在细胞质中。根据系统进化关系可分为11个亚族,每个亚族基因的数量不同,第5个亚族最多。聚在同一亚族POD蛋白的保守基序组成相似,其进化关系较近。研究结果为深入分析石榴POD基因的功能,揭示其调控石榴果实褐变的机理提供了科学依据。     

郑麦9023春化基因VRN-1的组成及表达

以郑麦9023叶片为材料,利用序列特异性PCR扩增技术克隆了春化基因VRN-1,并通过0~2℃冰箱模拟春化处理0、10、20和30 d,对该基因在一叶期至九叶期叶片中的表达进行了分析。PCR分析表明,VRN-1基因在郑麦9023的A和D基因组中均为隐性,在B基因组中为显性,基因等位类型为vrnA1VrnB1vrnD1。在克隆VRN-A1、VRN-B1和VRN-D1基因序列的基础上,设计了3个等位基因的特异引物,并利用该特异引物进行半定量RT-PCR分析。结果显示,在未经春化处理的条件下,一叶期VRN-A1和VRN-D1均未检测到表达,而VRN-B1已有较低水平的表达;从三叶期开始,3个等位基因都有较高水平的表达,并一直持续至开花期。在春化处理10、20和30 d条件下,VRN-1的3个等位基因在一叶期就出现较高水平的表达,并保持至开花期。     

分子标记辅助选择聚合棉花Rf1育性恢复基因和抗虫Bt基因

胞质雄性不育恢复系0-613-2R与转Bt基因抗虫棉R019(轮回亲本)杂交、回交产生BC2群体。利用CMS恢复基因Rfl紧密连锁的3个SSR标记和Bt基因的PCR标记开展分子标记辅助选择培育聚合有Rfl和Bt的转基因抗虫棉恢复系。在分析的59个BC2单株中55株存在恢复基因标记，54株存在Bt基因；综合标记分析结果，共获得54个同时具Rfl与Bt基因的聚合单株；这些聚合单株自交后，通过标记辅助选择，获得10株含Bt基因且Rfl纯合的单株。为棉花优良恢复系的快速培育提供了重要基础。     

A genomic library of Lycopersicon pennellii in L. esculentum: A tool for fine mapping of genes

The cultivated tomato contains only a small fraction of the genetic variation present in its wild relatives. In order to use the wild germplasm in tomato breeding and genetic studies we developed a new kind of genetic resource which is composed of 50 L. esculentum lines each containing a single introgression from the green fruited species L. pennellii (LA 716). Each of the introgression lines is nearly isogenic to the cultivated tomato; these lines provide complete coverage of the wild species genome. The lines contain on the average an introgression of 33 cM from a total genome size of 1200 cM. The size and identity of the introgressed segments was determined based on RFLP analysis of 350 markers. This resource can be viewed as a genomic library of the wild species in the cultivated background. It covers the entire genome with single independent inserts per line and therefore every phenotypic difference between the introgression lines can be associated with the unique introgressed segment. The development and potential application of this resource are discussed.     

甘蓝型油菜防御素基因的克隆与表达分析

植物防御素具有广谱抗菌活性,不仅具有抗真菌、抗细菌、蛋白酶抑制和昆虫淀粉酶抑制等活性,而且参与调节植物的生长和发育。本研究根据白菜防御素基因序列设计引物,从甘蓝型油菜中克隆获得5个防御素基因,其c DNA全长325~461 bp,含有177~243 bp开放阅读框,编码58~80个氨基酸,含有8个保守Cys残基,具备Knot1功能域。系统进化分析表明,Bn PDF2.1、Bn PDF2.3、Bn PDF2.5与拟南芥PDF2亲缘关系较近,可能具有蛋白酶抑制活性。荧光定量分析表明,防御素基因具有组织表达特异性,在花蕾和叶中表达量较高,角果中次之;经1 mmol L–1水杨酸处理开花期油菜2 h后,防御素基因在茎、花蕾、角果中的表达量均有不同程度的上调,但在叶中表达有所下调,在根中表达无明显变化。