中间偃麦草2Ai-2染色体DNA文库构建及特异性序列的克隆

 以二体异附加系Z2与其普通小麦亲本宛7107杂交F1的花粉母细胞为材料,用原位杂交方法确定其中的单价体为中间偃麦草2Ai-2染色体;在此基础上,以显微分离、回收、LA-PCR (Linker-adaptor PCR) 扩增了该条染色体,扩增产物长度在0.15～3 kb之间,主要分布在0.2～2 kb。以α-32P-dCTP标记的中间偃麦草的基因组DNA为探针,对LA-PCR扩增产物进行杂交,证实扩增产物来自中间偃麦草。将扩增片段纯化后连接到质粒载体pUC18上,构建了2Ai-2染色体DNA文库。该文库包含约     

天蓝冰草和八倍体小冰麦对大麦黄矮病毒抗性的研究

 本文对天蓝冰草的两个变种——蓝色变种、茸毛变种，6种八倍体小冰麦——中1、中2、中3、中4、中5（中4无芒）和苏联多年生小麦及其亲本进行了抗大麦黄矮病毒（BYDV）的研究。试验中使用了GAV、GPV和PAV等3个BYDV株系。试验分别在温室和田间进行。结果表明，天蓝冰草的两个变种对BYDV免疫；6种八倍体小冰麦对BYDV都有抗性，其中中3、中4、中5和苏联多年生小麦高抗BYDV，中1和中2的抗性低于上述4种。在相同条件下，八倍体小冰麦的亲本小麦对BYDV均无抗性，说明八倍体小冰麦的抗性均来自天蓝冰草。 由于已知八倍体小冰麦中1和中2带有基本相同的天蓝冰草染色体组，而中3、中4和中5带有相同的天蓝冰草染色体组，苏联多年生小麦携带的天蓝冰草染色体组既不同于中2的，也不同于中3的，可能是另一个天蓝冰草染色体组。所以可以推测天蓝冰草对BYDV的抗性是由分布在3个染色体组中的多基因控制的。但3个染色体组所决定的抗性水平不同，其中的两个染色体组，即中3、中4、中5所携带的天蓝冰草染色体组和苏联多年生所携带的天蓝冰草染色体组抗性水平较高。另一个染色体组，即中1和中2所携带的天蓝冰草染色体组抗性水平较低。     

普通小麦-长穗偃麦草异附加系的分子标记鉴定

利用分布于小麦7个部分同源群的1 246对引物对15个可能的小麦-长穗偃麦草二体异附加系的4个亲本的基因组DNA进行扩增。结果表明,186对SSR、209对EST-SSR和22对STS引物能够在长穗偃麦草中扩增出不同于其他3个小麦亲本的特异条带,其中18对引物可以在14个附加系中的1~7个附加系扩增出长穗偃麦草的特异带,说明它们可能添加长穗偃麦草的遗传物质。5个附加系(1-3、1-8、1-27、2-6和2-22)可能含有长穗偃麦草第7同源群染色体,4个附加系(5-10、5-20、6-23和6-18)可能含有长穗偃麦草第6同源群染色体。附加系1-13可能附加2条不同同源群的长穗偃麦草染色体。同时发现,小麦与长穗偃麦草杂交及其后代衍生过程中长穗偃麦草染色体间可能发生遗传重组。     

组织特异表达启动子RSS1P在转TiERF1基因小麦中的应用

从水稻叶片中克隆了一个韧皮部组织特异表达的水稻蔗糖合酶启动子(RSS1P),将RSS1P与中间偃麦草乙烯反应因子基因TiERF1相融合构成组织特异表达的TiERF1基因表达盒,取代pAHC20中Ubi::bar基因表达盒,构建成无选择标记的韧皮部组织特异表达的pA20-RSS1P::TiERF1载体。利用基因枪将pA20-RSS1P::TiERF1与pAHC20载体混合、共轰击小麦品种扬麦12的幼胚愈伤组织,获得转RSS1P::TiERF1基因小麦。对该转基因小麦T₀和T₁代植株进行PCR、PCR-Southern、半定量RT-PCR和荧光定量PCR分析,证实外源RSS1P::TiERF1基因已转入受体,并且具有可遗传性;转入的RSS1P::TiERF1基因仅在根、茎、叶中表达,以根部表达量最高,在种子内不表达。纹枯病抗性鉴定和主要农艺性状考察结果表明,与受体扬麦12相比,转RSS1P::TiERF1基因小麦对纹枯病的抗性有明显提高,与转Ubi::TiERF1基因小麦的抗病性相当,而且转RSS1P::TiERF1基因小麦的农艺性状没有明显改变,说明可以利用RSS1P启动子创造更实用的转基因小麦新种质。     

Influence of sward condition on leaf tissue turnover in tall fescue and tall wheatgrass swards under continuous grazing

Two experiments were carried out on a tall fescue sward in two periods of spring 1994 and on a tall wheatgrass sward in autumn 2001 and spring 2003 to analyse the effect of sward surface height on herbage mass, leaf area index and leaf tissue flows under continuous grazing. The experiment on tall fescue was conducted without the application of fertilizer and the experiment with tall wheatgrass received 20 kg P ha^?1 and a total of 100 kg N ha^?1 in two equal dressings applied in March (autumn) and end of July (mid‐winter). Growth and senescence rates per unit area increased with increasing sward surface height of swards of both species. Maximum estimated lamina growth rates were 28 and 23 kg DM ha^?1 d^?1 for the tall fescue in early and late spring, respectively, and 25 and 36 kg DM ha^?1 d^?1 for tall wheatgrass in autumn and spring respectively. In the tall fescue sward, predicted average proportions of the current growth that were lost to senescence in early and late spring were around 0·40 for the sward surface heights of 30–80 mm, and increased to around 0·60 for sward surface heights over 130 mm. In the tall wheatgrass sward the corresponding values during spring increased from around 0·40 to 0·70 for sward surface heights between 80 and 130 mm. During autumn, senescence losses exceeded growth at sward surface heights above 90 mm. These results show the low efficiency of extensively managed grazing systems when compared with the high‐input systems based on perennial ryegrass.     

New insights into high-molecular-weight glutenin subunits and sub-genomes of the perennial crop Thinopyrum intermedium (Triticeae)

Intermediate wheatgrass (Thinopyrum intermedium) is a perennial crop that possesses desirable agronomic traits and provides environmental services, e.g., reducing soil erosion, nitrate leaching and inputs of energy and pesticide. Thus, intermediate wheatgrass is currently being domesticated as a perennial grain crop. However, the genetic information for molecular breeding is quite limited. Here we report a molecular analysis of high-molecular-weight glutenin subunits (HMW-GS) in intermediate wheatgrass using gene cloning and protein biochemistry. Five HMW-GS genes were isolated from individual intermediate wheatgrass plants: two x-type genes TiHGS1 and TiHGS4, and three y-type genes TiHGS2, TiHGS3 and TiHGS5. Among them, TiHGS5 was novel and possessed an additional cysteine residue at the N-terminal domain or repetitive domain. Sequence alignments showed that TiHGS1 and TiHGS2 genes shared high identities (>96%) with the Glu-1Dx and Glu-1Dy genes, respectively, in common wheat and Aegilops species, TiHGS3 with HMW-GS genes from Dasypyrum or Pseudoroegneria, and TiHGS4 and TiHGS5 with HMW-GS genes from Thinopyrum elongatum. This work provides substantial new insights into the gene compositions and protein profiles of HMW-GS in intermediate wheatgrass, and also gives evidence about the genome components of intermediate wheatgrass.     

对基因组原位杂交信号释译可能出现的片面性——来自一个小麦易位系(A-3)中外源遗传物质鉴定的启示

利用基因组原位杂交(GISH)和种子醇溶蛋白电泳(A-PAGE)技术对一个可能携带有10倍体长穗偃麦草(Thinopyrum ponticum (Host) Liu & Wang)遗传物质的小麦新种质A-3进行了综合鉴定. 用普通小麦"中国春"(Triticum aesticum L. cv. Chinese Spring)基因组(ABD)DNA作探针, 拟鹅观草[Pseudoroegneria stipifolia(Czern e     

Hybridization of Thinopyrum distichum and Secale cereale

An attempt was made to determine whether the salt tolerance genes of Thinopyrum distichum would be expressed in the presence of the rye genomes and if it would be possible to improve and utilize its hybrid with rye as a salt-tolerant fodder crop. Th. distichum florets were pollinated with diploid and tetraploid rye but hybrids were obtained only with tetraploid rye. The F₁ had 28 chromosomes and expressed high levels of salt tolerance. Fertility could not be induced through colchicines treatment but the plants produced some apomictic seeds during the summer months. The F₂ had 20-22 chromosomes and retained two complete or near-complete rye genomes. The F₂ plants responded better to colchicine treatment, however, the doubled hybrids remained male sterile. In summer, one F2 plant produced many apomictic seeds with chromosome numbers ranging from 14 to 16 (primarily rye chromosomes). The mechanism that caused the preferential loss of Thinopyrum chromosomes in each apomictic cycle remains unknown. The F₃ phenotypically resembled rye, had primarily reductional male meioses and produced seemingly functional pollen, but were self-sterile.     

抗黄矮病小麦新品系YW243的鉴定

对小麦新品系ＹＷ２４３黄矮病毒田间接种鉴定、细胞遗传学分析和分子原位杂交（ＧＩＳＨ）的结果表明：ＹＷ２４３高抗黄矮病毒ＧＰＶ、ＧＡＶ株系,体细胞染色体数目为２ｎ＝４２,花粉母细胞减数分裂中期Ⅰ染色体构型为２１Ⅱ,为小麦－中间偃麦草Ｔ７ＤＳ·７ＤＬ－７ＸＬ易位系,含有一对来自中间偃麦草的抗黄矮病基因;ＹＷ２４３抗性和农艺性状遗传稳定,可作为抗黄矮病育种的亲本材料．     

中间偃麦草SGT1基因的克隆及其抗病功能的分析

为了探索中间偃麦草SGT1基因在小麦抗病反应中的应用潜力,采用RT-PCR和RACE方法克隆出中间偃麦草SGT1基因,命名为TiSGT1。该基因编码蛋白具有SGT1蛋白典型的功能域结构,与大麦SGT1序列高度同源。通过基因重组技术构建了TiSGT1的高效组成型表达载体,通过基因枪法将该载体转化到小麦品种扬麦12基因组中。对转基因植株PCR、Southern杂交与RT-PCR分析表明,TiSGT1基因可在T0、T1和T2代转基因小麦中遗传和表达。黄矮病、白粉病抗性鉴定结果表明,SGT1的超量表达可以提高小麦对黄矮病、白粉病的抗性,TiSGT1可以作为小麦广谱抗病性改良的潜在基因资源。