Male sterility caused by cytoplasm of Brassica oxyrrhina in B. campestris and B. juncea

Summary Synthetic alloploid Brassica oxyrrhina (2n = 18, OO) x B. campestris (2n = 20, AA) was repeatedly backcrossed with B. campestris to place B. campestris nucleus in the cytoplasm of B. oxyrrhina. Alloplasmic plants, obtained in BC₅ generation, were stably male sterile but mildly chlorotic during initial development. Synthetic alloploid B. oxyrrhina-campestris was also hybridized with B. juncea to transfer B. oxyrrhina cytoplasm. Segregation for green and chlorotic plants was observed in BC₁ and BC₂ generations. By selection, however, normal green male sterile B. juncea was obtained in BC₃. Pollen abortion in both B. campestris and B. juncea is post-meiotic.     

苏联球茎大麦有利基因引入普通小麦的研究

本研究从1979年开始,用抗病性较强的苏联球茎大麦(4x)为父本,普通小麦品种中国春(6x)为母本进行属间杂交,经离体培养杂种幼胚,获得了属间杂种(F_1)。杂种自交不育,用秋水仙素加倍亦不成功,而以中国春5B单体与之回交,获得回交一代(BC_1F_1)。杂种F_1形态为两亲的中间型,其花粉母细胞染色体数在24—30条之间。BC_1F_1代杂种的形态与F_1相似,染色体数在45—49条之间(其中大多数细胞终变期有20—21个二价体和3—7个单价体)。BC_1F_1代自交或回交均有部分结实。以后各代继续自交分离;于1985—1986年,分离出6个异源二体附加系(2n=22Ⅱ)和异源八倍体(2n=28Ⅱ)以及若干个与母本形态有明显差异的整倍体杂种后代(2n=21Ⅱ)。这些整倍体和非整倍体后代中,有2个附加系的蛋白质含量较高(22.30％和20.37％);在整倍体后代中有两个株系与其父本一样对小麦黄花叶病(WYMV)具有抗性,而其母本与浙江省当前推广的小麦品种均不抗病,说明球茎大麦抗黄花叶病基因可能已导入母本中国春小麦。     

Physical mapping of translocation breakpoints in a set of wheat-Aegilops umbellulata recombinant lines using in situ hybridization

Aegilops umbellulata Zhuk. carries genes at Glu-U1 loci that code for a pair of high-molecular-weight glutenin subunits not found in common wheat, Triticum aestivum. Wheat-Ae. umbellulata recombinant lines were produced with the aim of transferring genes coding for glutenin subunits from Ae. umbellulata into wheat with minimal flanking material. We used fluorescent genomic in situ hybridization to evaluate the extent of recombination and to map physically the translocation breakpoints on 11 wheat-Ae. umbellulata recombinant lines. In situ hybridization was able to identify alien material in wheat and showed breakpoints not only near the centromeres but also along chromosome arms. To characterize and identify chromosomes further, including deletions along the 1U chromosome, we used simultaneous multiple target in situ hybridization to localize a tandemly repeated DNA sequence (pSc119.2) and the 18S–25S and 5S rRNA genes. One line contained an Ae. umbellulata telocentric chromosome and another two had different terminal deletions, mostly with some wheat chromosome rearrangements. Although from six independent original crosses, the other eight lines included only two types of intercalary wheat-Ae. umbellulata recombination events. Five occurred at the 5S rRNA genes on the short arm of the Ae. umbellulata chromosome with a distal wheat-origin segment, and three breakpoints were proximal to the centromere in the long arm, so most of the long arm was of Ae. umbellulata origin. The results allow characterization of recombination events in the context of the karyotype. They also facilitate the design of crossing programmes to generate lines where smaller Ae. umbellulata chromosome segments are transferred to wheat with the potential to improve bread-making quality by incorporating novel glutenin subunits without undesirable linked genes.     

Development and molecular cytogenetic analysis of wheat-Haynaldia villosa 6VS/6AL translocation lines specifying resistance to powdery mildew

Several Triticum aestivum L.-Haynaldia villosa disomic 6VS/6AL translocation lines with powdery mildew resistance were developed from the hybridization between common wheat cultivar Yangmai 5 and alien substitution line 6V(6A). Mitotic and meiotic C-banding analysis, aneuploid analysis with double ditelosomic stocks, in situ hybridization, as well as the phenotypic assessment of powdery mildew resistance, were used to characterize these lines. The same translocated chromosome, with breakpoints near the centromere, appears to be present in all the lines, despite variation among the lines in their morphology and agronomic characteristics. The resistance gene, conferred by H. villosa and designated as Pm21, is a new and promising source of powdery mildew resistance in wheat breeding.This research was supported by grants from the National High-Tech R and D Program and the National Science and Technology Commission     

Identification and molecular analysis of transgenic potato chromosomes transferred to tomato through microprotoplast fusion

 Results are reported on the integration sites and copy number of alien marker genes neomycin phosphotransferase II (nptII) and β-glucuronidase (uidA), introduced into diploid potato Solanum tuberosum through transformation by Agrobacterium tumefaciens. Also, the transgenic potato chromosomes 3 and 5 harbouring the nptII and uidA genes, which were transferred to tomato (wild species Lycopersicon peruvianum) by microprotoplast fusion, as revealed by genomic in situ hybridization (GISH), were identified by RFLP analysis using chromosome-specific markers. The data revealed three integration sites in the donor potato genome, each containing the uidA gene, and two also harbouring the nptII gene. Analysis of monosomic-addition hybrid plants obtained after microprotoplast fusion showed that each of these three integration sites is located on a different potato chromosome. The microprotoplast hybrid plants contained only the chromosomes that carried the selectable gene nptII. The data on sexual transmission of the donor potato chromosome carrying the uidA and nptII genes were obtained by analysing the first backcross progeny (BC₁) derived from crossing a monosomic-addition hybrid plant to tomato (L. peruvianum). The glucuronidase (GUS) assay and PCR analysis using primers for the uidA gene indicated the presence of the potato chromosome in GUS-positive and its absence in GUS-negative BC₁ plants. RFLP analysis confirmed sexual transmission of the potato chromosome carrying the nptII and uidA genes to the BC₁ plants. A few BC₁ plants contained the nptII and uidA genes in the absence of the potato additional chromosome, indicating that the marker genes were integrated into the tomato genome. The potential applications of the transfer of alien chromosomes and genes by microprotoplast fusion technique are discussed. Recieved: 1 September 1996 / Accepted: 20 September 1996     

一个短指(趾)少指(趾)节畸形家系的调查

本文报道了一短指(趾)少指(趾)节畸形苗族家系的调查结果。该家系中患者双手、双足第一指(趾)近节指(趾)骨变短粗,第二、三、四、五指(趾)中节指(趾)骨缺如,属于遗传性短指(趾)畸形的BellA-1型。患者手纹与贵州正常苗族人有较大差异。该家系父系正常,母系4代共调查75人,发现患者22人(男13人,女9人)。系谱分析表明,该畸形属常染色体显性遗传。     

河南省鸡公山国家级自然保护区外来入侵植物1994-2014年间的变化

以河南省鸡公山国家级自然保护区外来入侵植物为研究对象,对该地区1994 -2014年间外来入侵植物的变化进行了研究。结果显示,1951 -2010年信阳市每5年的平均温度明显上升、降水量年际间的波动较大;1994 -2014年的20年间,该保护区外来入侵植物从49种增加到60种,增长了22.4%,增加的11种外来入侵植物分别为:菊科4种,豆科2种,苋科、十字花科、大戟科、酢浆草科和雨久花科各1种;该保护区外来入侵植物主要来源于美洲、欧洲、亚洲和非洲,1994 -2014年间来自美洲的入侵植物共33种(其中新增加的有6种),占2014年外来入侵物种的50.0%以上;从生活型来看,外来入侵植物主要为陆生植物,占总数的95%以上,其中,一年生植物>一、二年生植物>多年生草本植物;从入侵途径来看,有意引进>无意引入>自然扩散;新增的入侵植物以种子作为主要繁殖方式的有9种。因此,对该保护区生物多样性保护和引种过程中,要加强对来自美洲的以种子作为主要繁殖方式的陆生草本植物的入侵风险进行监控和管理。     

Identification of alien chromatin specifying resistance to wheat streak mosaic and greenbug in wheat germ plasm by C-banding and in situ hybridization

Summary The chromosome constitutions of eight wheat streak mosaic virus (WSMV)-resistant lines, three of which are also greenbug resistant, derived from wheat/ Agropyron intermedium/Aegilops speltoides crosses were analyzed by C-banding and in situ hybridization. All lines could be traced back to CI15092 in which chromosome 4A is substituted for by an Ag. intermedium chromosome designated 4Ai-2, and the derived lines carry either 4Ai-2 or a part of it. Two (CI17881, CI17886) were 4Ai-2 addition lines. CI17882 and CI17885 were 4Ai-2-(4D) substitution lines. CI17883 was a translocation substitution line with a pair of 6AL.4Ai-2S and a pair of 6AS.4Ai-2L chromosomes substituting for chromosome pairs 4D and 6A of wheat. CI17884 carried a 4DL.4Ai-2S translocation which substituted for chromosome 4D. CI17766 carried a 4AL.4Ai-2S translocation substituting for chromosome 4A. The results show that the 4Ai-2 chromosome is related to homoeologous group 4 and that the resistance gene(s) against WSMV is located on the short arm of 4Ai-2. In addition, CI17882, CI17884, and CI17885 contained Ae. speltoides chromosome 7S substituting for chromosome 7A of wheat. The greenbug resistance gene Gb5 was located on chromosome 7S.Contribution No. 90-515-J from the Kansas Agricultural Experiment Station, Kansas State University, Manhattan, Kan., USA     

小麦品种小偃6号染色体结构变异的细胞学研究

本文报道了小麦品种小偃6号的染色体结构变异。小偃6号及其亲缘品种与中国春小麦杂交,杂种F_1染色体配对资料表明:小偃6号及其父本小偃96与中国春在染色体结构上有很大差异。八倍体小偃麦小偃693与小偃6号和小偃96杂种F_1减数分裂中期出现19″+2′′′+5′的染色体构型,说明小偃6号和小偃96至少含有两个长穗偃麦草染色体片段。将小偃6号与中国春双端体系列杂交,杂种F_1中1AL、2AS、5AS、6AS和7BS端着丝点染色体配对频率极显著地低于(中国春×小偃6号)F_1的平均染色体臂配对频率(90.1％),从而将小偃6号中的异源片段局限于这5个染色体臂内;同时发现:1AL、2DS、4DS、6AL及3B(t″s+t′L)端体中的端着丝点染色体参与了杂种F_1中多价体的形成,或与此有关,故认为小偃6号与中国春至少有两个相互易位的差异,涉及到染色体1A、2D、3B、4D和6A。文章还对小偃6号异源易位的起源和鉴定等进行了讨论。