应用组织培养选育小麦抗黄矮病易位系的研究

组织培养再生的植株显示强烈的遗传变异能力,这一发现导致了实现外源基因渐渗的一个新途径。80年代初,W.R.Scowcroft 博士和 P.J.Lankin 博士提出体细胞无性系变异。大麦、燕麦、小黑麦和小麦等物种的体细胞无性系的细胞遗传分析进一步揭示了由于组织培养的结果出现更多的染色体重组(易位、倒置和缺失),这就为利用生物技术提高外源基因渐渗比例从而获得易位系、代换系、附加系提供了科学根据。小麦黄矮病是我国小麦的主要病害之一,至今在普通小麦中还未发现抗性材料。我们的研究旨在探索组织培养诱导易位系把外缘黄矮抗性导入小麦的可能性。     

用天花粉蛋白基因转化小麦获得转基因植株

取普通小麦品种京411未成熟胚诱导愈伤组织,10天左右,对820个胚性愈伤组织用含有35S启动子的天花粉蛋白（trichosanthin,TCS)基因轰击。2周后,将这些被轰击的愈伤组织转到含潮霉素50mg/L的筛选培养基上,经分化和生根,获得了33棵再生植株,经接饲毒蚜虫抗病性鉴定和PCR,Southern杂交分析,从中筛选出4株含有编码TCS的转基因小麦植株,转化频率为0．49％。     

小麦-大麦2H异代换系的鉴定

通过基因组原位杂交、重双端体测交及RFLP分析,解析了来自小麦品种 “中国春” (Triticum aestivumL. cv. “Chinese Spring” (CS))×大麦品种 “Betzes” (Hordeum vulgare L. cv. “Betzes”)杂种后代15份材料的遗传组成,鉴定出6个二体异代换系;对与 “中国春” 重双端体DDT2A、DDT2B及DDT2D测交的F1代花粉母细胞减数分裂中期染色体构型进行观察,同时以小麦第二部分同源群短臂探针psr131进行RFLP分析,鉴定出一套遗传稳定的小麦-大麦2H二体异代换系2H(A)、2H(B)和2H(D)。小麦第二部分同源群短臂探针psr131可作为追踪大麦2H染色体的RFLP标记。从代换系的生长势及其他农艺性状看,大麦2H染色体对小麦染色体2B和2D的补偿作用较好。通过考种观察到携带大麦a淀粉酶抑制蛋白基因的2H染色体导入小麦后,淀粉品质发生了改变,外观品质由原来“中国春” 的半粉质转变为代换系的半角质。     

Nucleolus organizer regions (Nor loci) of Chinese wheats

Nucleolus organizer regions (Nor loci) of a range of Chinese wheat landraces and cultivars (Triticum aestivum L. em Thell.) were analysed using genomic DNA extracted from leaves. Only two allelic variants of the Nor-B1 locus were found on chromosome 1B (Nor-B1a and Nor-B1g), while Nor-B1g was probably introduced from North America in the early 1960s. The even more recent introduction of the rye allele Nor-R1 in the early 1980s was also revealed. Eight allelic variants of the Nor-B2 locus on chromosome 6B (Nor-B2a, b, d, f, h, o, p and s) were identified. A Chinese origin for the a, d, f, o, p and s alkies is evident although the d allele was successfully introduced into Australian wheats in the early 1900s. Nor-B2h and Nor-B2b are again very recent introductions into Chinese wheat breeding programs, the former from CIMMYT wheats and the latter in association with the introduction of the 1RS/1BL translocation from Europe. On the basis of the presence of different combinations of Nor-B1 and Nor-B2 alleles     

携带抗黄矮病基因的中间偃麦草染色体2Ai_2特异的分子标记

The wheat-Thinopyrum intermedium addition lines Z1,Z2 contain a pair of Th. intermedium chromosomes 2Ai-2 carrying the gene with resistance to barley yellow dwarf virus (BYDV). Genomic in situ hybridization (GISH) was used to analyze the chromosome constitution of Z1,Z2 by using genomic DNA probes from Th. intermedium and Pseudoroegneria strigosa. The results showed that the chromosome constitution of either Z1 or Z2 composes of 42 wheat chromosomes and two Th. intermedium chromosomes (2Ai-2). The 2Ai-2 chromosome is St-E intercalary translocation, in which the E genomic chromosome segment translocated into the middle region of the long arm of chromosome belonging to St genome. With the genomic DNA probe of Ps. strigosa, the GISH pattern specific to the 2Ai-2 chromosome may be used as a molecular cytogenetic marker. A detailed RFLP analysis on Z1, Z2 and their parents was carried out by using 12 probes on the wheat group 2 chromosomes. Twenty RFLP markers specific to the 2Ai-2 chromosome were identified. Two RAPD markers of OPR16 –350 and OPH09 -1580, specific to the 2Ai-2 chromosome, were identified from 280 RAPD primers. These molecular markers could be used to assisted-select translocation lines with small segment of the 2Ai-2 chromosome and provide tools to localize the BYDV resistance.