外源转入基因在小麦中的遗传规律及其对农艺性状的影响

Genetic Analysis of Alien Transferring Genes in Common Wheat and Their Effects on Agronomic Characters

利用农杆菌介导法将外源基因GUS和nptⅡ导入了3个小麦基因型新春9号、Bobwhite和PM97034,经对自交后代连续3代进行PCR、组织化学染色及ELISA检测和筛选,获得了纯合稳定转基因株系。以3个受体亲本为对照,随机区组、重复3次设计,对纯合稳定转基因株系进行了株高、穗长、穗粒数、穗粒重、千粒重、成熟期等农艺性状调查,研究外源转入基因对主要农艺性状的影响。结果表明,转基因株系除株高和生育期与对照有显著差异外,其他农艺性状差异均未达到显著水平。进一步以新春9号转基因株系与新春9号(CK)杂交,对F1代和F2代植株进行PCR、组织化学染色和ELISA检测,分析外源转入基因在小麦遗传背景中的遗传规律。结果表明,GUS基因和nptⅡ基因在F1代中表现完全显性,在F2代中呈现2.6∶1的分离比例,符合孟德尔遗传规律。

Some alien genes have been successfully introduced into wheat （Triticum aestivum L. ） mediated by either biolistic particle or Agrobacterium since the first report on the transformation of this specie in 1993. The segregation regulation of transfer genes or their effects on some main agronomic characteristics have been also investigated in the selfcrossing generation of transgenic plants by some researchers. However, the genetic role of introduced genes in the hybrid generations and the influence of same alien genes on the agronomic traits of different wheat cultivars have been studied seldom. It is very important to answer the above questions for the biosafty releasing of genetic modified wheat in the future. GUS reporter gene and nptH selection gene were transferred into three wheat genotypes of PM97034, Bobwhite, and Xinchun 9 by Agrobacterium-mediated transformation in our previous study, and homozygous transgenic lines were further obtained. A homozygous transgenic line derived from Xingchun 9 was used to be crossed with its wild type and genetic analysis of the two foreign genes were carried out in F1 and F2 generations by employing PCR, ELISA, and X-Gluc staining. All F1 plants were confirmed to be positive by the three tests, and it indicated that the Mien genes appeared dominant in F1 generation, and no gene lost or silence happened. 107 F2 plants were tested by PCR for nptH gene, in which 78 plants were demonstrated to be positive and other 27 plants to be negative. Seventy-five F2 plants were tested by X-Gluc staining for GUS gene, in which 54 plants were demonstrated to be positive and other 21 plants to be negative. These results suggested that the segregated ratio of the Mien genes in F2 generation was 2.6 ： 1, being consistent with Mendelian inheritance of 3 ： 1, and lost or silence of the foreign genes wasn＇t found in this generation, either. Fourteen T4 homozygous transgenic lines, among which 7 were derived from PM97034, 3 from Bobwhite, and 4 from Xinchun 9, were planted in field by random arrangement and 3 reduplications, in which three wild type varieties of PM97034, Bobwhite and Xinchun 9 were used as controls, and each material was planted for 5 rows by 3 meters in length. After PCR confirming at seedling stage, seven agronomic characteristics including growth duration, fertility, plant height, spike length, grains per spike, grain weight per spike, and 1000-grain weight were examined by taking 10 plants from each trial, and all collected data were analyzed by DPS computer software for variance difference. The results revealed that the inserting of the alien genes frequently changed plant height and growth period of wheat acceptors, and other main agronomic traits were not affected by the transferring genes obviously.