Spencer T M, O'Brien J V, Start W G, Adams T R, Gordon-Kamm W J, Lemaux P G
Discovery Research, DEKALB Plant Genetics, Groton, CT 06340.
Plant Mol Biol. 1992 Jan;18(2):201-10. doi: 10.1007/BF00034949.
Progeny recovered from backcrossed transgenic maize tissue culture regenerants (R0) were analyzed to determine the segregation, expression, and stability of the introduced genes. Transgenic A188 x B73 R0 plants (regenerated from embryogenic suspension culture cells transformed by microprojectile bombardment; see [9]) were pollinated with nontransformed B73 pollen. Inheritance of a selectable marker gene, bar, and a nonselectable marker gene, uidA, was analyzed in progeny (R1) representing four independent transformation events. Activity of the bar gene product, phosphinothricin acetyltransferase (PAT), was assessed in plants comprising the four R1 populations. The number of R1 plants containing PAT activity per total number of R1 plants recovered for each population was 2/7, 19/34, 3/14 and 73/73. Molecular analysis confirmed the segregation of bar in three R1 populations and the lack of segregation in one R1 population. Cosegregation analysis indicated genetic linkage of bar and uidA in all four R1 populations. Analysis of numerous R2 plants derived from crossing transformed R1 plants with nontransformed inbreds revealed 1:1 segregation of PAT activity in three of four lines, including the line that failed to segregate in the R1 generation. Integrated copies of bar in one line appeared to be unstable or poorly transmitted.
对回交转基因玉米组织培养再生植株（R0）的后代进行分析，以确定导入基因的分离、表达和稳定性。用未转化的B73花粉对转基因A188×B73 R0植株（由通过微粒轰击转化的胚性悬浮培养细胞再生而来；见[9]）进行授粉。在代表四个独立转化事件的后代（R1）中分析了选择标记基因bar和非选择标记基因uidA的遗传情况。在包含四个R1群体的植株中评估了bar基因产物膦丝菌素乙酰转移酶（PAT）的活性。每个群体回收的R1植株总数中具有PAT活性的R1植株数量分别为2/7、19/34、3/14和73/73。分子分析证实了bar在三个R1群体中的分离以及在一个R1群体中未分离。共分离分析表明bar和uidA在所有四个R1群体中存在遗传连锁。对由转化的R1植株与未转化的自交系杂交产生的大量R2植株进行分析，结果显示在四个株系中的三个株系中PAT活性呈1:1分离，包括在R1代未发生分离的株系。一个株系中bar的整合拷贝似乎不稳定或传递不佳。
