对6000多个转基因TDNA插入水稻株系进行异常遗传分离分析(选择标记基因为潮霉素磷酸转移酶基因hpt),发现216个转基因株系的TDNA呈现1∶1分离。接着利用测交方法检测TDNA的遗传规律,初步确定其中57 个候选株系为雄配子不育候选突变体。随后对候选突变株进行多代遗传分析及花粉细胞学观察,结果表明其中的38个突变体花粉黑染率约为50%,自交后代TDNA的异常分离是由于转基因植株的花粉半不育所致,TDNA的传递只能通过雌配子体。另外,利用ELISA定量测定突变体中cry1Ac(Bt)基因编码蛋白的表达量,发现花粉的这种不育性与外源基因的表达量之间没有直接关系,推测这38个雄配子突变体败育的原因主要是TDNA插入引起内源基因变异。TAILPCR 获得了22个水稻雄配子不育TDNA 插入突变体的侧翼序列,通过BLAST检索,定位了15个不同的插入位点,其中12个插入位点位于基因区或基因调控区。
The abnormal genetic segregation of more than 6,000 TDNA insertional transgenic rice lines(selectable marker gene hygromycin B phosphotransferase,hpt) was analyzed. 216 of them showed 1∶1 segregation, and 57 mutant lines were initially identified as male gametophytic sterile candidate mutants through test cross. Further multiple genetic analysis and pollen cytological observation indicated the blackdyed pollen rates of one of the 38 candidate mutations were about 50%, TDNA abnormal separation of selfing progeny due to the semisterility of pollen of transgenic plants, TDNA could be transferred only by the female gametophyte. In addition, expression levels of cry1Ac (Bt) genes tested by Enzyme Linked Immunosorbent Assay (ELISA) demonstrated their pollen sterility and foreign gene expression had no direct relationship, indiating that the abortion of the 38 male gametophytic sterile mutants was mainly attributed to endogenous gene variation caused by TDNA insertion. Flanking sequences of 22 TDNA insertional male gametophytic sterile mutants were obtained by TAILPCR. According to BLAST search, 15 different insertion sites were located, of which 12 were located in the gene or gene regulatory region.
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