遗传转化KN1基因促进毛果杨外植体再生

Promotion on Regeneration of Explants with Genetic Transformation of KN1 Gene in Populus trichocarpa

已有研究表明玉米同源异形盒(homeobox)基因Knotted1(KN1)超量表达会导致转基因烟草、拟南芥和番茄等植物中细胞分裂素含量增加,提高转化效率。由于木本植物遗传转化困难,且毛果杨可作为木本植物研究的模式植物,因此,本研究利用农杆菌介导法,将35S启动子驱动的玉米KN1(35S::KN1)基因导入毛果杨,并分析KN1基因表达对毛果杨再生率的影响。研究结果表明,经GUS组织化学染色及PCR分子鉴定,KN1基因已经成功导入毛果杨幼苗;KN1基因对毛果杨外植体愈伤诱导率影响不明显,但单个外植体芽诱导率比对照高0.96倍,毛果杨的再生频率明显提高;与移栽成活的野生对照植株相比,转化KN1基因植株出现叶片变小,叶色变深,在叶片边缘产生裂片,分枝增加,无顶端优势等特殊表型。本研究中KN1基因引起转化植株表型变化,因此在毛果杨的遗传转化中,可作为一种有效的正向选择标记基因。

The finished studies have shown that overexpression of homeobox gene Knotted1（KN1） of maize could increase cytokinins content in transgenic tobacco,Arabidopsis,tomato and other plants and also improved the transformation efficiency.Because there were a lot of difficulties on genetic transformation of xylophyta plant and Populus trichocarpa was as a model xylophyta plant,we transformed 35S：：KN1 into Populus trichocarpa via Agrobacterium-mediated method and analyzed the influence of KN1 gene expression on the explant of Populus trichocarpa regeneration rate.The results of GUS histochemical stainning and PCR molecular analysis showed that KN1 gene was already transformed into Populus trichocarpa,and KN1 gene expression didn＇t show a significant effect on the induction rate of explant callus,however,the induction rate of buds was 0.96 times higher than the control.Therefore,the expression of KN1 gene obviously improved the regeneration rate.Compared to the wild control plants,KN1 transformed plants showed special characteristics such as smaller leaves,denser leaf color,bothridium at the edge of leaves,increased branches and no apical dominance,and so on.The results suggested that KN1 gene could be used as an effective positive selectable marker gene in Populus trichocarpa genetic transformation due to the phenotypic variation caused by KN1 expression.