一种水稻愈伤组织特异性启动子的克隆及其应用

筛选标记基因是一种用于植物遗传转化后阳性转化子筛选的有效手段,但目前介导标记基因表达均采用组成性启动子.这些启动子虽然在植物遗传转化得到了广泛应用,但由于是组成性表达,在转基因的生物安全性存在标记基因的安全性担忧.为了克服这一缺点,本文从水稻基因组内克隆了水稻半胱氨酸蛋白酶基因(Cyctein protease,CP)的启动子,通过gus转基因的验证,该启动子只在愈伤组织表达,不在水稻根、茎、叶等组织表达,为愈伤组织特异性表达启动子(Callus-specific Promoter,CSP).将该启动子用于介导筛选性标记基因的表达,通过对筛选性标记基因潮霉素磷酸转移酶基因(hpt)的密码子优化,明显提高了CP启动子在水稻转基因选择的转化效率,质粒转化效率和阳性植株率均达到了pCAMBIA1301的35S启动子介导标记基因hpt的选择效果.

Cloning and Application of a Callus-Specific Promoter of Rice

Selective marker gene is an effective tool used for the selection of positive callus of plant transformation.Currently,almost all of selective marker genes are driven by constitutive promoters.Although these promoters are widely used for plants transformation,the constitutive expressions of marker gene in transgenic plants have potential safety concern.To solve this problem,we cloned a callus-specific promoter from rice CP(Cyctein protease) gene.Through transgenic approach using gus as a reporter gene,it was easy to find that CP promoter was specifically expressed in callus,but not in roots,stem,leaves or any other tissues.So we designated it as a Callus-specific Promoter(CSP).To improve the selective efficiency,CP promoter was fused to a codon optimized selective marker gene hpt and the selective efficiency of CP promoter was obviously improved.The transformation efficiency and positive calli resisted to hpt gene were nearly the same as that of pCAMBIA1301,which the marker gene hpt was driven by 35S promoter.Our results established a selective marker system that utilized CP promoter mediated hpt gene expression.This system has independent intellectual property and provides a new way for the security guarantees of transgenic plants.