一个新水稻根尖特异表达启动子的分离与鉴定

Isolation and Characterization of a Novel Root Tip-specific Promoter in Rice

为了挖掘水稻中的根系特异表达启动子,通过生物信息学分析和RT-PCR验证获得1个在根尖特异表达的水稻基因Os04g24469。用分离出的该基因上游启动子,与GUS报告基因构建表达载体并转化到受体水稻日本晴中。通过对转基因后代中不同组织器官中的GUS活性检测,证明该启动子在水稻根尖特异性强烈表达。结合该根尖特异表达启动子,我们分析了一个在水稻地上部及地下部都组成表达的功能基因OsSRG对水稻根系发育的贡献。该基因的缺失导致水稻突变体srg根系变短,而利用分离的根尖特异性Os04g24469启动子在根尖驱动GUS-OsSRG的表达,能回复突变体根系生长,表明OsSRG在根尖的表达足以影响水稻根系生长,而在地上部的表达与根系发育无关。本研究表明Os04g24469启动子是一个水稻根尖特异表达启动子,利用该启动子可以控制目标基因在水稻根尖特异表达,可用于水稻根系基因功能的研究。

To obtain the root-specific promoters in rice,a root-specific gene Os04g24469was selected by analyzing the public microarray data and further confirmed by RT-PCR.To determine the expression pattern of the novel promoter,the putative promoter was isolated and fused with the GUSreporter gene to transform into the rice variety Nipponbare.Subsequent GUS staining of the transgenic plants showed that the Os04g24469promoter was only activated in rice root tip.Using this root tip-specific promoter,we characterized the function of a ubiquitously expressed gene OsSRGin root development.The absence of OsSRGled to a short root phenotype in the srgmutant,the root tip-specific expression of GUS-OsSRGin srgplants significantly reversed the root growth defect,indicating that the expression of OsSRGin root tip,not in shoot,is important for root development in rice.The present study showed that Os04g24469promoter is highly active in the root tip and can be useful for the root tip-specific expression of target genes and gene function analysis in rice root.