Xa1是一个能对日本白叶枯病优势小种(小种1号)产生专化性抗性的R基因,虽已有该基因克隆、表达和功能方面的研究,但对其表达调控分子机制还不很清楚。本研究利用Xa1启动子与GUS报告基因的转基因T1株系,研究了Xa1启动子的时空表达及对不同外源激素的应答特征。结果表明,Xa1启动子驱动的GUS基因在水稻根中的表达量明显高于茎和叶,且在根部的中柱区GUS的表达量明显高于周围组织;在外源MeJA作用下GUS的表达显著增强,在SA和ABA处理下也有一定程度的增强,这些结果暗示Xa1的抗病作用与其在根系中柱的组织特异性表达存在一定的相关性,MeJA对Xa1启动子的活性起重要的调控作用。 Xa1 is a R gene that can produce specific resistance to the races of Bacterial Blight (Xiao-1). Although the molecular cloning, expression and function of this gene have been studied, the molecular mechanism of its expression regulation Not yet clear. In this study, we used the transgenic T1 lines of Xa1 promoter and GUS reporter gene to study the spatial and temporal expression of Xa1 promoter and its response to different exogenous hormones. The results showed that GUS gene driven by Xa1 promoter was significantly higher than that of stem and leaf in root of rice, and the expression of GUS in the central column of root was significantly higher than that of surrounding tissues. The expression of GUS was significantly increased under the action of exogenous MeJA Enhanced and enhanced to some extent under the SA and ABA treatments. These results suggest that the disease resistance of Xa1 is related to its tissue-specific expression in the root system. MeJA plays an important regulatory role on the activity of Xa1 promoter .