水稻抗白叶枯病基因Xa3/Xa26家族成员的表达模式分析

 水稻抗白叶枯病基因Xa3/Xa26是一个多基因家族的成员。为了检测该基因家族中是否可能存在其他抗病基因和这些成员可能发挥功能的部位，系统研究了Xa3/Xa26基因家族成员的表达模式。将籼稻品种明恢63、特青、93 11和粳稻品种日本晴中Xa3/Xa26基因家族的13个成员（MRKa、Xa3/Xa26、MRKc、TRKa、TRKb、TRKc、9RKa、9RKb、9RKe、NRKa2、NRKe、NRKf1和NRKf3）的启动子与编码绿色荧光蛋白（GFP）的报告基因进行融合表达，通过农杆菌介导的遗传转化方法将不同启动子调控的报告基因分别导入水稻。通过检测GFP表达，分析这些家族成员的组织特异性表达模式，发现Xa3/Xa26基因家族成员的表达模式基本一致，主要集中在水稻各组织的维管束细胞及其周围细胞中。Xa3/Xa26基因家族的表达模式与抗维管束病原菌（如白叶枯病菌）基因的功能非常吻合。这种表达模式为寄主进化过程中，从该家族不断产生新的抗病基因提供了重要信息。

Analysis on Expression Patterns of the Family Members of Rice Bacterial Blight Resistance Gene Xa3 /Xa26

The bacterial blight resistance gene Xa3/Xa26 belongs to a multigene family.To predict whether this multigene family contains other resistance gene(s)and the putative function sites of these genes,the expression patterns of the family members were analyzed.The promoters of 13 Xa3/Xa26 family members,MRKa,Xa3/Xa26,MRKc,TRKa,TRKb,TRKc,9RKa,9RKb,9RKe,NRKa2,NRKe,NRKf1,and NRKf3 isolated from indica rice varieties Minghui 63,Teqing and 93-11 and japonica rice variety Nipponbare,with the reporter gene encoding green fluorescent protein(GFP)were connected and these constructs were separately transferred into rice by Agrobacterium-mediated transformation.Examination of GFP expression in transgenic plants showed that the Xa3/Xa26 family members had similar expression pattern.These members mainly expressed in the cells of vascular systems and cells around vascular systems in different tissues of rice.The expressional characteristic of Xa3/Xa26 family members fits the function for the genes conferring resistance to Xanthomonas oryzae pv.oryzae,the vascular pathogen.The expressional characteristic also provided basis for continued generation of new disease resistance genes from this family during evolution.