水稻抗白葉枯病基因Xa3/Xa26 是一個(gè)多基因家族的成員。為了檢測(cè)該基因家族中是否可能存在其他抗病基 因和這些成員可能發(fā)揮功能的部位,系統(tǒng)研究了Xa3/Xa26 基因家族成員的表達(dá)模式。將秈稻品種明恢63、特青、93211和粳稻品種日本晴中Xa3/Xa26 基因家族的13個(gè)成員(MRKa、Xa3/Xa26、MRKc、TRKa、TRKb、TRKc、9RKa、9RKb、9RKe、NRKa2、NRKe、NRKf1和NRKf3)的啟動(dòng)子與編碼綠色熒光蛋白(GFP)的報(bào)告基因進(jìn)行融合表達(dá)，通過(guò)農(nóng)桿菌介導(dǎo)的遺傳轉(zhuǎn)化方法將不同啟動(dòng)子調(diào)控的報(bào)告基因分別導(dǎo)入水稻。通過(guò)檢測(cè)GFP表達(dá)，分析這些家族成員的組織特異性表達(dá)模式，發(fā)現(xiàn)Xa3/Xa26 基因家族成員的表達(dá)模式基本一致，主要集中在水稻各組織的維管束細(xì)胞及其周圍細(xì)胞中。Xa3/Xa26 基因家族的表達(dá)模式與抗維管束病原菌(如白葉枯病菌)基因的功能非常吻合。這種表達(dá)模式為寄主進(jìn)化過(guò)程中，從該家族不斷產(chǎn)生新的抗病基因提供了重要信息。
T he bacter ial blight resistance gene Xa3 / Xa26 belongs to a multig ene family. T o pr edict whether this mult-i g ene family contains other r esistance g ene( s) and the putative function sites of these g enes, the expr ession patterns of the family members were analyzed. T he promoters of 13 X a3/ X a26 family members, MRKa, Xa3 / Xa26 , MRK c, T RKa, TRK b, T RK c, 9RK a, 9RK b , 9RK e, NRK a2 , NRK e, NRK f 1, and NRK f3 isolated fr om indica rice varieties Minghui 63, T eqing and 93-11 and japonica rice variety Nipponbare, w ith the reporter gene encoding green fluor escent pr otein ( GFP) w er e connected and these constructs were separately transfer red into r ice by A grobacter ium-mediated transfo rmation. Exam-i nation of GF P expression in transgenic plants showed that the Xa3 / Xa26 family members had similar expr ession pattern. These members mainly ex pressed in the cells o f vascular sy stems and cells around vascular systems in differ ent tissues of r ice. The expressional character istic of Xa3 / Xa26 family members fits the function for the genes confer ring r esistance to Xanthomonas ory z ae pv. or yz ae, the vascular pathog en. The expressional characteristic also prov ided basis for continued generation of new disease resistance genes from this family dur ing evolution.