Cloning and Characterization of R3b; Members of the R3 Superfamily of Late Blight Resistance Genes Show Sequence and Functional Divergence
Cloning and Characterization of R3b; Members of the R3 Superfamily of Late Blight Resistance Genes Show Sequence and Functional Divergence
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DOI：
10.1094/mpmi-11-10-0276
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发表时间：
2011-10-01
影响因子：
3.5
通讯作者：
Vossen, Jack H.
中科院分区：
文献类型：
--
作者：
Li, Guangcun;Huang, Sanwen;Vossen, Jack H.
大规模抗性基因叠加被认为是为马铃薯晚疫病的常规育种和转基因育种提供持久抗性的最有前途的方法之一。马铃薯染色体XI上的R3复合基因座是天然R基因堆叠的一个例子，因为它包含两个紧密连锁的R基因（R3 a和R3 b），对致病疫霉具有不同的抗性特异性。在这里，我们报告的位置克隆的R3 b。瞬时和稳定的转换敏感的烟草和马铃薯植物表明，R3 b赋予完全抗不兼容的致病疫霉菌株。R3 b编码一个卷曲螺旋核苷酸结合位点富含亮氨酸的重复蛋白，与R3 a位于同一R3簇中，具有82%的核苷酸同一性。R3 b基因特异性识别Avr 3b，Avr 3b是一种新鉴定的致病疫霉无毒因子。R3 b不识别Avr 3a，即R3 a的相应无毒基因，这表明，尽管R3 b和R3 a具有高序列相似性，但它们具有明显不同的识别特异性。除了染色体IV上的Rpi-mcd 1/Rpi-blb 3基因座之外，染色体XI上的R3基因座是具有识别致病疫霉不同小种的多个基因的R基因簇的第二个实例。
Massive resistance (R) gene stacking is considered to be one of the most promising approaches to provide durable resistance to potato late blight for both conventional and genetically modified breeding strategies. The R3 complex locus on chromosome XI in potato is an example of natural R gene stacking, because it contains two closely linked R genes (R3a and R3b) with distinct resistance specificities to Phytophthora infestans. Here, we report about the positional cloning of R3b. Both transient and stable transformations of susceptible tobacco and potato plants showed that R3b conferred full resistance to incompatible P infestans isolates. R3b encodes a coiled-coil nucleotide-binding site leucine-rich repeat protein and exhibits 82% nucleotide identity with R3a located in the same R3 cluster. The R3b gene specifically recognizes Avr3b, a newly identified avirulence factor from P. infestans. R3b does not recognize Avr3a, the corresponding avirulence gene for R3a, showing that, despite their high sequence similarity, R3b and R3a have clearly distinct recognition specificities. In addition to the Rpi-mcd1/Rpi-blb3 locus on chromosome IV, the R3 locus on chromosome XI is the second example of an R-gene cluster with multiple genes recognizing different races of P. infestans.