A paralog of the MtN3/saliva family recessively confers race-specific resistance to Xanthomonas oryzae in rice
A paralog of the MtN3/saliva family recessively confers race-specific resistance to Xanthomonas oryzae in rice
复制标题
MtN3/唾液家族的旁系同源物隐性地赋予水稻对米黄单胞菌的种族特异性抗性
DOI：
10.1111/j.1365-3040.2011.02391.x
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发表时间：
2011-11-01
影响因子：
7.3
通讯作者：
Wang, Shiping
中科院分区：
文献类型：
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作者：
Liu, Qinsong;Yuan, Meng;Wang, Shiping
在已鉴定的34个水稻主要病害抗性基因中，约有三分之一的基因对黄单胞菌不同菌株具有小种特异性抗性。水稻白叶枯病致病基因Xoo为隐性基因。然而，到目前为止，只有两个隐性抗性基因被表征。在这里，我们报告的另一个隐性抗Xoo抗性基因，xa 25的特性。Xa 25位于第12号染色体的着丝粒区，通过抑制Xoo的生长，在幼苗和成虫阶段介导对Xoo菌株PXO 339的小种特异性抗性。它编码MtN 3/唾液家族的蛋白质，其在包括哺乳动物在内的真核生物中普遍存在。将显性Xa 25转化到携带隐性Xa 25的抗性水稻品系中，消除了其对PXO 339的抗性。隐性等位基因Xa 25与显性等位基因Xa 25的编码蛋白有8个氨基酸的差异。PXO 339能迅速诱导显性Xa 25基因的表达，而非隐性Xa 25基因的表达，而其他Xoo菌株则不能。xa 25编码蛋白的性质及其在水稻-Xoo互作中与其感病等位基因的表达模式的比较表明，xa 25介导的抗性机制似乎与大多数特征R蛋白所赋予的机制不同。
Approximately one third of the identified 34 rice major disease resistance (R) genes conferring race-specific resistance to different strains of Xanthomonas oryzae pv. oryzae (Xoo), which causes rice bacterial blight disease, are recessive genes. However, only two of the recessive resistance genes have been characterized thus far. Here we report the characterization of another recessive resistance gene, xa25, for Xoo resistance. The xa25, localized in the centromeric region of chromosome 12, mediates race-specific resistance to Xoo strain PXO339 at both seedling and adult stages by inhibiting Xoo growth. It encodes a protein of the MtN3/saliva family, which is prevalent in eukaryotes, including mammals. Transformation of the dominant Xa25 into a resistant rice line carrying the recessive xa25 abolished its resistance to PXO339. The encoding proteins of recessive xa25 and its dominant allele Xa25 have eight amino acid differences. The expression of dominant Xa25 but not recessive xa25 was rapidly induced by PXO339 but not other Xoo strain infections. The nature of xa25-encoding protein and its expression pattern in comparison with its susceptible allele in rice-Xoo interaction indicate that the mechanism of xa25-mediated resistance appears to be different from that conferred by most of the characterized R proteins.