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百香果NBS-LRR类抗病基因同源序列的克隆与分析

Cloning and Analysis of NBS-LRR Resistance Gene Analogs of Passion Fruit

  • 摘要: 挖掘植物内源抗病基因,是开展抗病新品种选育的重要基础。以黄金百香果钦果9号为试验材料,基于已知植物NBS-LRR类抗病基因的保守结构域设计简并引物,克隆其基因组中NBS-LRR类抗病基因同源序列(RGA)并挖掘潜在抗病基因。结果表明,钦果9号的NBS-LRR类抗病基因可分为TIR型与non-TIR型两类:TIR-NBS-LRR亚型共12条,对应编号为QRGA1~QRGA12;non-TIR-NBS-LRR亚型共4条,对应编号为QRGA13~QRGA16。聚类分析显示:QRGA1~QRGA12与已报道的烟草抗TMV(烟草花叶病毒)基因N、亚麻抗病基因L6聚为同一类群,其同源性为86%;QRGA13~QRGA16与水稻抗白叶枯病基因Xa-1、拟南芥抗丁香假单胞菌基因RPM1聚为一个分支,其同源性为63%。尤其是QRGA1~QRGA12序列,经比对发现其编码的氨基酸与多种植物的抗TMV蛋白、抗RPV1蛋白相似度极高,具备潜在的研究与应用价值。研究结果可为百香果抗病基因的挖掘及后续应用提供支撑。

     

    Abstract: Discovering endogenous plant resistance genes is a critical preliminary foundation for breeding disease-resistant varieties. In this study, degenerate primers were designed based on the conserved domains of known plant NBS-LRR resistance genes, and Passiflora edulis f. flavicarpa ‘Qinguo 9' was used as the experimental material to clone NBS-LRR resistance gene analogs(RGA) from its genome. The results showed that the NBS-LRR resistance genes of this cultivar could be divided into two types: TIR type and non-TIR type. Among them, there were 12 TIR-NBS-LRR subtypes(designated QRGA1 to QRGA12) and 4 non-TIR-NBS-LRR subtypes(designated QRGA13 to QRGA16). Phylogenetic analysis revealed that QRGA1~QRGA12 clustered with the reported tobacco TMV-resistance gene N and flax resistance gene L6, with a homology of 86%. In contrast, QRGA13~QRGA16 clustered with rice bacterial blight-resistance gene Xa-1 and Arabidopsis pseudomonas syringae-resistance gene RPM1, with a homology of 63%. Notably, the amino acids encoded by QRGA1~QRGA12 showed high similarity to TMV-resistant proteins and RPV1-resistant proteins from multiple plant species, indicating their potential research and application value. The findings of this study provide support for the discovering and subsequent application of resistance genes in Passiflora edulis.