植物抗病基因结构特征及其类似序列的研究进展

Update of resistance genes and resistance gene analogs in plants

植物抗病基因的克隆一直为植物遗传学家和病理学家所关注。克隆的抗病基因在氨基酸水平上表现出一定程度的相似性， 在一些区段高度保守， 如 Ｎ Ｂ Ｓ、 Ｌ Ｒ Ｒ、激酶、 Ｌ Ｚ等。这些保守序列， 不仅有助于对抗病基因的分类及其作用机理的理解， 而且为抗病基因克隆提供了一条新途径。根据这些保守序列合成 Ｐ Ｃ Ｒ 引物， 在许多植物中已扩增出大量的抗病基因类似序列 （ Ｒ Ｇ Ａ）。遗传作图表明 Ｒ Ｇ Ａ 与抗病性密切相关。对 Ｒ Ｇ Ａ 与 Ｒ 基因的关系及 Ｒ Ｇ Ａ 的基因组分布一并进行了讨论。

Molecular cloning disease resistance(R)genes attracts much attention of plant geneticists and pathologists.Cloned R genes showed considerable similarities at amino acid level.Some conserved domains,such as leucine rich repeats(LRR),leucine zipper(LZ),nucleotide binding site(NBS),serine/theorine kinase,have been revealed.The conserved domains not only provide insight on mechanism of R gene action and information for R gene classification,but a novel approach to isolate new R genes as well.Using the PCR primers based on the conserved domains,large quantity of R gene analogs(RGA)have been amplified from many plant genomes.Genetic analyses indicated the close association of RGA with disease resistances.The relationship with R genes and genome organization of RGA were also discussed.