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作 者 ：蔡华, 赵维萍, 许柱, 江伟, 姚运涛, 赵怡然

期 刊 ：核农学报 2016年 30卷 5期 页码：841-849

关键词：小麦；Kr1基因；kr1基因；远缘杂交不亲和；染色体步移；cDNA末端快速扩增技术；

Keywords:wheat, Kr1 gene, kr1 gene, distant hybridization incompatibility, genome walking, RACE,

摘 要 ：Kr1基因是小麦远缘杂交不亲和的主效基因。为探究Kr1基因的特性,根据已公布的Kr1基因cDNA部分序列,采用染色体步移(Genome Walking)和cDNA末端快速扩增技术(rapid amplification of cDNA ends,RACE)克隆小麦显性Kr1 基因和隐性kr1基因,并进行序列分析。结果表明,小麦Kr1 基因全长4 006 bp,含有4个外显子和3个内含子,ORF全长1 671 bp,编码557个氨基酸,可形成一条完整肽链,有基因活性,Kr1蛋白三级结构与植物S位点受体激酶具有较高的相似性。kr1基因全长3 945 bp,第3、第4外显子中因含有大量终止密码子,不能通读,表明kr1基因无基因活性。同时对小麦×黑麦、小麦×球茎大麦、小麦×玉米等不同远缘杂交系统的亲和性差异进行探讨,认为Kr1基因在小麦×玉米中失活可能与玉米转座子的插入有关。本研究结果为进一步阐明Kr1基因的功能及其作用机制奠定了基础。

Abstract:Kr1 gene is the dominant gene for distant hybridization incompatibility in wheat. In order to analyze its molecular character, the full-length sequences of the dominant and recessive Kr1 genes have been obtained by using Genome Walking and RACE PCR approaches based on its published partial cDNA sequences. The results show that, the Kr1 gene (4 006bp) contains a complete open reading frame (1 671bp) encoding 557 amino acid that could produce a complete peptide, which indicates the Kr1 gene is active. The protein tertiary structure of Kr1 is highly similar to S site receptor kinase in plants. The kr1 gene (3 945bp) contains a incomplete open reading frame with lots of termination codons in the 3^rd and 4^th exons, the read-through transcript cannot form, which indicates the kr1 gene is inactive. In addition, the difference of compatibility in wheat×rye, wheat×bulbous barley and wheat×maize was discussed in this paper, and the inactivation of Kr1 gene in wheat×maize is considered to be related to the maize transposon insertion. These results laid a foundation for further illustrating the function and working mechanism of Kr1 gene.

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