大豆类受体激酶基因GmNIK的克隆与表达分析

Cloning and Analysis of Receptor-like Kinase Gene GmNIK in Soybean

大豆花叶病毒(soybean mosaic virus,SMV)病是我国大豆产区主要的病害之一,SC18是南方地区SMV流行株系。发掘对SC18株系的抗性基因对改良大豆品种的抗性具有重要意义。本实验室前期将科丰一号对SC18的抗性基因精细定位到大豆2号染色体80 kb的区间,发现该区间存在1个含亮氨酸重复结构的类受体激酶(LRR-RLK)基因GmNIK。为研究大豆GmNIK编码基因的结构和表达特性,从抗病品种科丰一号中克隆了GmNIK基因并对其序列进行生物信息学分析,利用qRT-PCR分析GmNIK在大豆不同组织和不同时期的相对表达量以及SMV诱导下的表达特性。结果表明:GmNIK完整ORF为1 866 bp,编码1个由621个氨基酸组成的具有典型LRR-RLK结构的蛋白。其氨基酸序列与已克隆的R基因的共受体具有高度同源性,与同属豆科植物的苜蓿和花生的NIK基因亲缘关系较近;GmNIK启动子区包含防御和逆境应答元件、水杨酸应答元件等多种顺式作用元件,能够响应大豆花叶病毒SC18的侵染,在大豆营养生长时期,根毛、根、茎以及叶中均有表达。SC18侵染后抗病和感病品种叶片中GmNIK的转录水平存在差异,初步预测该基因与大豆对SC18株系的抗性有关。该研究可为大豆中抗大豆花叶病毒基因的发掘以及明确抗性机制奠定部分基础。

Soybean mosaic virus(SMV)is one of the major diseases in soybean producing areas of China,and SC18 is an epidemic strain in the southern region.It is important to find the resistance related genes to SC18 strains for improving the resistance of soybean.We have mapped the related segment resistant to SC18 on the 80 kb interval of soybean chromosome 2,and found that there was a receptor-like protein kinase(LRR-RLK)gene GmNIK which contained leucine repeat.To explore the structure and expression characteristics of soybean GmNIK-coding gene,we cloned the GmNIK gene from the resistant variety Kefeng 1 and analyzed the gene with bioinformatics methods.In addition,we analyzed the relative expression of GmNIK in different tissues and different periods of soybean and detected the expression characteristics under SMV induction by qRT-PCR.The results showed that the ORF of GmNIK was 1 866 bp,and encoded a protein of 621 amino acids with a typical LRR-RLK structure.The amino acid sequence of GmNIK was highly homology with the co-receptor of the cloned R genes,and was closely related to the NIK gene in alfalfa and peanut of leguminous plants.The GmNIK promoter region contained defense and stress response element,SA response element and other cis-acting elements,which induced this gene could respond to the infection of SC18.It can be detected that the gene expressed in root hairs,roots,stems and leaves.After infected by SC18,transcription levels of GmNIK in leaves of resistant and susceptible varieties were different,it was predicted that GmNIK was related to the resistance of soybean to SC18 strain.This study lays a foundation for the identification of soybean resistance genes against soybean mosaic virus and the discovery of resistance mechanisms against soybean mosaic virus.