紫花苜蓿β-1,3-葡聚糖酶基因同源克隆与序列变异分析  

Isolation and Variation of the Gnomic Coding Sequences of beta-1,3-glucanase Genes in Alfalfa

作　　者：高建明 桂枝 卢树昌 GAO Jian-ming;GUI Zhi;LU Shu-chang(College of Agronomy,ResourceSand Environmental Science,Tianjin Agricultural University,Tianjin 300384,P.R.China)

机构地区：[1]天津农学院农学与资源环境学院

出　　处：《西部林业科学》2019年第5期56-62,共7页Journal of West China Forestry Science

基　　金：天津市高校“学科领军人才培养计划”项目(J01009030705)

摘　　要：β-1,3-葡聚糖酶是植物重要的防卫蛋白之一。采用同源克隆法,从16个紫花苜蓿品种的集群DNA中分离到3个苜蓿β-1,3-葡聚糖酶基因的部分基因组编码序列,分别对应于蒺藜苜蓿3个不同的β-1,3-葡聚糖酶基因,并命名为β-1,3-葡聚糖酶基因1、β-1,3-葡聚糖酶基因2和β-1,3-葡聚糖酶基因3。其中,β-1,3-葡聚糖酶基因2和苜蓿β-1,3-葡聚糖酶基因3及其蒺藜苜蓿对应基因与包括β-1,3-葡聚糖酶基因1在内的其他豆科同类基因遗传距离较大。序列变异分析显示,β-1,3-葡聚糖酶基因2的SNP位点间平均距离为255bp,DNA和氨基酸序列均非常保守,表明其在进化中受到了强烈的选择压力。β-1,3-葡聚糖酶基因1的SNP位点间平均距离虽然较小(31bp),但其全部21个SNP位点均为同义SNP,同时,测序片段仅发现了10个单倍型,远远小于其理论单倍型数目(221)。这表明β-1,3-葡聚糖酶基因1的氨基酸序列高度保守,在功能上非常重要,少量单倍型的存在是为了调节其表达,以使苜蓿适应多种内、外部环境条件。Beta-1,3-glucanase geneSare one of the most important defensive proteinSin plant.ThiSstudy aimed to isolate the genomic coding sequenceSof beta-1,3-glucanase geneSby a homology-based cloning method using the bulked DNA from16 cultivarSaSmaterialSin alfalfa( Medicago sativa ).Consequently,the part genomic coding sequenceSof a total of3 beta-1,3-glucanase geneSwere isolated,and each of these3 geneShad a corresponding homologouSbeta-1,3-glucanase gene from Medicago truncatula .They were named aSbeta-1,3-glucanase gene1,beta-1,3-glucanase gene2 and beta-1,3-glucanase gene3,respectively.Cluster analysiSshowed that beta-1,3-glucanase gene2,beta-1,3-glucanase gene3,and the corresponding geneSof these two geneSin Medicago truncatula clearly diverged from beta-1,3-glucanase geneSfrom other Fabaceae plantSand beta-1,3-glucanase gene1 found.Sequence vibration analysiSshowed beta-1,3-glucanase gene2 had an high average inter-SNP distance with a value of225 bp,indicating thiSgene waSvery conserved and thuSsuffered from a strong evolutionary selection pressure. beta-1,3- glucanase gene1 possessed an low average inter-SNP distance with a value of31bp,but all of21SNP siteSfrom thiSgene were synonymous.Furthermore,only a total of10 haplotypeSwere detected for the fragment sequenced from beta-1,3-glucanase gene1,which waSfar lesSthe theoretical haplotype number(221 ).ThiSindicated that beta-1,3-glucanase gene1 also waSvery conservative and had a very important function in alfalfa genome.Preserving a little of haplotypeScould help to regulate the expression of thiSgene,therefore enhance the adaptability of alfalfa to a variety of internal and external environmental conditions.

关 键 词：紫花苜蓿 Β-1 3-葡聚糖酶 同源克隆 基因组序列分离 单核苷酸多态性 

分 类 号：S541.1[农业科学—作物学]