小麦TaGA20ox2基因的克隆及分析

Isolation and Analysis of TaGA20ox2 Genes in Wheat

【目的】克隆小麦中的GA20-氧化酶基因并进行遗传定位,为深入研究小麦中的GA20-氧化酶基因作用机理奠定基础,同时为改良小麦的重要农艺性状提供理论依据。【方法】采用同源克隆结合BAC文库筛选的方法克隆基因,利用中国春缺失体以及国际作图群体对该基因进行遗传定位。【结果】从普通小麦中国春中分离得到TaGA20ox2的gDNA与cDNA序列,利用中国春缺失体材料将TaGA20ox2定位于3A、3B、3D染色体上,序列分析表明分别位于3A、3B、3D染色体上的TaGA20ox2-A1、TaGA20ox2-B1和TaGA20ox2-D1与水稻GA20ox2为直向同源基因,具有GA20ox2家族保守结构域;利用国际作图群体W7984×Opata85将位于3D上的基因TaGA20ox2-3定位于xfba330与xgwm664标记之间。【结论】分离获得小麦中分布于第三同源群的GA20ox2;分子标记结果结合QTL作图信息可以初步推测TaGA20ox2-3在小麦中可能是控制株高的基因。

【Objective】 The objectives of this study are to isolate full length GA20-oxidase（GA20ox2） genes from hexaploid wheat （Triticum aestivum） and locate GA20ox genes on wheat genomes,give a better understanding of the character and evolutionary relationships of GA20ox genes in wheat. 【Method】 Clone GA20ox genes from hexaploid wheat through homologous cloning method and BAC screening were used. 【Result】 Sequences analysis showed that wheat GA20-oxidase has three sequences：TaGA20ox2-A1,TaGA20ox2-B1,and TaGA20ox2-D1. Sequence alignment proved wheat GA20-oxidase genes have the highest homology with rice GA20-oxidase（80% cDNA sequence identity）. A series of Chinese Spring nulli-terasomic stocks were employed to ascertain the chromosomal location of wheat GA20-oxidase gene. The results showed that TaGA20ox2-A1,TaGA20ox2-B1,and TaGA20ox2-D1 were on wheat chromosome 3A,3B,and 3D. Using a population of recombinant inbred lines from the cross W7984×Opata85,TaGA20ox2-D1 was mapped between SSR markers xfba330 and xgwm664 on chromosome 3D,and the map distance was 4.1cM and 5.3 cM,respectively. 【Conclusion】 The full length of TaGA20ox2 was isolated and located on wheat chromosome 3A,3B and 3D. TaGA20ox2-D1 was mapped between SSR markers xfba330 and xgwm664 on chromosome 3D. In this region a plant height loci was reported. It is speculated that TaGA20ox2-D1 gene maybe control wheat height development.