Abstract:

【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.

Key words: wheat, GA20-oxidase, gene cloning, genetic mapping