Isolation and chromosomal localization of cytokinin oxidase/dehydrogenase gene (TaCKX5) in wheat

Китайский. 克隆小麦的TaCKX基因并对其序列进行生物信息学分析，明确TaCKX基因在小麦基因组中的分布情况，以期为今后深入研究小麦CKX基因以及利用该基因进行小麦重要农艺性状的遗传改良奠定基础。采用同源克隆结合BAC文库筛选的方法克隆基因，通过小麦缺体-四体对其进行染色体定位。从普通小麦中国春中分离得到TaCKX5基因的gDNA和cDNA序列。分析表明，TaCKX5基因的开放阅读框为1 596 bp，编码531个氨基酸，含有CKX基因家族典型的功能位点FAD-binding domain，预测属于分泌蛋白，并具有糖基化位点。使用中国春缺体-四体将TaCKX5定位于小麦第三同源群。系统发育分析表明，CKX基因在植物中较为保守，禾谷类作物中直向同源的CKX基因很可能具有相似的特性与功能。分离获得了普通小麦TaCKX5基因全长，TaCKX5分布于小麦染色体3A、3B、3D上，与水稻OsCKX5基因直向同源。

Английский. The objectives of this study are to isolate full length CKX genes from hexaploid wheat, locate CKX gene on wheat genomes, and give a better understanding of the character and evolutionary relationships of CKX genes in wheat. A novel gene that encodes cytokinin oxidase/dehydrogenase (TaCKX5) was cloned from hexaploid wheat (Triticum aestivum) through the homologous cloning method. Sequence analysis showed that the complete ORF of TaCKX5 was 1 596 bp, and encoded a putative protein composed of 531 amino acids. Sequence alignment proved TaCKX5 shared the highest homology with rice OsCKX5 (84.9% protein sequence identity). Using TargetP program, TaCKX5 was predicted to be a secretion pathway protein, and one N-glycosylation site (NFTE) was also found with NetNGly program, implied that TaCKX5 protein may be modified posttranslationally by glycosylation. A series of Chinese Spring nulli-tetrasomic stocks were employed to ascertain the chromosomal location of TaCKX5. The result showed that TaCKX5 was on wheat chromosome 3A, 3B and 3D. From the close evolutionary relationship of othologous CKX genes, it is considered that CKX genes may be very conservative in cereals, orthologous CKX genes might have similar characters and functions. The full length of TaCKX5 was isolated and located on wheat chromosome 3A, 3B and 3D. Wheat TaCKX5 is orthologous to rice OsCKX5.