小麦细胞色素P450(TaP450)基因的克隆与序列分析

细胞色素P450是一种多功能氧化酶,在植物体内担当着生物合成、代谢解毒以及抗逆等重要功能。本研究采用RACE方法从普通小麦中同源克隆到一个新的P450基因,命名为TaP450(Genbank No.KJ541960)。该基因基因组序列全长为2 643bp,含有2个外显子和1个内含子,cDNA全长为2 033bp,含有一个1 557bp的开放读码框,推导蛋白含518个氨基酸;序列分析发现其具有保守的P450结构域,但该蛋白与已报道的小麦P450蛋白序列有较大差异,表明它是小麦P450家族的新成员;蛋白结构特征分析发现,该蛋白的分子量为57.092kD,等电点为8.63,N端具有一个含29个氨基酸的跨膜结构和一个含22个氨基酸的信号肽,亚细胞定位分析表明该蛋白属于分泌蛋白。其在小麦叶片、茎、根与种子中均有表达,但在叶片和茎中表达量最高;在胁迫处理下,该基因的表达量均上调,且在盐胁迫处理下上调尤为显著,表明该基因与盐胁迫密切相关。

Cloning and Sequence Analysis of a Cytochrome P450 ( TaP450) Gene from Wheat (Triticum aestivum L.)

Cytochrome P450 is a multifunctional enzyme, playing important roles in biosynthesis, metabolism detoxification and stress resistance in plants. Here, a P450 gene ( TaP450, Genbank No. KJ541960) were cloned using homologous based PCR combined with RACE method from common wheat. The genomic length of the cloned TaP450 was 2 643 bp with two exons and one intron. The full length cDNA was 2 033 bp, containing an open reading frame of 1 557 bp. The deduced protein had 518 amino acids (AA). Protein sequence analysis found that it had the conserved P450 domain, but its sequence composition was different from other reported wheat P450 genes, which indicated that it was a new member of P450 family in wheat. The predicted molecular weight of this protein was about 57.092 kD with the isoelectric point of 8.63. A transmembrane structure of 29 amino acids and a signal peptide of 22 amino acids were also found in its N terminus. Semi quantitative RT PCR analysis showed that this gene expressed in all the tested organs, including leaves, stems, roots and seeds, while the highest expression level was found in leaves and stems. Furthermore, TaP450 was found to be up regulated significantly under different stresses, and the highest expression level was observed under salt stress. These results indicated clearly that TaP450 might play a vital role in response to abiotic stresses, especially to salt stress in wheat. The current study isolated a new P450 gene from common wheat, which enriched the abundance of wheat P450 gene family and also shed light on revealing the biological function of this P450 gene in wheat.