摘要： 为了研究非生物胁迫处理下小麦抗坏血酸过氧化物酶（APX）的作用，以小麦百农207为试验材料，根据小麦APX基因序列，采用RT-PCR技术对小麦APX基因进行克隆、生物信息学分析及组织表达模式分析；对小麦进行非生物胁迫处理，分析小麦APX基因在环境胁迫条件下的表达特征。结果表明，TaAPX基因包含876 bp的开放阅读框，编码1个291个氨基酸组成的蛋白质，分子质量为31.73 ku，等电点为7.74，分子式C₁₄₁₇H₂₂₄₆N₃₉₄O₄₂₃S₅，TaAPX可能是两性蛋白，无信号肽，为非分泌蛋白。蛋白质序列比对和进化树分析表明，小麦与大麦的APX编码蛋白的氨基酸全长序列相似性最高达到97.25%，亲缘关系最近。实时荧光定量PCR分析表明，TaAPX在小麦幼根、茎、茎节、幼叶、叶鞘、雌蕊和雄蕊中均有表达，其中在幼叶中表达量最高，其次是茎、茎节，在幼根、叶鞘中表达量较低，在雌、雄蕊中表达量最低。在非生物胁迫条件下该基因受干旱、低温胁迫表达增强，而在NaCl胁迫和渗透胁迫下表达降低。综上，获得了TaAPX基因的编码区序列，分析发现其响应干旱、低温和盐等逆境胁迫，提示该基因可能与小麦抗逆境机制密切相关。

关键词: 小麦, APX, 基因克隆, 表达分析, 逆境胁迫

Abstract: The effect of ascorbic acid peroxidase (APX) in wheat under abiotic stress was studied by using the wheat of Bainong 207 as experimental material. According to the wheat TaAPX gene sequence, TaAPX was cloned by PCR, bioinformatics and tissue expression pattern analyzed. Bioinformatics and tissue expression pattern analysis were used to analyze the expression characteristics of TaAPX under abiotic stress. The results showed that TaAPX contained 876 bp open reading frame, encoded a protein composed of 291 amino acid. The molecular mass of TaAPX was 31.73 ku, the molecular formula was C₁₄₁₇H₂₂₄₆N₃₉₄O₄₂₃S₅ and the isoelectric point was 7.74, which might be a signal-free peptide, amphoteric protein and non-secretory protein. By comparing the APX protein sequences of wheat and barley and analyzing the evolutionary tree, it concluded that they had the closest genetic relationship with barley, and the maximum similarity of the full-length amino acid sequence of the coding protein was 97.25%.The tissue expression profiles detected by RT-qPCR indicated that it was differently expressed in the young roots, stems, stem nodes, young leaves, leaf sheaths, pistil and stamens. The expression level of TaAPX were highest in the young leaves, followed by that in the stem and stem node, the lowest expression level was found in the pistil and stamen. Under abiotic stress, the TaAPX expression was enhanced under drought and low temperature stress, but decreased under NaCl stress and osmotic stress.The coding sequence of TaAPX gene was obtained, and this gene responded to saline, drought and low temperature stress, suggesting that it may be closely related to anti-stress mechanism in wheat.

Key words: Wheat, APX, Gene cloning, Expression analysis, Adversity stress

中图分类号: 

• S512.03