普通小麦中一氧化氮相关因子 (TaNOA) 编码基因的克隆和分子生物学分析

Molecular cloning and preliminary analysis of TaNOA in common wheat

摘要:

一氧化氮是动植物体内重要的信号分子。本研究利用同源克隆技术从六倍体普通小麦中获得一个一氧化氮相关因子 (TaNOA) 编码基因的全长基因组和cDNA克隆。该基因具有13个外显子和12个内含子，与拟南芥以及水稻中同源基因结构相似。根据cDNA推导的氨基酸序列与拟南芥AtNOA1的序列一致性达60％以上，具备P-环GTPase G4-G5-G1-G2-G3的排列特征和保守的序列。对其中2个内含子的测序分析表明在六倍体小麦中TaNOA至少有3个成员。进一步用中国春小麦缺体-四体材料将这3个TaNOA基因成员分别定位在第六同源群的6A、6B和6D染色体上，本研究中获得的成员定位于6B染色体上，因此将其命名为TaNOA-B1。原生质体表达实验表明，TaNOA-B1可能定位在线粒体中。TaNOA基因在小麦根、叶片中表达较高，在幼穗和小花中有少量表达，茎中几乎检测不到表达。TaNOA的转录本水平还因脱落酸或盐处理而上升，表明它可能参与小麦对非生物胁迫的反应。本研究为进一步克隆六倍体小麦中TaNOA的其他成员及研究该基因在小麦中的功能奠定了基础。

Abstract:

Nitric oxide (NO) is an important signaling molecule with diverse physiological functions in both animal and plant cells. In this work, we isolated the full-length cDNA and genomic DNA sequences of TaNOA-B1 encoding a putative NO associated (NOA) factor in common wheat. Bioinformatic analysis showed that TaNOA-B1 possessed a similar intron/exon structure as its orthologous genes in Arabidopsis and rice. The amino acid sequence deduced from TaNOA-B1 was more than 60% identitical to those of Arabidopsis and rice NOA1 proteins. The primary structure of TaNOA-B1 contained the zinc finger and P-loop GTPase motifs conserved in Arabidopsis and rice NOA1 proteins. There existed at least three NOA gene members in common wheat, which were mapped to homoeologous group six chromosomes 6A, 6B and 6D, respectively. TaNOA-B1 investigated in this work was located on chromosome 6B. The transcripts of TaNOA members were found mainly in leaves. TaNOA-B1-GFP fusion protein may be located in mitochondria. TaNOA transcript level was up-regulated by abscisic acid (ABA) or NaCl treatments, indicating that TaNOA might be involved in wheat responses to abiotic stresses.