矮牵牛PhNAL1b基因的克隆及功能分析

Cloning and functional characterization of PhNAL1b from Petunia×hybrida cv. Mitchell Diploid

摘要:

NAL1 (narrow leaf 1)基因在植物的分枝发育中具有重要作用，但在矮牵牛中研究较少。为了研究矮牵牛中NAL1基因的功能，本研究从矮牵牛(Petunia×hybrida cv.Mitchell Diploid)中克隆了PhNAL1b基因，该基因全长1 767 bp，编码588个氨基酸，含有Peptidase S64结构域。PhNAL1b启动子区域含有多个生长素、茉莉酸、脱落酸和光响应元件。表达分析显示PhNAL1b在根中的表达量最高，花中的表达量最低，且去顶以及细胞分裂素均能够抑制其转录。亚细胞定位分析表明PhNAL1b定位于细胞核中，为核蛋白。利用病毒诱导基因沉默(virus-induced gene silencing,VIGS)技术抑制PhNAL1b的表达，引起了矮牵牛分枝数目显著增加、株高降低。上述结果表明PhNAL1b在调控矮牵牛分枝发育中具有重要作用。本研究为揭示NAL1基因调控矮牵牛分枝发育的机理奠定了基础，并为株型改良提供了基因资源。

关键词:矮牵牛;分枝发育;PhNAL1b;表达分析;亚细胞定位;功能研究

Abstract:

Narrow leaf 1 (NAL1) plays an important role in plant branching, while little is known about the roles of this gene in petunias. In this study, PhNAL1b was cloned from Petunia×hybrida cv. Mitchell Diploid, with a total length of 1 767 bp, encoding a protein composed of 588 amino acid residues and containing the peptidase S64 domain. The PhNAL1b promoter region contained several elements involved in the responses to auxin, jasmonic acid, abscisic acid, and light. The expression analysis showed that PhNAL1b had the highest expression level in roots and the lowest expression level in flowers, and its transcription could be inhibited by decapitation and cytokinin. The subcellular localization analysis showed that PhNAL1b was located in the nucleus and was a nuclear protein. Virus-induced gene silencing was employed to downregulate the expression of PhNAL1b, which resulted in significant increases in branch number and plant height. The results indicated that PhNAL1b played an important role in regulating the branching of petunias. This study lays a foundation for revealing the mechanism of NAL1 in regulating branch development and provides genetic resources for plant architecture improvement.

Key words:Petunia hybrida;shoot branching;PhNAL1b;expression analysis;subcellular localization;functional research