Abstract: GIGANTEA （GI） is a plant-specific nuclear protein with important role in drought stress and salt stress. In order to investigate the stress responses of GI gene in Agrostis stolonifera （AsGI）， we carried out gene cloning， subcellular localization and its expression analysis. The results showed that the complete coding region of AsGI is 3468 bp in length and it encoded 1156 amino acids. The phylogenetic tree showed that the protein encoded by the GI gene was relatively close to the evolutionary relationship with homologous proteins of Avena sativa， Lolium perenne and other graminoids. The subcellular localization results showed that the protein located in the nucleus， and the AsGI gene was expressed in both aboveground and belowground parts. The expression of the GI gene varied at different developmental stages， as the highest level in young plants and the lowest level in senescent plants. Analysis of the expression pattern with the treatment of different hormones and stresses showed that four hormones， IAA， 6-BA， GA₃ and ABA could promote the GI gene expression. Salt stress and drought stress also induced the expression of the GI gene.This study lays the foundation for further research on the function of GI gene.

Key words: GIGANTEA, Agrostis stolonifera, Expression analysis, Protein localization nucleus, Salt stress, Drought stress

摘要： GIGANTEA（GI）是一种植物特有的核蛋白，在耐旱耐盐性等方面具有重要作用。为探究匍匐翦股颖（Agrostis stolonifera）GI基因响应逆境胁迫，本研究选取匍匐翦股颖作为材料，针对匍匐翦股颖GI基因的生物学作用进行了基因克隆，生物信息学分析和亚细胞定位，同时也对其表达水平进行分析。结果表明，AsGI基因完整编码区全长3468 bp，编码1156个氨基酸。系统发育树表明GI基因编码的蛋白质与燕麦（Avena sativa）、黑麦草（Lolium perenne）等禾本科植物的同源蛋白质的进化联系十分相近。亚细胞定位结果显示该蛋白位于细胞核。GI基因在匍匐翦股颖的地上和地下部位均有表达。GI基因在幼嫩植株中表达水平最高，在衰老植株中表达水平最低。荧光定量分析不同激素处理和胁迫处理下的表达模式，IAA，6-BA，GA₃和ABA四种激素均能促进GI表达量的升高，盐和干旱胁迫处理也可诱导GI基因的表达。本研究为深入探究GIGANTEA基因的作用提供参考。

关键词: GIGANTEA, 匍匐翦股颖, 表达分析, 核定位蛋白质, 干旱胁迫, 盐胁迫