刘选明 孙孟思 李新梅 贺热情 屈丽娜 唐冬英 赵小英

摘 要：FOF2为F-box蛋白家族成员，其生物学功能尚不清楚.采用实时荧光定量PCR和生理學实验相结合的方法，对FOF2基因的表达模式及其在拟南芥抗盐和冷胁迫响应中的作用进行了分析.研究发现，FOF2在拟南芥根、茎生叶和果荚中表达较高，并且其表达受盐和冷胁迫诱导.FOF2过表达株系对盐胁迫敏感，与野生型相比种子萌发率低、幼苗主根较短；相反，fof2突变体对盐胁迫的敏感性则减弱.FOF2过表达和缺失突变体种子萌发对冷胁迫无响应，但其主根在冷处理中分别比野生型短或者长.盐处理下，FOF2过表达株系中盐胁迫反应相关基因的表达量显著降低，fof2突变体中则升高；冷处理下，FOF2过表达株系中冷胁迫反应相关基因的表达量显著升高，fof2突变体中则降低.结果表明，FOF2在植物抗盐胁迫响应中起负调控作用，在抗冷胁迫响应中则可能起正调控作用.

关键词：功能分析；FOF2；F-box基因；逆境胁迫；拟南芥

中图分类号：Q94 文献标志码：A

Abstract：FOF2 is one of the F-box protein family members and its biological function remains unclear. The expression patterns and function of FOF2 in response to salt and cold stress in Arabidopsis were analyzed by real-time quantitative PCR and physiological method. The results showed that FOF2 was highly expressed in root， cauline leaf and silique in Arabidopsis， and its transcriptional level was induced by salt and cold stress. The seed germination and root elongation of FOF2 overexpression lines were hypersensitive to salt stress， while the fof2 mutant showed reduced sensitivity to salt stress compared with wild type. The seed germination of both the FOF2 overexpression lines and fof2 mutant showed no phenotype in response to cold， but their primary root length was shorter or longer than the wild type plant during cold stress， respectively. The salt stress responsive marker genes were down-regulated in FOF2 overexpression lines， but up-regulated in fof2 mutant under salt stress. The cold stress responsive marker genes were up-regulated in FOF2 overexpression lines， but down-regulated in fof2 mutant under cold stress. These results indicate that the FOF2 plays a negative role in salt tolerance， but positive role in cold tolerance in Arabidopsis.

Key words：functional analysis； FOF2； F-box gene； abiotic stress； Arabidopsis

在拟南芥基因组中约有700个基因编码F-box蛋白家族.F-box蛋白家族的共同特点是在氨基酸序列中含有一段F-box基序，它们在植物生长发育过程中发挥了重要调控作用[1-5].除了植物，F-box蛋白在动物中也起到了重要的作用，如控制骨和软骨的形成[6].F-box蛋白通常通过形成SCF复合物行使功能[7].SCF复合物包含4个亚基分别为Cullin、SKP1、RBX1和F-box蛋白[8]，每个 F-box蛋白家族成员的 N端都至少含 1个大约40～50个保守氨基酸的F-box基序， 并与Skp1结合； C端是结构不同的蛋白-蛋……