洋葱AcSCL4的克隆及其功能分析

Cloning and function analysis of AcSCL4 in onion

【目的】初步探讨AcSCL4在洋葱成花中的功能,为解析洋葱成花分子调控机制提供理论基础。【方法】以长日生态型洋葱品系SB2为试验材料,根据已有的洋葱转录组数据,通过qRT-PCR筛选目的基因AcSCL4后进行基因克隆,并对其进行生物信息学分析;构建AcSCL4基因的过表达载体pB221-3300-AcSCL4并转化农杆菌,采用花序浸染法浸染拟南芥,并对T_(3)代纯系转基因植株进行表型分析和开花相关基因表达量分析。【结果】洋葱AcSCL4基因CDS长1515 bp,编码504个氨基酸;AcSCL4蛋白N端高度变异,C端有GRAS结构域。聚类分析发现,AcSCL4与石刁柏和棉花的SCL4蛋白亲缘关系较近。与野生型拟南芥相比,AcSCL4过表达植株表现晚花表型。荧光定量PCR结果表明,与野生型拟南芥相比,AcSCL4过表达植株开花调控基因CO和FT的表达量极显著下降。【结论】AcSCL4通过调控CO及FT基因表达来抑制洋葱开花。

【Objective】The function of AcSCL4 in flowering was preliminarily studied to provide basis for understanding molecular regulation mechanism of onion flowering regulation.【Method】AcSCL4 was identified by qRT-PCR and bioinformatics analysis based on the transcriptome data of a long-day onion inbred line SB2.The AcSCL4 overexpression vector pB221-3300-AcSCL4 was constructed and transformed to Arabidopsis by Agrobacterium tumefaciens.Homozygous Arabidopsis transgenic lines(T_(3))were used for further phenotypic characterization and genes expression identification.【Result】The cDNA of AcSCL4 gene was 1515 bp and encoded 504 amino acids.AcSCL4 had conserved GRAS domain at the C terminus and was highly variable at the N terminus.AcSCL4 was phylogenetically closer to the SCL4 of Asparagus officinalis and Gossypium hirsutum.Overexpression of AcSCL4 delayed the flowering time of wild-type Arabidopsis.The expressions of CO and FT were significantly decreased in AcSCL4 overexpression transgenic lines.【Conclusion】AcSCL4 suppressed flowering by regulating CO and FT expressions.