异源表达番茄蔗糖磷酸合成酶基因SlSPS促进拟南芥株型增大研究

The promotion effect of ectopic expression of tomato SlSPS gene(sucrose phosphate synthase)on the enlargement of plant type in Arabidopsis thaliana

为了探究番茄SlSPS基因的功能,通过克隆番茄中SlSPS基因,构建过表达载体并在拟南芥中进行遗传转化,对获得的独立转化株系的蔗糖、可溶性糖含量,蔗糖磷酸合成酶活性,株型,花蕾、果荚和种子大小等进行鉴定。发现与野生型拟南芥幼苗相比,其SlSPS基因高表达,同时蔗糖磷酸合成酶活性、蔗糖和可溶性糖含量显著提高。此外,过表达SlSPS转基因植株的株型发生改变,幼苗增大,根长显著变长12.15%,叶片增大;成苗莲座叶变大,株高升高了24.69%;黑暗培养的幼苗下胚轴显著伸长17.09%;并且其花蕾增大,果荚长度显著提高了25.17%,种子大小也大于野生型。在拟南芥中异源过表达SlSPS基因提高了蔗糖磷酸合成酶的活性,和蔗糖、可溶性糖含量,推测可能提高了能量的累积,从而导致营养生长和生殖生长的器官的大小都得到提升,使得株型变大。本研究揭示了番茄SlSPS基因促进生长发育的功能,为该基因功能的深入挖掘和番茄品质遗传改良提供了理论依据。

Tomato is a widely cultivated vegetable crop and model plant in the world.Sucrose phosphate synthase(SPS)is the key rate-limiting enzyme for sucrose synthesis in plants.To investigate the function of SlSPS gene in tomato,SlSPS gene was ectopic expressed in Arabidopsis thaliana,and the sucrose and soluble sugar levels,sucrose phosphate synthase activity,plant type,size of flower bud,fruit pod and seed of the independent transgenic lines were identified.The expression level of SlSPS gene and sucrose phosphate synthase activity were significantly increased.The contents of sucrose and soluble sugar were also promoted in transgenic lines.In addition,the transgenic plants showed increased seedling size,root length(by 12.15%)and leaf size.The hypocotyl elongated by 17.09%significantly in dark culture.The seedling height and pod length increased significantly by 24.69%and 25.17%respectively,and the rosette leaf became larger.The flower buds were enlarged and the seed size was larger than that of wild-type Arabidopsis seeds.Overexpression of SlSPS gene in Arabidopsis thaliana can increase the activity of sucrose phosphate synthase and the content of sucrose and soluble sugar.It is speculated that overexpression of SlSPS gene can increase the inner energy,therefore increase the size of vegetative and reproductive growth organs and make the plant type larger.This study reveals the development and growth promotion functions of SlSPS gene and provides a theoretical basis for further exploration of the function of SlSPS gene and genetic improvement of tomato quality.