Transforming Brassica Juncea With Expression Vectors FLC-FLAG And SVP-HA

In higher plants, successful sexual reproduction and the evolution of species depends on flowering at the right time. Flowering time is a major life-history trait that contributes to fitness in plants, especially in crops which need to harvest vegetative organs. Thus, Extension of vegetative growth cycle by delaying the flowering time plays an important role in obtaining the higher crop yield.In China,mustard (Brassica juncea) is one of the main cruciferous crops, having extensive acreage, and "bolting" is important biological characteristics. Early flowering can severely reduce the yield and quality of mustard in its production. The fundamental way to solve this problem is to breed a late flowering type through delaying the flowering time of mustard.Flowering is the result of an important stage change in the life cycle of higher plants and the switch from vegetative to reproductive growth. Flowering is regulated by the impact of the environment, plant morphology and physiology, which were determined by target genes. Molecular biology studies have shown that the genes in regulation of flowering were divided into four categories:flowering time genes, floral meristem identity genes, flower organ identity genes and circadian clock genes. These genes are composed of a complex regulatory network, regulating flowering by four pathways, including photoperiod pathway in response to environmental signals, vernalization pathway in response to low temperature, gibberellin pathway in response to endogenous hormones, and autonomous pathway in response to self development. In the model plant Arabidopsis thaliana, overexpression of FLC (Flowering Locus C) and SVP (Short Vegetative Phase), the central regulatory factors, can repress the plant flowering.Based on a large number of study of the flowering genes, FLC and SVP were selected to further elucidate the interaction among various flowering genetic pathways that control the integration of flowering signals, and tried to find a way to delay the flowering.In this study, the complete plants of mustard (Brassica juncea Coss.) were obtained through tissue culture of its seedling stage hypocotyls, Agrobacterium-mediated, and finally confirmed by PCR.The results below showed: Germination medium, MS+NAAO.lmg/L+6-BAlmg/L; Seeding age,5d; Root initiation medium,1/2MS(3%sucrose,0.8%agar, pH5.8)+NAA0.1mg/L; Carbenicillin concentration:300mg/L; Pre-culture time,2d; Cocultivation time,3d; Agrobacterium infection, culture OD6000.5for10min; Under the concentration of hygromycin4mg/L, indicating that the differentiation into higher stage were completely inhibited. PCR analysis proved that FLC-FLAG and SVP-HA have been successfully transferred into the mustard.