The Construction Of Anthocyanin Vectors As Visual Markers And Preliminary Study On Its Expression In Maize

Currently, the selectable marker genes used in most plant transgenic systems are herbicide resistant genes, antibiotic genes, and other toxic genes to cell metabolism. The food and environmental safety concerns on those genes have hindered the extensive use of the transgenic crops in commercial production. In this study, anthocyanin regulatory factor C1/Bperu genes are constructed respectively with a maize embryo specific promoter G1b1 and a constitutive promoter CaMV35S into plant transformation. The recombinant expression vectors were then introduced into maize embryos by particle bombardment and microscopic observation confirmed that these two vectors were actively expressed in maize immature embryo cells. The use of anthocyanin genes as marker genes not only reduces the safety concerns from the public over GMO substantially, but also provides a visual indicator for the selection of transgenic plants, which will greatly simplify the screening procedures, improve the efficiency and reduce the costs. The utilization of this type of selection markers will have great implications for the research community in the area and the application of transgenic crops in the industry. In addition, as naturally existing water-soluble pigments, anthocyanins have strong antioxidant and free radical scavenging capacity for humans and animals, which play important roles in the prevention of aging, cardiovascular disease, cancer, and so on. Anthocyanin genes as safety marker genes have dual functions, namely the role of both the marker gene, and the target gene. Therefore, anthocyanins as marker have broad application prospects.The ultrasonic-assisted pollen mediated method is the first case of a non-tissue culture transgenic method with completely independent intellectual property owned by Chinese researchers and widespread application prospect, which is applicable to flowering plants. In this method, pollen as vector mediate exogenous gene transformation, which avoids problems that occur with traditional tissue culture transformation, for example, genotype-dependency of success tissue regeneration difficulties, premature death of seedling offspring infertility, somatic mutations transformation chimeras, high costs and low transformation rate.This study constructed vectors pG1b1CB and p35SCB using anthocyanin as marker gene and the constructs were used in the pollen mediated maize transformation. Anthocyanin was expressed in maize embryos and transformed progenies. This led to direct colour expression and preliminary screen was performed by the selection of purple or red embryo or seeds, and untransformed embryos remain in white colour.The combination of anthocyanin marker gene and pollen mediated transformation will undoubtedly simplify the transformation procedure in plants which overcomes all the problems present in the tissue culture-based methods. This will also substantially improve and accelarate the screening process of the transformation.