Pigmented maize seed via tissue-specific expression of anthocyanin pathway gene transcription factors

A visual marker genetically linked to a trait of interest would enable the unequivocal identification of transgenic seed containing the trait and ensure that genetically modified material could be easily differentiated from non-transgenic grain. Genes from maize that regulate the anthocyanin biosynthetic pathway, and are therefore responsible for directing the pattern of purple pigmentation, can be used to generate transgenic plants with unique, easily recognizable phenotypes. In the present study, a seed-specific maize globulin promoter was used to drive the expression of two transcription factor genes (Bp and C1) regulating the anthocyanin biosynthetic pathway in embryo and aleurone tissues resulting in maize seed with a distinct purple pigmentation. The following report describes the construction of expression vectors containing these two genes and an herbicide resistance selectable marker gene, the generation and characterization of transgenic cultures, the induction of pigmentation in somatic embryos, the regeneration of transgenic plants with pigmented seed and the co-segregation of integrated DNA with seed pigmentation and herbicide resistance. The co-segregation of seed pigmentation and herbicide resistance confirms the feasibility of using the expression of these genes in a 'molecular stack' for visual transgene identification.