Cloning Of C1-I-2K1 And R-2K1, Transcription Factor Genes From Maize, And Their Influence To The Color Of Transgenic Tobacoo Flowers

Anthocyanin is one kind of the flavonoid, and it is also an important plant secondary metabolite. It can not only affect the plant polymorphism(especially the color of the flowers), but also the metabolic process in plant (especially the process of reproduction).The genes encoding enzymes that are needed during the anthocyanin synthesis are conservative in many higher flowering plants, especially among plants that have near relative. It implies that the difference among the regulative genes may affect the color of the flowers.C1 and R are two kinds of transcription factors from maize. Cl is one of a MYB transcriptional factors, and R, belongs to bHLH family. They can interact with each other and have important functions during anthocyanin synthesis. Then, cl-I, an allele of cl, was also isolated from maize. It was thought to act as a transcriptional represser in the anthocyanin pathway.In our experiment, we cloned two genes from maize line "2K1 purple", namely cl-I-2Kl and r-2Kl, and the proteins they encode belong to MYB and bHLH proteins respectively. Three binary expression vectors were constructed, which harbored the cl-I-2Kl, r-2Kl, and d-l-2Kl-r-2Kl respectively, driven by the CaMV 35S promoter. Then, Agrofeac/erium-mediated transformation of iobacco(Nicotiana tabacum, W38) was carried out. Transformed tobacco lines were obtained through tissue culture and confirmed by PCR and southern blotting analysis.The results indicate the tobacco lines transformed with d-I-2Kl have white flowers and those transformed with r-2Kl and d-l-2Kl-r-2Kl don't have obvious changes, similar to that of the wild tobacco. So we can speculate that: first, d-I-2Kl can restrain the synthesis of the tobacco anthocyanin; second, the regulatory mechanism of the anthocyanin synthesis may be conservative among higher flowering plants; third, there are not obvious changes in the flowers of tobacco lines transformed with r-2Kl; fourth, R-2K1 protein can inhibit the effect of CI-I-2K1, with the cooperration of C1-I-2K1; fifth, it is a possible way to alter the color of the plant flower by transgene.