Sequence Comparison And Function Analysis Of Relevant Genes On The Development Of Petunia Double Flower

The study on floral development has been the research hotpot in the field of plant for a long time. Over the last twenty years, from the ABC model to the ABCDE model, the theory is still being developing. While double flower, as a kind of plant material with high artistic and economic value, is the goal of breeding. As for its molecular mechanism,people did a lot of work based on the ABC(DE) model using forward genetic approach and reverse genetic approach, the research results mostly focus on B-class gene and C-class gene. As one of the model plants for studying floral development, the double flowers of petunia show petaloid stamen and number increase of stamen.It has been reported that when the two C-class genes, PMADS3 and FBP6, lose their function, the stamens advert to petals and the floral determinacy is lost, but the increase of floral organs’ number is not observed. So we purpose that in the formation process of the double flower, there must be some other genes involved. Our laboratory did suppress subtractive hybridization, microarray and RT-PCR with the single and double flower petunia which are planted in our school to analysis the gene expression difference between the single flower petunia and double flower petunia. In the end, we found 6 genes, PMADS3(gi|313112),FBP6(gi|374086023),PMADS12(gi|34452082),FBP20(gi|13384053),sc PD4(gi|227581095),ssh PD1(gi|20492). the experiment is to analysis why they expressed differently between the petunia near-isogenic line and the function they have.And the consequences are as follows.1. The promoters of the above genes and some other part of PMADS3 and FBP6 were cloned with the DNA of single petunia and double petunia as template respectively,mainly including the promoters of PMADS3,FBP6,PMADS12,FBP20,sc PD4,ssh PD1,the full length of PMADS3 and the second intron of FBP6. Aligning the sequence between single flower and double flower, the results show that there is no difference between the sequence, especially in the key element.2. Based on the different expression level between the petunia near-isogenic line,RNA interference vectors were constructed for petunia transformation, including thegenes PMADS12, FBP20, sc PD4, ssh PD1. And the over expression vector of PMADS12 had been constructed by a senior student. The above five vector were transformed into petunia line W115. We attained transgenic plants: PMADS12-RNAi,23 plants;FBP20-RNAi, 18 plants; sc PD4-RNAi, 20plants; ssh PD1-RNAi, 28 plants; PMADS12-ov,12 plants. We observed the phenotype of the transgenic plants, and found that a filament was fused with petal in a flower of a PMADS12-over-expression transgenic plant. there is no more apparent difference between the transgenic plants and wild plants. More analyses are needed.According to the above results, we thought that the different expression level between single petunia and double petunia was not caused by the promoters or the regulatory elements of above genes. Especially the sequence of PMADS3 and FBP6 are not changed, which have been proved to be involved in the formation of double flower.As for the transgenic plants, more analyses is needed.