Evolutionary study of peta-like organ in Angiosperms

点击翻译按钮获取中文摘要

The morphogenesis model of the flower, which is called the ABC model, had been advocated and, is widely accepted as the result of molecular genetic analyzes of mutant flowers. The ABC model is also applicable to the flower of rice, which has a different structure from those of Arabidopsis, and is seems to be fit in most angiosperms.The flower of Houttuynia cordata consists of 3 stamens and 3 carpels, and have no perianth. But, they have a white petal-like organ at the base of the inflorescence ,which is called the involucral bract, because they are attached to the lowest position of inflorescence. In this study, we focused on mechanism of petal-like organ formation, especially whether the ABC model having participated in this involucral bract formation, or it had acquired with different evolution process. Thus, the MADS-box genes had been cloned and characterized in H. cordata. Then, expression of each gene was inspected by quantity RT-PCR and in situ hybridization. As a result, expression of the genes belonging to the API group, the PI group, the AP3 group and the SEP group had been observed in the involucral bract of the H. cordata. As for combination of these gene expressions, it has become clear to be necessary sufficient ones to determination of the organ identity of the petals in Arabidopsis thaliana. This result suggests the possibility that the petal-like bract of H. cordata has similar detemination mechanism to the petal of Arabidopsis.