Abstract
CRES-T is an efficient and useful gene silencing system in which a chimeric repressor of specific transcription factor suppresses the expression of its target gene dominantly. A transgenic Torenia expressing the chimeric AGAMOUS repressor (1069-51) showed serrated petal margin comparable to that treated with cytokinin (Nishijima, 2004). 1069-51 also showed the irregular development of vascular bundle in petals as well as ectopic and intensive vascular tissue formation in pistils, although these phenotypes were not observed in cytokinin-treated wild-type (wt) plants. Cytokinin treatment on 1069-51 caused marginal white variegation, deeper serration on petal edges, and multiplication of vascular bundle in pistils. The backcross population (wt x 1069-51) only showed the multiplication of vascular bundle in pistils. These results suggest that the signaling pathway involved in the cytokinin-regulated petal development in 1069-51 is somewhat affected by the chimeric AGAMOUS repressor. We will discuss the relationship between the 1069-51 phenotype and AGAMOUS functions.
