Petal Fusion in Petunias

Plants morphological diversity is governed by variation in size, number, shape, identity, and fusion of parts. A critical component in understanding the evolution of morphological diversity is determining what genes and gene networks underlie each of these traits. As one of these key components of floral morphology, the fusion of parts is an essential trait to understand and analyze. However, the genes and gene networks that determine whether organs are fused or free are not currently well understood. To gain more insight into the genetic basis of organ fusion, the Preston lab is using partially fused petunia petals as a model. In a comparative transcriptome experiment, several genes in Petunia were identified to be differentially expressed between the distal free petals lobes and the proximal fused petal tube, making them good candidates for further study. Two of these genes belong to the TCP family of transcription factors, known to have diverse functions in determining petal shape, corolla symmetry, and overall petal growth. We are in the process of functionally characterizing the impact of these candidate TCP genes on petunia petal morphogenesis using Virus-Induced Gene Silencing (VIGS)