Transformation and regeneration of Petunia

Abstract

Petunia has played a central role in transformation research since the earliest reports of plant transformation. It was a key model system when the first definitive accounts of Agrobacterium-mediated transformation and direct DNA transfer unequivocally established the transfer and expression of foreign genes in plants. Petunia subsequently played an important role in elucidating many of the characteristics of plant transformation, including unique sites of insertion, variable expression levels, and modified T-DNA structures among independently derived transformants. It was central in the demonstration of transient expression immediately following co-cultivation and transgene-induced silencing of gene expression, two phenomena currently of great importance in studies of gene function. One of the key reasons for the importance of Petunia in plant transformation research has been the selection for and/or identification of genotypes well suited to growth and regeneration in culture, for example, Petunia Mitchell, for which a simple transformation protocol is described. Agro-infiltration for transient gene expression and the development of intragenic vectors to effect gene transfer without the integration of "foreign" DNA represent recent advancements in Petunia transformation. Ease of transformation, coupled with other favorable biological characteristics, ensure that Petunia will remain a valuable model system for studies of gene function in plants.