Developing Streptocarpus as a model of meristem initiation
A.C. WILLOUGHBY, L. STRADER
Department of Biology, Duke University, 415 CHAPEL DRIVE, Durham, NC 27708, USA

The genus Streptocarpus in the Gesneriaceae has evolved unique meristem biology; the functions of the shoot apical meristem (SAM) have been shifted to the leaves. Streptocarpus leaves express genes normally restricted to SAMs, which I hypothesize provides these plants with the ease of regeneration from leaf tissue without applied hormones. As in vitro regeneration recalcitrance is a crucial bottleneck for plant biotechnology, I am developing these plants as a model system to unpack the mechanisms of meristem initiation. Streptocarpus plants lack a shoot apical meristem (SAM) from germination, and some species grow as a single indeterminant cotyledon, whereas others iteratively produce petiole-derived leaves. I am assembling Gesneriaceae genomes de novo to study the evolution of these growth habits, focusing on several Streptocarpus species as well as an independent lineage, Monophyllaea , to identify the shared genetic basis behind their flexible meristem program. I also am developing transformation and mutagenesis protocols to study the genes involved and how they impact plant regeneration.