Phylotranscriptomic analysis of post-embryonic plant development

The developmental  hourglass represents one of the classic concepts in developmental  biology. It describes the morphological progression of embryos from  related animal species from conception to birth. While early-stage  embryos appear different, they surprisingly converge on a similar form  towards mid-embryogenesis, only to diverge again in late embryogenesis.  Although convincing molecular support has recently been generated for  this historically anatomic phenomenon, the function of the developmental  hourglass and how it is regulated still remains an enigma. We could  recently show that a molecular hourglass exists not only in the animal  kingdom, but that a similar transcriptional pattern convergently evolved  also in the plant kingdom. Together, this suggests the existence of a  common, but independently evolved, logic that controls embryogenesis  across kingdoms. However, in contrast to animals, plant development  takes place not primarily during embryogenesis, but rather during  post-embryonic life. Based on this observation, we hypothesize that not  only embryogenesis but also post-embryonic developmental processes may  be regulated in an evolutionary conserved manner. We plan to test this  hypothesis for different developmental processes in the next few years,  and within this proposal we plan to test it for flower initiation, one  of the most essential post-embryonic developmental processes in  angiosperms. We plan to test this hypothesis by generating  high-resolution transcriptome times series of ten different stages  during flower initiation in three related species from the Brassicaceae  genus including the model plant Arabidopsis thaliana.