Genetic Regulatory Mechanisms Underlying Developmental Shifts in Plant Evolution

The origin and evolution of land plants is accompanied by major macro-evolutionary changes and profound shifts in their developmental transitions. While the gametophytic generation dominates in the mosses it was continuously reduced during the evolution of seed plants, with the sporophyte becoming the dominant phase of the life cycle. Concomitantly, cell types diversified, stem cell niches became polarized in the diploid axis and leaves achieved an extreme morphological variation. While originally heavily dependent on water for gamete transfer, in later phases of plant evolution, male gametes or gametophytes are dispersed by wind and later by animals. Additionally, the development of the female gametophyte was internalized and sperm motility was lost requiring a sperm delivery system reaching deep into the maternal tissues. Moreover, in seed plants the embryos are dispersed away protected within the seed, which retains a nutritional start-up package for the next generation. In flowering plants, both gamete-attracting and seed-dispersal mechanisms have diversified. Flowers have unlimited displays for pollination, mostly due to perianth presentation with elaborated coloration and symmetry. In addition, the carpel surrounds the ovules requiring fertilization to occur internally and, to reduce energy waste into improperly developing seeds, the endosperm develops with the embryo after double fertilization. Finally, as the carpels mature into fruits they showcase a wide array of forms that guarantee optimal seed dispersal.

What genes regulate each of these processes and how the genetic modules are specified over evolutionary time to control these transitions are key questions at the core of plant developmental research studies. Here, we propose a Research Topic to bring together the latest advances in the plant evo-devo field. We will cover themes related to the developmental basis of major transitions in land plant reproduction as well as the underlying evolutionary changes on their genetic regulatory networks in a concerted and comprehensive way.
We will include contributions in themes such as:
- the gene regulatory networks driving developmental transitions in land plants
- conservation of gene functions over deep phylogenetic timescales
-origin, maintenance and regulatory mechanisms of stem cells during the alternations of gametophyte and sporophyte generations,
- the molecular mechanisms related to flowering, double fertilization and fruit development
- molecular basis of seed maturation and dormancy
- evolution of the genetic network regulating male-female gametophyte interaction