The floral transition and adaptation to a changing environment: From model species to cereal crops

Over the course of their lives, animals and plants are exposed to environmental fluctuations associated with seasonal changes. In contrast to animals, postembryonic growth of many plants is highly plastic (meaning changeable). Due to their sessile nature, plants have evolved strategies to modulate the development of their organs (roots, shoots, leaves, flowers, fruits, seeds) in response to changes in external conditions. In particular, the development of reproductive organs must occur when conditions are favorable to ensure the success of the next generation. The switch from vegetative to reproductive development depends on many factors, both intrinsic (internal cues such as plant age and physiological state) and extrinsic (external cues such as hours of sunlight and climate). For example, gradual increases in daylength and temperature (e.g., winter to spring) provide environmental cues for plants growing in non-equatorial regions to coordinate the growth of vegetative and reproductive organs and produce seeds under optimal conditions. As plants move to new geographic locations (for example due to human interventions), they must retune their timing of reproduction; environmental stress can further affect flowering time. Seed production requires the plant to properly enter the reproductive phase, which in flowering plants is preceded by the floral transition. As much of the human diet is derived from seeds, understanding the molecular basis of flowering time is extremely important for both basic research and agronomic applications. This lesson examines the gene regulatory networks underpinning the floral transition, first looking at the model plant Arabidopsis thaliana and then at important cereal crops. Next, it explores how plants have adapted to different regions and how the changing climate might affect flowering and thus food security