Control of reproduction by seasonal cues in annual and perennial plants

Reproduction is tightly controlled in all organisms. In plants, the induction of flowering is the first step in reproduction and is controlled by seasonal cues such as day length and winter temperatures. These processes are integrated into the life cycles of different plant species, such as annuals that reproduce only once in their life time and perennials that live for many years and reproduce each year. We use the annual model Arabidopsis thaliana to decipher regulatory networks controlling these responses and exploit relative species, particularly perennial Arabis alpina, to determine how these networks change during evolution to confer ecologically significant differences in phenotype. We have shown how circadian-clock regulation of transcription of specific regulatory genes and photoreceptor signalling combine to promote flowering in response to long summer days. This process activates expression in the leaf of a protein that moves systemically to the shoot meristem and reprogrammes transcription leading to flower development. More recently, we showed how a network of microRNAs and transcription factors act in the shoot apex to control the age at which the plant becomes sensitive to environmental cues. The activity of this network differs between annuals and perennials, effectively delaying flowering of perennials. The talk will describe our recent progress in understanding regulatory processes that control the transition to flowering and how these diverge during evolution.