Flowering Time

Plants control the time at which they flower in order to ensure they reproduce in favourable conditions. Plants respond to environmental cues, like day-length and temperature, that are reliable indicators of seasonal progression, and these responses are integrated with an endogenous program of development. So flowering is controlled by many different pathways that promote, repress or enable flowering in a quantitative manner. Precision in gene regulation underpins this quantitative response.

The control of flowering time is an important part of how plants adapt to their environment and a key trait incorporated in crop plant breeding programmes. Rapid changes in the flowering time of many British plant species has provided the best biological evidence of recent climate change and inter-species differences in this response is likely to impact the structure of plant communities and ecosystems.

Using Arabidopsis as a model, we are working in two main areas:

First, we are studying FPA, an RNA binding protein that promotes flowering in the so-called autonomous pathway. Arabidopsis mutants that lack FPA flower extremely late. FPA enables flowering by preventing the accumulation of mRNA encoding the floral repressor, FLC. We are interested in determining exactly how FPA achieves this and defining how its function relates to other components of the autonomous pathway.

Second, we have taken a genetic approach to identify novel genes controlling flowering time. FT is required for floral promotion in many different plant species. FT protein moves from leaves to the shoot apex to promote flowering and is therefore likely to be the principal component of the long sought after floral regulator, florigen. Arabidopsis mutants that lack FT activity flower late. We have conducted a suppressor screen to identify mutants that flower early in the absence of FT. In this way we aim to identify genes that either work downstream of FT or work in parallel to FT to promote flowering. Some of the mutants we have isolated flower early independent of day-length and ambient temperature.

We are collaborating with colleagues at SCRI to translate our fundamental knowledge of flowering to cereals, like barley, and perennials, like raspberry.