Department of Plant Developmental Biology
Plants spend their life in one position, and thrive in locations where they are exposed to a wide variety of environmental conditions. This versatility is possible because they continuously monitor and respond to environmental stimuli such as light, temperature and the availability of nutrients. Such responses alter the growth habit and form of the plant adapting it to its particular environment. We study the molecular mechanisms that underlie this plasticity and that enable plants to alter their developmental programmes in response to environmental cues. Our studies employ molecular-genetic, genomic, biochemical and imaging-based approaches in the model species Arabidopsis thaliana. Increasingly, we are also interested in comparative approaches that determine how the mechanisms discovered in A. thaliana differ in other plant species that exhibit distinct environmental or developmental responses.
Our objective is to understand the molecular mechanisms that underlie environmental plasticity in key developmental processes. A striking example is the initiation of reproductive development through the induction of floral development. Many plants flower when exposed to appropriate environmental cues, thereby generating seasonal patterns in reproduction. This plasticity to environmental cues is important in ensuring that plants initiate reproduction at the appropriate time to produce the optimal number of progeny, thereby enabling adaptation to particular locations in natural populations and maximizing yield of crop plants in agricultural contexts. The function of key regulatory proteins and how they are controlled by environmental signals to induce flowering at particular times of the year is studied in the Department. A major interest has been to provide a detailed description of the biochemical mechanisms used in A. thaliana to measure day length, and to explain how this information is used to initiate inflorescence and floral development. This led us to a wider set of biological problems related to systemic signalling between plant organs, integration of signalling pathways triggered by different environmental cues, integration of environmental signalling with endogenous developmental programmes and fundamental issues of gene regulation related to chromatin modification.
In addition to the plasticity of environmental responses observed in individual plants, the extent and variety of these responses evolve rapidly among species and are closely related to life history. A dramatic example is the divergence of annual and perennial life history. Ephemeral annuals such as A. thaliana live for a few months and flower only once during their life cycle, whereas closely related perennials live for many years and flower each year. These distinct life histories involve many genetic differences but arise rapidly in evolution so that sister species can be annual or perennial. We study the divergence of these processes during evolution using perennial Arabis alpina, a relative of A. thaliana, and closely related Arabis annual species. We focus on divergence of reproductive development and senescence patterns. In addition, we compare the mechanisms uncovered in these members of the Brassicaceae family with those found in agriculturally important cereals by studying flowering responses of barley and its perennial relatives.