During plant development new organ and tissue development occurs throughout the plant life cycle largely through the action of meristems. The entire plant shoot system is ultimately derived from the primary shoot apical meristem, which is laid down during embryogenesis. However, post-embryonically, secondary shoot apical meristems which arise in the axils of leaves leading to lateral branches; and cambium, which arises in the developing vasculature and gives rise to phloem and xylem, also play a central role in the development of the shoot system. The activity of these meristems can be regulated environmentally and developmentally leading to a great deal of variability in activity throughout the year and life cycle of the plant. Of great interest to us is the cycling of these meristems between dormancy, a paradoxically active state, and activity, the transitions between being of fundamental importance in agriculture, horticulture and forestry.

In order to understand further the regulation of this transition between dormancy and activity we are undertaking a number of different approaches. Initially each laboratory in this consortium is using a transcriptomics-based approach to identify transcripts that are differentially regulated in seed dormancy versus activity (Carrera and Holdsworth), bud dormancy versus activity (Ward and Leyser) and cambial activity (Dubos and Campbell). The data thus produced will be analysed to identify transcripts common to one or more of these developmental states. A number of genes will be identified that characterise the dormant or active state and these will be arrayed on an oligo array. Such an array has already been produced for transcripts that are differentially expressed in dormant versus active buds. We are also looking for common components through the study of previously identified Arabidopsis mutants that display defects in either seed dormancy, shoot branching or cambial activity to see if they also have defects in other dormant meristems.

Semi-Q RT-PCR markers

Promoter GUS markers