Cellular and regulatory basis of the early stages of stem development

Lead Research Organisation: John Innes Centre
Department Name: Contracts Office

Abstract

The initiation and control of stem development are among the least understood aspects of plant development, in spite of their importance in crop breeding. Stem development is initiated and in large part controlled within a region of the shoot meristem called the rib meristem (RM). In this proposal, we aim to understand the cellular basis of early stem development and how this cell behaviour is controlled by regulatory genes that function in the RM. We will use Arabidopsis as the model, but focus on regulatory pathways that are widely conserved and also control stem development in monocotyledons.
We aim to answer the following questions:
1.What cell division and growth patterns establish the girth of the stem and the size of the population of cells that eventually elongate to cause stem extension? We will use 3D, quantitative imaging and cell tracking to reveal the cell division and growth patterns in early wild-type stem development.
2.What changes in cell behaviour translate the activity of regulatory genes into macroscopic effects on stem growth? We will measure the effect of two major regulatory pathways (GA, BP /ATH1/RPL) on cell division and growth in the RM.
3.Do the RM regulators signal across tissues to co-ordinate cell proliferation and differentiation? We will use genetic mosaics to discriminate between cell autonomous functions and signalling roles of the RM regulators above.
4.Do the two RM regulatory pathways above converge on a common set of downstream targets and cellular processes, or do they affect stem growth though separate processes? We will use comparative transcriptome analysis to reveal the gene activities underlying the cell behaviour and signalling events analysed above.
Answering these questions will not only reveal the cellular and regulatory basis for how the plant stem is originated, but will also provide knowledge that can be applied in breeding for changes in plant architecture.

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