The genetic analysis of cell fate switch in Arabidopsis

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

Abstract

Plants are sessile organisms that rapidly adapt their growth and metabolism to environmental changes by maintaining a high degree of cellular and developmental plasticity. The striking regenerative capacity of plants relies on the ability of many plant cell types to retain their totipotency, dedifferentiate and switch fate when external stimuli change. However, development and growth occur in an orderly manner indicating that there are mechanisms maintaining cell fate as well as promoting fate changes. The root epidermis of Arabidopsis is an excellent model to identify such mechanisms because: 1) it is composed of only two cell types, non-hair and hair cells that are specified in response to external stimuli i.e. positional information; 2) alternative chromatin states at the GL2 locus, which controls non-hair cell fate, are associated with the two-epidermal cell types and can be rapidly reorganised when cells switch fate in response to new positional cues. To identify the mechanisms controlling the maintenance and reprogramming of cell fate we will isolate chromatin mutants that are unable to correctly pattern the root epidermis throughout development and/or are unable to change identity when cells become exposed to new positional cues. To characterise the cascade of events leading to fate changes we will set up a genetic screen to identify mutants where epidermal cells are unable to switch fate. The outcomes of this project are expected to provide insights into how plant cells retain their totipotency and may offer new perspective on cellular dedifferentiation in animals.

Publications

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Description It is intriguing why some but not all organisms are able to regenerate missing body parts. Plants are remarkable because they can form new organs from old ones following changes in environmental conditions, wounding or severing. This capacity is important for plant survival in natural conditions and for horticultural propagation. However, the genetic and molecular mechanisms underlying such capacity are largely unknown and the aim of the grant was to identify the genetic basis of plant cell ability to change their identity and thus become reprogrammed.

The work undertaken has provided important insights into the role of cell division in cell identity acquisition. These are processes that occur during reprogramming and are central to the development of new tissues and organs but how they intersect still remains unclear. Thus, new, exciting results and ideas have emerged to be dissected in future research projects.

Since the work has been based on the setting up of a genetic screen that has led to the identification of new mutants, the work has also provided novel and interesting resources to further dissect and advance our genetic understanding of plant's ability to respond rapidly to external stimuli and acquire new identities.

The grant was largely supported by a Royal Society University Research Fellowship that has given me the unique opportunity to develop my independent research in a institute like the John Innes Centre, which is at the forefront of plant science and has a wide range of scientists undertaking top quality research.
Exploitation Route The work has an immediate impact on the scientific community, particularly on those research groups working on development, cell cycle and cytoskeleton. However, the understanding of the mechanisms integrating cell proliferation with cell identity acquisition during reprogramming and development provide new basic knowledge that will enable to manipulate precisely the plant traits we want, like for example, the length of roots or the amount of biomass, and minimise or abolish morphological changes.

To cope with an increasing demand for food and biofuels in rapidly changing environmental conditions across a global scale, we could increase plant growth and cell mass, but it is important we do so without affecting patterning and architecture since this could have a negative impact on the ecosystem by hindering plant interactions with other organisms, like soil microorganisms or pollinators. So the acquisition of the precise understanding of how cell proliferation and cell identity acquisition are integrated will lead to new insights on how to increase growth and cell mass without affecting patterning and architecture and also on how to improve horticultural propagation and plant regeneration.
Sectors Agriculture, Food and Drink,Environment,Manufacturing, including Industrial Biotechology

 
Description The results have been disseminated to the scientific community. The teaching to undergraduate and graduate students has been important in introducing young individuals to the creativity, but also to the rigorousness, of the scientific process and hopefully in inspiring new ideas and careers that will make an impact in the wider community.
First Year Of Impact 2011