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FP7

SHOOT APICAL MERISTEM Result In Brief

Project ID: 249270
Funded under: FP7-PEOPLE
Country: Israel

The fate of a cell in a plant shoot

What determines the phenotype of a developing cell? An EU-funded initiative has found out how genes and proteins steer plant root cells to their final identity.
The fate of a cell in a plant shoot
As an overall recipe, cell fates are established by either expressing or turning off the genes responsible for the development of a cell. Transcription factors (TFs) orchestrate this process as they bind to specific DNA sequences to activate or repress transcription.

In plant shoots, growth is accompanied by precise differentiation into tissues such as stem tissues, leaves, flowers and vascular elements. The shoot apical meristem (SAM) by definition contains undifferentiated cells that are organised into multiple functionally distinct zones. The SAM sustains plant growth by producing new organs from a pool of self-renewing pluripotent stem cells. These can develop into any type of cell, which in turn gives rise to specific tissues and organs.

The studies of the SHOOT APICAL MERISTEM project revolved around two genes for stem cell specification: WUCHEL (WUS) and SHOOTMERISTEMLESS (STM). WUS is only expressed in a small hub of cells in the centre of the meristem known as the organising centre. STM is expressed in most cells in the meristem and antagonises cell differentiation so many daughter cells can proliferate before developing into a certain organ.

Team members constructed transgenic plants carrying tagged WUS and STM to identify their respective direct target genes. They found that with no added hormones, activated WUS gave rise to new meristems but plant hormones, high auxin and low cytokine, blocked new meristem generation.

Inducing increased levels of WUS and STM expsion in Arabidopsis mutants, the researchers found that the leaf arrangement, phyllotaxy, changed. There was a gradual shift from spiral to whorled leaf pattern. This work involves the regulator of WUS expression, ERECTA. The research results feature in the journal Development.

SHOOT APICAL MERISTEM are waiting for the results of chromatin immunoprecipitation (ChIP) and massively parallel sequencing, ChIP-Seq, to accurately survey interactions between protein, DNA and RNA. The researchers will then be able to construct a model for the genetic network regulating cell specification at the shoot apical meristem.

The SHOOT APICAL MERISTEM project has completed a highly important research initiative. With the current global food crisis, for example, a firm knowledge platform of the molecular control of plant development is essential to maximise crop yield.

Related information

Keywords

Cell differentiation, transcription factor, WUS, STM, apical meristem, phyllotaxy
Record Number: 150729 / Last updated on: 2014-11-20
Domain: Biology, Medicine
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