www.checkbiotech.org ; www.raupp.info ; www.czu.cz

Roots are crucial for the development of strong, healthy crops. But until
recently, exactly which genes are involved in the development of roots was
still a mystery, October 2005.

Scientists from the Flanders Interuniversity Institute for Biotechnology
(VIB) connected to Ghent University have now analyzed a complete plant
genome in order to identify the genes that are essential for the formation
of capillary roots. For the first time, they are unraveling the genetic
basis for the branching of the root system ? the key to a plant's further
growth and development.

The mystery of capillary root formation

Root systems absorb nutrients and anchor plants in the soil ? two crucial
functions for a plant's growth and further development. The formation of
capillary roots is vital to the root system and determines how much water
and minerals a plant can absorb. As early as 1937, scientists knew that it
takes only 4 months for a single rye plant to produce some 13 million
individual roots! But up to now, the genetic basis of this complex process
has remained unexplained.

The production of new roots is a complex combination of cell division,
growth and differentiation. A specialized layer of cells in the root ? the
pericycle cells ? must be activated to start dividing again. Therefore, it
is also crucial that the cell cycle ? the process that directs cell division
? be under optimal control. Although the precise factors that underlie these
processes and how they work together are virtually unknown, it has been
quite clear that an enormous number of factors are involved.

Tom Beeckman and his team in the VIB Department of Plant Systems Biology
took on the challenge of identifying all the genes that are involved in the
process of capillary root formation. They used a simple model plant for this
study: the Mouse-ear Cress or Arabidopsis thaliana.

Large-scale research identifies genes involved in capillary root formation

First of all, the researchers developed a special method ? the Lateral
Root-Inducible System (LRIS) ? with which they are able to have capillary
roots grow in a controlled manner. They studied all the genes that are
connected with the formation of capillary roots and compared them with the
complete genome of a plant that is unable to form capillary roots. By
analyzing these large data sets in detail, the Ghent team discovered which
genes are crucial for the formation of new capillary roots. For this part of
the project, they used micro-array technology, with which thousands of
samples can be studied simultaneously.

The development of capillary roots is important for sustainable agriculture

Capillary root formation is controlled by both internal and external
signals. This ensures that the root system adapts itself to changes in the
soil ? a very heterogeneous and changeable environment. From the
agricultural point of view, the branching of the root is essential because
roots are responsible for helping plants adapt to adverse environmental
conditions. A better understanding of capillary root formation will enable
the cultivation of crops that absorb water and minerals more efficiently. An
important step toward a more environment-friendly, sustainable agriculture
in a world whose population is growing while the land available for
agriculture is diminishing.

[www.vib.be]

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