The role of root border cells in plant defense

The survival of a plant depends upon the capacity of root tips to sense and move towards water and other nutrients in the soil. Perhaps because of the root tip's vital role in plant health, it is ensheathed by large populatio ns of detached somatic cells - root 'border' cells - which have the ability to engineer the chemical and physical properties of the external environme nt. Of particular significance, is the production by border cells of specif ic chemicals that can dramatically alter the behavior of populations of soi lborne microflora. Molecular approaches are being used to identify and mani pulate the expression of plant genes that control the production and the sp ecialized properties of border cells in transgenic plants. Such plants can be used to test the hypothesis that these unusual cells act as a phalanx of biological 'goalies', which neutralize dangers to newly generated root tis sue as the root tip makes its way through soil.