FUNCTION OF ROOT BORDER CELLS IN PLANT HEALTH - PIONEERS IN THE RHIZOSPHERE

Plants dedicate a large amount of energy to the regulated production o f living cells programmed to separate from roots into the external env ironment. This unusual process may be worth the cost because it enable s the plant to dictate which species will share its ecological niche. For example, border cells can rapidly attract and stimulate growth in some microorganisms and repel and inhibit the growth of others. Such s pecificity may provide a way to control the dynamics of adjacent micro bial populations in the soil to foster beneficial associations and inh ibit pathogenic invasion. Plant genes controlling the delivery of bord er cells and the expression of their unique properties provide tools t o genetically engineer plants with altered border cell quality and qua ntity. Such variants are being used to test the hypothesis that the fu nction of border cells is to protect plant health by controlling the e cology of the root system.