The rhizosphere is a largely unexplored frontier for genetic engineeri
ng, Processes in the rhizosphere influence plant disease, plant nutrit
ion and root architecture by affecting the dynamics of microbial popul
ations and communities, There is interest in engineering plants to man
ipulate the rhizosphere for numerous reasons, Such plants might resist
soilborne pathogens more effectively, be better hosts to beneficial m
icroorganisms, remediate toxic waste, or attract communities of soil m
icroorganisms that enhance plant health. Central among the strategies
to engineer the rhizosphere is the effort to create a 'biased rhizosph
ere', which involves engineering plants to secrete nutrients that spec
ifically enhance the growth of desirable microorganisms.