Alternative agriculture, which expands the uses of plants well beyond food
and fiber, is beginning to change plant biology, Two plant-based biotechnol
ogies were recently developed that take advantage of the ability of plant r
oots to absorb or secrete various substances. They are (i) phytoextraction,
the use of plants to remove pollutants from the environment and (ii) rhizo
secretion, a subset of molecular farming, designed to produce and secrete v
aluable natural products and recombinant proteins from roots. Here we discu
ss recent advances in these technologies and assess their potential in soil
remediation, drug discovery, and molecular farming.