Biosynthesis and Distribution of Phytoestrogens and Their Roles in Plant Defense,Signal Transduction,and Cell-to-Cell Signaling

Phytoestrogens are natural products from plants that function as estrogen agonists. Here we briefly review the biochemistry, distribution, and proposed roles of phytoestrogens in plants. A primary role appears to be in host-microbe interactions. For example, results from our laboratory suggest that genistein plays multiple roles in soybean defense, including the initiation of hypersensitive (apoptotic) cell death and the activation or potentiation of the defense competency of soybean cells. Recent results from our laboratory suggest that mammalian estrogens and estrogen agonists (including other phytoestrogens and fungal estrogen agonists) and certain specific peroxisome proliferators can also potentiate defense competency in soybean. These findings suggest that some overlap in nuclear receptor or other lipid/steroid signaling pathways may exist between plants and animals.