Efﬂux Transporters as a Novel Herbivore Countermechanism to Plant Chemical Defenses
Jennifer S. Sorensen1,2 & M. Denise Dearing1
1Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
2NPS Pharmaceuticals, Salt Lake City, UT 84108, USA
The recent discovery of efﬂux transporters in the gut has revolutionized our understanding of the absorption and bioavailability of pharmaceuticals and other xenobiotics in humans. Despite the celebrity of efﬂux transporters in the areas of pharmacology and medicine, their signiﬁcance is only beginning to be realized in the area of plant–herbivore interactions. This review integrates reports on the importance of gut efﬂux transporters to diet selection by herbivores. The diets of herbivores are laden with toxic plant secondary metabolites (PSMs) that until recently were thought to be processed almost exclusively by detoxiﬁcation enzymes in the liver. We describe how efﬂux transporters in the gut may play a critical role in regulating the absorption of PSMs in herbivores and dictating diet selection. Recent studies suggest that the role of efﬂux transporters in mediating diet selection in herbivores may be as critical as detoxiﬁcation enzymes. In addition to diet selection, gut efﬂux transporters have implications for other aspects of plant–animal interactions. They may be signiﬁcant components of the evolutionary arms race that inﬂuences chemical diversity in plants. Furthermore, in agricultural systems, gut efﬂux transporters may play an important role in the effectiveness of pesticides. This synthesis paper introduces a new direction in plant–herbivore interactions by providing a complementary mechanism, regulated absorption, to detoxiﬁcation that may deﬁne tolerance to PSMs by herbivores.
Herbivores .Plantsecondarymetabolites .Regulatedabsorption . P-glycoprotein .Mammals .Efﬂuxtransporters.Dietselection .Herbivoretolerance . Transporterproteins