title: Effect of transporters on the secretion of phytochemicals by the roots of Arabidopsis thaliana.
abstract: Root exudation, the process by which plants secrete compounds into the soil, is becoming accepted as a communicative process that determines organismal interactions in the rhizosphere. However, the mechanistic processes involved in the root exudation of phytochemicals have not been elucidated; traditionally, exudation has been regarded as a passive process. There is evidence that transporters in plants (and other organisms) have been involved in the movement of chemicals across different membranes. Here, we describe the involvement of different transporters in root exudation of phytochemicals by employing a pharmacological approach. We used a range of concentrations of several compounds known to inhibit different transporters, including potassium cyanide, orthovanadate, quinidine, glibenclamide, nifedipine and verapamil, to examine the effects of transporter inhibition on root exudation profiles in Arabidopsis. Generally, the exudation profile of phenolic compounds in 18-day-old plants shows more than 15 major phytochemicals. In contrast, the inhibitors listed above caused differences in the secretion of specific compounds. For instance, nifedipine and verapamil completely inhibited the exudation of the phytochemicals with molecular masses of 142 and 294, respectively. These results highlight that root exudation of phytochemicals is an active process controlled at the biochemical level and that different transporters may be involved in this root-specific mechanism.
authors.affiliation: Unidad de Bioquímica y Biología Molecular de Plantas, Centro de Investigación Científica de Yucatán, Calle 43 No 130, Col Chuburná de Hidalgo, Merida, Yucatan, Mexico. vmloyola@cicy.mx
authors.forename: Victor M
authors.initials: VM
authors.lastname: Loyola-Vargas
authors.forename: Corey D
authors.initials: CD
authors.lastname: Broeckling
authors.forename: Dayakar
authors.initials: D
authors.lastname: Badri
authors.forename: Jorge M
authors.initials: JM
authors.lastname: Vivanco
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D017360:Arabidopsis / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D001693:Biological Transport, Active; D002121:Calcium Channel Blockers / Q000494:pharmacology; D018517:Plant Roots / Q000378:metabolism*; D026902:Potassium Channel Blockers / Q000494:pharmacology
chemical_list: D018528:ATP-Binding Cassette Transporters; D002121:Calcium Channel Blockers; D026902:Potassium Channel Blockers