Paraquat is one of the most widely used nonselective herbicides and has elicited the emergence of para-quat-resistant weeds.However,the molecular mechanisms of paraquat resistance are not completely un-derstood.Here w...Paraquat is one of the most widely used nonselective herbicides and has elicited the emergence of para-quat-resistant weeds.However,the molecular mechanisms of paraquat resistance are not completely un-derstood.Here we report the Arabidopsis gain-of-function mutant pqt15-D with significantly enhanced resistance to paraquat and the corresponding gene PQT15,which encodes the Multidrug and Toxic Extru-sion(MATE)transporter DTX6.A point mutation at+932 bp in DTX6 causes a G311E amino acid substitution,enhancing the paraquat resistance ofpqt15-D,and overexpression of DTX6/PQT15 in the wild-type plants also results in strong paraquat resistance.Moreover,heterologous expression of DTX6 and DTX6-D in Es-cherichia coil significantly enhances bacterial resistance to paraquat.Importantly,overexpression of DTX6-D enables Arabidopsis plants to tolerate 4 mM paraquat,a near-commercial application level.DTX6/PQT15 is localized in the plasma membrane and endomembrane,and functions as a paraquat efflux transporter as demonstrated by paraquat efflux assays with isolated protoplasts and bacterial cells.Taken together,our results demonstrate that DTX6/PQT15 is an efflux transporter that confers paraquat resis-tance by exporting paraquat out of the cytosol.These findings reveal a molecular mechanism of paraquat resistance in higher plants and provide a promising candidate gene for engineering paraquat-resistant crops.展开更多
基金supported by grants from the National Natural Science Foundation of China(grant no.31770273).
文摘Paraquat is one of the most widely used nonselective herbicides and has elicited the emergence of para-quat-resistant weeds.However,the molecular mechanisms of paraquat resistance are not completely un-derstood.Here we report the Arabidopsis gain-of-function mutant pqt15-D with significantly enhanced resistance to paraquat and the corresponding gene PQT15,which encodes the Multidrug and Toxic Extru-sion(MATE)transporter DTX6.A point mutation at+932 bp in DTX6 causes a G311E amino acid substitution,enhancing the paraquat resistance ofpqt15-D,and overexpression of DTX6/PQT15 in the wild-type plants also results in strong paraquat resistance.Moreover,heterologous expression of DTX6 and DTX6-D in Es-cherichia coil significantly enhances bacterial resistance to paraquat.Importantly,overexpression of DTX6-D enables Arabidopsis plants to tolerate 4 mM paraquat,a near-commercial application level.DTX6/PQT15 is localized in the plasma membrane and endomembrane,and functions as a paraquat efflux transporter as demonstrated by paraquat efflux assays with isolated protoplasts and bacterial cells.Taken together,our results demonstrate that DTX6/PQT15 is an efflux transporter that confers paraquat resis-tance by exporting paraquat out of the cytosol.These findings reveal a molecular mechanism of paraquat resistance in higher plants and provide a promising candidate gene for engineering paraquat-resistant crops.
