Background

Paraquat (PQ), a non-selective broad-spectrum herbicide, has been widely used in weed control. It mainly acts on plant green tissue and is relatively safe for soil microorganisms and plant roots (Huang et al., 2019). It competes for electrons from the photosynthesis system I (PS I) and reacts with oxygen, producing a large quantity of reactive oxygen species (ROS) that destroy the photosynthesis system and ultimately kill plants (Apel and Hirt, 2004). However, with the heavy use of PQ, resistant weeds have emerged (Hawkes, 2014). Through extensive studies of PQ-resistant weeds and Arabidopsis, several molecular mechanisms of PQ resistance have been unraveled. These include disrupted PQ transport that blocks it from reaching its target, PQ sequestration into the vacuole and apoplast, enhanced ability to scavenge ROS, and PQ detoxification (Chen et al., 2009; Fujita et al., 2012; Xi et al., 2012; Li et al., 2013; Luo et al., 2016; Lv et al., 2021; Xia et al., 2021; Huang et al., 2022; Nazish et al., 2022).

To study the function of the MATE transporter DTX6, we designed an experiment using ¹⁴C-paraquat and Arabidopsis protoplasts to confirm its PQ-exporting activity from cytosol to apoplast, which assisted us in revealing the PQ resistance mechanism via sequestration.