Vacuolar Protein Sorting Genes Contribute to Paraquat Resistance in Eleusine indica

Abstract

This study investigates resistance mechanisms in a paraquat (PQ)-resistant Eleusine indica population. The resistant population exhibited 27.5-fold resistance to PQ. Although leaf absorption of 14C-PQ was similar to that in susceptible plants, translocation from treated leaves was significantly lower in resistant plants (3.6% vs 18.8%). Cellular fractionation showed reduced PQ accumulation in chloroplasts but increased levels in the cytosol/vacuole fraction. Following PQ treatment, photosynthetic parameters initially declined but later recovered in the resistant population, which also displayed higher glutathione peroxidase activity. RNA-seq analysis further revealed that two vacuolar transport-related genes, VPS26A and VPS32.2, were overexpressed in resistant plants regardless of PQ treatment. Importantly, transgenic rice seedlings overexpressing these genes exhibited resistance to the field rate of PQ. Together, these findings suggest that vacuolar protein sorting mechanisms, along with enhanced antioxidant activity, contribute to PQ resistance in E. indica.