The herbicide bensulfuron‐methyl inhibits rice seedling development by blocking calcium ion flux in the OsCNGC12 channel

Abstract

SUMMARYBensulfuron‐methyl (BSM) is a widely used herbicide in rice cultivation, but the mechanisms underlying its efficient uptake in rice are poorly understood. In this study, a yeast library expressing 1385 rice transporters was employed to screen proteins sensitive to BSM. As a result, a cyclic nucleotide‐gated channel (CNGC) protein, OsCNGC12, was identified. By inactivating the OsCNGC12 function via gene editing, we developed BSM‐tolerant rice lines. Our results showed that the OsCNGC12 mutant rice not only reduced BSM uptake but also promoted Ca2+ influx in the roots, leading to enhanced non‐target‐site tolerance to BSM. OsCNGC12 is localized in the plasma membrane and is abundantly expressed in the root caps, root vascular bundles, stems, and leaves, indicating its vital role in the distribution of BSM in rice. The indispensability of His‐236, Gln‐240, and Arg‐268 in BSM perception in yeast was demonstrated through targeted mutagenesis of OsCNGC12. Furthermore, we developed a BSM seed coating agent for OsCNGC12 mutant rice, providing a simplified and cost‐effective means of weed control in direct‐seeded rice. Inclusion, this study showed that disruption of OsCNGC12 confers non‐target‐site tolerance to BSM in rice and has the potential for developing BSM‐resistant rice varieties.