Researchers from the Weed Monitoring and Management Innovation Team at the Institute of Plant Protection, Chinese Academy of Agricultural Sciences (IPPCAAS), have published a paper in Plant Physiology titled “An ABCG-type transporter endows fomesafen resistance in Amaranthus retroflexus L.” The study reveals a novel mechanism by which the ABC transporter ArABCG5 confers herbicide resistance by mediating subcellular distribution of the herbicide.

Amaranthus retroflexus L. is a noxious weed in soybean fields, causing yield losses through competition with soybean. The protoporphyrinogen oxidase (PPO)-inhibiting herbicide fomesafen is registered for controlling A. retroflexus in soybean fields. However, prolonged and repeated use of fomesafen has led to the evolution of resistance in A. retroflexus, constraining stable soybean production. Understanding the resistance mechanism of A. retroflexus to fomesafen is therefore critical for sustainable weed management in soybean production.

In this study, the researchers identified a significantly upregulated ABC transporter gene, ArABCG5, in a fomesafen-resistant population of A. retroflexus collected from Heilongjiang Province. Overexpression of ArABCG5 in Arabidopsis conferred resistance to fomesafen. Knockdown of ArABCG5 using virusinduced gene silencing significantly reduced resistance levels in A. retroflexus. Subcellular localization analysis, structural modeling and molecular docking showed that the transporter is localized to the plasma membrane and is involved in transporting fomesafen to the extracellular space. This work provides a theoretical basis for managing resistant A. retroflexus and offers a potential target for the development of new herbicides.

The sole affiliated institution for this paper is the Institute of Plant Protection, Chinese Academy of Agricultural Sciences. Wang Ruolin and Cao Yi (master's students) are co-first authors, and Professor Huang Zhaofeng and Professor Li Xiangju are co-corresponding authors. This research was supported by the National Soybean Industry System of China.

Links: https://doi.org/10.1093/plphys/kiag140