Ecological Toxicity Alleviation of Imazethapyr to Non-target Plant Wheat: Active Regulation Between Auxin and DIMBOA

Abstract

A new perspective was put forward to alleviate the potential toxicity of herbicide (R)-imazethapyr ((R)-IM) to non-target plant wheat by active regulation between auxin and secondary metabolite 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazine-3(4H)-one (DIMBOA) in this study. (R)-IM effortlessly disrupted the balance between wheat growth and defense, which not only reduced 32.4% auxin content in wheat leaves, but also induced 40.7% DIMBOA accumulation compared to the control group. Transcriptomic results indicate that restoration of the auxin level in plants promotes the up-regulation of growth-related genes and increased accumulation of DIMBOA increases the expression of defense-related genes. Auxin and DIMBOA are in two divergent paths and alleviate herbicide stress on wheat primarily through effects on growth and defense, respectively. Additionally, as a common precursor of both auxin and DIMBOA, indole adopted a combined growth and defense strategy in response to (R)-IM toxicity, i.e., both restoring growth development and enhancing the defense system. It might be possible to find appropriate ways to regulate the plant growth-defense balance under herbicide stress by regulating auxin and DIMBOA levels in plants. Our insight into the interference mechanism of herbicides to the plant growth-defense system will facilitate the design of improved strategies for herbicide detoxification.