Comparative proteomic and physiological analyses reveal tribenuron-methyl phytotoxicity and nontarget-site resistance mechanisms in Brassica napus

The application of herbicides is the most effective strategy for weed control and the development of herbicide-resistant crops will facilitate the weed management. The acetolactate synthase-inhibiting herbicide, tribenuron-methyl (TBM), is broadly used for weed control. However, its application in rapeseed field is restricted since rapeseed is sensitive to TBM. Herein, an integrated study of cytological, physiological and proteomic analysis of the TBM-resistant rapeseed mutant M342 and its wild-type (WT) plants was conducted. After TBM spraying, M342 showed improved tolerance to TBM, and proteins implicated in non-target-site resistance (NTSR) to herbicides had a significantly higher level in M342 as compared with the WT. Differentially accumulated proteins (DAPs) between these two genotypes were enriched in glutathione metabolism and oxidoreduction coenzyme metabolic process, which protected the mutant from oxidative stress triggered by TBM. Important DAPs related to stress or defence response were up-accumulated in M342 regardless of the TBM treatment, which might serve as the constitutive part of NTSR to TBM. These results provide new clues for further exploration of the NTSR mechanism in plants and establish a theoretical basis for the development of herbicide-resistant crops.

Automated summary

The application of herbicides is an effective strategy for weed control, and the development of herbicide-resistant crops can enhance weed management. However, the use of the herbicide tribenuron-methyl (TBM) is limited in rapeseed fields due to rapeseed's sensitivity to TBM. A study was conducted on the TBM-resistant rapeseed mutant M342 and its wild-type plants, revealing that M342 exhibited improved tolerance to TBM and had higher levels of proteins related to non-target-site resistance (NTSR) to herbicides compared to the wild-type plants. Differentially accumulated proteins (DAPs) between the two genotypes were enriched in glutathione metabolism and oxidoreduction coenzyme metabolic process, providing protection against oxidative stress caused by TBM. These findings offer insights into the mechanism of NTSR in plants and contribute to the development of herbicide-resistant crops.