Metabolism Difference Is Involved in Mesosulfuron-Methyl Selectivity between Aegilops tauschii and Triticum aestivum

Abstract

The acetolactate synthase (ALS) inhibitor mesosulfuron-methyl is currently the only selective herbicide to control Aegilops tauschii in wheat fields; however, the mechanism underlying this selectivity remains unclear. Results showed that the tolerance of Triticum aestivum to mesosulfuron-methyl was much higher than that of A. tauschii. Mesosulfuron-methyl inhibited the in vitro ALS activity of A. tauschii and T. aestivum similarly, but the predicted structural interactions of ALS with mesosulfuron-methyl and induced expression of als were different in the two species. Compared with T. aestivum, A. tauschii was found to absorb more mesosulfuron-methyl and metabolize much less mesosulfuron-methyl. The cytochrome P450 monooxygenase (CYP450) inhibitor, malathion, greatly increased the sensitivity of T. aestivum to mesosulfuron-methyl, while its synergistic effect was smaller in A. tauschii. Finally, 19 P450 genes were selected as candidate genes related with metabolism-based mesosulfuron-methyl selectivity. Collectively, different sensitivities to mesosulfuron-methyl in the two species were likely to be attributed to metabolism variances.

Physiological Basis for the Mechanism of Selectivity of Tripyrasulfone between Rice (Oryza sativa) and Barnyard Grass (Echinochloa crus-galli)

“…Clearly, there were some differences in tripyrasulfone tolerance between rice and barnyard grass, and clarifying the mechanisms of the differences in tolerance will contribute to the rational design of new herbicidal compounds against some malignant/resistant weeds. 40 Sequence Alignment Analysis of the HPPD Protein and Molecular Docking Study of the HPPD Protein with HDT. One HPPD protein for rice (NP 001396268.1) and one HPPD protein for barnyard grass (scaffold48.278) were obtained from the NCBI and EnsemblPlants databases, respectively.…”

“…55,56 In addition, the selectivity of mesosulfuron-methyl, as the only selective herbicide that is effective in treating Aegilops tauschii in wheat fields, was also related to its relatively high and rapid degradation in wheat (Triticum aestivum), mediated by P450 genes. 40 These detoxifying metabolic enzymes serve as the basis for crop herbicide selectivity and are of great significance in agriculture due to their natural metabolic processes. 57 For example, different P450 monooxygenases metabolize HPPD inhibitors in maize, 22 cinnamycin in wheat, 58 ALS inhibitors in rice, 59 and other mode-of-action herbicides in different crops at a faster rate than in weeds.…”

“…Currently, tripyrasulfone is the only HPPD-inhibiting herbicide with POST application that can selectively control grass weed species in direct-seeded rice fields. Clearly, there were some differences in tripyrasulfone tolerance between rice and barnyard grass, and clarifying the mechanisms of the differences in tolerance will contribute to the rational design of new herbicidal compounds against some malignant/resistant weeds …”

“…For example, the metabolism of the ACCase inhibiting herbicide diclofop-methyl to nontoxic metabolites in wheat occurred via P450-mediated aryl hydroxylation, followed by glucose conjugation, likely mediated by GT . Moreover, atrazine selectivity was caused by the distinctly increased GST activity in maize. , In addition, the selectivity of mesosulfuron-methyl, as the only selective herbicide that is effective in treating Aegilops tauschii in wheat fields, was also related to its relatively high and rapid degradation in wheat (Triticum aestivum), mediated by P450 genes . These detoxifying metabolic enzymes serve as the basis for crop herbicide selectivity and are of great significance in agriculture due to their natural metabolic processes .…”