Search Results (6)

Mesotrione is a triketone herbicide widely used for weed control in maize (Zea mays L.). In a bioassay conducted under controlled conditions, the simulated residual effects of mesotrione on leafy vegetables, including chard, lettuce, spinach, and endive were evaluated. The herbicide was applied at nine concentrations (0–240 µg a.i./kg soil), with the highest corresponding to the recommended field application rate. Nonlinear regression analysis was used to describe the relationship between morphological (shoot fresh weight) and physiological (pigment content) parameters as a function of herbicide dose. Shoot fresh weight was a more sensitive parameter than pigment content with mean EC₅₀ ± SE values of 23.9 ± 3.5 (chard), 34.3 ± 7.7 (lettuce), 13.2 ± 2.4 (spinach), and 990.3 ± 3921.5 (endive) µg a.i./kg soil, indicating that spinach is the most sensitive and endive the most tolerant species. A mesotrione residue level equivalent to EC₂₀ for shoot fresh weight corresponds to approximately 2, 4, 6, and 29% of the recommended application rate of mesotrione at which spinach, chard, lettuce, and endive (respectively) can be safely sown. Therefore, spinach, chard, and lettuce are not suitable substitutes for maize when the latter fails and should not be sown after silage maize. In such cases, only endive appears to be a viable alternative without the risk of crop injury. Full article

Meeting the rising demand for staple grains now requires cultivars that combine high yield, enhanced nutritional value, and strong chemical resilience. Blue-kernel landraces from central Mexico are rich in anthocyanins yet remain highly susceptible to post-emergence herbicides, whereas modern hybrids detoxify these compounds through cytochrome P450 (CYP450) enzymes. We crossed the anthocyanin-rich variety Polimaize with a CYP450-tolerant hybrid and evaluated the two parents and their F₁ segregants (designated “White” and “Yellow”) under greenhouse applications of mesotrione (75 g a.i. ha⁻¹), nicosulfuron (30 g a.i. ha⁻¹), and their mixture. Across 160 plants, the hybrid retained 95% of control dry matter and showed ≤7% foliar injury under all treatments, whereas Polimaize lost 28% biomass and exhibited 36% injury after nicosulfuron. The Yellow class matched hybrid performance while maintaining a blue pericarp and a β-carotene-rich endosperm, demonstrating that nutritional and agronomic traits can be stacked. The White class displayed heterosis-driven compensatory growth, exceeding its untreated biomass by 60% with nicosulfuron and by 82% with the mixture despite transient bleaching. Chlorophyll and carotenoid fluorescence revealed rapid, zeaxanthin-linked photoprotection in all tolerant genotypes, consistent with accelerated CYP450-mediated detoxification. These findings show that broad-spectrum herbicide tolerance can be introgressed into pigment-rich germplasm through conventional breeding, providing a non-transgenic path to herbicide-ready, anthocyanin-rich maize. The strategy preserves local biodiversity while delivering cultivars suited to intensive, weed-competitive agriculture and offers a template for integrating metabolic resilience into other native crops. Full article

Fenoxaprop-P-ethyl (FE) can effectively control weeds in rice fields, but it has been found to cause phytotoxicity in rice. In this study, the phytotoxicity of FE was mitigated by perilla leaf essential oil (PEO) in rice seedlings. The injury recovery rates (IRRs) for shoot length and fresh weight treated with 800 mg/L of PEO were 101.51% and 99.05%, respectively. Moreover, the damage of s-metolachlor and pretilachlor was also alleviated when co-applied with 800 mg/L PEO; the IRR of s-metolachlor phytotoxicity was 26.07% and 27.34%, respectively, and the IRR of pretilachlor phytotoxicity was 127.27% and 124.39%, respectively. However, PEO had no significant effect on the phytotoxicity of pinoxaden, mesotrione, penoxsulam, mesosulfuron-methyl, and nicosulfuron. The results of GC–MS analysis showed that a total of 23 components were detected in PEO, among which linalool (36.49%), linalyl formate (26.96%), α-terpineol (10.63%), 2-hexanoylfuran (5.81%), geranyl acetate (4.13%), and neryl acetate (2.30%) were the primary components. Among them, 2-hexanoylfuran was the most effective component to alleviate FE damage, for which the IRR of shoot length and fresh weight was 73.17% and 73.02%, respectively, followed by the geranyl acetate, for which the IRR was 72.32% and 60.56%, respectively, and neryl acetate, for which the IRR was 65.28% and 58.11%, respectively. Furthermore, the application of 50 mg/L of 2-hexanofuran significantly improved the tolerance of shoot length and fresh weight to FE stress by factors of 5.32 and 5.35, respectively. This research demonstrates that PEO and 2-hexanoylfuran have the potential to serve as natural safeners to reduce phytotoxicity. Full article

Green foxtail is a troublesome weed in crop fields across China. A nova target HPPD inhibitor is widely used to control weeds in agricultural production. Mesotrione, an HPPD inhibitor, cannot control green foxtail effectively under the recommended field dose, indicating that green foxtail is tolerant to mesotrione. Interestingly, a green foxtail biotype that exhibits a greater tolerance to mesotrione (GR₅₀ value 463.2 g ai ha⁻¹) than that of the wild biotype (GR₅₀ value 271.9 g ai ha⁻¹) was found in Jilin Province, China. The HPPD genes isolated from the two biotypes genome were aligned, while no difference was found in the amino acid of the HPPD compared with that of the wild biotype. Through the qPCR experiment, the HPPD gene copy number variation and overexpression were also not found. Cytochrome P450 inhibitors (malathion and PBO), pretreatment, could effectively reverse the tolerance. Compared with the MT biotype, the in vivo activity of P450s was higher after the mesotrione treatment in the HT biotype. Therefore, P450s might be involved in the mechanism of tolerance. Full article

Mesotrione is a widely used post-emergence herbicide for maize. The toxicity of mesotrione to maize (especially sweet corn) has been widely reported, and some sweet corn varieties are highly sensitive to mesotrione, which affects subsequent plant growth periods. However, the molecular mechanisms responsible for the differences in susceptibility to mesotrione are not known. By comparing changes in the transcriptome of mesotrione-tolerant line 301 and mesotrione-sensitive line 276 after mesotrione treatment, we found that the genes coding light-harvesting chlorophyll protein complex were induced in 301, and the genes coding loosening cell walls were overrepresented in 276. The net photosynthetic rate, maximum photochemical efficiency of leaf PSII, photochemical quenching of chlorophyll fluorescence, and the electron transport rate were significantly higher in 301 than in 276 after mesotrione treatment, and these effects became more severe as time passed. In addition, oxidative balance was also affected by mesotrione. Compared with 301, SOD, POD, and CAT activities were significantly reduced with longer exposure time in 276. The results suggested that sweet corn can mitigate herbicide mesotrione toxicity by improving photosynthesis, ROS scavenging, and cell wall synthesis. Full article

Bermuda grass (Cynodon dactylon) is notoriously difficult to control with some commonly used herbicides. We cloned a cytochrome P450 gene from Bermuda grass, named P450-N-Z1, which was found to confer tolerance to multiple herbicides in transgenic Arabidopsis. These herbicides include: (1) acetolactate synthase (ALS) inhibitor herbicides nicosulfuron and penoxsulam; (2) p-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide mesotrione; (3) synthetic auxin herbicide dicamba; (4) photosynthesis inhibitor bentazon. We further generated transgenic soybean plants expressing P450-N-Z1, and found that these transgenic soybean plants gained robust tolerance to nicosulfuron, flazasulfuron, and 2,4-dichlorophenoxyacetic acid (2,4-D) in greenhouse assays. A field trial demonstrated that transgenic soybean is tolerant to flazasulfuron and 2,4-D at 4-fold and 2-fold the recommended rates, respectively. Furthermore, we also demonstrated that flazasulfuron and dicamba are much more rapidly degraded in vivo in the transgenic soybean than in non-transgenic soybean. Therefore, P450-N-Z1 may be utilized for engineering transgenic crops for herbicide tolerance. Full article