Journal of Agricultural and Food Chemistry最新文献

Phytophagous insects are more predisposed to evolve insecticide resistance than other insect species due to the "preadaptation hypothesis". Cytochrome P450 monooxygenases have been strongly implicated in insecticide and phytochemical detoxification in insects. In this study, RNA-seq results reveal that P450s of Spodoptera litura, especially the CYP3 clan, are dominant in cyantraniliprole, nicotine, and gossypol detoxification. The expression of a Malpighian tubule-specific P450 gene, SlCYP9A75a, is significantly upregulated in xenobiotic treatments except α-cypermethrin. The gain-of-function and loss-of-function analyses indicate that SlCYP9A75a contributes to cyantraniliprole, nicotine, and α-cypermethrin tolerance, and SlCYP9A75a is capable of binding to these xenobiotics. This study indicates the roles of inducible SlCYP9A75a in detoxifying man-made insecticides and phytochemicals and may provide an insight into the development of cross-tolerance in omnivorous insects.

Aflatoxin B₁ is a notorious mycotoxin with mutagenicity and carcinogenicity, posing a serious hazard to human and animal health. In this study, an AFB₁-degrading dipeptidyl-peptidase III mining from Aspergillus terreus HNGD-TM15 (ADPP III) with a molecular weight of 79 kDa was identified. ADPP III exhibited optimal activity toward AFB₁ at 40 °C and pH 7.0, maintaining over 80% relative activity at 80 °C. The key amino acid residues that affected enzyme activity were identified as H450, E451, H455, and E509 via bioinformatic analysis and site-directed mutagenesis. The degradation product of ADPP III toward AFB₁ was verified to be AFD_1. The zebrafish hepatotoxicity assay verified the toxicity of the AFB₁ degradation product was significantly weaker than that of AFB₁. The result of this study proved that ADPP III presented a promising prospect for industrial application in food and feed detoxification.

Peanut southern blight, caused by the soil-borne pathogen Sclerotium rolfsii, is a widespread and devastating epidemic. Frequently, it is laborious to effectively control by labor-intensive foliar sprays of agrochemicals due to untimely find. In the present study, seed treatment with physcion (PHY) at doses of 0.08, 0.16, and 0.32 g AI kg^-1 seed significantly improved the growth and photosynthetic activity of peanuts. Furthermore, PHY seed treatment resulted in an elevated enzymatic activity of key enzymes in peanut roots, including peroxidase, superoxide dismutase, polyphenol oxidase, catalase, lipoxygenase, and phenylalanine ammonia-lyase, as well as an increase in callus accumulation and lignin synthesis at the infection site, ultimately enhancing the root activity. This study revealed that PHY seed treatment could promote the accumulation of reactive oxygen species, salicylic acid (SA), and jasmonic acid (JA)/ethylene (ET) in peanut roots, while also decreasing the content of malondialdehyde levels in response to S. rolfsii infection. The results were further confirmed by transcriptome data and metabolomics. These findings suggest that PHY seed treatment activates the plant defense pathways mediated by SA and JA/ET in peanut roots, enhancing the resistance of peanut plants to S. rolfsii. In short, PHY is expected to be developed into a new plant-derived immunostimulant or fungicide to increase the options and means for peanut disease control.

A dynamic gastrointestinal digestion system (simgi) after a human oral phase was used, for the first time, to assess the bioaccessibility of plant sterols (PS) from wholemeal rye bread (74.8 ± 2.2 mg of PS/100 g d.m.) and PS-enriched wholemeal rye bread (PS-WRB) (1.6 ± 0.04 g of PS/100 g of fresh bread). The use of these solid food matrices requires a novel adaptation of the gastric phase of the system. The PS identified in the breads are campesterol, campestanol, stigmasterol, β-sitosterol, sitostanol, Δ5-avenasterol, Δ5,24-stigmastadienol, Δ7-stigmastenol, and Δ7-avenasterol. The bioaccessibility of the total PS, only quantifiable in PS-WRB, is 19.9%, with Δ7-avenasterol being the most bioaccessible and Δ5-avenasterol being the least (p < 0.05). As shown in this study, PS-WRB can be considered to be a good choice to include in the daily diet. Furthermore, although the use of dynamic digestion methods for evaluating bioaccessibility implies high costs and technical complexity, their application means a closer approximation to in vivo scenarios.

Multiprotein bridging factor 1 (MBF1) is a very important transcription factor (TF) in plants, whose members influence numerous defense responses. Our study found that MBF1c in Cucurbitaceae was highly conserved. CsMBF1c expression was induced by temperature, salt stress, and abscisic acid (ABA) in cucumber. Overexpressed CsMBF1c enhanced the heat resistance of a cucumber, and the Csmbf1c mutant showed decreased resistance to high temperatures (HTs). CsMBF1c played an important role in stabilizing the photosynthetic system of cucumber under HT, and its expression was significantly associated with heat-related TFs and genes related to protein processing in the endoplasmic reticulum (ER). Protein interaction showed that CsMBF1c interacted with dehydration-responsive element binding protein 2 (CsDREB2) and nuclear factor Y A1 (CsNFYA1). Overexpression of CsNFYA1 in Arabidopsis improved the heat resistance. Transcriptional activation of CsNFYA1 was elevated by CsMBF1c. Therefore, CsMBF1c plays an important regulatory role in cucumber's resistance to high temperatures.

Enzymatic oxygenation of various cyclic ketones into lactones via Baeyer-Villiger monooxygenases (BVMOs) could provide a promising route for synthesizing fragrances and pharmaceutical ingredients. However, unsatisfactory catalytic activity and thermostability restricted their applications in the pharmaceutical and food industries. In this study, we successfully improved the catalytic activity and thermostability of a Baeyer-Villiger monooxygenase (OgBVMO) from Oceanicola granulosus by reshaping the binding pocket. As a result, mutant OgBVMO-Re displayed a 1.0- to 6.4-fold increase in the activity toward branched cyclic ketones tested, accompanied by a 3 °C higher melting point, and a 2-fold longer half-life time (t_1/2 (45 °C)). Molecular dynamics simulations revealed that reshaping the binding pocket achieved strengthened motion correlation between amino acid residues, appropriate size of the substrate-binding pocket, beneficial surface characteristics, lower energy barriers, and shorter nucleophilic distance. This study well demonstrated the trade-off between the enzyme activity and thermostability by reshaping the substrate-binding pocket, paving the way for further engineering other enzymes.

UV can serve as an effective light spectrum for regulating plant secondary metabolites, while relevant studies on UV-A are much less extensive than those on UV-B. A comprehensive understanding of the selective effects of UV-A on different secondary metabolites and the specific features of primary metabolism that drive these effects is still lacking. To address this knowledge gap, we conducted a study to analyze the dynamic changes in the metabolome and transcriptome of lettuce leaves irradiated with red plus UV-A light (monochromatic red light as control). Generally, UV-A promoted the synthesis of most phenylpropanoids and terpenoids originating from the shikimate and methylerythritol phosphate (MEP) pathway in plastids but sacrificed the synthesis of terpenoids derived from the mevalonate (MVA) pathway, particularly sesquiterpenes. Increased precursors supply for the shikimate and MEP pathway under UV-A was directly supported by the activation of the Calvin-Benson cycle and phosphoenolpyruvate transport. Whereas, along with phosphoenolpyruvate transport, the TCA cycle was restrained, causing deprivation of the MVA pathway precursor. In addition, UV-A also activated the plastidic oxidative branch of the pentose phosphate pathway, photorespiration, and malate shuttle, to ensure a sufficient supply of nitrogen, circulation homeostasis of the Calvin-Benson cycle, and energy balance, thus indirectly supporting UV-A-induced specific secondary metabolic output. This study provides a comprehensive framework for understanding the flexible primary-secondary metabolism interactions that are able to produce specific metabolites favorable for adaptation to environmental stimuli.

The residues of acifluorfen present a serious threat to the agricultural environment and sensitive crops. DnrA, a nitroreductase, is an intracellular enzyme that restricts the application of wild-type Bacillus sp. Za in environmental remediation. In this study, two strategies were employed to successfully secrete DnrA in strains SCK6 and Za, and the secretion expression conditions were optimized to achieve rapid degradation of acifluorfen. Under the optimal conditions, the relative activities of the DnrA supernatant from strains SCK6-D and Za-W were 3.06-fold and 3.53-fold higher than that of strain Za, respectively. While all three strains exhibited similar tolerance to different concentrations of acifluorfen, strains SCK6-D and Za-W demonstrated significantly faster degradation efficiency compared to strain Za. Furthermore, the DnrA supernatant from strains SCK6-D and Za-W could effectively reduce the toxicity of acifluorfen on maize and cucumber seedlings. This study provides an effective technical approach for the rapid degradation of acifluorfen.