Termiticides are widely used to protect wooden houses from termites. Dieldrin, chlordane, heptachlor, and chlorpyrifos, which are effective termiticides, have been banned because of their high toxicity. Neonicotinoids, pyrethroids, phenyl pyrazoles, and triazoles have been used as alternatives to termiticides in indoor environments. However, despite numerous studies showing that farm-applied pesticides contaminate house dust, the health risks to humans from indoor termiticides remain unclear. We collected house dust and indoor air samples from 37 and 7 houses, respectively, to investigate the indoor termiticide contamination levels. The minimum margin of exposure to fipronil was 173, indicating that fipronil posed the highest risk among the targeted 28 compounds in indoor environment. The mean concentrations of alternative termiticides in house dust and air samples ranged from 1,126 ng g(- 1) (cyproconazole) to 5,356 ng g(- 1) (MGK-264) in thirty-seven houses and 0.08 ng m(- 3) (acetamiprid) to 34 ng m(- 3) (MGK-264) in seven houses, respectively. These results are comparable to the pesticide concentrations in houses close to farms where pesticides were applied, and are higher than atmospheric pesticide concentrations in oceans. Therefore, houses sprayed with termiticides may be as contaminated as agricultural environments where farmers apply substantial quantities of pesticides. The main route of exposure was air inhalation for fipronil, and both air inhalation and house dust ingestion for triazoles and potentiators. Establishment of regulations and development of decontamination methods are needed for indoor contamination of termiticides. Floor cleaning may be effective to remove termiticides that are ingested mainly through the house dust pathway.

IntroductionGarlic (Allium sativum L.) is renowned for its health-promoting properties, largely due to its sulfur-rich compounds. While copper is essential for plant growth and metabolism, excessive levels can disrupt cellular processes and lead to oxidative stress.ObjectivesThis study aims to investigate the impact of copper supplementation on the metabolic profile of garlic, with a particular focus on changes in sulfur metabolism.MethodsIto garlic cloves were harvested in 2020 on Red-Yellow Latosol soil. Copper chelate fertilizer was applied foliarly at 300 mL/ha, 30, 20, and 10 days before harvest. After harvesting, cloves were refrigerated and analyzed. Using LC-MS metabolomics, the metabolic profile of garlic was analyzed after copper supplementation to assess changes, specifically in sulfur-containing compounds.ResultsCopper supplementation led to a significant reduction in key sulfur-containing metabolites critical for the health-promoting properties of garlic, including allicin (FC = 0.0947), alliin (FC = 0.0147), and gamma-glutamyl-S-allylcysteine (FC = 0.0076). Enrichment analysis identified alterations in pathways related to glutamine, glutamate, alanine, and aspartate metabolism. Additionally, precursors of glutathione (GSH) were depleted, likely as a result of GSH sparing efforts to counteract copper-induced oxidative stress. This redirection may increase susceptibility to ferroptosis, a form of cell death linked to oxidative damage.ConclusionThe metabolomic analysis of copper-supplemented Ito garlic cloves showed a significant reduction in sulfur compounds allicin, alliin, and gamma-glutamyl-S-allylcysteine, important for organoleptic and medicinal properties. This decrease indicates a metabolic shift towards antioxidant defenses, with glutathione being redirected to defense pathways rather than secondary metabolites. Future studies should explore oxidative stress and ferroptosis markers, and lipidomics for a deeper understanding of garlic response to copper exposure.

In the past few decades, Cadmium-contaminated soil in agricultural fields has been a major global issue. The wide attention followed in agricultural production and the remediation of cadmium pollution in soil by cotton plants, due to the characteristics of wide planting area, the large biomass, strong capacity of cadmium accumulation, and non-edible properties of fiber. But the root secretion mechanism of cotton plants in response to cadmium threat is still unclear. In this study, four CdCl2 concentrations (0, 150, 300,450 mu mol/L) were applied to the soil at seedling stage, and physiological indicators of cotton seedling were detected and root exudates were collected after 10 days of cadmium exposure. The results showed that the cadmium tolerance of cotton seedlings was activated to the greatest extent under 300 mu mol/L cadmium, and inhibited when the concentration reached 400 mu mol/L. A total of 407 metabolites were detected based on UPLC-MS/MS. The composition and content of root exudates of cotton seedlings were significantly changed by cadmium stress, and there were 7 common differential accumulated metabolites, including isomaltulose, quinic acid, citric acid, gamma-aminobutyric acid, isomaltulose, galactinol and gluconic acid. KEGG analysis showed that there were 7 metabolic pathways highly related to cadmium stress, including pyruvate metabolism, glyoxylate and dicarboxylate metabolism, citrate cycle, galactose metabolism, starch and sucrose metabolism, ABC transporters and carbon metabolism. These metabolic pathways were involved in osmoregulation, energy supply and resilience in plants. In addition, exogenous addition of citric acid can enhance the antioxidant capacity of cotton leaves, and promote the absorption and accumulation of cadmium in cotton. This study provides a theoretical basis for further research on elucidating the response mechanism of root exudates in cotton plants to cadmium stress and for utilizing root exudates such as citric acid to alleviate cadmium stress.

Key messageMelatonin increases Pb tolerance in P. ovata seedlings via the regulation of growth and stress-related phytohormones, ROS scavenging and genes responsible for melatonin synthesis, metal chelation, and stress defense.AbstractLead (Pb) is a highly toxic heavy metal that accumulates in plants through soil and air contamination and impairs its plant growth and development. Because of its pharmaceutical importance, improvements in Plantago ovata yield against abiotic stresses are necessary. Melatonin (MEL) is a stress-alleviating biostimulator and our results showed a reduction in Pb induced phytotoxicity by enhancing plant growth attributes and balancing protective osmolytes. Pb-induced reactive oxygen species accumulation, including superoxide and peroxide free radicals and their mitigation through enzymatic antioxidants, was demonstrated in presence of MEL. Cell viability and Pb bioaccumulation were determined to understand the extent of cellular damage. Moreover, MEL increased secondary metabolite (flavonoids and anthocyanins) contents by 2-3-fold at the lowest Pb concentrations. Similar increases in the relative expression of genes (PoPAL and PoPPO), which are responsible for the production of non-enzymatic antioxidants, were observed. Notably, the upregulation of the PoCOMT gene up to 4-fold indicates increased melatonin production, as manifested in the phytomelatonin level. MEL supplementation also increased the auxin (IAA) level by 3-fold in the 100 mu M Pb treatment group, while the abscisic acid (ABA) level decreased (1.4-fold) and the expression of PoMYB (a stress-related transcription factor) increased (up to 2.66-fold). Additionally, we found extreme downregulation (up to 18-fold) in the relative expression of PoMT 2 (a metal binding thiol compound) with melatonin treatment, which is otherwise upregulated (by 6-fold) during Pb stress. In the current study, these effects collectively revealed that MEL contribute to enhanced plant growth and Pb stress tolerance.

Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 (Foc TR4), poses a significant threat to banana production globally, thereby necessitating effective biocontrol methods to manage this devastating disease. This study investigates the potential of Bacillus siamensis strain JSZ06, isolated from smooth vetch, as a biocontrol agent against Foc TR4. To this end, we conducted a series of in vitro and in vivo experiments to evaluate the antifungal activity of strain JSZ06 and its crude extracts. Additionally, genomic analyses were performed to identify antibiotic synthesis genes, while metabolomic profiling was conducted to characterize bioactive compounds. The results demonstrated that strain JSZ06 exhibited strong inhibitory activity against Foc TR4, significantly reducing mycelial growth and spore germination. Moreover, scanning and transmission electron microscopy revealed substantial ultrastructural damage to Foc TR4 mycelia treated with JSZ06 extracts. Genomic analysis identified several antibiotic synthesis genes, and metabolomic profiling revealed numerous antifungal metabolites. Furthermore, in pot trials, the application of JSZ06 fermentation broth significantly enhanced banana plant growth and reduced disease severity, achieving biocontrol efficiencies of 76.71% and 79.25% for leaves and pseudostems, respectively. In conclusion, Bacillus siamensis JSZ06 is a promising biocontrol agent against Fusarium wilt in bananas, with its dual action of direct antifungal activity and plant growth promotion underscoring its potential for integrated disease management strategies.

Root exudates play a pivotal role in belowground interactions in both ecological and agricultural contexts. The metabolic composition of exudates profoundly influences the dynamics of these interactions, thereby shaping the intricate relationships between plants, microbes, and soil environments. Recent advances in mass-spectrometry have facilitated the analysis of root exudate metabolic composition to a greater depth. Previously used methods primarily analyze root exudates in hydroponic systems, or employ hybrid methodologies, which cultivate plants in soil and transitioning them briefly to hydroponic systems for exudate collection. Modern day ecological studies demand that exudates are collected in their natural habitats, because this will provide a more ecologically meaningful exudate metabolic profile. However, collecting exudates from soil grown plants poses several challenges with regard to the collection procedures, amongst others, the need for recovery after excavation of the roots, the collection period, and the solution in which to collect. Here, we present an optimized, cost-effective protocol for root exudate collection from potted plants, which is readily adaptable to field-grown specimens. Using tomato plants grown in pots, we examined and optimized various parameters: the collection medium (water versus nutrient solution), the use of wetted glass beads versus roots submerged in water, the recovery phase post-substrate removal, and the duration of exudation. Employing liquid chromatography-mass spectrometry (LC-MS), we assessed total amount of exudate, the number of features and background noise. Subsequent to data processing and statistical analyses, we assessed the chemical classes within exudates and variations in key metabolites among the different methods. Our results showed that each of the tested parameters can influence the outcome in different ways. Omitting the recovery phase increased the numbers of features and exudate amounts, likely due to adding metabolites from damaged roots, whereas the exudation medium and the duration of exudation had fewer effects. Based on our results, we propose to collect exudates in beakers containing ultrapure water, and to collect exudates for 4 h after a 24 h recovery phase. This is a straightforward and economical approach for collecting root exudates from soil-grown plants which is suitable for LC-MS analysis.

利用高效液相色谱-质谱(HPLC-MS/MS)技术,对枇杷叶水提组分进行分析,并且对萜类物质进行解析。采用C18色谱柱(2.1 mm×100 mm,1.8μm),以水+0.1%甲酸溶液为流动相梯度洗脱,使用ESI离子源,在正、负离子模式下采集质谱数据,共检测到120个化合物;包括18种萜类化合物,总相对含量1452.693μg/mL;24种黄酮类化合物,总相对含量10378.081μg/mL;18种酚类化合物、总相对含量36967.955μg/mL;5种香豆素类化合物,总相对含量214.778μg/mL;进一步鉴定出18种萜类化合物的结构,主要包括乌苏烷型6种、齐墩果烷型7种、3种倍半萜、1种二萜类物质和1种特殊的环烯醚萜苷类物质;其中栎瘿酸、银杏内酯B、Prespatane、山栀苷甲酯、Icariside B5、皂皮酸、积雪草酸、18β-甘草次酸在以往的枇杷叶活性物质中未见报道。本文为枇杷叶水提成分的研究提供参考。