Functionalized biochar from waste as a slow-release nutrient source: Application on tomato plants.

Licorice processing waste was pyrolyzed at different temperatures (500 and 700 °C) to obtain biochar (BC500 and BC700) for use as a slow-release fertilizer on Solanum lycopersicum. The materials were characterized through BET analysis, SEM, elemental analysis, pHzc, and pyrolysis temperature effect was evaluated. The biochars were functionalized by the impregnation method to enrich them with nitrogen, phosphorus, and potassium (NPK), and desorption tests were performed in aqueous solution at different pHs (5 and 7). The pseudo-second-order model described well the release of all 3 macronutrients tested, BC500 was found to have slower release kinetics due to smaller pore size, reaching adsorption/desorption equilibrium after 14 days, compared with 10 for BC700, Kdes were lower in all 3 cases and NPK content was higher, initial pH did not change the release kinetics. BC500 was selected as an agricultural soil conditioner by testing at both different dosages of BC (0-25 %) and different NPK ratios (3:1:4 and 4:1:3). The treatment significance was evaluated. The best treatment resulted in BC dosage of 25 % nutrient ratio 4:1:3 which increased, compared to the control, total chlorophyll content (+38 %) and carotenoids (+15 %).

Xanthones: Biosynthesis and Trafficking in Plants, Fungi and Lichens.

Xanthones are a class of secondary metabolites produced by plant organisms. They are characterized by a wide structural variety and numerous biological activities that make them valuable metabolites for use in the pharmaceutical field. This review shows the current knowledge of the xanthone biosynthetic pathway with a focus on the precursors and the enzymes involved, as well as on the cellular and organ localization of xanthones in plants. Xanthone biosynthesis in plants involves the shikimate and the acetate pathways which originate in plastids and endoplasmic reticulum, respectively. The pathway continues following three alternative routes, two phenylalanine-dependent and one phenylalanine-independent. All three routes lead to the biosynthesis of 2,3',4,6-tetrahydroxybenzophenone, which is the central intermediate. Unlike plants, the xanthone core in fungi and lichens is wholly derived from polyketide. Although organs and tissues synthesizing and accumulating xanthones are known in plants, no information is yet available on their subcellular and cellular localization in fungi and lichens. This review highlights the studies published to date on xanthone biosynthesis and trafficking in plant organisms, from which it emerges that the mechanisms underlying their synthesis need to be further investigated in order to exploit them for application purposes.

Poly-(lactic-co-glycolic) Acid Nanoparticles Entrapping Pterostilbene for Targeting Aspergillus Section Nigri.

Poly-(lactic-co-glycolic) acid (PLGA) is a biodegradable, biosafe, and biocompatible copolymer. The Aspergillus section Nigri causes otomycosis localized in the external auditory canal. In this research, Aspergillus brasiliensis, a species belonging to the Nigri section, was tested. Coumarin 6 and pterostilbene loaded in poly-(lactic-co-glycolic) acid nanoparticles (PLGA-coumarin6-NPs and PLGA-PTB-NPs) were tested for fungal cell uptake and antifungal ability against A. brasiliensis biofilm, respectively. Moreover, the activity of PLGA-PTB-NPs in inhibiting the A. brasiliensis infection was tested using Galleria mellonella larvae. The results showed a fluorescence signal, after 50 nm PLGA-coumarin6-NPs treatment, inside A. brasiliensis hyphae and along the entire thickness of the biofilm matrix, which was indicative of an efficient NP uptake. Regarding antifungal activity, a reduction in A. brasiliensis biofilm formation and mature biofilm with PLGA-PTB-NPs has been demonstrated. Moreover, in vivo experiments showed a significant reduction in mortality of infected larvae after injection of PLGA-PTB-NPs compared to free PTB at the same concentration. In conclusion, the PLGA-NPs system can increase the bioavailability of PTB in Aspergillus section Nigri biofilm by overcoming the biofilm matrix barrier and delivering PTB to fungal cells.

A novel approach to control Botrytis cinerea fungal infections: uptake and biological activity of antifungals encapsulated in nanoparticle based vectors.

Botrytis cinerea, responsible for grey mold diseases, is a pathogen with a broad host range, affecting many important agricultural crops, in pre and post harvesting of fruits and vegetables. Commercial fungicides used to control this pathogen are often subjected to photolysis, volatilization, degradation, leaching, and runoff during application. In this context, the use of a delivery system, based on poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) represents an innovative approach to develop new pesticide formulations to successfully fight B. cinerea infections. In order to study NPs uptake, B. cinerea conidia and mycelium were treated with PLGA NPs loaded with the high fluorescent probe coumarin 6 (Cu6-PLGA NPs) and analyzed under ApoTome fluorescence microscopy. The observations revealed that 50 nm Cu6-PLGA NPs penetrated into B. cinerea conidia and hyphae, as early as 10 min after administration. Pterostilbene, a natural compound, and fluopyram, a synthetic antifungal, were entrapped in PLGA NPs, added to B. cinerea conidia and mycelium, and their antifungal activity was tested. The results revealed that the compounds loaded in NPs exhibited a higher activity against B. cinerea. These results lay the foundations for the use of PLGA NPs as a new strategy in plant pest management.

Remediation of hexavalent chromium contaminated water through zero-valent iron nanoparticles and effects on tomato plant growth performance.

Contaminated water with hexavalent chromium Cr(VI) is a serious environmental problem. This study aimed to evaluate the Cr(VI) removal by zero valent iron nanoparticles (nZVI) reduction process and the impact of Cr(VI), nZVI and combined treatment with nZVI and Cr(VI) on tomato growth performance. To evaluate the Cr(VI) toxic effect on germination capability, seeds were exposed to increasing Cr(VI) concentrations up to 1000 mg L-1. The inhibition of seed germination and the decrease of hypocotyl and root length started from Cr(VI) 5 mg L-1. Under treatment with Cr(VI) + nZVI 5 mg L-1, seed germination, hypocotyl and root length resulted significantly higher compared to Cr(VI) 5 mg L-1 treatment. The impact of only nZVI was investigated on chlorophyll and carotenoid in leaves; iron levels in leaves, roots, fruits and soil; carotenoid, fat-soluble vitamin and nicotianamine in mature fruits. A significant increase of leaf chlorophyll and carotenoids was observed after nZVI 5 mg L-1 treatment compared to controls. No significant variations were observed in carotenoids, fat-soluble vitamins and nicotianamine levels after treatment with nZVI 5 mg L-1 in mature fruits. For their ability to reduce Cr(VI) and to stimulate tomato growth, nZVI might to be considered as alternative for remediation purposes.