Botrytis cinerea is a primary pathogen causing stem and fruit rot during pre-and post-harvest. In the present study, the main purpose was to inquire into the antifungal activity and potential mechanisms of thymol and carvacrol against B. cinerea. During the experiment, the effects of thymol and carvacrol on physical and biochemical parameters of B. cinerea were evaluated. Results indicated that thymol and carvacrol exhibited strong antifungal activity against the targeted pathogen, with minimum inhibitory concentration and minimum fungicidal concentration of 65 mg/L and 100 mg/L for thymol, and 120 lL/L and 140 lL/L for carvacrol. Thymol and carvacrol changed obviously the morphology of B. cinerea hyphae by disrupting and distorting the mycelia through scanning electron microscopy. The membrane permeability of B. cinerea hyphae was prompted with the increment of two chemical agents' concentration, as evidenced by extracellular conductivity increase, the release of cell constituent, and the decrease of extracellular pH. Furthermore, a marked decline in total lipid content of B. cinerea cells was induced by the two chemical agents, suggesting that the cell membrane structures were destructed. Therefore, present results indicated that thymol and carvacrol may be used as a good alternative to conventional fungicides against B. cinerea in controlling grey molds in horticultural products.

BackgroundEssential oils from plants have been reported to have wide spread antimicrobial activity against various bacterial and fungal pathogens, and these include α-Phellandrene, Nonanal and other volatile substances. However, biological activities of α-Phellandrene and Nonanal have been reported only in a few publications. Further investigations are necessary to determine the antimicrobial activity of these compounds, especially for individual application, to establish the possible mechanism of action of the most active compound.ResultsThe results are shown that α-Phellandrene and Nonanal have a dose-dependent inhibition on the mycelial growth of Penicillium cyclopium. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) are 1.7 and 1.8 mL/L for α-Phellandrene, 0.3 and 0.4 mL/L for Nonanal, respectively. The volatile compounds altered the morphology of P. cyclopium hyphae by causing loss of cytoplasmic material and distortion of the mycelia. The membrane permeability of P. cyclopium increased with increasing concentrations of the two volatile compounds, as evidenced by cell constituent release, extracellular conductivity and induced efflux of K+. Moreover, the two volatile compounds induced a decrease in pH and in the total lipid content of P. cyclopium, which suggested that cell membrane integrity had been compromised.ConclusionsThe results demonstrated that α-Phellandrene and Nonanal could significantly inhibit the mycelia growth of P. cyclopium by severely disrupting the integrity of the fungal cell membrane, leading to the leakage of cell constituents and potassium ions, and triggering an increase of the total lipid content, extracellular pH and membrane permeability. Our present study suggests that α-Phellandrene and Nonanal might be a biological fungicide for the control of P. cyclopium in postharvest tomato fruits.

The study investigated the antifungal activity and potential antifungal mechanisms of volatile compounds (i.e., E‐2‐hexenal) against Penicillium cyclopium, one of the main tomato postharvest pathogens, which was obtained and purified from postharvest tomato surface. Experimental data suggested that the volatile compound exhibited strong antifungal activity against the targeted pathogens, with minimum inhibitory concentration and minimum fungicidal concentration of 160 μL/L and 320μL/L for E‐2‐hexenal, respectively. The membrane permeability of the P. cyclopium increased with increasing concentrations of E‐2‐hexenal, as evidenced by cell constituent release, leakage of potassium ions, and extracellular conductivity. Moreover, E‐2‐hexenal could induce a decrease in total lipid content and extracellular pH. These results suggest that the anti‐fungal activity of E‐2‐hexenal against P. cyclopium can be attributed to the disruption of the cell membrane integrity, the increase of membrane permeability and the leakage of cell components. Practical Applications Penicillium cyclopium was isolated from the surface of tomato fruits after harvest. E‐2‐hexenal had an inhibitory effect on the hyphae and spores of P. cyclopium. The minimum inhibitory concentration and minimum fungicidal concentration were determined by using different concentrations of E‐2‐hexenal against P. cyclopium. The study results indicate that the antifungal activity of E‐2‐hexenal against P. cyclopium can be attributed to the disruption of the cell membrane integrity, the increase of membrane permeability and the leakage of cell components. The study results provided a reference for extending the storage of tomato fruits.

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Members of the casein kinase 1 (CK1) family are evolutionarily conserved eukaryotic protein kinases involved in various cellular, physiological, and developmental processes in yeast. However, the biological roles of CK1 members in plants are poorly understood. Here, we report that an Arabidopsis CK1 member named casein kinase 1-like 8 (CKL8) was ubiquitously expressed in all plant organs, mainly in the stems of seedlings according to quantitative real-time PCR. Western blotting showed a remarkable expression of the AtCKL8 gene in transgenic plants induced by high salinity. A histochemical assay of AtCKL8 promoter::GUS expression revealed that the AtCKL8 promoter is very active in both seedlings and adult plants subjected to the salinity stress, while no GUS activity was detectable in all the transgenic plants grown under normal conditions. In a subcellular distribution analysis, the AtCKL8-GFP fusion protein was localized mainly in the cell membrane. AtCKL8-overexpressing transgenic plants showed an insensitivity to high salinity and an early flowering phenotype. Overall, these findings suggest that AtCKL8 plays a positive role in NaCl signaling and improves salt stress tolerance in transgenic Arabidopsis. ARTICLE HISTORY

The interface and surface acidity of heterogeneous catalysts are widely applied to manipulate the catalytic performance. However, the interface structure prepared by traditional synthesis processes required multistep procedures, which was still lack of controllability and stability. Here, we show a general synthetic approach to fabricate ultra-stable heterogeneous catalysts with tailored molecular interfacial structure and super acidity in one step. The as-synthesized SiW 12 O x /TiO 2 catalyst was used for photo-catalytic conversion of methane to value-added oxygenates. We propose that the formed molecular interface W 12 À OHÀ Ti coupled with the introduced Brønsted acid sites of POMs, results in enhancing the photocatalytic performance. Namely, the addition of SiW 12 O x can reduce the recombination of electrons and holes for triggering charge separation owing to the photoelectron capturing by proton, improving electron transfer to reactants and thereby promoting catalytic activity. This fabrication method provides a way to build molecular interface photo-catalyst by POMs with super acidity and ultrastable structure.

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