Two fungal isolates, F12-20 and F3-1, were collected from postharvest blueberry in China. By phylogenetic analysis with the nuclear ribosomal internal transcribed spacer region and morphological analyses, they were initially identified as Penicillium and Arthrinium sacchari ( A. sacchari ). The results showed that water-soluble chitosan (WCS) and sulfonated chitosan (SCS) could significantly reduce the radial growth of fungal mycelia. The best concentrations were 0.25 and 16 g L –1 for WCS and 0.50 and 64 g L –1 for SCS against Penicillium sp. and A. sacchari , respectively. Importantly, SCS exhibited selective antifungal activity against Botrytis cinerea and A. sacchari . As different species of fungi may respond differently to fungicides, the findings of this study will provide a basis for the development of target-specific pathogen control and will be useful in designing and implementing fungicide resistance management for control postharvest decay, thus extending the storage life of fresh blueberry. Practical application Experimental results obtained herein are useful for designing and implementing fungicide resistance management for control postharvest decay in blueberry to improve marketable fruit and extend the storage life of fresh blueberries. And sulfonated chitosan can be applied to the target-specific pathogen control.
Diseases caused by tuber fungi severely disrupt the storage life and quality of post-harvest Gastrodia elata ( G. elata ). Herein, it was found that the decay of G. elata tubers is primarily attributed to Fusarium solani and Penicillium crustosum . To inhibit postharvest rotting in G. elata tubers, microwave-treatment (MT) was employed as a disinfection method. However, they could not be completely inhibited by a single MT in vivo test, which were at various power levels (300, 500, 700 W) and durations (20, 30, 40 s). Hence, MT (700w, 30s) combined with modified atmosphere packaging (MAP) was employed, which were polyethylene films of varying thickness (20, 30, 40 μm), and its efficiency was validated. Results indicate that the combined treatment improved the quality of infected G. elata tubers. In addition, it decreased 79.81% in decay volume of G. elata tubers compared with the control group. Further results indicate that the reactive oxygen species and energy metabolism pathways of G. elata tubers were activated by the combined treatment, activating the enzyme activity and relative expression of superoxide dismutase, catalase and peroxidase and maintaining the levels of ATP, ADP and energy charge. Taken together, these results indicate that MT combined with MAP is a new and effective method for the post-harvest preservation of tubers and root crops.
This work fabricated natamycin-loaded zein-casein nanoparticles (N-Z/C NPs) by a pH-driven approach and applied to control postharvest peach brown rot caused by Monilinia fructicola . When casein and phosphoric acid were used as a stabilizer and neutralizing acid, respectively, NPs with mean particle sizes < 100 nm and zeta-potentials < −30 mV could be obtained. The NPs could increase the aqueous dispersibility of natamycin and showed high stability against environmental changes, which could be attributed to both hydrophobic stacking and hydrogen bonds between natamycin and zein. Besides, the effects of N-Z/C NPs on the storage of peach were assessed in vitro and in vivo . Nanoencapsulation did not affect the antifungal activities of natamycin. The NPs with 20 and 80 µg/mL of natamycin could basically inhibit the spore germination and mycelial growth of M. fructicola , respectively. The N-Z/C NPs coatings exhibited better results than natamycin in controlling of peach brown rot.
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