The biocontrol activity and chemical composition of the volatile organic compounds (VOCs) produced by Pseudomonas chlororaphis subsp. aureofaciens SPS-41 were investigated. The VOCs inhibited mycelial growth and spore germination in Ceratocystis fimbriata, which causes black rot disease in sweet potato tuber roots (TRs) and showed wide-spectrum antifungal activity against several plant pathogenic fungi. A microscopic examination of C. fimbriata cells suggested morphological changes and a loss of cellular contents. Different inoculation strategies significantly affected the antifungal activity of the VOCs. In the volatile profile of SPS-41, the most abundant compound, 3-methyl-1-butanol, followed by phenylethyl alcohol and 2-methyl-1-butanol showed strong inhibition toward C. fimbriata. The weight loss rate and disease severity of the TRs were significantly reduced in response to the VOCs emitted by SPS-41. The results suggest that the VOCs produced by P. chlororaphis subsp. aureofaciens SPS-41 might constitute an attractive biological fumigant for controlling black rot disease in sweet potato TRs.
Natamycin was encapsulated in gliadin-casein nanoparticles (G-C NPs) to control black rot in cherry tomato against Alternaria alternata . The G-C NPs with a mean particle diameter of 211 ± 4 nm were prepared using an anti-solvent method. The composite NPs showed better stability against neutral pH, ion, and storage than gliadin NPs. The quenching of gliadin by natamycin was static with a constant of 5.99 × 10 −12 M −1 ∙S −1 , and was spontaneous with a free energy of −23.5 kJ∙M −1 at 298 K. Both hydrophobic stacking and hydrogen bonds between natamycin and gliadin were found as the major driven force in the formation of the complex. The NPs kept the antifungal activity of natamycin with improved photostability. The NPs coatings exhibited better results than natamycin in controlling black rot on cherry tomato. This study shows the potential of the G-C NPs as all-natural delivery systems for natamycin in post-harvest treatments.
危险品化学品经营许可证（带存储）