Kiwifruit is popular with consumers due to its unique flavor and high concentration of vitamin C, minerals, and other nutrients. As demand grows and the kiwifruit producing area in China expands, post-harvest rot diseases become more severe, with the average infected rate reaching 30% - 50%, and causing more than 100,000 tonnes of fruit losses per year, severely limiting the industry's healthy development.

Researchers from Wuhan Botanical Garden evaluated the antifungal activity and mechanism of silver nanoparticles (AgNPs) against four pathogens (Alternaria alternata, Pestalotiopsis microspora, Diaporthe actinidiae, and Botryosphaeria dothidea) causing kiwifruit post- harvest rot.

Results showed that AgNPs had distinct inhibitory effects on the mycelial growth and spore germination of four pathogens. It increased the permeability of cell membrane and leakage of intracellular substance, and caused cellular and organelle structural degradation. Moreover, the transcriptome sequencing of mycelium treated with AgNPs (24h/ 48h) was performed to reveal the molecular mechanism.

In addition, AgNPs remarkably reduced the infected phenotype and fluorescence symptoms, as well as the pathogen colonization and disease development of kiwifruit post- harvest rot with few Ag⁺ residue in the fruit’s peel or inner/ external pulp, indicating that AgNPs treatment was safe for kiwifruit.

The study verifified that AgNPs could be used to control kiwifruit rot disease, and laid the groundwork for the application of AgNPs to control other fruit fungal diseases.

This work was financially supported by the National Key Research and Development Program of Hubei province, the earmarked fund for China Agriculture Research System, the National Natural Science Foundation of China, and the Foundation of Wuhan Science and Technology Bureau.

Results have been published on Frontiers in Microbiology entitled “The antifungal activity and mechanism of silver nanoparticles against four pathogens causing kiwifruit post-harvest rot”.

The antifungal activity and mechanism of silver nanoparticles against four pathogens causing kiwifruit post- harvest rot (Image by WBG)