Issue 9, 2023

Antifungal activity and mechanisms of AgNPs and their combination with azoxystrobin against Magnaporthe oryzae

Abstract

Silver nanoparticles (AgNPs) exhibit a broad spectrum of antimicrobial activity against various fungal pathogens, including the devastating rice blast fungus Magnaporthe oryzae, which threatens rice production worldwide. However, the antifungal molecular mechanisms of AgNPs against M. oryzae are still poorly understood. Here, it was found that the mycelial growth and virulence of M. oryzae strains were significantly reduced by AgNPs. Two nm-AgNPs at an EC50 concentration of 2.0 μg mL−1 almost impaired 100% virulence of M. oryzae. Further studies revealed that AgNP treatment changes cell wall morphology and suppresses appressorium formation. The defects in appressorium development upon AgNP treatment were caused by the reduced phosphorylation level of the MAPK MoPmk1 and impaired conidial autophagy. Importantly, the combination of AgNPs and azoxystrobin at appropriate ratios enhanced fungitoxicity to azoxystrobin-sensitive/resistant M. oryzae strains. Due to the excellent control effect of AgNPs on rice blast, we established a method for the biosynthesis of AgNPs by using the biocontrol Bacillus strain Tu27 to reduce waste environmental pollution and synthesis costs. Infection assays showed that the biosynthesized AgNPs displayed similar fungal toxicity. Taken together, our results revealed that AgNPs display the antifungal activity by a unique mechanism of damaging cell wall integrity, reducing phosphorylation of the MAPK MoPmk1, and impairing autophagy, and have an additive synergy with azoxystrobin on M. oryzae.

Graphical abstract: Antifungal activity and mechanisms of AgNPs and their combination with azoxystrobin against Magnaporthe oryzae

Supplementary files

Article information

Article type
Paper
Submitted
21 mar 2023
Accepted
20 jul 2023
First published
21 jul 2023
This article is Open Access
Creative Commons BY-NC license

Environ. Sci.: Nano, 2023,10, 2412-2426

Antifungal activity and mechanisms of AgNPs and their combination with azoxystrobin against Magnaporthe oryzae

H. Shi, H. Wen, S. Xie, Y. Li, Y. Chen, Z. Liu, N. Jiang, J. Qiu, X. Zhu, F. Lin and Y. Kou, Environ. Sci.: Nano, 2023, 10, 2412 DOI: 10.1039/D3EN00168G

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements