**4. Conclusions**

The green synthesis of AgNPs is a safe alternative to physical and chemical methods. The present study reports for the first time the biosynthesis of AgNPs by using endophytic bacterium isolated from onion. The formation of biogenic AgNPs was further confirmed through UV-vis spectroscopy, FTIR, XRD, SEM, TEM and EDS. In addition, the biosynthesized AgNPs exhibited robust antifungal activity against rice blast pathogen *M. oryaze* strain Gry, which may be mainly attributed to their ability to inhibit spore germination, germ tube growth, appressorium formation and damage of cell well. Overall, these results suggest that biosynthesized AgNPs have the potential to protect rice plants from fungal diseases.

**Author Contributions:** Conceptualization, E.I. and J.L.; Methodology, E.I. and T.A.; Software, E.I. and J.L.; data Investigation, E.I. and J.L.; Supervision, C.Y., W.W. and B.L.; writing—original draft, E.I., T.A. and B.L.; Writing—review & editing, all the authors contribute to this part. All authors have read and agreed to the published version of the manuscript.

**Funding:** The work is partially supported by Shanghai Agriculture Applied Technology Development Program (2019-02-08-00-08-F01150), Zhejiang Provincial Natural Science Foundation of China (LZ19C140002), National Natural Science Foundation of China (31872017, 32072472, 31571971, 31801787, 31901925), Zhejiang Provincial Project (2017C02002, 2019C02006, 2020C02006), Key Scientific Technological Project of Ningbo (2016C11017; 2019B10004), National Key Research and Development Program of China (2018YFD0300900; 2017YFD0201104), Dabeinong Funds for Discipline Development and Talent Training in Zhejiang University, State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-products (2010DS700124-ZZ1907), the Fundamental Research Funds for the Central Universities.

**Acknowledgments:** We thank for the help in data investigation and analysis from Muchen Zhang, Arshad Ali, Mengju Liu and Solabomi Olaitan Ogunyemi.

**Conflicts of Interest:** The authors declare no conflict of interest.
