The silver nanoparticles (AgNPs) have become increasingly popular due to their demand in multipurpose sectors such as medicine, electronics, cosmetics, energy, agriculture, etc. However, our knowledge and understanding of the actual environmental impacts of biosynthesized AgNPs on the soil bacterial community functions are not sufficiently understood. 

In a study published in Journal of Environmental Management, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) highlighted the beneficial effects of biosynthesized AgNPs on the soil bacterial community structure and functions. 

The researchers isolated biosynthesized AgNPs from agricultural farm soil and further identified using 16S rDNA sequencing approach. Seed germination assay was then used to evaluate their effects on plant growth. 

The researchers also made an attempt to quantify certain bacterial functional genes involved in the nitrogen and phosphorus cycling to comprehend the possible impact of biosynthesized AgNPs application on microbial functions. They targeted a range of functional genes (NirK, NirS, NosZ, AOA, AOB and PhoD) involved in important soil ecological processes such as denitrification, nitrification and recycling of organic phosphorus 

Their results demonstrated more pronounced impact of AgNPs treatment on the targeted functional genes abundance after 30 days of application. The AgNO₃ treatment showed maximum toxic impact on functional genes abundance in comparison to control and AgNPs treatments.  

“This is the first empirical evidence to show the positive response of the soil bacterial community functions to the application of biosynthesized AgNPs, however, an important limitation is that our interpretation is based on one soil type. Therefore, future studies require elaborated experiments to evaluate nanotoxicity of biosynthesized nanoparticles under different soil conditions with varying properties such as pH, organic matter content, soil texture, water holding capacity, etc. across different spatial scales”, said Prof. YANG Xiaodong, correspondence author of the study. 

Contact 

YANG Xiaodong Principal Investigator  

Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China         

E-mail: yangxd@xtbg.ac.cn  

Positive response of soil bacterial community structure and functions to biosynthesized silver nanoparticles. (Image by Sandhya Mishra)