Unravel dynamic of microbial community and metabolic structure in pesticide-contaminated rice paddies in Thailand

Rice production in Thailand has shifted from traditional to commercial farming to support the rapid increase in population and consumption. Different types of pesticides have been imported into Thailand to protect crops and to increase agricultural productivity. Herbicides and insecticides are used prior to rice seeding, during cultivation and onward to harvesting. The application of chemical agents has caused a shift in the ecosystems, affecting health, community composition, as well as the behavior of organisms ranging from prokaryotes to eukaryotes. Many studies conducted in Thailand have investigated the effect of pesticides on human health, pesticide management, and policymaking. However, the knowledge of the effect of pesticides on soil microbial community is limited. Soil microbes play a crucial role in the soil ecosystem that directly contributes to plant growth, development, and yield, so it is important to understand the effects of pesticides on soil microbiome to allow us to move away from unsafe usage of pesticides and perhaps to find a new solution. In this study, we investigated the effect of pesticides on the dynamic of microbial community and metabolic structure in rice paddies. Soil samples were collected from eight different harvesting rice fields, where four are conventional practices with pesticide applications and four are certified organic rice fields. Collectioned were performed at three time points. Soil samples were subjected to nucleic acid extraction and amplification. Microbial community structures were determined by 16S rRNA sequence analysis, and metabolic structure was predicted from 16S rRNA gene amplicon library of each sample using PICRUSt. The results provided an overall picture of microbial diversity and activity between the two different cultivation practices.