Ecological implications of the use of microbial inoculants in agricultural soils

Abstract

Microbial inoculants are increasingly used in agriculture. In general, these products have one or a few microbial species, previously isolated and characterized, and when applied to the soil help to promote plant growth and/or biocontrol of pest and pathogen. In this scenario, little is known about how soil management and microbial diversity can affect the establishment and survival of inoculants used in agriculture. Moreover, to date, there are no studies available in the literature that sought to understand how the native soil microbiota responds to the use of these products. Thus, in this research project, we propose to apply the concept of microbial invasion to better understand the action of inoculants in agricultural soils. For this, we will conduct experiments under controlled conditions to study the effect of (i) soil management, (ii) microbial diversity and (iii) the presence of plants on the establishment and survival of Azospirillum brasilense and Bacillus subtilis, and at the same time, we will monitor possible impacts that these inoculants may have on the native soil microbiota. The methodology to be used in this project is very comprehensive and makes use of complementary strategies. For this, the cultivation techniques will be used in combination with metabolic and enzymatic indicators, real-time quantitative PCR (qPCR) and high throughput sequencing of DNA (16S rRNA and ITS) of soil samples from different treatments. As for data analysis, multivariate statistics and network analysis will be used. Taken together, these techniques give the project great potential for accurately assessing the effect of different inoculants on the composition, structure, and activity of native soil microbiota, as well as providing a better understanding of how soil management and microbial diversity influence the establishment and survival of these microorganisms. Finally, the results obtained during this research project will be presented and discussed in scientific events and in the form of scientific articles to be submitted for publication in a scientific journal with editorial board. (AU)