Functional genes of the methane biogeochemical cycle in forest and pastures areas in Amazon

Abstract

The Amazon Basin is covered by the largest existing rainforest, in which approximately 15% of its original cover was replaced by areas for supply the growing demand for food, in a process that changes the physical, chemical, and biological soil characteristics. The soil diversity is mainly composed of microorganisms of domains Archaea and Bacteria, required for the functioning of terrestrial ecosystems for their role in nutrient cycling and biogeochemical cycles. However, the anthropic use of soil has the potential to alter the microbiota structure and function and, consequently, these processes. Among them, the flow of methane (CH4), the second most important greenhouse gas, from the soil to the atmosphere presents high importance because it is directly related to the attributes of soil microbial community. Its flow is mainly controlled by methanogens, methane-producing archaea; and methanotrophic, bacteria that consume the same gas, which differ according to their unique ecological and biochemical characteristics. In this context, the quantitative real-time PCR (qPCR), which allows the calculation of the initial quantity of genes of interest in environmental samples, can be used to detect, quantify and temporally monitor the communities of methanogenic organisms, through the analysis of mcrA gene, and methanotrophic, through the analysis of pmoA and mmoX genes. The objective of the research project is to determine the land-use effect on the abundance of Archaea and Bacteria communities, with emphasis on functional genes related to the biogeochemical cycling of methane in the forest, secondary forest, and pasture areas in the state of Pará, in the eastern Amazon.