Diversity and function of microbiota associated with litter decomposition and carbon cycling in Amazonian soils.

• Grant number: 24/22161-0
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: March 28, 2025
• End date: September 28, 2025
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Tsai Siu Mui
• Grantee: Jéssica Adriele Mandro
• Supervisor: Geertje Franciska Veen
• Host Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Institution abroad: Royal Netherlands Academy of Arts and Sciences, Netherlands
• Associated to the scholarship: 23/02576-9 - Carbon cycling in degraded soils and its contribution to the regeneration of forests in the Eastern Amazon, BP.DR

Abstract

Preliminary results of the ongoing PhD project funded by FAPESP, project 2023/02576-9, indicated that land use changes occurring in the Eastern Amazon have the potential to alter soil microbial communities, which may influence carbon cycling in these soils. In particular, we observed significant effects of land-use changes on soil fungal communities, with an increase in the diversity of fungi and functional guilds associated with saprotrophic and pathotrophic traits in pasture. In our studies, we also verified that land use changes alter the chemical characteristics of the deposited litter, which further influenced soil properties. We also sought to understand how increased temperature, land use, and litter affect soil microbiota and its decomposition process through a microcosm experiment. By evaluating the functional profile of the microbial communities acting in the microcosms, we found that forest-to-pasture conversion and increased temperature modified the soil functional profile, increasing the consumption of different carbon sources in the pasture, while forest soils showed the opposite result. During the internship, metagenomic data from the studies will be analyzed using bioinformatics tools to investigate how soil microbial communities respond to changes in land use and rising temperatures caused by climate change. This approach will not only explore microbiological shifts but also assess their impacts on soil carbon cycling and storage. Advanced computational techniques will be employed to identify key microbial taxa and functional genes involved in these processes, providing a deeper understanding of their ecological roles and contributions to soil resilience under changing environmental conditions. Given the great importance of the Amazon and soil microbiota within the context of climate change and the need to understand the impacts caused by changes in land use on microbial communities and their potential for climate mitigation, studies within this context are still extremely relevant. Therefore, the main objectives of this internship proposal are i) to analyze and integrate the metagenomic datasets that will be obtained in Studies 1 and 2, developed within the scope of the FAPESP project 2023/02576-9; and ii) obtain and analyze genomes assembled from litter metagenomes from different land uses in Eastern Amazonia, obtained in Study 3, as well as evaluate the metabolic characteristics of microorganisms present in response to different land and litter uses, in order to identify the main metabolic pathways used. In addition, the structural equation model will also be used to evaluate the variation in the abundances of functional groups associated with litter in different land uses in the Eastern Amazon. (iii) Finally, in this internship proposal, the results obtained will also be integrated in order to investigate the dynamics of carbon cycling in Amazonian soils in the face of land use changes and climate change. This proposal is a collaboration between the Laboratory of Cellular and Molecular Biology of the University of São Paulo (USP-Brazil) and the Netherlands Institute of Ecology (NIOO-Netherlands), under the joint supervision of Dr. Siu Mui Tsai and Dr. Ciska Veen. This proposal is also affiliated with the American University, Washington DC, under the supervision of Adjunct Assistant Professor Andressa Monteiro Venturini, who serves as a co-advisor for the scholarship holder within the CENA/USP Graduate Program.