Seasonal influence on soil microbial diversity and prospecting of plant growth-promoting bacteria in integrated systems in the brazilian Cerrado

• Grant number: 25/13978-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: November 01, 2025
• End date: July 31, 2028
• Field of knowledge: Agronomical Sciences - Agronomy - Soil Science
• Principal Investigator: Daniel Guariz Pinheiro
• Grantee: Gabriella Linhares de Andrade
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil
• Associated research grant: 21/10639-5 - Center for Research on Biodiversity Dynamics and Climate Change, AP.CEPID

Abstract

Integrated production systems represent a strategic approach to sustainable land use by combining agricultural, livestock, and forestry activities in the same area, thus promoting beneficial interactions within the agroecosystem. Soil harbors a vast biological diversity, particularly bacteria with the potential to promote plant growth and enhance tolerance to abiotic stresses such as drought, high temperatures, and salinity. In this context, this project aims to investigate the soil microbiome profiles in integrated production systems in the Brazilian Cerrado, in order to assess the influence of edaphoclimatic conditions across two distinct seasonal periods. In parallel, the project seeks to identify bacteria with plant growth-promoting potential. Soil samples will be collected from different integration systems during both dry and rainy seasons in the regions of Bom Jesus, in the state of Piauí, and Brejo, in the state of Maranhão. The study will be divided into three stages. The first stage will involve the assessment of microbial diversity, composition, differential abundance, taxonomic characterization, and functional prediction of bacteria and fungi using a metataxonomic approach, based on sequencing of the V3-V4 regions of the 16S rRNA gene (bacteria) and the ITS2 region of the 18S rRNA gene (fungi). The second stage will comprise bacterial tolerance assays under drought, saline, and thermal stresses, along with the evaluation of physiological traits, including enzymatic activities (cellulase, amylase, lipase, protease, and esterase), hemolytic activity, exopolysaccharide production, and biofilm formation. This stage will also include assays for ACC deaminase activity, solubilization of potassium, phosphorus, zinc, and iron, and production of indole-3-acetic acid (IAA). The most promising bacterial strains based on these characterizations will be identified at the species level through 16S rRNA gene sequencing. In the final stage, selected isolates will be tested in tomato plants (Micro-Tom cultivar) under stress conditions to evaluate their effects on plant growth promotion and oxidative stress mitigation, using morphological and biochemical analyses, respectively. The central hypothesis of this study is that the soils of integrated production systems in the Cerrado, influenced by seasonal conditions, harbor microbiomes with characteristic taxonomic and functional profiles, containing bacteria with biotechnological and agronomic potential capable of promoting plant growth and alleviating the effects of abiotic stresses.