Role of Mycorrhizae and Phosphorus in the Nodulation and Growth of Barbatimão (Stryphnodendron adstringens)

• Grant number: 24/08765-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2024
• End date: July 31, 2025
• Field of knowledge: Biological Sciences - Botany - Pant Physiology
• Principal Investigator: Sarah Caroline Ribeiro de Souza
• Grantee: Ana Thereza dos Santos Dias
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Stryphnodendron adstringens (Mart.) Coville, commonly known as barbatimão, is a pioneer species native to the Brazilian cerrado. While it has been extensively studied for its pharmacological properties, there is limited research on its physiology. This leguminous species engages in symbiotic relationships with soil bacteria, known as rhizobia, which fix atmospheric nitrogen (N2), forming nodules on the roots and supplying the plant with nitrogen. Additionally, S. adstringens forms symbiotic associations with arbuscular mycorrhizal fungi in its roots. These fungi enhance the host plants' phosphorus (P) uptake, a nutrient that is typically scarce in cerrado soils. Preliminary studies in our laboratory suggest that nodulation in barbatimão may depend on mycorrhizal colonization of the roots, potentially linked to phosphorus absorption. Given the importance of these mutualistic interactions for barbatimão, our project aims to evaluate the effects of mycorrhizae and phosphorus on the nodulation and growth of this species. We will implement seven treatments: four involving different sources of phosphorus and combinations (mineral fertilizers, mycorrhizae, and biofertilizers), two negative controls (one without any microorganisms, and one with only rhizobia), and one treatment with non-autoclaved original soil retaining native microbiota, without added fertilizers or microorganisms. Seeds will be sown directly in pots and maintained in a greenhouse under natural light and temperature conditions. Germination rates will be analyzed, and after approximately 120 days, the plants will be harvested for further analyses. Growth parameters will be assessed, including fresh and dry biomass and leaf area. Root colonization by mycorrhizal fungi will be examined, and nitrogen metabolism will be evaluated by measuring total nitrogen content, ureides, total free amino acids, and total proteins in different plant organs. Additionally, total phosphorus content in the aerial parts will be analyzed. This study aims to identify the most effective treatment for barbatimão nodulation and to elucidate the role of phosphorus in this process.