Association mapping in the investigation of Paspalum grass resistance to leaf spot (Bipolaris spp.)

• Grant number: 24/23682-4
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: May 01, 2025
• End date: April 30, 2028
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Anete Pereira de Souza
• Grantee: Geovani Luciano de Oliveira
• Host Institution: Centro de Biologia Molecular e Engenharia Genética (CBMEG). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Company: Ministério da Agricultura, Pecuária e Abastecimento (Brasil). Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA). Embrapa Sede
• Associated research grant: 22/04006-2 - Center for Plant Molecular Breeding (CeM²P), AP.PCPE

Abstract

Tropical forages are plants of great importance for national livestock production, playing a crucial role in Brazil's economy. The native genus Paspalum stands out as a promising option for the development of forage cultivars due to its adaptability to diverse ecosystems, broad genetic diversity, and potential as a source of agronomically valuable genes applicable to other tropical grasses. However, the productivity and quality of these plants are often compromised by fungal foliar diseases, particularly leaf spot caused by Bipolaris spp.. This disease affects plant development, reducing biomass and forage quality. Although preliminary studies suggest varying levels of resistance within the Paspalum genus, no genomic regions have yet been identified, nor have the molecular mechanisms underlying resistance been elucidated. Understanding the genetic architecture of resistance to this disease is essential for developing resistant cultivars, representing a sustainable strategy from both economic and environmental perspectives. In this context, this project proposes a genome-wide association study (GWAS) using a diversity panel of 312 Paspalum spp. genotypes to identify genomic regions associated with leaf spot resistance and elucidate the underlying mechanisms involved. The panel will be phenotyped for leaf spot resistance over two years, and SNP (Single Nucleotide Polymorphism) markers will be obtained through genotyping-by-sequencing (GBS). Simultaneously, Bipolaris spp. isolates will be characterized both morphologically and molecularly to precisely identify the species. This project has the potential to identify molecular markers that will facilitate the early selection of superior genotypes resistant to this pathogen, as well as generate valuable knowledge for the development of advanced biotechnological strategies applicable to other tropical grass genera. The results will significantly contribute to improving the productivity, quality, and sustainability of Brazilian livestock production.