Filogenia molecular de espécies de Eragrostis Ness (Poaceae) no pampa gaúcho

Abstract

The genus Eragrostis comprises grass species distributed globally, including Eragrostis plana (lovegrass), an invasive plant with significant ecological and economic impact in the Pampa Biome. The expansion of this species has caused environmental and productive losses, making it essential to understand its phylogenetic relationships with native species of the biome to develop future biotechnological tools for its management. This study aimed to investigate the phylogenetic proximity between E. plana and native Eragrostis species occurring in the pampas of the state of Rio Grande do Sul, Brazil, using the molecular markers ITS and rbcL. Eragrostis species were collected and identified in different locations across RS. DNA was extracted for polymerase chain reaction (PCR) amplification using primers for ITS and rbcL, aiming to reconstruct phylogenetic trees through the Maximum Likelihood Method. The results based on the ITS marker indicated that E. plana forms a monophyletic group distinct from native species, suggesting significant genetic divergence and a closer relationship with E. lehmanniana, which originates from the African continent, like the invasive species. Native species of the Pampa Biome, such as E. bahiensis, E. neesii, and E. lugens, exhibited greater genetic similarity among themselves, forming a more cohesive group distinct from E. plana. This suggests that these species share a most recent common ancestor, distinct of the African species. The ITS marker demonstrated greater discriminatory power in recovering phylogenetic relationships within the genus, discriminating the analyzed species with better resolution, while rbcL showed lower resolution with reduced bootstrap values. The genetic characterization performed in this study contributes to the understanding of Eragrostis evolution and provides essential information for future strategies to manage the invasive species.