Aislamiento y caracterización de bacterias promotoras de crecimiento vegetal asociadas a la rizosfera de Megathyrsus maximus

Abstract

Megathyrsus maximus (Guinea grass) is an important forage species for livestock production, whose productivity has been adversely affected by the excessive use of chemical fertilizers. The objective of this study was to isolate and characterize plant growth-promoting bacteria (PGPB) associated with the rhizosphere of M. maximus. Rhizosphere samples were collected and processed for bacterial isolation, followed by microbiological, biochemical, and molecular characterization. Plant growth-promoting traits were assessed through urease activity, phosphate solubilization, catalase activity, amylolytic activity, and indole-3-acetic acid (IAA) production. In addition, in vitro assays were conducted to evaluate seed germination, root length, leaf length, stem length, and fresh plant weight. The results demonstrated the successful isolation and identification of rhizosphere-associated bacteria with plant growth-promoting potential, regardless of their geographic origin, revealing considerable genetic diversity among the isolates. The best-performing strains were molecularly identified as Azospirillum lipoferum, Rhizobium etli, Klebsiella oxytoca, and Serratia marcescens. These findings highlight the potential of these bacterial species as biofertilizers to enhance the establishment, growth, and productivity of M. maximus, providing a sustainable alternative to reduce dependence on chemical fertilizers and supporting the development of more efficient and environmentally responsible livestock production systems under tropical conditions