Assessment of morphophysiological and genotypic diversity of endophytic bacteria isolated from rice (Oryza sativa L.) plants

• Autor(a) principal: Leonardo-Silva, Lucas
• Data de Publicação: 2023
• Outros Autores: Silva, Larissa Batista da, Ferreira, Enderson Petrônio de Brito, Santos, Karina Freire d'Eça Nogueira, Naves, Plinio Lázaro Faleiro, Martin-Didonet (In memoriam), Claudia Cristina Garcia
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Revista Caatinga
• Texto Completo: https://periodicos.ufersa.edu.br/caatinga/article/view/11415
• topic: Arroz. Promoção de crescimento de plantas. PCR 16S-23S rDNA. Enzimas extracelulares.; ice. Plant growth promotion. PCR 16S-23S rDNA. Extracellular enzymes.

Rice production in Brazil incurs high costs due to the significant use of agrochemicals. Some plant growth-promoting rhizobacteria (PGPR) can be used as alternative to fertilizers and phytosanitary products. Thus, the objective of this study was to characterize endophytic bacteria isolated from roots of rice plants. The isolates were characterized based on colony morphology, antibiotic resistance, carbon sources utilization, enzyme activity (catalase, amylase, protease, cellulase, and lipase), inorganic phosphate solubilization, and the 16S-23S rDNA intergenic region. Morphologically, 68% of the isolates presented a rapid growth rate, 46% presented abundant mucus production, and 77% formed viscous colonies. All isolates were resistant to nalidixic acid and 16% presented resistance to streptomycin. The majority (90%) used monosaccharides and disaccharides in carbon source assays. Most of the isolates (95%) were positive for catalase and 63.6% were positive for amylase, protease, lipase, and cellulase activities. Additionally, 59% of them were able to solubilize phosphate. The mean enzymatic index for amylase, cellulase, and protease was 2.8, 3.5, and 1.7 respectively. The similarity analysis revealed high diversity among the isolates, with similarity indices of 70% (based on morphological characteristics) and 60% (based on the intergenic region 16S-23S rDNA). Considering morphophysiological and genotypic characteristics, three promising isolates should be evaluated in studies under field conditions for the potential development of bioproducts to replace industrially manufactured inputs in rice crops.