Abstract

MORILLO DE LOS SANTOS, Alfonso et al. Isolation and characterization of PGPR bacteria associated with bell pepper (Capsicum annuum Group) in Greenhouse. RIIARn [online]. 2025, vol.12, n.2, pp.32-40. ISSN 2409-1618.  https://doi.org/10.53287/isqx6729sx27h.

The use of plant growth promoting rhyzobacteria (PGPR) represents a sustainable alternative in agricultural production, especially in areas with international requirements for sustainable practices. Peppers produced in greenhouses in the Dominican Republic are one of the fastest-growing and most profitable crops in recent decades. The research aimed to isolate and characterize PGPR bacteria and evaluate their potential biostimulant effect on pepper crops. Root samples were collected from healthy pepper plants produced in greenhouses in the provinces of Azua, San José de Ocoa, and La Vega, Dominican Republic. Endophytic bacteria were isolated, purified, and identified by DNA extraction, 16S rRNA gene sequencing, and compared with Gene Bank data. Biochemical tests were performed. One hundred and seventy-seven bacteria were isolated by molecular sequencing, eight of which were found to be PGPR. These included Bacillus siamensis, Pseudomonas atacamensis, Rhizobium oryzihabitans, Bacillus haikouensis, Antribacter gilvus, Enterobacter ludwigii, Priestia aryabhattai, and Kosakonia pseudosacchari. These bacteria grew at different temperatures, pH, and salinity levels. Six were catalase-positive, and one produced siderophores. In greenhouse tests using a randomized block design, pepper plants were inoculated to evaluate height, stem thickness, and biomass. The bacteria showed significant differences compared to the unfertilized and uninoculated control. Although there were no significant differences compared to the fertilized control, a positive effect was observed, increasing plant development. The results suggest that species such as Bacillus siamensis have potential as biofertilizers due to their adaptation to environmental conditions and their biostimulating effect on plants.

Keywords : Bacillus siamensis; biostimulant; Fusarium oxysporum; Kosakonia pseudosacchari; Rhizobium oryzihabitans.

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