# Indigenous Olive Orchard Bacteria as Biocontrol Agents: An Integrated Culture-Dependent and Soil Microbiome Approach

**Authors:** Clara M. Izquierdo-Jiménez, Cecilia Recuero, Sergi Maicas, Inmaculada del Castillo-Madrigal

PMC · DOI: 10.3390/microorganisms14020310 · Microorganisms · 2026-01-28

## TL;DR

This study explores bacteria in olive orchard soils that can fight harmful pathogens, suggesting a sustainable way to manage plant diseases.

## Contribution

The study identifies phenology-related shifts in soil microbiomes and isolates bacteria with antagonistic potential against olive pathogens.

## Key findings

- Higher cultivable bacterial diversity was observed during the fruit formation stage compared to the flowering stage.
- Certain bacterial strains showed antagonistic activity against olive pathogens.
- Soil microbiome analysis revealed taxa significantly enriched or depleted during olive fruit formation.

## Abstract

Olive orchard soils are a source of microorganisms capable of inhibiting major olive pathogens. In this study, rhizobacteria were isolated and characterized based on plant growth-promoting traits, and soil 16 rRNA gene sequencing analysis was performed to analyze microbial communities at two key olive phenological stages (flowering and fruit formation). Using a culture-dependent approach, a total of 90 bacterial isolates representing distinct colony morphotypes were recovered from olive soils, with 35 during the flowering stage and 55 during the fruit formation stage, indicating a higher cultivable diversity during the latter period. We identified some bacterial strains with antagonistic activity and observed phenology-related shifts in the soil microbiome. Using differential abundance analysis, we identified bacterial taxa that were significantly enriched or depleted during olive fruit formation. Overall, this study demonstrates that olive-associated bacteria harbor antagonistic potential against olive pathogens. The use of bacteria adapted to olive agroecosystems represents a promising strategy for sustainable disease management.

## Linked entities

- **Species:** Olea europaea (taxon 4146)

## Full-text entities

- **Diseases:** toxicity (MESH:D064420), fungal (MESH:D009181), bacterial diseases (MESH:D001424), tumor (MESH:D009369), Olive knot disease (MESH:C564931), phytopathogenic diseases (MESH:D004194), injury to (MESH:D014947), PGP (MESH:D006130), leaf lesions (MESH:D009059), peacock spot disease (MESH:D008796)
- **Chemicals:** Chromium azurol S (-), IAA (MESH:C030737), cycloheximide (MESH:D003513), lipopeptides (MESH:D055666), agarose (MESH:D012685), N2 (MESH:D009584), CAS (MESH:C015076), agar (MESH:D000362), NaCl (MESH:D012965), fengycins (MESH:C049972), Phosphate (MESH:D010710), copper (MESH:D003300), volatile organic compounds (MESH:D055549), iron (MESH:D007501)
- **Species:** Bacteria Latreille et al. 1825 (Bacteria stick insect, genus) [taxon 629395], Homo sapiens (human, species) [taxon 9606], Pseudomonas savastanoi (species) [taxon 29438], Clostridium (genus) [taxon 1485], Patescibacteria group (clade) [taxon 1783273], Bacillus mojavensis (species) [taxon 72360], Pseudomonas sp. 'olive' (species) [taxon 289358], Fonticella (genus) [taxon 1434004], Micrococcus (genus) [taxon 1269], Bacillota (clostridial firmicutes, phylum) [taxon 1239], Venturia oleaginea (species) [taxon 1898124], Solanum tuberosum (potatoes, species) [taxon 4113], Tepidimicrobium (genus) [taxon 285105], Pseudomonas protegens Pf-5 (strain) [taxon 220664], Bacillus amyloliquefaciens (species) [taxon 1390], Phytomonospora (genus) [taxon 1434030], Olea europaea (common olive, species) [taxon 4146], Actinomycetota (actinobacteria, phylum) [taxon 201174], Lysinibacillus (genus) [taxon 400634], Paenibacillus (genus) [taxon 44249], Chitinophagales (order) [taxon 1853229]

## Full text

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## Figures

3 figures with captions in the complete paper: https://tomesphere.com/paper/PMC12942659/full.md

## References

47 references — full list in the complete paper: https://tomesphere.com/paper/PMC12942659/full.md

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Source: https://tomesphere.com/paper/PMC12942659