Related Experiment Video
Updated: Nov 18, 2025
Microfluidic Tools for Probing Fungal-Microbial Interactions at the Cellular Level
Published on: June 23, 2022
Antagonistic Activity of Bacteria Isolated from Apple in Different Fruit Development Stages against Blue Mold Caused
Rocío Crystabel López-González1, Yara Suhan Juárez-Campusano1, José Luis Rodríguez-Chávez1
1División de Estudios de Posgrado, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro 7600, México.
Abstract:
Blue mold caused by Penicillium expansum is one of the most significant postharvest diseases of apples. Some microorganisms associated with the surface of ripening apples possess the ability to inhibit the growth of P. expansum. However, the existing literature about their colonization in the stages before ripening is not explored in depth. This study aims to characterize the antagonistic capacity of bacterial populations from five fruit development stages of 'Royal Gala' apples. The results have shown that the density of the bacterial populations decreases throughout the ripening stages of fruit (from 1.0 × 105 to 1.1 × 101 cfu/cm2). A total of 25 bacterial morphotypes (corresponding to five genera identified by 16S RNA) were differentiated in which Bacillus stood out as a predominant genus. In the in vitro antagonism tests, 10 Bacillus strains (40%) inhibited the mycelial growth of P. expansum from 30.1% to 60.1%, while in fruit bioassays, the same strains reduced the fruit rot ranging from 12% to 66%. Moreover, the bacterial strains with antagonistic activity increased in the ripening fruit stage. B. subtilis subsp. spiziennii M24 obtained the highest antagonistic activity (66.9% of rot reduction). The matrix-assisted laser desorption ionization- time of flight mass spectrometry analysis revealed that bacteria with antagonistic activity produce antifungal lipopeptides from iturin and fengycin families.
Insights
Certain apple surface bacteria, particularly Bacillus strains, can inhibit blue mold (Penicillium expansum). This study found these beneficial microbes increase during fruit ripening, offering a natural disease control strategy.
Area of Science:
- Microbiology
- Plant Pathology
- Agricultural Science
Background:
- Blue mold, caused by *Penicillium expansum*, is a major postharvest apple disease.
- Microbial antagonists on apple surfaces can inhibit *P. expansum* growth.
- Limited research exists on pre-ripening fruit microbial colonization and antagonism.
Purpose of the Study:
- Characterize the antagonistic capacity of bacterial populations across five developmental stages of 'Royal Gala' apples.
- Identify specific bacterial genera and species with inhibitory effects against *P. expansum*.
- Investigate the relationship between fruit ripening stage and antagonistic bacterial abundance.
Main Methods:
- Sampling bacterial populations from 'Royal Gala' apples at five distinct fruit development stages.
- Isolation and identification of bacterial morphotypes using 16S rRNA gene sequencing.
- *In vitro* antagonism assays against *P. expansum* mycelial growth.
- Fruit bioassays to evaluate rot reduction.
- Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) for metabolite analysis.
Main Results:
- Bacterial population density decreased significantly during apple ripening (1.0 × 10^5 to 1.1 × 10^1 cfu/cm^2).
- Twenty-five bacterial morphotypes were identified, with *Bacillus* being the predominant genus.
- Ten *Bacillus* strains (40%) demonstrated significant *in vitro* inhibition (30.1–60.1%) and fruit rot reduction (12–66%).
- Antagonistic bacterial activity increased in later ripening stages, with *B. subtilis* subsp. *spiziennii* M24 showing the highest efficacy (66.9% rot reduction).
- Antagonistic bacteria produced antifungal lipopeptides, including iturin and fengycin families.
Conclusions:
- Bacterial populations on apples exhibit antagonistic potential against *Penicillium expansum*.
- *Bacillus* species, particularly *B. subtilis* subsp. *spiziennii*, are effective biocontrol agents for apple blue mold.
- The abundance and efficacy of these beneficial bacteria increase during fruit ripening, suggesting a natural defense mechanism.
- Antifungal lipopeptides produced by these bacteria are key to their inhibitory action.
Related Concept Videos
01:29Fungal Group Zygomycota
01:28Antimicrobial Effectiveness
01:23Antimicrobial Proteins
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...