Work

Sustainable control of Phytophthora capsici in bell pepper using encapsulated Limosilactobacillus fermentum and reduced fungicide doses

Year: 2026

Type: article

Abstract: Phytophthora capsici causes severe losses in pepper cultivation, and sustainable biocontrol strategies are needed to reduce reliance on chemical fungicides. This study reports the isolation and functional evaluation of a lactic acid bacterium (Limosilactobacillus fermentum GS-15) from traditional yogurt, with proven antagonistic activity against P. capsici. The strain was identified via 16 S rRNA sequencing and assessed through in vitro assays, including dual culture and volatile organic compound (VOC) production. GS-15 inhibited P. capsici mycelial growth by 50.0%, while VOCs produced by GS-15 reduced growth by 38.9%. Exogenous lactic acid at a 90% concentration inhibited fungal growth by 88.9%, indicating the sensitivity of the pathogen to lactic acid. To enhance bacterial stability in the presence of chemical fungicide Previcur Energy®, the GS-15 was encapsulated in calcium–alginate beads. This encapsulation preserved viability and enhanced antagonistic activity to 61% inhibition. Greenhouse experiments using three bell pepper cultivars showed that GS-15 application significantly reduced disease incidence compared to untreated or fungicide-only treatments. The combination of GS-15 and a half-dose of fungicide reduced disease incidence to ≤ 10%, surpassing the performance of full-dose fungicide. Alginate-encapsulated GS-15 alone or with half-dose fungicide resulted in complete disease suppression in all cultivars tested. These results demonstrate that GS-15, especially when encapsulated, is an effective biocontrol agent. Its positive action with reduced fungicide inputs provides a promising tool for integrated pest management in sustainable pepper production. To the best of our knowledge, this study shows, for the first time, the potential of a human probiotic for controlling phytopathogenic P. capsici.

Source: Scientific Reports

DOI: 10.1038/s41598-026-39603-3

Authors: Maryam Abdollahi, Somayeh Rahaiee, Yousef Nami, Fatemeh Khelghatibana, Leila Ma’mani, Akram Sadeghi

Institutions: Amol University of Special Modern Technologies, Agricultural Research & Education Organization, Agricultural Biotechnology Research Institute of Iran, Iranian Research Institute of Plant Protection

Language: English

Topic: Plant-Microbe Interactions and Immunity

Subfield: Plant Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDGs: Zero hunger, Responsible consumption and production

Open Access status: gold

Estimated APC paid: $2,690