Effects of commercial organic fertilizers on disease resistance and rhizosphere microbiome composition in tomato plants

Organic fertilizers (OFs) are increasingly recognized not only as nutrient sources but also as amendments that can influence plant health by modifying the rhizosphere microbiome and stimulating plant defense mechanisms.
This study investigated the impact of different commercially available OFs on the immunity and disease resistance of tomato (Solanum lycopersicum) plants, as well as their effects on the microbial communities in the growing medium.
Tomato plants treated with certain OFs exhibited primed defense responses, characterized by enhanced expression of defense-related genes upon infection with Pseudomonas syringae pv. tomato DC3000. However, increased defense gene expression alone did not consistently correlate with reduced disease severity, emphasizing the importance of balanced nutrition.
Metabarcoding analyses revealed that OFs altered the rhizosphere microbiome by promoting specific bacterial taxa associated with plant defense stimulation.
The findings highlight the potential of OFs in integrated disease management strategies and underscore the significance of the rhizosphere microbiome in plant health.

IV International Symposium on Organic Greenhouse Horticulture

A. Barrada, R. Mahmoudi, N. Rochon, T.T.A. Nguyen, M. Dorais

organic amendments, organic farming, alfalfa meal, feather meal, soy cake, pelleted poultry manure, blood meal, bone meal, shrimp meal, Pseudomonas syringae

https://doi.org/10.17660/ActaHortic.2025.1428.2