TITLE:
Endophytic and Rhizosphere Bacteria from Opuntia dillenii (Ker-Gawl.) Haw (Cactaceae) as Biological Agents against Sclerotium rolfsii
AUTHORS:
Yves Kévin Brun, Marie Epiphane Dossoumou, Agossou Damien Pacôme Noumavo, Julien Colombet, Haziz Sina, François Lefort, Farid Baba-Moussa, Rachidatou Sikirou, Lamine Baba-Moussa
KEYWORDS:
Tomato, Sclerotium rolfsii, Biocontrol, Priestia flexa, Bacillus subtilis, Opuntia dillenii
JOURNAL NAME:
Agricultural Sciences,
Vol.17 No.6,
June
10,
2026
ABSTRACT: Tomato is a crop of major agronomic importance, severely affected by soil-borne diseases such as collar rot caused by Sclerotium rolfsii. This study aimed to evaluate the biocontrol potential of bacterial strains isolated from Opuntia dillenii in Benin against this pathogen. An in-vitro screening identified the most effective antagonistic strains, which were subsequently assessed under greenhouse conditions for their effects on disease incidence and plant growth. Under pathogen pressure, strong variability was observed among the tested strains. In-vitro, Bacillus subtilis S7 and Priestia flexa S6 showed the highest inhibition potential, with inhibition rates of 100% and 61.77%, respectively. In greenhouse conditions, B. subtilis C7 was the most effective treatment, reducing disease incidence by 80% compared to the inoculated control while maintaining shoot growth (height: 6.0%; number of leaves: 4.0%). In the absence of pathogen pressure, strain-dependent growth-promoting effects were observed. P. flexa C6 exhibited the strongest stimulatory effects on aerial growth, while B. subtilis C7 significantly enhanced root development (16.1%). These results highlight the strong biocontrol potential of selected bacterial strains against S. rolfsii, while also demonstrating their capacity to promote tomato growth under non-stress conditions.Graphical Abstract