Formulation of biofungicides based on Streptomyces lincolnensis strain SZ03 spores and efficacy against R. solani damping-off of tomato seedlings

Abstract

This work aimed to explore an antagonistic actinobacterial strain isolated from roots of Ziziphus lotus in bioformulation processes and the biocontrol of Rizoctonia solani damping-off of tomato seedlings. The strain Streptomyces lincolnensis SZ03 was investigated for the principal in vitro biocontrol mechanisms and then formulated in three different biofungicides Wettable Talcum Powder (WTP), Sodium-Alginate Propagules (SAP) and Clay Sodium-Alginate Propagules (CAP). Compared to a marketed control products (Serenade® and Acil 060FS®), the formulated biofungicides were investigated against the R. solani damping-off of tomato cv. Aïcha seedlings. The strain S. lincolnensis SZ03 produced chitinases, cellulases, β-1,3-glucanases, cyanhydric acid and siderophores and it showed strong antagonistic effect on the mycelial growth of R. solani. Bioautographic and HPLC analysis revealed the production of a single antifungal compound. The biofungicide WTP showed an attractive biocontrol effect by reducing significantly the disease severity index (DSI) compared to untreated seeds. No significant differences were obtained compared to the chemical treatment with Acil 060FS®. The viability of spores and biocontrol efficacy of the WTP were confirmed after one year storage. S. lincolnensis strain SZ03 has never been reported in the biocontrol of phytopathogenic fungal diseases and it open up very attractive prospects in the fields of biocontrol and crop improvement.

Current Review of Mycotoxin Biodegradation and Bioadsorption: Microorganisms, Mechanisms, and Main Important Applications

“…Recently, novel biofungicide formulations based on Bacillus subtilis 5, Bacillus cereus 3S5, and Pseudomonas fluorecens 10S2 were produced [175]. The same formulation has been created using other microorganisms [176][177][178].…”