Fermentation Optimization, Fungistatic Effects and Tomato Growth Promotion of Four Biocontrol Bacterial Strains

• Main Authors: Yao Zhang, Xingyuan Wang, Sibo Liang, Yuying Shi, Xiuling Chen, Jiayin Liu, Aoxue Wang
• Format: Article
• Language: English
• Published: MDPI AG 2021-07-01
• Series: Agriculture
• Subjects: tomato gray mold; tomato leaf mold; biocontrol bacteria; liquid fermentation; growth promotion
• Online Access: https://www.mdpi.com/2077-0472/11/7/686

Tomato is a widely cultivated crop that is important for its nutritional value and genetic diversity. Tomato production is seriously challenged by pests and diseases, among which tomato gray mold and leaf mold are particularly serious. Biological control is one of the most preferred methods for disease management in tomato production. At present, the fungi used to control tomato gray mold are mainly Trichoderma and yeast. <i>Bacillus</i> and actinomycetes are the most effective microorganisms for controlling tomato leaf mold. Tomato gray mold and leaf mold often occur at the same time during the production process, yet there are fewer strains for controlling both diseases at the same time. Biocontrol bacteria <i>Pseudomonas azotoformans</i> WXCDD51, <i>Bacillus</i> sp. WXCDD105, <i>Bacillus subtilis</i> BS and <i>Bacillus amyloliquefaciens</i> BS WY-1, which were isolated and screened in the previous stage, can prevent both tomato gray mold and leaf mold. Here, we optimized liquid fermentation for the four biocontrol bacterial strains together. We obtained the best fermentation medium formula and fermentation conditions for the four biocontrol bacteria. The broad-spectrum properties of the four biocontrol bacteria were tested, and, on this basis, compound strains were constructed. The control effect of single and compound strains on tomato gray mold and leaf mold was evaluated. Their potential effects on the growth of tomato seeds and seedlings were also studied. This research provides a foundation for the development and use of compound bacteria for growth promotion and disease management in tomato production.