Biochar Amendment Suppressed <i>Fusarium</i> Wilt and Altered the Rhizosphere Microbial Composition of Tomatoes

Abstract

The effectiveness of biochar application to promote plant growth and suppress plant diseases is usually dependent on the application dose of the biochar. Here, we evaluated the effects of biochar supplied at 0%, 1%, 2%, and 3% (w/w) on tomato growth, Fusarium wilt disease severity, and rhizosphere microbial community diversity. We found that biochar applied at 1% and 2% promoted tomato growth and decreased the severity of Fusarium wilt disease. High-throughput amplicon sequencing indicated that 1% biochar decreased the alpha diversity and altered the composition of the bacterial and fungal community in the tomato rhizosphere, increasing the abundance of potential plant-beneficial microorganisms. Quantitative PCR confirmed that all doses of biochar increased the abundance of rhizosphere bacteria; biochar applied at 1% and 2% decreased the abundance of rhizosphere fungi and Fusarium oxysporum f. sp. Lycopersici (FOL), while biochar applied at 3% increased abundance of FOL. Our results indicated that biochar applied at 1% and 2% suppressed tomato Fusarium wilt disease, which might be linked to the change of the rhizosphere microbial community structure and increased the abundance of potential plant-beneficial microorganisms such as Pseudomonas sp. within the microbiome.

Keywords

• tomato
• biochar
• <i>Fusarium</i> wilt
• rhizosphere microbial communities