Control of Fusarium wilt of lisianthus by reassembling the microbial community in infested soil through reductive soil disinfestation.

Continuous monocropping often influences negatively the soil microbial community and leads to the occurrence of soil-borne diseases. In this study, a pre-cultivation soil management strategy, reductive soil disinfestation (RSD), involving amendment by the use of reed straw, bagasse, and rice straw, and creating anaerobic soil conditions, was used to regulate the microbial community in a soil infested by Fusarium wilt of lisianthus and make it suitable for plant cultivation. The results showed that RSD significantly decreased F. oxysporum population by 97.1%-99.1% and the incidence of lisianthus wilt disease to 3.0%-14.3% compared with that of the untreated soil. The lowest disease incidence was found in the soil treated with RSD where bagasse was incorporated. The replantation of the host plant differently stimulated the pathogen proliferations across the different soils. MiSeq sequencing and culture-dependent investigation showed that the RSD treatments established distinct microbial communities compared to that of the untreated soil. Furthermore, the relative abundances of representatives of the families Cytophagaceae, Chitinophagaceae, Chaetomiaceae, and an unclassified family within Sordariomycetes, as well as soil microbial activity and the proportions of antagonists were significantly and negatively correlated with the pathogen population increase. Overall, the RSD treatment contributed to the reassembly of the soil microbiome which contained more beneficial agents that successfully controlled the pathogen inoculum level and lisianthus Fusarium wilt disease.