Abstract
Disease-suppressive soils exist worldwide. However, the disease-suppression mechanism is unknown, and it's unclear how to produce such soils. The microbiota that develop in a multiple-parallel-mineralization system (MPM) can increase nutrient production efficiency and decrease root disease in hydroponic systems. Artificial media inoculated with MPM microorganisms can degrade organic matter to produce inorganic nutrients similarly to natural soil, but it's unknown whether they can also suppress pathogen growth. Here, we produced an artificial medium that inhibited root disease similarly to disease-suppressive soils. Microbial MPM culture solution was inoculated into non-soil carriers (rockwool, rice husk charcoal, and vermiculite) to test whether it could suppress growth of Fusarium oxysporum f. sp. lactucae J. C. Hubb. & Gerik. We inoculated F. oxysporum f. sp. conglutinans (Wollenweber) Snyder et Hansen strain Cong:11 and F. oxysporum f. sp. lactucae J. C. Hubb. & Gerik into artificial media sown each with Arabidopsis thaliana (L.) Heynh. and Lactuca sativa L. var. capitata supplemented with MPM culture microbes. The MPM microorganisms suppressed F. oxysporum f. sp. lactucae J. C. Hubb. & Gerik growth and prevented plant disease. Thus, MPM-inoculated non-soil carriers that can generate inorganic nutrients from organic matter may also suppress disease in the absence of natural soil. Our study shows novel creation of a disease-suppressive effect in non-soil media using the microbial community from MPM culture solution.