Assessing the Influence of Fumigation and Bacillus Subtilis-Based Biofungicide on the Microbiome of Chrysanthemum Rhizosphere

Abstract

Chrysanthemum is an important ornamental species in China. However, sustained monoculture often leads to a decline in soil quality, in particular to the build-up of pathogens. Fusarium wilt, a severe disease in chrysanthemum monoculture systems, was effectively controlled by fumigation and/or the application of a biofungicide in our previous study. However, the mechanisms underlying disease suppression remain elusive. Here, a series of greenhouse experiments were conducted to characterize the effect on the chrysanthemum rhizosphere microbiome of the fumigant dazomet (DZ) and of a biofungicide based on Bacillus subtilis NCD-2 (BF). The results indicated that the BF treatment increased bacterial diversity by 4.2%, while decreasing fungal diversity by 21.3%. After two seasons of BF treatment, the abundance of microbes associated with disease suppression such as Bacillus spp. and Trichoderma spp. increased 15.1-fold and 4.25-fold more than that of the control, while the pathogenic Fusarium oxysporum was decreased by 79.20% when compared to the control. Besides, the DZ treatment reduced both bacterial and fungal diversity 7.97% and 2.73% respectively, when compared with the control. The DZ treatment controlled Fusarium wilt disease and decreased the abundance of F. oxysporum in the first year, but the abundance of the F. oxysporum was 43.8% higher after two years in treated soil than in non-treated soil. Therefore, the application of BF has a great potential for the control of Fusarium wilt disease in chrysanthemum by changing soil microbiome structure and function.

Changes in the Fungal Community Assembly of Apple Fruit Following Postharvest Application of the Yeast Biocontrol Agent Metschnikowia fructicola

“…In this regard, Zhimo et al [5] reported a similar reduction in the richness of the fungal community in strawberry fruit treated with M. fructicola. The reduction in fungal diversity following the application of biological control agents has also been reported in other crops, such as tea (Camellia sinensis) leaves, as a result of the application of Serendipita (=Piriformospora) indica [24], and in the rhizosphere of chrysanthemum (Chrysanthemum morifolium) following the application of Bacillus subtilis NCD-2 [25]. In contrast, under natural conditions of cold storage, the diversity of microbes has been shown to increase with time [26], and our result also showed marginal increases in diversity with an increase in storage time in untreated fruit as compared with water-treated or biocontrol-treated fruit, where the diversity remained stable.…”

Soil and Phytomicrobiome for Plant Disease Suppression and Management under Climate Change: A Review

“…This resistance can necessitate increased pesticide application, which in turn can have detrimental effects on soil health, human well-being, and the overall environment [ 93 ]. (2) Reduced fertility: pesticides can negatively impact soil fertility by harming beneficial microorganisms responsible for maintaining soil health and nutrient levels [ 129 , 130 ]. (3) Pesticides can also have adverse effects on the diversity of microorganisms in the soil, resulting in a loss of biodiversity and a decline in the overall health and productivity of the ecosystem.…”

Effects of Different Fumigants on the Replanted Soil Environment and Growth of Malus hupehensis Rehd. Seedlings

“…Meng et al (2019) found that dazomet fumigation affected primarily the characteristics of fungi, and could reduce the number of Fusarium oxysporum-a pathogenic bacteriumand improve the yield of watermelon. Chen et al (2019) found that dazomet fumigation reduced significantly the number of bacteria and fungi in replanted soil and controlled chrysanthemum fusarium wilt effectively. 1,3-Dichloropropene, a soil fumigant and nematicide, is used primarily for strawberries, sweetpotatoes, melons, flowers, and other crops before planting, soil fumigation, and processing; it has been shown to be effective in controlling worms, plant pathogenic bacteria, and weeds (Qiao et al, 2010).…”