Fig. 2: Effects of metabolites addition on plant disease occurrence and microbial community.

a Disease incidence (bacterial wilt) in NRPS, PRS, and WRS treatments after pathogen inoculation was shown. All data are presented as mean ± standard error of the mean (SEM) in line graphs (n = 6 biologically independent samples); b Copy numbers of fliC and 16S rRNA genes among different rhizosphere samples. Horizontal bars within boxes represent the median. The tops and bottoms of boxes represent 75th and 25th quartiles, respectively. The upper and lower whiskers represent the range of non-outlier data values. Outliers were plotted as individual points. Different lowercase letters indicated significant differences among respective groups based on two-sided tests for multiple comparisons by Turkey HSD corrections (t-test, adjusted p < 0.05, n = 6 biologically independent samples); c Simple Linear regression analyses performed with the fliC and 16S rRNA genes. The solid lines represent regression lines and transparent areas represent 95% confidence interval. Two-sided t-test was used to test the significance of regression at 5% significance level; d Alpha diversity of the soil bacterial communities across the different treatments. Shannon calculated using the normalized ASV table. Horizontal bars within boxes represent the median. The tops and bottoms of boxes represent 75th and 25th quartiles, respectively. The upper and lower whiskers represent the range of non-outlier data values. Outliers were plotted as individual points. Different lowercase letters indicated significant differences among respective groups based on two-sided tests by Wilcoxon rank-sum test followed by Dunn’s multiple comparison test (adjusted p < 0.05, n = 9 biologically independent samples); e Nonmetric multidimensional scaling (NMDS) analysis based on Bray–Curtis dissimilarity on the taxonomic profile (at the ASV level) of the bacterial communities; f stack bar plot depicting the relative abundances (%) of the major phyla present in the bacterial communities; g The absolute abundance of 470 genera negatively correlated/ uncorrelated with R. solanacearum varied across samples. Absolute abundances were converted by multiplying the 16S rRNA gene qPCR quantification results by the relative abundance of microorganisms. The horizontal coordinates represent the 470 genera, and the vertical coordinates represent the absolute abundance. The dots represent the values of absolute microbial abundance in different samples, and the curves represent the results of fitting the changes in microbial abundance. WRS water with pathogen, PRS prebiotics with pathogen, NPRS non-prebiotics with pathogen, PW prebiotics with water, NPW non-prebiotics with water, WW only water.