Fig. 4

Bacterial indicator phylotypes correlate to naringenin degradation. a Plot of regression coefficients of 86 bacterial OTUs identified by INDVAL in PLS model using naringenin-biodegrading activities as the response variable. Columns with positive values mean that the OTUs are positively correlated to the response variable and vice versa. Columns in red mean Gram-negative OTUs and columns in purple mean Gram-positive. Error bars with 95% confidence intervals that do not cross the horizontal axis mean statistically significant coefficients. b Relative abundances of the 86 OTUs as indicator phylotypes that characterize specific activity groups. OTUs shown in red color are those specialized in the low activity group, shown in green are the ones characterizing medium activity group and shown in blue are those more specifically enriched in high activity group. Neighbor-joining phylogenetic tree of the OTUs is shown on the left and corresponding taxonomy information (by RDP classifier) is shown on the right. IV: indicator value. Samples are arranged along their activity levels as denoted at the bottom. The color intensity of each OTU means its relative abundance in each sample