Fig. 4

The taxonomic composition of OTUs from four groups. a: The number of shared and unique OTUs in different groups; b: Relative microbiota abundance at the phyla level; c: Relative microbiota abundance at the genus level. The y-axis shows the sample name, and the x-axis is the proportion of the species in the sample. The pillar of different colors represents different species, and the length of the pillar represents the proportion of the species. OTU: operational taxonomic unit. Group 1 represents the sun-dried unfermented tobacco leaves; group 2 represents leaves fermented at 45 °C for 2 weeks; group 3 represents leaves fermented at 45 °C for 4 weeks; and group 4 represents leaves fermented at 45 °C for 6 weeks