Furthermore, it was possible to separate the leaf-derived samples in accordance to the presence of thymol (Figure 6a, b). PCA of the samples from the Alphaproteobacteria showed a separation along the first and second axes of the communities found in the leaves and in the stems (Figure 6c). While the leaf-derived samples belonging to the genotypes LSID003, LSID006 and LSID105 were grouped in accordance to the presence of thymol, those from LSID104 were also correlated with the presence of carvacrol (Figure 6c). Likewise, PCA of the Betaproteobacteria samples showed the tendency to group according

to plant location. Stem-derived samples were separated from leaf-derived samples mainly along the first axis. The Betaproteobacteria community found in the leaves was also associated with the presence of thymol (Figure 6d). With respect to BIX 1294 nmr the Actinobacteria, PCA ordination of the samples did not show any tendency to group, along either the first or second

axes (Figure 6e). In this case, the presence of thymol does not seem to be related to the actinobacterial communities found in the leaves of L. TGF-beta inhibitor sidoides (Figure 6e). Finally, PCA ordination of the fungal communities showed Selleckchem PF477736 a loose grouping in the function of the plant location along the second axis (Figure 6f). Again, the essential oil component, thymol, may have a positive effect on the selection of the leaf-derived fungal communities. Discussion The interaction between plants and microorganisms has already been studied in different essential oil-producing plants, such as vetiver [13, 14, 33] and basil [34]. In

a few cases, the microbial community associated with the plant interferes with the composition of the essential oil [13, 14]. Thus far, there is no evidence that the essential oil produced in the leaves of Lippia sidoides (pepper-rosmarin), which is composed mainly of the two strongly antimicrobial monoterpenes thymol and carvacrol, is biotransformed inside the plant. Additionally, 3-mercaptopyruvate sulfurtransferase no data were available in the literature showing whether the essential oil interferes with the diversity of the microbial communities found inside of the plant and in strict contact with the volatile components of the essential oil. Therefore, we used cultivation-dependent and cultivation-independent methods to analyze microorganisms to increase our understanding of the behavior of the different microbial communities present in the stems and leaves (where the essential oil is found) of L. sidoides. The CFUs were determined following the disinfection of the stems and leaves of four genotypes of L. sidoides. Bacterial colonization of the interior of L. sidoides was expected as it was previously observed in other plants [35, 36]. However, no bacterial cells were recovered from the leaves of three genotypes (LSID003, LSID006 and LSID104), and the number of colonies from the leaves of the remaining genotype was much lower than the CFUs found in the stems.