Geology and climate influence rhizobiome composition of the phenotypically diverse tropical tree Tabebuia heterophylla

rapid water shedding (S3C Fig). Karst samples, from both humid and dry sites, cluster together phenotypically since they have the shortest leaflet petiole length (S3D Fig), and have the small- est trees (S3E Fig). As explained before, samples from dry karst (site 5) correspond to very high temperatures and cluster separately from other temperatures with the low temperature site being the most dissimilar (S3F Fig). Even though the temperature range differences may seem small, combined with differences in other factors, like precipitation or water availability, can result in considerably different microenvironments that can affect the biology of some plant species. Patterns of taxon abundance helped further elucidate the microbial communities’ differ- ences across sites. Focusing on prevalent OTUs present in at least 40% of the samples and with relative abundances greater than 3%, 26 Phyla were observed among which the most dominant were Proteobacteria, followed by Actinobacteria and Acidobacteria; the only archaeal phylum accounting for >10% of the community was Crenarchaeota (Fig 4A). A total of 13 phyla changed significantly with the mean annual temperature (Fig 4B, S4 Fig). Indeed, sites with lower temperatures had significantly higher amounts of Verrucomicrobia and Acidobacteria, especially in the high elevation volcanic site (S1 Fig) (Fig 4C). The high elevation serpentine site (S3) which had medium temperatures, site resulted with significantly higher amounts of Cyanobacteria, Firmicutes, Nitrospirae, and Bacteroidetes than all other sites (Fig 4B and 4C).

High temperature sites (including both karst sites) had significantly higher amounts of Proteo- bacteria (Fig 4B), SPAM (now called Candidate phylum Rokubacteria [32]) and Chloroflexi, Fig 3. Beta diversity plots. Panel A shows nMDS ordination based on the relative dissimilarities of the 137 samples (Bray Curtis) (stress 0.1232491) representing each parent material and elevation along with microhabitat. The Principal coordinates of panel B, corresponding to the collapsed sample units n = 36, demonstrate that primary clustering is by geology and elevation, mainly separating the Karst samples from the rest of the parent materials as shown also in the nMDS plot. https://doi.org/10.1371/journal.pone.0231083.g003 PLOS ONE Rhizobiota of the tropical tree Tabebuia heterophylla PLOS ONE | https://doi.org/10.1371/journal.pone.0231083 April 7, 2020 8 / 16