Fig. 6

Community structure and composition of potential Legionella hosts resembles that of Legionella spp. Next-generation sequencing (NGS) was performed using universal protists primers, designed for the V9 region of the 18S rRNA gene. Raw data were pre-filtered to retain Amoebozoa, Ciliophora (Ciliates), and Percolozoa (Excavata) amplicon sequence variants (ASVs), present at a minimal frequency of 20 or 500 reads across all samples, in a minimum of 2 samples. Water (n = 40) and biofilm (n = 25) were analyzed separately. Spring clusters: Tiberias Hot Springs (n = 20), Haon borehole (n = 4), Fuliya (n = 8), and Tabgha (n = 33). ASVs are represented by the last 5 letters of a letter-number code. For the full-length code and corresponding sequence, see Supplementary Data 2. a Venn diagram presenting ASVs of potential Legionella hosts (minimum 20 reads) in water (right panel) and biofilm (left panel) samples, separated according to spring cluster. b Relative abundance of potential Legionella hosts ASVs, according to spring cluster and collection dates. ASVs at the phylum level (top panel, min 20 reads) and at the ASV level (middle and bottom panels, minimum 20 and 500 reads, respectfully) are presented. Samples are ordered by date, faceted vertically by spring cluster and horizontally by water and biofilm. As numerous ASVs (400) were included in the construction of each barplot, colors are repetitive and are not indicative of specific ASVs. The identity of the most abundant ASVs is presented in the heatmaps (Fig. 6c,d). For Nur station, only biofilm from Sep 2017 was available. c + d Heatmap presenting abundant ASVs of potential Legionella hosts (minimum 500 reads), in c biofilm and d water samples. ASVs were grouped according to Hierarchical clustering and ordered according to sodium concentrations. The heatmap color scale represents high (green to yellow) and low (blue to purple) values. Sodium concentrations and spring clusters are presented to the left of the heatmap