Table 3. Taxonomic classification and average relative abundance (% total community) of core symbiont OTUs (present in all 44 H. heliophila samples).

OTU	Phylum	Lowest Taxonomic Classification	Avg. Relative Abundance
1	Proteobacteria	Novosphingobium resinovorum (α-proteo.)	17.44
2	Proteobacteria	Order Kiloniellales (α-proteo.)	8.68
3	Proteobacteria	Thiorhodospira sp. (γ-proteo.)	6.44
4	Proteobacteria	Family Rhodospirillaceae (α-proteo.)	5.91
5	Planctomycetes	Family Pirellulaceae	6.02
6	Actinobacteria	Order Actinomycetales	3.10
7	Proteobacteria	Shewanella amazonensis (γ-proteo.)	3.25
9	Cyanobacteria	Synechococcus sp.	2.74
10	Verrucomicrobia	Persicirhabdus sp.	1.55
11	Bacteroidetes	Family Flavobacteriaceae	1.61
13	Proteobacteria	Bartonella bacilliformis (α-proteo.)	1.24
14	Spirochaetes	Leptonema sp.	1.15
15	Cyanobacteria	Synechococcus sp.	1.06
16	Proteobacteria	Bdellovibrio sp. (δ-proteo.)	1.05
17	Planctomycetes	Family Pirellulaceae	0.75
22	Proteobacteria	Family Methylophilaceae (β-proteo.)	0.56
31	Bacteroidetes	Family Flavobacteriaceae	0.38
32	Bacteroidetes	Flavobacterium sp.	0.30