Table 2.

Classification, distribution, and relative abundance of 16S rRNA-defined bacterial OTUs recovered from root samples of E. purpurea treated with five different concentrations of organic matter in soil.

	OTU	Phyla	Family or genus	Average percent/group
				T1	T2	T3	T4	T5
T1	0211	Acidobacteria	Group 4	0.151*	0.000	0.002	0.000	0.000
	0777	Acidobacteria	Group 6	0.100*	0.027	0.008	0.000	0.000
	0140	Actinobacteria	Streptomyces	0.945*	0.096	0.141	0.198	0.053
	0470	Actinobacteria	Conexibacter	0.224*	0.023	0.049	0.022	0.000
	0077	Actinobacteria	Aeromicrobium	0.193*	0.117	0.006	0.000	0.024
	0307	Bacteroidetes	Chryseolinea	0.165*	0.109	0.035	0.019	0.013
	0299	Bacteroidetes	Chryseolinea	0.126*	0.059	0.017	0.005	0.040
	0124	Bacteroidetes	Chitinophagaceae	0.308*	0.043	0.018	0.014	0.144
	0094	Bacteroidetes	Flavobacterium	0.668*	0.039	0.165	0.128	0.122
	0500	Bacteroidetes	Filimonas	0.120*	0.000	0.000	0.010	0.008
	0332	Chloroflexi	Ktedonobacter	0.112*	0.084	0.032	0.006	0.011
	0342	Chloroflexi	Heliothrix	0.131*	0.061	0.041	0.044	0.019
	0801	Chloroflexi	Levilinea	0.073*	0.017	0.010	0.007	0.012
	0362	Chloroflexi	Bellilinea	0.115*	0.020	0.027	0.057	0.000
	0478	Firmicutes	Unclassified	0.103*	0.069	0.028	0.000	0.011
	0649	Firmicutes	Aneurinibacillus	0.082*	0.000	0.000	0.006	0.000
	0759	Planctomycetes	Zavarzinella	0.054*	0.000	0.006	0.000	0.028
	0892	Planctomycetes	Thermogutta	0.072*	0.028	0.013	0.005	0.000
	0164	Alphaproteobacteria	Sphingopyxis	0.782*	0.019	0.194	0.021	0.024
	0232	Alphaproteobacteria	Sphingobium	0.178*	0.002	0.028	0.079	0.006
	0904	Alphaproteobacteria	Oceanibaculum	0.088*	0.016	0.006	0.007	0.000
	1040	Verrucomicrobia	Terrimicrobium	0.055*	0.000	0.000	0.000	0.000
	0400	Verrucomicrobia	Spartobacteria	0.123*	0.011	0.003	0.036	0.005
T3	0506	Firmicutes	Bacillus	0.000	0.015	0.091*	0.006	0.006
	0005	Gammaproteobacteria	Enterobacteriaceae	2.679	8.240	10.270*	6.820	3.468
	0184	Gammaproteobacteria	Stenotrophomonas	0.029	0.000	0.080*	0.056	0.025
T5	0259	Bacteroidetes	Flavisolibacter	0.034	0.026	0.004	0.050	0.122*
	0198	Alphaproteobacteria	Asticcacaulis	0.139	0.057	0.016	0.095	0.296*
	0246	Betaproteobacteria	Cupriavidus	0.053	0.058	0.085	0.011	0.469*
	0644	Verrucomicrobia	Subdivision 3	0.017	0.000	0.000	0.000	0.139*

OTUs shown were detected in at least two out of six replicates per treatment condition. Percent organic matter in soil: T1 (67.5%) – T2 (23.2%) – T3 (10.4%) – T4 (5.6%) – T5 (2.5%). A total of 48,197 16 S rRNA gene sequences were analyzed for treatment T1, 26,471 for T2, 64,655 for T3, 18,555 for T4, and 40,933 for T5.

Significance between treatments indicated by *p < 0.05.