SUPPLEMENTAL TABLES
Table S1. Effect of all treatments on final gravimetric soil moisture. F-statistic and p-values provided; significant p-values (p < 0.05) are bolded. Factor F, p
Precipitation 7.981,27, 0.008
Microbial treatment 0.542,27, 0.591
Life-stage 3.511,27, 0.072
Precip.* Soil.Treat. 0.292,27, 0.753
Precip.* Life-stage 0.011,27, 0.919
Mic.Treat.*Life-stage 0.172,27, 0.844
Precip.*Mic.Treat.*Life-stage 0.052,27, 0.954
Table S2. Full-model ANOVA results for the effect of precipitation and all microbial treatments (bulk, autoclaved, and rhizosphere) on germinant responses. Chi- square, F-statistic and p-values provided; significant p-values (p < 0.05) are bolded. Germination rate Germinant Germinant total Germinant final Germinant final Days to first (Number of survival biomass (g) Germinant bacterial Germinant final Factor bacterial Inverse germination seeds that (given (given root:shoot community bacterial richness Simpson germinated/ germination) germination) composition pot) F, p χ2, p χ2, p F, p F, p R2 p F, p F, p Precipitation 3.541,50, 0.066 4.30, 0.038 0.06, 0.803 0.841,39, 0.365 8.341,37, 0.006 0.06 <0.001 1.591,14, 0.228 0.031,17, 0.864 Microbial treatment 4.632,51, 0.014 4.79, 0.091 7.06, 0.029 3.982,39, 0.027 0.942,38, 0.398 0.44 <0.001 355.682,15, <0.001 16.472,17, <0.001 Precip.* Microbial 0.682,51, 0.513 1.89, 0.388 2.36, 0.307 10.012,39, <0.001 2.592, 38, 0.088 0.05 0.006 0.702,15, 0.514 0.242,17, 0.789 treatment
Ulbrich et al. SUPPLEMENTAL Page 1/15
Table S3. Full-model ANOVA results for the effect of precipitation and all microbial treatments (bulk, autoclaved, and rhizosphere) on seedling responses. Chi- square, F-statistic and p-values provided; significant p-values (p < 0.05) are bolded. Seedling final Seedling final Seedling specific Seedling Seedling final Seedling total Seedling Seedling bacterial bacterial Factor root length rhizosheath bacterial biomass (g) root:shoot survival community Inverse (cm g dry root-1) weight (g) richness composition Simpson F, p F, p χ2, p F, p F, p R2 p F, p F, p Precipitation 13.421,80, <0.001 1.441,74, 0.234 NA 5.571,18, 0.030 0.101,21, 0.753 0.06 0.011 5.001,18, 0.038 1.401,18, 0.253
Microbial treatment 4.892,80, 0.010 0.312,74, 0.738 15916,<0.001 0.772,17, 0.478 2.592,21, 0.098 0.59 0.004 67.982,18, <0.001 3.902,18, 0.039
Precip.* Microbial 3.342,80, 0.041 0.492,74, 0.617 NA 4.072, 17, 0.036 0.092,21, 0.912 0.07 0.060 2.342,18, 0.124 2.862,18, 0.084 treatment
Ulbrich et al. SUPPLEMENTAL Page 2/15
Table S4. Full model results for all response variables measured on both life-stages; split by microbial presence (bulk vs. autoclaved) and inocula association history (rhizosphere vs. bulk). Chi-square, F-statistic and p-values provided; significant p-values (p < 0.05) are bolded. Survival just Final Bacterial Final Bacterial Bacterial Community Biomass Root:shoot in drought Richness Inv. Simpson Composition Factor χ2, p F, p F, p F, p F, p R2 P Precipitation NA 0.351,76 0.,557 6.441,113, <0.001 3.471,20, 0.077 0.101,23, 0.759 0.06 <0.001 Microbial Presence 5.06, 0.024 7.801,76, 0.007 0.462,113, 0.083 685.071,20, <0.001 12.631,23, 0.002 0.48 <0.001 Life-stage 0.68, 0.408 1.66 , 0.202 23.46 , <0.001 13.85 , 0.001 9.52 , 0.005 0.04 0.006 Microbial 1,78 1,113 1,20 1,23 Precip.* Mic.Pres. NA 1.011,78, 0.302 0.632,113, 0.014 1.301,20, 0.268 0.101,23, 0.757 0.03 0.021 Presence Precip.* Life-stage NA 10.191,76, 0.002 2.251,113, 0.007 0.111,20, 0.741 0.201,23, 0.656 0.02 0.148 Mic.Pres.*Life-stage 1.48, 0.223 0.131,76, 0.721 0.472,113, 0.043 0.011,20, 0.938 1.841,23, 0.189 0.05 0.004 Precip.* Mic.Pres.*Life-stage NA 12.811,78, 0.001 2.362,113, <0.001 0.011,20, 0.939 1.491,23, 0.234 0.02 0.174
Precipitation NA 7.191,87, 0.009 2.741,84, 0.102 3.331,24, 0.080 0.931,24, 0.345 0.021 0.001 Microbial Inocula 0.47, 0.494 0.011,85, 0.921 0.821,84, 0.368 4.061,24, 0.055 6.411,24, 0.018 0.08 0.021 Microbial Life-stage 0.34, 0.558 3.831,4, 0.116 16.491,84, <0.001 1.761,24, 0.197 0.301,24, 0.592 0.02 0.503 Association Precip.* Mic.Inoc. NA 0.271,84, 0.606 0.081,84, 0.777 1.191,24, 0.286 2.101,24, 0.160 0.03 0.245 History Precip.* Life-stage NA 0.251,87, 0.620 0.311,84, 0.578 2.451,24, 0.131 0.451,24, 0.510 0.02 0.343 Mic.Inoc.*Life-stage 0.09, 0.759 0.871,85, 0.354 0.031,84, 0.870 5.541,24, 0.027 3.011,24, 0.092 0.11 0.006
Precip.* Mic.Inoc.*Life-stage NA 0.001,84, 0.996 0.381,84, 0.540 1.631,24, 0.213 2.541,24, 0.124 0.05 0.062
Ulbrich et al. SUPPLEMENTAL Page 3/15
Table S5. Final bacterial community analyses for microbial presence treatments (autoclaved and bulk microbial treatments only). F-statistic and p-values provided; significant p-values (p < 0.05) are bolded. Bacterial
Bacterial Inverse community composition Factor Bacterial richness Simpson (Weighted Unifrac)
F, p F, p R2 p
Precipitation 0.271,8, 0.617 0.011,11, 0.934 0.11 0.007 Germinant Microbial presence 175.641,8, <0.001 1.731,11, 0.216 0.40 0.007
Precip.* Mic.Presence 0.0021,8, 0.970 0.291,11, 0.598 0.05 0.020
Precipitation 0.681,9, 0.432 2.281,9, 0.165 0.06 0.013
Seedling Microbial Presence 210.611,9, <0.001 25.111,9, <0.001 0.62 0.027
Precip.* Mic.Presence 0.071,9, 0.799 3.181,9, 0.108 0.06 0.023
Table S6. Soil properties for initial inocula (autoclaved bulk, live bulk, live rhizosphere) and final seedling-associated soils. Microbial biomass carbon and dissolved organic carbon were only assessed on the seedling ambient-exposed soils (n = 5 per microbial treatment). F-statistic and p-values provided; significant p-values (p < 0.05) are bolded. Final soil Final soil dissolved Final microbial Factor Initial nitrate Initial ammonium Final soil nitrate ammonium organic carbon biomass carbon F, p F, p F, p F, p F, p F, p
Precipitation NA NA 15.221,17, 0.001 5.361,20, 0.031 NA NA Microbial treatment 0.792,11, 0.477 62.792,11, <0.001 9.122,17, 0.002 16.552,20, <0.001 2.6072,10, 0.123 0.912,10, 0.434 Precip.* Microbial NA NA 4.632,17, 0.025 3.432,20, 0.052 NA NA treatment
Ulbrich et al. SUPPLEMENTAL Page 4/15
Table S7. SIMPER results for bacterial OTUS that differ between the seedling-associated live microbial inocula (rhizosphere and bulk) in drought versus ambient conditions with Weighted Unifrac distance metric. OTUs with significantly greater average percent relative abundance in the drought than ambient soils are presented (p < 0.05). Percent dissimilarity explained refers to the amount of community dissimilarity between the ambient- and drought-exposed bacterial communities that a particular OTU explains. Rows organized by taxonomy and unadjusted p-value presented.
Percent Avg. % Avg. % dissimilarity rel.abund. rel.abund. Unadjusted OTU explained under drought under ambient Phylum Class Order Family Genus P-value
OTU6729 3.75E-05 0.75 0 Acidobacteria Acidobacteria Subgroup_4 UNKONWN Blastocatella 0.023
OTU1520 0.000125 2.5 0 Actinobacteria Acidimicrobiia Acidimicrobiales UNKNOWN UNKNOWN 0.025
OTU851 0.000356 9.5 3.125 Actinobacteria Acidimicrobiia Acidimicrobiales UNKNOWN UNKNOWN 0.012
OTU13605 0.000109 2.375 0.25 Actinobacteria Actinobacteria Corynebacteriales Mycobacteriaceae UNKNOWN 0.01
OTU1903 0.000303 7.5 2.25 Actinobacteria Actinobacteria Corynebacteriales Nocardiaceae Smaragdicoccus 0.023
OTU494 0.000109 2.375 0.375 Actinobacteria Actinobacteria Frankiales Acidothermaceae Acidothermus 0.012
OTU272 0.000264 6.75 2.125 Actinobacteria Actinobacteria Frankiales Frankiaceae UNKNOWN 0.018
OTU6546 0.000481 10.875 1.25 Actinobacteria Actinobacteria Frankiales UNKNOWN UNKNOWN 0.002
OTU3122 0.000548 15.375 5.25 Actinobacteria Actinobacteria Frankiales UNKNOWN UNKNOWN 0.013
OTU13146 0.000306 9.75 4.25 Actinobacteria Actinobacteria Kineosporiales Kineosporiaceae UNKNOWN 0.018
OTU768 0.000433 11.625 3.625 Actinobacteria Actinobacteria Propionibacteriales Nocardioidaceae Aeromicrobium 0.007
OTU80 0.000853 36.375 23.375 Actinobacteria Actinobacteria Pseudonocardiales Pseudonocardiaceae Pseudonocardia 0.048
OTU810 0.00035 10.125 3.625 Actinobacteria Actinobacteria Streptomycetales Streptomycetaceae Streptomyces 0.009
OTU478 0.000356 10 4.375 Actinobacteria Thermoleophilia Gaiellales Gaiellaceae Gaiella 0.035
OTU6042 9.38E-05 1.875 0 Actinobacteria Thermoleophilia Solirubrobacterales 0319-6M6 UNKNOWN 0.005
OTU1155 0.000767 20.875 5.625 Actinobacteria Thermoleophilia Solirubrobacterales 0319-6M6 UNKNOWN 0.002
OTU294 0.001058 32.875 15.75 Actinobacteria Thermoleophilia Solirubrobacterales 288-2 UNKNOWN 0.033
OTU2691 0.000177 4.125 1.375 Actinobacteria Thermoleophilia Solirubrobacterales 480-2 UNKNOWN 0.036
Ulbrich et al. SUPPLEMENTAL Page 5/15
OTU670 0.000225 5.375 1.125 Actinobacteria Thermoleophilia Solirubrobacterales Elev-16S-1332 UNKNOWN 0.008
OTU27076 0.000103 2.25 0.625 Actinobacteria Thermoleophilia Solirubrobacterales Patulibacteraceae Patulibacter 0.045
OTU2132 0.000334 7.625 1.125 Actinobacteria Thermoleophilia Solirubrobacterales Solirubrobacteraceae Solirubrobacter 0.009
OTU2202 0.000167 4.25 1.25 Actinobacteria Thermoleophilia Solirubrobacterales UNKNOWN UNKNOWN 0.024
OTU20834 0.000263 5.75 0.625 Actinobacteria Thermoleophilia Solirubrobacterales UNKNOWN UNKNOWN 0.004
OTU1671 0.000592 13.375 1.625 Actinobacteria Thermoleophilia Solirubrobacterales UNKNOWN UNKNOWN 0.004
OTU6183 8.75E-05 1.75 0 Actinobacteria Thermoleophilia UNKNOWN UNKNOWN UNKNOWN 0.03
OTU1950 8.75E-05 2.5 1.125 Actinobacteria UNKNOWN UNKNOWN UNKNOWN UNKNOWN 0.032
OTU625 0.000166 3.375 0.375 Bacteroidetes Sphingobacteriia Sphingobacteriales Chitinophagaceae Flavisolibacter 0.024
OTU290 0.000178 3.75 0.5 Bacteroidetes Sphingobacteriia Sphingobacteriales Chitinophagaceae Flavitalea 0.038
OTU5580 0.000119 2.375 0 Cyanobacteria ML635J-21 UNKNOWN UNKNOWN UNKNOWN 0.021
OTU5011 0.000188 3.75 0 Cyanobacteria UNKNOWN UNKNOWN UNKNOWN UNKNOWN 0.028
OTU13636 0.000547 11.875 1.25 Firmicutes Bacilli Bacillales Alicyclobacillaceae Tumebacillus 0.005
OTU1519 9.53E-05 2 0.25 Firmicutes Bacilli Bacillales Paenibacillaceae Cohnella 0.005
OTU15601 0.000122 2.875 0.625 Gemmatimonadetes Gemmatimonadetes Gemmatimonadales Gemmatimonadaceae Gemmatimonas 0.024
OTU3603 0.000488 11.25 3.375 Gemmatimonadetes Gemmatimonadetes Gemmatimonadales Gemmatimonadaceae Gemmatimonas 0.032
OTU87 0.000684 19.75 7.75 Gemmatimonadetes Gemmatimonadetes Gemmatimonadales Gemmatimonadaceae Gemmatimonas 0.024
OTU2582 0.000139 3 0.375 Gemmatimonadetes Gemmatimonadetes Gemmatimonadales Gemmatimonadaceae UNKNOWN 0.018
OTU680 0.000216 4.5 0.25 Proteobacteria Alphaproteobacteria Caulobacterales Caulobacteraceae Brevundimonas 0.011
OTU1 0.003589 207.5 145.625 Proteobacteria Alphaproteobacteria Rhizobiales Bradyrhizobiaceae Bradyrhizobium 0.028
OTU986 0.000194 4.875 1.25 Proteobacteria Alphaproteobacteria Rhodospirillales DA111 UNKNOWN 0.008
OTU4584 0.000125 2.5 0 Proteobacteria Alphaproteobacteria Sphingomonadales Sphingomonadaceae Sphingomonas 0.006
OTU17941 0.000269 5.75 0.5 Proteobacteria Alphaproteobacteria Sphingomonadales Sphingomonadaceae Sphingomonas 0.009
OTU8 0.011164 342.125 122 Proteobacteria Alphaproteobacteria Sphingomonadales Sphingomonadaceae Sphingomonas 0.002
Ulbrich et al. SUPPLEMENTAL Page 6/15
OTU14988 0.000511 12.375 2.625 Proteobacteria Alphaproteobacteria Sphingomonadales UNKNOWN UNKNOWN 0.007
OTU5833 0.006244 208.5 101.5 Proteobacteria Betaproteobacteria Burkholderiales Burkholderiaceae Cupriavidus 0.014
OTU13937 0.000883 30.875 18.25 Proteobacteria Betaproteobacteria Burkholderiales Comamonadaceae UNKNOWN 0.042
OTU4921 0.000117 2.375 0.5 Proteobacteria Betaproteobacteria UNKNOWN UNKNOWN UNKNOWN 0.046
Table S8. SIMPER results for bacterial OTUS that differ between the germinant-associated live microbial inocula (rhizosphere and bulk) in drought versus ambient conditions with Weighted Unifrac distance metric. OTUs with significantly greater average percent relative abundance in the drought than ambient soils are presented (p < 0.05). Percent dissimilarity explained refers to the amount of community dissimilarity between the ambient- and drought-exposed bacterial communities that a particular OTU explains. Rows organized by taxonomy and unadjusted p-value presented.
Avg. % Avg. % Percent rel.abund. rel.abund. Unadjusted dissimilarity under under OTU explained drought ambient Phylum Class Order Family Genus P-value
OTU637 0.0004 10.75 4 Acidobacteria Acidobacteria Subgroup_3 UNKNOWN Bryobacter 0.04
OTU15625 0.0001 2 0.375 Acidobacteria Acidobacteria Subgroup_6 UNKNOWN UNKNOWN 0.047
OTU462 0.0003 7 1.75 Actinobacteria Acidimicrobiia Acidimicrobiales Acidimicrobiaceae CL500-29_marine_group 0.01
OTU1439 0.0001 1.25 0.125 Actinobacteria Acidimicrobiia Acidimicrobiales UNKNOWN UNKNOWN 0.048
OTU851 0.0004 8.875 2.625 Actinobacteria Acidimicrobiia Acidimicrobiales UNKNOWN UNKNOWN 0.048
OTU27784 0.0001 2.375 0.25 Actinobacteria Actinobacteria Frankiales Geodermatophilaceae Geodermatophilus 0.022
OTU7549 0.0002 3.5 0.25 Actinobacteria Actinobacteria Frankiales UNKNOWN UNKNOWN 0.024
OTU6546 0.0003 6.375 0.875 Actinobacteria Actinobacteria Frankiales UNKNOWN UNKNOWN 0.009
OTU10 0.0015 61.375 33.25 Actinobacteria Actinobacteria Micrococcales Micrococcaceae Arthrobacter 0.008
OTU2026 0.0001 1.875 0.125 Actinobacteria Actinobacteria Propionibacteriales Nocardioidaceae Nocardioides 0.033
OTU24762 0.0002 4.75 0.25 Actinobacteria Actinobacteria Propionibacteriales Nocardioidaceae Nocardioides 0.032
Ulbrich et al. SUPPLEMENTAL Page 7/15
OTU6394 0.0004 12.75 5 Actinobacteria Actinobacteria Propionibacteriales Nocardioidaceae UNKNOWN 0.018
OTU478 0.0005 10.625 2.625 Actinobacteria Thermoleophilia Gaiellales Gaiellaceae Gaiella 0.045
OTU745 0.0001 2.5 0.25 Actinobacteria Thermoleophilia Gaiellales UNKNOWN UNKNOWN 0.04
OTU18149 0.0002 5 1.375 Actinobacteria Thermoleophilia Gaiellales UNKNOWN UNKNOWN 0.046
OTU55 0.0006 18.875 6.375 Actinobacteria Thermoleophilia Gaiellales UNKNOWN UNKNOWN 0.011
OTU1155 0.0009 19.375 2.125 Actinobacteria Thermoleophilia Solirubrobacterales 0319-6M6 UNKNOWN 0.001
OTU294 0.0011 33.125 15.125 Actinobacteria Thermoleophilia Solirubrobacterales 288-2 UNKNOWN 0.011
OTU27076 0.0002 4.125 0.875 Actinobacteria Thermoleophilia Solirubrobacterales Patulibacteraceae Patulibacter 0.048
OTU16047 0.0002 3.75 0.25 Actinobacteria Thermoleophilia Solirubrobacterales Solirubrobacteraceae Solirubrobacter 0.004
OTU1710 0.0004 11.375 5.125 Actinobacteria Thermoleophilia Solirubrobacterales Solirubrobacteraceae UNKNOWN 0.025
OTU1308 0.0001 3.25 0.75 Actinobacteria Thermoleophilia Solirubrobacterales YNPFFP1 UNKNOWN 0.026
OTU2357 0.0003 6.375 1.125 Actinobacteria Thermoleophilia Solirubrobacterales UNKNOWN UNKNOWN 0.042
OTU1671 0.0005 10.5 1 Actinobacteria Thermoleophilia Solirubrobacterales UNKNOWN UNKNOWN 0.003
OTU719 0.0008 17 2.625 Bacteroidetes Sphingobacteriia Sphingobacteriales Chitinophagaceae UNKNOWN 0.014
OTU100 0.0008 29.375 14.5 Bacteroidetes Sphingobacteriia Sphingobacteriales Chitinophagaceae UNKNOWN 0.026
OTU2777 0.0001 1.375 0.25 Chloroflexi Ktedonobacteria C0119 UNKNOWN UNKNOWN 0.024
OTU20260 0.0001 2.5 0.375 Chloroflexi Ktedonobacteria C0119 UNKNOWN UNKNOWN 0.047
OTU19384 0.0001 1.625 0.25 Chloroflexi TK10 UNKNOWN UNKNOWN UNKNOWN 0.039
OTU1963 0.0001 1.25 0 Chloroflexi UNKNOWN UNKNOWN UNKNOWN UNKNOWN 0.021
OTU1964 0.0005 10.375 0 Firmicutes Bacilli Bacillales Alicyclobacillaceae Tumebacillus 0.03
OTU520 0.0022 52.625 8.125 Firmicutes Bacilli Bacillales Alicyclobacillaceae Tumebacillus 0.002
OTU2208 0.0001 1.875 0.125 Firmicutes Bacilli Bacillales Bacillaceae Bacillus 0.021
OTU4544 0.0003 7.625 2.625 Firmicutes Bacilli Bacillales Bacillaceae Bacillus 0.033
OTU824 0.0002 3.75 0.5 Firmicutes Bacilli Bacillales Paenibacillaceae Paenibacillus 0.002
Ulbrich et al. SUPPLEMENTAL Page 8/15
Clostridium_sensu_stricto_1 OTU1206 0.0002 3.5 0.125 Firmicutes Clostridia Clostridiales Clostridiaceae_1 3 0.01
OTU874 0.0001 2.875 1 Gemmatimonadetes Gemmatimonadetes Gemmatimonadales Gemmatimonadaceae Gemmatimonas 0.013
OTU68 0.0007 29 16.5 Gemmatimonadetes Gemmatimonadetes Gemmatimonadales Gemmatimonadaceae UNKNOWN 0.028
OTU20587 0.0001 2.375 0.625 Proteobacteria Alphaproteobacteria Rhizobiales UNKNOWN UNKNOWN 0.038
OTU17512 0.0001 1.875 0 Proteobacteria Alphaproteobacteria Sphingomonadales Sphingomonadaceae Sphingomonas 0.03
OTU14988 0.0003 8.125 1.25 Proteobacteria Alphaproteobacteria Sphingomonadales UNKNOWN UNKNOWN 0.001
OTU5833 0.0037 145.375 103.375 Proteobacteria Betaproteobacteria Burkholderiales Burkholderiaceae Cupriavidus 0.029
OTU74 0.0020 59 28.5 Proteobacteria Betaproteobacteria Burkholderiales Oxalobacteraceae UNKNOWN 0.036
OTU15951 0.0008 18.25 5.875 Proteobacteria Gammaproteobacteria Pseudomonadales Pseudomonadaceae Pseudomonas 0.049
OTU4 0.0650 1714.63 575.5 Proteobacteria Gammaproteobacteria Pseudomonadales Pseudomonadaceae Pseudomonas 0.01
OTU1527 0.0002 5.375 1.125 Verrucomicrobia Spartobacteria Chthoniobacterales DA101_soil_group UNKNOWN 0.025
OTU7469 0.0002 3.25 0.25 UNKNOWN UNKNOWN UNKNOWN UNKNOWN UNKNOWN 0.003
Ulbrich et al. SUPPLEMENTAL Page 9/15
SUPPLEMENTAL FIGURES
Figure S1. Effect of precipitation and microbial treatment on gravimetric moisture content. Values were averaged from the germinant and seedling soils. Error bars represent ±1 standard error from the mean, numbers indicate replicates for each treatment. Horizontal bars and asterisks represent significant pairwise differences, * p < 0.05.
Ulbrich et al. SUPPLEMENTAL Page 10/15
Figure S2. Soil ammonium and nitrate differences among initial microbial treatments prior to experiment (A, D) and the effect of precipitation and microbial treatment on seedling- (B, E), and germinant-associated (C, F) soils. Error bars represent ±1 standard error from the mean and numbers indicate replicates analyzed for each treatment. Horizontal bars and asterisks represent significant pairwise differences, * p < 0.05, ** p < 0.01, *** p < 0.001.
Ulbrich et al. SUPPLEMENTAL Page 11/15
Figure S3. Effect of precipitation and microbial treatment on switchgrass seedling responses: A) root:shoot ratios given survival, and C) rhizosheath soil mass. Error bars represent ±1 standard error from the mean and numbers indicate replicates analyzed for each treatment. Horizontal bars and asterisks represent significant pairwise differences, * p < 0.05, ** p < 0.01, *** p < 0.001.
Figure S4. Effect of precipitation and microbial treatment on switchgrass germinant responses: A) root:shoot ratios given germination, and C) total biomass given germination. Error bars represent ±1 standard error from the mean and numbers indicate replicates analyzed for each treatment. Horizontal bars and asterisks represent significant pairwise differences, * p < 0.05, ** p < 0.01, *** p < 0.001.
Ulbrich et al. SUPPLEMENTAL Page 12/15
Figure S5. Differences in A) dissolved organic carbon (µg C per g dry soil) and B) microbial biomass carbon (µg C per g dry soil) among microbial treatments for ambient-exposed, seedling-associated soils only. Error bars represent ±1 standard error from the mean and numbers indicate replicates analyzed for each treatment. Horizontal bars and asterisks represent significant pairwise differences, * p < 0.05, ** p < 0.01, *** p < 0.001.
Ulbrich et al. SUPPLEMENTAL Page 13/15
Figure S6. Weighted Unifrac NMDS representing differences between initial soil inocula (black) and final bacterial community composition driven by precipitation (drought – red or ambient – blue) and microbial treatment (bulk soil – circle, rhizosphere soil – triangle, autoclaved soil - diamond) for switchgrass A) seedling- and B) germinant-associated bacterial communities. Pairwise Weighted Unifrac distances between final seedling- (C) and germinant-associated (D) bacterial communities in bulk (circles), rhizosphere (triangles), and autoclaved soil (diamond) compared to the initial soils after exposure to ambient (blue) and drought (red) precipitation treatments. Each point represents the dissimilarity from each rhizosphere or soil block (n = 1 sample) to the initial soil from the same block at the start of the experiment. Bars represent ±1 standard error from the mean of each treatment # p < 0.10, * p < 0.05, ** p < 0.01, *** p < 0.001.
Ulbrich et al. SUPPLEMENTAL Page 14/15
Figure S7. Relative abundance of bacterial phyla from A) initial live soil inocula and final B) seedling- and C) germinant- associated soils across all microbial and precipitation treatments.
Ulbrich et al. SUPPLEMENTAL Page 15/15