Fig. 1

Effects of chloroplast DNA from Virola officinalis and number of amplification reactions on PCR products from the 16S rRNA gene amplified with primers 799F and U1492R. a Amplification patterns from ‘nested’ and ‘direct’ PCR done on pooled DNA from a 5-OTUs’ mock bacterial community (MBC), with different percentages of amplified/purified V. officinalis cp DNA (see Methods) added to samples prior to the PCR. Agarose and polyacrylamide gels were stained with GelGreen™. ‘L’: size ladder; ‘100’, ‘65’, ‘30’, ‘0’: percentage of cpDNA; ‘C+’: positive control (DNA of a single bacterial isolate); ‘C–’: negative control. b Chloroplast and bacterial 16S rDNA amplification patterns in V. officinalis total leaf-DNA samples from nested PCR; ‘1 to 5’: distinct plant individuals from the same area. c Patterns of nested and direct PCR from the same samples of total DNA extracted from V. officinalis leaves; ‘6 to 9’: distinct plants from same area. d AluI restriction profiles from MBCs amplified with different percentages of cpDNA. ‘L’: size ladder (50 pb); ‘C5’: 5-OTUs’ MBC; ‘C10’: 10-OTUs’ MBC; ‘100’, ‘65’, ‘30’, ‘0’: percentages of cpDNA in the MBCs, prior to PCR, digestion and electrophoresis in 5–11% polyacrylamide gradient gel