Table 2.
Total relative abundance and prevalence of the 20 most abundant OTUs (both fruit species considered together) in floral nectar from apple (A) and pear (P) over three sampling days, including start of the flowering period (day 1), peak blooming (day 4), and three days later (day 7)
| OTU | Taxonomic affiliationa | Taxonomic affiliationb | A | B | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Day 1 | Day 4 | Day 7 | Day 1 | Day 4 | Day 7 | |||||||||||
| Phylum | Family | Species | Rel. ab. (%)c | Present in orchard (n = 14) | Rel. ab. (%) | Present in orchard (n = 5) | Rel. ab. (%) | Present in orchard (n = 5) | Rel. ab. (%) | Present in orchard (n = 9) | Rel. ab. (%) | Present in orchard (n = 5) | Rel. ab. (%) | Present in orchard (n = 4) | ||
| OTU1 | Actinobacteria | Brevibacteriaceae | Brevibacterium aurantiacum (100%) | Brevibacterium sp. (100%) (nectar) | 0.6% | 9 | 2.7% | 5 | 0.5% | 5 | 25.9% | 9 | 21.5% | 5 | 37.4% | 4 |
| OTU2 | Proteobacteria | Oxalobacteraceae | Undibacterium oligocarboniphilum (100%) | Burkholderia sp. (95%) (nectar) | 3.7% | 14 | 28.2% | 5 | 15.4% | 5 | 7.6% | 9 | 6.5% | 5 | 10.0% | 4 |
| OTU3 | Firmicutes | Staphylococcaceae | Several Staphylococcus spp. (100%) | Unidentified bacterium (100%) (nectar) and several Staphylococcus spp., including Staphylococcus epidermidis (100%) (honeybee stomach) | 3.5% | 14 | 9.3% | 5 | 5.5% | 5 | 7.2% | 9 | 8.4% | 5 | 7.4% | 4 |
| OTU9 | Bacteroidetes | Tannerellaceae | Parabacteroides johnsonii (95%) | Uncultured bacterium (87%) (bee bread food stores) | 9.0% | 12 | 0.2% | 1 | 0.1% | 1 | 1.4% | 9 | 2.3% | 5 | 0.6% | 4 |
| OTU19 | Bacteroidetes | Tannerellaceae | Parabacteroides sp. (96%) and Parabacteroides chinchillae (96%) | Uncultured bacterium (89%) (bee bread food stores) | 6.9% | 12 | 0.0% | 0 | 0.3% | 2 | 1.3% | 9 | 1.6% | 5 | 0.5% | 4 |
| OTU4 | Actinobacteria | Dermabacteraceae | Several Brachybacterium spp. (100%) | Unidentified bacterium (93%) (nectar) and Janibacter sanguinis (93%) (bee bread food stores) | 0.1% | 12 | 0.4% | 3 | 1.0% | 4 | 4.0% | 9 | 2.7% | 5 | 5.0% | 4 |
| OTU6 | Proteobacteria | Rhizobiaceae | Agrobacterium fabrum (100%) and Agrobacterium tumefaciens (100%) | Rhizobium pusense (100%) (honeybee stomach) and Agrobacterium tumefaciens (100%) (honeybee stomach); Rhizobiaceae sp. (98%) (nectar) | 3.6% | 12 | 1.7% | 4 | 0.5% | 2 | 1.1% | 9 | 1.7% | 5 | 0.9% | 4 |
| OTU10 | Fusobacteria | Fusobacteriaceae | Fusobacterium varium (100%) | Uncultured bacterium (95%) (bee bread food stores) | 4.6% | 12 | 0.2% | 2 | 0.3% | 1 | 0.9% | 9 | 1.1% | 5 | 0.5% | 4 |
| OTU22 | Bacteroidetes | Tannerellaceae | Several Parabacteroides spp. (94%) | Uncultured bacterium (88%) (bee bread food stores) | 4.7% | 11 | 0.2% | 2 | 0.4% | 3 | 0.7% | 9 | 1.1% | 5 | 0.2% | 3 |
| OTU8 | Firmicutes | Streptococcaceae | Several Streptococcus spp. (100%) | Uncultured bacterium (100%) (bee bread food stores) | 1.0% | 14 | 1.7% | 5 | 1.5% | 5 | 2.0% | 9 | 3.0% | 5 | 1.5% | 4 |
| OTU11 | Actinobacteria | Corynebacteriaceae | Corynebacterium accolens (100%) and Corynebacterium macginleyi (100%) | Corynebacterium sp. (99%) (bee bread food stores) | 0.4% | 14 | 4.4% | 5 | 0.8% | 5 | 1.7% | 9 | 2.2% | 5 | 1.6% | 4 |
| OTU12 | Firmicutes | Bacillaceae | Several Bacillus spp. (100%) | Several Bacillus spp., including Bacillus subtilis (100%) (nectar) | 0.3% | 14 | 7.2% | 4 | 1.8% | 3 | 1.4% | 9 | 1.1% | 5 | 1.7% | 4 |
| OTU7 | Proteobacteria | Moraxellaceae | Acinetobacter lwoffii (100%) | Acinetobacter sp. (99%) (nectar) | 1.2% | 14 | 2.1% | 5 | 3.1% | 5 | 1.6% | 9 | 1.1% | 5 | 1.2% | 4 |
| OTU13 | Bacteroidetes | Bacteroidaceae | Several Bacteroides spp. (94%) | Uncultured bacterium (86%) (bee bread food stores) | 3.0% | 11 | 0.0% | 1 | 0.5% | 2 | 0.7% | 9 | 0.9% | 5 | 0.4% | 4 |
| OTU5 | Actinobacteria | Micrococcaceae | Several Nesterenkonia spp. (100%). | Unidentified bacterium (98%) (nectar) and Nesterenkonia aethiopica (98%) (honeybee stomach) | 0.1% | 3 | 1.3% | 3 | 0.3% | 3 | 2.0% | 9 | 1.7% | 5 | 2.6% | 4 |
| OTU29 | Proteobacteria | Moraxellaceae | Several Acinetobacter spp. (99%) | Acinetobacter schindleri (99%) (insect) | 1.1% | 14 | 2.0% | 4 | 0.7% | 4 | 1.1% | 9 | 1.2% | 5 | 1.1% | 4 |
| OTU17 | Proteobacteria | Morganellaceae | Photorhabdus asymbiotica (94%) | Aeromonas veronii (91%) (alimentary tract midgut honeybee) | 2.4% | 10 | 0.5% | 2 | 0.0% | 0 | 0.5% | 8 | 0.7% | 5 | 0.4% | 4 |
| OTU36 | Proteobacteria | Pseudomonadaceae | Several Pseudomonas spp. (100%) | Unidentified bacterium (100%) (nectar) | 2.4% | 14 | 0.1% | 2 | 1.3% | 5 | 0.5% | 9 | 0.6% | 5 | 0.5% | 4 |
| OTU367 | Proteobacteria | Enterobacteriaceae | Several Enterobacteriaceae spp. (99%) | Several Enterobacteriaceae, including Erwinia sp. (99%) (nectar) | 1.3% | 13 | 0.6% | 2 | 1.1% | 5 | 1.0% | 9 | 1.2% | 5 | 0.9% | 4 |
| OTU15 | Firmicutes | Bacillaceae | Several Bacillus spp. (100%). | Several Bacillus spp. (100%) (nectar) | 1.7% | 13 | 0.5% | 3 | 0.3% | 2 | 0.8% | 9 | 1.4% | 5 | 0.3% | 4 |
Nearest neighbor based on a BLAST search in GenBank against type strains. Percentage of sequence identity (on a total of 250 bp) is reported between brackets. Taxonomic assignment at phylum and family level was performed manually based on assigned species.
Nearest neighbor based on a BLAST search in GenBank against sequence entries related to the nectar environment (search was limited to sequences associated with the keyword "nectar"). Percentage of sequence identity (on a total of 250 bp) is reported between brackets.
Total relative abundance, calculated based on the total sum of sequences obtained for the OTU divided by the total number of sequences obtained at each sampling point for the apple or pear dataset x 100 (%).