Table 5. Properties of group-specific primer pairs and their coverage for phylogenetic and environmental groups.
Specific groupingsa (%) | Environ.b (%) | |||||||||||||
Primer set | Pos.c | Len.d | nifH e | Pr | Cy | III | IA | Fr | Pb | Ep | IV | Soil | Mat | Sea |
ChenBR1/ChenBR2 | 18–698 | 681 | 19 | 35 | 0 | 0 | 7 | 75 | 0 | 0 | 0 | NA | 0 | 0 |
nifH-a1-forA/nifH-a1-rev | 19–482 | 464 | 5 | 12 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | NA | 0 | 0 |
nifH-f1-forA/nifH-f1-rev | 19–482 | 464 | 3 | 0 | 0 | 0 | 0 | 92 | 0 | 0 | 0 | NA | 0 | 0 |
nifHF/nifHI | 25–806 | 782 | 15 | 33 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 100 | 0 | 0 |
primer-3/primer-4 = AQE | 37–453 | 417 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
nifHf1/nifH-269 | 43–341 | 299 | 1 | 0 | 0 | 0 | 0 | 19 | 0 | 0 | 0 | 0 | 0 | 0 |
nifHf1/nifHr | 43–690 | 648 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Olsen1/Olsen2 | 106–494 | 389 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
cyanoF/cyanoR | 108–482 | 375 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
nifH-a1-forB/nifH-a1-rev | 112–482 | 371 | 5 | 11 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 0 |
nifH-a2-forB/nifH-a2-rev | 112–482 | 371 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
nifH-b1-forB/nifH-b1-rev | 112–482 | 371 | 1 | 2 | 0 | 0 | 6 | 0 | 0 | 0 | 0 | 5 | 0 | 0 |
nifH-c1-forB/nifH-c1-rev | 112–482 | 371 | 1 | 1 | 0 | 3 | 1 | 0 | 0 | 4 | 0 | 4 | 0 | 0 |
nifH-f1-forB/nifH-f1-rev | 112–482 | 371 | 20 | 4 | 0 | 2 | 7 | 87 | 0 | 0 | 0 | 6 | 0 | 0 |
nifH-g1-forB/nifH-g1-rev | 112–482 | 371 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 2 | 0 | 0 |
nifHFor/NifHRev | 136–452 | 317 | 5 | 9 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 3 | 0 | 0 |
cylnif-F/cylnif-R | 156–375 | 220 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
NIFH2F/NIFH5R | 231–326 | 96 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 |
FGPH750/FGPD913′ | 759−f | 116 | 0 | 0 | 0 | NA | NA | 0 | NA | NA | 0 | NA | NA | NA |
Data indicate primer binding to specific groupings in the nifH phylogeny. Abbreviations are as follows: Alpha, Beta, and Gamma Proteobacteria (Pr); Cyanobacteria (Cy); Cluster III (III); Cluster IA (IA); Paenibacillus (Pb); Frankia (Fr); Epsilon Proteobacteria Containing Cluster (Ep); paralogous sequences in Cluster IV (IV). In some cases highly degenerate primers bind to multiple positions in the sequence generating coverage values that exceed 100%.
Primer coverage queried against sequences recovered from specific environments (Environ.) as described in methods. Environments include: soils (Soil), microbial mats (Mat), and pelagic marine samples (Sea).
Position of amplicon in nifH is relative to A. vinelandii nifH (Genbank ACCN# M20568).
Length expected for PCR amplicon.
Data indicate primer binding with 0 mismatches to all nifH sequences in the database.
This binding position for the reverse primer sequence lies beyond the stop codon of Frankia sp. (Genbank ACCN# M21132) and cannot be represented using the A. vinelandii numbering system.
NA Data not available as nucleotide information is not available for the target group in the region of primer binding.