Table 1. Expressed genes encoding putative lignocellulolytic and chitinolytic fungal enzymes found in ambient and simulated increased nitrogen litter samples.
| Enzyme (EC number) | Putative enzyme function | Total number of transcribed gene types (ambient, nitrogen plot) | Detected fungal phyla# |
| Ligninolytic enzymes and related | |||
| Manganese peroxidase (EC 1.11.1.13), Class II of the non-animal heme peroxidase superfamily | Extracellular lignin oxidation and breakdown via Mn3+ | 4 (1, 3) | B |
| Laccase (EC 1.10.3.2) | Extracelluar oxidation of phenolics and lignin | 9 (8, 6) | A, B |
| Cellobiose dehydrogenase (EC 1.1.99.18) | Extracellular; putative lignin oxidation via Fenton reaction (generation of hydroxyl-radicals) | 4 (2, 3) | B |
| Oxalate decarboxylase (EC 4.1.1.2) | Oxalate breakdown | 17 (6, 11) | A, B |
| Enzymes oxidizing aromatics | |||
| Heme-thiolate peroxidases; i.e. aromatic peroxygenase (EC 1.11.2.-), chloroperoxidase (EC 1.11.1.10) | Extracellular oxygenations (O-dealkylation, hydroxylation, epoxidation, sulfoxidation, N-oxidation, etc.); unspecific halogenation | 11 (9, 3) | A, B |
| Tyrosinase (EC 1.14.18.1) | Intracellular and cell-wall-associated oxidation of phenols, pigmentation | 5 (3, 2) | A, B |
| Intradiol ring cleavage dioxygenase, putative catechol 1,2-dioxygenase (EC 1.13.11.1) or hydroxyquinol 1,2-dioxygenase (EC 1.13.11.37) | Intracellular cleavage of aromatic rings | 7 (5, 3) | A |
| Cellulolytic, hemicellulolytic and related enzymes (all extracellular) § | |||
| GH3: putative β-glucosidase (EC 3.2.1.21) or xylan 1,4-β-xylosidase (EC 3.2.1.37) | Cellulose and xylan backbone degradation | 25 (22, 4) | A |
| GH5: putative mannan endo-1,4-β-mannosidase (EC 3.2.1.78) or endoglucanase (EC 3.2.1.4) | Mannan & cellulose degradation | 9 (4, 5) | A, B |
| GH6: cellulose 1,4-β-cellobiosidase, i.e. cellobiohydrolase II (EC 3.2.1.91) | Cellulose degradation | 3 (2, 1) | A, B |
| GH7: cellobiohydrolase I (EC 3.2.1.-) or endoglucanase (EC 3.2.1.4) | Cellulose degradation | 11 (5, 6) | A, B |
| GH10: endo-1,4-β-xylanase (EC 3.2.1.8) | Xylan backbone degradation | 3 (2, 1) | A, B |
| GH11: endo-1,4-β-xylanase (EC 3.2.1.8) | Xylan backbone degradation | 14 (10, 8) | A, B |
| GH31: α-glucosidase (EC 3.2.1.20) | Starch degradation | 10 (4, 6) | A |
| GH45: endoglucanase (EC 3.2.1.4) | Cellulose degradation | 11 (7, 7) | A, Z |
| GH51: α-L-arabinofuranosidase (EC 3.2.1.55) | Xylan sidechain (arabinan) degradation | 9 (5, 4) | B |
| GH67: α-glucuronidase (EC 3.2.1.139) or xylan α-1,2-glucuronosidase (EC 3.2.1.131) | Xylan sidechain (glucuronic acid) degradation | 8 (5, 3) | A |
| GH74: endoglucanase (EC 3.2.1.4) or putative xyloglucan-specific endo-β-1,4-glucanase (EC 3.2.1.151) | Cellulose degradation | 4 (2, 2) | A, B |
| GH92: putative α-1,2-mannosidase (EC 3.2.1.-) | Mannan sidechain degradation | 9 (2, 8) | A |
| CE1: acetylxylan esterase (EC 3.1.1.72) | Xylan sidechain degradation | 5 (2, 3) | A |
| Cellobiose dehydrogenase (EC 1.1.99.18) | Cellobiose decomposition; generation of hydroxyl radicals putatively acting on cellulose | 4 (2, 3) | B |
| Enzymes related to chitinolysis and aminosugar metabolism | |||
| GH18: chitinase (EC 3.2.1.14) | Chitin degradation | 12 (4, 9) | A, B |
| GH20: β-N-acetylhexosaminidase (EC 3.2.1.52) | Chitobiose hydrolysis | 15 (9, 8) | A, B |
| GH30: putative glucan endo-1,6-β-glucosidase (EC 3.2.1.75) | Microbial glucan degradation (e.g. fungal cell walls) | 2 (1, 1) | A |
| GH114: putative endo-α-1,4-polygalactosaminidase (EC 3.2.1.109) | Glucan degradation (e.g. fungal cell walls) | 10 (6, 4) | A |
| CE1: S-formylglutathione hydrolase (EC 3.1.2.12) | Methane cycle (or nitrogen cycle) | 8 (4, 5) | A |
| CE9: amidohydrolase (EC 3.5.-.-) or putative N-acetylglucosamine-6-phosphate deacetylase (EC 3.5.1.25) | Internal aminosugar metabolism, nitrogen cycle | 9 (7, 3) | B |
#Fungal phyla: A – ascomycetes, B – basidiomycetes, Z – zygomycetes.
§GH – glycoside hydrolase family and CE – carbohydrate esterase family according to www.cazy.org [37].