Fig. 3: Phytoplankton bloom associated bacteria encode a multitude of α-glucan-degrading enzymes.
A Maximum likelihood tree of the main GH13s encoded in the α-glucan PULs of 53 bloom-associated flavobacterial isolates as well as PUL-associated GH13s from the top 50 expressed MAGs of the 2020 Helgoland spring bloom17. Groups are clustered for clarity with arrows indicating group size. Numbers under the enzyme descriptions represent the number of sequences in the group with the included number of MAG-associated sequences in parenthesis. Colored arrows correspond to (B) characterization of representative Polaribacter sp. Hel_I_88 GH13 enzymes. 25 μg protein were incubated with 0.5% poly- or oligosaccharide for 24 h. Shown are all non-0 values (dots) with standard deviation (bars) and mean (white lines) activity of recombinantly produced enzyme on different oligo- and polysaccharides measured via DNS-assay (all values corrected against oligo-/polysaccharide without enzyme, n = 3). Significance to controls containing laminarin with enzyme is indicated by asterisks above the respective bars (one-sided Student’s t test, significant to *0.05, **0.005, ***0.0005). M Maltose, M3 Maltotriose, IM3 Isomaltotriose, Pan Panose, IPan Isopanose, M5 Maltopentose, α-cyc α-Cyclodextrin, β-cyc β-Cyclodextrin, Pul Pullulan, Gly Glycogen, Dex Dextrin, Lam Laminarin. See also Supplementary Fig. S5 for corresponding degradation patterns investigated via FACE and TLC.
