Fig. 1
From: Putative ligand binding sites of two functionally characterized bark beetle odorant receptors
Maximum likelihood tree of beetle odorant receptors (ORs). The tree is based on a MAFFT alignment of amino acid sequences, constructed using RaXML, and rooted with the Orco lineage. Included are ORs from Ips typographus (Ityp; blue), Dendroctonus ponderosae (Dpon; red), Anoplophora glabripennis (Agla; green), and the three functionally characterized ORs from Megacyllene caryae (Mcar; black). Major coleopteran OR clades are indicated by the red arcs and numbered according to [44]. Note that OR group 6 is missing in the tree, since this lineage has been lost in species of the Cerambycidae and Curculionidae families. Numbers at nodes represent bootstrap support (n = 100), calculated using RaXML, and are only shown for main lineages and if ≥ 70. Red circles at nodes indicate the seventeen highly supported (bootstrap ≥ 90) simple ItypOR/DponOR orthologs. Key ligands for functionally characterized ORs indicated in the tree (data for McarORs from [39]): A = (2S,3R)-2,3-hexanediol (McarOR20); B = (S)-2-methylbutan-1-ol (McarOR3); C = 2-phenylethanol (McarOR5); IE = (S)-(−)-ipsenol (ItypOR46); ID = (R)-(−)-ipsdienol (ItypOR49). The sources of sequence data and explanation of receptor suffixes are detailed in the “Methods” section