title: Side-by-side secretion of Late Palaeozoic diverged courtship pheromones in an aquatic salamander.
abstract: Males of the advanced salamanders (Salamandroidea) attain internal fertilization without a copulatory organ by depositing a spermatophore on the substrate in the environment, which females subsequently take up with their cloaca. The aquatically reproducing modern Eurasian newts (Salamandridae) have taken this to extremes, because most species do not display close physical contact during courtship, but instead largely rely on females following the male track at spermatophore deposition. Although pheromones have been widely assumed to represent an important aspect of male courtship, molecules able to induce the female following behaviour that is the prelude for successful insemination have not yet been identified. Here, we show that uncleaved sodefrin precursor-like factor (SPF) protein pheromones are sufficient to elicit such behaviour in female palmate newts (Lissotriton helveticus). Combined transcriptomic and proteomic evidence shows that males simultaneously tail-fan multiple ca 20 kDa glycosylated SPF proteins during courtship. Notably, molecular dating estimates show that the diversification of these proteins already started in the late Palaeozoic, about 300 million years ago. Our study thus not only extends the use of uncleaved SPF proteins outside terrestrially reproducing plethodontid salamanders, but also reveals one of the oldest vertebrate pheromone systems.
authors.affiliation: Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Ines
authors.initials: I
authors.lastname: Van Bocxlaer
authors.affiliation: Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Dag
authors.initials: D
authors.lastname: Treer
authors.affiliation: Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Margo
authors.initials: M
authors.lastname: Maex
authors.affiliation: Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Vandebergh
authors.affiliation: Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Sunita
authors.initials: S
authors.lastname: Janssenswillen
authors.affiliation: Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Gwij
authors.initials: G
authors.lastname: Stegen
authors.affiliation: Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Kok
authors.affiliation: Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Bert
authors.initials: B
authors.lastname: Willaert
authors.affiliation: Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Severine
authors.initials: S
authors.lastname: Matthijs
authors.affiliation: Laboratory of Immunobiology, Department of Microbiology and Immunology, Rega Institute, Katholieke Universiteit Leuven (K.U. Leuven), Minderbroedersstraat 10-Box 1030, 3000 Leuven, Belgium.
authors.forename: Erik
authors.initials: E
authors.lastname: Martens
authors.affiliation: Laboratory of Molecular Immunology, Department of Microbiology and Immunology, Rega Institute, Katholieke Universiteit Leuven (K.U. Leuven), Minderbroedersstraat 10-Box 1030, 3000 Leuven, Belgium.
authors.forename: Anneleen
authors.initials: A
authors.lastname: Mortier
authors.affiliation: Structural and Molecular Microbiology, Structural Biology Research Centre, VIB, Pleinlaan 2, 1050 Brussels, Belgium Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
authors.forename: Henri
authors.initials: H
authors.lastname: de Greve
authors.affiliation: Laboratory of Molecular Immunology, Department of Microbiology and Immunology, Rega Institute, Katholieke Universiteit Leuven (K.U. Leuven), Minderbroedersstraat 10-Box 1030, 3000 Leuven, Belgium.
authors.forename: Paul
authors.initials: P
authors.lastname: Proost
authors.affiliation: Amphibian Evolution Laboratory, Biology Department, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium fbossuyt@vub.ac.be.
authors.forename: Franky
authors.initials: F
authors.lastname: Bossuyt
mesh_terms: D000595:Amino Acid Sequence; D029845:Amphibian Proteins / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D003380:Courtship; D005260:Female; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D020543:Proteome; D012724:Sex Attractants / Q000235:genetics / Q000378:metabolism*; D012726:Sexual Behavior, Animal; D013045:Species Specificity; D059467:Transcriptome; D014562:Caudata / Q000235:genetics / Q000502:physiology*
chemical_list: D029845:Amphibian Proteins; D020543:Proteome; D012724:Sex Attractants
keywords: amphibians; evolution; gene duplications; phylogeny; protein pheromones