Spatial metabolomics for symbiotic marine invertebrates

A mass spectrometry imaging workflow was developed for a soft- and hard-bodied cnidarian animal capable of revealing the host and symbiont metabolome in situ, without the need for a priori isotopic labelling or skeleton decalcification. Through the combination of anaesthetizing, embedding, and cryofilm application, the cryosectioning workflow presented produced intact tissue sections for a soft-bodied (sea anemone E. diaphana) and a hard-bodied (coral G. fascicularis) cnidarian in their natural shape for MSI metabolomics or spatial metabolomics.

The study used:

Soft bodied cnidarians sourced from the GBR - E. diaphana (genotype AIMS4) in symbiosis with the homologous Breviolum minutum (hereafter referred to as B1-anemones, which were inoculated with symbiont culture SCF 127-01) or the heterologous Cladocopium proliferum (C1-anemones) were inoculated with symbiont culture SCF 055-01.10 E. diaphana were sampled 10 mo post-inoculation for MSI and were maintained under ambient temperature of 27°C at 30 μmol m−2 s−1 (12:12 h, light: dark)

Hard-bodied cnidarians, the coral G. fascicularis in symbiosis with Cladocopium C40 (ITS2 profile: C40-C3-C115-C40h) was obtained from Palm Islands GBR and kept under ambient temperature of 27°C and at 130–150 μmol m−2 s−1 at full sun (12:12 h light: dark)

ITS2 profiles of the symbiont cultures:

culture SCF 127-01 - ITS2 profile: B1-B1o-B1p

culture SCF 055-01.10 - ITS2 profile: C1-C1b-C1c-C42.2-C1br-C1bh-C1cb-C72k

Cladocopium C40: ITS2 profile: C40-C3-C115-C40h