AUTHOR=Chieu Hoang Dinh , Turner Luke , Smith Meaghan K. , Wang Tianfang , Nocillado Josephine , Palma Peter , Suwansa-ard Saowaros , Elizur Abigail , Cummins Scott F. 

TITLE=Aquaculture Breeding Enhancement: Maturation and Spawning in Sea Cucumbers Using a Recombinant Relaxin-Like Gonad-Stimulating Peptide

JOURNAL=Frontiers in Genetics

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2019.00077

DOI=10.3389/fgene.2019.00077

ISSN=1664-8021

ABSTRACT=<p>Wild sea cucumber resources have been rapidly exhausted and therefore there is an urgent need to develop approaches that will help restocking. Currently, there is a lack of information regarding the genes involved in sea cucumber reproductive processes. The neurohormone relaxin-like gonad-stimulating peptide (RGP) has been identified as the active gonad-stimulating peptide in sea stars (Asteroidea), which could also be present in other echinoderm groups. In this study, a sea cucumber RGP was identified and confirmed by phylogenetic analysis. A recombinant <italic>Holothuria scabra</italic> RGP was produced in the yeast <italic>Pichia pastoris</italic> and confirmed by mass spectrometry. To assess bioactivity, four levels of purification were tested in an <italic>in vitro</italic> germinal vesicle breakdown (GVBD) bioassay. The most pure form induced 98.56 ± 1.19% GVBD in <italic>H. scabra</italic> and 89.57 ± 1.19% GVBD in <italic>Holothuria leucospilota</italic>. Cruder levels of purification still resulted in some GVBD. Upon single injection into female <italic>H. scabra</italic>, the recombinant RGP induced head waving behavior followed by spawning within 90–170 min. Spawned oocytes were fertilized successfully, larvae settled and developed into juveniles. Our results provide a key finding for the development of a break-through new artificial breeding approach in sea cucumber aquaculture.</p>