Non-Specific Expression of Fertilization Genes in the Crown-of-Thorns Acanthaster Cf. Solaris: Unexpected Evidence of Hermaphroditism in a Coral Reef Predator

Peer reviewed: 
Yes, item is peer reviewed.
Scholarly level: 
Faculty/Staff
Final version published as: 

Guerra, V., Haynes, G., Byrne, M., Yasuda, N., Adachi, S., Nakamura, M., Nakachi, S. and Hart, M.W. (2019), Non‐specific expression of fertilization genes in the crown‐of‐thorns Acanthaster cf. solaris: unexpected evidence of hermaphroditism in a coral reef predator. Molecular Ecology. (2019). doi:10.1111/mec.15332

Date created: 
2019-12-14
Identifier: 
DOI: 10.1111/mec.15332
Keywords: 
Acanthaster
Bindin
Outbreaks
Reproductive assurance
RNA-seq
Abstract: 

The characterization of gene expression in gametes has advanced our understanding of the molecular basis for ecological variation in reproductive success and the evolution of reproductive isolation. These advances are especially significant for ecologically important keystone predators such as the coral-eating crown-of-thorns sea stars (COTS, Acanthaster) which are the most influential predator species in Indo-Pacific coral reef ecosystems and the focus of intensive management efforts. We used RNA-seq and transcriptome assemblies to characterize the expression of genes in mature COTS gonads. We described the sequence and domain organization of eight genes with sex-specific expression and well known functions in fertilization in other echinoderms. We found unexpected expression of genes in one ovary transcriptome that are characteristic of males and sperm, including genes that encode the sperm specific guanylate cyclase receptor for an egg pheromone, and the sperm acrosomal protein bindin. In a reassembly of previously published RNA-seq data from COTS testes, we found a complementary pattern: strong expression of four genes that are otherwise well known to encode egg-specific fertilization proteins, including the egg receptor for bindin (EBR1) and the acrosome reaction-inducing substance in the egg coat (ARIS1, ARIS2, ARIS3). We also found histological evidence of both eggs and sperm developing in the same gonad in several COTS individuals from a parallel study. These results suggest the occurrence of hermaphrodites, and the potential for reproductive assurance via self-fertilization. Our findings have implications for management of COTS populations, especially in consideration of the large size and massive fecundity of these sea stars.

Description: 

The full-text of this manuscript will be available in December 2020 in keeping with the 12 month embargo period of the journal Molecular Ecology and its publisher Wiley. If you require access prior to December 2020 please contact summit@sfu.ca

Language: 
English
Document type: 
Article
Rights: 
Rights remain with the authors.
Sponsor(s): 
Natural Sciences and Engineering Research Council of Canada (NSERC)
Genome BC
Japan Society for the Promotion of Science
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