Genotypic variation in disease susceptibility among cultured stocks of elkhorn and staghorn corals

Margaret W Miller; Philip J Colburn; Emma Pontes; Dana E Williams; Allan J Bright; Xaymara M Serrano; Esther C Peters

doi:10.7717/peerj.6751

Genotypic variation in disease susceptibility among cultured stocks of elkhorn and staghorn corals

PeerJ. 2019 Apr 8:7:e6751. doi: 10.7717/peerj.6751. eCollection 2019.

Authors

Margaret W Miller^{1

2}, Philip J Colburn³, Emma Pontes³, Dana E Williams^{1

3}, Allan J Bright^{1

3}, Xaymara M Serrano^{3

4}, Esther C Peters⁵

Affiliations

¹ Southeast Fisheries Science Center, NOAA-National Marine Fisheries Service, Miami, FL, USA.
² SECORE International, Miami, FL, USA.
³ Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA.
⁴ Atlantic Oceanographic and Meterological Laboratory, NOAA Oceanic and Atmospheric Research, Miami, FL, USA.
⁵ Department of Environmental Science and Policy, George Mason University, Fairfax, VA, USA.

Abstract

Disease mortality has been a primary driver of population declines and the threatened status of the foundational Caribbean corals, Acropora palmata and A. cervicornis. There remain few tools to effectively manage coral disease. Substantial investment is flowing into in situ culture and population enhancement efforts, while disease takes a variable but sometimes high toll in restored populations. If genetic resistance to disease can be identified in these corals, it may be leveraged to improve resistance in restored populations and possibly lead to effective diagnostic tests and disease treatments. Using a standardized field protocol based on replicated direct-graft challenge assays, we quantified this important trait in cultured stocks from three field nurseries in the Florida Keys. Field tests of 12 genotypes of A. palmata and 31 genotypes of A. cervicornis revealed significant genotypic variation in disease susceptibility of both species measured both as risk of transmission (percent of exposed fragments that displayed tissue loss) and as the rate of tissue loss (cm² d^-1) in fragments with elicited lesions. These assay results provide a measure of relative disease resistance that can be incorporated, along with consideration of other important traits such as growth and reproductive success, into restoration strategies to yield more resilient populations.

Keywords: Acropora cervicornis; Acropora palmata; Challenge assay; Coral nursery; Disease resistance; Florida Keys; Restoration.

Grants and funding

This project was supported by the National Oceanic and Atmospheric Administration’s Coral Reef Conservation Program and NOAA’s Southeast Fisheries Science Center. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.