Transcriptome Analysis of the Scleractinian Coral Stylophora pistillata

Sarit Karako-Lampert,Didier Zoccola,Oren Levy,Mali Salmon-Divon,Anthony Bertucci,Emeline Deleury,Mark Katzenellenbogen,Denis Allemand,Sylvie Tambutté,Ove Hoegh-Guldberg

doi:10.1371/journal.pone.0088615

Abstract

The principal architects of coral reefs are the scleractinian corals; these species are divided in two major clades referred to as “robust” and “complex” corals. Although the molecular diversity of the “complex” clade has received considerable attention, with several expressed sequence tag (EST) libraries and a complete genome sequence having been constructed, the “robust” corals have received far less attention, despite the fact that robust corals have been prominent focal points for ecological and physiological studies. Filling this gap affords important opportunities to extend these studies and to improve our understanding of the differences between the two major clades. Here, we present an EST library from Stylophora pistillata (Esper 1797) and systematically analyze the assembled transcripts compared to putative homologs from the complete proteomes of six well-characterized metazoans: Nematostella vectensis, Hydra magnipapillata, Caenorhabditis elegans, Drosophila melanogaster, Strongylocentrotus purpuratus, Ciona intestinalis and Homo sapiens. Furthermore, comparative analyses of the Stylophora pistillata ESTs were performed against several Cnidaria from the Scleractinia, Actiniaria and Hydrozoa, as well as against other stony corals separately. Functional characterization of S. pistillata transcripts into KOG/COG categories and further description of Wnt and bone morphogenetic protein (BMP) signaling pathways showed that the assembled EST library provides sufficient data and coverage. These features of this new library suggest considerable opportunities for extending our understanding of the molecular and physiological behavior of “robust” corals.

Highlights

Corals and sea anemones include some of the morphologically simplest metazoan animals
Analyses of the Hydra magnipapillata, Nematostella vectensis and Acropora digitifera genomes have revealed that cnidarians possess homologs of many of the developmental genes that control the axial specification of the Bilaterian body plan [3,6,7,8]
expressed sequence tag (EST) Library Construction and Assembly The normalized and non-normalized cDNA libraries constructed from S. pistillata holobiont RNA starting materials were based on an RNA pool collected from different environmental conditions to maximize the diversity of rarely expressed genes

Summary

Introduction

Corals and sea anemones include some of the morphologically simplest metazoan animals. Cnidarians are characterized as having a single body axis with only two germ layers and two to three cell lineages, which gives rise to a handful of different cell types [2]. This profile suggests an underlying genetic simplicity and that cnidarian body plans are likely to be specified and patterned by a subset of the genes known among ‘higher’ animals. Analyses of the Hydra magnipapillata, Nematostella vectensis and Acropora digitifera genomes have revealed that cnidarians possess homologs of many of the developmental genes that control the axial specification of the Bilaterian body plan [3,6,7,8].

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Conclusion