RNAseq study on the interaction of colonization with elevated temperature on coral larvae

Endosymbiosis between most corals and their photosynthetic dinoflagellate partners begins early in the host life history, when corals are larvae or juvenile polyps. The capacity of coral larvae to buffer climate-induced stress while in the process of symbiont acquisition could come with physiological trade-offs that alter larval behavior, development, settlement and survivorship. We examined the joint effects of thermal stress and symbiosis onset on host gene expression of Acropora digitifera larvae. Pooled larvae (~300 per replicate) were placed in a factorial design: AC= aposymbiotic at control temperature (27deg C); AH= aposymbiotic at high temperature (32deg C); SC= colonization at control temperature; SH= colonization at high temperature. Samples were collected at 1 day and 3 days post-treatment with 6 replicates per treatment. Total RNA was isolated from the pooled larvae and sequenced on Illumina Genome Analyzer IIx platform. At 3 days post-treatment, metamorphosis was detected in some samples to differing degrees indicated in the sample metadata. Our analysis suggests that colonization may hinder larval survival and recruitment under projected climate scenarios.