Stress response
Bacterial stress response genes in the coral SML metagenomes were not
affected by heat stress (Fig. 3A). Metagenomics describes the relative
abundance of genes in the microbiome which identifies functional genes
that are potentially being selected by the microbiome under those
conditions (Dinsdale et al. 2008a; Coelho et al. 2022) and it does not
measure which functional genes are being expressed at the point the
sample was taken. Therefore, bacterial stress response gene expression
could be increased under heat stress, although the metagenomes show that
they are potentially not being selected by the coral SML microbiome over
the experiment to respond to stress. Future studies coupling
metagenomics to metatranscriptomics could elucidate the changes in
stress response genes in the coral microbiome under heat stress.
However, our metagenomes showed that bacterial genes related to nitrogen
and sulfur metabolism strongly responded to heat stress and were
potentially selected in the coral SML microbiome of P. strigosa .