Linking coral fluorescence phenotypes to thermal bleaching in the reef-building from the northern South China Sea.

UNLABELLED

Coral fluorescence phenotypes have been suggested as an adaptation to a broad range of environmental conditions, yet the mechanisms linking thermal bleaching tolerance in reef-building coral populations, associated with fluorescence phenotypes due to GFP-like proteins, remains unclear. In this study, the relationship between the thermal sensitivity and phenotypic plasticity of corals was investigated using two phenotypes of green and brown. The results reveal that brown was more susceptible to bleaching than green when exposed to a higher growth temperature of 32 °C. Both phenotypes of were associated with the thermotolerant Symbiodiniaceae symbiont, . However, the brown showed a significant decrease in Symbiodiniaceae cell density and a significant increase in pathogenic bacteria abundance when the growth temperature was raised from 29 to 32 °C. The physiological traits and transcriptomic profiles of Symbiodiniaceae were not notably affected, but there were differences in the transcriptional levels of certain genes between the two phenotype hosts of Under heat stress of 32 °C, the gene encoding green fluorescent protein (GFP)-like and chromosome-associated proteins, as well as genes related to oxidative phosphorylation, cell growth and death showed lower transcriptional levels in the brown compared to the green Overall, the results demonstrate that the green form of is better able to tolerate ocean warming and defend against pathogenic bacteria, likely due to higher gene transcription levels and defense ability.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s42995-023-00190-1.