Host proteins and symbiotic bacteria mediate the thermal response differences of the two color phenotypes of Porites lutea to extreme marine heatwaves in Weizhou Island

作者：Wang Y, Yu K, Meng L, Gong S, Yu X, Huang X, Huang W · 发表于：Marine pollution bulletin · 年份：2026 · DOI：10.1016/j.marpolbul.2026.119723 · 研究领域：Anthozoa、Animals、Symbiosis、Phenotype、Coral Reefs、Global Warming、China、Hot Temperature、Coral Bleaching、Pigmentation、Bacteria、Color

Extreme marine heatwaves driven by global warming are the major threat to coral reefs, causing mass coral bleaching and mortality. Color polymorphism is a key coral phenotypic trait, but the mechanisms underlying thermal adaptability differences among color phenotypes remain unclear. This study investigated two Porites lutea phenotypes (green and brown) from Weizhou Island, integrating field surveys, proteomics, and symbiotic microbial community analyses to explore their thermal response differences and molecular mechanisms. Field monitoring during the 2020 marine heatwave revealed a 46% bleaching rate in brown P. lutea, whereas green P. lutea exhibited no bleaching, demonstrating the latter's superior thermal tolerance. Proteomics revealed that green coral hosts maintained thermal adaptability by regulating proteins related to heat shock response, antioxidant defense, and green fluorescent protein (GFP), with GFP expression significantly upregulated by 7.2-fold compared to the brown phenotype. Additionally, the two phenotypes differed in symbiotic bacterial relative abundance: the green P. lutea was dominated by Proteobacteria and Chloroflexi (aiding nitrogen fixation and photosynthesis), while the brown P. lutea was enriched with Thermus and Prosthecochloris (enhancing antioxidant capacity and thermal resistance). No significant differences were found in the community structure or density of Symbiodiniaceae. In conclusion, differential host protein expression and functional...