“Corals from Taiwan’s thermally extreme reefs carry distinct proteomic fingerprints that reveal how life adapts to constant environmental turbulence.”
Seriatopora spp.-rich reef
I used quantitative iTRAQ proteomics to investigate how the coral Seriatopora hystrix and its algal symbionts respond to naturally variable versus stable thermal environments in southern Taiwan. Building on earlier reciprocal transplant experiments, corals from upwelling reefs with dramatic daily temperature swings and nearby stable reefs were exposed in the laboratory to either constant or fluctuating temperature regimes. Rather than finding widespread heat-stress signatures, the study revealed that corals performed best and displayed the most distinctive molecular profiles when maintained under their “native” thermal conditions. Much of this signal came from Symbiodiniaceae proteins involved in Golgi-mediated lipid trafficking and photosynthetic processes, suggesting that regulation of energy transport and host-symbiont metabolic exchange may underpin acclimatization to thermodynamically extreme reefs. The work also highlighted a striking disconnect between gene expression and protein abundance, reinforcing the importance of proteomics for understanding coral physiology beyond transcriptomics alone. More broadly, the study argued that coral resilience is not simply a matter of stress tolerance, but instead reflects finely tuned, site-specific molecular organization shaped by long-term exposure to environmental variability.
Details: I froze samples from the Seriatopora hystrix variable temperature study (SHVTS) for years (nine to be exact), just hoping that proteomic methodologies would 1) improve and 2) drop in price. Thankfully, both happened, so I used funds from the Friendly Bear Editorial Service and crowd sourcing (thanks everyone!) to analyze the proteins synthesized by a subset of corals from the experiments: upwelling reef corals exposed to stable or variable temperatures and non-upwelling corals exposed to these same treatments.
The manuscript was published in August 2020 in Microorganisms, and I have submitted all data (RAW MS files, MZID files, MZML files, and the corresponding tab-delineated spreadsheets) to three repositories:
The University of California San Diego’s MASSive Repository (accession MSV000085863)
Proteome Xchange (accession: PXD020679)
Basically, of the thousands of proteins sequenced, I focused on 30; check on the breakdown in this figure. DCP=differentially concentrated proteins (i.e., the ones that responded to experimental treatment). POIs= “proteins of interest” (in a nutshell, the ones that are useful for predicting coral responses to environmental change).
Looking at the proteins in a multivariate context: principal components analysis (PCA) and multi-dimensional scaling (MDS; similarity). S=stable temperature samples. V=variable temperature samples. You can see some pretty good separation by site: Houbihu (upwelling reef; green) vs. Houwan (non-upwelling; black). The corals exposed to their “native” conditions are most distinct from one another: Houbihu-variable (green V’s) vs. Houwan-stable (black S’s).
These are the proteins that essentially changed the most. I am particularly interested in the top two Symbiodinaceae proteins since they were both higher under native conditions and involved in the same cellular process: Golgi-mediated lipid and protein trafficking. We actually have a number of coral lipid trafficking papers, so we might be able to run with this (i.e., the role of this cellular process in thermal acclimation).
The final plots/data below are getting at one of my current (mid-2020) pet projects: predicting coral health. This particular technique, which is not the only one out there for this kind of exercise, is known as stepwise discriminant analysis (SDA). Basically, it is showing me the minimum number of proteins that can be used to build a statistical model that would permit me to predict the coral response to an experimental factor with 100% confidence. For this study, it may make less sense since it was carried out in a controlled laboratory setting and the data are inherently explanatory in nature. However, if you sampled a coral from a reef and did not know much about its thermal history, you could look at three proteins (the three vectors in b) and see if it was being exposed to stable or variable temperatures in the days leading up to sampling. Ultimately, this approach is more geared towards stress studies (i.e., estimating risk for corals exposed to, for instance, high temperatures for a prolonged period).
Taken together, this work highlights how coral resilience emerges not from a single “stress gene” or universal thermal threshold, but from coordinated, system-wide adjustments shaped by environmental history. By combining ecologically realistic thermal experiments with advanced quantitative proteomics, the study revealed that corals from thermodynamically variable reefs possess highly distinctive molecular architectures that persist even after transplantation into new conditions. Particularly striking was the central role of the algal symbionts, whose proteins involved in lipid trafficking, photosynthesis, and cellular regulation appeared disproportionately important in explaining acclimatization patterns. The findings therefore reinforce the idea that coral thermotolerance is fundamentally a property of the entire holobiont rather than the animal host alone. More broadly, the paper helped push coral reef science toward a more mechanistic and integrative framework, one that recognizes resilience as a dynamic, emergent property arising from interactions among physiology, symbiosis, molecular regulation, and environmental variability across scales.