Investigating calcification-related candidates in a non-symbiotic scleractinian coral, Tubastraea spp.

Abstract

In hermatypic scleractinian corals, photosynthetic fixation of CO2 and the production of CaCO3 are intimately linked due to their symbiotic relationship with dinoflagellates of the Symbiodiniaceae family. This makes it difficult to study ion transport mechanisms involved in the different pathways. In contrast, most ahermatypic scleractinian corals do not share this symbiotic relationship and thus offer an advantage when studying the ion transport mechanisms involved in the calcification process. Despite this advantage, non-symbiotic scleractinian corals have been systematically neglected in calcification studies, resulting in a lack of data especially at the molecular level. Here, we combined a tissue micro-dissection technique and RNA-sequencing to identify calcification-related ion transporters, and other candidates, in the ahermatypic non-symbiotic scleractinian coral Tubastraea spp. Our results show that Tubastraea spp. possesses several calcification-related candidates previously identified in symbiotic scleractinian corals (such as SLC4-γ, AMT-1like, CARP, etc.). Furthermore, we identify and describe a role in scleractinian calcification for several ion transporter candidates (such as SLC13, -16, -23, etc.) identified for the first time in this study. Taken together, our results provide not only insights about the molecular mechanisms underlying non-symbiotic scleractinian calcification, but also valuable tools for the development of biotechnological solutions to better control the extreme invasiveness of corals belonging to this particular genus.

Understanding Snail Mucus Biosynthesis and Shell Biomineralisation through Genomic Data Mining of the Reconstructed Carbohydrate and Glycan Metabolic Pathways of the Giant African Snail (Achatina fulica)

“…The bicarbonate ions are required for the formation of calcium carbonate crystals. Capasso et al [ 53 ] found that the bicarbonate transporter SLC4 regulates intracellular bicarbonate ion homeostasis to buffer excess H + generated during CaCO 3 precipitation and supply of HCO 3 − to the calcifying cells of the mantle tissues [ 53 , 82 ].…”

“… a : Capasso et al [ 53 ], b : Przybyło and Langner [ 54 ], c : Sleight et al [ 55 ], and d : Louis et al [ 56 ]. …”

Complex dynamics of coral gene expression responses to low pH across species

“…Various bicarbonate ion transporters have been reported for different coral species (Zoccola et al., 2015), including downregulation of a SLC4 member under low pH conditions (Yuan et al., 2018); however, the DEGs in our study matched different SLC families. Recently, the role of SLC13 and SLC23 in coral calcification were described for the non‐symbiotic coral Tubastraea (Capasso et al., 2022). The consistent downregulation of various SLC family proteins in corals subject to low pH in our study suggests an impairment of intracellular pH regulation.…”

Nutritional ecology of temperate octocorals in a warming ocean

“…Normally, the first site of NH 4 + uptake in corals is the Symbiodiniaceae component, which assimilates 90% of the NH 4 + taken up via the glutamine synthetase/glutamine oxoglutarate aminotransferase pathway (GS/GOGAT) (Pernice et al, 2012;Roberty et al, 2020). Although the coral host can also assimilate NH 4 + via two pathways (GS/GOGAT and glutamate dehydrogenase pathway), and has ammonium transporters (Capasso et al, 2022), direct NH 4 + uptake is generally low (Pernice et al, 2012), except under certain stress conditions (Tang et al, 2020;Xiang et al, 2020). Unlike Symbiodiniaceae-bearing corals, non-symbiotic corals are generally unable to assimilate DIN (Muscatine et al, 1979) and instead excrete NH 4 + and urea into the surrounding water (Rahav et al, 1989).…”