Giant clams harbor dinoflagellates generally of the three genera ( Symbiodinium , Cladocopium , and Durusdinium ) of phototrophic Symbiodiniaceae. Coccoid dinoflagellates (alias zooxanthellae) are found mainly inside zooxanthellal tubules located in the colorful outer mantle. The symbionts need to obtain carbon, nitrogen and phosphorus from the host for growth and metabolism. The host can absorb exogenous ammonia through the c...

Giant clams display light-enhanced inorganic phosphate (P i ) absorption, but how the absorbed P i is translocated to the symbiotic dinoflagellates living extracellularly in a tubular system is unknown. They can accumulate P i in the kidney, but the transport mechanism remains enigmatic. This study aimed to elucidate the possible functions of sodium-dependent phosphate transporter protein 1-homolog (PiT1-like), which co-transp...