Rubisco expression in the dinoflagellate Symbiodinium sp. is influenced by both photoperiod and endosymbiotic lifestyle.
Although the importance of anthozoan-dinoflagellate (genus Symbiodinium) endosymbioses in the establishment of coral reef ecosystems is evident, little is known about the molecular regulation of photosynthesis in the intra-gastrodermal symbiont communities, particularly with respect to the rate-limiting Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco). In this study, we analyzed rubisco mRNA (rbcL) and protein (RBCL) concentrations over the diel cycle in both cultured and endosymbiotic Symbiodinium samples. In the former, rbcL expression increased upon illumination and decreased during the dark, a pattern that was upheld under continual dark incubation. A different trend in rbcL expression was observed in endosymbiotic Symbiodinium residing within sea anemone (Aiptasia pulchella) tissues, in which illumination gradually led to decreased rbcL mRNA expression. Unexpectedly, RBCL protein expression did not vary over time within anemone tissues, and in neither cultured nor endosymbiotic samples was a correlation between gene and protein expression documented. It appears, then, that photoperiod, lifestyle, and posttranscriptional regulation are all important drivers of RBCL expression in this ecologically important dinoflagellate.
Taiwan Coral Research Center (TCRC), National Museum of Marine Biology and Aquarium, 2 Houwan Rd., Checheng, Pingtung 944, Taiwan, Republic of China.
Anderson B
AB
Mayfield
Yi-Yuong
YY
Hsiao
Hung-Kai
HK
Chen
Chii-Shiarng
CS
Chen
D004141:Dinoflagellida / Q000145:classification / Q000502:physiology* / Q000528:radiation effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology*; D008027:Light; D017440:Photoperiod; D010788:Photosynthesis / Q000502:physiology* / Q000528:radiation effects; D012273:Ribulose-Bisphosphate Carboxylase / Q000096:biosynthesis*; D013045:Species Specificity; D013559:Symbiosis / Q000502:physiology*
D012273:Ribulose-Bisphosphate Carboxylase