caa a22 4500 445889497 CHVBK 20180317145611.0 cr unu---uuuuu 170323e20110901xx s 000 0 eng 10.1007/s11120-010-9614-0 doi (NATIONALLICENCE)springer-10.1007/s11120-010-9614-0 Photosynthetic characteristics of a multicellular green alga Volvox carteri in response to external CO2 levels possibly regulated by CCM1/CIA5 ortholog [Elektronische Daten] [Takashi Yamano, Akimitsu Fujita, Hideya Fukuzawa] When CO2 supply is limited, aquatic photosynthetic organisms induce a CO2-concentrating mechanism (CCM) and acclimate to the CO2-limiting environment. Although the CCM is well studied in unicellular green algae such as Chlamydomonas reinhardtii, physiological aspects of the CCM and its associated genes in multicellular algae are poorly understood. In this study, by measuring photosynthetic affinity for CO2, we present physiological data in support of a CCM in a multicellular green alga, Volvox carteri. The low-CO2-grown Volvox cells showed much higher affinity for inorganic carbon compared with high-CO2-grown cells. Addition of ethoxyzolamide, a membrane-permeable carbonic anhydrase inhibitor, to the culture remarkably reduced the photosynthetic affinity of low-CO2 grown Volvox cells, indicating that an intracellular carbonic anhydrase contributed to the Volvox CCM. We also isolated a gene encoding a protein orthologous to CCM1/CIA5, a master regulator of the CCM in Chlamydomonas, from Volvox carteri. Volvox CCM1 encoded a protein with 701 amino acid residues showing 51.1% sequence identity with Chlamydomonas CCM1. Comparison of Volvox and Chlamydomonas CCM1 revealed a highly conserved N-terminal region containing zinc-binding amino acid residues, putative nuclear localization and export signals, and a C-terminal region containing a putative LXXLL protein-protein interaction motif. Based on these results, we discuss the physiological and genetic aspects of the CCM in Chlamydomonas and Volvox. Springer Science+Business Media B.V., 2011 CO2-concentrating mechanism nationallicence Carbonic anhydrase nationallicence CCM1 nationallicence Chlamydomonas reinhardtii nationallicence Volvox carteri nationallicence Yamano Takashi Graduate School of Biostudies, Kyoto University, 606-8502, Kyoto, Japan aut Fujita Akimitsu Graduate School of Biostudies, Kyoto University, 606-8502, Kyoto, Japan aut Fukuzawa Hideya Graduate School of Biostudies, Kyoto University, 606-8502, Kyoto, Japan aut Photosynthesis Research Springer Netherlands 109/1-3(2011-09-01), 151-159 0166-8595 109:1-3<151 2011 109 11120 https://doi.org/10.1007/s11120-010-9614-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11120-010-9614-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yamano Takashi Graduate School of Biostudies, Kyoto University, 606-8502, Kyoto, Japan aut NATIONALLICENCE 700 1- Fujita Akimitsu Graduate School of Biostudies, Kyoto University, 606-8502, Kyoto, Japan aut NATIONALLICENCE 700 1- Fukuzawa Hideya Graduate School of Biostudies, Kyoto University, 606-8502, Kyoto, Japan aut NATIONALLICENCE 773 0- Photosynthesis Research Springer Netherlands 109/1-3(2011-09-01), 151-159 0166-8595 109:1-3<151 2011 109 11120 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer