TY - JOUR
T1 - Role of C4 carbon fixation in Ulva prolifera, the macroalga responsible for the world’s largest green tides
AU - Liu, Dongyan
AU - Ma, Qian
AU - Valiela, Ivan
AU - Anderson, Donald M.
AU - Keesing, John K.
AU - Gao, Kunshan
AU - Zhen, Yu
AU - Sun, Xiyan
AU - Wang, Yujue
PY - 2020/12/1
Y1 - 2020/12/1
N2 - Most marine algae preferentially assimilate CO2 via the Calvin-Benson Cycle (C3) and catalyze HCO3− dehydration via carbonic anhydrase (CA) as a CO2-compensatory mechanism, but certain species utilize the Hatch-Slack Cycle (C4) to enhance photosynthesis. The occurrence and importance of the C4 pathway remains uncertain, however. Here, we demonstrate that carbon fixation in Ulva prolifera, a species responsible for massive green tides, involves a combination of C3 and C4 pathways, and a CA-supported HCO3− mechanism. Analysis of CA and key C3 and C4 enzymes, and subsequent analysis of δ13C photosynthetic products showed that the species assimilates CO2 predominately via the C3 pathway, uses HCO3− via the CA mechanism at low CO2 levels, and takes advantage of high irradiance using the C4 pathway. This active and multi-faceted carbon acquisition strategy is advantageous for the formation of massive blooms, as thick floating mats are subject to intense surface irradiance and CO2 limitation.
AB - Most marine algae preferentially assimilate CO2 via the Calvin-Benson Cycle (C3) and catalyze HCO3− dehydration via carbonic anhydrase (CA) as a CO2-compensatory mechanism, but certain species utilize the Hatch-Slack Cycle (C4) to enhance photosynthesis. The occurrence and importance of the C4 pathway remains uncertain, however. Here, we demonstrate that carbon fixation in Ulva prolifera, a species responsible for massive green tides, involves a combination of C3 and C4 pathways, and a CA-supported HCO3− mechanism. Analysis of CA and key C3 and C4 enzymes, and subsequent analysis of δ13C photosynthetic products showed that the species assimilates CO2 predominately via the C3 pathway, uses HCO3− via the CA mechanism at low CO2 levels, and takes advantage of high irradiance using the C4 pathway. This active and multi-faceted carbon acquisition strategy is advantageous for the formation of massive blooms, as thick floating mats are subject to intense surface irradiance and CO2 limitation.
UR - http://www.scopus.com/inward/record.url?scp=85090342666&partnerID=8YFLogxK
U2 - 10.1038/s42003-020-01225-4
DO - 10.1038/s42003-020-01225-4
M3 - Article
C2 - 32895472
AN - SCOPUS:85090342666
SN - 2399-3642
VL - 3
JO - Communications Biology
JF - Communications Biology
IS - 1
M1 - 494
ER -
