Journal Article

Activities of principal photosynthetic enzymes in green macroalga Ulva linza： functional implication of C4 pathway in CO2 assimilation

XU JianFang ZHANG XiaoWen YE NaiHao ZHENG Zhou MOU ShanLi DONG MeiTao XU Dong MIAO JinLai

2013

Overview

The green-tide-forming macroalga Ulva linza was profiled by transcriptome sequencing to ascertain whether the alga carries both C3 and C4 photosynthesis genes. The key enzymes involved in C4 metabolism including pyruvate orthophosphate dikinase （PPDK）, phosphoenolpyruvate carboxylase （PEPC）, and phosphoenolpyruvate carboxykinase （PCK） were found. When meas- ured under normal and different stress conditions, expression of rbcL was higher under normal conditions and lower under the adverse conditions, whereas that of PPDK was higher under some adverse conditions, namely desiccation, high salinity, and low salinity. Both ribulose-1, 5-biphosphate carboxylase （RuBPCase） and PPDK were found to play a role in carbon fixation, with significantly higher PPDK activity across the stress conditions. These results suggest that elevated PPDK activity alters carbon metabolism in U. linza leading to partial operation of the C4 carbon metabolism, a pathway that, under stress conditions probably contributes to the hardy character of U. linza and thus to its wide distribution.

• Publisher: Science China Press
• Subject: Biomedical and Life Sciences / Biosynthetic Pathways / C4途径 / Carbon Cycle - physiology / Carbon Dioxide - metabolism / CO2同化 / Gene Expression Regulation, Enzymologic - drug effects / Gene Expression Regulation, Enzymologic - radiation effects / Gene Expression Regulation, Plant - drug effects / Gene Expression Regulation, Plant - radiation effects / Life Sciences / Light / Phosphoenolpyruvate Carboxykinase (ATP) - genetics / Phosphoenolpyruvate Carboxykinase (ATP) - metabolism / Phosphoenolpyruvate Carboxylase - genetics / Phosphoenolpyruvate Carboxylase - metabolism / Photosynthesis / Plant Proteins - genetics / Plant Proteins - metabolism / Pyruvate, Orthophosphate Dikinase - genetics / Pyruvate, Orthophosphate Dikinase - metabolism / Research Paper / Reverse Transcriptase Polymerase Chain Reaction / Ribulose-Bisphosphate Carboxylase - genetics / Ribulose-Bisphosphate Carboxylase - metabolism / RuBPCase / Salinity / Sodium Chloride - pharmacology / Transcriptome - drug effects / Transcriptome - radiation effects / Ulva - enzymology / Ulva - genetics / Ulva - physiology / Water - metabolism / Water - pharmacology / 丙酮酸磷酸二激酶 / 光合酶 / 大型藻类 / 石莼 / 磷酸烯醇式丙酮酸羧化酶