TY - JOUR
T1 - Stearoyl-acyl carrier protein desaturase gene from the oleaginous microalga Chlorella zofingiensis
T2 - Cloning, characterization and transcriptional analysis
AU - Liu, Jin
AU - Sun, Zheng
AU - Zhong, Yujuan
AU - Huang, Junchao
AU - Hu, Qiang
AU - Chen, Feng
N1 - Funding Information:
Acknowledgments This study was partially supported by a grant from the 985 Project of Peking University. We thank Dr. Henri Gerken (Arizona State University, Mesa, USA) for his kind suggestions on the polish of the manuscript. The project was partially supported by the State Oceanic Administration of China.
PY - 2012/12
Y1 - 2012/12
N2 - The green alga Chlorella zofingiensis can accumulate high level of oleic acid (OA, C18:1△9) rich oils in response to stress conditions. To understand the regulation of biosynthesis of fatty acid in particular OA at the molecular level, we cloned and characterized the stearoyl acyl carrier protein (ACP) desaturase (SAD) responsible for OA formation through desaturation of stearic acid (C18:0) from C. zofingiensis. Southern blot indicated that the C. zofingiensis genome contained a single copy of SAD, from which the deduced amino acid sequence shared high identity to the corresponding homologs from other microalgae and higher plants. The desaturation activity of SAD was demonstrated in vitro using C18:0-ACP as a substrate. Stress conditions such as high light (HL), nitrogen deficiency (N-), or combination of HL and N- (HL + N-) drastically up-regulated the transcripts of biotin carboxylase (BC, a subunit of ACCase) and SAD, and therefore induced considerably the cellular accumulation of total fatty acids including OA. Glucose (50 mM) gave rise to the similar up-regulation of the two genes and induction of fatty acid accumulation. The accumulation of intracellular reactive oxygen species was found to be associated with the up-regulation of genes. This is the first report of characterization of Chlorella-derived SAD and the results may contribute to understanding of the mechanisms involved in fatty acid/lipid biosynthesis in microalgae.
AB - The green alga Chlorella zofingiensis can accumulate high level of oleic acid (OA, C18:1△9) rich oils in response to stress conditions. To understand the regulation of biosynthesis of fatty acid in particular OA at the molecular level, we cloned and characterized the stearoyl acyl carrier protein (ACP) desaturase (SAD) responsible for OA formation through desaturation of stearic acid (C18:0) from C. zofingiensis. Southern blot indicated that the C. zofingiensis genome contained a single copy of SAD, from which the deduced amino acid sequence shared high identity to the corresponding homologs from other microalgae and higher plants. The desaturation activity of SAD was demonstrated in vitro using C18:0-ACP as a substrate. Stress conditions such as high light (HL), nitrogen deficiency (N-), or combination of HL and N- (HL + N-) drastically up-regulated the transcripts of biotin carboxylase (BC, a subunit of ACCase) and SAD, and therefore induced considerably the cellular accumulation of total fatty acids including OA. Glucose (50 mM) gave rise to the similar up-regulation of the two genes and induction of fatty acid accumulation. The accumulation of intracellular reactive oxygen species was found to be associated with the up-regulation of genes. This is the first report of characterization of Chlorella-derived SAD and the results may contribute to understanding of the mechanisms involved in fatty acid/lipid biosynthesis in microalgae.
KW - Chlorella zofingiensis
KW - High light
KW - Nitrogen deficiency
KW - Oleic acid
KW - Stearoyl-acyl carrier protein desaturase
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U2 - 10.1007/s00425-012-1718-7
DO - 10.1007/s00425-012-1718-7
M3 - Article
C2 - 22855030
AN - SCOPUS:84869492390
SN - 0032-0935
VL - 236
SP - 1665
EP - 1676
JO - Planta
JF - Planta
IS - 6
ER -