Isolation and Characterization of a Stress‐Dependent Plastidial Δ 12 Fatty Acid Desaturase from the Antarctic Microalga Chlorella vulgaris NJ‐7

• Published in: Lipids
• Main Authors: Lu, Yandu, Chi, Xiaoyuan, Li, Zhaoxin, Yang, Qingli, Li, Fuchao, Liu, Shaofang, Gan, Qinhua, Qin, Song
• Other Authors: National Natural Science Foundation of China
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2010
• Subjects: Antarctic; The Antarctic; Antarc*
• Online Access: http://dx.doi.org/10.1007/s11745-009-3381-8; https://onlinelibrary.wiley.com/doi/full/10.1007/s11745-009-3381-8

Abstract An acclimation to the changing physicochemical conditions and high amount of Δ 12 ‐unsaturated fatty acids of the Antarctic Chlorella vulgaris NJ‐7 prompted us to speculate about the involvement of Δ 12 ‐fatty acid desaturases (FAD) in its adaptation to the extremely unfavorable ambience. A full‐length cDNA sequence, designated CvFAD6, was isolated from C. vulgaris NJ‐7 via RT‐PCR and RACE methods. Sequence alignment showed that the gene was homologous to corresponding Δ 12 ‐FAD from other eukaryotes. Phylogenetic analysis showed that it was grouped with plastidial Δ 12 ‐FAD with conserved histidine boxes. Yeast cells transformed with a plasmid construct containing CvFAD6 coding region accumulated a considerable amount of linoleic acid (18:2Δ 9,12 ), normally not present in wild‐type yeast cells, suggesting that the isolated gene encodes a functional Δ 12 enzyme. The correlation between the accumulation of CvFAD6 and temperature has been examined by real time PCR. The analysis showed a constant expression of CvFAD6 from 25 to 15 °C whereas a fourfold increased from 25 to 4 °C. Moreover, CvFAD6 transcription was more sensitive to saline stress since a 20‐fold increase at 6% NaCl was detected. Our data demonstrate that CvFAD6 is the enzyme responsible for the Δ 12 fatty acids desaturation involved in low temperature and high salinity acclimation for Antarctic C. vulgaris NJ‐7.