Identification and characterization of a novel bifunctional Δ12/Δ15-fatty acid desaturase gene from Rhodosporidium kratochvilovae
2016
Cui, Jinjin | He, Shiwu | Ji, Xiuling | Lin, Lianbing | Wei, Yunlin | Zhang, Qi
OBJECTIVES: To elucidate the biosynthesis pathway of linoleic acid and α-linolenic acid in Rhodosporidium kratochvilovae YM25235 and investigate the correlation of polyunsaturated fatty acids with its cold adaptation. RESULTS: A 1341 bp cDNA sequence, designated as RKD12, putatively encoding a Δ¹²-desaturase was isolated from YM25235. Sequence analysis indicated that this sequence comprised a complete ORF encoding 446 amino acids of 50.6 kDa. The encoded amino acid sequence shared higher similarity to known fungal Δ¹²-desaturases that are characteristic of three conserved histidine-rich motifs. RKD12 was further transformed into Saccharomyces cerevisiae INVScl for functional characterization. Fatty acid analysis showed the yeast transformants accumulated two new fatty acids: linoleic acid and α-linolenic acid. Furthermore, mRNA expression level of RKD12 and the content of linoleic acid and α-linolenic acid were increased significantly with the culture temperature downshift from 30 to 15 °C, which might be helpful for the cold adaptation of YM25235. CONCLUSION: RKD12 is a novel bifunctional ∆¹²/∆¹⁵-desaturase gene, and the increased RKD12 mRNA expression level and PUFAs content at low temperature might be helpful for the cold adaptation of YM25235.
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