Chlamydomonas sp. ICE-L which can thrive in extreme environments of the Antarctic is a major biomass producer. The FAD genes in Chlamydomonas sp. ICE-L were obtained and sequence alignment showed that these genes are homologous to known FADs with conserved histidine motifs. In this study, we analyzed the transcription of five FADs and FA compositions at different temperatures. The results showed that the expressions of Delta 9CiFAD, omega 3CiFAD1 and omega 3CiFAD2 were apparently up-regulated at 0 degrees C, however, the up-regulation of Delta 6CiFAD intensified with rising temperature. Meanwhile, analysis of the FA compositions showed that PUFAs were dominant compositions, accounting for more than 75% TFA in Chlamydomonas sp. ICE-L Furthermore, PUFAs were significantly increased at 0 and 5 degrees C, which may be attributed to higher proportions of C18:3 and C20:3. Moreover, PUFAs were significantly decreased at 15 degrees C whereas SFAs were significantly increased. (C) 2013 Elsevier Ltd. All rights reserved.