Molecular Cloning and Expression Analysis of Genes Encoding Two Microsomal Oleate Desaturases (FAD2) from Safflower (Carthamus tinctorius L.)

• Published in: Plant molecular biology reporter Vol. 30; no. 1; pp. 139 - 148
• Main Authors: Guan, Ling-Liang, Wang, Yuan-Biao, Shen, Hao, Hou, Kai, Xu, Ying-Wen, Wu, Wei
• Format: Journal Article
• Language: English
• Published: New York Springer-Verlag 01.02.2012; Springer Nature B.V
• Subjects: Bioinformatics; Biomedical and Life Sciences; Carthamus tinctorius; Cloning; Desaturase; Endoplasmic reticulum; FAD2 gene; Gene expression; Histidine; Leaves; Life Sciences; Linoleic acid; Low temperature; Metabolomics; Plant Breeding/Biotechnology; Plant Sciences; Plants (botany); Polymerase chain reaction; Proteomics; Roots; Seeds; Stems; Temperature effects; Tissues; Transcription; Microsomal oleate desaturase; Safflower; Cold stress; Real-time PCR; Linoleic acid
• ISSN: 0735-9640; 1572-9818
• DOI: 10.1007/s11105-011-0322-5

The endoplasmic reticulum (ER)-associated oleate desaturase (FAD2) is the key enzyme responsible for the production of linoleic acid in plants. In safflower, a seed-type FAD2 gene ( CtFAD2-1 ) has been isolated previously. In this study, two different cDNA sequences, designated CtFAD2-2 and CtFAD2-3 , encoding two microsomal oleate desaturases have been isolated from safflower ( Carthamus tinctorius L.) using a polymerase chain reaction (PCR) approach. Both deduced amino acid sequences showed the three histidine boxes characteristic of all membrane-bound desaturases, and possess a C-terminal ER retention signal. Phylogentic analysis shows that CtFAD2-2 is grouped with other house-keeping type FAD2 sequences from oil crops, while CtFAD2-3 does not belong to seed type or house-keeping type FAD2 . Real-time PCR analysis showed that CtFAD2-2 gene is constitutively expressed in both vegetative tissues and developing seeds, with higher transcript levels in roots, stems and petioles. Transcript of CtFAD2-3 was strongly detected in developing seeds, showing low levels in vegetative tissues. In response to low-temperature stress, CtFAD2-2 and CtFAD2-3 in different tissues showed a different behavior (up- or down-regulated). The transcript of CtFAD2-2 was dramatically decreased in roots, stems and petioles under low temperature, while CtFAD2-3 showed a significant increase in these tissues. On the contrary, in leaves, the strongly enhanced expression of CtFAD2-2 was observed under low temperature, while the transcript of CtFAD2-3 showed a little decrease.