Devolopmental and growth temperature regulation of omega-3 fatty acid desaturase genes in safflower (Carthamus tinctorius L.)

Abstract

ABSTRACT. Three ω-3 fatty acid desaturase genes (CtFAD3, CtFAD7, and CtFAD8) were isolated from safflower (Carthamus tinctorius L.). Transcript analysis showed that the highest transcript levels were detected for CtFAD3 and the low transcript levels were detected for CtFAD7 and CtFAD8 in flowers. This result indicates that CtFAD3 enzyme activity is important for fatty acid desaturation in flowers. The low transcript level of CtFAD3 in developing seeds was consistent with the recorded high level of linoleic acid (18:2) and lack of linolenic acid (18:3) in safflower seed oil. At low temperatures, the induced transcription levels of ω-3 fatty acid desaturase genes in the stems and petioles were consistent with increased polyunsaturated fatty acids (PUFAs). In the roots, ω-3 fatty acid desaturase noticeably increased at low temperatures, whereas PUFA levels decreased. Interestingly, C18:3 Δ9,12,15 alcohol was specifically found in safflower roots, and showed a significant increase, indicating a flux in the acid to alcohol ratio of this compound in safflower roots.

Genome-Scale Transcriptome Analysis of the Desert Shrub Artemisia sphaerocephala

“…The first histidine motifs are HDCGHH in ctFAD2-5 and HECGHH in ctFAD2-4 and ctFAD2-8. ctFAD2-5 and ctFAD2-8 appear to be root specific, and ctFAD2-4 is highly expressed in young seedling tissues, including cotyledons and hypocotyls [ 68 ]. The second branch includes AsFAD2-10, 17 and 9.…”

“…ctFAD2-2 exhibited significantly increased expression in the cotyledonary tissues of young seedlings. The second histidine motif, HRRHH, is highly conserved in ctFAD2-2, which is a Δ12-oleate desaturase that converts oleic acid to linoleic acid and presumably plays only a secondary role in linoleic acid production in seed oil [ 68 ]. AsFAD2-9 was also situated next to AcFAD2-10 on the second branch.…”

“…AsFAD2-9 was also situated next to AcFAD2-10 on the second branch. AsFAD2-11 and ctFAD2-6 are located next to each other on the third branch, and ctFAD2-6 has been found to be highly expressed in cotyledons and hypocotyls [ 68 ]. In addition, AsFAD2-12 and ctFAD2-10 are located next to each other in the second part.…”

Identification and Evaluation of Reference Genes for Accurate Transcription Normalization in Safflower under Different Experimental Conditions

“…Although EF1α and UBQ were used as reference genes in safflower gene expression analysis with the RT-qPCR technique, the validation of a suitable set of RGs is still of crucial importance [ 48 – 50 ]. This safflower transcriptome analysis identified a group of stably expressed genes under different seed development stages, and these data resources made it convenient for us to select some relatively stable candidate RGs for normalization in order to further identify and evaluate the most appropriate RGs for stable expression across a variety of experimental conditions.…”

Environmental and varietal impact on linseed composition and on oil unidirectional expression process

“…Numerous works have reported the environmental effects on yield, oil content and fatty acids composition of oil, tocopherols, phytosterols, and phospholipids in oilseed plants (Froment et al, 1999;Green, 1986;Trémolière et al, 1982;Tripathi and Agrawal, 2013;Zubr and Matthaus, 2002). Cold is one of parameters directly involved in the increasing of omega-3 content in plant tissues maintaining membrane integrity and their fluidity (Guan et al, 2014;Steindal et al, 2015;Tonnet and Green, 1987).…”