Lipid characterization of seed oils from high‐palmitic, low‐palmitoleic, and very high‐stearic acid sunflower lines

Abstract

Information obtained in recent years regarding the enzymes involved in FA synthesis can now be applied to develop novel sunflower lines by incorporating enzymes with specific characteristics into lines with a defined background. We have generated three highly saturated mutant lines in this way and characterized their FA content. The new high-palmitic, low-palmitoleic lines CAS-18 and CAS-25, the latter on a high-oleic background, have been selected from the high-stearic mutant CAS-3 by introducing a deficient stearic acid desaturase in a high-palmitic background from the previously developed mutant lines CAS-5 and CAS-12, respectively. As such, the desaturation of palmitic acid and the synthesis of palmitoleic acid and its derivatives (asclepic and palmitolinoleic acids) were reduced in these high-palmitic lines, increasing the stearic acid content. Likewise, introducing a FA thioesterase from a high-palmitic line (e.g., CAS-5) into the high-stearic CAS-3 increased the stearic acid content from 27 to 32% in the new high-stearic line CAS-31. As previously described in high-palmitic lines, high growth temperatures did not reduce the linoleic acid content of the oil. Furthermore, the FA composition of TAG, DAG, and phospholipids was modified in these lines. Besides a high degree of saturation, the TAG from these new vegetable oils have a low content of saturated FA in the sn-2 position. The alpha asymmetric coefficient obtained also indicates that the saturated FA are asymmetrically distributed within the TAG molecules. Indeed, the disaturated TAG content rose from 31.8 to 48.2%. These values of disaturated TAG are the highest to date in a temperate oilseed.

Progress in modification of sunflower oil to expand its industrial value

“…48 The high palmitic acid content sunflower lines CAS-18 and CAS-25 were selected through empirical breeding methods by transferring the mutant stearic acid desaturase gene from CAS-3 in lines CAS-5 and CAS-12 (30.7%, palmitic acid). 49 A line CAS-31 (high stearic acid 32%) was developed by introducing the thioesterase gene from high palmitic acid line CAS-5 (palmitic acid, 25.2%) while disaturated TAG was 48.2%. 49 The medium oleic acid content (50%) was also combined with high stearic acid (15-30%) through initial screening of the genotypes with high thioesterase activity.…”

Improving grain quality: ecophysiological and modeling tools to develop management and breeding strategies

“…High palmitic cultivars, in turn, have been related to a significant decrease of the last step of intraplastidial elongation catalyzed by the FaSii enzyme complex (Salas et al, 2004). inbred lines combining the high stearic with the high oleic trait (high stearic-high oleic) have also been obtained (Serrano-vega et al, 2005). High oleic, high linoleic and high stearic cultivars of soybean have been developed (Schnebly et al, 1996;Stojšin et al, 1998;primomo FIG.…”

“…Data from , Aguirrezábal andPereyra (1998), andIzquierdo (unpublished). et al, 2002;Serrano-vega et al, 2005), but they have not been released to the seed market yet. Low-erucic rapeseed cultivars for human consumption are currently available, as well as high-erucic cultivars for industrial uses (velasco et al, 1999).…”

Effects of technical management on the fatty-acid composition of high-oleic and high-linoleic sunflower cultivars

“…Other fatty-acid profiles exist in sunflower and have been developed for specific industrial needs. Cultivars with "high" stearic or palmitic acid levels have been produced, for example (PerezVich et al, 2002;Fernandez-Moya et al, 2002;Salas et al, 2007;Serrano-Vega et al, 2005). Ongoing plant breeding efforts are continuing to generate sunflower varieties with very high linoleic acid or very high oleic acid contents.…”