Toward increasing erucic acid content in oilseed rape (Brassica napus L.) through the combination with genes for high oleic acid

摘要

Erucic acid (22:1) is a valuable renewable resource that has several applications in the oleochemical industry. High 22:1 rapeseed (HEAR) contains around 50% 22:1. For its technical use it is desirable to increase the 22:1 content and to decrease the eicosenoic acid (20:1), PUFA (18:2 + 18:3), and saturated FA (16:0 + 18:0) contents. In the present experiment, HEAR was crossed to high oleic acid rapeseed (ca. 85% 18:1) with the hypothesis that a combination of the involved genes should lead to a reduced 18:1 desaturation and to an increased availability of oleoyl-CoA, which should result in enhanced 22:1 synthesis. A NIR spectroscopic calibration for 22:1 was developed for single seeds, and the calibration was used to select, in a nondestructive manner, F-2 seeds high in 22:1. Selected F-2 seeds were sown in the field and F-3 seeds were harvested. The results of the FA analysis showed recombinant genotypes with increased total monounsaturated FA (22:1 + 20:1 + 18:1) of up to 89% and decreased PUFA (<8%) and saturated FA content (<3.5%). There was no significant difference in 22:1 content, but a 3 to 5% increase in 20:1 content was observed in comparison to the HEAR parental cv. Maplus. Results were confirmed following cultivation of selected plant material a second year in the field. The present study revealed that there are other biochemical limitations than the pool of available oleoyl-CoA that restrict FA elongation to 22:1 in rapeseed. The generated high 22:1 plant material with an increased 18:1 content may be useful in further studies to identify these limitations.