|SINGER, STACY - University Of Alberta|
|SATINDER, GIDDA - University Of Guelph|
|MULLEN, ROBERT - University Of Guelph|
|WESELAKE, RANDALL - University Of Alberta|
|NYKIFORUK, CORY - Sembiosys Genetics|
|MOLONEY, MAURICE - Sembiosys Genetics|
Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/14/2014
Publication Date: 4/16/2014
Citation: Yurchenko, O., Singer, S.D., Satinder, G., Mullen, R.T., Weselake, R.J., Nykiforuk, C.L., Moloney, M.M. 2014. Production of a Brassica napus low-molecular mass acyl-coenzyme A-binding protein in Arabidopsis alters the acyl-coenzyme A pool and acyl composition of oil in seeds. Plant Physiology. 165(2):550-560.
Interpretive Summary: The seed oils of plants are important agricultural commodities that are used for food, feed, cooking, and biofuels. The value and end-use applications for seed oils are determined in large part by the fatty acid composition of the oil. For instance, olive oil is high in monounsaturated fatty acids, which are stable at elevated temperatures, and thus make excellent cooking oils. Linseed oil, on the other hand, is high in polyunsaturated fatty acids, which are typically unstable, which makes linseed oil a useful ingredient in formulations of coatings, resins, and wood finishing products. The basic biological processes that determine fatty acid composition in seed oils are fairly well understood, but many of the underlying molecular mechanisms remain unclear. In this manuscript, a scientist working at the ARS lab in Maricopa, AZ, in collaboration with scientists from the University of Alberta, University of Guelph, and the Canadian biotechnology company SymBioSys, identify of new type of protein from rapeseed (Brassica napus) that plays an important role in determining fatty acid composition. Notably, transgenic expression of the gene encoding this protein in the model oilseed plant Arabidopsis resulted in a significant alteration in seed oil fatty acid composition. These findings will be of great interest to those interested in the molecular mechanisms of seed oil production, particularly those scientists interested in utilizing biotechnology approaches for seed oil modification.
Technical Abstract: Low-molecular mass (10 kD) cytosolic acyl-coenzyme A-binding protein (ACBP) has a substantial influence over fatty acid (FA) composition in oilseeds, possibly via an effect on the partitioning of acyl groups between elongation and desaturation pathways. Previously, we demonstrated that the expression of a Brassica napus ACBP (BnACBP) complementary DNA in the developing seeds of Arabidopsis (Arabidopsis thaliana) resulted in increased levels of polyunsaturated FAs at the expense of eicosenoic acid (20:1cisD11) and saturated FAs in seed oil. In this study, we investigated whether alterations in the FA composition of seed oil at maturity were correlated with changes in the acyl-coenzyme A (CoA) pool in developing seeds of transgenic Arabidopsis expressing BnACBP. Our results indicated that both the acyl-CoA pool and seed oil of transgenic Arabidopsis lines expressing cytosolic BnACBP exhibited relative increases in linoleic acid (18:2cisD9,12; 17.9%–44.4% and 7%–13.2%, respectively) and decreases in 20:1cisD11 (38.7%–60.7% and 13.8%–16.3%, respectively). However, alterations in the FA composition of the acyl- CoA pool did not always correlate with those seen in the seed oil. In addition, we found that targeting of BnACBP to the endoplasmic reticulum resulted in FA compositional changes that were similar to those seen in lines expressing cytosolic BnACBP, with the most prominent exception being a relative reduction in a-linolenic acid (18:3cisD9,12,15) in both the acyl-CoA pool and seed oil of the former (48.4%–48.9% and 5.3%–10.4%, respectively). Overall, these data support the role of ACBP in acyl trafficking in developing seeds and validate its use as a biotechnological tool for modifying the FA composition of seed oil.