Promising Novel Method of Acetylation Modification for Regulating Fatty Acid Metabolism in Brassica napus L.

Simple Summary The quality of rapeseed (Brassica napus) oil depends mainly on the degree of hydrocarbon chain saturation of fatty acids. In previous studies, seeds of the B. napus near-isogenic lines were used as raw materials by iTRAQ analysis at 20-35 days after pollination, and three differential proteins related to oleic acid metabolisms were found to be related to acetylation modification. Thus, we analyzed lysine acetylation using the same raw materials. The function of the corresponding genes of fatty acid metabolisms-related differential proteins was verified by identifying the overexpression of BnACP3(63K), BnACP3(63R), and BnACP3(63) in Arabidopsis thaliana. The results show that the acetylation modification of BnaACP3 may have a selective effect on oleic acid and slow down the conversion of oleic acid to linoleic acid. This is the first report of oleic acid synthesis regulation by acetylation. In this study, lysine acetylation analysis was conducted using two Brassica napus near-isogenic lines, HOCR and LOCR, containing high and low oleic acid contents, respectively, to explore this relationship. Proteins showing differences in quantitative information between the B. napus lines were identified in lysine acetylation analysis, and KEGG pathways were analyzed, yielding 45 enriched proteins, most of which are involved in carbon fixation in photosynthetic organisms, photosynthesis, ascorbate and aldarate metabolism, and glycolysis. Potential key genes related to fatty acid metabolisms were determined. To further explore the effect of acetylation modification on fatty acid metabolisms, the acyl-ACP3 related gene BnaACP3(63K) was cloned, and a base mutation at No.63 was changed via overlapping primer PCR method. This study is the first to demonstrate that acetylation modification can regulate oleic acid metabolisms, which provides a promising approach for the study of the molecular mechanism of oleic acid in rapeseed.