Diversity in seed oil content and fatty acid composition in Acer species with potential as sources of nervonic acid

Nervonic acid (NA, cis-15-tetracosenoic acid) is a very long-chain monounsaturated fatty acid that has been shown to be a core component of nerve fibers and nerve cells. It can be used to treat and prevent many neurological diseases. At present, commercially available NA is mainly derived from Acer truncatum seeds, which contain about 5%–6% NA in their seed oil. The aim of this study were to identify and analyze NA-containing Acer species that could be used as NA resource plants. For this purpose, 46 Acer species seeds were collected in China and in some or all of the seed oils from these species 15 fatty acids were detected, including linoleic acid, oleic acid (C18:1(Δ9), C18:1(Δ11)), erucic acid, palmitic acid, NA, linolenic acid (C18:3(Δ6,9,12), C18:3(Δ9,12,15)), eicosenoic acid (C20:1(Δ11), C20:1(Δ13)), stearic acid, behenic acid, tetracosanoic acid, arachidic acid, and docosadienoic acid. Nervonic acid was detected in all samples, but the content was highly variable among species. NA content over 9% was detected in eleven species, of which Acer elegantulum had the highest levels (13.90%). The seed oil content, seed weight, and fatty acid profiles varied among species, but the comprehensive evaluation value (W) showed that A. coriaceifolium could be a new potential NA resources plant. The results also showed that NA was significantly negatively correlated with palmitic acid, oleic acid, and eicosenoic acid, but positively correlated with eicosadienoic acid, behenic acid, erucic acid, and tetracosanoic acid, which indicate the probable pathway for NA biosynthesis in Acer plants. This study has identified Acer species that may serve as NA resources and will help guide subsequent species breeding programs.