Euonymus maximowiczianus aril-derived long-term suspension-cultured cells: Light and methyl jasmonate impact in the anthocyanin and VLCFA accumulation

The genus Euonymus (L.) consists of shrubs and woody plants, distributed mainly in the Northern Hemisphere. Several hundred of secondary metabolites have been isolated from Euonymus spp. In addition, fatty oil was found in the fruits of some Euonymus spp., which accumulates not only in the seeds but also in the arils. This study presents the research of unique over ten-year-old suspension cell cultures of the endemic plant Euonymus maximoviczianus Prokh., obtained from the aril tissue of unripe capsules. The suspension cells retain the ability to form oil droplets containing neutral lipids. Both cells growing in the dark (Em-D culture) and cells growing in the light (Em-L culture) can synthesize very-long-chain fatty acids (VLCFAs) as well as cyanidin-3-O-hexoside, delphinidin-3-O-hexoside, and peonidin-3-O-hexoside. Here, we researched the VLCFA and anthocyanin accumulation dynamics during subcultivation, as well as the influence of methyl jasmonate (MeJA) and light on these processes. In the darkness, the formation of VLCFAs was more intense, while the biosynthesis of anthocyanins was significantly activated in the light. In Em-L cells, more than 76% of anthocyanins were represented by cyanidin-3-O-hexoside, and in Em-D cells delphinidin-3-O-hexoside was more actively synthesized (45%). MeJA substantially enhanced the accumulation of anthocyanins (especially in the light) and, surprisingly, the formation of VLCFAs in both Em-L and Em-D cell cultures. The possible competition between the biosynthetic pathways of VLCFAs and anthocyanins is discussed in connection with the commonality of the cytosolic pool of their precursor, malonyl-CoA.