Investigation of γ‐Linolenic Acid and Stearidonic Acid Biosynthesis During a Life Cycle of Borago officinalis L.

Abstract

This study investigated the levels of c-linolenic (GLA, 18:3n-6) and stearidonic acid (SDA, in various parts of the borage plant (Borago officinalis L.) to elucidate D6-desaturase activity. Lipid class and fatty acid (FA) composition during germination of the seeds and FA composition of various borage parts were determined as well as FA compositions of neutral lipids (NL), polar lipids (PL), glycolipids (GL) and monogalactosyl diacylglycerols (MGDG) of borage leaves. When seeds were germinated for 12 days in the dark then exposed to light for 8 h, an overall decrease in oil content was seen with a significant increase in PL from 0.2 to 39.1%. An increase in SDA (from 0.2 to 0.6 g/100 g oil) indicated minor FA synthesis during germination and therefore, D6-desaturase activity with the most marked increase after light exposure. The FA compositions of developing and mature seeds were similar, suggesting oil/FA synthesis takes place at the initial stage of seed development. Among all the borage parts, the leaves had the highest amounts of a-linolenic acid (ALA, 18:3n-3) (36.2%), indicating D15-desaturase activity, and SDA (25.2%), indicating D6-desaturase activity. In leaves, the GL and especially, MGDG fractions had the highest amounts of SDA (31.8 and 39.8%, respectively), indicating that D6-desaturase is most active in chloroplasts. Leaves and developing seeds appear to be the major sources of D6-desaturase in borage, associated with different organelles in the different tissues.

Micropropagation and Quantification of Bioactive Compounds in Mertensia maritima (L.) Gray

“…The high level of GLA is found usually in seed oils of several plant species. It is also found in various organs such as leaves, flowers, stems and roots of some plant species [43,44,45,46,47]. However, the synthesis and accumulation of GLA in organs largely depend on plant species, genotype, growth stage, and environmental factors.…”

“…In the present study, a considerable level of GLA was found in M. maritima . The GLA content in the leaf tissues (14.05%) of in vitro-developed shoots was also greater than that found in the leaves of Borago officinalis (2.5–6.5%), Delphinium gracile (0.033%), Epilobium hirsutum (1.4%), Epilobium lanceolatum (0.81%), Myosotis nemorosa (1.45%), Primula cortusoides (4.0%), Primula denticulata (5.9%), Primula farinosa (5.4%), Primula glaucescens (6.0%), Primula luteola (1.9%), Primula marophylla (5.7%), Primula malacoides (10.9%), Primula scotica (6.7%), Primula vulgaris (0.6%), Primula vialii (1.5%), and Scrophularia sciophila (0.3%); stems of Borago officinalis (10.1–11.5%), Cynoglossum creticum (4.07%), Scrophularia sciophila (0.7%); roots of Borago officinalis (13.7%), Cynoglossum creticum (7.16%), Echium creticum (2.9%), Primula cortusoides (1.9%), Primula denticulata (0.2%), Primula farinosa (0.1%), Primula glaucescens (0.3%), Primula luteola (0.6%), Primula marophylla (0.4%), Primula malacoides (1.4%), Primula scotica (0.2%), Primula vulgaris (0.8%), Primula vialii (0.1%), S. sciophila (0.27%); and flowers of Anchusa azurea (3.56%), and Scrophularia sciophila (0.28%) [43,44,45,46,47].…”

Changes in oil content, lipid class and fatty acid composition of the microalgaChaetoceros calcitransover different phases of batch culture

“…MGDG is a proposed substrate of the lipid synthesis enzyme Δ6‐desaturase in the terrestrial plant borage (Griffith, Brechany, Jackson, Christie, Stymne & Stobert ; Staehler et al . ). The Δ6‐desaturase is a key enzyme in the production of n‐3 LC‐PUFA in eukaryotic and vertebrate systems.…”

“…Lipid classes were separated using SPE silica columns (GracePure e silica 1000 mg/6 mL from Grace Davison Discovery Sciences, Baulkham Hills, NSW, Australia) by following the elution protocol according to Stern and Tietz (1993) with minor modifications (Staehler, Quek & Miller 2011). The columns were first conditioned with 17.5 mL chloroform before they were loaded with approximately 20 mg of oil.…”

“…The chloroplast is also an important organelle for FA/lipid synthesis and modification (Marechal, Block, Dome, Douce & Joyard 1997). MGDG is a proposed substrate of the lipid synthesis enzyme D6-desaturase in the terrestrial plant borage (Griffith, Brechany, Jackson, Christie, Stymne & Stobert 1996;Staehler et al 2011). The D6-desaturase is a key enzyme in the production of n-3 LC-PUFA in eukaryotic and vertebrate systems.…”