Unravelling a stearidonic acid-rich triacylglycerol biosynthetic pathway in the developing seeds of Buglossoides arvensis: A transcriptomic landscape

Abstract

Buglossoides arvensis is an emerging oilseed crop that is rich in stearidonic acid (SDA) and has several potential applications in human health and nutrition. The molecular basis of SDA biosynthesis in this plant remains unknown due to lack of genomic information. To unravel key genes involved in SDA-rich triacylglycerol (TAG) biosynthesis, we performed transcriptome sequencing of pooled mRNA from five different developmental stages of B. arvensis seeds using Illumina NextSeq platform. De novo transcriptome assembly generated 102,888 clustered transcripts from 39.83 million high-quality reads. Of these, 62.1% and 55.54% of transcripts were functionally annotated using Uniprot-Viridiplantae and KOG databases, respectively. A total of 10,021 SSR-containing sequences were identified using the MISA tool. Deep mining of transcriptome assembly using in silico tools led to the identification of genes involved in fatty acid and TAG biosynthesis. Expression profiling of 17 key transcripts involved in fatty acid desaturation and TAG biosynthesis showed expression patterns specific to the development stage that positively correlated with polyunsaturated fatty acid accumulation in the developing seeds. This first comprehensive transcriptome analysis provides the basis for future research on understanding molecular mechanisms of SDA-rich TAG accumulation in B. arvensis and aids in biotechnological production of SDA in other oilseed crops.

Physico-chemical Characterization, Profiling of Total Lipids and Triacylglycerol Molecular Species of Omega-3 Fatty Acid Rich <i>B. arvensis</i> Seed Oil from India

“…Adaptation, selection and evaluation of high yielding cultivar of B. arvensis BA-26 were reported in our previous study 6 . Mature seeds of BA-26 cultivar were subject to germination by exposing them to cold stratification 4-6 for 4-7 days.…”

“…The plant produces warty seeds, which are trigonous-conical in shape and greyishbrown in color. This unique and underutilized oilseed plant has been recently exploited for its high PUFA content and also for its natural ability to synthesize and accumulate an unusual ω-3 fatty acid, namely Stearidonic acid SDA; 18:4 n-3 in its seeds 6 . Further, B. arvensis seed oil is superior in terms of SDA content to other plant sources of SDA such as black currant 2-4 SDA and echium 12-14 SDA 3 .…”

“…In India, B. arvensis grows as a weed species at higher elevations in the north temperate cold climatic conditions regions of India Pampore, Jammu and Kashmir; Latitude 34.02 N and longitude 74.93 E . Our group collected the B. arvensis mature seeds from the above native habitat, successfully adapted and also assessed their suitability for large-scale commercial cultivation in tropical regions hot climatic conditions of south India 6 .…”

Tree-Borne Edible Oilseeds as Sources of Essential Omega Fatty Acids for Human Health

“…SDA is a key precursor in the biosynthesis of those omega-3 acids that are commonly found in fish oils. While health benefits of fish oils are well-accepted, those who do not eat fish are often deprived of these benefits from their diet [84].…”

“…"Consumption of B. arvensis seed oil has been reported to increase the circulating omega-3 PUFA levels in a dose-dependent manner and associated with anti-inflammatory phenotype in healthy people." This oil needs to be consumed in the form of softgel capsule, salad dressing oil, powder or protein/cereal bars, he said, adding that it may not be an ideal cooking medium as it has low smoke point and degrades upon heating, losing its nutritional qualities [84].…”