Single-Molecule Long-Read Sequencing of Purslane (Portulaca oleracea) and Differential Gene Expression Related with Biosynthesis of Unsaturated Fatty Acids

Abstract

This study aimed to obtain the full-length transcriptome of purslane (Portulaca oleracea); assorted plant samples were used for single-molecule real-time (SMRT) sequencing. Based on SMRT, functional annotation of transcripts, transcript factors (TFs) analysis, simple sequence repeat analysis and long non-coding RNAs (LncRNAs) prediction were accomplished. Total 15.33-GB reads were produced; with 9,350,222 subreads and the average length of subreads, 1640 bp was counted. With 99.99% accuracy, after clustering, 132,536 transcripts and 78,559 genes were detected. All unique SMART transcripts were annotated in seven functional databases. 4180 TFs (including transcript regulators) and 7289 LncRNAs were predicted. The results of RNA-seq were confirmed with qRT–PCR analysis. Illumina sequencing of leaves and roots of two purslane genotypes was carried out. Amounts of differential expression genes and related KEGG pathways were found. The expression profiles of related genes in the biosynthesis of unsaturated fatty acids pathway in leaves and roots of two genotypes of purslane were analyzed. Differential expression of genes in this pathway built the foundation of ω-3 fatty acid accumulation in different organs and genotypes of purslane. The aforementioned results provide sequence information and may be a valuable resource for whole-genome sequencing of purslane in the future.

Effects of Shading Nets on Reactive Oxygen Species Accumulation, Photosynthetic Changes, and Associated Physiochemical Attributes in Promoting Cold-Induced Damage in Camellia sinensis (L.) Kuntze

“…In addition, both ω-3 alpha-linolenic acid and ω-6 linoleic acid are unsaturated fatty acids and the unsaturation level of plants' ability is used to maintain or regulate membrane fluidity, which was positively related with plant-tolerance to abiotic stress [31]. These findings are in line with those of our previous studies, in which 94 genes were identified and participate in the pathway of biosynthesis of unsaturated fatty acids and FAD2 family genes regulated for unsaturation of fatty acid composition and played an important role in ω-3 and ω-6 fatty acid desaturase to increase stress tolerance [10]. Some plants have fatty acid desaturations that regulate chloroplast fluidity and increase tolerance mechanisms in specific cultivars.…”

“…The cellular antioxidant system, composed of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), is essential for limiting ROS generation and protecting plants against cold stressors and abiotic conditions [8]. However, it is known that linoleic and linolenic acids modulate the plant's defense mechanism against several abiotic stressors [9][10][11]. Linoleic and alpha-linolenic acid are the most important unsaturated fatty acids [10] that have been effective against a variety of disorders, including cancer [12] and cardiovascular disease [13].…”

“…However, it is known that linoleic and linolenic acids modulate the plant's defense mechanism against several abiotic stressors [9][10][11]. Linoleic and alpha-linolenic acid are the most important unsaturated fatty acids [10] that have been effective against a variety of disorders, including cancer [12] and cardiovascular disease [13].…”

Improvement of a Traditional Orphan Food Crop, Portulaca oleracea L. (Purslane) Using Genomics for Sustainable Food Security and Climate-Resilient Agriculture

“…In addition to synthesizing ω-3 fatty acids, purslane also produces ω-6-fatty acids. Du et al (2021) identified 94 genes involved in the biosynthetic pathway of unsaturated fatty acids. Three genes encoding ω-6 fatty acid desaturases viz.…”

“…The study showed that three important genes, namely, Ribosomal protein S15A (RPS15A), Ribosomal protein L2 (RPL2), and ω-6-fatty acid desaturase 2 (FAD2) were induced at higher levels following rewatering/recovery of purslane, suggesting their important roles in imparting stress tolerance. FAD2 and stearoyl-acyl-carrierprotein desaturase (SAD) are also important genes involved in ω-3 fatty acid biosynthesis, and there differential expression is reported in stem and leaves of P. oleracea (Du et al, 2021). C4/CAM switching is one of the most important mechanisms reported from purslane in response to the differences in environmental conditions.…”