Engineering the Staple Oil Crop Brassica napus Enriched with α-Linolenic Acid Using the Perilla FAD2-FAD3 Fusion Gene

Genetic variations in FAD3 and its influence on agronomic traits and fatty acid composition in perilla germplasm

In this study, we explored the relationship between agronomic characteristics and fatty acid composition in perilla germplasm and examined the potential effects of genetic variations in the FAD3 gene on these traits. Our analysis involved correlation, principal component analysis (PCA), hierarchical clustering, and path analysis. We discovered the days to flowering (DTF), days to maturing (DTM) number of branches (NB), and stearic acid (SA) content were positively correlated with each other. Conversely, oleic acid (OA), linoleic acid (LA), and alpha-linolenic acid (ALA) showed negative correlations among themselves. We observed significant differences in agronomic traits and fatty acid composition based on the color of the perilla seed hull, indicating the influence of genetic factors on these traits. A single nucleotide polymorphism (SNP) variation at the 182 bp position in the FAD3 gene, characterized by a homozygous G base, was significantly associated with a decrease in LA proportion. This is in line with the known biochemical role of FAD3 in fatty acid desaturation. Interestingly, this SNP was also correlated with an increase in NB, suggesting that FAD3 may have pleiotropic effects on both agronomic traits and fatty acid composition. However, SNPs at the 596 bp and 599 bp positions in the FAD3 gene did not show clear patterns, suggesting potential influences from other genetic or environmental factors. These findings offer valuable insights into the genetic and phenotypic interactions in perilla, highlighting the importance of FAD3 variation. This knowledge can aid in the development of targeted breeding and selection strategies for perilla cultivars, optimizing both agronomic performance and nutritional quality. Further research is required to clarify the precise mechanisms of FAD3 and its impact on perilla traits.

Bioengineering of long-chain polyunsaturated fatty acids in oilseed crops

Long-chain polyunsaturated fatty acids (LC-PUFAs), especially very long-chain polyunsaturated fatty acids (VLC-PUFAs), are highly beneficial to human health including brain development, cardiovascular health and the immune system. Plant-derived edible oils serve as crucial dietary sources of PUFAs for humans. However, oilseed crops such as soybean, peanut, rapeseed, sesame and flax, generally contain insufficient content of LC-PUFAs and do not naturally produce VLC-PUFAs. This review discusses PUFA biosynthesis, current efforts on LC-PUFA bioengineering in oilseed crops, comparing the advantages of different genetic engineering strategies and highlights the bottlenecks encountered in this field. Combination of high-efficient enzymes from various species has enabled the improvement of LC-PUFAs and slight production of VLC-PUFAs, though under risk of generational instability. These and future intelligently designed enzymes with multidisciplinary approaches in molecular biology, biochemistry and plant physiology can be crucial in developing oilseed crops that meet the growing demand for LC-PUFAs.

Genome-wide characterization of FAD gene family in Xanthoceras sorbifolium Bunge and germplasm assessment

Fatty acid desaturases (FADs) play a pivotal role in the accumulation of oils in plant seeds. To elucidate the role of FADs in oil accumulation in the seeds of Xanthoceras sorbifolium, this study employed bioinformatics analysis methods to identify and analyze the FAD gene family. A total of 25 XsFAD genes were unevenly distributed across 11 chromosomes. Systematic phylogenetic analysis revealed that the XsFAD gene family is divided into three branches, with each branch exhibiting similar gene structures. The regulatory elements within the XsFAD gene promoter indicate that XsFAD genes are regulated by multiple factors. Quantitative real-time polymerase chain reaction (qRT-PCR) validation revealed a positive correlation between the expression levels of XsFAD genes and the oil content of X. sorbifolium. By conducting phenotypic measurements of the X. sorbifolium fruit and seeds, as well as quantitative analysis of the XsFAD gene expression, it has been preliminarily identified that the Liudong-5 variety may poseess the potential to be developed into a high-yield oil-producing variety, which may be related to the habitat of the X. sorbifolium germplasm and requires further investagation. In summary, this study provides a foundational understanding of the FAD gene family of X. sorbifolium, and the research outcomes will contribute to the theoretical basis for the selection of high-yielding oil varieties of X. sorbifolium in the Xinjiang region, as well as further genetic breeding and cultivation system studies.

PuERF008-PuFAD2 module regulates aroma formation via the fatty acid pathway in response to calcium signaling in 'Nanguo' pear

Calcium acts as a secondary messenger in plants and is essential for plant growth and development. However, studies on the pathway of aroma synthesis in 'Nanguo' pear (Pyrus ussriensis Maxim.) are scarce. In this study, a bioinformatics analysis of transcriptomic data from calcium-treated 'Nanguo' pear was performed, which identified two fatty acid desaturases, PuFAD2 and PuFAD3, and eight AP2/ERF transcription factors, all exhibiting the same expression patterns. Transient expression experiments showed overexpression of PuFAD2 and PuFAD3 significantly increased the levels of aromatic substrates linoleic acid, hexanal, linolenic acid, and (E)-2-hexenal, but RNAi (RNA interference) had the opposite expression. Promoter sequences analysis revealed that PuFAD2 and PuFAD3 have ERE (estrogen response element) motifs on their promoters. The strongest activation of PuFAD2 by PuERF008 was verified using a dual-luciferase reporting system. Additionally, yeast one-hybrid and electrophoretic mobility shift assays revealed PuERF008 could active PuFAD2. Transient overexpression and RNAi analyses of PuERF008 showed a strong correlation with the expression of PuFAD2. This study provides insights into the process of aroma biosynthesis in 'Nanguo' pear and offers a theoretical basis for elucidating the role of calcium signaling in aroma synthesis.

Comparative Transcriptomics Uncovers Upstream Factors Regulating BnFAD3 Expression and Affecting Linolenic Acid Biosynthesis in Yellow-Seeded Rapeseed (Brassica napus L.)

α-Linolenic acid (ALA) is an important nutrient component in rapeseed oil, and rapeseed breeders want to either restrain or enhance the function of fatty acid desaturases (FADs) in the ALA biosynthesis pathway. To determine the reason for the upregulation of rapeseed BnFAD genes in two high-ALA accessions, R8Q10 and YH25005, we compared their transcriptome profiles in the seed at 24 days after pollination (DAP) with those of two low-ALA lines, A28 and SW. The expression levels of twenty-eight important genes in the seed samples at 20, 27, and 34 DAP were also investigated using an RT-qPCR. The expression levels of genes involved in flavonoid and proanthocyanidin synthesis, including BnCHS, BnCHI, BnDFR, BnFLS1, BnLDOX, BnBAN, BnTT10, and BnTT12 and genes encoding the transcription factors BnTT1, BnTT2, BnTT8, and BnTT16 were lower in R8Q10 and YH25005 than in A28 and SW. The expression levels of genes encoding master transcription factors in embryo development, such as BnLEC1, BnABI3, BnFUS3, BnL1L, BnAREB3, and BnbZIP67, were elevated significantly in the two high-ALA accessions. Combined with previous results in the Arabidopsis and rapeseed literature, we speculated that the yellow-seededness genes could elevate the activity of BnLEC1, BnABI3, BnFUS3, and BnbZIP67, etc., by reducing the expression levels of several transparent testa homologs, resulting in BnFAD3 and BnFAD7 upregulation and the acceleration of ALA synthesis. Yellow-seededness is a favorable factor to promote ALA synthesis in the two high-ALA accessions with the yellow-seeded trait. These findings provide initial insights into the transcriptomic differences between high-/low-ALA germplasms and a theoretic basis for seed quality breeding.

A metabolomics discrimination-based strategy for screening the antithrombin active markers of perilla seeds: A natural oil crop

Natural crops oil with high nutritional value has gradually attracted attention. Perilla seeds are regarded as a source of functional edible oil in America, Asia and European countries due to its abundant nutrients. In this research, samples were extracted by different polarity solvents and evaluated their thrombin inhibition activities in vitro. Metabolomics combined with chemometrics revealed the antithrombin active markers of perilla seeds. The enzyme kinetics and molecular docking results were useful in clarifying their inhibition of thrombin. The orthogonal experimental design was applied to optimize the extraction process of six antithrombin active markers from perilla seeds. The results showed that rosmarinic acid, luteolin, luteolin-7-O-glucoside, α-linolenic acid, linoleic acid, and oleic acid were screened out as functional and active markers. Besides, perilla seeds as a natural oil crop had the potential of antithrombin. It can also be applied in the food field because of its nutraceutical functions. Metabolomics combined with chemometrics will facilitate the discovery of functional, active markers in perilla seeds, which is conducive to accurate quality control.