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The regulation of microsomal (e.g., FAD2) and plastidial (e.g., FAD6) oleate desaturases by cold, heat and salt stress were investigated. Gene expression levels and fatty acid compositions were determined in the roots, stems and leaves of safflower following stress treatments. A safflower plastidial oleate desaturase gene, CtFAD6, was cloned, and oleic acid desaturation was confirmed in Synechococcus sp. strain PCC7942. The results showed that temperature regulated oleate desaturation at the transcriptional level, and this regulation pattern was tissue-specific. CtFAD2-1, CtFAD2-2 and CtFAD6 were significantly induced under cold and heat stress in young leaves, and CtFAD2-2 and CtFAD6 were slightly induced in young stems. In contrast, CtFAD2-1, CtFAD2-11 and CtFAD2-10 were sensitive to salt stress in all safflower tissues (roots, stem and leaves). CtFAD6 was insensitive to salt and was slightly induced in leaves only. [ABSTRACT FROM AUTHOR]

The genomes of the best‐studied pseudomonads, Pseudomonas aeruginosa and Pseudomonas putida, which share 85% of the predicted coding regions, contain a fabA fabB operon (demonstrated in P. aeruginosa, putative in P. putida). The enzymes encoded by the fabA and fabB genes catalyze the introduction of a double bond into a 10‐carbon precursor which is elongated to the 16:1Δ9 and 18:1Δ11 unsaturated fatty acyl chains required for functional membrane phospholipids. A detailed analysis of transcription of the P. putida fabA fabB gene cluster showed that fabA and fabB constitute an operon and disclosed an unexpected and essential fabB promoter located within the fabA coding sequence. Inactivation of the fabA fabB operon fails to halt the growth of P. aeruginosa PAO1 but blocks growth of P. putida F1 unless an exogenous unsaturated fatty acid is provided. We report that the asymmetry between these two species is due to the P. aeruginosa PAO1 desA gene which encodes a fatty acid desaturase that introduces double bonds into the 16‐carbon acyl chains of membrane phospholipids. Although P. putida F1 encodes a putative DesA homolog that is 84% identical to the P. aeruginosa PAO1, the protein fails to provide sufficient unsaturated fatty acid synthesis for growth when the FabA FabB pathway is inactivated. We report that the P. putida F1 DesA homolog can functionally replace the P. aeruginosa DesA. Hence, the defect in P. putida F1 desaturation is not due to a defective P. putida F1 DesA protein but probably to a weakly active component of the electron transfer process. [ABSTRACT FROM AUTHOR]

Walnut (Juglans regia L.) is an important woody oilseed tree species due to its commercial value. However, the regulation mechanism of walnut oil accumulation is still poorly understood, which restricted the breeding and genetic improvement of high-quality oil-bearing walnuts. In order to explore the metabolic mechanism that regulates the synthesis of walnut oil, we used transcriptome sequencing technology and metabolome technology to comprehensively analyze the key genes and metabolites involved in oil synthesis of the walnut embryo at 60, 90, and 120 days after pollination (DAP). The results showed that the oil and protein contents increased gradually during fruit development, comprising 69.61% and 18.32% of the fruit, respectively, during ripening. Conversely, the contents of soluble sugar and starch decreased gradually during fruit development, comprising 2.14% and 0.84%, respectively, during ripening. Transcriptome sequencing generated 40,631 unigenes across 9 cDNA libraries. We identified 51 and 25 candidate unigenes related to the biosynthesis of fatty acid and the biosynthesis of triacylglycerol (TAG), respectively. The expression levels of the genes encoding Acetyl-CoA carboxylase (ACCase), long-chain acyl-CoA synthetases (LACS), 3-oxoacyl-ACP synthase II (KASII), and glycerol-3-phosphate acyl transfer (GPAT) were upregulated at 60 DAP relative to the levels at 90 and 120 DAP, while the stearoyl-ACP-desaturase (SAD) and fatty acid desaturase 2 (FAD2) genes were highly abundantly expressed during all walnut developmental periods. We found that ABSCISIC ACID INSENSEITIVE3 (ABI3), WRINKLEDl (WRI1), LEAFY COTYLEDON1 (LEC1), and FUSCA3 (FUS3) may be key transcription factors involved in lipid synthesis. Additionally, the metabolomics analysis detected 706 metabolites derived from 18 samples, among which, 4 are implicated in the TAG synthesis, 2 in the glycolysis pathway, and 5 in the tricarboxylic acid cycle (TCA cycle) pathway. The combined analysis of the related genes and metabolites in TAG synthesis showed that phospholipid:diacylglycerol acyltransferase (PDAT) genes were highly abundantly expressed across walnut fruit developmental periods, and their downstream metabolite TAG gradually accumulated with the progression of fruit development. The FAD2 gene showed consistently higher expression during fruit development, and its downstream metabolites 18:2-PC and 18:3-PC gradually accumulated. The ACCase, LACS, SAD, FAD2, and PDAT genes may be crucial genes required for walnut oil synthesis. Our data will enrich public databases and provide new insights into functional genes related to lipid metabolism in walnut. [ABSTRACT FROM AUTHOR]

Embryos contain a large number of lipid droplets, and lipid metabolism is gradually activated during embryonic development to provide energy. However, the regulatory mechanisms remain to be investigated. Stearoyl-CoA desaturase 1 (Scd1) is a fatty acid desaturase gene that is mainly involved in intracellular monounsaturated fatty acid production, which takes part in many physiological processes. Analysis of transcripts at key stages of embryo development revealed that Scd1 was important and expressed at an increased level during the cleavage and blastocyst stages. Knockout Scd1 gene by CRISPR/Cas9 from zygotes revealed a decrease in lipid droplets (LDs) and damage in the inner cell mass (ICM) formation of blastocyst. Comparative analysis of normal and knockout embryo transcripts showed a suppression of ribosome protein (RPs) genes, leading to the arrest of ribosome biogenesis at the 2-cell stage. Notably, the P53-related pathway was further activated at the blastocyst stage, which eventually caused embryonic development arrest and apoptosis. In summary, Scd1 helps in providing energy for embryonic development by regulating intra-embryonic lipid droplet formation. Moreover, deficiency activates the RPs-Mdm2-P53 pathway due to ribosomal stress and ultimately leads to embryonic development arrest. The present results suggested that Scd1 gene is essential to maintain healthy development of embryos by regulating energy support. [ABSTRACT FROM AUTHOR]

Background: CRISPR/Cas9 is the most powerful and versatile genome-editing tool that permits multiplexed-targeted gene modifications for the genetic enhancement of oil palm. Multiplex genome-editing has recently been developed for modifying multiple loci in a gene or multiple genes in a genome with high precision. This study focuses on the development of high-oleic oil palm, the primary target trait for healthy low-saturated oil. To achieve this, the fatty acid desaturase 2 (FAD2) and palmitoyl-acyl carrier protein thioesterase (PAT) genes, both of which are associated with fatty acid metabolism biosynthesis pathways in oil palm, need to be knocked out. The knockout of FAD2 and PAT leads to an accumulation of oleic acid content in oil palms. Results: A total of four single-guide RNAs (sgRNAs) were designed in silico based on the genomic sequences of EgFAD2 and EgPAT. Using robust plant CRISPR/Cas9 vector technology, multiple sgRNA expression cassettes were efficiently constructed into a single-binary CRISPR/Cas9 vector to edit the EgFAD2 and EgPAT genes. Each of the constructed transformation vectors was then delivered into oil palm embryogenic calli using the biolistic, Agrobacterium-mediated, and PEG-mediated protoplast transformation methods. Sequence analysis of PCR products from 15 samples confirmed that mutations were introduced at four target sites of the oil palm EgFAD2 and EgPAT genes. Single- and double-knockout mutants of both genes were generated, with large and small deletions within the targeted regions. Mutations found at EgFAD2 and EgPAT target sites indicate that the Cas9/sgRNA genome-editing system effectively knocked out both genes in oil palm. Conclusion: This technology is the first in oil palm to use CRISPR/Cas9 genome-editing to target high-oleic-associated genes. These findings showed that multiplex genome-editing in oil palm could be achieved using multiple sgRNAs. Targeted mutations detected establish that the CRISPR/Cas9 technology offers a great potential for oil palm. [ABSTRACT FROM AUTHOR]

Soybean with enriched nutrients has emerged as a prominent source of edible oil and protein. In the present study, a meta-analysis was performed by integrating quantitative trait loci (QTLs) information, region-specific association and transcriptomic analysis. Analysis of about a thousand QTLs previously identified in soybean helped to pinpoint 14 meta-QTLs for oil and 16 meta-QTLs for protein content. Similarly, region-specific association analysis using whole genome re-sequenced data was performed for the most promising meta-QTL on chromosomes 6 and 20. Only 94 out of 468 genes related to fatty acid and protein metabolic pathways identified within the meta-QTL region were found to be expressed in seeds. Allele mining and haplotyping of these selected genes were performed using whole genome resequencing data. Interestingly, a significant haplotypic association of some genes with oil and protein content was observed, for instance, in the case of FAD2-1B gene, an average seed oil content of 20.22% for haplotype 1 compared to 15.52% for haplotype 5 was observed. In addition, the mutation S86F in the FAD2-1B gene produces a destabilizing effect of (ΔΔG Stability) −0.31 kcal/mol. Transcriptomic analysis revealed the tissue-specific expression of candidate genes. Based on their higher expression in seed developmental stages, genes such as sugar transporter, fatty acid desaturase (FAD), lipid transporter, major facilitator protein and amino acid transporter can be targeted for functional validation. The approach and information generated in the present study will be helpful in the map-based cloning of regulatory genes, as well as for marker-assisted breeding in soybean. [ABSTRACT FROM AUTHOR]

Psychrophilic yeasts are distributed widely on Earth and have developed adaptation strategies to overcome the effect of low temperatures. They can adapt to low temperatures better than bacteriophyta. However, to date, their whole-genome sequences have been limited to the analysis of single strains of psychrophilic yeasts, which cannot be used to reveal their possible psychrophilic mechanisms to adapt to low temperatures accurately and comprehensively. This study aimed to compare different sources of psychrophilic yeasts at the genomic level and investigate their cold-adaptability mechanisms in a comprehensive manner. Nine genomes of known psychrophilic yeasts and three representative genomes of mesophilic yeasts were collected and annotated. Comparative genomic analysis was performed to compare the differences in their signaling pathways, metabolic regulations, evolution, and psychrophilic genes. The results showed that fatty acid desaturase coding genes are universal and diverse in psychophilic yeasts, and different numbers of these genes exist (delta 6, delta 9, delta 12, and delta 15) in the genomes of various psychrophilic yeasts. Therefore, they can synthesize polyunsaturated fatty acids (PUFAs) in a variety of ways and may be able to enhance the fluidity of cell membranes at low temperatures by synthesizing C18:3 or C18:4 PUFAs, thereby ensuring their ability to adapt to low-temperature environments. However, mesophilic yeasts have lost most of these genes. In this study, psychrophilic yeasts could adapt to low temperatures primarily by synthesizing PUFAs and diverse antifreeze proteins. A comparison of more psychrophilic yeasts' genomes will be useful for the study of their psychrophilic mechanisms, given the presence of additional potential psychrophilic-related genes in the genomes of psychrophilic yeasts. This study provides a reference for the study of the psychrophilic mechanisms of psychrophilic yeasts. [ABSTRACT FROM AUTHOR]

Chickpea (Cicer arietinum L.) suffers from chilling stress at the reproductive stage (<15 °C) which leads to significant yield loss. This study presents a comprehensive plant response to drought priming and its effect on chilling tolerance during the reproductive stage in two chickpea cultivars PBG1 and PBG5. Lipidome profiling (Fatty acid methyl esters analysis), metabolome profiling (GC-MS based untargeted analysis), fatty acid desaturases and antioxidative gene expression (qRT-PCR) were analyzed to monitor physiological and biochemical events after priming during flowering, podding and seed filling stages. Drought priming alleviated membrane damage and chlorophyll degradation by increasing membrane unsaturated fatty acids (18:3) along with up-regulation of various fatty acid desaturases (CaFADs) genes and antioxidative machinery during flowering and improved seed yield in PBG5. PCA, HCA, and KEGG pathway analysis of 87 identified metabolites showed that metabolites were regulated differently in both cultivars under non-primed and primed conditions. The plant response was more apparent at flowering and podding stages which coincided with chilling temperature (<15 °C). Drought priming stimulated many important genes, especially FADs , antioxidative proteins and accumulation of key metabolites (proline and TCA intermediates) required for defense especially in PBG5. This explains that plant's response to drought priming not only depends on developmental stage, and temperature regime (<15 °C) but also on the genotypic-specificity. [Display omitted] • Drought priming during the vegetative stage can improve the plant's tolerance against chilling stress. • Priming enhances membrane unsaturation and upregulates fatty acid desaturases gene expression. • Priming improves chlorophyll pigment retention and accumulation of osmolytes. • Priming induced defense, related metabolic pathways and improved reproductive functioning. • Plant response to drought priming depends upon exposure, developmental stage, and genotype. [ABSTRACT FROM AUTHOR]

A major concern for olive cultivation in many extra-Mediterranean regions is the adaptation of recently introduced cultivars to environmental conditions different from those prevailing in the original area, such as the Mediterranean basin. Some of these cultivars can easily adapt their physiological and biochemical parameters in new agro-environments, whereas others show unbalanced values of oleic acid content. The objective of this study was to evaluate the effects of the thermal regime during oil synthesis on the expression of fatty acid desaturase genes and on the unsaturated fatty acid contents at the field level. Two cultivars (Arbequina and Coratina) were included in the analysis over a wide latitudinal gradient in Argentina. The results suggest that the thermal regime exerts a regulatory effect at the transcriptional level on both OeSAD2 and OeFAD2-2 genes and that this regulation is cultivar-dependent. It was also observed that the accumulated thermal time affects gene expression and the contents of oleic and linoleic acids in cv. Arbequina more than in Coratina. The fatty acid composition of cv. Arbequina is more influenced by the temperature regime than Coratina, suggesting its greater plasticity. Overall, findings from this study may drive future strategies for olive spreading towards areas with different or extreme thermal regimes serve as guidance for the evaluation olive varietal patrimony. [ABSTRACT FROM AUTHOR]

Long-chain polyunsaturated fatty acid formation requires fatty acid desaturase (FADS), which is strongly linked to cancer progression. Nevertheless, it's unclear how FADS3 functions in head and neck squamous cell carcinoma (HNSCC). HNSCC cases were retrieved from TCGA and GEO databases, and FADS members with transcriptionally differential expression were identified. Clinical survival, tumor microenvironment (TME), and potential pathogenic mechanism in HNSCC were also investigated. These results were validated using tissue staining, flow cytometry and functional studies in HNSCC cell lines. When comparing HNSCC to normal epithelial tissues, FADS3 expression was much higher in the former. FADS3 upregulation was correlated with poor clinical outcomes. FADS3 was an independent prognostic factor for poor overall survival in HNSCC patients. KEGG, GO, and GSEA revealed that FADS3 expression correlated with several immune-related pathways and the epithelial-mesenchymal transition (EMT). Knocking down FADS3 restrained HNSCC cell proliferation, migration, invasion, and EMT. Single-cell dataset analysis showed an association between FADS3 and TME features. Further investigation revealed that FADS3high tumor was accompanied with less CD8+ T cells in situ tissue and peripheral blood. FADS3 was positively correlated with immune-related molecules and could predict the adverse efficacy of immunotherapy. Finally, we constructed a CYTOR/hsa-let-7c-5p axis regulating FADS3 expression in HNSCC progression. FADS3 may represent a target for treatment in HNSCC, which is linked to prognosis, EMT, immune infiltration, and ceRNA regulatory network of HNSCC. • FADS3 upregulation is associated with poor HNSCC patient prognosis. • In HNSCC, FADS3 promotes proliferation, migration, and invasion and induces EMT. • FADS3 reduces the CD8+ T cell infiltration in HNSCC. • Increased FADS3 is related to worse effects of immunotherapy in HNSCC patients. • We constructed a CYTOR/hsa-let-7c-5p/FADS3 axis in HNSCC. [ABSTRACT FROM AUTHOR]

Cold stress represents one of the major constraints for agricultural systems and crops productivity, inducing a wide range of negative effects. Particularly, long-term cold stress affects lipid metabolism, modifying the lipids/proteins ratio, the levels of phospholipids and glycolipids, and increasing lipids' unsaturation in bio-membranes. Glucose-6-phosphate dehydrogenase (G6PDH) reported prominent roles as NADPH suppliers in response to oxidative perturbations. Cytosolic G6PDH was suggested as the main isoform involved in cold stress response, while a down-regulation of the chloroplastic P1-G6PDH was observed. We thus investigated an Arabidopsis mutant defective for the P1-G6PDH (KO-P1) using integrated approaches to verify a possible role of this isoform in low temperature tolerance. KO-P1 genotype showed an improved tolerance to cold stress, highlighting a better photosynthetic efficiency, a reduction in stress markers content and a different regulation of genes involved in stress response. Intriguingly, the lack of P1-G6PDH induced modification in the levels of the main fatty acid and lipid species affecting the morphology of chloroplasts and mitochondria, which was restored under cold. Globally, these results indicate a priming effect induced by the absence of P1-G6PDH able to improve the tolerance to abiotic stress. Our results suggest novel and specific abilities of P1-G6PDH, highlighting its central role in different aspects of plant physiology and metabolism. • In absence of P1-G6PDH, total G6PDH activity is compensated by other isoforms. • P1-G6PDH defective genotype shows an improved tolerance to cold stress. • Chloroplast metabolism and morphology are modified by the absence of P1-G6PDH. • P1-G6PDH showed an important role in the biosynthesis of fatty acid and lipids. [ABSTRACT FROM AUTHOR]

It is becoming increasingly clear that not only unicellular, photoautotrophic eukaryotes, plants, and fungi, but also invertebrates are capable of synthesizing ω3 long-chain polyunsaturated fatty acids (LC-PUFA) de novo. However, the distribution of this anabolic capacity among different invertebrate groups and its implementation at the gene and protein level are often still unknown. This study investigated the PUFA pathways in common soil fauna, i.e. two nematode and two Collembola species. Of these, one species each (Panagrellus redivivus , Folsomia candida) was assumed to produce ω3 LC-PUFA de novo , while the others (Acrobeloides bodenheimeri , Isotoma caerulea) were supposed to be unable to do so. A highly labeled oleic acid (99 % 13C) was supplemented and the isotopic signal was used to trace its metabolic path. All species followed the main pathway of lipid biosynthesis. However, in A. bodenheimeri this terminated at arachidonic acid (ω6 PUFA), whereas the other three species continued the pathway to eicosapentaenoic acid (ω3 PUFA), including I. caerulea. For the nematode P. redivivus the identification and functional characterization of four new fatty acid desaturase (FAD) genes was performed. These genes encode the FAD activities Δ9, Δ6, and Δ5, respectively. Additionally, the Δ12 desaturase was analyzed, yet the observed activity of an ω3 FAD could not be attributed to a coding gene. In the Collembola F. candida , 11 potential first desaturases (Δ9) and 13 front-end desaturases (Δ6 or Δ5 FADs) have been found. Further sequence analysis indicates the presence of omega FADs, specifically Δ12, which are likely derived from Δ9 FADs. • For the nematode P. redivivus the functional characterization of four new fatty acid desaturases was performed. • These genes encode the FAD activities Δ9, Δ6, and Δ5, respectively. • In the Collembola F. candida , 11 proposed first and 13 front-end desaturases have been found. • Further sequence analysis indicates the presence of omega FADs, specifically Δ12. [ABSTRACT FROM AUTHOR]

Astaxanthin is a kind of carotenoids, which has strong antioxidant activity. It is widely used in food, chemical industry, medical treatment and other fields. Our previous research confirmed that carotenoids in Phaffia rhodozyma could be influenced by melatonin (MT) and sodium orthovanadate (SOV), but their metabolic regulation mechanism of astaxanthin biosynthesis was not clear. In this study, metabolic regulation mechanism of MT and SOV was explored by metabonomics and fermentation dynamics. The results showed that adding 1.54 mM SOV at 27.03 h and 7.49 mM MT at 36 h could improve the astaxanthin cell yield by 64.67 %, from 3.54 mg/g to 5.83 mg/g. SOV promoted carbon flux into astaxanthin synthesis pathway by inhibiting its activity by binding to glutamate dehydrogenase pocket and reducing the expression of arginine, glutamine and isoleucine in amino acid pathway. The regulation of MT increased the expression of fatty acid synthase, fatty acid desaturase and acetyl-CoA carboxylase in fatty acid pathway, thus increasing the accumulation of fatty acids. Fermentation dynamic kinetics showed SOV and MT effectively weakened the growth coupling limitation of carotenoid and astaxanthin synthesis, which increased the astaxanthin content by 22.52 % and 21.32 %, respectively. This study provided a theoretical basis for regulating the production of astaxanthin in Phaffia rhodozyma. [Display omitted] • The cell yield of astaxanthin was increased by 64.67 %. • SOV affected the catalytic activity of GLDH and the metabolic pathway of amino acids. • The regulation of MT increased the expression in fatty acid pathway. • The fermentation kinetics was combined with molecular docking and metabonomics. [ABSTRACT FROM AUTHOR]

Ginkgo (Ginkgo biloba L.) is widely cultivated for leaves containing flavonoids and ginkgolides with various bioactivities, achieving global sales of preparations exceeding $10 billion. Improving the secondary metabolites contents in Ginkgo leaves holds significant importance for health and socioeconomic aspects. In natural settings, moderate stress boosts the biosynthesis and accumulation of secondary metabolites. However, controlling stress during growth to improve secondary metabolites contents in Ginkgo leaves is impractical due to the multiple, complex, and uncontrollable field conditions. To address the trouble, this study employed exogenous hydrogen peroxide (H 2 O 2), an essential substance that stress affects secondary metabolism, at concentrations of 20, 200, and 2000 mmol·L−1, applied to pre- and post-harvest fresh Ginkgo leaves. Parameters including reactive oxygen species, antioxidant enzymes, osmolytes, flavonoids, and ginkgolides were measured, and metabolomics and bioinformatics were conducted to analyze metabolites and fatty acid desaturase (FAD). As a result, superoxide radical, H 2 O 2 , and malondialdehyde significantly increased after treatment with exogenous H 2 O 2 , and antioxidant enzymes such as superoxide dismutase, catalase, and peroxidase, as well as osmolytes like proline, soluble protein, and soluble sugar, also notably increased. Concurrently, GbFAD was influenced, including stress-responsive elements, gene expression patterns, protein secondary structure, etc., leading to a significant upregulation of lipids and lipid-like molecules, which helped maintain cell membrane structure and function, facilitating secondary metabolism. Consequently, the secondary metabolites contents in post-harvest fresh Ginkgo leaves appreciably improved, particularly at 200 mmol·L−1, with quercetin, kaempferol, isorhamnetin, ginkgolide A, ginkgolide B, ginkgolide C, and bilobalide increasing by 68.01 %, 26.86 %, 42.99 %, 29.09 %, 39.60 %, 45.83 %, and 51.25 %, respectively. Exogenous H 2 O 2 induces physiological responses in the post-harvest fresh Ginkgo leaves similar to those observed under pre-harvest stress, thereby improving flavonoids and ginkgolides contents. This groundbreaking discovery that exogenous H 2 O 2 can induce stress in post-harvest fresh Ginkgo leaves to increase secondary metabolites contents on an industrial scale not only further advances the Ginkgo-related pharmaceutical industry but also provides a novel approach and perspective for improving secondary metabolites contents in other medicinal crops during post-harvest processing. [Display omitted] • Exogenous H 2 O 2 induces stress-like physiological responses in post-harvest fresh Ginkgo leaves. • Exploring intricate mechanisms of secondary metabolite biosynthesis in post-harvest fresh Ginkgo leaves through multifaceted analysis. • Exogenous H 2 O 2 improves the main secondary metabolites contents in post-harvest fresh Ginkgo leaves, with increases up to 68.01 %. • The discovery benefits the Ginkgo pharmaceutical industry and provides a method to improve secondary metabolites contents in other medicinal crops. [ABSTRACT FROM AUTHOR]

Stearoyl-CoA desaturase-1 (SCD1) is a pivotal enzyme in lipogenesis, which catalyzes the synthesis of monounsaturated fatty acids (MUFA) from saturated fatty acids, whose ablation downregulates lipid synthesis, preventing steatosis and obesity. Yet deletion of SCD1 promotes hepatic inflammation and endoplasmic reticulum stress, raising the question of whether hepatic SCD1 deficiency promotes further liver damage, including fibrosis. To delineate whether SCD1 deficiency predisposes the liver to fibrosis, cirrhosis, and hepatocellular carcinoma (HCC), we employed in vivo SCD1 deficient global and liver-specific mouse models fed a high carbohydrate low-fat diet and in vitro established AML12 mouse cells. The absence of liver SCD1 remarkably increased the saturation of liver lipid species, as indicated by lipidomic analysis, and led to hepatic fibrosis. Consistently, SCD1 deficiency promoted hepatic gene expression related to fibrosis, cirrhosis, and HCC. Deletion of SCD1 increased the circulating levels of Osteopontin, known to be increased in fibrosis, and alpha-fetoprotein, often used as an early marker and a prognostic marker for patients with HCC. De novo lipogenesis or dietary supplementation of oleate, an SCD1-generated MUFA, restored the gene expression related to fibrosis, cirrhosis, and HCC. Although SCD1 deficient mice are protected against obesity and fatty liver, our results show that MUFA deprivation results in liver injury, including fibrosis, thus providing novel insights between MUFA insufficiency and pathways leading to fibrosis, cirrhosis, and HCC under lean non-steatotic conditions. [Display omitted] • SCD1 deficiency remarkably increases saturated hepatic lipid species. • SCD1 deficiency increases the expression of genes related to fibrosis, cirrhosis, and HCC. • SCD1 deficiency promotes fibrosis in the absence of steatosis and obesity under a high carbohydrate low fat diet. • Oleate, a product of SCD1, ameliorates the gene expression related to fibrosis, cirrhosis, and hepatocellular carcinoma. [ABSTRACT FROM AUTHOR]

Fatty Acid Desaturase 2 (FAD2), a key enzyme in the fatty acid biosynthesis pathway, is involved in the desaturation and conversion of oleic acid to linoleic acid. Therefore, it plays a crucial role in oleic/linoleic acid ratio and the quality of olive oil. DNA sequencing of 19 FAD2 genes from a set of olive oil varieties revealed several single-nucleotide polymorphisms (SNPs) and highlighted associations between some of the SNPs and saturated fatty acids contents. This was further confirmed by SNP-interaction and machine learning approach. Haplotype diversity analysis led to the discovery of three highly polymorphic SNPs and four haplotypes harboring differential oleic/linoleic acid ratios. Moreover, a combination of molecular modeling and docking experiments allowed a deeper and better understanding of the structure–function relationship of the FAD2 enzyme. Sequence patterns and variations involved in the regulation of the FAD2 activity were also identified. Furthermore, S82C and H213N substitutions in OeFAD2 make the Oueslati variety more interesting in terms of fatty acid profile and oleic acid level.

The purpose of this study was to assess long chain polyunsaturated fatty acid (LCPUFA) status in relation to socio-behavioral outcomes in children with Attention Deficit/Hyperactivity Disorder (AD/HD). In a case-control design, plasma phospholipid fatty acid content was assessed in children aged 5–12 years with AD/HD and in typically functioning children. Dietary intakes of LCPUFAs arachidonic acid (AA; 20:4n6) and docosahexaenoic acid (DHA; 22:6n3) were quantified using a four-day food record, polymorphisms were determined in FADS1 and FADS2, and socio-behavioral outcomes were assessed using the Conners 3 Parent Rating Scales in a cross section of children with AD/HD. Compared to typically functioning children, plasma AA and DHA were 40% lower in children with AD/HD. Median intake of AA, but not DHA, was higher in children with AD/HD compared to typically functioning children. Polymorphisms in FADS1 (rs174546) and FADS2 (174575) were associated with higher plasma linoleic acid (LA; 18:2n6) level. Plasma DHA level was inversely associated with inattention score. Despite having an elevated intake of AA, children diagnosed with AD/HD have a reduction in plasma AA level which may be due in part to polymorphisms in the fatty acid desaturase (FADS) gene cluster or increased conversion to AA-derived metabolites. Increasing intake of DHA may ameliorate symptoms of inattention in AD/HD.

Fatty acid desaturases (FADs) play important roles in various metabolic and adaptive pathways in all living organisms. They represent a superfamily of oxygenases that introduce double bonds into the acyl chains of fatty acids (FAs). These enzymes are highly specific to the length of the carbon chain, position of double bonds formation, etc. The modes by which FADs "count" the position of the double bond formation may differ. In cyanobacteria, the first double bond is formed between 9th and 10th carbons (position Δ9), counting from the carboxylic end of an FA. Other FADs that produce polyunsaturated FAs may introduce double bonds counting from the carboxyl (Δ) or methyl (ω) terminus, or from a pre-existing double bond towards carboxyl or methyl terminus of an FA chain. Here, we expressed the desD gene for the Δ6-FAD from Synechocystis sp. PCC 6803 in Synechococcus elongatus PCC 7942 (which is capable of synthesizing only monoenoic FAs desaturated mainly at position Δ9) and observed the appearance of unusual monoenoic FAs desaturated at position Δ6, as well as Δ6,9 dienoic FAs. Exogenously added cis-10-heptadecenoic acid (17:1Δ10) was converted into cis-6,10-heptadecadienoic (17:2Δ6,10). These data demonstrate the ability of Δ6-FAD to introduce the first double bond into the unsaturated substrates and suggests that it "counts" from the carboxyl end, irrespective of the absence or presence of a previous double bond in an FA chain. [ABSTRACT FROM AUTHOR]

Plants use different strategies in response to environmental stress. Unsaturated fatty acids (UFAs) protect the plant against environmental stresses, especially temperature stresses, by regulating the fluidity of the cell membrane and also by scavenging reactive oxygen species (ROS) compounds. In this study, the expression changes of (Fatty Acid Desaturases) FAD2, 3 and 4 genes as well as fatty acid profile in two species Pistacia khinjuk and Pistacia atlantica were studied in response to different climatic conditions. The results show that the highest content of polyunsaturated fatty acids (PUFAs) is related to P. khinjuk species in Anjirk (AJ) region. Also, the highest content of monounsaturated fatty acids (MUFAs) can be seen in the same region in P. atlantica species. Comparing the two species, it can be observed that P. atlantica relatively contains more unsaturated fatty acids. The lowest expression of desaturase genes in the studied samples was in the Jebalbarez (JE) region. These results prove that both studied species changed the expression of desaturase genes in response to stress and finally the nutritional quality of the plant has been affected. [ABSTRACT FROM AUTHOR]

Soybean (Glycine max (L.) Merr.) oil is an important source of vegetable oil for supporting the human diet. However, the high level of polyunsaturated fatty acids in natural soybean oil renders the oil unstable and thus susceptible to the development of unpalatable flavors and trans fatty acids. Therefore, reducing the content of polyunsaturated fatty acids and increasing the content of monounsaturated fatty acids is a longstanding and important target for soybean breeding. However, soybean varieties with a high oleic acid content are rare in soybean germplasm resources, which introduces substantial difficulties in the cultivation of high-oleic-acid soybeans. In this study, CRISPR/Cas9-mediated gene-editing technology was used to create targeted knockout of the soybean fatty acid desaturase encoding genes GmFAD2-1A and GmFAD2-1B that contribute to the formation of polyunsaturated fatty acids. We obtained fad2-1a, fad2-1b, and fad2-1a/fad2-1b homozygous mutants using two sgRNAs. We found that the oleic acid content increased from 11% to 40-50% in the fad2-1a and fad2-1b mutants and to 85% in the fad2-1a/fad2-1b mutants. We also generated transgene-free double mutants that conferred higher oleic acid, and the fad2-1a/fad2-1b mutant had no adverse phenotyping compared with the wild type. Our study provided new materials for the selection and breeding of high-oleic-acid soybean varieties. [ABSTRACT FROM AUTHOR]

Obesity promotes the development of osteoarthritis (OA). It is also well‐established that obesity leads to excessive lipid deposition in nonadipose tissues, which often induces lipotoxicity. The objective of this study was to investigate changes in the levels of various lipids in mouse cartilage in the context of obesity and determine if chondrocyte de novo lipogenesis is altered. We used Oil Red O to determine the accumulation of lipid droplets in cartilage from mice fed high‐fat diet (HFD) or low‐fat diet (LFD). We further used mass spectrometry‐based lipidomic analyses to quantify levels of different lipid species. Expression of genes involving in fatty acid (FA) uptake, synthesis, elongation, and desaturation were examined using quantitative polymerase chain reaction. To further study the potential mechanisms, we cultured primary mouse chondrocytes under high‐glucose and high‐insulin conditions to mimic the local microenvironment associated with obesity and subsequently examined the abundance of cellular lipid droplets. The acetyl‐CoA carboxylase (ACC) inhibitor, ND‐630, was added to the culture medium to examine the effect of inhibiting de novo lipogenesis on lipid accumulation in chondrocytes. When compared to the mice receiving LFD, the HFD group displayed more chondrocytes with visible intracellular lipid droplets. Significantly higher amounts of total FAs were also detected in the HFD group. Five out of six significantly upregulated FAs were ω‐6 FAs, while the two significantly downregulated FAs were ω‐3 FAs. Consequently, the HFD group displayed a significantly higher ω‐6/ω‐3 FA ratio. Ether linked phosphatidylcholine was also found to be higher in the HFD group. Fatty acid desaturase (Fad1‐3), fatty acid‐binding protein 4 (Fabp4), and fatty acid synthase (Fasn) transcripts were not found to be different between the treatment groups and fatty acid elongase (Elovl1‐7) transcripts were undetectable in cartilage. Ceramide synthase 2 (Cers‐2), the only transcript found to be changed in these studies, was significantly upregulated in the HFD group. In vitro, chondrocytes upregulated de novo lipogenesis when cultured under high‐glucose, high‐insulin conditions, and this observation was associated with the activation of ACC, which was attenuated by the addition of ND‐630. This study provides the first evidence that lipid deposition is increased in cartilage with obesity and that this is associated with the upregulation of ACC‐mediated de novo lipogenesis. This was supported by our observation that ACC inhibition ameliorated lipid accumulation in chondrocytes, thereby suggesting that ACC could potentially be targeted to treat obesity‐associated OA. [ABSTRACT FROM AUTHOR]

Fatty acid composition has an important influence on the fluidity of biological membranes, which is a key factor for the survival of Escherichia coli. With the aim to modify fatty acid composition in this experimentally friendly microorganism, the AtFab2 gene, encoding the Arabidopsis thaliana fatty acid desaturase, was expressed separately and jointly with AtFatA, a fatty acid thioesterase of the same plant origin. The expression of ATFab2 desaturase resulted in an enhancement of cis-vaccenic acid (18:1Δ11) contents, while amounts of palmitioleic acid (16:1Δ9) accumulated by E. coli were increased by 130% for the expression of the AtFatA thioesterase. In the final engineered strain co-expressing AtFab2 and AtFatA, the percentage of palmitic acid (16:0), the most abundant saturated fatty acid found in E. coli, was reduced to 29.9% and the ratio of unsaturated fatty acid to saturated fatty acid reached 2:1. Free fatty acids accounted for about 40% of total fatty acid profiles in the recombinant strain expressing both two genes, and the unsaturated fatty acid contents reached nearly 75% in the free fatty acid profiles. The increase of unsaturated fatty acid level might provide some implication for the construction of cold tolerant strains. [ABSTRACT FROM AUTHOR]

Camelina sativa (L.) Crantz is an indispensable oilseed crop, and its seeds contain many unsaturated fatty acids. FAD (fatty acid desaturase) regulates the synthesis of unsaturated fatty acids. In this research, we performed CsFAD gene family analysis and identified 24 CsFAD genes in Camelina, which were unevenly distributed on 14 of the 19 total chromosomes. Phylogenetic analysis showed that CsFAD includes four subfamilies, supported by the conserved structures and motifs of CsFAD genes. In addition, we investigated the expression patterns of the FAD family in the different tissues of Camelina. We found that CsFAD family genes were all expressed in the stem, and CsFAD2-2 was highly expressed in the early stage of seed development. Moreover, during low temperature (4 °C) stress, we identified that the expression level of CsFAD2-2 significantly changed. By observing the transient expression of CsFAD2-2 in Arabidopsis protoplasts, we found that CsFAD2-2 was located on the nucleus. Through the detection and analysis of fatty acids, we prove that CsFAD2-2 is involved in the synthesis of linolenic acid (C18:3). In conclusion, we identified CsFAD2-2 through the phylogenetic analysis of the CsFAD gene family and further determined the fatty acid content to find that CsFAD2-2 is involved in fatty acid synthesis in Camelina. [ABSTRACT FROM AUTHOR]

Hyperactivation of the phosphatidylinositol-3-kinase (PI3K) pathway is one of the most common events in human cancers. Several efforts have been made toward the identification of selective PI3K pathway inhibitors. However, the success of these molecules has been partially limited due to unexpected toxicities, the selection of potentially responsive patients, and intrinsic resistance to treatments. Metabolic alterations are intimately linked to drug resistance; altered metabolic pathways can help cancer cells adapt to continuous drug exposure and develop resistant phenotypes. Here we report the metabolic alterations underlying the non-small cell lung cancer (NSCLC) cell lines resistant to the usual PI3K-mTOR inhibitor BEZ235. In this study, we identified that an increased unsaturation degree of lipid species is associated with increased plasma membrane fluidity in cells with the resistant phenotype and that fatty acid desaturase FADS2 mediates the acquisition of chemoresistance. Therefore, new studies focused on reversing drug resistance based on membrane lipid modifications should consider the contribution of desaturase activity. [ABSTRACT FROM AUTHOR]

Bone marrow adipocytes (BMAds) constitute the most abundant stromal component of adult human bone marrow. Two subtypes of BMAds have been described, the more labile regulated adipocytes (rBMAds) and the more stable constitutive adipocytes (cBMAds), which develop earlier in life and are more resilient to environmental and metabolic disruptions. In vivo, rBMAds are enriched in saturated fatty acids, contain smaller lipid droplets (LDs) and more readily provide hematopoietic support than their cBMAd counterparts. Mouse models have been used for BMAds research, but isolation of primary BMAds presents many challenges, and thus in vitro models remain the current standard to study nuances of adipocyte differentiation. No in vitro model has yet been described for the study of rBMAds/cBMAds. Here, we present an in vitro model of BM adipogenesis with differential rBMAd and cBMAd-like characteristics. We used OP9 BM stromal cells derived from a (C57BL/6xC3H)F2-op/op mouse, which have been extensively characterized as feeder layer for hematopoiesis research. We observed similar canonical adipogenesis transcriptional signatures for spontaneously-differentiated (sOP9) and induced (iOP9) cultures, while fatty acid composition and desaturase expression of Scd1 and Fads2 differed at the population level. To resolve differences at the single adipocyte level we tested Raman microspectroscopy and show it constitutes a high-resolution method for studying adipogenesis in vitro in a label-free manner, with resolution to individual LDs. We found sOP9 adipocytes have lower unsaturation ratios, smaller LDs and higher hematopoietic support than iOP9 adipocytes, thus functionally resembling rBMAds, while iOP9 more closely resembled cBMAds. Validation in human primary samples confirmed a higher unsaturation ratio for lipids extracted from stable cBMAd-rich sites (femoral head upon hip-replacement surgery) versus labile rBMAds (iliac crest after chemotherapy). As a result, the 16:1/16:0 fatty acid unsaturation ratio, which was already shown to discriminate BMAd subtypes in rabbit and rat marrow, was validated to discriminate cBMAds from rBMAd in both the OP9 model in vitro system and in human samples. We expect our model will be useful for cBMAd and rBMAd studies, particularly where isolation of primary BMAds is a limiting step. [ABSTRACT FROM AUTHOR]

• We identify and characterize 18 FAD genes in the Vanilla planifolia genome. • FAD expression differs between different plant tissues and development stages. • Some VpFAD genes were found to participate in the interaction between Vanilla planifolia and Fusarium oxysporium. Fatty acid desaturase (FAD) plays an essential role in plants; however, FAD genes have not previously been characterized in orchids. Vanilla planifolia is a valuable natural spice in the family Orchidaceae. In this study, we identified 18 FAD genes in this species and analyzed their protein characteristics, chromosome distribution, phylogeny, gene structure, and conserved motifs. Transcriptome data analysis showed that the 18 genes showed different expression patterns in six tissues (seed, placental laminae, mesocarp, hair, stem, and leaf) and various stages of seed development (6 weeks, 8 weeks, 10 weeks, 3 months, 5 months, and 6 months). In addition, the expression profile of infected Fusarium oxysporum indicated that the FAD genes play an essential role in dealing with pathogen invasion. This study provides a comprehensive understanding of the FAD family in Vanilla planifolia as well as information on pathogen immunity, which can provide a reference for further functional research. [ABSTRACT FROM AUTHOR]

Alpha-linolenic acid (ALA) is the precursor for the synthesis of essential fatty acids such as EPA and DHA. The dietary requirement of omega 3 fatty acid is 1.59 g for females and 2.06 g for males. There is an urgent need for enhancing omega 3 fatty acid in vegetative sources. Sesame oil is unique in its flavor and medicinal properties but it contains only traces of ALA. In this study attempts were made to increase the omega 3 fatty acid content in sesame seeds using a bi-functional ∆12/ω3 fatty acid desaturase gene from Fusarium moniliforme. Sesame seed-specific promoter isolated from oleic acid desaturase was used for high and tissue-specific expression. The fungal bi-functional ∆12/ω3 fatty acid desaturase gene under the control of sesame seed-specific promoter was transferred to sesame the ALA content in transgenic sesame was evaluated. Expression of fungal ∆12/ω3 fatty acid desaturase gene resulted in increased ALA content up to 12 fold in transformed sesame plants compared to untransformed control. [Display omitted] • Transgenic sesame plants were generated using fungal bi-functional desaturase gene to enhance omega 3 fatty acid. • This opens the possibility of using sesame leaves for omega 3 fatty acid production. • Constitutive promoters produce more of ALA throughout the plant than the strong oleic acid promoter in seeds. [ABSTRACT FROM AUTHOR]

This review highlights the key role of fatty acid desaturases in the synthesis of naturally occurring, more common and not unsaturated fatty acids. The three major classes of fatty acid desaturases, such as acyl‐lipid, acyl‐acyl carrier protein and acyl‐coenzyme A, are described in detail, with particular attention to the cellular localisation, the structure, the substrate and product specificity and the expression and regulation of desaturase genes. The review also gives an insight into the biocatalytic reaction of fatty acid desaturation by covering the general and more class‐specific mechanistic studies around the synthesis of unsaturated fatty acids Finally, we conclude the review by looking at the numerous novel applications for desaturases in order to meet the very high demand for polyunsaturated fatty acids, taking into account the opportunity for the development of new, more efficient, easily reproducible, sustainable bioengineering advances in the field. [ABSTRACT FROM AUTHOR]

There are differences in lipid deposition in fatty-type (FT) and lean-type (LT) ducks. Fatty ducks have a higher rate of sebum and abdominal fat, lower meat yield and hepatic lipid contents than LT ducks. However, the underlying changes in gene expression profiles regarding the lipid deposition between FT and LT ducks have not yet been clarified. To identify the differentially expressed genes in the liver, sebum, and abdominal fat between both ducks, we identified the gene expression profiles in the liver, sebum, and abdominal fat derived from FT and LT ducks by comparing the multistage transcriptomes. Our results showed that there were 622, 1536, and 224 differentially expressed genes (DEGs) in the liver, sebum, and abdominal fat between the FT and LT ducks, respectively. KEGG enrichment showed that the DEGs related to lipid metabolism were enriched in the biosynthesis of unsaturated fatty acid, glycerolipid and fatty acid metabolism in the liver; and were enriched in the fatty acid metabolism, fatty acid biosynthesis, glycerolipid metabolism, linoleic acid metabolism, and the PPAR signaling pathway in the sebum. There was no pathway related to a lipid metabolism enriched in abdominal fat. A gene functional analysis showed that the DEGs involved in adipogenesis were found to be upregulated. In contrast, those involved in lipolysis were downregulated in the liver and serum of FT ducks. The DEGs showed that ATP-binding cassette sub-family G member 8 (ABCG8), fatty acid synthase (FASN), and phospholipid transfer protein (PLTP) were highly expressed in the liver of FT ducks, and acyl-CoA synthetase long-chain family member3 (ACSL3), ACSL5, ACSL6, 1-acyl-sn-glycerol-3-phosphate acyltransferase alpha (AGPAT1), AGPAT9, ELOVL fatty acid elongase 6 (ELVOL6), fatty acid desaturase 1 (FADS1), FADS2, monoacylglycerol O-acyltransferase 1 (MOGAT1), serine/threonine kinase 17a (STK17A), and serine/threonine kinase 39 (STK39) were highly expressed in the sebum of FT ducks. A weighted correlation network analysis (WGCNA) of the DEGs showed ABCG8, FADS2, ACSL5, and ELOVL6 positively correlated with hepatic fatty acid synthesis, and AGPAT1, STK17A, STK32A, FADS1, and ACSL3 positively correlated with lipid deposition in the sebum. In summary, ABCG8 might be the key gene for the reduced hepatic lipid deposition in FT Pekin ducks, and FADS2, ACSL5, ELOVL6, AGPAT1, STK17A, STK32A, FADS1, and ACSL3 were the key genes for lipid deposition in the sebum of FT Pekin ducks. Our results provide new insights into the transcriptome regulation in lipid deposition of Pekin ducks and will be helpful for duck breeding. [ABSTRACT FROM AUTHOR]

Linoleic acid is the material for biosynthesis of sex attracting and blocking (postmating) pheromones in Nasonia vitripennis, it is synthesized from oleic acid by a male‐biased fatty acid desaturase (SCD5a). In this study, we developed a specific antibody and further characterized the expression patterns of SCD5a in males at different mating stages by western blot. SCD5a was mainly expressed in male heads rather than in abdomens. Along with the aging process (from Day 1 to Day 3), SCD5a increased significantly. Compared with virgin males, mated males showed higher levels of SCD5a. Likewise, abdomen dipping frequency, during which males release attracting pheromone, increased with age and mating. Moreover, real‐time quantitative PCR revealed that genes responsible for the first three steps of attracting pheromone biosynthesis were more highly expressed in head than in abdomen, but the final gene for transformation of attracting pheromone was more highly expressed in abdomen than in head. These results suggest that linoleic acid for biosynthesis of attracting pheromones may also originate from the head rather than only synthesized at the rectal vesicles. Research Highlights: SCD5a was expressed more in the head than in the abdomen.Linoleic acid for attracting pheromone synthesis may also originate from male's head.Aged or mated males released more attracting pheromone and possess a higher possibility of successful mating. [ABSTRACT FROM AUTHOR]

Chaulmoogra oil is found in the seeds of Carpotroche brasiliensis (Raddi) Endl. (syn. Mayna brasiliensis Raddi), an oil tree of the Achariaceae family and native to Brazil's Atlantic Forest biome, which is considered the fifth most important biodiversity hotspot in the world. Its main constituents are cyclopentenic fatty acids. Chaulmoogra oil has economic potential because of its use in the cosmetics industry and as a drug with anti-tumor activity. The mechanisms related to the regulation of oil biosynthesis in C. brasiliensis seeds are not fully understood, especially from a tissue-specific perspective. In this study, we applied a de novo transcriptomic approach to investigate the transcripts involved in the lipid pathways of C. brasiliensis and to identify genes involved in lipid biosynthesis. Comparative analysis of gene orthology, expression analysis and visualization of metabolic lipid networks were performed, using data obtained from high-throughput sequencing (RNAseq) of 24 libraries of vegetative and reproductive tissues of C. brasiliensis. Approximately 10.4 million paired-end reads (Phred (Q) > 20) were generated and re-assembled into 107,744 unigenes, with an average length of 340 base pairs (bp). The analysis of transcripts from different tissues identified 1131 proteins involved in lipid metabolism and transport and 13 pathways involved in lipid biosynthesis, degradation, transport, lipid bodies, and lipid constituents of membranes. This is the first transcriptome study of C. brasiliensis, providing basic information for biotechnological applications of great use for the species, which will help understand chaulmoogra oil biosynthesis. [ABSTRACT FROM AUTHOR]

Background: The dietary glycemic index (GI) has been introduced as a novel index to elucidate the potential of foods to increase postprandial glucose. According to the limited available data about the association of GI with cardio-metabolic risk factors such as lipid profile, blood glucose markers, and blood pressure in developing countries, the current study was conducted to investigate this association in apparently obese individuals. Method and material: Three hundred forty-seven obese adults were recruited in the present cross-sectional study. A validated 147-food item semi-quantitative food frequency questionnaire (FFQ) was used to evaluate the usual dietary intake of study participants. Dietary GI was calculated using the international GI database. Fatty acid desaturase (FADs)2 gene variants were determined according to polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). ANOVA was used to compare study variables across different tertile of GI. Results: We found significant differences in terms of anthropometric parameters [weight (P = 0.038), waist circumference (WC) (P = 0.023), weight to hip ratio (WHR) (P = 0.007), and fat-free mass (FFM) (P < 0.001)] between different tertiles of GI. Similarly, energy and macronutrient intakes had a significant difference across dietary GI, and subjects with a higher dietary intake of energy and macronutrients (carbohydrate, protein, and total fat) were assigned to the third tertile of dietary GI (P < 0.001). While there was no significant difference in terms of cardio-metabolic risk factors in different dietary GI tertiles. Moreover, the total GI score was non-significantly higher in the TT genotype of FADS2 gene polymorphism compared with other genotypes. While no significant difference was observed between FADS2 genotype frequencies in different GI tertiles. Conclusion: Calculated dietary GI was associated with several cardio-metabolic risk factors in obese individuals. However, further prospective studies and clinical trials are needed to confirm our findings. [ABSTRACT FROM AUTHOR]

Seeds directly determine the survival and population size of woody plants, but the genetic basis of seed weight in woody plants remain poorly explored. To identify genetic variations and candidate genes responsible for seed weight in natural woody populations, we investigated the hundred-seed weight of 198 paper mulberry individuals from different areas. Our results showed that the hundred-seed weight of paper mulberry was significantly associated with the bioclimatic variables of sampling sites, which increased from south to north along the latitudinal-temperature gradient. Using 2,414,978 high-quality SNPs from re-sequencing data, the genome-wide association analysis of the hundred-seed weight was performed under three models, which identified 148, 19 and 12 associated genes, respectively. Among them, 25 candidate genes were directly hit by the significant SNPs, including the WRKY transcription factor, fatty acid desaturase, F-box protein, etc. Most importantly, we identified three crucial genetic variations in the coding regions of candidate genes (Bp02g2123, Bp01g3291 and Bp10g1642), and significant differences in the hundred-seed weight were detected among the individuals carrying different genotypes. Further analysis revealed that Bp02g2123 encoding a fatty acid desaturase (FAD) might be a key factor affecting the seed weight and local climate adaptation of woody plants. Furthermore, the genome-wide investigation and expression analysis of FAD genes were performed, and the results suggested that BpFADs widely expressed in various tissues and responded to multiple phytohormone and stress treatments. Overall, our study identifies valuable genetic variations and candidate genes, and provides a better understanding of the genetic basis of seed weight in woody plants. [ABSTRACT FROM AUTHOR]

One line of research on the possible ways of inhibiting the growth of glioblastoma multiforme (GBM), a brain tumor with a very poor prognosis, is the analysis of its metabolism, such as fatty acid synthesis by desaturases and elongases. This study examines the expression of elongases ELOVL1, ELOVL2, ELOVL3, ELOVL4, ELOVL5, ELOVL6, and ELOVL7 in GBM tumor samples from 28 patients (16 men and 12 women), using a quantitative real-time polymerase chain reaction (qRT-PCR). To demonstrate the influence of the tumor microenvironment on the tested elongases, U-87 MG cells were cultured in nutrient-deficient conditions and with cobalt chloride (CoCl2) as a hypoxia-mimetic agent. The results showed that the expression of ELOVL1 and ELOVL7 in the GBM tumor was lower than in the peritumoral area. The expression of six of the seven studied elongases differed between the sexes. Hypoxia increased the expression of ELOVL5 and ELOVL6 and decreased the expression of ELOVL1, ELOVL3, ELOVL4, and ELOVL7 in U-87 MG cells. These results indicate that the synthesis of fatty acids, especially polyunsaturated fatty acids (PUFA), in GBM tumors may be higher in men than in women. In contrast, the synthesis of saturated fatty acids (SFA) may be higher in women than in men. [ABSTRACT FROM AUTHOR]

Apart from the oncometabolite succinate, little studies have appeared on extra-mitochondrial pathways in Succinate Dehydrogenase (SDH) genetic deficiency. The role of NADH/NAD+ redox status and dependent pathways was recently emphasized. Therein, fatty acid (FA) metabolism data were collected here in 30 patients with a loss of function (LOF) variant in one SDHx gene (either with a pheochromocytoma/paraganglioma (PPGL) or asymptomatic) and in 22 wild-type SDHx controls (with PPGL or asymptomatic). Blood acylcarnitines in two patients, peroxisomal biomarkers, very long-chain saturated FA (VLCFA), and C20 to C24 n-3 polyunsaturated fatty acids (PUFA), in all patients were measured by mass spectrometry. Preliminary data showed elevated even and odd long- and very long-chain acylcarnitines in two patients with a SDHB variant. In the whole series, no abnormalities were observed in biomarkers of peroxisomal β-oxidation (C27-bile acids, VLCFAs and phytanic/pristanic acids) in SDHx patients. However, an increased hexaene to pentaene PUFA ratio ([TetraHexaenoic Acid + DocosaHexaenoic Acid]/[n-3 DocosaPentaenoic Acid + EicosaPentaenoic Acid]) was noticed in patients with SDHC/SDHD variants vs patients with SDHA/SDHB variants or controls, suggesting a higher degree of unsaturation of PUFAs. Within the group with a SDHx variant, Eicosapentaenoate/Tetracosahexaenoate ratio, as an empiric index of shortening/elongation balance, discriminated patients with PPGL from asymptomatic ones. Present findings argue for stimulated elongation of saturated FAs, changes in shortening/elongation balance and desaturation rates of C20–C24 PUFAs in SDH-deficient patients with PPGL. Overall, oxidation of NADH sustained by these pathways might reflect or impact glycolytic NAD+ recycling and hence tumor proliferation. • Unsaturation of serum C20–C24 PUFAs is higher in patients with SDHC/D germline variant. • Serum EPA/THA ratio increases in patients with germline SDHx variant and paraganglioma. • This suggests higher Fatty Acid desaturase and elongase activities in SDH deficiency. • Both biochemical pathways increase cytosolic NAD + recycling. [ABSTRACT FROM AUTHOR]

Rice, as one of the main food crops, provides a vital source of dietary energy for over half the world's population. The OsFAD3 gene encodes fatty acid desaturase, catalyzing the conversion of linoleic acid (LA) to alpha-linolenic acid (ALA) in rice. However, the genetic characterization of OsFAD3 and its role in the conversion of LA to ALA remains elusive. Here, we validated the effects of two homologous genes, OsFAD3-1 and OsFAD3-2, on the ALA and LA/ALA ratio in rice grains using near-isogenic lines. Two major haplotypes of OsFAD3-1 are identified with different effects on the ALA and LA/ALA ratio in rice germplasm. High expression of OsFAD3-1 is associated with high ALA accumulation and eating quality of rice grains. Overexpression of OsFAD3-1 driven by a seed-specific promoter increases the ALA content up to 16-fold in the endosperm. A diagnostic marker is designed based on an 8-bp insertion/deletion in the OsFAD3-1 promoter, which can recognize OsFAD3-1 alleles in rice. These results indicate that OsFAD3-1 is a useful target gene in marker-assisted breeding programs to improve varieties with high ALA and appropriate LA/ALA ratio in brown rice. [ABSTRACT FROM AUTHOR]

Fatty acid desaturases (FADs) modulate carbon–carbon single bonds to form carbon–carbon double bonds in acyl chains, leading to unsaturated fatty acids (UFAs) that have vital roles in plant growth and development and their response to environmental stresses. In this study, a total of 23 Populus trichocarpaFAD (PtFAD) candidates were identified from the poplar genome and clustered into seven clades, including FAB2, FAD2, FAD3/7/8, FAD5, FAD6, DSD, and SLD. The exon–intron compositions and conserved motifs of the PtFADs, clustered into the same clade, were considerably conserved. It was found that segmental duplication events are predominantly attributable to the PtFAD gene family expansion. Several hormone- and stress-responsive elements in the PtFAD promoters implied that the expression of the PtFAD members was complicatedly regulated. A gene expression pattern analysis revealed that some PtFAD mRNA levels were significantly induced by abiotic stress. An interaction proteins and gene ontology (GO) analysis indicated that the PtFADs are closely associated with the UFAs biosynthesis. In addition, the UFA contents in poplars were significantly changed under drought and salt stresses, especially the ratio of linoleic and linolenic acids. The integration of the PtFAD expression patterns and UFA contents showed that the abiotic stress-induced PtFAD3/7/8 members mediating the conversion of linoleic and linolenic acids play vital roles in response to osmotic stress. This study highlights the profiles and functions of the PtFADs and identifies some valuable genes for forest improvements. [ABSTRACT FROM AUTHOR]

CRISPR–Cas9 gene-editing technology enables efficient genome editing in various plants, but entails difficulties and inefficiencies in transforming allotetraploid soybeans. Therefore, for producing transgenic soybeans using high-efficiency CRISPR–Cas9, a method for verifying the mutation efficiency of the target gene guide RNA is essential. Here, we present an experimental method using soybean protoplasts to confirm the effectiveness of single guide RNAs (sgRNAs) and sgRNA clones used for target gene mutagenesis to produce CRISPR–Cas9-mediated transgenic soybeans. In addition, we propose a method to improve the time-consuming process of producing CRISPR–Cas9-mediated transgenic soybeans. First, the fatty acid desaturase 2 (FAD2) gene was selected as a target gene for CRISPR–Cas9 application, and each of the three sgRNAs of the FAD2 isoforms (A, B) was produced based on the corresponding gene sequence. The sgRNAs of the three FAD2 genes were transfected into soybean protoplasts, and next-generation sequencing was performed using the isolated genomic DNA. The two FAD2-1A-1 and FAD2-1B-1 sgRNAs exhibited the highest insertion and deletion (indel) efficiency. Next, the selected FAD2-1A-1 and FAD2-1B-1 sgRNAs were cloned into three different binary vectors, and genomic DNA was isolated after transfection into the protoplast. Indel efficiency was high when pECO202 for FAD2-1A-1 and pECO201 for FAD2-1B-1 were used. Transgenic soybean was produced using the FAD2-1A-1::pECO202 and FAD2-1B-1::pECO201 sgRNA clones. The presented soybean protoplast transformation method can verify the mutation effect of specific sgRNAs and sgRNA clones of the soybean target gene used for CRISPR–Cas9 in a short period of time and reduce the time consumption of transgenic soybean production. [ABSTRACT FROM AUTHOR]

As a crop irrigated primarily by rain, the quality and yield of peanuts are significantly limited by drought. To date, many studies have indicated that fatty acid desaturase (FAD) genes enhance plant tolerance to drought stresses. In this study, 16, 15, and 31 FADs were identified in Arachis duranensis, Arachis ipaensis, and Arachis hypogaea, respectively. All the FADs were divided into four subfamilies, which had relatively conserved gene structures, motifs, and domains. The synteny relationships and chromosomal position analysis showed that the FADs in subgenome pairs, A. duranensis-A. hypogaea (AA) and A. ipaensis-A. hypogaea (BB), were homologous, and their physical locations were consistent. The Ka/Ks results indicated that nine FAD genes underwent a purifying selection, and Ah|FAD3.2 experienced positive selection during tetraploid peanut speciation. Various cis-acting elements related to hormone signaling and stress responsiveness in promoters and the predicted miRNA targeting Ah|FADs suggested that these genes play crucial roles in drought tolerance. The expression profiles of Ah|FADs in 22 tissues and drought-tolerant and -sensitive cultivars under drought stress suggested that 4 and 6 FADs were putative genes related to oil accumulation and drought, respectively. These findings will help provide insight into the potential functional roles of the FAD genes, which may aid in dealing with plant drought stress. [ABSTRACT FROM AUTHOR]

Sterols in eukaryotic cells play important roles in modulating membrane fluidity and in cell signaling and trafficking. During evolution, a combination of gene losses and acquisitions gave rise to an extraordinary diversity of sterols in different organisms. The sterol C-22 desaturase identified in plants and fungi as a cytochrome P-450 monooxygenase evolved from the first eukaryotic cytochrome P450 and was lost in many lineages. Although the ciliate Tetrahymena thermophila desaturates sterols at the C-22 position, no cytochrome P-450 orthologs are present in the genome. Here, we aim to identify the genes responsible for the desaturation as well as their probable origin. We used gene knockout and yeast heterologous expression approaches to identify two putative genes, retrieved from a previous transcriptomic analysis, as sterol C-22 desaturases. Furthermore, we demonstrate using bioinformatics and evolutionary analyses that both genes encode a novel type of sterol C-22 desaturase that belongs to the large fatty acid hydroxylase/desaturase superfamily and the genes originated by genetic duplication prior to functional diversification. These results stress the widespread existence of nonhomologous isofunctional enzymes among different lineages of the tree of life as well as the suitability for the use of T. thermophila as a valuable model to investigate the evolutionary process of large enzyme families. [ABSTRACT FROM AUTHOR]

This study investigated the expression levels of FAD2 genes important for the conversion of oleic acid to linoleic acid at cotyledon, root and leaf tissues of four different safflower cultivars (Olas, Remzibey, Dincer and Gokturk) subjected to B by qRT-PCR. Safflower species were grown in a controlled environmental growth chamber for 21 days and then exposed to different B concentrations ranging from 20 to 1 280 µmol for 24 h. RNA isolation, cDNA synthesis and RT-PCR analysis were performed on root, cotyledon and leaf tissues exposed to B stress for 24 h. It was determined that the expression levels of FAD2 genes decreased in the safflower cultivars exposed to increasing B concentrations. Under B stress conditions, the expression levels of FAD2 genes revealed an overall pattern of increase and reduction up to 160 µmol relative to the control group, and they reached the highest expression level. After 320 µmol, the activity of FAD2 genes was almost absent at increasing concentrations. All results show that the application of B causes significant changes in the expression of FAD2 genes and plays an important role in the defence mechanism against increased B toxicity. [ABSTRACT FROM AUTHOR]

Background: Biological and abiotic stresses such as salt, extreme temperatures, and pests and diseases place major constraints on plant growth and crop yields. Fatty acids (FAs) and FA- derivatives are unique biologically active substance that show a wide range of functions in biological systems. They are not only participated in the regulation of energy storage substances and cell membrane plasm composition, but also extensively participate in the regulation of plant basic immunity, effector induced resistance and systemic resistance and other defense pathways, thereby improving plant resistance to adversity stress. Fatty acid desaturases (FADs) is involved in the desaturation of fatty acids, where desaturated fatty acids can be used as substrates for FA-derivatives. Objective: In this paper, the role of omega-FADs (ω-3 FADs and ω-6 FADs) in the prokaryotic and eukaryotic pathways of fatty acid biosynthesis in plant defense against stress (biological and abiotic stress) and the latest research progress were summarized. Moreover' the existing problems in related research and future research directions were also discussed. Results: Fatty acid desaturases are involved in various responses of plants during biotic and abiotic stress. For example, it is involved in regulating the stability and fluidity of cell membranes, reactive oxygen species signaling pathways, etc. In this review, we have collected several experimental studies to represent the differential effects of fatty acid desaturases on biotic and abiotic species. Conclusion: Fatty acid desaturases play an important role in regulating biotic and abiotic stresses. [ABSTRACT FROM AUTHOR]

Background: Bamboo is an important nontimber forestry product worldwide, while growth, development and geographic distribution of bamboo are often affected by abiotic stresses. Fatty acid desaturases have important roles in regulating plant abiotic stress tolerance, especially low-temperature. However, there is no report on genome-wide of FAD genes in bamboo under abiotic stresses., Results: A toltal of 43 PeFAD genes were identified in moso bamboo genome, which were unevenly located in 17 scaffolds. Phylogenetic analysis indicated that PeFAD genes were divided into 6 groups and ADS/FAD5 group was absence in momo bamboo, and gene structure and histidine-motifs remained highly conserved in each group. The expansion of PeFAD genes was mainly caused by tandem and segmental duplications of SAD/FAB2 group. We also identified 59 types of miRNAs targeting PeFAD genes. RNA-seq data indicated that PeFAD genes were transcribed in various organs/tissues with different degrees, and responded to abiotic stresses and hormone treatments, including cold, salt, drought, SA, ABA, BR, NAA and GA. Co-expression analysis under cold stress showed that PeCBF3 might directly bind the promoter of top cold-responsive PeSLD1 gene that contained LTR cis-element and DRE core element. The qRT-PCR assay also validated the expression pattern of PeSLD1 and its upstream regulatory gene PeCBF3., Conclusion: In this study, we performed comprehensive genome-wide survey of PeFAD genes in moso bamboo and analyzed their expression patterns in various tissues and organs, and under abiotic stresses and phytohormones treatment. The qRT-PCR assay validated the cold inducibility of PeSLD1 and PeCBF3. This work showed critical roles of PeFAD genes in abiotic stresses responses. This is the first report on genome-wide analysis of PeFAD genes in moso bamboo, which will provide critical gene resources for molecular breeding of stress-toleranct moso bamboo., Competing Interests: Declarations. Ethics approval and consent to participate: The moso bamboo (P. edulis) materials used in qRT-PCR analysis were taken from the botanical garden of bamboo at Key Laboratory of Sichuan Province for Bamboo Pests Control and Resource Development, Leshan Normal University, Leshan, Sichuan. The collection of plant material complied with relevant institutional, national, and international guidelines and legislation. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Seabuckthorn ( Hippophae rhamnoides Linn.) is a commonly utilized medicinal crop with various applications in the treatment of different diseases. Two particularly noteworthy nutrients in seabuckthorn fruit are seabuckthorn oil and flavonoids. In recent years, seabuckthorn oil has attracted considerable attention due to its perceived benefits for beauty and healthcare. Consequently, there is a clear need for further research into seabuckthorn oil. While numerous studies have been conducted on the regulation of oil by the FAD2 gene family, there is a paucity of literature examining the molecular mechanism of FAD2 gene involvement in seabuckthorn oil regulation. Accordingly, two FAD2 genes have been identified in seabuckthorn, which are classified differently and perform distinct functions. Both genes are located in the endoplasmic reticulum. Following transient expression in seabuckthorn fruits, it was observed that HrFAD2-1 and HrFAD2-3 were capable of influencing the synthesis of α-linolenic acid, with HrFAD2-1 additionally demonstrated to facilitate the synthesis of lysophosphatidic acid. All of the aforementioned genes have been observed to promote jasmonic acid (JA) synthesis. The heterologous transformation of Linum usitatissimum demonstrates that both HrFAD2-1 and HrFAD2-3 are capable of promoting plant growth. The HrFAD2-1 gene was observed to significantly increase the content of major fatty acids in Linum usitatissimum Linn seeds, whereas the HrFAD2-3 gene appeared to be primarily involved in the regulation of plant growth and development. In conclusion, a preliminary investigation into the functions of the HrFAD2-1 and HrFAD2-3 genes in fatty acid synthesis was conducted. This revealed that HrFAD2-1 is closely associated with oleic acid synthesis and acts as a negative regulator. Furthermore, our findings will provide a foundation for subsequent investigations into the fatty acid synthesis pathway in Hippophae rhamnoides oil, offering a theoretical basis for subsequent studies at the molecular level.

Background: Chia (Salvia hispanica L.) seeds have become increasingly popular among health-conscious consumers owing to their high content of ω-3 fatty acids, which provide various health benefits. Comprehensive chemical analyses of the fatty acids and proteins in chia seeds have been conducted, revealing their functional properties. Recent studies have confirmed the high ω-3 content of chia seed oil and have hinted at additional functional characteristics., Scope: This review article aims to provide an overview of the botanical, morphological and biochemical features of chia plants, seeds and seed mucilage. Additionally, we discuss the recent developments in genetic and molecular research on chia, including the latest transcriptomic and functional studies that examine the genes responsible for chia fatty acid biosynthesis. In recent years, research on chia seeds has shifted its focus from studying the physicochemical characteristics and chemical composition of seeds to understanding the metabolic pathways and molecular mechanisms that contribute to their nutritional benefits. This has led to a growing interest in various pharmaceutical, nutraceutical and agricultural applications of chia. In this context, we discuss the latest research on chia and the questions that remain unanswered, and we identify areas that require further exploration., Conclusions: Nutraceutical compounds associated with significant health benefits, including ω-3 polyunsaturated fatty acids, proteins and phenolic compounds with antioxidant activity, have been measured in high quantities in chia seeds. However, comprehensive investigations through both in vitro experiments and in vivo animal and controlled human trials are expected to provide greater clarity on the medicinal, antimicrobial and antifungal effects of chia seeds. The recently published genome of chia and gene-editing technologies, such as CRISPR, facilitate functional studies deciphering molecular mechanisms of biosynthesis and metabolic pathways in this crop. This necessitates development of stable transformation protocols and creation of a publicly available lipid database, mutant collection and large-scale transcriptomic datasets for chia., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

The olive fruit is a drupe whose development and ripening takes several months from flowering to full maturation. During this period, several biochemical and physiological changes occur that affect the skin color, texture, composition, and size of the mesocarp. The final result is a fruit rich in fatty acids, phenolic compounds, tocopherols, pigments, sterols, terpenoids, and other compounds of nutritional interest. In this work, a transcriptomic analysis was performed using flowers (T0) and mesocarp tissue at seven different stages during olive fruit development and ripening (T1-T7) of the 'Picual' cultivar. A total of 1755 genes overexpressed at any time with respect to the flowering stage were further analyzed. These genes were grouped into eight clusters based on their expression profile. The gene enrichment analysis revealed the most relevant biological process of every cluster. Highlighting the important role of hormones at very early stages of fruit development (T1, Cluster 1), whereas genes involved in fatty acid biosynthesis were relevant throughout the fruit developmental process. Hence, genes coding for different fatty acid desaturase (SAD, FAD2, FAD3, FAD4, FAD5, FAD6, and FAD7) enzymes received special attention. In particular, 26 genes coding for different fatty acid desaturase enzymes were identified in the 'Picual' genome, contributing to the improvement of the genome annotation. The expression pattern of these genes during fruit development corroborated their role in determining fatty acid composition.

This study reports the use of the Arabidopsis KASII promoter ( AtKASII ) to develop an efficient CRISPR/Cas9 system for soybean genome editing. When this promoter was paired with Arabidopsis U6 promoters to drive Cas9 and single guide RNA expression, respectively, simultaneous editing of the three fatty acid desaturase genes GmFAD2-1A , GmFAD2-1B , and GmFAD3A occurred in more than 60% of transgenic soybean lines at T 2 generation, and all the triple mutants possessed desirable high-oleic traits. In sharp contrast, not a single line underwent simultaneous editing of the three target genes when AtKASII was replaced by the widely used AtEC1.2 promoter. Furthermore, our study showed that the stable and inheritable mutations in the high-oleic lines did not alter the overall contents of oil and protein or amino acid composition while increasing the oleic acid content up to 87.6% from approximately 23.8% for wild-type seeds, concomitant with 34.4- and 3.7-fold reductions in linoleic and linolenic acid, respectively. Collectively, this study demonstrates that the AtKASII promoter is highly promising for optimization of the CRISPR/Cas9 system for genome editing in soybean and possibly beyond.

Fatty acid desaturase catalyzes the desaturation reactions by inserting double bonds into the fatty acyl chain, producing unsaturated fatty acids, which play a vital part in the synthesis of polyunsaturated fatty acids. Though soluble fatty acid desaturases have been described extensively in advanced organisms, there are very limited studies of membrane fatty acid desaturases due to their difficulties in producing a sufficient amount of recombinant desaturases. However, the advancement of technology has shown substantial progress towards the development of elucidating crystal structures of membrane fatty acid desaturase, thus, allowing modification of structure to be manipulated. Understanding the structure, mechanism, and biosynthesis of fatty acid desaturase lay a foundation for the potential production of various strategies associated with alteration and modifications of polyunsaturated fatty acids. This manuscript presents the current state of knowledge and understanding about the structure, mechanisms, and biosynthesis of fatty acid desaturase. In addition, the role of unsaturated fatty acid desaturases in health and diseases is also encompassed. This will be useful in understanding the molecular basis and structural protein of fatty acid desaturase that are significant for the advancement of therapeutic strategies associated with the improvement of health status. Key points: • Current state of knowledge and understanding about the biosynthesis, mechanisms, and structure of fatty acid desaturase. • The role of unsaturated fatty acid desaturase. • The molecular basis and structural protein elucidated the crystal structure of fatty acid desaturase. [ABSTRACT FROM AUTHOR]

As a glycophyte plant, pepper (Capsicum annuum L.) is widely cultivated worldwide, but its growth is susceptible to salinity damage, especially at the seedling stage. Here, we conducted a study to determine the physiological and transcriptional differences between two genotype seedlings (P300 and 323F3) with contrasting tolerance under salt stress. The P300 seedlings were more salt-tolerant and had higher K+ contents, higher antioxidase activities, higher compatible solutes, and lower Na+ contents in both their roots and their leaves than the 323F3 seedlings. During RNA-seq analysis of the roots, more up-regulated genes and fewer down-regulated genes were identified between salt-treated P300 seedlings and the controls than between salt-treated 323F3 and the controls. Many ROS-scavenging genes and several SOS pathway genes were significantly induced by salt stress and exhibited higher expressions in the salt-treated roots of the P300 seedlings than those of 323F3 seedlings. Moreover, biosynthesis of the unsaturated fatty acids pathway and protein processing in the endoplasmic reticulum pathway were deeply involved in the responses of P300 to salt stress, and most of the differentially expressed genes involved in the two pathways, including the genes that encode mega-6 fatty acid desaturases and heat-shock proteins, were up-regulated. We also found differences in the hormone synthesis and signaling pathway genes in both the P300 and 323F3 varieties under salt stress. Overall, our results provide valuable insights into the physiological and molecular mechanisms that affect the salt tolerance of pepper seedlings, and present some candidate genes for improving salt tolerance in pepper. [ABSTRACT FROM AUTHOR]

However, the lipid phenotypes observed in this mutant appeared to be unrelated to O-glycosyl hydrolase activity due to the lack of segregation of lipid phenotypes with the T-DNA insertion in I At5g64790 i , followed by backcrossing. Google Scholar Crossref Search ADS PubMed WorldCat 19 Pucker B., Kleinbolting N. and Weisshaar B. (2021) Large scale genomic rearrangements in selected Arabidopsis thaliana T-DNA lines are caused by T-DNA insertion mutagenesis. Of the 364 Arabidopsis mutant alleles studied, the authors focused on one mutant allele (Salk 109175C), which displayed significant alterations in leaf chloroplast glycerolipid composition. By comparing the lipid profile of I fad6-3 i with that of I fad6-1 i , the authors showed that both mutants had very low levels of unsaturated fatty acids produced only in plastids (16:2 and 16:3), indicating that I fad6-3 i is also the loss-of-function mutant allele. [Extracted from the article]