Diacylglycerol Acyltransferase Genes Research Articles

EgbHLH63 negatively regulates palm fruit oil accumulation by repressing EgDGAT1 transcription

Diacylglycerol acyltransferase (DGAT) is a crucial enzyme involved in triacylglycerol (TAG) accumulation. To investigate the regulation of DGAT genes in the mesocarp of oil palm, a key transcription factor, EgbHLH63, was identified by a yeast one-hybrid assay. The interaction between EgbHLH63 and the EgDGAT1 promoter (proEgDGAT1) and its potential role in TAG synthesis were investigated. Binding of EgbHLH63 to proEgDGAT1 was confirmed by dual-luciferase reporter gene assays and EMSA in vitro. Overexpression of EgbHLH63 in oil palm protoplasts resulted in a significant reduction in EgDGAT1 expression. Silence of EgbHLH63 in transgenic embryoids restored high levels of EgDGAT1 expression and significantly increased TAG content. In addition, two other transcription factors, EgULT1 and EgZFP, were identified as interacting with EgbHLH63. They recognized B-box and AT-rich motifs in the EgDGAT1 promoter, respectively. These two transcription factors also negatively regulated EgDGAT1 expression, thereby affecting oil accumulation. Collectively, the results shed light on the lipid mechanism pathway involving EgDGAT1 in the mesocarp and offer promising research avenues for improving oil yield and quality in oil palm.

DGAT1 Gene Polymorphism in Morkaraman and Tushin

This study aims to investigate the polymorphism of the Diacylglycerol acyltransferase1 (DGAT1) gene locus in 105 Morkaraman and 65 Tushin lambs to determine the distribution of genotype and allele frequencies of lambs in terms of related genes. DGAT1/Alu1 gene polymorphism was defined by using the PCR-RFLP method in the DNAs isolated from hair samples taken from Morkaraman and Tushin lambs used in this study. PCR- RFLP products were run in an electrophoresis medium and the results were visualized on an ultraviolet (UV) transluminator. When the population was examined in terms of allele frequencies, it was defined that the C allele and the T allele were 0.72% and 0.28% for the Morkaraman, and 0.71% and 0.29% for Tushin, respectively. The CC, CT, and TT genotype frequencies of the DGAT1 gene in the population were found to be 53.3%, 38.1%, and 8.6% for the Morkaraman and 50.8%, 40.0%, and 9.2% for the Tushin, respectively. In the Hardy-Weinberg genetic equilibrium test, it was observed that the distribution of genotype frequencies was in balance (P>0.05) in the population. It has been defined that the genotype and allele frequencies determined in terms of DGAT1 gene polymorphism may be found to be sufficient to reveal the genotype diversity of the breeds. The genotype and allele frequencies determined in terms of DGAT1 gene polymorphism were sufficient to reveal the genotype diversity of the breed, the sheep with CC genotype are economically advantageous in the herd, and therefore DGAT1 gene can be used for marker-assisted selection (MAS).

Epichloë fungal endophyte interactions in perennial ryegrass (Lolium perenne L.) modified to accumulate foliar lipids for increased energy density

BackgroundCommercial cultivars of perennial ryegrass infected with selected Epichloë fungal endophytes are highly desirable in certain pastures as the resulting mutualistic association has the capacity to confer agronomic benefits (such as invertebrate pest deterrence) largely due to fungal produced secondary metabolites (e.g., alkaloids). In this study, we investigated T2 segregating populations derived from two independent transformation events expressing diacylglycerol acyltransferase (DGAT) and cysteine oleosin (CO) genes designed to increase foliar lipid and biomass accumulation. These populations were either infected with Epichloë festucae var. lolii strain AR1 or Epichloë sp. LpTG-3 strain AR37 to examine relationships between the introduced trait and the endophytic association. Here we report on experiments designed to investigate if expression of the DGAT + CO trait in foliar tissues of perennial ryegrass could negatively impact the grass-endophyte association and vice versa. Both endophyte and plant characters were measured under controlled environment and field conditions.ResultsExpected relative increases in total fatty acids of 17–58% accrued as a result of DGAT + CO expression with no significant difference between the endophyte-infected and non-infected progeny. Hyphal growth in association with DGAT + CO expression appeared normal when compared to control plants in a growth chamber. There was no significant difference in mycelial biomass for both strains AR1 and AR37, however, Epichloë-derived alkaloid concentrations were significantly lower on some occasions in the DGAT + CO plants compared to the corresponding null-segregant progenies, although these remained within the reported range for bioactivity.ConclusionsThese results suggest that the mutualistic association formed between perennial ryegrass and selected Epichloë strains does not influence expression of the host DGAT + CO technology, but that endophyte performance may be reduced under some circumstances. Further investigation will now be required to determine the preferred genetic backgrounds for introgression of the DGAT + CO trait in combination with selected endophyte strains, as grass host genetics is a major determinant to the success of the grass-endophyte association in this species.

Engineering Yarrowia lipolytica for sustainable ricinoleic acid production: A pathway to free fatty acid synthesis

Ricinoleic acid (C18:1-OH, RA) is a valuable hydroxy fatty acid with versatile applications. The current industrial source of RA relies on the hydrolysis of castor bean oil. However, the coexistence of the toxic compound ricin and the unstable supply of this plant have led to an exploration of promising alternatives: generating RA in heterologous plants or microorganisms. In this study, we engineered the oleaginous yeast Yarrowia lipolytica to produce RA in the form of free fatty acids (FFA). First, we overexpressed fungal Δ12 oleate hydroxylase gene (CpFAH12) from Claviceps purpurea while deleting genes related to fatty acid degradation (MEF1 and PEX10) and oleic acid desaturation (FAD2). Since Δ12 oleate hydroxylase converts oleic acid (C18:1) located at the sn-2 position of phosphatidylcholine (PC), we next focused on increasing the PC pool containing oleic acid. This objective was achieved thorough implementing metabolic engineering strategies designed to enhance the biosynthesis of PC and C18 fatty acids. To increase the PC pool, we redirected the flux towards phospholipid biosynthesis by deleting phosphatidic acid phosphatase genes (PAH1 and APP1) and diacylglycerol acyltransferase gene (DGA1), involved in the production of diacylglycerol and triacylglycerol, respectively. Furthermore, the PC biosynthesis via the CDP-DAG pathway was enhanced through the overexpression of CDS1, PSD1, CHO2, and OPI3 genes. Subsequently, to increase the oleic acid content within PC, we overexpressed the heterologous fatty acid elongase gene (MaC16E) involved in the conversion of C16 to C18 fatty acids. As RA production titer escalated, the produced RA was mainly found in the FFA form, leading to cell growth inhibition. The growth inhibition was mitigated by inducing RA secretion via Triton X-100 treatment, a process that simultaneously amplified RA production by redirecting flux towards RA synthesis. The final engineered strain JHYL-R146 produced 2.061 g/L of free RA in a medium treated with 5% Triton X-100, constituting 74% of the total FFAs produced. Generating free RA offers the added benefit of bypassing the hydrolysis stage required when employing castor bean oil as an RA source. This achievement represents the highest level of RA synthesis from glucose reported thus far, underscoring the potential of Y. lipolytica as a host for sustainable RA production.

Effects of nitrogen starvation on TAG biosynthesis genes expression in Chlorella vulgaris

Microalgal oils and lipids are the potential sources of sustainable industrial products for pharmaceuticals, nutraceuticals, and cosmeceuticals. However, the production cost of microalgal-based products is still expensive and hinders their marketability. Therefore, research has been focusing on increasing microalgae's oil and lipids content to be economically reasonable. Nutrient stresses were often used to enhance oils and lipids production in microalgae. In this study, the microalga Chlorella vulgaris was exposed to nitrogen starvation for 21 days to examine the effect of nitrogen removal on cell density, total oil content, fatty acids composition, and the expression of two triacylglycerols (TAG) biosynthetic genes, glycerol-3-phosphate acyltransferase (GPAT) and diacylglycerol acyltransferase (DGAT). The results showed that the C. vulgaris cells grew extremely slowly (p<0.05) under nitrogen starvation conditions. However, despite the growth outcome, the nitrogen starvation increased (p<0.05) total oil contents on days 3, 11 and 14 relatives to control. Nitrogen starvation also stimulated (p<0.05) the production of saturated fatty acids (SFA). The primary fatty acids detected were C16:0, C18:0, C18:1, C18:2, C18:3 and C20:0. The effect of nitrogen starvation on the expression of TAG biosynthetic genes, GPAT and DGAT genes were enumerated using real-time PCR. Both GPAT and DGAT were downregulated in this study. Interestingly, the buildup of C18:2 and C18:3 was positively linked with GPAT expression, demonstrating that GPAT affected the synthesis of polyunsaturated fatty acids (PUFA) in nitrogen-starved circumstances. This suggests that the GPAT gene may be altered to increase PUFA in microalgae, notably C18:2 and C18:3.

Genome-Wide Identification and Analysis of the DGAT Gene Family in Lindera glauca and Expression Analysis during Fruit Development Stages

Diacylglycerol acyltransferase (DGAT) is a vital and sole rate-limiting enzyme involved in triacylglycerol synthesis. Identifying DGAT genes in Lindera glauca is essential for studying lipid metabolism pathways and developing novel oil crops with enhanced value. In the study reported in this paper, 15 LgDGAT family genes were first obtained from the L. glauca genome via bioinformatics analysis. We comprehensively analyzed their chromosome distribution, gene structure, subcellular localization, promoter prediction, phylogenetic relationships, tissue-specific expression, and expression patterns during different stages of fruit development. Our findings revealed that LgDGATs can be classified into DGAT1, DGAT2, DGAT3, and WSD (wax ester synthase/acyl-CoA: diacylglycerol acyltransferase) subfamilies distributed across chromosome 3, 5, 6, 8 and 11. LgDGATs’ promoter region showed abundant elements linked to the light response and plant hormone response. Forms of LgDGAT1, LgDGAT2, and LgDGAT3 were primarily expressed in the early and late phases of fruit development, indicating their potential function in the growth and development of L. glauca, particularly in oil accumulation. Conversely, LgWSDs exhibited predominant expression in stems and leaves. This paper elucidates the gene structure and expression patterns of LgDGATs, providing a theoretical foundation for understanding the functionality of DGAT genes in Lindera species.

Heterogeneous diacylglycerol acyltransferase expression enhances lipids and PUFA in Chlorella species

AbstractAlgae have been explored for renewable energy, nutraceuticals, and value‐added products. However, low lipid yield is a significant impediment to its commercial viability. Genetic engineering can improve the fatty acid profile of algae without compromising its growth. This study introduced the diacylglycerol acyltransferase (BnDGAT) gene from Brassica napus into Chlorella sorokiniana‐I, a fast‐growing and thermotolerant natural strain isolated from wastewater, which increased its intracellular lipid accumulation. Hygromycin‐resistant cells were selected, and enhanced green florescence protein fluorescence was used to distinguish pure transgenic cell lines from mixed cultures. Compared to the wild type, BnDGAT expression in transgenic C. sorokiniana‐I caused a threefold increase in non‐polar lipid and a twofold increase in polyunsaturated fatty acids. Nile red staining reaffirmed the presence of higher intracellular lipid bodies in transgenic cells. There was a substantial alteration in the fatty acid profile of transgenic alga expressing BnDGAT. The non‐essential omega 9 (C18: 1) fatty acid decreased (5%–7% from 18%), while alpha‐linolenic acid, an essential omega 3 fatty acid (C18: 3), was increased (23%–24% from 11%). This study substantiates a valuable strategy for enhancing essential omega‐3 fatty acids and neutral lipids to improve its nutritional value for animal feed. The increased lipid productivity should reduce the cost of producing fatty acid methyl esters (FAME). Improved FAME quality should address the clouding issues in cold regions.

Alterations in energy metabolism of Rhodnius prolixus induced by Trypanosoma rangeli infection

Trypanosoma rangeli is a protozoan parasite that infects triatomines and mammals in the Americas, producing mixed infections with Trypanosoma cruzi, the etiological agent of Chagas disease. The former parasite is not pathogenic to humans, but has different levels of pathogenicity, as well as causing physiological and behavioral alterations, to its invertebrate hosts. In this study, we measured locomotory activity, and the glyceride accumulation profile in the hemolymph and fat body, as well as the expression of key genes related to triglyceride metabolism, of Rhodnius prolixus nymphs infected with T. rangeli. We found that the locomotory activity of the insects was correlated with the amount of triglycerides in the fat body. Infected nymphs had increased activity when starved, and also had an accumulation of glycerides in the fat body and hemolymph. These alterations were also associated with a higher expression of the diacylglycerol acyltransferase, lipophorin and lipophorin receptor genes in the fat body. We infer that T. rangeli is able to alter the energetic processes of its invertebrate host, in order to increase the availability of lipids to the parasite, which, in turn modifies the activity levels of the insect. These alterations are discussed with regard to their potential to increase the transmission rate of the parasite.

Association of DGAT1 Gene Related to Flavor, Odor, Cholesterol, and Mineral in Indonesian Sheep

Diacylglycerol acyltransferase 1 (DGAT1) is a potential candidate gene for improving Indonesian lamb’s quality and nutrient value. The study aimed to identify the diversity of the DGAT1 gene with SNP g.8539 CT and its relation to Indonesian lamb's flavor and odor, cholesterol, and mineral. Total of 254 ten to twelve months old sheep consisted of 20 Javanese fat-tail sheep (JFTS), 107 Javanese thin-tail sheep (JTTS), 10 Garut composite sheep (GCS), 10 Compass agrinak sheep (CAS), 10 Barbados cross sheep (BCS), 20 Garut sheep (GS), 27 Jonggol sheep (JS), and 50 Jambi local sheep (JLS). One hundred sheep were used to analyze the association of the DGAT1 gene with flavor and odor content, cholesterol, and mineral. The diversity of DGAT1|AluI was analyzed with the PCR-RFLP method. The association of the DGAT1 gene with the nutritional value of meat was analyzed using the GLM (General Linear Model) method. The results showed that the DGAT gene was polymorphic in JTTS, GS, and JFTS and monomorphic in CAS, BCS, JLS, and GCS. CC and CT genotypes were found in JTTS, GS, and JFTS. SNP g.8539 CT of DGAT1 gene had a significant association (P0.05) with flavor and odor, 4-Ethyloctanoic Acid (EOA). However, the DGAT1 gene had no significant association (P0.05) with cholesterol and mineral. The DGAT1 gene might be marker-assisted selection for improving lamb flavor and odor in Indonesian sheep.

Integrative lipidomics profile uncovers the mechanisms underlying high-level α-linolenic acid accumulation in Paeonia rockii seeds.

Tree peony (Paeonia rockii) is an excellent woody oilseed crop, known for its high α-linolenic acid (ALA, ~45%) content, which is of great value for human health. However, the mechanisms underlying this high-level ALA accumulation in tree peony seeds are poorly understood. In this study, we evaluated the dynamic changes in the lipidomic profile of P. rockii seeds during development. A total of 760 lipid molecules were identified in P. rockii seeds; triacylglycerol (TAG) lipid molecules showed the highest abundance and diversity, both increasing during seed development. Particularly, ALA was the predominant fatty acid at the TAG sn-3 position. We further characterized two diacylglycerol acyltransferase (DGAT) genes and three phospholipid:diacylglycerol acyltransferase (PDAT) genes involved in the transfer of fatty acids to the TAG sn-3 position. Gene expression and subcellular localization analyses suggested that PrDGATs and PrPDATs may function as endoplasmic reticulum-localized proteins in seed TAG biosynthesis. In vitro functional complementation analysis showed different substrate specificities, with PrPDAT2 having a specific preference for ALA. Multiple biological assays demonstrated that PrDGAT1, PrDGAT2, PrPDAT1-2, and PrPDAT2 promote oil synthesis. Specifically, PrPDAT2 leads to preferential ALA in the oil. Our findings provide novel functional evidence of the roles of PrDGAT1 and PrPDAT2, which are potential targets for increasing the ALA yield in tree peony and other oilseed crops.

Slr2103, a homolog of type-2 diacylglycerol acyltransferase genes, for plastoquinone-related neutral lipid synthesis and NaCl-stress acclimatization in a cyanobacterium, Synechocystis sp. PCC 6803.

A cyanobacterium, Synechocystis sp. PCC 6803, contains a lipid with triacylglycerol-like TLC mobility but its identity and physiological roles remain unknown. Here, on ESI-positive LC-MS2 analysis, it is shown that the triacylglycerol-like lipid (lipid X) is related to plastoquinone and can be grouped into two subclasses, Xa and Xb, the latter of which is esterified by 16:0 and 18:0. This study further shows that a Synechocystis homolog of type-2 diacylglycerol acyltransferase genes, slr2103, is essential for lipid X synthesis: lipid X disappears in a Synechocystis slr2103-disruptant whereas it appears in an slr2103-overexpressing transformant (OE) of Synechococcus elongatus PCC 7942 that intrinsically lacks lipid X. The slr2103 disruption causes Synechocystis cells to accumulate plastoquinone-C at an abnormally high level whereas slr2103 overexpression in Synechococcus causes the cells to almost completely lose it. It is thus deduced that slr2103 encodes a novel acyltransferase that esterifies 16:0 or 18:0 with plastoquinone-C for the synthesis of lipid Xb. Characterization of the slr2103-disruptant in Synechocystis shows that slr2103 contributes to sedimented-cell growth in a static culture, and to bloom-like structure formation and its expansion by promoting cell aggregation and floatation upon imposition of saline stress (0.3-0.6 M NaCl). These observations provide a basis for elucidation of the molecular mechanism of a novel cyanobacterial strategy to acclimatize to saline stress, and one for development of a system of seawater-utilization and economical harvesting of cyanobacterial cells with high-value added compounds, or blooming control of toxic cyanobacteria.

Metabolic Composition and Quality Traits of Polygonatum cyrtonema Hua from Different Germplasms and Age Sections Based on Widely Targeted Metabolomics Analysis.

Polygonatum rhizomes are rich in various compounds with many biological activities and are widely used in functional foods and pharmaceutical products. In order to screen for superior Polygonatum cyrtonema Hua (P. cyrtonema) germplasm and also to elucidate the nutritional and medicinal values of rhizomes, the metabolic composition and quality traits of rhizomes from different germplasms and age sections of P. cyrtonema were analysed by widely targeted metabolomics, and the molecular mechanism of triacylglycerol synthesis was explored. The results showed that the different germplasms and age sections of P. cyrtonema were rich in different nutritional and medicinal components. Of these, the broad-leaved green stem (GK) germplasm is rich in polysaccharides, alkaloids, and lipids; the pointed-leaved green stem (JL) germplasm is rich in flavonoids, steroids, and amino acids, while the pointed-leaved purple stem (JZ) germplasm contains more phenolic acids. The one-year (AT) age section is rich in polysaccharides, steroids, organic acids, and lipids; the three years (CT) age section contains more flavonoids, alkaloids, and amino acid metabolites. Lipids were significantly enriched in the broad-leaved green stem germplasm and the one-year age section. Interestingly, the highest accumulation of triacylglycerols, an important component of lipids, was also found in the GK germplasm and the AT age section. Nineteen, 14, and 13 members of the glycerol-3-phosphate acyltransferase (GPAT), lysophosphatidic acid acyltransferase (LPAT), and diacylglycerol acyltransferase (DGAT) gene families, respectively, involved in triacylglycerol synthesis were also identified. The quantitative real-time PCR (qRT-PCR) results further suggested that the differentially expressed PcDGAT1, PcDGAT2.4, PcGPAT9.1, PcLPAT2.9, and PcLPAT4.3 genes may play important roles in triacylglycerol synthesis in P. cyrtonema. Therefore, this study provides a new theoretical reference for product development and the breeding of new varieties of Polygonatum species.

Association of Single Nucleotide Polymorphism in the DGAT1 Gene with the Fatty Acid Composition of Cows Milked Once and Twice a Day.

A single nucleotide polymorphism (SNP) rs109421300 of the diacylglycerol acyltransferase 1 (DGAT1) on bovine chromosome 14 is associated with fat yield, fat percentage, and protein percentage. This study aimed to investigate the effect of SNP rs109421300 on production traits and the fatty acid composition of milk from cows milked once a day (OAD) and twice a day (TAD) under New Zealand grazing conditions. Between September 2020 and March 2021, 232 cows from a OAD herd and 182 cows from a TAD herd were genotyped. The CC genotype of SNP rs109421300 was associated with significantly (p < 0.05) higher fat yield, fat percentage, and protein percentage, and lower milk and protein yields in both milking frequencies. The CC genotype was also associated with significantly (p < 0.05) higher proportions of C16:0 and C18:0, higher predicted solid fat content at 10 °C (SFC10), and lower proportions of C4:0 and C18:1 cis-9 in both milking frequencies. The association of SNP with fatty acids was similar in both milking frequencies, with differences in magnitudes. The SFC10 of cows milked OAD was lower than cows milked TAD for all three SNP genotypes suggesting the suitability of OAD milk for producing easily spreadable butter. These results demonstrate that selecting cows with the CC genotype is beneficial for New Zealand dairy farmers with the current payment system, however, this would likely result in less spreadable butter.

Genome-wide identification and expression analysis of diacylglycerol acyltransferase genes in soybean (Glycine max).

Soybean (Glycine max) is a major protein and vegetable oil source. In plants, diacylglycerol acyltransferase (DGAT) can exert strong flux control, which is rate-limiting for triacylglycerol biosynthesis in seed oil formation. Here, we identified soybean DGAT genes via a bioinformatics method, thereby laying a solid foundation for further research on their function. Based on our bioinformatics analyses, including gene structure, protein domain characteristics, and phylogenetic analysis, 26 DGAT putative gene family members unevenly distributed on 12 of the 20 soybean chromosomes were identified and divided into the following four groups: DGAT1, DGAT2, WS/DGAT, and cytoplasmic DGAT. The Ka/Ks ratio of most of these genes indicated a significant positive selection pressure. DGAT genes exhibited characteristic expression patterns in soybean tissues. The differences in the structure and expression of soybean DGAT genes revealed the diversity of their functions and the complexity of soybean fatty acid metabolism. Our findings provide important information for research on the fatty acid metabolism pathway in soybean. Furthermore, our results will help identify candidate genes for potential fatty acid-profile modifications to improve soybean seed oil content. This is the first time that in silico studies have been used to report the genomic and proteomic characteristics of DGAT in soybean and the effect of its specific expression on organs, age, and stages.

Analysis of oil synthesis pathway in Cyperus esculentus tubers and identification of oleosin and caleosin genes

The tubers of the widely distributed Cyperus esculentus are rich in oil, and therefore, the plant is considered to have a high utilization value in the vegetable oil industry. Oleosins and caleosins are lipid-associated proteins found in oil bodies of seeds; however oleosins and caleosins genes have not been identified in C. esculentus. In this study, we performed transcriptome sequencing and lipid metabolome analysis of C. esculentus tubers at four developmental stages to obtain the information on their genetic profile, expression trends, and metabolites in oil accumulation pathways. Overall, 120,881 non-redundant unigenes and 255 lipids were detected; 18 genes belonged to the acetyl-CoA carboxylase (ACC), malonyl-CoA:ACP transacylase (MCAT), β-ketoacyl-ACP synthase (KAS), and fatty acyl-ACP thioesterase (FAT) gene families involved in fatty acid biosynthesis, and 16 genes belonged to the glycerol-3-phosphate acyltransferase (GPAT), diacylglycerol acyltransferase 3 (DGAT3), phospholipid:diacylglycerol acyltransferase (PDAT), FAD2, and lysophosphatidic acid acyltransferase (LPAAT) gene families playing important roles in triacylglycerol synthesis. We also identified 9 oleosin- and 21 caleosin-encoding genes in C. esculentus tubers. These results provide detailed information on the C. esculentus transcriptional and metabolic profiles, which can be used as reference for the development of strategies to increase oil content in C. esculentus tubers.

Mutation c.-379 C>T in DGAT1 affects intramyocellular lipid content by altering MYOD1 binding affinity.

Intramuscular fat (IMF) is one of the most important indexes of pork taste quality. Diacylglycerol acyltransferase 1 (DGAT1), belonging to the acyl-coenzyme A: DGAT enzymes family, is a rate-limiting enzyme responsible for the final step of triglyceride (TG) synthesis. It is involved in TG storage in skeletal muscle; however, the underlying mechanism is not well understood. This study aimed to uncover functional mutations that can influence DGAT1 expression and consequently affect IMF deposition in pork. Two experimental groups containing individuals with high and low IMF content (6.23 ± 0.20 vs. 1.25 ± 0.05, p < 0.01) were formed from 260 Duroc × Large White × Yorkshire (D × L × Y) cross-bred pigs. A novel SNP c.-379 C>T was uncovered in the DGAT1 gene using comparative sequencing with pool DNA of high- and low-IMF groups. The IMF content of CT genotype individuals (3.19 ± 0.11%) was higher than that of CC genotype individuals (2.86 ± 0.11%) when analyzing 260 D × L × Y pigs (p < 0.05). The DGAT1 expression levels revealed a significant positive correlation with IMF content (r=0.33, p < 0.01). Luciferase assay revealed that the DGAT1 promoter with the c.-379 T allele has a higher transcription activity than that bearing the C allele in C2C12 myoblast cells, but not in 3T3-L1 pre-adipocytes. Online prediction followed by chromatin immunoprecipitation-polymerase chain reaction assay confirmed that myogenic determination factor 1 (MYOD1) binds to the DGAT1 promoter with the c.-379 C allele but not the T allele. In vitro experiments demonstrated that MYOD1 represses DGAT1 transcription and lipogenesis. As a muscle-specific transcription factor, MYOD1 can inhibit the transcription of DGAT1 with the c.-379 C allele in muscle cells. However, in the absence of MYOD1 binding to the mutated DGAT1 promoter with the c.-379 T allele, DGAT1 expresses at a higher level in the muscle cells of the c.-379 T genotype, leading to more intramyocellular lipid accumulation than in the muscle cells of the c.-379 C genotype. The SNP c.-379 C>T in the promoter region of the DGAT1 gene provides a promising molecular marker for improving pork IMF content without affecting other fat depots.

Genome-Wide Identification, Classification, and Expression Analyses of the CsDGAT Gene Family in Cannabis sativa L. and Their Response to Cold Treatment.

Hempseed is a nutrient-rich natural resource, and high levels of hempseed oil accumulate within hemp seeds, consisting primarily of different triglycerides. Members of the diacylglycerol acyltransferase (DGAT) enzyme family play critical roles in catalyzing triacylglycerol biosynthesis in plants, often governing the rate-limiting step in this process. As such, this study was designed to characterize the Cannabis sativa DGAT (CsDGAT) gene family in detail. Genomic analyses of the C. sativa revealed 10 candidate DGAT genes that were classified into four families (DGAT1, DGAT2, DGAT3, WS/DGAT) based on the features of different isoforms. Members of the CsDGAT family were found to be associated with large numbers of cis-acting promoter elements, including plant response elements, plant hormone response elements, light response elements, and stress response elements, suggesting roles for these genes in key processes such as development, environmental adaptation, and abiotic stress responses. Profiling of these genes in various tissues and varieties revealed varying spatial patterns of CsDGAT expression dynamics and differences in expression among C. sativa varieties, suggesting that the members of this gene family likely play distinct functional regulatory functions CsDGAT genes were upregulated in response to cold stress, and significant differences in the mode of regulation were observed when comparing roots and leaves, indicating that CsDGAT genes may play positive roles as regulators of cold responses in hemp while also playing distinct roles in shaping the responses of different parts of hemp seedlings to cold exposure. These data provide a robust basis for further functional studies of this gene family, supporting future efforts to screen the significance of CsDGAT candidate genes to validate their functions to improve hempseed oil composition.

Metabolomics and Transcriptomics Provide Insights into Lipid Biosynthesis in the Embryos of Walnut (Juglans regia L.).

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.

Polimorfismo dos genes DGAT e LEP e sua associação com características de carcaça e perfil lipídico da carne de bovinos nelore

ABSTRACT The objective of this study was to evaluate the association of polymorphisms in the diacylglycerol acyltransferase ( DGAT ) and leptin ( LEP ) genes with the performance, carcass characteristics, meat quality, and lipid profile of Nellore cattle. A total of 100 intact male Nelore cattle were used to analyze the performance, carcass, physicochemical and centesimal composition, and fatty acid profile of beef. To identify the polymorphisms, the PCR–single-strand conformation polymorphism (SSCP) technique was applied to genomic DNA extracted from muscle tissue. The SSCP technique revealed the presence of four band patterns for the DGAT gene (AC, AD, AE and BB) with five alleles (A, B, C, D and E). For the LEP gene, five band patterns (AA, AB, AC, BB and BC) with three alleles (A, B and C) were observed. For the LEP gene, the AB genotype was associated with higher backfat thickness and ribs weight, while the BB genotype was associated with lower ribs yield; higher hindquarter yield was associated with AC and BB genotypes. Higher contents of C17:0, C18:0 and lower contents of C18:2ω6C, total polyunsaturated fatty acids, total ω6 and ratio of polyunsaturated and saturated fatty acids (PUFA/SFA) were verified for the AC genotype of the LEP gene. The AC and AA genotypes of the LEP gene were associated with higher means of C15:0 and C18:1ω9t. For the DGAT gene, the highest C24:0 content was associated with the AE genotype and the lowest with the AD and BB genotypes. Polymorphisms in the DGAT and LEP genes influence carcass parameters and the lipid profile of the meat of Nellore cattle.

The effects of FASN and DGAT1 gene polymorphism on colostrum and milk fatty acid composition of Charolais cows and growth in Charolais calves

Fatty acid composition of milk has become an important trait in dairy production, but there has not been a large amount of research on milk fat composition in beef cows. The aim of this study was to evaluate the effects of polymorphisms in the fatty acid synthase (FASN) and acyl-CoA diacylglycerol acyltransferase (DGAT1) gene on milk and colostrum fatty acid composition, and their direct (calf) and indirect (cow/mother) relationships with calf birth weight and weight gain over 14 days. Eight Charolais cows and eight calves were genotyped using the PCR-RFLP method. The cows’ milk and colostrum fatty acid profiles and their calves’ weight at birth and 14 day weight gain were analysed. In the colostrum, cows with DGAT1 genotype KA had a significantly higher content of C4:0 and lower C10:0, and with FASN diplotype TW/AR a tendency for higher C14:0 and C16:0 colostrum FA content. In the milk, Charolais cows with diplotype TW/AR tended to have higher C14:1, C16:0 and C16:1, but lower C18:0 content. At the same time, no associations were found between DGAT1 genotypes and the fatty acid composition of milk. There were also no significant associations found between the studied SNPs and the calf’s birth weight and weight gain over 14 days, although calves with DGAT1 KA genotype tended to have higher birth weight.