Acid Content In Rapeseed Research Articles

Selection of Agronomic Parameters and Construction of Prediction Models for Oleic Acid Contents in Rapeseed Using Hyperspectral Data

High oleic acid oilseed rape is a hot research area in the development of functional oilseed rape. At present, the model of predicting the oleic acid content in rapeseed at the early growth stage based on hyperspectral technology lacks a mechanistic explanation. In this study, based on the data collected at the 5–6 leaf stage of oilseed rape, a one-dimensional linear regression prediction model of the oleic acid content in leaves (x) and the oleic acid content in rapeseed (y) was constructed with the regression equation y = 1.83x + 75.26, and the R2, RMSE, and RPD of the testing set were 0.96, 0.23%, and 4.86, respectively. Then, a support vector regression prediction model of the spectral standard normal transformed feature parameters and the oleic acid content in leaves was constructed, and the R2, RMSE, and RPD of the testing set were 0.74, 0.21%, and 2.01, respectively. Finally, the sensitive parameter transfer model for the prediction of “spectral standard normal transform feature—oleic acid content in leaves—oleic acid content in rapeseed” was validated, and the R2, RMSE, and RPD of the full sample test were 0.71, 0.54%, and 0.54, respectively. The results show that although the accuracy of the prediction model after the introduction of the agronomic parameters was reduced compared with the performance of direct prediction by using spectra, the oleic acid content in oilseed rape leaves, as an important intermediate variable, could better explain the relationship between the reflection spectrum of the leaf and the oleic acid content in rapeseed. This study provides a theoretical basis and technical support for hyperspectral remote sensing technology in the quality prediction of rapeseed.

Safety evaluation of FAD2 RNAi transgenic Brassica napus L. based on microbial diversity and metabonomic analysis.

Oleic acid desaturase (FAD2) is the key enzyme that produces polyunsaturated fatty acids in rapeseed (Brassica napus L), which is one of the main oil crops. RNA interference (RNAi) is an emerging technique that provides new opportunities for the generation of new traits in plants. To increase oleic acid content and reduce linoleic and linolenic acid content in rapeseed, we constructed an ihpRNA plant expression vector of the FAD2 gene and obtained transgenic plants for multiple generations by stable inheritance. In this study, third-generation transgenic plants (T3), seventh-generation transgenic plants (T7), and wild-type plants (WT) were used. The differences in microbial community diversity between transgenic plants and wild-type plants and the up- and downregulation of rhizosphere metabolite contents were investigated. In conclusion, the results showed that the soil microbial community structure was stable, the general microbial community structure was not changed by the transgenic rhizosphere exudates, and no significant harmful root exudate of transgenic rapeseed on the environment was found through the microbial community and metabolomics analysis. This work may provide an understanding of the impact of RNAi on plant metabolites and a safety evaluation method for transgenic plants and a reference for rapeseed breeding.

GWAS and co-expression network combination uncovers multigenes with close linkage effects on the oleic acid content accumulation in Brassica napus

BackgroundStrong artificial and natural selection causes the formation of highly conserved haplotypes that harbor agronomically important genes. GWAS combination with haplotype analysis has evolved as an effective method to dissect the genetic architecture of complex traits in crop species.ResultsWe used the 60 K Brassica Infinium SNP array to perform a genome-wide analysis of haplotype blocks associated with oleic acid (C18:1) in rapeseed. Six haplotype regions were identified as significantly associated with oleic acid (C18:1) that mapped to chromosomes A02, A07, A08, C01, C02, and C03. Additionally, whole-genome sequencing of 50 rapeseed accessions revealed three genes (BnmtACP2-A02, BnABCI13-A02 and BnECI1-A02) in the A02 chromosome haplotype region and two genes (BnFAD8-C02 and BnSDP1-C02) in the C02 chromosome haplotype region that were closely linked to oleic acid content phenotypic variation. Moreover, the co-expression network analysis uncovered candidate genes from these two different haplotype regions with potential regulatory interrelationships with oleic acid content accumulation.ConclusionsOur results suggest that several candidate genes are closely linked, which provides us with an opportunity to develop functional haplotype markers for the improvement of the oleic acid content in rapeseed.

Identification and Functional Analysis of Two New Mutant BnFAD2 Alleles That Confer Elevated Oleic Acid Content in Rapeseed.

Rapeseed (Brassica napus L.) is a vital oil crop worldwide. High oleic acid content is a desirable quality trait for rapeseed oil, which makes it more beneficial to human health. However, many germplasm resources with high oleic acid content in rapeseed have not been evaluated with regard to their genotypes, making it difficult to select the best strains with this trait for the breeding of high oleic acid rapeseed variety. This work was to explore the gene-regulation mechanism of this trait using a new super-high oleic acid content (∼85%) line N1379T as genetic material. In this study, the sequences of four homologous fatty acid desaturase (BnFAD2) genes were compared between super-high (∼85%, N1379T) and normal (∼63%) oleic acid content lines. Results showed that there were two single-nucleotide polymorphisms (SNPs) in BnFAD2-1 and BnFAD2-2, respectively, which led to the amino acid changes (E106K and G303E) in the corresponding proteins. Functional analysis of both genes in yeast confirmed that these SNPs were loss-of-function mutations, thus limiting the conversion of oleic acid to linoleic acid and resulting in the considerable accumulation of oleic acid. Moreover, two specific cleaved amplified polymorphic sequences (CAPS) markers for the two SNPs were developed to identify genotypes of each line in the F2 and BC1 populations. Furthermore, these two mutant loci of BnFAD2-1 and BnFAD2-2 genes were positively associated with elevated oleic acid levels and had a similar effect with regard to the increase of oleic acid content. Taken together, these two novel SNPs in two different BnFAD2 genes jointly regulated the high oleic acid trait in this special germplasm. The study provided insight into the genetic regulation involved in oleic acid accumulation and highlighted the use of new alleles of BnFAD2-1 and BnFAD2-2 in breeding high oleic acid rapeseed varieties.

Evaluation of RAPD markers as a marker-assisted selection tool for variety type and erucic acid content in rapeseed

Random amplification of polymorphic DNA (RAPD) analysis was performed on twelve rapeseed genotypes from Institute of Field and Vegetable Crops, Novi Sad, Serbia, genepool in order to identify markers that could be used in marker assisted selection (MAS) for different growing type and selection of the varieties with low or zero level of erucic acid. Out of fifteen RAPD markers, three were monomorphic, whereas twelve had polymorphic profiles. Three primers amplified specific fragments in spring varieties. UBC 25 and UBC 191 amplified the fragments of 450 and 750 bp, respectively, in all tested spring varieties, except in JR-NS-36. Primer UBC 72 generated a fragment of 700 bp that was present in all spring varieties. These fragments were not present in any of winter varieties. None of the tested RAPD primers amplified fragment(s) uniquely present either in varieties with or without (0%) erucic acid or with different erucic acid content. Cluster analysis showed a concordance between the position of varieties in the cluster and their pedigree information, but also enabled separation of spring and winter varieties. Contingency analysis confirmed that fragment UBC 72_700 is specific for spring varieties, while for erucic acid content, only moderate association was found with UBC 137_750.

Erucic acid rapeseed: 1. Prospects of improvements

In the current context of boosting production of high erucic acid rapeseed, because of the wide range of its industrial applications, this literature review is designed to provide a general overview of available varieties, current knowledge of plant improvement and paths of developing research to increase competitiveness of varieties with high erucic acid content. A limited market dominated by a few companies, cropping burdens of high erucic acid rapeseed varieties among the majority “00” varieties and the still low erucic acid content in rapeseed, explains the reduced and uncompetitive varietal offers. To improve this situation, new varieties could be developed, thanks to the classical methods of selection and biotechnology.

Differentially Expressed Genes in Oleic Acid Synthesis of <I>Brassica napus</I> by Detected Gene Chip

Oil from rapeseed with high oleic oil content is insensitive to oxidation and long shelf life.In daily diet with high oleic acid oil can reduce low-density lipoprotein cholesterol levels in blood and prevent arteriosclerosis.In addition,high oleic acid content in edible oil is an important fat indicator.Oleic acid can be effectively converted to methyl ester,which is beneficial to produce biodiesel.Oleic acid content in conventional rapeseed is only 17%.However,oleic acid content in low erucic acid rapeseed reaches around 60%.Differential expressed genes of oleic acid have been found in the high oleic acid line(71.71%) and low oleic acid line(55.6%) of Brassica napus by gene chip technique.The results showed that there were 562 differential expressed genes relating to high and low oleic acid contents in rapeseed,among them 194 were up-regulated genes and 368 were down-regulated genes.The up-regulated gene NM_100489 and the down-regulated gene NM_130183 were then taken as the materials.Real time RT-PCR was further used to confirm the results of gene chip,and the results of real time RT-PCR analysis agreed with the results by gene chip.According to the results of gene chip,562 differentially expressed genes were annotated functionally using Go Annotation System.The molecular function of differential expressed genes mainly included catalysis of enzymes,binding,transcriptional regulation,metabolism and others with unknown functions.Some genes related to sugar metabolism and fatty acid synthesis were identified as differential expressed genes.They are pyruvate kinase,fructose diphosphate,acyl transfer/acyl-ACP S lipase,hydrolase acting on ester bond,Δ9 stearoyl acid-N-carrier protein desaturase(ADS1),Δ9 acyl-lipid desaturase 2(ADS2),ω-3 fatty acid desaturation enzymes(fad3) and so on.

Increasing erucic acid content through combination of endogenous low polyunsaturated fatty acids alleles with Ld-LPAAT + Bn-fae1 transgenes in rapeseed (Brassica napus L.)

High erucic acid rapeseed (HEAR) oil is of interest for industrial purposes because erucic acid (22:1) and its derivatives are important renewable raw materials for the oleochemical industry. Currently available cultivars contain only about 50% erucic acid in the seed oil. A substantial increase in erucic acid content would significantly reduce processing costs and could increase market prospects of HEAR oil. It has been proposed that erucic acid content in rapeseed is limited because of insufficient fatty acid elongation, lack of insertion of erucic acid into the central sn-2 position of the triaclyglycerol backbone and due to competitive desaturation of the precursor oleic acid (18:1) to linoleic acid (18:2). The objective of the present study was to increase erucic content of HEAR winter rapeseed through over expression of the rapeseed fatty acid elongase gene (fae1) in combination with expression of the lysophosphatidic acid acyltransferase gene from Limnanthes douglasii (Ld-LPAAT), which enables insertion of erucic acid into the sn-2 glycerol position. Furthermore, mutant alleles for low contents of polyunsaturated fatty acids (18:2 + 18:3) were combined with the transgenic material. Selected transgenic lines showed up to 63% erucic acid in the seed oil in comparison to a mean of 54% erucic acid of segregating non-transgenic HEAR plants. Amongst 220 F(2) plants derived from the cross between a transgenic HEAR line and a non-transgenic HEAR line with a low content of polyunsaturated fatty acids, recombinant F(2) plants were identified with an erucic acid content of up to 72% and a polyunsaturated fatty acid content as low as 6%. Regression analysis revealed that a reduction of 10% in polyunsaturated fatty acids content led to a 6.5% increase in erucic acid content. Results from selected F(2) plants were confirmed in the next generation by analysing F(4) seeds harvested from five F(3) plants per selected F(2) plant. F(3) lines contained up to 72% erucic acid and as little as 4% polyunsaturated fatty acids content in the seed oil. The 72% erucic acid content of rapeseed oil achieved in the present study represents a major breakthrough in breeding high erucic acid rapeseed.

Inheritance and variation of erucic acid content in a transgenic rapeseed (Brassica napus L.) doubled haploid population

Erucic acid (22:1) is a valuable renewable resource for the oleochemical industry. Currently available high erucic acid rapeseed cultivars contain only about 50% erucic acid in the seed oil. A substantial increase of the erucic acid content of the rapeseed oil could increase market prospects. The transgenic line TNKAT, over expressing the rapeseed fatty acid elongase gene (fae1) and expressing the Ld-LPAAT gene from Limnanthes douglasii was crossed with the line 6575-1 HELP (high erucic and low polyunsaturated fatty acid). A from the F1 plants produced population of 90 doubled haploid (DH) lines was tested in a greenhouse with three replicates. Parental lines TNKAT and 6575-1 HELP contained 46 and 50% erucic acid in the seed oil, respectively. In the DH population the erucic acid content ranged between 35 and 59%. The Ld-LPAAT + Bn-fae1.1 transgene showed a 1:1 segregation. The transgenic DH lines contained up to 8% trierucolyglycerol, but surprisingly had a by 2.3% lower erucic acid content compared to the non-transgenic segregants. Results indicated that the ectopically expressed fae1.1 gene may not be functional. The DH population also showed a large quantitative variation for PUFA content ranging from 6 to 28% (TNKAT: 21%, 6575-1 HELP: 8%). Regression analysis showed that in the DH population a 10% reduction in PUFA content led to a 4.2% increase in erucic acid content. Development of locus specific PCR primers for the two resident erucic acid genes fae1.1 (A-genome) and fae1.2 genes (C-genome) of rapeseed allowed sequencing of the respective alleles from TNKAT and 6575-1 HELP. Single nucleotide polymorphisms were only found for the fae1.1 gene. Use of allele specific fae1.1 PCR primers, however, did not reveal a significant effect of the fae1.1 allele from either parent on erucic acid content. The high erucic acid low polyunsaturated fatty acid DH lines and the fae1 locus specific primers developed in the present study should be useful in future studies aimed at increasing erucic acid content in rapeseed.

QTL Identification for Fatty Acid Content in Rapeseed ( Brassica napus L.)

A segregation population BC 1F 1 of rapeseed ( Brassica napus L.), derived from a cross between a low erucic acid content line APL01 and a high erucic acid content variety M083, was used to construct the genetic map and identify auantitave trait loci (QTLs) linked to main fatty acid composition in rapeseed. The genetic map containing 19 linkage groups was constructed with 251 markers of RAPD, SSR, and SRAP. By means of WinQTLCart scanning, 5 QTLs linked to palmitic acid (C16:0) content were identified, which were located on linkage groups N3, N8, N10, and N13, respectively. The main-effect QTLs qPA8-1 and qPA13 linked to palmatic acid content in rapeseed explained 11.31% and 14.47% of the palmitic acid content variation in the segregation population BC 1F 1, respectively. Three QTLs linked to stearic acid (C18:0) content were identified, which were located on the linkage groups N1, N8, and N16. The main-effect QTL qST16 accounted for 12.22% of phenotypic variation. Two QTLs, qOL8 and qOL13, the main-effect QTLs linked to oleic acid (C18:1) content, were located in the region of m11e37b– A0226Ba267 on linkage group N8 and m18e46– m20e25a on N13. These QTLs accounted for 11.73% and 27.14% of phenotypic variation, respectively. Three QTLs linked to linoleic acid (C18:2) content were identified, and the main-effect QTL qLI8-1 accounted for 13.25% of phenotypic variation. Three QTLs, qLN1, qLN8, and qLN11, linked to linolenic acid (C18:3) content, were identified, but they had small effects on C18:3 and could be regarded as minor-QTLs. Four QTLs were linked to eicosenoic acid (C20:1) content, and three of them, qEI8-1, qEI8-2, and qEI13, were main-effect QTLs, accounting for 12.20%, 10.22%, and 11.14% of phenotypic variation, respectively. Two main-effect QTLs linked to erucic acid (C22:1) content, qER8 and qER13, were located in the region of m11e37b– A0226Ba267 on linkage group N8 and A0301Bb398– m18e46 on N13, accounted for 16.74% and 31.32% of phenotypic variation, respectively. The main-effect QTLs linked to fatty acid content, which were located in the region near marker m11e27b on linkage group N8 and m18e46 on linkage group N13, could be used in marker-assisted selection in fatty acid improvement in rapeseed.

Genetic and genotype × environment interaction effects analysis for erucic acid content in rapeseed ( Brassica napus L.)

Genetic main effects and genotype × environment (GE) interaction effects for erucic acid content (EAC) in rapeseed(Brassica napus L.) were analyzed for two year data by using the genetic models and corresponding statistical approaches for quantitative traits of diploid plant seeds. Eight parents were included in adiallel mating design in two environments. It was found that the embryo, cytoplasmic and maternal main effects and their GE interaction effects could simultaneously affect the performance of EAC, especially for the cytoplasmic and maternal effects. Since the amount of genetic main effects from the expression of genes in different genetic systems accounted for about 64.1%of the total genetic effects, EAC of rapeseed was mainly controlled by genetic main effects. The total narrow-sense heritability for EAC was 83.6% with the general heritability being 51.9% and the interaction heritability being 31.7%. It was suggested by the predicted genetic effects, that Tower and Youcai 601 were better than other parents for reducing EAC in rapeseed quality breeding.

A rapeseed FAE1 gene is linked to the E1 locus associated with variation in the content of erucic acid

The synthesis of very long chain fatty acids occurs in the cytoplasm via an elongase complex. A key component of this complex is the β-ketoacyl-CoA synthase, a condensing enzyme which in Arabidopsis is encoded by the FAE1 gene. Two sequences homologous to the FAE1 gene were isolated from a Brassica napus immature embryo cDNA library. The two clones, CE7 and CE8, contain inserts of 1647 bp and 1654 bp, respectively. The CE7 gene encodes a protein of 506 amino acids and the CE8 clone, a protein of 505 amino acids, each having an approximate molecular mass of 56 kDa. The sequences of the two cDNA clones are highly homologous yet distinct, sharing 97% nucleotide identity and 98% identity at the amino acid level. Southern hybridisation showed the rapeseed β-ketoacyl-CoA synthase to be encoded by a small multigene family. Northern hybridisation showed the expression of the rapeseed FAE1 gene(s) to be restricted to the immature embryo. One of the FAE1 genes is tightly linked to the E1 locus, one of two loci controlling erucic acid content in rapeseed. The identity of the second locus, E2, is discussed.

Rapid method for total phenolic acid determination in rapeseed/canola meals

A procedure for the determination of total phenolic acid content in rapeseed/ canola was developed by combining and modifying two currently used methods. It consists of refluxing the sample with acidic acetone, alkaline hydrolysis of esterified phenolic acids followed by acidification, extraction with ethyl acetate/ ethyl ether, and colormetric measurement using Folin-Denis reagent. The method was tested with canola and casein samples spiked with sinapic acid or sinapine bisulphate standards. Recoveries ranging from 95 to 106% were obtained, and the detection limit was determined to be less than 5 mg sinapic acid equivalents per 100 g sample.