共查询到20条相似文献,搜索用时 15 毫秒
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Pham AT Lee JD Shannon JG Bilyeu KD 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,123(5):793-802
The alteration of fatty acid profiles in soybean to improve soybean oil quality has been a long-time goal of soybean researchers.
Soybean oil with elevated oleic acid is desirable because this monounsaturated fatty acid improves the nutrition and oxidative
stability of soybean oil compared to other oils. In the lipid biosynthetic pathway, the enzyme fatty acid desaturase 2 (FAD2)
is responsible for the conversion of oleic acid precursors to linoleic acid precursors in developing soybean seeds. Two genes
encoding FAD2-1A and FAD2-1B were identified to be expressed specifically in seeds during embryogenesis and have been considered
to hold an important role in controlling the seed oleic acid content. A total of 22 soybean plant introduction (PI) lines
identified to have an elevated oleic acid content were characterized for sequence mutations in the FAD 2-1A and FAD2-1B genes. PI 603452 was found to contain a deletion of a nucleotide in the second exon of FAD2-1A. These important SNPs were used in developing molecular marker genotyping assays. The assays appear to be a reliable and
accurate tool to identify the FAD 2-1A and FAD2-1B genotype of wild-type and mutant plants. PI 603452 was subsequently crossed with PI 283327, a soybean line that has a mutation
in FAD2-1B. Interestingly, soybean lines carrying both homozygous insertion/deletion mutation (indel) FAD2-1A alleles and mutant FAD2-1B alleles have an average of 82–86% oleic acid content, compared to 20% in conventional soybean, and low levels of linoleic
and linolenic acids. The newly identified indel mutation in the FAD2-1A gene offers a simple method for the development of high oleic acid commercial soybean varieties. 相似文献
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Jinlei Shi Yingping Cao Xiaorong Fan Min Li Yaofeng Wang Feng Ming 《Molecular breeding : new strategies in plant improvement》2012,29(3):743-757
A full-length cDNA clone of OsFAD2, which encodes a Δ-12 fatty acid desaturase, the key enzyme for the conversion of oleic acid (18:1) into linoleic acid (18:2),
was isolated from rice (Oryza sativa ssp. japonica) leaves. The deduced amino acid sequence of OsFAD2 displayed three histidine boxes characteristic of all membrane-bound desaturases, and possessed a C-terminal signal for endoplasmic
reticulum retention. Phylogenetic analysis showed that OsFAD2 is grouped within plant housekeeping FAD2 sequences. Expression analysis by real-time PCR showed that the gene is expressed
in all tissues of rice tested, including root, seed, stem, and leaf. In situ hybridization showed that OsFAD2 mRNA accumulated in leaf mesophyll cells and in root epidermis cells when exposed to 15°C for 4 days in dark conditions.
When OsFAD2 was expressed in Saccharomyces cerevisiae, the cells could convert oleic acid to linoleic acid, which wild-type yeast cells cannot do, suggesting that the isolated
gene encoded a functional FAD2 enzyme. Heterologous expression of OsFAD2 enhanced the yeast cells’ cold tolerance capacity compared to wild-type yeast. OsFAD2 was also shown to be a highly active desaturase when expressed in Xenopus oocytes. In addition, when the OsFAD2 gene was transferred into an Arabidopsis thaliana
fad2-1 mutant, it effectively restored wild-type fatty acid composition and growth characteristics. Stress tolerance and light regulatory
elements were identified in the predicted promoter of the OsFAD2 gene. Exogenously supplied hormone affected the level of FAD2 mRNA accumulation, accompanied by a change of content of di-unsaturated fatty acid species in rice leaves. Furthermore, OsFAD2 enhanced tolerance to low temperature when overexpressed in rice at the vegetative stage. More importantly, the 35S::OsFAD2
plants showed significantly enhanced cold tolerance at the reproductive stage, increasing grain yield by 46% over controls
in the greenhouse under cold conditions. These results indicated that OsFAD2 is involved in fatty acid desaturation and maintenance
of the membrane lipids balance in cells, and could improve the tolerance of yeast and rice to low temperature stress. 相似文献
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As a new α-linolenic acid (ALA) resource, there has been little known about the relationship between expression levels of fatty acid desaturase (FAD) genes during seed development and fatty acid (FA) composition in herbaceous peony (Paeonia lactiflora Pall.). In this study, oil content and FA composition of nine cultivars were measured at four different stages during seed development. Moreover, five genes including PlFAD2-1, PlFAD2-2, PlFAD3-2, PlFAD6 and PlFAD7 related to the ALA biosynthesis were isolated. Furthermore, the relative expression levels of these genes in seeds were investigated in two cultivars, that is, ‘PL1’ and ‘PL2’ with higher and lower ALA content, respectively. The results showed that oil content was from 17.03 ± 0.15 to 24.51 ± 0.15%; 15 kinds of FA were detected. However, the relative content of ALA was decreased during seed development. Although, the genes PlFAD2-1, PlFAD2-2, PlFAD3-2, PlFAD6 and PlFAD7 were all expressed during the seed development, the expression levels varied significantly. Most of the genes were expressed strongly in the early stage but weakly in the late stage except PlFAD6. Moreover, expression level of gene PlFAD2-2 was the highest while that of PlFAD7 was lowest at S1. In addition, the relative expression level of genes in ‘PL1’ (high ALA content) was higher than those in ‘PL2’ (low ALA content) during the early stage of the seed development apart from gene PlFAD6. This study provides a reliable theoretical basis for improving the contents of ALA by means of genetic engineering in the herbaceous peony seed oil. 相似文献
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Xiaoyuan Chi Qingli Yang Yandu Lu Jinyan Wang Qingfen Zhang Lijuan Pan Mingna Chen Yanan He Shanlin Yu 《Plant Molecular Biology Reporter》2011,29(4):769-783
Fatty acid desaturases can introduce double bonds into the hydrocarbon chains of fatty acids to produce unsaturated fatty
acids. In the present study, 29 full-length desaturase genes were identified from soybean genome by a thorough annotation
exercise. A comprehensive analysis was performed to characterize phylogeny, chromosomal locations, structures, conserved motifs,
and expression patterns of those genes. The soybean genes were phylogenetically clustered into nine subfamilies with the Arabidopsis counterparts, FAB2, FAD2, FAD3, FAD5, FAD6, FAD7, FAD8, SLD1, and DES1. Twenty-nine desaturase genes were found to be distributed on at least 15 of the 20 soybean chromosomes. The gene structures
and motif compositions were considerably conserved among the subfamilies. The majority of desaturase genes showed specific
temporal and spatial expression patterns across different tissues and developmental stages based on microarray data analyses.
The study may provide new insights into the origin and evolution of fatty acid biosynthesis pathways in higher plants. Additionally,
the characterization of desaturases from soybean will lead to the identification of additional genes for genetic modification
of plants to produce nutritionally important fatty acids. 相似文献
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Improved soybean oil quality by targeted mutagenesis of the fatty acid desaturase 2 gene family 总被引:2,自引:0,他引:2
William Haun Andrew Coffman Benjamin M. Clasen Zachary L. Demorest Anita Lowy Erin Ray Adam Retterath Thomas Stoddard Alexandre Juillerat Frederic Cedrone Luc Mathis Daniel F. Voytas Feng Zhang 《Plant biotechnology journal》2014,12(7):934-940
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Jihua Cheng E. M. J. Salentijn Bangquan Huang F. A. Krens A. C. Dechesne R. G. F. Visser E. N. van Loo 《Molecular breeding : new strategies in plant improvement》2013,32(3):517-531
Crambe (Crambe abyssinica Hochst ex. R. E. Fries) is an ideal crop for industrial oil production because of its high erucic acid content (C22:1, approx. 60 %) in its seed oil. The value of crambe oil can be improved by increasing C22:1 content or reducing polyunsaturated fatty acids (PUFA). The FAD2 gene plays a critical role in PUFA biosynthesis. To identify targets for breeding, we characterized FAD2 in crambe for copy number and expression profile. Seven copies of FAD2 were detected in allohexaploid crambe. Three genes (CaFAD2-C1, -C2 and -C3) were expressed in multiple tissues, including root, seedling, leaf, flower, bud and developing seeds. In developing seeds, the expression of these genes was upregulated with CaFAD2-C3, being expressed predominantly with a peak at 20 days after pollination. This gene is therefore a promising candidate gene for determining PUFA levels in seed oil. Four other FAD2 genes were considered to be “pseudo-genes” as they harbour internal stop codons and were not expressed. Among the six crambe varieties with consistent variation in oil composition, no nucleotide polymorphisms were found in the CaFAD2-C1, -C2 and -C3 genes. In seeds at 30 days after pollination, statistically significant expression level polymorphisms for only one gene, CaFAD2-C2, was found among the varieties. However, although significantly different, the difference in expression was small and did not explain the variation in oil composition. Given the absence of genetic variation in CaFAD2 genes in crambe breeding lines, breeding for high erucic acid content calls for a molecular breeding approach whereby mutations are chemically induced to increase the genetic variation. 相似文献
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Zhong Wang Mingxun Chen Tianlong Chen Lijie Xuan Zhilan Li Xue Du Longhua Zhou Guoping Zhang Lixi Jiang 《The Plant journal : for cell and molecular biology》2014,77(5):757-769
TRANSPARENT TESTA2 (TT2) regulates the biosynthesis of proanthocyanidins in the seed coat of Arabidopsis. We recently found that TT2 also participates in inhibition of fatty acid (FA) biosynthesis in the seed embryo. However, the mechanism by which TT2 suppresses the accumulation of seed FA remains unclear. In this study, we show that TT2 is expressed in embryos at an early developmental stage. TT2 is directly bound to the regulatory region of FUSCA3 (FUS3), and mediates the expression of numerous genes in the FA biosynthesis pathway. These genes include BCCP2, CAC2, MOD1 and KASII, which encode proteins involved in the initial steps of FA chain formation, FAD2 and FAD3, which are responsible for FA desaturation, and FAE1, which catalyzes very‐long‐chain FA elongation. Loss of function of TT2 results in reduced expression of GLABRA2 but does not cause a significant reduction in the mucilage attached to the seed coats, which competes with FA for photosynthates. TT2 is expressed in both maternal seed coats and embryonic tissues, but proanthocyanidins are only found in wild‐type seed coats and not in embryonic tissues. The amount of proanthocyanidins in the seed coat is negatively correlated with the amount of FAs in the embryo. 相似文献
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One of the goals in oilseed rape programs is to develop genotypes producing oil with low linolenic acid content (C18:3, ≤3%).
Low linolenic mutant lines of canola rapeseed were obtained via chemical mutagenesis at the Plant Breeding and Acclimatization Institute – NRI, in Poznan, Poland, and allele-specific SNP
markers were designed for monitoring of two statistically important single nucleotide polymorphisms detected by SNaPshot analysis
in two FAD3 desaturase genes, BnaA.FAD3 and BnaC.FAD3, respectively. Strong negative correlation between the presence of mutant alleles of the genes and linolenic acid content
was revealed by analysis of variance. In this paper we present detailed characteristics of the markers by estimation of the
additive and dominance effects of the FAD3 genes with respect to particular fatty acid content in seed oil, as well as by calculation of the phenotypic variation of
seed oil fatty acid composition accounted by particular allele-specific marker. The obtained percentage of variation in fatty
acid composition was considerable only for linolenic acid content and equaled 35.6% for BnaA.FAD3 and 39.3% for BnaC.FAD3, whereas the total percentage of variation in linolenic acid content was 53.2% when accounted for mutations in both genes
simultaneously. Our results revealed high specificity of the markers for effective monitoring of the wild-type and mutated
alleles of the Brassica napus FAD3 desaturase genes in the low linolenic mutant recombinants in breeding programs. 相似文献
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Laura Saa Arrate Jaureguibeitia Eneko Largo María J. Llama Juan L. Serra 《Applied microbiology and biotechnology》2010,86(1):201-211
Phenol hydroxylase that catalyzes the conversion of phenol to catechol in Rhodococcus erythropolis UPV-1 was identified as a two-component flavin-dependent monooxygenase. The two proteins are encoded by the genes pheA1 and pheA2, located very closely in the genome. The sequenced pheA1 gene was composed of 1,629 bp encoding a protein of 542 amino acids, whereas the pheA2 gene consisted of 570 bp encoding a protein of 189 amino acids. The deduced amino acid sequences of both genes showed high
homology with several two-component aromatic hydroxylases. The genes were cloned separately in cells of Escherichia coli M15 as hexahistidine-tagged proteins, and the recombinant proteins His6PheA1 and His6PheA2 were purified and its catalytic activity characterized. His6PheA1 exists as a homotetramer of four identical subunits of 62 kDa that has no phenol hydroxylase activity on its own. His6PheA2 is a homodimeric flavin reductase, consisting of two identical subunits of 22 kDa, that uses NAD(P)H in order to reduce
flavin adenine dinucleotide (FAD), according to a random sequential kinetic mechanism. The reductase activity was strongly
inhibited by thiol-blocking reagents. The hydroxylation of phenol in vitro requires the presence of both His6PheA1 and His6PheA2 components, in addition to NADH and FAD, but the physical interaction between the proteins is not necessary for the
reaction. 相似文献
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Shuangyi Bai Steven Engelen Peter Denolf James G. Wallis Katherine Lynch Jesse D. Bengtsson Michel Van Thournout Boris Haesendonckx John Browse 《The Plant journal : for cell and molecular biology》2019,98(1):33-41
Producing healthy, high‐oleic oils and eliminating trans‐fatty acids from foods are two goals that can be addressed by reducing activity of the oleate desaturase, FAD2, in oilseeds. However, it is essential to understand the consequences of reducing FAD2 activity on the metabolism, cell biology and physiology of oilseed crop plants. Here, we translate knowledge from studies of fad2 mutants in Arabidopsis (Arabidopsis thaliana) to investigate the limits of non‐GMO approaches to maximize oleic acid in the seed oil of canola (Brassica napus), a species that expresses three active FAD2 isozymes. A series of hypomorphic and null mutations in the FAD2.A5 isoform were characterized in yeast (Saccharomyes cerevisiae). Then, four of these were combined with null mutations in the other two isozymes, FAD2.C5 and FAD2.C1. The resulting mutant lines contained 71–87% oleic acid in their seed oil, compared with 62% in wild‐type controls. All the mutant lines grew well in a greenhouse, but in field experiments we observed a clear demarcation in plant performance. Mutant lines containing less than 80% oleate in the seed oil were indistinguishable from wild‐type controls in growth parameters and seed oil content. By contrast, lines with more than 80% oleate in the seed oil had significantly lower seedling establishment and vigor, delayed flowering and reduced plant height at maturity. These lines also had 7–11% reductions in seed oil content. Our results extend understanding of the B. napusFAD2 isozymes and define the practical limit to increasing oil oleate content in this crop species. 相似文献
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Shoko Okada Xue-Rong Zhou Katherine Damcevski Nerida Gibb Craig Wood Mats Hamberg Victoria S. Haritos 《The Journal of biological chemistry》2013,288(45):32405-32413
Plants in the Santalaceae family, including the native cherry Exocarpos cupressiformis and sweet quandong Santalum acuminatum, accumulate ximenynic acid (trans-11-octadecen-9-ynoic acid) in their seed oil and conjugated polyacetylenic fatty acids in root tissue. Twelve full-length genes coding for microsomal Δ12 fatty acid desaturases (FADs) from the two Santalaceae species were identified by degenerate PCR. Phylogenetic analysis of the predicted amino acid sequences placed five Santalaceae FADs with Δ12 FADs, which include Arabidopsis thaliana FAD2. When expressed in yeast, the major activity of these genes was Δ12 desaturation of oleic acid, but unusual activities were also observed: i.e. Δ15 desaturation of linoleic acid as well as trans-Δ12 and trans-Δ11 desaturations of stearolic acid (9-octadecynoic acid). The trans-12-octadecen-9-ynoic acid product was also detected in quandong seed oil. The two other FAD groups (FADX and FADY) were present in both species; in a phylogenetic tree of microsomal FAD enzymes, FADX and FADY formed a unique clade, suggesting that are highly divergent. The FADX group enzymes had no detectable Δ12 FAD activity but instead catalyzed cis-Δ13 desaturation of stearolic acid when expressed in yeast. No products were detected for the FADY group when expressed recombinantly. Quantitative PCR analysis showed that the FADY genes were expressed in leaf rather than developing seed of the native cherry. FADs with promiscuous and unique activities have been identified in Santalaceae and explain the origin of some of the unusual lipids found in this plant family. 相似文献
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