Inhibition by long-chain acyl-CoAs of glucose 6-phosphate metabolism in plastids isolated from developing embryos of oilseed rape (Brassica napus L.).
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ABSTRACT:
SUBMITTER: Johnson PE
PROVIDER: S-EPMC1221047 | biostudies-other | 2000 May
REPOSITORIES: biostudies-other
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Project description:Addition of oleoyl-CoA (1 microM), or other acyl-CoA thioesters with a chain length of C(16) or greater, to oilseed rape plastids (Brassica napus L.) inhibited the rate of D-glucose 6-phosphate (Glc6P) uptake by 70% after 2 min. The IC(50) value for oleoyl-CoA inhibition of the transporter was approx. 0.2-0.3 microM. Inhibition was alleviated by the addition of acyl-CoA binding protein (ACBP) or BSA at slightly higher concentrations. Oleic acid (5-25 microM), Tween 40 (10 microM), Triton-X 100 (10 microM) and palmitoylcarnitine (5 microM) had no effect on Glc6P uptake. The uptake of [1-(14)C]Glc6P occurred in exchange for P(i), 3-phosphoglycerate or Glc6P at a typical rate of 30 nmol Glc6P/min per unit of glyceraldehyde-3-phosphate dehydrogenase (NADP(+)). The K(m(app)) of the Glc6P transporter for Glc6P was 100 microM. Neither CoA (0.3 mM) nor ATP (3 mM) inhibited Glc6P uptake, but the transporter was inhibited by 72% when ATP and CoA were added together. This inhibition was attributable to the synthesis of acyl-CoA thioesters, predominantly oleoyl-CoA and palmitoyl-CoA, by long-chain fatty acid-CoA ligase (EC 6.2.1.3) from endogenous fatty acids in the plastid preparations. Acyl-CoA thioesters did not inhibit the uptake of [2-(14)C]pyruvate or D-[1-(14)C]glucose into plastids. In vivo quantities of oleoyl-CoA and other long-chain acyl-CoA thioesters were lower than those for ACBP in early cotyledonary embryos, 0.7+/-0.2 pmol/embryo and 2.2+/-0.2 pmol/embryo respectively, but in late cotyledonary embryos quantities of long-chain acyl-CoA thioesters were greater than ACBP, 3+/-0.4 pmol/embryo and 1.9+/-0.2 pmol/embryo respectively.
| S-EPMC1221485 | biostudies-other
Project description:Rapeseed (Brassica napus), the second most important oilseed crop globally, originated from an interspecific hybridization between B. rapa and B. oleracea. After this genome collision, B. napus underwent extensive genome restructuring, via homoeologous chromosome exchanges, resulting in widespread segmental deletions and duplications. Illicit pairing among genetically similar homoeologous chromosomes during meiosis is common in recent allopolyploids like B. napus, and post-polyploidization restructuring compounds the difficulties of assembling a complex polyploid plant genome. Specifically, genomic rearrangements between highly similar chromosomes are challenging to detect due to the limitation of sequencing read length and ambiguous alignment of reads. Recent advances in long read sequencing technologies provide promising new opportunities to unravel the genome complexities of B. napus by encompassing breakpoints of genomic rearrangements with high specificity. Moreover, recent evidence revealed ongoing genomic exchanges in natural B. napus, highlighting the need for multiple reference genomes to capture structural variants between accessions. Here we report the first long-read genome assembly of a winter B. napus cultivar. We sequenced the German winter oilseed rape accession 'Express 617' using 54.5x of long reads. Short reads, linked reads, optical map data and high-density genetic maps were used to further correct and scaffold the assembly to form pseudochromosomes. The assembled Express 617 genome provides another valuable resource for Brassica genomics in understanding the genetic consequences of polyploidization, crop domestication, and breeding of recently-formed crop species.
| S-EPMC7202327 | biostudies-literature
Project description:With dwindling available agricultural land, concurrent with increased demand for oil, there is much current interest in raising oil crop productivity. We have been addressing this issue by studying the regulation of oil accumulation in oilseed rape (Brassica napus L). As part of this research we have carried out a detailed lipidomic analysis of developing seeds. The molecular species distribution in individual lipid classes revealed quite distinct patterns and showed where metabolic connections were important. As the seeds developed, the molecular species distributions changed, especially in the period of early (20days after flowering, DAF) to mid phase (27DAF) of oil accumulation. The patterns of molecular species of diacylglycerol, phosphatidylcholine and acyl-CoAs were used to predict the possible relative contributions of diacylglycerol acyltransferase (DGAT) and phospholipid:diacylglycerol acyltransferase to triacylglycerol production. Our calculations suggest that DGAT may hold a more important role in influencing the molecular composition of TAG. Enzyme selectivity had an important influence on the final molecular species patterns. Our data contribute significantly to our understanding of lipid accumulation in the world's third most important oil crop.
| S-EPMC5791847 | biostudies-other
Project description:Breeding crops with ideal root system architecture for efficient absorption of phosphorus is an important strategy to reduce the use of phosphate fertilizers. To investigate genetic variants leading to changes in root system architecture, 405 oilseed rape cultivars were genotyped with a 60K Brassica Infinium SNP array in low and high P environments. A total of 285 single-nucleotide polymorphisms were associated with root system architecture traits at varying phosphorus levels. Nine single-nucleotide polymorphisms corroborate a previous linkage analysis of root system architecture quantitative trait loci in the BnaTNDH population. One peak single-nucleotide polymorphism region on A3 was associated with all root system architecture traits and co-localized with a quantitative trait locus for primary root length at low phosphorus. Two more single-nucleotide polymorphism peaks on A5 for root dry weight at low phosphorus were detected in both growth systems and co-localized with a quantitative trait locus for the same trait. The candidate genes identified on A3 form a haplotype 'BnA3Hap', that will be important for understanding the phosphorus/root system interaction and for the incorporation into Brassica napus breeding programs.
| S-EPMC5737433 | biostudies-other
Project description:To identify marker genes that are specific for N starvation-induced leaf senescence and suitable to detect cultivar differences at early senescence stages prior to chlorophyll loss, the transcriptomes of leaves of two B. napus cultivars differing in stay-green characteristics and N efficiency were analysed four days after senescence induction by the senescence inducers N starvation, leaf shading and leaf detaching.
2015-01-15 | GSE60108 | GEO
Project description:Intense selection for specific seed qualities in winter oilseed rape breeding has had an inadvertent negative influence on seed germination performance. In a panel of 215 diverse winter oilseed rape varieties spanning over 50 years of breeding progress in winter-type rapeseed, we found that low seed erucic acid content and reduced seed glucosinolate content were significantly related with prolonged germination time. Genome-wide association mapping revealed that this relationship is caused by linkage drag between important loci for seed quality and germination traits. One QTL for mean germination time on chromosome A09 co-localized with significant but minor QTL for both seed erucic acid and seed glucosinolate content. This suggested either potential pleiotropy or close linkage of minor factors influencing all three traits. Therefore, a reduction in germination performance may be due to inadvertent co-selection of genetic variants associated with 00 seed quality that have a negative influence on germination. Our results suggest that marker-assisted selection of positive alleles for mean germination time within the modern quality pool can help breeders to maintain maximal germination capacity in new 00-quality oilseed rape cultivars.
| S-EPMC5891602 | biostudies-literature
Project description:Branch architecture is an important factor influencing rapeseed planting density, mechanized harvest, and yield. However, its related genes and regulatory mechanisms remain largely unknown. In this study, branch angle (BA) and branch dispersion degree (BD) were used to evaluate branch architecture. Branch angle exhibited a dynamic change from an increase in the early stage to a gradual decrease until reaching a stable state. Cytological analysis showed that BA variation was mainly due to xylem size differences in the vascular bundle of the branch junction. The phenotypic analysis of 327 natural accessions revealed that BA in six environments ranged from 24.3° to 67.9°, and that BD in three environments varied from 4.20 cm to 21.4 cm, respectively. A total of 115 significant loci were detected through association mapping in three models (MLM, mrMLM, and FarmCPU), which explained 0.53%-19.4% of the phenotypic variations. Of them, 10 loci were repeatedly detected in different environments and models, one of which qBAD.A03-2 was verified as a stable QTL using a secondary segregation population. Totally, 1066 differentially expressed genes (DEGs) were identified between branch adaxial- and abaxial- sides from four extremely large or small BA/BD accessions through RNA sequencing. These DEGs were significantly enriched in the pathways related to auxin biosynthesis and transport as well as cell extension such as indole alkaloid biosynthesis, other glycan degradation, and fatty acid elongation. Four known candidate genes BnaA02g16500D (PIN1), BnaA03g10430D (PIN2), BnaC03g06250D (LAZY1), and BnaC06g20640D (ARF17) were identified by both GWAS and RNA-seq, all of which were involved in regulating the asymmetric distribution of auxins. Our identified association loci and candidate genes provide a theoretical basis for further study of gene cloning and genetic improvement of branch architecture.
| S-EPMC9650407 | biostudies-literature
Project description:Key messageSix stable QTL for resistance against L. maculans (phoma stem canker) have been identified by QTL × environment interaction analysis using data from five winter oilseed rape field experiments. Phoma stem canker, caused by Leptosphaeria maculans, is a disease of worldwide importance on oilseed rape (Brassica napus). Quantitative trait loci (QTL)-mediated resistance against L. maculans in B. napus is considered to be race non-specific and potentially durable. Identification and evaluation of QTL for resistance to L. maculans is important for breeding oilseed rape cultivars with durable resistance. An oilseed rape mapping population was used to detect QTL for resistance against L. maculans in five winter oilseed rape field experiments under different environments. A total of 17 QTL involved in 'field' quantitative resistance against L. maculans were detected and collectively explained 51% of the phenotypic variation. The number of QTL detected in each experiment ranged from two to nine and individual QTL explained 2-25% of the phenotypic variation. QTL × environment interaction analysis suggested that six of these QTL were less sensitive to environmental factors, so they were considered to be stable QTL. Markers linked to these stable QTL will be valuable for selection to breed for effective resistance against L. maculans in different environments, which will contribute to sustainable management of the disease.
| S-EPMC4703627 | biostudies-literature
Project description:Evaluating the effects of agroclimatic constraints on winter oilseed rape (WOSR) yield can facilitate the development of agricultural mitigation and adaptation strategies. In this study, we investigated the relationship between the WOSR yield and agroclimatic factors using the yield data collected from Agricultural Yearbook and field experimental sites, and the climate dataset from the meteorological stations in Hubei province, China. Five agroclimatic indicators during WOSR growth, such as ≥0 °C accumulated temperature (AT-0), overwintering days (OWD), precipitation (P), precipitation at an earlier stage (EP) and sunshine hours (S), were extracted from twelve agroclimatic indices. The attainable yield for the five yield-limiting factors ranged from 2638 kg ha-1 (EP) to 3089 kg ha-1 (AT-0). Farmers (Y farm ) and local agronomists (Y exp ) have achieved 63% and 86% of the attainable yield (Y att ), respectively. The contribution of optimum fertilization to narrow the yield gap (NY exp ) was 52% for the factor P, which was remarkably lower than the mean value (63%). Overall, the precipitation was the crucial yield-limiting agroclimatic factor, and restricted the effect of optimizing fertilization. The integrated data suggest that agricultural strategies of mitigation and adaptation to climatic variability based on different agroclimatic factors are essential for improving the crop yield.
| S-EPMC5552806 | biostudies-other
Project description:BACKGROUND:Increasing the productivity of rapeseed as one of the widely cultivated oil crops in the world is of upmost importance. As flowering time and plant architecture play a key role in the regulation of rapeseed yield, understanding the genetic mechanism underlying these traits can boost the rapeseed breeding. Meristem identity genes are known to have pleiotropic effects on plant architecture and seed yield in various crops. To understand the function of one of the meristem identity genes, APETALA1 (AP1) in rapeseed, we performed phenotypic analysis of TILLING mutants under greenhouse conditions. Three stop codon mutant families carrying a mutation in Bna.AP1.A02 paralog were analyzed for different plant architecture and seed yield-related traits. RESULTS:It was evident that stop codon mutation in the K domain of Bna.AP1.A02 paralog caused significant changes in flower morphology as well as plant architecture related traits like plant height, branch height, and branch number. Furthermore, yield-related traits like seed yield per plant and number of seeds per plants were also significantly altered in the same mutant family. Apart from phenotypic changes, stop codon mutation in K domain of Bna.AP1.A02 paralog also altered the expression of putative downstream target genes like Bna.TFL1 and Bna.FUL in shoot apical meristem (SAM) of rapeseed. Mutant plants carrying stop codon mutations in the COOH domain of Bna.AP1.A02 paralog did not have a significant effect on plant architecture, yield-related traits or the expression of the downstream targets. CONCLUSIONS:We found that Bna.AP1.A02 paralog has pleiotropic effect on plant architecture and yield-related traits in rapeseed. The allele we found in the current study with a beneficial effect on seed yield can be incorporated into rapeseed breeding pool to develop new varieties.
| S-EPMC6310979 | biostudies-literature