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At least 19 recordsLinked to original sources
PubMed1989

Transformation of Brassica napus and Brassica oleracea Using Agrobacterium tumefaciens and the Expression of the bar and neo Genes in the Transgenic Plants.

An efficient and largely genotype-independent transformation method for Brassica napus and Brassica oleracea was established based on neo or bar as selectable marker genes. Hypocotyl explants of Brassica napus and Brassica oleracea cultivars were infected with Agrobacterium strains containing chimeric neo and bar genes. The use of AgNO(3) was a prerequisite for efficient shoot regeneration under selective conditions. Vitrification was avoided by decreasing the water potential of the medium, by decreasing the relative humidity in the tissue culture vessel, and by lowering the cytokinin concentration. In this way, rooted transformed shoots were obtained with a 30% efficiency in 9 to 12 weeks. Southern blottings and genetic analysis of S1-progeny showed that the transformants contained on average between one and three copies of the chimeric genes. A wide range of expression levels of the chimeric genes was observed among independent transformants. Up to 25% of the transformants showed no detectable phosphinotricin acetyltransferase or neomycin phosphotransferase II enzyme activities although Southern blottings demonstrated that these plants were indeed transformed.

Journal Article↗
PubMed1994

Sequence and expression of endogenous S-locus glycoprotein genes in self-compatible Brassica napus.

Brassica napus is an amphidiploid plant which is self-compatible even though it is derived from hybridisation of the self-incompatible species B. oleracea and B. campestris. Experiments were undertaken to establish if S-locus glycoprotein (SLG) genes exist in B. napus and whether these are expressed as in self-incompatible Brassica species. Two different stigma-specific cDNA sequences homologous to SLG genes were obtained from the B. napus cultivar Westar. One of these sequences, SLGWS1, displayed highest homology to class I SLG alleles, whereas the other, SLGWS2, showed greatest homology to class II SLG genes. Both were expressed at high levels in Westar stigmas following a developmental pattern typical of SLG genes in the self-incompatible diploids. We infer that they represent the endogenous SLG genes at the two homologous S-loci. The occurrence of normally expressed SLG genes and its relevance to the self-compatible phenotype of B. napus is discussed.

Alleles↗
PubMed2002

Destiny of a transgene escape from Brassica napus into Brassica rapa.

Transgenic Brassica napus can be easily crossed with wild Brassica rapa. The spread of the transgene to wild species has aroused the general concern about its effect on ecological and agricultural systems. This paper was designated, by means of population genetics, to study the fate of a transgene escape from B. napus to B. rapa. Three models were proposed to survey the change in gene frequency during successive backcross processes by considering selection pressures against aneuploids, against herbicide-susceptible individuals, and by considering A-C intergenomic recombination and the effect of genetic drift. The transmission rate of an A-chromosome gene through an individual to the next generation was 50%, irrespective of the chromosome number; while that of a C-chromosome transgene varied from 8.7% to 39.9%, depending on the chromosome number of the individual used in the backcross. Without spraying herbicide, the frequency of an A-chromosome gene was 50% in the BC(1) generation, and decreased by 50% with the advance of each backcross generation; that of a C-chromosome gene was around 39.9% in BC(1), 7.7% in BC(2), 1.2% in BC(3) and 0.1% in the BC(4) generation. Under the selection pressure against herbicide-susceptible individuals, the frequency of a transgene reached a stable value of about 5.5% within six generations of successive backcrossings. The effect of genetic drift and intergenomic exchange on gene transmission rate was discussed. It is suggested that the transgene integrated on a C-chromosome (or better on a cytoplasm genome) is safer than that on an A-chromosome. The transgenic cultivars should be cultivated rotationally by year(s) with other non-transgenic varieties in order to reduce the transfer of the transgene to wild B. rapa species.

Journal Article↗
PubMed2006

Spontaneous gene flow from rapeseed (Brassica napus) to wild Brassica oleracea.

Research on the environmental risks of gene flow from genetically modified (GM) crops to wild relatives has traditionally emphasized recipients yielding most hybrids. For GM rapeseed (Brassica napus), interest has centred on the 'frequently hybridizing' Brassica rapa over relatives such as Brassica oleracea, where spontaneous hybrids are unreported in the wild. In two sites, where rapeseed and wild B. oleracea grow together, we used flow cytometry and crop-specific microsatellite markers to identify one triploid F1 hybrid, together with nine diploid and two near triploid introgressants. Given the newly discovered capacity for spontaneous introgression into B. oleracea, we then surveyed associated flora and fauna to evaluate the capacity of both recipients to harm cohabitant species with acknowledged conservational importance. Only B. oleracea occupies rich communities containing species afforded legislative protection; these include one rare micromoth species that feeds on B. oleracea and warrants further assessment. We conclude that increased attention should now focus on B. oleracea and similar species that yield few crop-hybrids, but possess scope to affect rare or endangered associates.

Brassica↗
PubMed2004

Identification of the linkage relationship between the flower colour and the content of erucic acid in the resynthesized Brassica napus L.

Brassica napus variety Quantum (yellow flower and low erucic content) as the female parent was crossed with a resynthesized Brassica napus line No. 2127-17 (white flower and high erucic content). The segregation ratios of the flower colour and the erucic acid content were analyzed in the F1, BC1, F2, and DH (doubled haploid) populations. The results indicated that the white flower was dominant over yellow and the erucic acid content was additively inherited. Both traits fit with a monogenic inheritance model, respectively. There were strong evidences to support the linkage relationship between the flower colour and the erucic acid content in the C-genome of B. napus with a recombination frequency of 5.8% in the DH population. The BSA (bulked segregant analysis) strategy was employed to identify random amplified polymorphic DNA (RAPD) marker linked to the genes for the flower colour and erucic acid content in the DH population. Of 685 arbitrary 10-base pair (bp) primers, one primer S92 generated a RAPD marker S92(-1400) that was tightly linked to the genes for the yellow flower and the low erucic acid content in the C-genome of B. napus L. The genetic distance of the genes for yellow flower and the low erucic acid content was 2.2 cM and 5.4 cM from the marker S92(-1400), respectively.

Brassica napus↗
PubMed1999

Low probability of chloroplast movement from oilseed rape (Brassica napus) into wild Brassica rapa.

Pollen-mediated movement of transgenes from transplastomic oilseed rape (Brassica napus) into wild relatives will be avoided if chloroplasts are maternally transmitted. We assess the probability of chloroplast exchange between conventional oilseed rape and wild Brassica rapa to model the future behavior of transplastomic cultivars. Primers specific to cpDNA were used to demonstrate maternal inheritance of chloroplasts in 47 natural hybrids between cultivated B. napus and wild B. rapa. We conclude that there will be no or negligible pollen-mediated chloroplast dispersal from oilseed rape. Transgene introgression could still occur in mixed populations, however, if B. napus acted as the recurrent female parent. Rate of transfer would then depend on the abundance of mixed populations, their persistence as mixtures, and hybridization frequency within stands. A low incidence of sympatry (0.6-0.7%) between wild B. rapa and cultivated B. napus along the river Thames, UK, in 1997 and 1998, suggests mixed stands will form only rarely. Eighteen feral populations of B. napus also showed a strong tendency toward rapid decline in plant number, seed return, and ultimately, extinction within 3 years. Conversely, hybrid production is significant in mixed stands, and the absence of control practices means that oilseed rape will have slightly greater persistence. We infer that some introgression from transplastomic B. napus into B. rapa is inevitable in mixed populations even though such populations will occur infrequently and will tend to lose B. napus plants relatively quickly. Chloroplast exchange will be extremely rare and scattered.

Brassica↗
PubMed2006

Fitness of hybrids between rapeseed (Brassica napus) and wild Brassica rapa in natural habitats.

Fitness of hybrids between genetically modified (GM) crops and wild relatives influences the likelihood of ecological harm. We measured fitness components in spontaneous (non-GM) rapeseed x Brassica rapa hybrids in natural populations. The F1 hybrids yielded 46.9% seed output of B. rapa, were 16.9% as effective as males on B. rapa and exhibited increased self-pollination. Assuming 100% GM rapeseed cultivation, we conservatively predict < 7000 second-generation transgenic hybrids annually in the United Kingdom (i.e. approximately 20% of F1 hybrids). Conversely, whilst reduced hybrid fitness improves feasibility of bio-containment, stage projection matrices suggests broad scope for some transgenes to offset this effect by enhancing fitness.

Brassica napus↗
PubMed1989

Effect of Growth Temperature on the Biosynthesis of Chloroplastic Galactosyldiacylglycerol Molecular Species in Brassica napus Leaves.

Brassica napus leaves developed at low temperature display rapid in situ desaturation of monogalactosyldiacylglycerol (MGDG) fatty acids leading to the production of hexadecatrienoic/linolenic acid. This was shown by radioactivity-tracer experiments to occur via a sequence of desaturations proceeding from the initially synthesized palmitic/oleic acid molecular species to palmitic/linoleic acid, palmitoleic/linoleic acid, hexadecadienoic/linoleic acid, hexadecadienoic/linolenic acid, and finally to hexadecatrienoic/linolenic acid. The results suggest that there is increased activity in all five desaturation steps in leaves developed at low temperatures. Labeling data also indicate that there is another pool of MGDG which is more slowly desaturated before galactosylation to digalactosyldiacylglycerol (DGDG). Our data further suggest that relative rates of galactosylation of chloroplastic and cytosolic MGDG molecular species may regulate the final amounts of chloroplastic and cytosolic MGDG and DGDG in the leaf. We have proposed a model for chloroplastic biosynthesis and desaturation of galactosyldiacylglycerols in the leaves of Brassica napus, a 16:3 plant.

Journal Article↗
PubMed2001

Expression of the S receptor kinase in self-compatible Brassica napus cv. Westar leads to the allele-specific rejection of self-incompatible Brassica napus pollen.

Expression of an S receptor kinase (SRK910) transgene in the self-compatible Brassica napus cv. Westar conferred on the transgenic pistil the ability to reject pollen from the self-incompatible Brassica napus W1 line, which carries the S910 allele. In one of the SRK transgenic lines, 1C, virtually no seeds were produced when the transgenic pistils were pollinated with W1 pollen (Mean number of seeds per pod = 1.22). This response was specific to the W1 pollen since pollen from a different self-incompatible Brassica napus line (T2) and self-pollinations were fully compatible. Westar plants expressing an S locus glycoprotein transgene (SLG910) did not show any self-incompatibility response towards W1 pollen. Transgenic Westar plants resulting from crosses between the 1C SRK transgenic line and three SLG910 transgenic lines were also tested for rejection of W1 pollen. The additional expression of the SLG910 transgene in the SRK910 transgenic plants did not cause any significant further reduction in seed production (Mean seeds/pod = 1.04) or have any detectable effects on the number of pollen grains that adhered to the pistil. Thus, while the allele-specific SLG gene was previously reported to have an enhancing effect on the self-incompatibility response, no evidence for such a role was found in this study.

Alleles↗
PubMed1997

Recombinant antibody fragments that detect enoyl acyl carrier protein reductase in Brassica napus.

Purified Brassica napus enoyl acyl carrier protein reductase (ENR) was used to select specific antibodies from a library of antibody fragments, single-chain Fv (scFv), displayed on filamentous phage. Analysis of the selected clones by BstNI fingerprinting and nucleotide sequencing showed that the scFv were derived from three different human VH germline genes. The binding specificities were confirmed by Western blots and ELISA. The scFv preparations reacted with B. napus ENR, but not with beta-keto reductase, nor enoyl reductase from Escherichia coli. Analysis of fragments generated by CNBr treatment indicates that the scFv 3.13 recognized an epitope located within the N-terminal 80 amino acids of the enzyme molecule. The scFv were used to detect ENR directly in extracts of B. napus seeds.

Acyl Carrier Protein↗
PubMed2005

Intersubgenomic heterosis in seed yield potential observed in a new type of Brassica napus introgressed with partial Brassica rapa genome.

This paper reports the observation on the intersubgenomic heterosis for seed yield among hybrids between natural Brassica napus (A(n)A(n)C(n)C(n)) and a new type of B. napus with introgressions of genomic components of Brassica rapa (A(r)A(r)). This B. napus was selected from the progeny of B. napus x B. rapa and (B. napus x B. rapa) x B. rapa based on extensive phenotypic and cytological observation. Among the 129 studied partial intersubgenomic hybrids, which were obtained by randomly crossing 13 lines of the new type of B. napus in F(3) or BC(1)F(3) to 27 cultivars of B. napus from different regions as tester lines, about 90% of combinations exceeded the yield of their respective tester lines, whereas about 75% and 25% of combinations surpassed two elite Chinese cultivars, respectively. This strong heterosis was further confirmed by reevaluating 2 out of the 129 combinations in a successive year and by surveying hybrids between 20 lines of the new type of B. napus in BC(1)F(5) and its parental B. napus in two locations. Some DNA segments from B. rapa were identified with significant effects on seed yield and yield components of the new type of B. napus in BC(1)F(5) and intersubgenomic hybrids in positive or negative direction. It seems that the genomic components introgressed from B. rapa contributed to improvement of seed yield of rapeseed.

Analysis of Variance↗
PubMed2005

Large scale purification of rapeseed proteins (Brassica napus L.).

Rapeseed (Brassica napus L.) cruciferin (12S globulin), napin (2S albumin) and lipid transfer proteins (LTP) were purified at a multi-g scale. The procedure developed was simple, rather fast and resolutive; it permitted the recovery of these proteins with a good yield, such as 40% for cruciferin and 18% for napin. Nanofiltration eliminated the major phenolic compounds. The remaining protein fraction was fractionated by cation exchange chromatography (CEC) on a streamline SP-XL column in alkaline conditions. The unbound neutral cruciferin was polished by size exclusion chromatography. The alkaline napin isoforms and LTP, adsorbed on the beads, were eluted as a whole fraction and further separated by an other CEC step at acidic pH. Napins were polished by hydrophobic interaction chromatography (HIC). The fractions were characterized by reverse phase HPLC, electrophoresis, N-terminal sequencing and mass spectrometry. All the fractions contained less than 5% of impurities.

2S Albumins, Plant↗
PubMed2003

Uptake and distribution of sinigrin in microspore derived embryos of Brassica napus L.

In Brassica napus, glucosinolates are transported from all parts of the plant into the embryo during seed development. In this study we describe the uptake of the alkenyl glucosinolate sinigrin by microspore derived embryos from high and low glucosinolate genotypes. Microspore derived embryos develop completely isolated from maternal tissues unlike zygotic embryos, which contains glucosinolates transported into the embryo synthesised in the vegetative tissues. The sinigrin in the culture medium was almost completely absorbed by the embryos after three days of culture. The embryos of high and low glucosinolate genotypes were equally capable of absorbing sinigrin from the medium. A significant increase in different alkenyl glucosinolates following feeding of sinigrin suggests induction of biosynthetic enzymes in the embryos. Following excess feeding of sinigrin, we found a strong uptake against a concentration gradient and stable accumulation by the embryos. The glucosinolate was detected in single dissected cotyledons by a photometric test and by HPLC. This test could potentially be useful for screening mutants defective in glucosinolate uptake into the embryo.

Biological Transport↗
PubMed2005

Identification of prior candidate genes for Sclerotinia local resistance in Brassica napus using Arabidopsis cDNA microarray and Brassica-Arabidopsis comparative mapping.

Arabidopsis cDNA arrays were used to screen the local-defense-associated genes in oilseed rape (Brassica napus L.) at the challenge of Sclerotinia sclerotiorum. 61 genes with two-fold expression changes were screened out from the local tissue around the necrosis. Among them, 36 unique genes were up-regulated and 25 unique genes were down-regulated. RT-PCR and Northern blot results were consistent with the array results, suggesting Arabidopsis arrays were useful for transcriptional profiling of B. napus genes. Some of these genes were located in the interval of some QTLs for Sclerotinia resistance in B. napus by Brassica-Arabidopsis comparative mapping. These genes may have priority to be pursued for more intensive research.

Arabidopsis↗
PubMed2006

Down-regulation of prostate specific antigen in LNCaP cells by flavonoids from the pollen of Brassica napus L.

The pollen of Brassica napus L. has been used in China to treat benign prostatic hyperplasia (BPH) for over decades. In this study, the pollen of Brassica napus L. was extracted successively with chloroform, ethyl acetate and ethanol. The ethyl acetate extract showed strong activity in decreasing the secretion of prostate specific antigen (PSA) in LNCaP cells as compared to two other extracts, measured by ELISA with finasteride as positive control in the assay. Five flavonoids were subsequently isolated from the active extract using bioassay-guided fractionation. They were Naringenin (1); Luteolin (2); Kaempferol (3); Kaempferol 3-(3-E-p-coumaroyl-alpha-L-rhamnopyranoside) (4); and Kaempferol 3-(2,3-di-E-p-coumaroyl-alpha-L-rhamnopyranoside) (5). All these compounds inhibited PSA secretion significantly, with IC50 values in the range of 5-50 microM. Compounds 2, 4 and 5 showed moderate cytotoxicity to LNCaP cells within the active concentration range, while compounds 1 and 3 showed no cytotoxicity. Further studies on the mechanism action of these compounds were performed by evaluating their activation of estrogen receptor (ER) and antagonistic activities on androgen receptor (AR) in cell-based reporter gene assays. All compounds described here were first isolated from the pollen of Brassica napus L.

Brassica napus↗
PubMed1996

Molecular characterization of the S locus in two self-incompatible Brassica napus lines.

In Brassica species, self-incompatibility has been mapped genetically to a single chromosomal location. In this region, there are two closely linked genes coding for the S locus glycoprotein (SLG) and S locus receptor kinase (SRK). They appear to comprise the pistil component of the self-incompatibility reaction. SLG and SRK are thought to recognize an unknown pollen component on the incompatible pollen, and the gene encoding this pollen component must also be linked to the SLG and SRK genes. To further our understanding of self-incompatibility, the chromosomal region carrying the SLG and SRK genes has been studied. The physical region between the SLG-910 and the SRK-910 genes in the Brassica napus W1 line was cloned, and a search for genes expressed in the anther revealed two additional S locus genes located downstream of the SLG-910 gene. Because these two genes are novel and are conserved at other S alleles, we designated them as SLL1 and SLL2 (for S locus-linked genes 1 and 2, respectively). The SLL1 gene is S locus specific, whereas the SLL2 gene is not only present at the S locus but is also present in other parts of the genomes in both self-incompatible and self-compatible Brassica ssp lines. Expression of the SLL1 gene is only detectable in anthers of self-incompatible plants and is developmentally regulated during anther development, whereas the SLL2 gene is expressed in anthers and stigmas in both self-incompatible and self-compatible plants, with the highest levels of expression occurring in the stigmas. Although SLL1 and SLL2 are linked to the S locus region, it is not clear whether these genes function in self-incompatibility or serve some other cellular roles in pollen-pistil functions.

Amino Acid Sequence↗
PubMed2000

Fatty acid breakdown in developing embryos of Brassica napus L.

Developing Brassica napus embryos are primarily concerned with the accumulation of storage products, namely oil, starch and protein. The presence of fatty acid catabolic pathways in the background of this biosynthetic activity was investigated. Enzymes involved in the process of lipid mobilization, such as malate synthase and isocitrate lyase, are detectable towards the late stages of embryo development. [(14)C]Acetate feeding experiments also reveal that fatty acid catabolism becomes increasingly functional as the embryo matures.

Acetates↗
PubMed2002

Drought stress affects chloroplast lipid metabolism in rape (Brassica napus) leaves.

Rape (Brassica napus L. var. Bienvenue) is a 16:3 plant which contains predominantly prokaryotic species of monogalactosyldiacylglycerol i.e. sn-1 C18, sn-2 C16 (C18/C16 MGDG). Rape plants were exposed to a restricted water supply for 12 days. Under drought conditions, considerable changes in lipid metabolism were observed. Drought stress provoked a decline in leaf polar lipids, which is mainly due to a decrease in MGDG content. Determination of molecular species in phosphatidylcholine (PC) and MGDG indicated that the prokaryotic molecular species of MGDG (C18/C16) decreased after drought stress while the eukaryotic molecular species (C18/C18) remained stable. Drought stress had different effects on two key enzymes of PC and MGDG synthesis. The in vitro activity of MGDG synthase (EC. 2.4.1.46) was reduced in drought stressed plants whereas cholinephosphotransferase (EC. 2.7.8.2) activity was not affected. Altogether these results suggest that the prokaryotic pathway leading to MGDG synthesis was strongly affected by drought stress while the eukaryotic pathway was not. It was also observed that the molecular species of leaf PC became more saturated in drought stressed plants. This could be due to a specific decrease in oleate desaturase activity.

Journal Article↗