Seed Glucosinolate Content Research Articles

Remobilization and fate of sulphur in mustard.

Background and AimsSulphur (S) is an essential macronutrient involved in numerous metabolic pathways required for plant growth. Crops of the plant family Brassicaceae require more S compared with other crops for optimum growth and yield, with most S ultimately sequestered in the mature seeds as the storage proteins cruciferin and napin, along with the unique S-rich secondary metabolite glucosinolate (GSL). It is well established that S assimilation primarily takes place in the shoots rather than roots, and that sulphate is the major form in which S is transported and stored in plants. We carried out a developmental S audit to establish the net fluxes of S in two lines of Brassica juncea mustard where seed GSL content differed but resulted in no yield penalty.MethodsWe quantified S pools (sulphate, GSL and total S) in different organs at multiple growth stages until maturity, which also allowed us to test the hypothesis that leaf S, accumulated as a primary S sink, becomes remobilized as a secondary source to meet the requirements of GSL as the dominant seed S sink.Key ResultsMaximum plant sulphate accumulation had occurred by floral initiation in both lines, at which time most of the sulphate was found in the leaves, confirming its role as the primary S sink. Up to 52 % of total sulphate accumulated by the low-GSL plants was lost through senesced leaves. In contrast, S from senescing leaves of the high-GSL line was remobilized to other tissues, with GSL accumulating in the seed from commencement of silique filling until maturity.ConclusionWe have established that leaf S compounds that accumulated as primary S sinks at early developmental stages in condiment type B. juncea become remobilized as a secondary S source to meet the demand for GSL as the dominant seed S sink at maturity.

Genome-wide identification of loci affecting seed glucosinolate contents in Brassica napus L.

Glucosinolates are amino acid-derived secondary metabolites that act as chemical defense agents against pests. However, the presence of high levels of glucosinolates severely diminishes the nutritional value of seed meals made from rapeseed (Brassica napus L.). To identify the loci affecting seed glucosinolate content (SGC), we conducted genome-wide resequencing in a population of 307 diverse B. napus accessions from the three B. napus ecotype groups, namely, spring, winter, and semi-winter. These resequencing data were used for a genome-wide association study (GWAS) to identify the loci affecting SGC. In the three ecotype groups, four common and four ecotype-specific haplotype blocks (HBs) were significantly associated with SGC. To identify candidate genes controlling SGC, transcriptome analysis was carried out in 36 accessions showing extreme SGC values. Analyses of haplotypes, genomic variation, and candidate gene expression pointed to five and three candidate genes in the common and spring group-specific HBs, respectively. Our expression analyses demonstrated that additive effects of the three candidate genes in the spring group-specific HB play important roles in the SGC of B. napus.

QTL Mapping of Seed Glucosinolate Content Responsible for Environment in Brassica napus.

Glucosinolates (GSLs) are a major class of secondary metabolites. The content of seed GSL is largely regulated by environments in rapeseed (Brassica napus). However, the genetic control of seed GSL content responsible for environment in B. napus has been poorly understood. In the current study, a doubled haploid (DH) population from a cross between winter and semi-winter lines of rapeseed was grown in two distinct eco-environments, Germany and China, to evaluate the eco-environment effect and dissect the quantitative trait loci (QTL) responsible for environment for seed GSL in rapeseed. The deviation value of GSL content between eco-environments (GSLE) was calculated for each line in the DH population and the QTLs for GSLE were detected. GSLE ranged from −46.90 to 36.13 μmol g−1 meal in the DH population, suggesting the prominent eco-environmental effects for seed GSL in rapeseed. Four QTLs for GSLE were identified on chromosomes A04, A06, and A09 explaining 4.70∼9.93% of the phenotypic variation. Comparison of QTLs of seed GSL content between different eco-environments found three QTLs for GSL on A02 from 37.6 to 45.4 cM, A04 from 0 to 17.2 cM, and A09 from 67.0 to 98.6 cM exhibited significant difference of QTL effect between the German and Chinese eco-environments (P < 0.01), indicating the environment sensibility of these loci on seed GSL content. Moreover, flowering time (FT), an important environment adaptation trait in plant, was also investigated in this study. Comparative QTL analysis among GSLE, GSL, and FT revealed that three regions on chromosomes A02, A04, and A09 not only exhibited significant differences in QTL effect between Germany and China, but also co-located with the QTL intervals of GSLE and FT. Our results revealed that most of the GSL loci can influence GSL accumulation under different eco-environments, whereas the three QTL intervals on A02, A04, and A09 might be sensitive to the eco-environments for seed GSL content.

Jasmonic Acid-Mediated Aliphatic Glucosinolate Metabolism Is Involved in Clubroot Disease Development in Brassica napus L.

Glucosinolate (GSL) is associated with clubroot disease, which is caused by the obligate biotrophic protist Plasmodiophora brassicae. Due to the complicated composition of GSLs, their exact role in clubroot disease development remains unclear. By investigating clubroot disease resistance in cruciferous plants and characterizing the GSL content in seeds, we can determine if clubroot disease development is related to the components of GSLs. The difference in the infection process between Matthiola incana L. (resistant) and Brassica napus L. (susceptible) was determined. Root hair infection was definitely observed in both resistant and susceptible hosts, but no infection was observed during the cortical infection stage in resistant roots; this finding was verified by molecular detection of P. brassicae via PCR amplification at various times after inoculation. Based on the time course detection of the contents and compositions of GSLs after P. brassicae inoculation, susceptible roots exhibited increased accumulation of aliphatic, indolic, and aromatic GSLs in B. napus, but only aromatic GSLs were significantly increased in M. incana. Gluconapin, which was the main aliphatic GSL in B. napus and present only in B. napus, was significantly increased during the secondary infection stage. Quantification of the internal jasmonic acid (JA) concentration showed that both resistant and susceptible plants exhibited an enhanced level of JA, particularly in susceptible roots. The exogenous JA treatment induced aliphatic GSLs in B. napus and aromatic GSLs in M. incana. JA-induced aromatic GSLs may be involved in the defense against P. brassicae, whereas aliphatic GSLs induced by JA in B. napus likely play a role during the secondary infection stage. Three candidate MYB28 genes regulate the content of aliphatic GSLs identified in B. napus; one such gene was BnMYB28.1, which was significantly increased following both the treatment with exogenous JA and P. brassicae inoculation. In summary, the increased content of JA during the secondary infection stage may induce the expression of BnMYB28.1, which caused the accumulation of aliphatic GSLs in clubroot disease development.

Identification of Candidate Genes for Seed Glucosinolate Content of Rapeseed by Using Genome-wide Association Mapping and Co-expression Networks Analysis

Identification of Candidate Genes for Seed Glucosinolate Content of Rapeseed by Using Genome-wide Association Mapping and Co-expression Networks Analysis

Development of genic cleavage markers in association with seed glucosinolate content in canola.

The orthologues of Arabidopsis involved in seed glucosinolates metabolism within QTL confidence intervals were identified, and functional markers were developed to facilitate breeding for ultra-low glucosinolates in canola. Further reducing the content of seed glucosinolates will have a positive impact on the seed quality of canola (Brassica napus). In this study 43 quantitative trait loci (QTL) for seed glucosinolate (GSL) content in a low-GSL genetic background were mapped over seven environments in Germany and China in a doubled haploid population from a cross between two low-GSL oilseed rape parents with transgressive segregation. By anchoring these QTL to the reference genomes of B. rapa and B. oleracea, we identified 23 orthologues of Arabidopsis involved in GSL metabolism within the QTL confidence intervals. Sequence polymorphisms between the corresponding coding regions of the parental lines were used to develop cleaved amplified polymorphic site markers for two QTL-linked genes, ISOPROPYLMALATE DEHYDROGENASE1 and ADENOSINE 5'-PHOSPHOSULFATE REDUCTASE 3. The genic cleavage markers were mapped in the DH population into the corresponding intervals of QTL explaining 3.36-6.88 and 4.55-8.67 % of the phenotypic variation for seed GSL, respectively. The markers will facilitate breeding for ultra-low seed GSL content in canola.

Biochemical attributes of Indian mustard (Brassica juncea) and rapeseed (B. napus) as influenced by salicylic acid and benzothiadiazole

A field experiment was conducted during 2011-12 at Punjab Agricultural University, Ludhiana, India to assess the effect of foliar application of elicitors viz., salicylic acid (SA) and benzothiadiazole (BTH) on biochemical constituents of Brassica seeds. Seeds of Brassica juncea and B. napus were sown in the field during rabi season. Four different treatments of elicitors along with a fungicide and control were given to 10 week old plants up to four consecutive weeks. After harvesting, the seeds were analyzed for oil, total soluble protein and glucosinolate content. Results indicated that the elicitor treatments increased the oil, total soluble protein and glucosinolate content in seeds of both the Brassica species. In B. juncea, BTH (7 ppm) + SA (17 ppm) showed 12.5% higher oil content than control. In B. napus, the combinations of elicitors viz., BTH (3 ppm) + SA (33 ppm) and BTH (7 ppm) + SA (17 ppm) exhibited 15% increase in oil content compared to control. Treatment containing BTH (3 ppm) + SA (33 ppm) showed 18.72 and 15.86% higher total soluble protein content in B. juncea and B. napus seeds, respectively compared to control. In B. juncea, BTH (3 ppm) + SA (33 ppm) exhibited 7.13% higher glucosinolate content compared to control. In B. napus, BTH (7 ppm) + SA (17 ppm) showed 11.23% higher glucosinolate content than control. In conclusion, the application of elicitors, i.e., SA and BTH could be a useful tool for improving the nutritive value of B. juncea and B. napus seeds.

Genetic Study and QTL Mapping of Seed Glucosinolate Content in Brassica rapa L.

ABSTRACTSelf‐incompatibility in Brassica rapa L. is a major impediment to experimental studies on the genetic control of quantitative traits such as seed glucosinolate (GSL) content. In this paper, we report quantitative trait loci (QTL) mapping of total seed GSL content using a recombinant inbred line (RIL) population derived from two self‐compatible high‐ and low‐GSL B. rapa grown under different environmental conditions. Furthermore, quantitative genetic analysis using the parents and their F1, F2, B1 (F1 backcrossed to high‐parent P1), B2 (F1 backcrossed to low‐parent P2), and self‐pollinated progenies of B1 generation populations are also reported. Quantitative genetic analysis showed that additive genetic variance was consistently significant under different environments, while the dominance effect was significant under one growth condition. However, a simple additive‐dominance model was inadequate to explain the segregation variation among the generation means. Nonallelic interaction effects were important in the genetic control of GSL content in early generations where the levels of heterozygosity remained high. QTL mapping detected three loci at the linkage groups A2, A7, and A9 involved in the control of this trait. These QTL individually explained 5 to 22% of total phenotypic variation. The QTL on A9 was detected in all environments and explained 22%, the greatest amount of phenotypic variation. No additive × additive gene interaction was detected based on QTL analysis, and this also largely agreed with quantitative genetic analysis. Similarly, the number of loci detected based on QTL mapping also agree with the results obtained from quantitative genetic analysis.

Glucosinolates in the new oilseed crop meadowfoam: natural variation in Section Inflexae of Limnanthes, a new glucosinolate in L. floccosa, and QTL analysis in L. alba

With 5 figures and 4 tablesAbstractMeadowfoam, an oilseed crop grown in the Willamette Valley of Oregon, was developed from Limnanthes alba (Benth.), an herbaceous winter annual native to the west coast of North America. Meadowfoam oil is valued for unique properties attributed to the predominance of very long‐chain fatty acids and desaturation at the Δ5 position. Seed meal remaining after commercial oil extraction contains intact glucosinolates and has potential pesticidal properties owing to isothiocyanate and nitrile glucosinolate derivatives. We identified and quantitated seed glucosinolates in four species of Section Inflexae of Limnanthes to assess variation for this trait in primary and secondary gene pools of cultivated meadowfoam. Glucosinolate content in seeds ranged from 30 to 204 μmol/g dry weight. Only glucolimnanthin (3‐methoxybenzyl glucosinolate) was detected in L. alba, L. montana and L. gracilis, but L. floccosa contained glucolepigramin (3‐hydroxybenzyl glucosinolate) as well as glucolimnanthin. Two QTL affecting seed glucosinolate content were identified in an inter‐subspecific BC1 population derived from a cross between L. alba subsp. alba and L. alba subsp. versicolor.

Screening for erucic acid and glucosinolate content in rapeseed-mustard seeds using near infrared reflectance spectroscopy

Using partial least square regression, calibration for non-destructive estimation of erucic acid and glucosinolate contents in seeds of rapeseed-mustard by Fourier transform near infrared reflectance spectroscopy (FT-NIRS) was developed. The calibration developed showed a very close relationship between the reference method for erucic acid (gas chromatography) and glucosinolate content (palladium complex formation) and NIR spectral data from 7502.1 to 5444.6cm. (-1) The coefficients of determinations were 97.16% and 98.34% for erucic acid and glucosinolate contents, respectively.

Genotypic effects on the phytochemical quality of seeds and sprouts from commercial broccoli cultivars

Determining ontogenic diversity in vegetables, in general or Brassicas in particular, regarding the bioactive content, is an interesting task since the most promising Brassicaceae foods could have the highest nutritional and health-promoting properties. Therefore, vitamin C, phenolic compounds, glucosinolate content, and total antioxidant capacity were evaluated in commercial cultivars of broccoli ( Brassica oleracea var. italica; cv. Nubia, cv. Marathon and cv. Viola) seeds and during the sprouting period. Vitamin C was not detected in dormant seeds and its content increased with the germination, reaching values ranging from 53 (cv. Nubia) to 64 (cv. Marathon) mg/100 g FW, at the end of the monitored period (14days). The total glucosinolate content in seeds and 3-day-old sprouts was higher in cv. Marathon (1005 and 556 mg/100 g FW, respectively), however cv. Viola sprouts registered the highest glucosinolate content 7 and 14 days after sowing (235 and 208 mg/100 g FW, respectively). Aliphatic glucosinolates were more affected by genetic factors than the indolic glucosinolates, being glucoraphanin the predominant glucosinolate in cv. Nubia and cv. Marathon, whereas glucoiberin was the major glucosinolate in cv. Viola. The flavonoid and total phenolic content was significantly higher in cv. Viola. Also, seeds of this cultivar showed the highest antioxidant capacity (2.7 mg Trolox/g FW). This study confirmed that the potential value of edible broccoli sprouts for human health depends largely on the genotype.

Development of fertility restorers of winter oilseed rape with low glucosinolate content for the CMS Ogu-INRA system

We have bred low glucosinolate (GSL) winter oilseed rape lines carrying the fertility restorer for the CMS Ogu-INRA system. The original restorer line BO20 contained 31&amp;mu;mol/g GSL in seeds, but by crossing this line with various low GSL CMS lines, followed by repeated selection of fertile segregants, we were able to obtain fertile lines with a mean GSL content in seeds of 11.8 &amp;mu;mol/g. This result confirmed that the gene(s) controlling the GSL content are not closely linked to the fertility restorer gene. The results confirm, that the SCAR marker SG34 is closely associated with the fertility restoring allele, and facilitates so the selection of fertile segregants; however, the marker is unable to distinguish between the homozygous RfRf and the heterozygous Rfrf genotypes.

QTL analysis reveals context-dependent loci for seed glucosinolate trait in the oilseed Brassica juncea: importance of recurrent selection backcross scheme for the identification of ‘true’ QTL

Seed glucosinolate content in Brassica juncea is a complex quantitative trait. A recurrent selection backcross (RSB) method with a doubled haploid (DH) generation interspersing backcross generations was used for the introgression of low glucosinolate alleles from an east European gene pool B. juncea line, Heera into an Indian gene pool variety, Varuna. Phenotypic comparisons among the DH populations derived from early to advanced backcrosses revealed a shift in the mean values for various glucosinolates with the advancement of backcrossing, indicating a change in the selective values of the alleles with change in the genetic background due to the existence of epistasis and context dependencies. QTL mapping for various seed glucosinolates from early (F(1)DH) and advanced generation (BC(4)DH) populations confirmed the presence of epistasis and context dependency. The common QTL detected in both F(1)DH and BC(4)DH changed their R (2) values from the former to the later generation. Some of the QTL detected in the F(1)DH became irrelevant in the BC(4)DH population. Further, new QTL were detected in the BC(4)DH population for various glucosinolates. A validation study on a population of low glucosinolate DH lines derived from all the backcross generations of the RSB breeding programme revealed that the QTL detected in BC(4)DH were the 'true' QTL. Using glucosinolate as an example, the study provides strong evidence for the importance of the RSB method for the identification of the 'true' QTL which would be significant for marker assisted introgression of a complex quantitative trait whose expression is influenced by epistatic interactions.

Canola Seed Glucosinolate Content as Affected by Boron Availability Under Water Stress

It is hypothesized that soil boron (B) availability is influenced by water stress and affects canola glucosinolate content. This research was conducted to determine if added B can overcome water stress-induced changes in seed glucosinolate content in canola. The cultivars Cyclone and American A112 were grown in a continuously recirculating hydroponic system with modified Hoagland solutions. The experimental design was a randomized incomplete block. Two B concentrations and one water stress treatment (maintained with polyethylene glycol 8000, PEG) were used: 0.04 mg·L–1 B (not water stressed, without PEG), 0.04 mg·L–1 B (water stressed, with PEG), and 0.60 mg·L–1 B (water stressed, with PEG). Osmotic potential was maintained at –0.1 MPa (with PEG) or 0.05 MPa (without PEG). The 0.04-mg·L–1 B treatment without PEG had significantly lower total glucosinolates than the 0.04-mg·L–1 B treatment with PEG. This indicates that at low available B levels, glucosinolate content is increased by water stress. The 0.04-mg·L–1 B treatment with PEG had significantly higher total glucosinolates than the 0.60 -mg·L–1 B treatment with PEG. Thus, under water stress, the higher available B treatment resulted in lower seed glucosinolate content.

Glucosinolate Content in Seeds from Silique at Different Position ofBrassica campestris

Abstract The glucosinolate content in seeds of two new yellow sarson cultivars (Brassica campestris L.) has been investigated and its variation as a function of different positions of siliques on the plants has been determined. The total glucosinolate content was dominated by but-3-enylglucosinolate (ca. 90%). Significant silique position effects were found. Higher glucosinolate concentrations were found in seeds from siliques at the top of the branch than in those from the basal part of the branch. The highest glucosinolate concentration was found in seeds from top siliques of the lowest branch. The knowledge of the effect of silique position on glucosinolate content in the seeds in relation to oilseed rape plant breeding are discussed.