Low Glucosinolate Content Research Articles

Genome-wide characterization, expression analyses, and functional prediction of the NPF family in Brassica napus

BackgroundNITRATE TRANSPORTER 1/PEPTIDE TRANSPORTER (NRT1/PTR) family (NPF) members are essential transporters for many substrates in plants, including nitrate, hormones, peptides, and secondary metabolites. Here, we report the global characterization of NPF in the important oil crop Brassica napus, including that for phylogeny, gene/protein structures, duplications, and expression patterns.ResultsA total of 199 B. napus (BnaNPFs) NPF-coding genes were identified. Phylogenetic analyses categorized these genes into 11 subfamilies, including three new ones. Sequence feature analysis revealed that members of each subfamily contain conserved gene and protein structures. Many hormone−/abiotic stress-responsive cis-acting elements and transcription factor binding sites were identified in BnaNPF promoter regions. Chromosome distribution analysis indicated that BnaNPFs within a subfamily tend to cluster on one chromosome. Syntenic relationship analysis showed that allotetraploid creation by its ancestors (Brassica rapa and Brassica oleracea) (57.89%) and small-scale duplication events (39.85%) contributed to rapid BnaNPF expansion in B. napus. A genome-wide spatiotemporal expression survey showed that NPF genes of each Arabidopsis and B. napus subfamily have preferential expression patterns across developmental stages, most of them are expressed in a few organs. RNA-seq analysis showed that many BnaNPFs (32.66%) have wide exogenous hormone-inductive profiles, suggesting important hormone-mediated patterns in diverse bioprocesses. Homologs in a clade or branch within a given subfamily have conserved organ/spatiotemporal and hormone-inductive profiles, indicating functional conservation during evolution. qRT-PCR-based comparative expression analysis of the 12 BnaNPFs in the NPF2–1 subfamily between high- and low-glucosinolate (GLS) content B. napus varieties revealed that homologs of AtNPF2.9 (BnaNPF2.12, BnaNPF2.13, and BnaNPF2.14), AtNPF2.10 (BnaNPF2.19 and BnaNPF2.20), and AtNPF2.11 (BnaNPF2.26 and BnaNPF2.28) might be involved in GLS transport. qRT-PCR further confirmed the hormone-responsive expression profiles of these putative GLS transporter genes.ConclusionWe identified 199 B. napus BnaNPFs; these were divided into 11 subfamilies. Allopolyploidy and small-scale duplication events contributed to the immense expansion of BnaNPFs in B. napus. The BnaNPFs had preferential expression patterns in different tissues/organs and wide hormone-induced expression profiles. Four BnaNPFs in the NPF2–1 subfamily may be involved in GLS transport. Our results provide an abundant gene resource for further functional analysis of BnaNPFs.

The Eruca sativa Genome and Transcriptome: A Targeted Analysis of Sulfur Metabolism and Glucosinolate Biosynthesis Pre and Postharvest.

Rocket (Eruca sativa) is a source of health-related metabolites called glucosinolates (GSLs) and isothiocyanates (ITCs) but little is known of the genetic and transcriptomic mechanisms responsible for regulating pre and postharvest accumulations. We present the first de novo reference genome assembly and annotation, with ontogenic and postharvest transcriptome data relating to sulfur assimilation, transport, and utilization. Diverse gene expression patterns related to sulfur metabolism, GSL biosynthesis, and glutathione biosynthesis are present between inbred lines of rocket. A clear pattern of differential expression determines GSL abundance and the formation of hydrolysis products. One breeding line sustained GSL accumulation and hydrolysis product formation throughout storage. Multiple copies of MYB28, SLIM1, SDI1, and ESM1 have increased and differential expression postharvest, and are associated with GSLs and hydrolysis product formation. Two glucosinolate transporter gene (GTR2) copies were found to be associated with increased GSL accumulations in leaves. Monosaccharides (which are essential for primary metabolism and GSL biosynthesis, and contribute to the taste of rocket) were also quantified in leaves, with glucose concentrations significantly correlated with the expression of numerous GSL-related genes. Significant negative correlations were observed between the expression of glutathione synthetase (GSH) genes and those involved in GSL metabolism. Breeding line “B” showed increased GSH gene expression and low GSL content compared to two other lines where the opposite was observed. Co-expression analysis revealed senescence (SEN1) and oxidative stress-related (OXS3) genes have higher expression in line B, suggesting that postharvest deterioration is associated with low GSL concentrations.

Marker assisted selection of new high oleic and low linolenic winter oilseed rape (Brassica napus L.) inbred lines revealing good agricultural value.

Development of oilseed rape (Brassica napus L.) breeding lines producing oil characterized by high oleic and low linolenic acid content is an important goal of rapeseed breeding programs worldwide. Such kind of oil is ideal for deep frying and can also be used as a raw material for biodiesel production. By performing chemical mutagenesis using ethyl methanesulfonate, we obtained mutant winter rapeseed breeding lines that can produce oil with a high content of oleic acid (C18:1, more than 75%) and a low content of linolenic acid (C18:3, less than 3%). However, the mutant lines revealed low agricultural value as they were characterized by low seed yield, low wintering, and high content of glucosinolates in seed meal. The aim of this work was to improve the mutant lines and develop high-oleic and low-linolenic recombinants exhibiting both good oil quality and high agronomic value. The plant materials used in this study included high-oleic and low-linolenic mutant breeding lines and high-yielding domestic canola-type breeding lines of good agricultural value with high oleic acid content and extremely low glucosinolates content. Field trials were conducted in four environments, in a randomized complete block design. Phenotyping was performed for wintering, yield of seed and oil, and seed quality traits. Genotype × environment interaction was investigated with respect to the content of C18:1 and C18:3 acids in seed oil. Genotyping was done for the selection of homozygous high oleic and low linolenic lines using allele-specific CAPS markers and SNaPshot assay, respectively. Finally, new high oleic and low linolenic winter rapeseed recombinant lines were obtained for use as a starting material for the development of new varieties that may be of high value on the oil crop market.

Non-traditional feed and probiotics for rearing of goslings

Currently, considerable interest is caused by the study of the effect of various feed additives on the productive performance of animals. The ban on the use of antibiotics to stimulate poultry growth in many European countries has increased the interest of researchers and practitioners in the use of probiotics. It is important to study the use of non-traditional feed in animal husbandry. Thus, waste processing of rapeseed (presscake, meal) is the most important sources of essential amino acids (lysine, methionine, tryptophan, etc.), essential fatty acids (linoleic, linolenic, arachidonic, oleic, etc.). The importance of rapeseed seeds and products of its processing has increased after the breeding of varieties with a low content of erucic acid and glucosinolates. The purpose of the research was to study the use of non-traditional feed and probiotics in the rearing of goslings to obtain full-fl edged products when they are grown up to 4 months of age. The possibility of replacing sunflower presscake with rapeseed presscake of Siberian selection and partial replacement of full-fat soy with rapeseed oil has been carried out. It has been found that the treatment of goslings after birth with probiotics “Prolam” and “Monosporin” and their use in feeding the goslings had a positive effect on their growth and development. With an increase in production costs and an increase in the cost of feed, the prime cost of 1 kg of live weight gain has decreased when processing and feeding probiotic “Prolam” by 17,9 %, “Monosporin” by 15,4 %. It has been obtained profits on 1 head more from the use of probiotics by 29,8 and 35 Rubles, respectively, in comparison with the control group. The level of profitability when using probiotics in the 1st experimental group has increased by 29,7 %, in the 2nd group by 24,7 %. The weight of the semi-eviscerated carcass was higher in the experimental groups receiving rapeseed presscake and rapeseed presscake in combination with rapeseed oil, and exceeded the weight of the carcasses of the control group by 286,13 and 388,48 g, respectively. The mass of eviscerated carcasses was also higher in the experimental groups.

Canola-quality white mustard: Agronomic management and seed yield

Modern white mustard (Sinapis alba L.) cultivars have high concentrations of erucic acid and glucosinolates. The progress in the breeding and cultivation of oilseed crops has contributed to the development of canola-quality white mustard, a variety without erucic acid and with low glucosinolate content, which was released for commercial production in 2012. The introduction of a new variety of white mustard could require partial or complete modification of the relevant production technology. The agricultural requirements of new crop cultivars can be rapidly assessed in experiments with fractional factorial design. In 2016–2018, a field experiment with mixed 2m3k−1 factorial design, where five factors were tested at two and three levels, was carried out in the Agricultural Experiment Station in Bałcyny in north-eastern Poland. Two white mustard cultivars, including the traditional cultivar Radena and the canola-quality cultivar Warta, were sown on three dates: the optimal date (4–10 April), as well as 7 and 14 days past the optimal date. White mustard cultivars were grown at three levels of agricultural inputs (0, 1, 2) with different rates of nitrogen (80, 120 and 160 kg ha-1), sulfur (0, 20 and 40 kg ha-1) and boron fertilizers (0, 150 and 300 g ha-1). The yields of the traditional cultivar exceeded those of the canola-quality cultivar by 0.53 Mg ha-1 on average. Both cultivars produced the highest yields when sown on the optimal date. Delayed sowing (by 7 and 14 days) contributed to the greatest decrease in yield (32 % and 42 %, respectively) in a dry year (2018). The traditional cultivar was more sensitive to delayed sowing than the canola-quality cultivar. In both analyzed cultivars, nitrogen fertilizer delivered yield-forming effects up to the rate of 80 kg ha-1 (in the dry year) or 120 kg ha-1 (in the year with above-average precipitation, 2016–2017). In both cultivars, a significant increase in seed yield was observed in response to 20 kg S ha-1. Foliar application of boron fertilizer did not increase white mustard yields.

Analysis of spring rapeseed varieties (Brassica napus L. var. oleifera) presented in the State Register of Plant Varieties of Ukraine

Purpose. Determine the main indicators of productivity and quality of seeds of spring rapeseed new varieties during their cultivation in different argoclimatic zones of Ukraine. Methods. Field, laboratory. Field studies were carried out on the basis of the Branches of the Ukrainian Institute for Plant Variety Examination in the zones of Polissia, Forest-Steppe and Steppe in 2015–2016. Results. The State Regis­ter of Plant Varieties Suitable for Distribution in Ukraine (the Register of Plant Varieties of Ukraine) as at 22 August 2019 contains 60 varieties of spring rapeseed, of which 42 (70.0%) are of foreign origin and 18 (30.0%) are Ukrainian cultivars. The maximum sown area in Ukraine occupied by spring rapeseed was about 68.3 thousand ha in 2018, which is twice as much as the area of 2013. In 2019, a dramatic decrease in sown area was observed. The productivity of the studied rapeseed varieties in 2015–2016 in the Steppe zone was on average 0.94–1.17 t/ha; Forest-steppe – 2.16–2.29; Polissia – 1.33–1.62. The yields of individual varieties exceeded 2.0 t/ha; they had a high content of oil and crude protein and a low content of erucic acid and glucosinolates in the seeds. The content of erucic acid did not exceed 0.1%, glucosinolates – 0.8%. Conclusions. The highest yield in the zones of Forest-Steppe and Polissia was observed from ‘DK 7160 KL’ variety – 2.28 t/ha and 1.62 t/ha, respectively. The maximum crude protein content in the steppe zone was found in ‘Aksana’ variety (26.6%), in the Forest-steppe zone – in ‘Bilder’ (25.4%,) in the Polissia zone – in ‘Sander’ (24.9%). High oil content in seeds in the Steppe zone was in varieties ‘Bilder’ (45.0%) and ‘DK 7155 KL’ (45.2%), in the Forest-Steppe – in ‘Sander’ (46.5%) and ‘DK 7155 KL’ (46.6%); in Polissia – in ‘DK 7160 KL’ (47.1%) and ‘DK 7155 KL’ (46.8%). The minimum content of erucic acid in the seeds of spring rapeseed in the Steppe was in the varieties ‘Aksana’ and ‘DK 7150 KL’, in the Forest-Steppe – ‘GK 7160 KL’, ‘CLICK KL’, ‘DK 7155 KL’ and in the Polissia zone – ‘DK 7160 KL’ and ‘DK 7150 KL’.

PSVI-9 Nutrient and energy digestibility of steam-exploded canola meal in cannulated grower pigs

Abstract Nutrient digestibility is lower in canola meal (CM) than soybean meal due to its fiber matrix. High steam pressure processing may increase nutrient digestibility of CM in pigs. To explore, Brassica napus CM was processed at 700 or 1,100 kPa followed by sudden release of pressure to ambient and yielded steam-exploded CM7 and CM11, respectively. The CM, CM7, and CM11 were included at 40% in 3 test diets. An N-free diet was fed to pigs to measure basal endogenous losses of crude protein (CP) and amino acids (AA) and served as basal to measure energy digestibility of CM. Seven ileal cannulated grower pigs (initial BW, 29 kg) were fed the 4 diets over three 9-d periods in 2 Youden squares. Pigs were fed diets at 3.0 × maintenance (110 kcal of DE per kg of BW0.75). Compared to CM, CM7, and CM11 had reduced chemical availability of lysine (87.6 vs. 83.1 and 85.7%), but lower glucosinolate content (1.14 vs. 0.99 and 0.92 µmol/g). Apparent ileal and total tract digestibility of energy was lower (P < 0.05) for CM7 than CM and intermediate for CM11, resulting in lower (P < 0.05) predicted net energy for CM7 and CM11 than CM (1.88 and 1.91 vs. 1.94 Mcal/kg, respectively). Standardized ileal digestibility (SID) of lysine was lower (P < 0.05) for CM7 and CM11 than CM (67.1 and 70.3% vs. 74.3, respectively). The SID of threonine was lower (P < 0.05) for CM7 than CM and intermediate for CM11. In summary, steam-explosion of CM damaged lysine reducing its digestibility and did not increase energy digestibility. In conclusion, steam-explosion of CM did not increase nutrient digestibility of CM for pigs.

Plant glucosinolate content increases susceptibility to diamondback moth (Lepidoptera: Plutellidae) regardless of its diet

Glucosinolates are plant defense compounds used in host-plant recognition by insects specialized on Brassicaceae, such as the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae). We tested whether there were differences in oviposition and larval survival among three strains of P. xylostella after more than 100 generations continuously reared on cabbage leaves, pea leaves, and wheat germ-casein artificial diet. Pea leaves and wheat germ-casein diet contain no glucosinolates. Tests were conducted with a total of 30 different plant species, and their glucosinolate contents were determined. Two-choice oviposition tests (comparing each plant species to Arabidopsis thaliana L.) and no-choice oviposition tests showed that, regardless of diet, total glucosinolate content and chemical complexity index for glucosinolates were positively correlated with oviposition preference, total oviposition, and larval survival in P. xylostella across the wide range of plants tested. Our research shows that long-term feeding on glucosinolate-free diet hardly affects oviposition preference and larval survival in P. xylostella. Our study also suggests that, even when comparing different plant species, glucosinolate content is likely to be associated with host-plant preference and host-plant suitability in P. xylostella. This indicates that crop varieties with high glucosinolate content are likely to be more susceptible to damage by P. xylostella than crop varieties with lower glucosinolate content. Additional implications of these findings for management of this important pest are discussed. This is the first time that a study includes oviposition preference, total oviposition, larval survival, and glucosinolate content across such a wide range of plant species.

Breeding of spring turnip rape in the Western Siberia

The territory of the Western Siberia is very suitable for cultivation of cruciferous oil crops (rapeseed and turnip rape) by its biological-climatic potential and soil conditions. Oil crops are widely used for human nutrition, feeding of animals, in any industries and building industry, medicine and perfumery. These crops oil contains many unsaturated fatty acids (oleic, linoleic, linolenic) which are essential in human nutrition. The main task of turnip rape breeding is productivity increase; much attention is paid to oil increase in seeds and improvements of oil quality (low content of glucosinolates in seeds and erucic acid absence in oil). We presented brief characteristics of released turnip rape varieties: productivity (seed yield, oil content and oil yield) and fatty acid composition of oil. The created varieties are differed with their high adaptability to severe Siberian conditions and resistance to the main bio- and abiofactors of environments.

Development of a Fertility Restorer for inap CMS (Isatis indigotica) Brassica napus Through Genetic Introgression of One Alien Addition.

Novel Brassica napus cytoplasmic male sterility (CMS) with carpelloid stamens (inap CMS) was produced by intertribal somatic hybridization with Isatis indigotica (Chinese woad), but its RF (restorer of fertility) gene(s) existed in one particular woad chromosome that was carried by one fertile monosomic alien addition line (MAAL) of rapeseed. Herein, the selfed progenies of this MAAL were extensively selected and analyzed to screen the rapeseed-type plants (2n = 38) with good male fertility and to produce their doubled haploid (DH) lines by microspore culture. From the investigation of fertility restoration in the F1 hybrids with inap CMS, one DH line (RF 39) was identified to adequately restore male fertility and likely carried one dominant RF gene. Specifically, this restorer produced brown pollen grains, similar to the woad and the MAAL, suggesting that this trait is closely linked with the RF gene(s) and serves as one phenotypic marker for the restorer. This restorer contained 38 chromosomes of rapeseed and no intact chromosomes of woad, but some DNA fragments of woad origin were detected at low frequency. This restorer was much improved for pollen and seed fertility and for low glucosinolate content. The successful breeding of the restorer for inap CMS rendered this new pollination control system feasible for rapeseed hybrid production.

A naturally occurring variation in the BrMAM-3 gene is associated with aliphatic glucosinolate accumulation in Brassica rapa leaves

Glucosinolate profiles significantly vary among Brassica rapa genotypes. However, the molecular basis of these variations is largely unknown. In this study, we investigated a major quantitative trait locus (QTL) controlling aliphatic glucosinolate accumulation in B. rapa leaves. The QTL, which encompasses three tandem MAM genes and two MYB genes, was detected in two BC2DH populations. Among the five-candidate genes, only the expression level of BrMAM-3 (Bra013007) was significantly correlated with the accumulation of aliphatic glucosinolates in B. rapa leaves. We identified a naturally occurring insertion within exon 1 of BrMAM-3, which is predicted to be a loss-of-function mutation, as confirmed by qRT-PCR. We determined that the loss of function was associated with the low glucosinolate content in B. rapa accessions. Furthermore, overexpressing the BrMAM-3 gene resulted in an increase in total aliphatic glucosinolates in Arabidopsis transgenic lines. Our study provides insights into the molecular mechanism underlying the accumulation of aliphatic glucosinolates in B. rapa leaves, thereby facilitating in the manipulation of total aliphatic glucosinolate content in Brassica crops.

Heat-treated rapeseed expeller press cake with extremely low glucosinolate content reduce transfer of iodine to cow milk

The main objective of this study was to investigate the effect of increasing dietary levels of heat treated low glucosinolate rapeseed expeller press cake (RSC) on the transfer of iodine from feed to cow milk. Eight cows of the Norwegian red cattle breed were split in two 4 × 4 Latin squares, using 4 treatments and 4 periods of 14 days each. The 4 different treatments were 1) Control, 0.0 kg RSC/day, 2) RSC-Low, 0.6 kg RSC/day, 3) RSC-Medium, 1.4 kg RSC/day and 4) RSC-High, 2.0 kg RSC/day. Irrespective of a planned constant dietary iodine content, the analysed concentration of iodine ranged from 1.4 mg/kg DM in the RSC-High diet to 1.9 mg/kg DM in the Control diet. From day 11–14 in each period, samples were collected and the total iodine concentrations in feed, milk and plasma were determined by inductively coupled plasma mass spectrometry. The iodohormones, triiodothyronine (T3) and thyroxin (T4) in plasma were determined by fluoroimmunoassay. No differences (P > 0.05) in total iodine as well as the T3 and T4 plasma concentrations were observed between the four treatments, even though the plasma iodine reflected the somewhat varying dietary iodine. Feed intake, milk production and milk composition was not affected by the different treatments (P > 0.05). Although the levels of glucosinolates were low and no glucosinolate metabolites (e.g., goitrin and indole acetonitrile) were found in the RSC, an increasing offer decreased the milk iodine concentration from 0.35 mg/kg in the Control to 0.25 mg/kg with RSC-Low, to 0.15 mg/kg with RSC-Medium and to 0.10 mg/kg with RSC-High treatments. The iodine transfer, i.e. the output of iodine via milk related to the iodine intake, amounted to 25, 19, 13 and 10% in the Control and the 3 groups with increasing dietary RSC level. This study indicates that milk iodine transfer is severely inhibited at considerably lower levels of glucosinolates in RSC than previously anticipated.

Rezultati ispitivanja proizvodne i upotrebne vrednosti hibrida uljane repice tolerantnih na herbicide iz grupe imidazolinona

In rapeseed production weeds represent one of the limiting factors for achieving high yields. Imidazolinones control wide range of weeds and are applied after the emergence of crops and weeds. Clearfield® technology is based on the existence of a resistance gene against herbicides of imidazolinone (IMI) group in cultivated plants. All rapeseed hybrids whose resistance is based on the resistance gene from PM1 and PM2 are called Clearfield® rapeseed. In this paper content of oil, erucic acid and glucosinolates were analysed during three vegetation seasons. Hybrid tolerance for recommended and double increased amounts of imazamox and metazachlor based herbicide was also graded. Average yield of tested Clearfield® hybrids was less than average yield of standard rapeseed hybrids. Investigated hybrids had low glucosinolate content, and the erucic acid content was far below the allowed 2%. Phytotoxicity was manifested in the form of leaf chlorosis on small number of genotypes. Given the smaller yields of Clearfield® rapeseed hybrids in comparison to standard hybrids, IMI hybrid sowing is recommended only on fields having dominant weeds, which can be more efficient suppressed by herbicides based on imazamox.

Glucosinolate Content of Camelina Genotypes as Affected by Applied Nitrogen and Sulphur

Camelina [Camelina sativa (L.) Crantz] is an alternative oil crop that has potential in aquaculture and food production. However, glucosinolates (GSs) in camelina seed and meal constrain their application in human and animal consumption. Glucosinolates are plant secondary metabolites commonly found in the Brassicaceae family. The aims of this study were to determine whether nitrogen (N) alone or in combination with sulphur (S) application affected GS concentration in camelina seeds, as well as whether different genotypes differed in GS concentrations. Our results showed that the application of 25 kg S ha−1 significantly increased GS content compared with 0 kg S ha−1. Applied N rates were negatively correlated with the amounts of total and individual GSs when no S was applied. The low GS content with high N rates was probably due to a dilution effect of S content. Applied N rates did not affect the amounts of total and individual GSs when 25 kg S ha−1 was applied. Seed protein content was negatively correlated with the total GSs depending on growing season and genotype when no S was applied. The cultivar, Calena, had the highest amount of GSs among five genotypes. The results indicated that GSs in camelina can be manipulated by cultural management practices including N and S application.

Comparative analysis of MYB28 homologs and development of a MYB28-specific marker in Brassica napus L.

Glucosinolates are a major class of secondary metabolites in Brassicaceae species, whose degradation products are proving to be increasingly important for human health and in crop protection. MYB28 is important for regulating glucosinolate biosynthesis in Arabidopsis thaliana. Brassica napus L. is one of the closest relatives of A. thaliana, and in theory, contains several MYB28 homologs in its genome. Only a few transcriptional regulators of aliphatic glucosinolate biosynthesis genes in Brassica crops have been functionally characterized. Therefore, the aims of this study were to clarify the distribution of MYB28 homologs in the B. napus genome, and to determine the gene expression status and function of these homologs, which may have important implications for plant breeding. Based on the A. thaliana MYB28 sequence, six BnMYB28 homologs were identified and mapped to six linkage groups of a doubled haploid population. Gene expression analyses revealed that the homologs exhibited different expression patterns in different tissues. Additionally, the function of BnA9.MYB28 was confirmed by generating BnA9.MYB28-overexpressing transgenic plants and completing association mapping analyses. One insertion/deletion marker was detected in cultivars with high or low glucosinolate contents. Our results highlight the importance of MYB28 homologs for regulating complex glucosinolate traits in the polyploid crop B. napus. The gene and marker information generated in this study may be useful for marker-assisted breeding of oilseed rape.

Validation of molecular markers linked to low glucosinolate QTLs for marker assisted selection in Indian mustard (Brassica junceaL. Czern & Coss)

Six earlier reported markers closely linked to low glucosinolate QTLs of Brassica juncea, spread across ‘A’ genome (A2, A3 and A9) were validated in a recombinant inbred line (RIL) population of a cross between Pusa Mustard-21 (low erucic acid) and EC-597325 (double low) genotypes, to utilize them in marker-assisted selection (MAS). Of them, four markers viz., GER 1 amplified alleles of 650 bp and of 950 bp, GER 5 amplified 310 bp and 350 bp, At5gAJ67 amplified 500 bp and 450 bp and Myb28 amplified alleles of size 900 bp and 920 bp in EC597325 and Pusa Mustard-21, respectively and therefore differentiated low and high glucosinolate parents. These four polymorphic markers were then used to genotype the phenotyped RIL population consisting 608 plants. Marker-trait association was tested for goodness of fit using 2 test. Of the four markers, GER1 and GER5 showed higher phenotypic variance (R2 value) compared to the others, indicating their significance in determination of glucosinolates and prospects for use in MAS for development of Indian mustard genotypes with low glucosinolates content.

Regulated expression of a cytokinin biosynthesis gene IPT delays leaf senescence and improves yield under rainfed and irrigated conditions in canola (Brassica napus L.).

Delay of leaf senescence through genetic modification can potentially improve crop yield, through maintenance of photosynthetically active leaves for a longer period. Plant growth hormones such as cytokinin regulate and delay leaf senescence. Here, the structural gene (IPT) encoding the cytokinin biosynthetic enzyme isopentenyltransferase was fused to a functionally active fragment of the AtMYB32 promoter and was transformed into canola plants. Expression of the AtMYB32xs::IPT gene cassette delayed the leaf senescence in transgenic plants grown under controlled environment conditions and field experiments conducted for a single season at two geographic locations. The transgenic canola plants retained higher chlorophyll levels for an extended period and produced significantly higher seed yield with similar growth and phenology compared to wild type and null control plants under rainfed and irrigated treatments. The yield increase in transgenic plants was in the range of 16% to 23% and 7% to 16% under rainfed and irrigated conditions, respectively, compared to control plants. Most of the seed quality parameters in transgenic plants were similar, and with elevated oleic acid content in all transgenic lines and higher oil content and lower glucosinolate content in one specific transgenic line as compared to control plants. The results suggest that by delaying leaf senescence using the AtMYB32xs::IPT technology, productivity in crop plants can be improved under water stress and well-watered conditions.

Broadening genetic diversity inBrassica napuscanola: Development of canola-quality springB. napusfromB. napus×B. oleraceavar.alboglabrainterspecific crosses

Rahman, H., Bennett, R. A. and Séguin-Swartz, G. 2015. Broadening genetic diversity in Brassica napus canola: Development of canola-quality spring B. napus from B. napus × B. oleracea var. alboglabra interspecific crosses. Can. J. Plant Sci. 95: 29–41. The narrow genetic base in spring Brassica napus (AACC) canola is a limitation for continued improvement of this crop. This research focused on broadening of genetic diversity in spring canola by using B. oleracea (CC). Seeds of B. oleracea contain high levels of erucic acid and glucosinolates, which are undesired in canola. Therefore, inheritance of these traits and the prospect of developing spring canola with allelic diversity introgressed from B. oleracea were investigated in B. napus×B. oleracea interspecific progenies. Zero-erucic plants in F2generation occurred at a lower frequency than expected based on segregation involving only the C-genome erucic acid alleles. Selection in F2to F3focused on zero erucic acid, while focus in later generation was for low glucosinolate and B. napus plants. In the F6, 31% zero-erucic families had low glucosinolate content. Flow cytometry analysis of the F8families showed no significant difference from the B. napus parent. Genetic diversity analysis by using simple sequence repeat markers from the C-genome chromosomes showed that the F8families received up to 54% alleles from B. oleracea. The results demonstrate the feasibility of enriching genetic diversity in B. napus canola by using B. oleracea.

Detection and molecular characterization of two FAD3 genes controlling linolenic acid content and development of allele-specific markers in yellow mustard (Sinapis alba).

Development of yellow mustard (Sinapis alba L.) with superior quality traits (low erucic and linolenic acid contents, and low glucosinolate content) can make this species as a potential oilseed crop. We have recently isolated three inbred lines Y1127, Y514 and Y1035 with low (3.8%), medium (12.3%) and high (20.8%) linolenic acid (C18∶3) content, respectively, in this species. Inheritance studies detected two fatty acid desaturase 3 (FAD3) gene loci controlling the variation of C18∶3 content. QTL mapping revealed that the two FAD3 gene loci responsible for 73.0% and 23.4% of the total variation and were located on the linkage groups Sal02 and Sal10, respectively. The FAD3 gene on Sal02 was referred to as SalFAD3.LA1 and that on Sal10 as SalFAD3.LA2. The dominant and recessive alleles were designated as LA1 and la1 for SalFAD3.LA1, and LA2 and la2 for SalFAD3.LA2. Cloning and alignment of the coding and genomic DNA sequences revealed that the SalFAD3.LA1 and SalFAD3.LA2 genes each contained 8 exons and 7 introns. LA1 had a coding DNA sequence (CDS) of 1143 bp encoding a polypeptide of 380 amino acids, whereas la1 was a loss-of-function allele due to an insertion of 584 bp in exon 3. Both LA2 and la2 had a CDS of 1152 bp encoding a polypeptide of 383 amino acids. Allele-specific markers for LA1, la1, LA2 and la2 co-segregated with the C18∶3 content in the F2 populations and will be useful for improving fatty acid composition through marker assisted selection in yellow mustard breeding.

Factors affecting morphogenetic potential in oilseed rape roots of the Skrzeszowicki and Start cultivars

The effect of the origin of root segments, seedling age, growth substances and gelled or liquid media were tested in respect to the morphogenetic potential of rape root segments of Skrzeszowicki (high glucosinolate content) and Start (low glucosinolate content) cultivars. Callus and roots were formed on all root segments after an approximately 2 week growth period; buds were formed after ca. 4 weeks only on segments adjacent to the hypocotyl. Higher concentrations of auxin and cytokinins were required for bud induction. Cultivar differences in the morphogenetic responses of the root segments were found. They were manifested by the more abundant callus formation (BAP+NAA) and more numerous lateral roots and buds (KIN+IBA) on segments from the Skrzeszowicki cultivar than from the Start cultivar.