Dataset Information

Genome-Wide Mapping of Loci Associated With Resistance to Clubroot in Brassica napus ssp. napobrassica (Rutabaga) Accessions From Nordic Countries.

ABSTRACT: Rutabaga [Brassica napus ssp. napobrassica (L.) Hanelt] is reported to be an excellent source of clubroot (Plasmodiophora brassicae) resistance genes. In this study, 124 rutabaga accessions from the Nordic countries (Norway, Sweden, Finland, Denmark, and Iceland) were evaluated for their reaction to five single-spore isolates representing P. brassicae pathotypes 2F, 3H, 5I, 6M, and 8N and 12 field isolates representing pathotypes 2B, 3A, 3O, 5C, 5G, 5K, 5L, 5X (two isolates, L-G2 and L-G3), 8E, 8J, and 8P. The accessions were also genotyped using a 15K Brassica SNP array and 60 PCR-based primers linked to previously identified clubroot resistance genes. Six thousand eight hundred sixty-one SNP markers were retained after filtering with TASSEL 5.0, and used to evaluate four general linear models (GLM) and four mixed linear models (MLM). The PCA + K and Q + K MLM models gave the minimal deviance of the observed from the expected distribution in quantile-quantile plots, and hence were used for SNP-clubroot association analyses. In addition, 108 alleles derived from the PCR-based markers and the phenotypic data were analyzed with the PCA + K model. Forty-five SNPs and four PCR-based markers were identified to be associated strongly with resistance to isolates representing 13 pathotypes (2F, 3H, 5I, 6M, 8N, 2B, 3A, 3O, 5C, 5G, 5K, 5L, and 8P). These markers revealed the top and bottom segments of rutabaga chromosome A03 and the middle segment of chromosome A08 as genomic hotspots associated with resistance to the different P. brassicae pathotypes.

SUBMITTER: Fredua-Agyeman R

PROVIDER: S-EPMC7303339 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Genome-Wide Mapping of Loci Associated With Resistance to Clubroot in Brassica napus ssp. napobrassica (Rutabaga) Accessions From Nordic Countries.

Fredua-Agyeman Rudolph R Yu Zhiyu Z Hwang Sheau-Fang SF Strelkov Stephen E SE

Frontiers in plant science 20200612

Rutabaga [Brassica napus ssp. napobrassica (L.) Hanelt] is reported to be an excellent source of clubroot (Plasmodiophora brassicae) resistance genes. In this study, 124 rutabaga accessions from the Nordic countries (Norway, Sweden, Finland, Denmark, and Iceland) were evaluated for their reaction to five single-spore isolates representing P. brassicae pathotypes 2F, 3H, 5I, 6M, and 8N and 12 field isolates representing pathotypes 2B, 3A, 3O, 5C, 5G, 5K, 5L, 5X (two is ...[more]

PMID: 32595668

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Project description:BackgroundRutabaga or swede (Brassica napus ssp. napobrassica (L.) Hanelt) varies in root and leaf shape and colour, flesh colour, foliage growth habits, maturity date, seed quality parameters, disease resistance and other traits. Despite these morphological differences, no in-depth molecular analyses of genetic diversity have been conducted in this crop. Understanding this diversity is important for conservation and broadening the use of this resource.ResultsThis study investigated the genetic diversity within and among 124 rutabaga accessions from five Nordic countries (Norway, Sweden, Finland, Denmark and Iceland) using a 15 K single nucleotide polymorphism (SNP) Brassica array. After excluding markers that did not amplify genomic DNA, monomorphic and low coverage site markers, the accessions were analyzedwith 6861 SNP markers. Allelic frequency statistics, including polymorphism information content (PIC), minor allele frequency (MAF) and mean expected heterozygosity ([Formula: see text]e) and population differentiation statistics such as Wright's F-statistics (FST) and analysis of molecular variance (AMOVA) indicated that the rutabaga accessions from Norway, Sweden, Finland and Denmark were not genetically different from each other. In contrast, accessions from these countries were significantly different from the accessions from Iceland (P < 0.05). Bayesian analysis with the software STRUCTURE placed 66.9% of the rutabaga accessions into three to four clusters, while the remaining 33.1% constituted admixtures. Three multivariate analyses: principal coordinate analysis (PCoA), the unweighted pair group method with arithmetic mean (UPGMA) and neighbour-joining (NJ) clustering methods grouped the 124 accessions into four to six subgroups.ConclusionOverall, the correlation of the accessions with their geographic origin was very low, except for the accessions from Iceland. Thus, Icelandic rutabaga accessions can offer valuable germplasm for crop improvement.

Project description:Interspecific hybridization is a powerful tool for improvement of crop species, it has the potential to broaden the genetic base and create new plant forms for breeding programs. Synthetic allopolyploid is a widely-used model for the study of genetic recombination and fixed heterosis in Brassica. In Brassica napus breeding, identification and introgression of new sources of clubroot resistance trait from wild or related species into it by hybridization is a long-term crop management strategy for clubroot disease. Radish (Raphanus sativus L.) is a close relative of the Brassica and most radish accessions are immune to the clubroot disease. A synthesized allotetraploid Brassicoraphanus (RRCC, 2n = 36) between R. sativus cv. HQ-04 (2n = 18, RR) and Brassica oleracea var. alboglabra (L.H Bailey) (2n = 18, CC) proved resistant of multiple clubroot disease pathogen P. brassicae. To predict the possibility to transfer the clubroot resistance trait from the RR subgenome of allotetraploid Brassicoraphanus (RRCC, 2n = 36) into Brassica napus (AACC, 2n = 38), we analyzed the frequency of chromosome pairings in the F1 hybrids produced from a cross between B. napus cv. HS5 and the allotetraploid, characterize the genomic composition of some backcrossed progeny (BC1) using GISH, BAC-FISH and AFLP techniques. The level of intergenomic pairing between A and R genomes in the F1 hybrid was high, allosyndetic bivalents formed in 73.53% PMCs indicative of significant level of homeologous recombination between two genomes and high probability of incorporating chromosomal segments/genes from R-genome into A/C-genomes. The BC1 plants inherited variant extra R chromosomes or fragments from allotetraploid as revealed by GISH and AFLP analysis. 13.51% BC2 individuals were resistant to clubroot disease, and several resistance lines had high pollen fertility, Overall, the genetic material presented in this work represents a potential new genetic resource for practical use in breeding B. napus clubroot resistant cultivars.

Project description:Rutabaga, also known as swede and scientifically classified as Brassica napus napobrassica, is a biennial edible root vegetable that belongs to the Brassica genus and is widely cultivated in North Europe and North America. The present study highlights both the phytochemical profile and the in vitro biological properties of rutabaga seed extracts obtained through maceration using solvents of increasing polarity, namely, cyclohexane (CYHA), dichloromethane (DCM), ethyl acetate (EtOAc), methanol (MeOH), and water (H2O). HPLC-DAD was used to identify and quantify phenolic compounds, while volatile compounds were detected using GC-MS. The in vitro antioxidant capacity of the rutabaga seed extracts was evaluated through DPPH free radical scavenging activity. The in vitro anti-inflammatory activity (15-lipoxygenase (15-LOX) enzyme) was determined spectrophotometrically at the same concentration. Additionally, the cytotoxicity of the seed extracts was evaluated against human colon adenocarcinoma cells (Caco-2) and human embryonic kidney cells (HEK-293) using the MTT assay. The rutabaga seed extracts obtained from EtOAc, MeOH, and H2O were particularly rich in reducing sugars, ranging from 189.87 to 473.75 mg/g DW. The MeOH extract displayed the highest concentration of both sugars and polyphenols. Phytochemically, the HPLC-DAD analysis revealed the presence of four phenolic compounds in the tested extracts, including (±) synephrine, gallic acid, p-coumaric acid, and trans-ferulic acid, newly discovered in rutabaga organs. Moreover, a total of ten volatile compounds were identified through GC-MS analysis, both before and after derivatization. At a concentration of 50 µg/mL, the methanol extract exhibited high antioxidant activity with 52.95% inhibition, while CYHA, DCM, and EtOAc exhibited moderate anti-15-LOX activity with less than 30% inhibition. Except for DCM and aqueous extracts, rutabaga seeds did not exhibit any anti-proliferative potential against Caco-2 cell lines. Interestingly, no cytotoxicity was registered for any of the seed extracts against the normal cell line HEK-293. Overall, the obtained data highlight the potential utilization of rutabaga seeds as a source of bioactive compounds in various fields, including pharmaceuticals, nutraceuticals, and functional foods.

Project description:Sustainable canola production is essential to meet growing human demands for vegetable oil, biodiesel, and meal for stock feed markets. Blackleg, caused by the fungal pathogen, Leptosphaeria maculans is a devastating disease that can lead to significant yield loss in many canola production regions worldwide. Breakdown of race-specific resistance to L. maculans in commercial cultivars poses a constant threat to the canola industry. To identify new alleles, especially for quantitative resistance (QR), we analyzed 177 doubled haploid (DH) lines derived from an RP04/Ag-Outback cross. DH lines were evaluated for QR under field conditions in three experiments conducted at Wagga Wagga (2013, 2014) and Lake Green (2015), and under shade house conditions using the 'ascospore shower' test. DH lines were also characterized for qualitative R gene-mediated resistance via cotyledon tests with two differential single spore isolates, IBCN17 and IBCN76, under glasshouse conditions. Based on 18,851 DArTseq markers, a linkage map representing 2,019 unique marker bins was constructed and then utilized for QTL detection. Marker regression analysis identified 22 significant marker associations for resistance, allowing identification of two race-specific resistance R genes, Rlm3 and Rlm4, and 21 marker associations for QR loci. At least three SNP associations for QR were repeatedly detected on chromosomes A03, A07 and C04 across phenotyping environments. Physical mapping of markers linked with these consistent QR loci on the B. napus genome assembly revealed their localization in close proximity of the candidate genes of B. napus BnaA03g26760D (A03), BnaA07g20240D (A07) and BnaC04g02040D (C04). Annotation of these candidate genes revealed their association with protein kinase and jumonji proteins implicated in defense resistance. Both Rlm3 and Rlm4 genes identified in this DH population did not show any association with resistance loci detected under either field and/or shade house conditions (ascospore shower) suggesting that both genes are ineffective in conferring resistance to L. maculans in Australian field conditions. Taken together, our study identified sequence-based molecular markers for dissecting R and QR loci to L. maculans in a canola DH population from the RP04/Ag-Outback cross.

Project description:Rapeseed (Brassica napus L.) is the world's third most important edible oilseed crop after soybean and palm. The clubroot disease caused by Plasmodiophora brassicae poses a significant risk and causes substantial yield losses in rapeseed. In this study, 13 endophytic fungal strains were isolated from the healthy roots of rapeseed (B. napus) grown in a clubroot-infested field and molecularly identified. Based on germination inhibition of resting spores of P. brassicae, two endophytic fungal antagonists, Trichoderma spp. ReTk1 and ReTv2 were selected to evaluate their potential for plant growth promotion and biocontrol of P. brassicae. The Trichoderma isolates were applied as a soil drench (1×107 spore/g soil) to a planting mix and field soil, in which plants were grown under non-infested and P. brassicae-infested (2×106 spore/g soil) conditions. The endophytic fungi were able to promote plant growth, significantly increasing shoot and root length, leaf diameter, and biomass production (shoots and root weight) both in the absence or presence of P. brassicae. The single and dual treatments with the endophytes were equally effective in significantly decreasing the root-hair infection, root index, and clubroot severity index. Both ReTk1 and ReTv2 inhibited the germination of resting spores of P. brassicae in root exudates. Moreover, the endophytic fungi colonized the roots of rapeseed extensively and possibly induced host resistance by up-regulated expression of defense-related genes involved in jasmonate (BnOPR2), ethylene (BnACO and BnSAM3), phenylpropanoid (BnOPCL and BnCCR), auxin (BnAAO1) and salicylic acid (BnPR2) pathways. Based on these findings, it is evident that the rapeseed root endophytes Trichoderma spp. ReTk1 and ReTv2 could suppress the gall formation on rapeseed roots via antibiosis, induced systemic resistance (ISR), and/or systemic acquired resistance (SAR). According to our knowledge, this is the first report of the endophytic Trichoderma spp. isolated from root tissues of healthy rapeseed plants (B. napus.), promoting plant growth and reducing clubroot severity.

Dataset Information

Genome-Wide Mapping of Loci Associated With Resistance to Clubroot in Brassica napus ssp. napobrassica (Rutabaga) Accessions From Nordic Countries.

Publications

Genome-Wide Mapping of Loci Associated With Resistance to Clubroot in <i>Brassica napus</i> ssp. <i>napobrassica</i> (Rutabaga) Accessions From Nordic Countries.

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