I am an agricultural Engineer from Colombia with a master degree on plant pathology. Now I am beginning my PhD studies in plant pathology at the University of Alberta.
I am a passionate for plant pathology, whose emphasis is in clubroot disease. I have been working with my research group in Colombia at the Universidad Nacional de Colombia in clubroot disease’s biological control, P. brassicae (the causal agent of clubroot disease) spread and distribution in field and some epidemiological topics looking forward to developing a risk assessment strategy for cruciferous crops affected by the disease. Now I am also working in the yield losses assessment in canola crops in Canada with my research group at the University of Alberta.
Different disease strategies which are being conducted nowadays for this disease management in field
Clubroot disease management is quite difficult, since the causal agent (Plasmodiophora brassicae) is a protozoan which is able to produce resting spores which can keep viable in soil in absence of a suitable host for even 20 years. This disease is one of the most important issues in different cruciferous crops such as broccoli, cauliflower, cabbage and canola. Clubroot disease management is only efficient now by avoiding the disease entrance to the field and the usage of resistant materials, however, it is not the best strategy, since the resistance breakdown has been broadly observed in a short term, that is why an IPM is necesary and in this pinboard you will find the latest on this topic
Abstract: Clubroot disease caused by the soil-borne pathogen Plasmodiophora brassicae Woronin is a major threat to the production of Brassica crops worldwide. The European winter canola cv. ‘Mendel’ shows resistance to many P. brassicae isolates including pathotypes 3, 5, 6 and 8 that are prevalent in Canada. To introgress clubroot resistance (CR) into Canadian spring Brassica napus canola, crosses between Canadian spring and European winter B. napus canola cv. ‘Mendel’ were made and several resistant lines were developed through pedigree breeding. Two of the resistant lines were further crossed with the clubroot susceptible spring canola line A07-26NR to produce two doubled haploid (DH) populations from nine F1 plants. Segregation for resistance followed a 1:1 ratio for resistant and susceptible phenotypes suggesting that a single Mendelian gene is involved in the control of resistance to P. brassicae single spore isolate SACAN-ss1 (pathotype 3) in the DH population where the ‘favourable allele’ for resistance is derived from the cv. ‘Mendel’. Genetic and physical mapping study positioned five previously described CR loci (CRk, Crr3, CRb, CRa and CRb Kato ) on the B. rapa chromosome A3, and identified twelve markers (1.5–2.0 % recombination) from the genomic region that houses the CRa and CRb Kato loci to be associated with the resistance derived from ‘Mendel’. The identified markers can be used in breeding as well as pyramiding of multiple clubroot resistance genes.
Pub.: 07 Jun '16, Pinned: 01 Jul '17
Abstract: Clubroot is a soilborne disease that severely infects cruciferous species. Pak choi (Brassica rapa subsp. chinensis) is an economically important cruciferous crop cultivated throughout the world. However, no clubroot‐resistant germplasms have been identified in pak choi to date. To improve disease resistance, we used marker‐assisted selection (MAS) to introgress the clubroot resistance (CR) trait from the ‘CCR13685’ Chinese cabbage (B. rapa subsp. pekinensis) inbred line into an elite pak choi inbred line, ‘GHQ11021’. Genetic analysis of F2 and BC1 progeny showed that CR of ‘CCR13685’ was controlled by a single dominant gene. We designed nine candidate sequence‐characterized amplified region markers, K‐1 to K‐9, based on two molecular markers linked to the CR gene. We found that K‐3 co‐segregated with CR and an inoculation test confirmed that K‐3 could be used for MAS. Two introgression lines, BC3‐1‐4 and BC3‐2‐18, were developed using K‐3 for foreground selection. These lines displayed the same phenotypic properties as ‘GHQ11021’, but were highly resistant to clubroot, indicating that the CR gene of ‘CCR13685’ had been successfully introduced into pak choi.
Pub.: 24 May '16, Pinned: 01 Jul '17
Abstract: This study was conducted to optimize the cultural medium and conditions for production of antifungal substances by Streptomyces platensis 3-10 and to evaluate its efficacy in suppressing Plasmodiophora brassicae (PB), the causal agent for clubroot of oilseed rape. The optimization was done using the one-factor-at-a-time (OFAT) method, followed by orthogonal designing. The optimized medium contained starch at 3% (w/v), peptone at 0.75%, yeast extract at 0.025%, soybean meal at 1% (w/v) and minor/trace elements (K+, Mg2+, Mn2+, Zn2+), initial pH 6.5. After incubation in this medium at 28°C/150 rpm for 72 h, isolate 3-10 showed high antifungal activity. The cultural filtrates (CF3-10) produced an average inhibition-zone diameter of 50 mm against Aspergillus niger. The live spores and metabolites of 3-10 in CF3-10 or its crude extracts (CE3-10) suppressed PB infection of oilseed rape roots by 3 to 83%, compared to the treatment with PB alone. The efficacy was positively correlated (correlation co-efficiency: 0.9526–0.9873, P < 0.05) to the applied dose of each active component. Germination of PB resting spores was inhibited by 75 and 80% by CE3-10 (1,000 μg/mL, w/v) and CF3-10 (5%, v/v), respectively. These findings suggest that S. platensis 3-10 is a promising biocontrol agent against PB.
Pub.: 22 Jun '16, Pinned: 01 Jul '17
Abstract: Clubroot, caused by the protozoan parasite Plasmodiophora brassicae Woronin, is one of the most damaging diseases of Brassica napus worldwide. Resistant plant material is valuable for cultivation in all areas of high incidence of the disease and intensive growth of oilseed rape. We have evaluated clubroot resistance, plant morphology and seed quality in 15 lines of an F4 generation and selected six lines of F5 generation of interspecific hybrids obtained from a cross between a male sterile line of B. napus ‘MS8’, selected from resynthesized oilseed rape (B. rapa ssp. chinensis × B. oleracea var. gemmifera) and an ecotype of B. rapa ssp. pekinensis. Clubroot resistance was evaluated using a bioassay with P1-P5 pathotypes of P. brassicae (according to the classification of Somé et al. 1996). The resistance to the pathotype P1 was successfully fixed in the F5 generation, and improved in some lines in respect to the pathotypes P2-P4. The resistance to P1 and the other tested pathotypes was not linked. Characterization of plant material included recent techniques of FISH and BAC-FISH with a special focus on the analysis of ribosomal DNA (rDNA) of selected individuals. Two hybrid lines combined high levels of resistance with appropriate plant morphology, good seed quality traits and a stable chromosome number and arrangement. Recent techniques of ‘chromosome painting’ provided good insight into chromosome organization in the hybrids obtained, and offered opportunities of further improvement of the breeding process.
Pub.: 04 Jul '16, Pinned: 01 Jul '17
Abstract: Clubroot, caused by the plasmodiophorid pathogen Plasmodiophora brassicae, is one of the most serious diseases on Brassica crops worldwide and a major threat to canola production in western Canada. Host resistance is the key strategy for clubroot management on canola. Several clubroot resistance (CR) genes have been identified, but the mechanisms associated with these CR genes are poorly understood. In the current study, a label-free shotgun proteomic approach was used to profile and compare the proteomes of Brassica rapa carrying and not carrying the CR gene Rcr1 in response to P. brassicae infection. A total of 527 differentially accumulated proteins (DAPs) were identified between the resistant (with Rcr1) and susceptible (without Rcr1) samples, and functional annotation of these DAPs indicates that the perception of P. brassicae and activation of defense responses are triggered via an unique signaling pathway distinct from common modes of recognition receptors reported with many other plant-pathogen interactions; this pathway appears to act in a calcium-independent manner through a not-well-defined cascade of mitogen-activated protein kinases and may require the ubiquitin-26S proteasome found to be related to abiotic stresses, especially the cold-stress tolerance in other studies. Both up-regulation of defense-related and down-regulation of pathogenicity-related metabolism was observed in plants carrying Rcr1, and these functions may all contribute to the CR mediated by Rcr1. These results, combined with those of transcriptomic analysis reported earlier, improved our understanding of molecular mechanisms associated with Rcr1 and CR at large, and identified candidate metabolites or pathways related to specific resistance mechanisms. Deploying CR genes with different modes of action may help improve the durability of CR.
Pub.: 28 Jul '16, Pinned: 01 Jul '17
Abstract: Clubroot significantly affects plants of the Brassicaceae family and is one of the main diseases causing serious losses in B. napus yield. Few studies have investigated the clubroot-resistance mechanism in B. napus. Identification of clubroot-resistant genes may be used in clubroot-resistant breeding, as well as to elucidate the molecular mechanism behind B. napus clubroot-resistance. We used three B. napus transcriptome samples to construct a transcriptome sequencing library by using Illumina HiSeq™ 2000 sequencing and bioinformatic analysis. In total, 171 million high-quality reads were obtained, containing 96,149 unigenes of N50-value. We aligned the obtained unigenes with the Nr, Swiss-Prot, clusters of orthologous groups, and gene ontology databases and annotated their functions. In the Kyoto encyclopedia of genes and genomes database, 25,033 unigenes (26.04%) were assigned to 124 pathways. Many genes, including broad-spectrum disease-resistance genes, specific clubroot-resistant genes, and genes related to indole-3-acetic acid (IAA) signal transduction, cytokinin synthesis, and myrosinase synthesis in the Huashuang 3 variety of B. napus were found to be related to clubroot-resistance. The effective clubroot-resistance observed in this variety may be due to the induced increased expression of these disease-resistant genes and strong inhibition of the IAA signal transduction, cytokinin synthesis, and myrosinase synthesis. The homology observed between unigenes 0048482, 0061770 and the Crr1 gene shared 94% nucleotide similarity. Furthermore, unigene 0061770 could have originated from an inversion of the Crr1 5'-end sequence.
Pub.: 16 Aug '16, Pinned: 01 Jul '17
Abstract: Clubroot disease, caused by Plasmodiophora brassicae, is a threat to the production of Brassica crops including oilseed B. napus. In Canada, several pathotypes of this pathogen, such as pathotypes 2, 3, 5, 6, and 8, were identified, and resistance to these pathotypes was found in a rutabaga (B. napus var. napobrassica) genotype. In this paper, we report the genetic basis and molecular mapping of this resistance by use of F2, backcross (BC1), and doubled haploid (DH) populations generated from crossing of this rutabaga line to a susceptible spring B. napus canola line. The F1, F2, and BC1 populations were evaluated for resistance to pathotype 3, and the DH population was evaluated for resistance to pathotypes 2, 3, 5, 6, and 8. A 3:1 segregation in F2 and a 1:1 segregation in BC1 were found for resistance to pathotype 3, and a 1:1 segregation was found in the DH population for resistance to all pathotypes. Molecular mapping by using the DH population identified a genomic region on chromosome A8 carrying resistance to all five pathotypes. This suggests that a single gene or a cluster of genes, located in this genomic region, is involved in the control of resistance to these pathotypes.
Pub.: 24 Aug '16, Pinned: 01 Jul '17
Abstract: Botrytis-induced kinase1 (BIK1), a receptor-like cytoplasmic kinase, plays an important role in resistance against pathogens and insects in Arabidopsis thaliana. However, it remains unknown whether BIK1 functions against Plasmodiophora brassicae, an obligate biotrophic protist that attacks cruciferous plants and induces gall formation on roots. Here, we investigated the potential roles of receptors FLS2, BAK1, and BIK1 in the infection of P. brassicae cruciferous plants. Wild-type plants, fls2, and bak1 mutants showed typical symptom on roots, and the galls were filled with large quantities of resting spores, while bik1 mutant plants exhibited strong resistance to P. brassicae. Compared with that of the wild-type plants, the root hair and cortical infection rate of bik1 mutant were significantly reduced by about 40-50%. A considerable portion of bik1 roots failed to form typical galls. Even if some small galls were formed, they were filled with multinucleate secondary plasmodia. The bik1 plants accumulated less reactive oxygen species (ROS) at infected roots than other mutants and wild-type plants. Exogenous salicylic acid (SA) treatment alleviated the clubroot symptoms in wild-type plants, and the expression of the SA signaling marker gene PR1 was significantly increased in bik1. Both sid2 (salicylic acid induction-deficient 2) and npr1-1 [non-expresser of PR genes that regulate systemic acquired resistance (SAR)] mutants showed increased susceptibility to P. brassicae compared with wild-type plants. These results suggest that the resistance of bik1 to P. brassicae is possibly mediated by SA inducible mechanisms.
Pub.: 30 Sep '16, Pinned: 01 Jul '17
Abstract: The mixtures of 10 % cyazofamid SC and 25 % methiadinil SC were selected at different concentrations in root irrigation treatment of cruciferous crops and compared with 10 % cyazofamid SC to evaluate the chemical control of clubroot disease in field trials located in Dayi County (Sichuan Province, China) and Jiulong County (Sichuan Province, China), respectively. The results indicated that the effects of the test mixtures were better than that of a single treatment of 10 % cyazofamid SC. The mixture containing an effective ingredient dosage of 30 mg/L cyazofamid + 150 mg/L methiadinil was found to have the greatest effect. The combination of cyazofamid and methiadinil was effective in the control of clubroot and can be recommended for the treatment of soils highly infested with Plasmodiophora brassicae. The mixture is also effective in increasing crop yields.
Pub.: 24 Oct '16, Pinned: 01 Jul '17
Abstract: Nitrogen levels can modulate the effectiveness of clubroot resistance in an isolate- and host-specific manner. While the same QTL were detected under high and low nitrogen, their effects were altered. Clubroot, caused by Plasmodiophora brassicae, is one of the most damaging diseases of oilseed rape and is known to be affected by nitrogen fertilization. However, the genetic factors involved in clubroot resistance have not been characterized under nitrogen-limiting conditions. This study aimed to assess the variability of clubroot resistance under different nitrogen levels and to characterize the impact of nitrogen supply on genetic resistance factors. Linkage analyses and a genome-wide association study were conducted to detect QTL for clubroot resistance and evaluate their sensitivity to nitrogen. The clubroot response of a set of 92 diverse oilseed rape accessions and 108 lines derived from a cross between 'Darmor-bzh' (resistant) and 'Yudal' (susceptible) was studied in the greenhouse under high- and low-nitrogen conditions, following inoculation with the P. brassicae isolates eH and K92-16. Resistance to each isolate was controlled by a major QTL and a few small-effects QTL. While the same QTL were detected under both high and low nitrogen, their effects were altered. Clubroot resistance to isolate eH, but not K92-16, was greater under a low-N supply versus a high-N supply. New sources of resistance were found among the oilseed rape accessions under both low and high-N conditions. The results are discussed relative to the literature and from a crop improvement perspective.
Pub.: 05 Jan '17, Pinned: 01 Jul '17
Abstract: 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.
Pub.: 16 May '17, Pinned: 01 Jul '17