Person: Singh, P.K.
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Singh
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P.K.
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Singh, P.K.
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0000-0003-4610-3120 48 results
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- Genetic analysis and mapping of seedling resistance to Septoria tritici blotch in 'Steele-ND'/'ND 735' bread wheat population(Akadémiai Kiadó, 2013) Mergoum, M.; Harilal, V.E.; Singh, P.K.; Adhikari, T.B.; Kumar, A.; Ghavami, F.; Elias, E.; Alamri, M.S.; Kianian, S.F.
Publication - Race structure and distribution of Pyrenophora tritici-repentis in Tunisia(Universitá Degli Studi Firenze, 2019) Laribi, M.; Gamba, F.M.; Hassine, M.; Singh, P.K.; Yahyaoui, A.; Sassi, K.
Publication - A white paper on global wheat health based on scenario development and analysis(American Phytopathological Society (APS), 2017) Savary, S.; Djurle, A.; Yuen, J.E.; Ficke, A.; Rossi, V.; Esker, P.D.; Fernandes, J.M.C.; Ponte, E.M.; Kumar, J.; Madden, L.V.; Paul, P.; McRoberts, N.; Singh, P.K.; Huber, L.; Pope de Vallavielle, C.; Saint-Jean, S.; Willocquet, L.Scenario analysis constitutes a useful approach to synthesize knowledge and derive hypotheses in the case of complex systems that are documented with mainly qualitative or very diverse information. In this article, a framework for scenario analysis is designed and then, applied to global wheat health within a timeframe from today to 2050. Scenario analysis entails the choice of settings, the definition of scenarios of change, and the analysis of outcomes of these scenarios in the chosen settings. Three idealized agrosystems, representing a large fraction of the global diversity of wheat-based agrosystems, are considered, which represent the settings of the analysis. Several components of global changes are considered in their consequences on global wheat health: climate change and climate variability, nitrogen fertilizer use, tillage, crop rotation, pesticide use, and the deployment of host plant resistances. Each idealized agrosystem is associated with a scenario of change that considers first, a production situation and its dynamics, and second, the impacts of the evolving production situation on the evolution of crop health. Crop health is represented by six functional groups of wheat pathogens: the pathogens associated with Fusarium head blight; biotrophic fungi, Septoria-like fungi, necrotrophic fungi, soilborne pathogens, and insect-transmitted viruses. The analysis of scenario outcomes is conducted along a risk-analytical pattern, which involves risk probabilities represented by categorized probability levels of disease epidemics, and risk magnitudes represented by categorized levels of crop losses resulting from these levels of epidemics within each production situation. The results from this scenario analysis suggest an overall increase of risk probabilities and magnitudes in the three idealized agrosystems. Changes in risk probability or magnitude however vary with the agrosystem and the functional groups of pathogens. We discuss the effects of global changes on the six functional groups, in terms of their epidemiology and of the crop losses they cause. Scenario analysis enables qualitative analysis of complex systems, such as plant pathosystems that are evolving in response to global changes, including climate change and technology shifts. It also provides a useful framework for quantitative simulation modeling analysis for plant disease epidemiology.
Publication - A wheat chromosome 5AL region confers seedling resistance to both tan spot and Septoria nodorum blotch in two mapping populations(Elsevier, 2019) Wenjing Hua; Xinyao He; Dreisigacker, S.; Sansaloni, C.; Juliana, P.; Singh, P.K.Tan spot (TS) and Septoria nodorum blotch (SNB), caused by Pyrenophora tritici-repentis and Parastagonospora nodorum, respectively, are important fungal leaf-spotting diseases of wheat that cause significant losses in grain yield. In this study, two recombinant inbred line populations, ‘Bartai’ × ‘Ciano T79’ (referred to as B × C) and ‘Cascabel’ × ‘Ciano T79’ (C × C) were tested for TS and SNB response in order to determine the genetic basis of seedling resistance. Genotyping was performed with the DArTseq genotyping-by-sequencing (GBS) platform. A chromosome region on 5AL conferred resistance to TS and SNB in both populations, but the effects were larger in B × C (R2 = 11.2%–16.8%) than in C × C (R2 = 2.5%–9.7%). Additionally, the chromosome region on 5BL (presumably Tsn1) was significant for both TS and SNB in B × C but not in C × C. Quantitative trait loci (QTL) with minor effects were identified on chromosomes 1B, 2A, 2B, 3A, 3B, 4D, 5A, 5B, 5D, 6B, and 6D. The two CIMMYT breeding lines ‘Bartai’ and ‘Cascabel’ contributed resistance alleles at both 5AL and 5BL QTL mentioned above. The QTL on 5AL showed linkage with the Vrn-A1 locus, whereas the vrn-A1 allele conferring lateness was associated with resistance to TS and SNB.
Publication - The use of pentaploid crosses for the introgression of Amblyopyrum muticum and D-genome chromosome segments into durum wheat(Frontiers, 2019) Othmeni, M.; Grewal, S.; Hubbart-Edwards, S.; Cai-Yun Yang; Scholefield, D.; Ashling, S.; Yahyaoui, A.; Gustafson, P.; Singh, P.K.; King, I.P.; King, J.The wild relatives of wheat provide an important source of genetic variation for wheat improvement. Much of the work in the past aimed at transferring genetic variation from wild relatives into wheat has relied on the exploitation of the ph1b mutant, located on the long arm of chromosome 5B. This mutation allows homologous recombination to occur between chromosomes from related but different genomes, e.g. between the chromosomes of wheat and related chromosomes from a wild relative resulting in the generation of interspecific recombinant chromosomes. However, the ph1b mutant also enables recombination to occur between the homologous genomes of wheat, e.g. A/B, A/D, B/D, resulting in the generation of wheat intergenomic recombinant chromosomes. In this work we report on the presence of wheat intergenomic recombinants in the genomic background of hexaploid wheat/Amblyopyrum muticum introgression lines. The transfer of genomic rearrangements involving the D-genome through pentaploid crosses provides a strategy by which the D-genome of wheat can be introgressed into durum wheat. Hence, a pentaploid crossing strategy was used to transfer D-genome segments, introgressed with either the A- and/or the B-genome, into the tetraploid background of two durum wheat genotypes Karim and Om Rabi 5 in either the presence or absence of different Am. muticum (2n = 2x = 14, TT) introgressions. Introgressions were monitored in backcross generations to the durum wheat parents via multi-color genomic in situ hybridization (mc-GISH). Tetraploid lines carrying homozygous D-genome introgressions, as well as simultaneous homozygous D- and T-genome introgressions, were developed. Introgression lines were characterized via Kompetitive Allele-Specific PCR (KASP) markers and multi-color fluorescence in situ hybridization (FISH). Results showed that new wheat sub-genomic translocations were generated at each generation in progeny that carried any Am. muticum chromosome introgression irrespective of the linkage group that the segment was derived from. The highest frequencies of homologous recombination were observed between the A- and the D-genomes. Results indicated that the genotype Karim had a higher tolerance to genomic rearrangements and T-genome introgressions compared to Om Rabi 5. This indicates the importance of the selection of the parental genotype when attempting to transfer/develop introgressions into durum wheat from pentaploid crosses.
Publication - QTL mapping and transcriptome analysis to identify differentially expressed genes induced by Septoria tritici blotch disease of wheat(MDPI, 2019) Odilbekov, F.; Xinyao He; Armoniené, R.; Saripella, G.V.; Henriksson, T.; Singh, P.K.; Chawade, A.Resistance to Septoria tritici blotch (STB) is an economically important trait in many wheat-breeding programs across the world. Several quantitative trait loci (QTL) for STB resistance were identified in wheat but due to the dynamic pathogen population it is necessary to continuously identify new resistance genes/QTL and determine the underlying resistance mechanism. In this work, we integrated QTL mapping and transcriptome profiling to identify candidate genes underlying QTL associated with STB resistance in bread wheat at the seedling stage. The results revealed four QTL on chromosomes 1BS, 1BL, 3AS and 3DL for STB resistance. Among these, two QTL on 2BL and 3DL were mapped for chlorosis, necrosis and pycnidia while the other two on 1BS and 3AS were associated with necrosis and pycnidia. Among the four identified QTL, genes were identified in three QTL (1BS, 2BL and 3DL). In total, 238 differentially expressed genes (DEGs) were localized in 1BS, 16 DEGs in 2BL and 80 DEGs in 3DL QTL region respectively. F-box protein, NBS-LRR disease resistance genes and receptor-like protein kinase were the most over-represented. The results emphasize the importance of integrating QTL and transcriptome analysis to accelerate the identification of key genes underlying the traits of interest.
Publication - Hydrogen peroxide prompted lignification affects pathogenicity of hemi-biotrophic pathogen Bipolaris sorokiniana to wheat(Korean Society of Plant Pathology, 2019) Poudel, A.; Sudhir Navathe; Chand, R.; Mishra, V.K.; Singh, P.K.; Joshi, A.K.Spot blotch caused by Bipolaris sorokiniana has spread to more than 9 million ha of wheat in the warm, humid areas of the Eastern Gangetic Plains (EGP) of South Asia and is a disease of major concern in other similar wheat growing regions worldwide. Differential lignin content in resistant and susceptible genotypes and its association with free radicals such as hydrogen peroxide (H2O2), superoxide (O2−) and hydroxyl radical (OH−) were studied after inoculation under field conditions for two consecutive years. H2O2 significantly influenced lignin content in flag leaves, whereas there was a negative correlation among lignin and H2O2 to the Area Under Disease Progress Curve (AUDPC). The production of H2O2 was higher in the resistant genotypes than susceptible ones. The O2− and OH− positively correlated with AUDPC but negatively with lignin content. This study illustrates that H2O2 has a vital role in prompting lignification and thereby resistance to spot blotch in wheat. We used cluster analysis to separate the resistant and susceptible genotypes by phenotypic and biochemical traits. H2O2 associated lignin production significantly reduced the number of appressoria and penetration pegs. We visualized the effect of lignin in disease resistance using differential histochemical staining of tissue from resistant and susceptible genotypes, which shows the variable accumulation of hydrogen peroxide and lignin around penetration sites.
Publication - Characterization of QTLs for seedling resistance to tan spot and Septoria nodorum blotch in the PBW343/Kenya Nyangumi wheat recombinant inbred lines population(MDPI, 2019) Singh, P.K.; Singh, S.; Zhiying Deng; Xinyao He; Kehel, Z.; Singh, R.P.
Publication - Genome wide association study of karnal bunt resistance in a wheat germplasm collection from Afghanistan(MDPI, 2019) Gupta, V.; Xinyao He; Kumar, N.; Fuentes Dávila, G.; Sharma, R.; Dreisigacker, S.; Juliana, P.; Ataei, N.; Singh, P.K.Karnal bunt disease of wheat, caused by the fungus Neovossia indica, is one of the most important challenges to the grain industry as it affects the grain quality and also restricts the international movement of infected grain. It is a seed-, soil- and airborne disease with limited effect of chemical control. Currently, this disease is contained through the deployment of host resistance but further improvement is limited as only a few genotypes have been found to carry partial resistance. To identify genomic regions responsible for resistance in a set of 339 wheat accessions, genome-wide association study (GWAS) was undertaken using the DArTSeq® technology, in which 18 genomic regions for Karnal bunt resistance were identified, explaining 5–20% of the phenotypic variation. The identified quantitative trait loci (QTL) on chromosome 2BL showed consistently significant effects across all four experiments, whereas another QTL on 5BL was significant in three experiments. Additional QTLs were mapped on chromosomes 1DL, 2DL, 4AL, 5AS, 6BL, 6BS, 7BS and 7DL that have not been mapped previously, and on chromosomes 4B, 5AL, 5BL and 6BS, which have been reported in previous studies. Germplasm with less than 1% Karnal bunt infection have been identified and can be used for resistance breeding. The SNP markers linked to the genomic regions conferring resistance to Karnal bunt could be used to improve Karnal bunt resistance through marker-assisted selection.
Publication - Genetics for low correlation between Fusarium head blight disease and deoxynivalenol (DON) content in a bread wheat mapping population(Springer, 2019) Xinyao He; Dreisigacker, S.; Singh, R.P.; Singh, P.K.Key message: Two QTL with major effects on DON content reduction were identified on chromosomes 3BL and 3DL, with the former showing minor and the latter showing no effects on FHB resistance. Abstract: Deoxynivalenol (DON) contamination in food and feed is a major concern regarding Fusarium head blight (FHB) infection in wheat. However, relatively less attention has been paid on DON compared to FHB. In this study, a FHB-susceptible cultivar ‘NASMA’ was hybridized with a FHB-resistant CIMMYT breeding line ‘IAS20*5/H567.71’ to generate 197 recombinant inbred lines. The population was phenotyped for FHB and associated traits including DON accumulation in spray-inoculated field experiments at CIMMYT-Mexico across four years. Genotyping was performed by using the Illumina Infinium 15 K Beadchip and SSR markers. QTL mapping results indicated that the field FHB resistance was mainly controlled by QTL at Rht-D1 and Vrn-A1, along with a few minor QTL. For DON content, two major QTL were identified: the first located on chromosome 3BL (R2 of 16–24%), showing minor effects on FHB, and the second was on chromosome 3DL (R2 of 10–15%), exhibiting no effect on FHB resistance. It is likely that both DON QTL are new based on comparison with previous studies. This study indicates that resistance to DON accumulation and FHB disease could involve different genes, and the utilization of the two DON QTL in breeding could be helpful in further reducing DON contamination in food and feed.
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