The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
S Nagarajan - One of the best experts on this subject based on the ideXlab platform.
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Sources of resistance in wheat and triticale against Loose Smut caused by Ustilago segatum tritici.
Indian phytopathology, 2020Co-Authors: V C Sinha, S Nagarajan, L. B. Goel, M. S. Beniwal, S S Karwasra, A S Grewal, Jagdish KumarAbstract:Loose Smut (Ustilago segatum var. tritici) is an important disease of wheat in the northern belt of India. There has been an increase in the incidence of the disease in the past two decades. None of the commercial wheat varieties is resistant to this disease. Being internally seedborne, it is easily amenable to systemic fungicides as dry seed treatment, but due to the high cost of chemical seed treatment, breeding Smut resistant varieties remains the ideal method to contain the disease. Wheat and triticale varieties were subjected to artificial testing against the Loose Smut pathogen during 1987-94 at the Ludhiana (Indian Punjab) and Hisar (Haryana) centres. Out of large number of entries tested (c. 1000), PBW65, HDR-70, VL421 and WL 410 were either free or only exhibited trace infection during the past 8 years. Nine CIMMYT lines also exhibited good Smut resistance under Indian conditions.
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Efficacy of Trichoderma viride in controlling the Loose Smut of wheat caused by Ustilago segetum var. tritici at multilocation.
Journal of Biological Control, 2020Co-Authors: Dhananjaya P. Singh, S Nagarajan, L. B. Goel, D.v. Singh, Jagmohan Kumar, Dheeraj Singh, Amerika Singh, K. D. Srivastava, Rashmi Aggarwal, M. S. BeniwalAbstract:The application of Trichoderma viride on Loose Smut infected seeds ( Ustilago segetum var. tritici ) or in soil, reduced the Smutted tillers up to 17.5 per cent. However, treatment of T. viride alone was not as effective as carboxin seed treatment in the control of Loose Smut. Maximum reduction was observed in dry seed treatment with antagonist as well as seed treatment plus soil application. The effect of T. viride was more prominent in the seed lot having lower level of Loose Smut infection. Application of T. viride along with half dose of carboxin was however. found as effective as full recommended dose of carboxin (2.5 g/kg of seed). Soaking of seeds in tap water for 24h also reduced tbe incidence of Loose Smut by 15.4 per cent.
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possible biocontrol of Loose Smut of wheat ustilago segetum var tritici
Journal of Biological Control, 1992Co-Authors: Rashmi Agarwal, S NagarajanAbstract:Loose Smut of wheat ( Triticum aestivum Lin.) caused by Ustilago segetum var. tritici is a major disease in north-western India. Loss caused by the disease varies from about 1 to 10 per cent (Joshi et al., 1985). The popular high yielding cultivars are genetically susceptible to the disease and treatment with systemic fungicides is the only means of disease control. Biological control of soil-borne diseases using toxin or antibiotic producing strains and those that are mycophagous have opened up potential areas for research (Cook, 1984). Therefore, an experiment was laid out using microbial antagonists to control the Loose Smut.
G J Scoles - One of the best experts on this subject based on the ideXlab platform.
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fine mapping and identification of a candidate gene for the barley un8 true Loose Smut resistance gene
Theoretical and Applied Genetics, 2015Co-Authors: Wen Zang, P E Eckstein, D Voth, G J Scoles, Mark Colin, Axel Himmelbach, Sebastian Beier, Nils Stein, Aaron D BeattieAbstract:The candidate gene for the barley Un8 true Loose Smut resistance gene encodes a deduced protein containing two tandem protein kinase domains. In North America, durable resistance against all known isolates of barley true Loose Smut, caused by the basidiomycete pathogen Ustilago nuda (Jens.) Rostr. (U. nuda), is under the control of the Un8 resistance gene. Previous genetic studies mapped Un8 to the long arm of chromosome 5 (1HL). Here, a population of 4625 lines segregating for Un8 was used to delimit the Un8 gene to a 0.108 cM interval on chromosome arm 1HL, and assign it to fingerprinted contig 546 of the barley physical map. The minimal tilling path was identified for the Un8 locus using two flanking markers and consisted of two overlapping bacterial artificial chromosomes. One gene located close to a marker co-segregating with Un8 showed high sequence identity to a disease resistance gene containing two kinase domains. Sequence of the candidate gene from the parents of the segregating population, and in an additional 19 barley lines representing a broader spectrum of diversity, showed there was no intron in alleles present in either resistant or susceptible lines, and fifteen amino acid variations unique to the deduced protein sequence in resistant lines differentiated it from the deduced protein sequences in susceptible lines. Some of these variations were present within putative functional domains which may cause a loss of function in the deduced protein sequences within susceptible lines.
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development of pcr based markers for a gene un8 conferring true Loose Smut resistance in barley
Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie, 2002Co-Authors: P E Eckstein, N Krasichynska, D Voth, S Duncan, B G Rossnagel, G J ScolesAbstract:Breeding for true Loose Smut (Ustilago nuda (Jens.) Rostr.) resistance in barley is expensive because of the great requirements for time, labour, and growth space, and thus is an ideal candidate for screening by indirect methods. One gene (Un8) confers resistance to most known races of the true Loose Smut pathogen and is the gene present in the majority of western Canadian barley cultivars. Here we report on linkage between this gene and a restriction fragment length polymorphism marker, or various forms of the marker, in a number of segregating barley populations. The different forms of the marker were developed through sequencing and postamplification restriction. The resulting allele-specific amplicon markers can be used in a relatively simple assay, based on the polymerase chain reaction, specific for either the resistant or susceptible allele. The marker was linked to the resistance gene in five crosses involving two sources of resistance and was located on chromosome 5 (1HL). The allele-specific amp...
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Targeted development of a microsatellite marker associated with a true Loose Smut resistance gene in barley (Hordeum vulgare L.)
Molecular Breeding, 2001Co-Authors: Cheng-dao Li, P E Eckstein, B G Rossnagel, Minyan Lu, G J ScolesAbstract:Microsatellite markers have many of the properties of an ideal marker, but development of microsatellite markers is tedious, time-consuming and expensive. In the past few years, great efforts have been made to develop, map and utilize microsatellite markers in various crops. It is still a major challenge to find a microsatellite marker associated with an economically important trait. In the present study we report on the targeted development of a microsatellite marker to a barley disease resistance gene. The method includes the following steps: (1) pooling DNA samples from a segregating population based on the principle of bulked-segregant analysis; (2) digesting the pooled DNAs and ligating adaptors; (3) selectively amplifying and identifying polymorphic microsatellites; and (4) developing primers for the microsatellite associated with the targeted trait. Using this method, a microsatellite marker associated with the true Loose Smut resistance gene ( Un8 ) in the Harrington × TR306 doubled-haploid population was identified. This marker showed polymorphism in four breeding populations segregating for true Loose Smut resistance. In three of these populations, genetic distance between the microsatellite and the true Loose Smut resistance gene varied from 8.6 to 10.3 cM. Polymorphism of the microsatellite was tested among three disease resistant lines and 21 susceptible cultivars. Fourteen to eighteen of the 21 susceptible cultivars exhibited a polymorphism for the microsatellite with respect to at least one of the disease-resistant lines. This method for the targeted development of microsatellite markers should have widespread applicability and should efficiently provide highly polymorphic markers for use in breeding programs.
Rashmi Agarwal - One of the best experts on this subject based on the ideXlab platform.
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possible biocontrol of Loose Smut of wheat ustilago segetum var tritici
Journal of Biological Control, 1992Co-Authors: Rashmi Agarwal, S NagarajanAbstract:Loose Smut of wheat ( Triticum aestivum Lin.) caused by Ustilago segetum var. tritici is a major disease in north-western India. Loss caused by the disease varies from about 1 to 10 per cent (Joshi et al., 1985). The popular high yielding cultivars are genetically susceptible to the disease and treatment with systemic fungicides is the only means of disease control. Biological control of soil-borne diseases using toxin or antibiotic producing strains and those that are mycophagous have opened up potential areas for research (Cook, 1984). Therefore, an experiment was laid out using microbial antagonists to control the Loose Smut.
P E Eckstein - One of the best experts on this subject based on the ideXlab platform.
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fine mapping and identification of a candidate gene for the barley un8 true Loose Smut resistance gene
Theoretical and Applied Genetics, 2015Co-Authors: Wen Zang, P E Eckstein, D Voth, G J Scoles, Mark Colin, Axel Himmelbach, Sebastian Beier, Nils Stein, Aaron D BeattieAbstract:The candidate gene for the barley Un8 true Loose Smut resistance gene encodes a deduced protein containing two tandem protein kinase domains. In North America, durable resistance against all known isolates of barley true Loose Smut, caused by the basidiomycete pathogen Ustilago nuda (Jens.) Rostr. (U. nuda), is under the control of the Un8 resistance gene. Previous genetic studies mapped Un8 to the long arm of chromosome 5 (1HL). Here, a population of 4625 lines segregating for Un8 was used to delimit the Un8 gene to a 0.108 cM interval on chromosome arm 1HL, and assign it to fingerprinted contig 546 of the barley physical map. The minimal tilling path was identified for the Un8 locus using two flanking markers and consisted of two overlapping bacterial artificial chromosomes. One gene located close to a marker co-segregating with Un8 showed high sequence identity to a disease resistance gene containing two kinase domains. Sequence of the candidate gene from the parents of the segregating population, and in an additional 19 barley lines representing a broader spectrum of diversity, showed there was no intron in alleles present in either resistant or susceptible lines, and fifteen amino acid variations unique to the deduced protein sequence in resistant lines differentiated it from the deduced protein sequences in susceptible lines. Some of these variations were present within putative functional domains which may cause a loss of function in the deduced protein sequences within susceptible lines.
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development of pcr based markers for a gene un8 conferring true Loose Smut resistance in barley
Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie, 2002Co-Authors: P E Eckstein, N Krasichynska, D Voth, S Duncan, B G Rossnagel, G J ScolesAbstract:Breeding for true Loose Smut (Ustilago nuda (Jens.) Rostr.) resistance in barley is expensive because of the great requirements for time, labour, and growth space, and thus is an ideal candidate for screening by indirect methods. One gene (Un8) confers resistance to most known races of the true Loose Smut pathogen and is the gene present in the majority of western Canadian barley cultivars. Here we report on linkage between this gene and a restriction fragment length polymorphism marker, or various forms of the marker, in a number of segregating barley populations. The different forms of the marker were developed through sequencing and postamplification restriction. The resulting allele-specific amplicon markers can be used in a relatively simple assay, based on the polymerase chain reaction, specific for either the resistant or susceptible allele. The marker was linked to the resistance gene in five crosses involving two sources of resistance and was located on chromosome 5 (1HL). The allele-specific amp...
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Targeted development of a microsatellite marker associated with a true Loose Smut resistance gene in barley (Hordeum vulgare L.)
Molecular Breeding, 2001Co-Authors: Cheng-dao Li, P E Eckstein, B G Rossnagel, Minyan Lu, G J ScolesAbstract:Microsatellite markers have many of the properties of an ideal marker, but development of microsatellite markers is tedious, time-consuming and expensive. In the past few years, great efforts have been made to develop, map and utilize microsatellite markers in various crops. It is still a major challenge to find a microsatellite marker associated with an economically important trait. In the present study we report on the targeted development of a microsatellite marker to a barley disease resistance gene. The method includes the following steps: (1) pooling DNA samples from a segregating population based on the principle of bulked-segregant analysis; (2) digesting the pooled DNAs and ligating adaptors; (3) selectively amplifying and identifying polymorphic microsatellites; and (4) developing primers for the microsatellite associated with the targeted trait. Using this method, a microsatellite marker associated with the true Loose Smut resistance gene ( Un8 ) in the Harrington × TR306 doubled-haploid population was identified. This marker showed polymorphism in four breeding populations segregating for true Loose Smut resistance. In three of these populations, genetic distance between the microsatellite and the true Loose Smut resistance gene varied from 8.6 to 10.3 cM. Polymorphism of the microsatellite was tested among three disease resistant lines and 21 susceptible cultivars. Fourteen to eighteen of the 21 susceptible cultivars exhibited a polymorphism for the microsatellite with respect to at least one of the disease-resistant lines. This method for the targeted development of microsatellite markers should have widespread applicability and should efficiently provide highly polymorphic markers for use in breeding programs.
Ramesh Chand Sharma - One of the best experts on this subject based on the ideXlab platform.
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characterization of ustilago segetum tritici causing Loose Smut of wheat in northwestern india
Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie, 2014Co-Authors: Gurpreet Kaur, I Sharma, Ramesh Chand SharmaAbstract:AbstractLoose Smut of wheat, caused by Ustilago segetum tritici, occurs in India wherever the crop is grown. Chemical seed treatments used by seed producers and farmers result in a low incidence of the disease. However, the deployment of Loose Smut resistant cultivars could lead to reduced use of seed treatment chemicals in the wheat crop. Knowledge of the virulence of natural populations of U. segetum tritici is necessary to identify effective host genes for resistance. Since the late 1980s, there have been sporadic reports on the virulence characteristics of the U. segetum tritici population in India, but the current status is unknown. Thirty-five isolates of U. segetum tritici were collected from cultivars grown at various locations in five states of northwestern India from 2008–2011. The collected isolates were characterized for virulence on the standard Canadian differential set developed by Nielsen. The isolates represented 6 races, representing 43% of the 35 isolates, with race T34 being the most c...
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characterization of ustilago segetum causing Loose Smut of wheat
Journal of Wheat Research, 2011Co-Authors: Gurpreet Kaur, I Sharma, Ramesh Chand SharmaAbstract:Isolates of Loose Smut of wheat caused by Ustilago segetum (Pers.) Roussel tritici Jensen were collected from different cultivars of wheat grown at various locations of North-Western Indi (Punjab, Haryana, U.P. and Rajasthan). The genetic relationships of molecular variability and and virulence pattern among these races is unknown. In this study, a total of 24 isolates of representing six groups of U. segetum tritici were studied using molecular and virulence data. In total, eighteen random decamer primers and ISSR primers were used to characterize twenty four isolates of the pathogen. The RAPD and ISSR primers were used for polymorphism analysis and generated a total of 206 scorable bands collectively. All the isolates could be precisely differentiated from each other employing these primers and grouped into two distinct clusters. The classification at molecular level did not exactly collate with the geographical distribution of the isolates and virulence / pathogenicity.
