Tomato mosaic virus(ToMV)drastically affects the tomato production worldwide.To deal with this problem,breeding of ToMV-resistant hybrids/varieties is the ultimate need and most successful approach.In wild tomato spec...Tomato mosaic virus(ToMV)drastically affects the tomato production worldwide.To deal with this problem,breeding of ToMV-resistant hybrids/varieties is the ultimate need and most successful approach.In wild tomato species,three dominant ToMV-resistant genes(Tm-1,Tm-2 and Tm-2^(2))were identified and the World Vegetable Center developed few fresh market tomato lines resistant to ToMV by the introgression of these genes.Recently at Nuclear Institute for Agriculture and Biology,Faisalabad,Pakistan a breeding programme was initiated to develop high yielding and ToMV tolerant hybrids using these lines.Current study was performed to screen elite F1 hybrids carrying Tm gene along with their parents against ToMV using mechanical inoculation,confirmation of the virus using DAS-ELISA and marker assisted selection of hybrids.Out of 28 hybrids and 17 parent accessions/genotypes,eight hybrids and five accessions were found to be highly resistant and the virus was not detected in DAS-ELISA.Five hybrids were resistant,nine hybrids and four genotypes were tolerant,while the remaining six hybrids and eight genotypes were susceptible.For the confirmation of Tm-2^(2) gene,the tomato hybrids and their parents were subjected to molecular analysis using cleaved amplified polymorphic sequence(CAPS)primers.The result of CAPS markers for the confirmation of Tm-2^(2) gene was found consistent with phenotypic data of the inoculated tomato genotypes/hybrids.Higher phenolic content,total soluble proteins,better CAT and SOD activities were positively correlated with resistance.Screening results based on phenotype,biochemical and molecular marker data indicate that hybrids carrying Tm-2^(2) gene are good sources of resistance against ToMV.展开更多
Tomato mosaic virus (ToMV) is one of the most infectious virus diseases in tomato (Solanum lycopersicum L). The practical and effective method of controlling this disease is through genetic control by using major resi...Tomato mosaic virus (ToMV) is one of the most infectious virus diseases in tomato (Solanum lycopersicum L). The practical and effective method of controlling this disease is through genetic control by using major resistance genes. So far, three genes Tm-1, Tm-2 and Tm-22 conferring resistance to ToMV have been reported and utilized in tomato culti-var development. Marker assisted selection (MAS) has become very important and useful tool in selection of ToMV re-sistant tomato lines or hybrids. The objective of this research was to identify allele-specific PCR-based, cleaved ampli-fied polymorphic sequence (CAPS), and allele-derived single nucleotide polymorphism (SNP) markers for Tm-2 loci. Four allele-specific PCR-based markers were identified: one for Tm-2, one for Tm-22, and two for the susceptible allele tm-2. Three allele-derived CAPS markers were identified, which can identify and distinguish three alleles, tm-2, Tm-2 and Tm-22 in tomato germplasm. Three SNP markers were developed specific for Tm-2 locus. These markers will pro-vide breeders with a tool in selection of Tm-2 and Tm-22 resistance genes in tomato breeding program.展开更多
文摘Tomato mosaic virus(ToMV)drastically affects the tomato production worldwide.To deal with this problem,breeding of ToMV-resistant hybrids/varieties is the ultimate need and most successful approach.In wild tomato species,three dominant ToMV-resistant genes(Tm-1,Tm-2 and Tm-2^(2))were identified and the World Vegetable Center developed few fresh market tomato lines resistant to ToMV by the introgression of these genes.Recently at Nuclear Institute for Agriculture and Biology,Faisalabad,Pakistan a breeding programme was initiated to develop high yielding and ToMV tolerant hybrids using these lines.Current study was performed to screen elite F1 hybrids carrying Tm gene along with their parents against ToMV using mechanical inoculation,confirmation of the virus using DAS-ELISA and marker assisted selection of hybrids.Out of 28 hybrids and 17 parent accessions/genotypes,eight hybrids and five accessions were found to be highly resistant and the virus was not detected in DAS-ELISA.Five hybrids were resistant,nine hybrids and four genotypes were tolerant,while the remaining six hybrids and eight genotypes were susceptible.For the confirmation of Tm-2^(2) gene,the tomato hybrids and their parents were subjected to molecular analysis using cleaved amplified polymorphic sequence(CAPS)primers.The result of CAPS markers for the confirmation of Tm-2^(2) gene was found consistent with phenotypic data of the inoculated tomato genotypes/hybrids.Higher phenolic content,total soluble proteins,better CAT and SOD activities were positively correlated with resistance.Screening results based on phenotype,biochemical and molecular marker data indicate that hybrids carrying Tm-2^(2) gene are good sources of resistance against ToMV.
文摘Tomato mosaic virus (ToMV) is one of the most infectious virus diseases in tomato (Solanum lycopersicum L). The practical and effective method of controlling this disease is through genetic control by using major resistance genes. So far, three genes Tm-1, Tm-2 and Tm-22 conferring resistance to ToMV have been reported and utilized in tomato culti-var development. Marker assisted selection (MAS) has become very important and useful tool in selection of ToMV re-sistant tomato lines or hybrids. The objective of this research was to identify allele-specific PCR-based, cleaved ampli-fied polymorphic sequence (CAPS), and allele-derived single nucleotide polymorphism (SNP) markers for Tm-2 loci. Four allele-specific PCR-based markers were identified: one for Tm-2, one for Tm-22, and two for the susceptible allele tm-2. Three allele-derived CAPS markers were identified, which can identify and distinguish three alleles, tm-2, Tm-2 and Tm-22 in tomato germplasm. Three SNP markers were developed specific for Tm-2 locus. These markers will pro-vide breeders with a tool in selection of Tm-2 and Tm-22 resistance genes in tomato breeding program.
