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Reassessment of QTLs for late blight resistance in the tomato accession L3708 using a restriction site associated DNA (RAD) linkage map and highly aggressive isolates of Phytophthora infestans.

Chen AL, Liu CY, Chen CH, Wang JF, Liao YC, Chang CH, Tsai MH, Hwu KK, Chen KY - PLoS ONE (2014)

Bottom Line: The RAD-seq data were used to construct a genetic linkage map containing 440 single nucleotide polymorphism markers.Quantitative trait locus (QTL) analysis identified a new disease-resistant QTL specific to Pi733 on chromosome 2.The Ph-3 gene located on chromosome 9 could be detected whichever isolates were used.

View Article: PubMed Central - PubMed

Affiliation: Department of Agronomy, National Taiwan University, Taipei, Taiwan.

ABSTRACT
Tomato late blight caused by the oomycete pathogen Phytophthora infestans (Mont.) de Bary is a major threat to tomato production in cool and wet environments. Intensified outbreaks of late blight have been observed globally from the 1980s, and are associated with migration of new and more aggressive populations of P. infestans in the field. The objective of this study was to reassess late blight resistance in the wild tomato accession L3708 (Solanum pimpinellifolium L.) against pathogens of different aggressiveness. An F2:3 genetic mapping population was developed using L3708 as the paternal parent. Two isolates of P. infestans, Pi39A and Pi733, were used for inoculation. Pi733 is a highly aggressive genotype that defeats three known late blight resistance genes, Ph-1, Ph-2, and Ph-5t in tomato. In contrast, Pi39A is a less aggressive genotype that defeats only Ph-1. Restriction site Associated DNA Sequencing (RAD-Seq) technology was used to massively sequence 90 bp nucleotides adjacent to both sides of PstI restriction enzyme cutting sites in the genome for all individuals in the genetic mapping population. The RAD-seq data were used to construct a genetic linkage map containing 440 single nucleotide polymorphism markers. Quantitative trait locus (QTL) analysis identified a new disease-resistant QTL specific to Pi733 on chromosome 2. The Ph-3 gene located on chromosome 9 could be detected whichever isolates were used. This study demonstrated the feasibility and efficiency of RAD-Seq technology for conducting a QTL mapping experiment using an F2:3 mapping population, which allowed the identification of a new late blight resistant QTL in tomato.

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Related in: MedlinePlus

Disease severity rating (DSR) for isolates Pi39A and Pi733.(A) Distribution of DSR in the mapping population. (B) Relationship of the two DSR score sets generated from independent inoculations of Pi39A and Pi733.
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pone-0096417-g001: Disease severity rating (DSR) for isolates Pi39A and Pi733.(A) Distribution of DSR in the mapping population. (B) Relationship of the two DSR score sets generated from independent inoculations of Pi39A and Pi733.

Mentions: To identify resistance QTLs to different P. infestans isolates, an F2:3 genetic mapping population was developed from a cross of resistant S. pimpinellifolium accession L3708 and susceptible cultivated tomato S. lycopersicum. One hundred and twenty F2:3 lines were randomly selected for phenotypic evaluation. Seedlings grown from the 120 F2:3 lines were inoculated separately with either Pi39A or Pi733 isolates. Disease severity ratings for each inoculation were scored at the time that the susceptible tomato cultivar M82 control reached maximum severity. The DSR scores for resistant parent L3708 were 0.112 and 0.144, for Pi39A and Pi733, respectively. The DSR scores of the 120 F2:3 lines against Pi39A ranged from 0.109 to 4.984, with a mean of 1.537, and skewed towards zero (Figure 1A; Table S4). In contrast, DSR scores of the 120 F2:3 lines against Pi733 ranged from 0.346 to 5.921, with a mean of 3.149, and showed an approximate equal frequency among the different DSR classes (Figure 1A; Table S4). These results implied that the Pi733 isolate was more aggressive than the Pi39A isolate. The correlation coefficient between the DSR scores when inoculating Pi39A and Pi733 was 0.704 (Figure 1B), which implied that common genes conferred resistance against both isolates.


Reassessment of QTLs for late blight resistance in the tomato accession L3708 using a restriction site associated DNA (RAD) linkage map and highly aggressive isolates of Phytophthora infestans.

Chen AL, Liu CY, Chen CH, Wang JF, Liao YC, Chang CH, Tsai MH, Hwu KK, Chen KY - PLoS ONE (2014)

Disease severity rating (DSR) for isolates Pi39A and Pi733.(A) Distribution of DSR in the mapping population. (B) Relationship of the two DSR score sets generated from independent inoculations of Pi39A and Pi733.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4008630&req=5

pone-0096417-g001: Disease severity rating (DSR) for isolates Pi39A and Pi733.(A) Distribution of DSR in the mapping population. (B) Relationship of the two DSR score sets generated from independent inoculations of Pi39A and Pi733.
Mentions: To identify resistance QTLs to different P. infestans isolates, an F2:3 genetic mapping population was developed from a cross of resistant S. pimpinellifolium accession L3708 and susceptible cultivated tomato S. lycopersicum. One hundred and twenty F2:3 lines were randomly selected for phenotypic evaluation. Seedlings grown from the 120 F2:3 lines were inoculated separately with either Pi39A or Pi733 isolates. Disease severity ratings for each inoculation were scored at the time that the susceptible tomato cultivar M82 control reached maximum severity. The DSR scores for resistant parent L3708 were 0.112 and 0.144, for Pi39A and Pi733, respectively. The DSR scores of the 120 F2:3 lines against Pi39A ranged from 0.109 to 4.984, with a mean of 1.537, and skewed towards zero (Figure 1A; Table S4). In contrast, DSR scores of the 120 F2:3 lines against Pi733 ranged from 0.346 to 5.921, with a mean of 3.149, and showed an approximate equal frequency among the different DSR classes (Figure 1A; Table S4). These results implied that the Pi733 isolate was more aggressive than the Pi39A isolate. The correlation coefficient between the DSR scores when inoculating Pi39A and Pi733 was 0.704 (Figure 1B), which implied that common genes conferred resistance against both isolates.

Bottom Line: The RAD-seq data were used to construct a genetic linkage map containing 440 single nucleotide polymorphism markers.Quantitative trait locus (QTL) analysis identified a new disease-resistant QTL specific to Pi733 on chromosome 2.The Ph-3 gene located on chromosome 9 could be detected whichever isolates were used.

View Article: PubMed Central - PubMed

Affiliation: Department of Agronomy, National Taiwan University, Taipei, Taiwan.

ABSTRACT
Tomato late blight caused by the oomycete pathogen Phytophthora infestans (Mont.) de Bary is a major threat to tomato production in cool and wet environments. Intensified outbreaks of late blight have been observed globally from the 1980s, and are associated with migration of new and more aggressive populations of P. infestans in the field. The objective of this study was to reassess late blight resistance in the wild tomato accession L3708 (Solanum pimpinellifolium L.) against pathogens of different aggressiveness. An F2:3 genetic mapping population was developed using L3708 as the paternal parent. Two isolates of P. infestans, Pi39A and Pi733, were used for inoculation. Pi733 is a highly aggressive genotype that defeats three known late blight resistance genes, Ph-1, Ph-2, and Ph-5t in tomato. In contrast, Pi39A is a less aggressive genotype that defeats only Ph-1. Restriction site Associated DNA Sequencing (RAD-Seq) technology was used to massively sequence 90 bp nucleotides adjacent to both sides of PstI restriction enzyme cutting sites in the genome for all individuals in the genetic mapping population. The RAD-seq data were used to construct a genetic linkage map containing 440 single nucleotide polymorphism markers. Quantitative trait locus (QTL) analysis identified a new disease-resistant QTL specific to Pi733 on chromosome 2. The Ph-3 gene located on chromosome 9 could be detected whichever isolates were used. This study demonstrated the feasibility and efficiency of RAD-Seq technology for conducting a QTL mapping experiment using an F2:3 mapping population, which allowed the identification of a new late blight resistant QTL in tomato.

Show MeSH
Related in: MedlinePlus