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.
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.
Department of Agronomy, National Taiwan University, Taipei, Taiwan.
Ai-Lin
AL
Chen
Department of Agronomy, National Taiwan University, Taipei, Taiwan.
Chu-Yin
CY
Liu
AVRDC - The World Vegetable Center, Shanhua, Tainan, Taiwan.
Chien-Hua
CH
Chen
AVRDC - The World Vegetable Center, Shanhua, Tainan, Taiwan.
Jaw-Fen
JF
Wang
Known-You Seed Co. LTD., Kaohsiung, Taiwan.
Yu-Chen
YC
Liao
Known-You Seed Co. LTD., Kaohsiung, Taiwan.
Chia-Hui
CH
Chang
Institute of Biotechnology, National Taiwan University, Taipei, Taiwan; Center for Biotechnology, National Taiwan University, Taipei, Taiwan.
Mong-Hsun
MH
Tsai
Department of Agronomy, National Taiwan University, Taipei, Taiwan.
Kae-Kang
KK
Hwu
Department of Agronomy, National Taiwan University, Taipei, Taiwan.
Kai-Yi
KY
Chen
D002874:Chromosome Mapping / Q000379:methods*; D032461:Chromosomes, Plant / Q000235:genetics; D060467:Disease Resistance / Q000235:genetics*; D017343:Genes, Plant / Q000235:genetics; D005838:Genotype; D054884:Host-Pathogen Interactions / Q000235:genetics; D055750:Phytophthora infestans / Q000145:classification / Q000235:genetics* / Q000502:physiology; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D020641:Polymorphism, Single Nucleotide; D040641:Quantitative Trait Loci / Q000235:genetics*; D017422:Sequence Analysis, DNA / Q000379:methods; D032322:Solanum / Q000235:genetics* / Q000382:microbiology; D013045:Species Specificity