Genetic characterization and mapping of late blight resistance genes in the wild tomato accession PI 270443
Open Access
- Author:
- Jia, Mengyuan
- Graduate Program:
- Plant Biology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- September 25, 2019
- Committee Members:
- Majid R Foolad, Dissertation Advisor/Co-Advisor
Majid R Foolad, Committee Chair/Co-Chair
Mark Guiltinan, Committee Member
Surinder Chopra, Committee Member
Beth Krueger Gugino, Outside Member
Hamid Ashrafi, Special Member
Teh-Hui Kao, Program Head/Chair - Keywords:
- Late blight
tomato
gene mapping
disease resistance
Recombinant Inbred Line
GBS
RNA-sequencing - Abstract:
- Late blight (LB), caused by oomycete Phytophthora infestans, is one of the most devastating diseases of the cultivated tomato (Solanum lycopersicum L.) worldwide. Wild tomato species are vital genetic resources for tomato breeding for many disease resistance and abiotic stress tolerance traits. Recently, we reported an accession (PI 270443) of the wild tomato species Solanum pimpinellifolium L. with LB resistance stronger than most commercially available LB-resistant tomato cultivars. This thesis study aimed to identify, map and characterize quantitative trait loci (QTLs) for LB resistance in PI 270443 using a new recombinant inbred line (RIL) population (F9 and F10 generations) of tomato, derived from a cross between this accession and an LB-susceptible tomato breeding line. A high-density genetic linkage map with 8,470 SNPs (1,195 bin markers) was constructed using the genotyping-by-sequencing (GBS) approach. High-resolution QTL analyses identified a major LB-resistance QTL on chromosome 10 explaining >50% of the phenotypic variation, and minor QTLs on chromosome 1 and 12 of PI 270443. Transcriptomic studies comparing the LB-resistant PI 270443 and susceptible parent under LB inoculation conditions identified candidate genes differentially expressed in the major QTL region on chromosome 10, including but not limited to, serine/threonine receptor kinase, receptor-like kinase and ubiquitin conjugating enzyme 2, facilitating discovery of novel LB -resistant gene(s).