Location: Vegetable Crops Research
Project Number: 5090-21000-073-078-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2022
End Date: Aug 31, 2025
Objective:
1. Identification of genes and QTL for bacterial wilt (BW) resistance in cucumber in both biparental and natural populations.
2. Development of molecular tools for the genetic manipulation of the BW pathogen (Erwinia tracheiphila, Et) and identification of key pathogenesis players in Et that will interact with cucumber host.
3. Leveraging and strengthening existing research collaboration in the area of molecular plant-pathogen interactions between ARS and 1890 LGU labs.
Approach:
Objective 1. Identification of genes and QTL for BW resistance in cucumber
QTL mapping of BW resistance in WI2757 will be conducted with 120 recombinant inbred lines (RILs) from WI2757 × True Lemon. Disease resistance of these RILs will be evaluated with inoculation tests in the greenhouses. Disease index data will be used for QTL analysis to identify the resistance gene locus or QTL. The candidate gen region will be narrowed down with fine genetic mapping. Genome-wide association analysis of BW resistance will be conducted with 192 cucumber lines. Phenotypic data of these lines will be collected in greenhouse trials. Genotypic data have already generated by ARS will be used in this project. GWAS analysis will be conducted with TASSEL 5.0. This part of work will be performed in the second year of cooperator’s sabbatical leave.
Objective 2. Molecular tool development and pathogen genetic manipulation
The cooperator will construct a series of molecular tools for the genetic analysis of Et and other pathogenic bacteria. New Et pathogen mutants will be developed through transposon tagging. Modified transposons will be used to construct saturated mutant libraries of Et strains from melon and squash. Mutant will be identified with various approaches focusing on identification of mutant genes involved in host interaction in BW.
