Digging out the unknown: Finding the resistance against verticillium stripe in canola

Term: 3 years, beginning in 2023
Status: Ongoing
Researcher(s): Dilantha Fernando, U of M
SaskCanola Investment: $82,957
Total Project Cost: $346,610
Funding Partners: ACPC, MCGA, WGRF

Objectives

The main objective of this project is to use genome-wide association studies to identify resistance in B. napus against the Verticillium longisporum pathogen, which will directly provide resistance sources for breeding programs in the control of verticillium stripe disease. Specifically, the objectives of the project are listed below:

1) Verticillium stripe disease evaluation in an approximate 250 to 500 Brassica napus genotypes and related species including Chinese and Canadian germplasm, and commercial canola varieties through plot trials in three growing seasons in two locations. Thus, the B. napus genotypes with high, moderate, and lower susceptibility against V. longisporum will be screened.

2) Genetic variation, population structure, and kinship coefficient analysis of the B. napus panel analysis. This will provide the genetic basis for the utilization of these B. napus genotypes in the potential breeding program. The genotype data can be extended for investigation of other agronomic important traits (yield, oil content, etc.) in canola.

3) Through the incorporation of the genotype and disease evaluation data, genome-wide association studies will be applied to identify the resistance loci, single nucleotide polymorphism (SNP), and resistance gene analogs (RGA) against V. longisporum in B. napus.

4) Identification of the candidate resistance genes/loci or quantitative trait loci determining the resistance to verticillium stripe disease through fine mapping and GWAS.

5) Developing SNP markers that are tightly linked to the verticillium stripe resistance loci, genes, or RGAs. The DNA marker can be used to quickly identify the new resistance source in canola varieties/genotypes for the breeding program.

Project Description

We expect our project to benefit the whole seed industry, growers, and the canola trade organizations, and an immense economic contribution to the Canadian economy (yearly revenues).

1) Through field trials, we can evaluate the resistant B. napus varieties/lines/ to Verticillium stripe disease. The screened resistance B. napus genotypes can be adopted to disease breeding programs directly. In addition, the susceptibilities against Verticillium longisporum pathogen in included commercial canola varieties will be reported to the industry. Proper labeling of resistance to Verticillium stripe disease can be introduced in the frequently used canola varieties.

2) Through genome-wide association studies and genetic mapping, the candidates of resistance genes/loci will be identified for further application and introgression of the resistance in disease breeding.

3) Through SNP marker development, it will be introduced to identify resistance quickly in Brassica species and facilitate marker-assisted selection.

4) The genotype data and B. napus genotypes from this panel will also be used for other key genes/loci identification related to other agronomic-important traits.

We collaborated with Dr. Fengqun Yu from AAFC-Saskatoon and worked on novel resistance gene identification against blackleg pathogen through genome-wide association studies under the support of the CARP program (2018-2021). This strategy proved to be an effective way to identify resistance loci/genes against fungal pathogens in Brassica napus. In our ongoing project CAP-Activity 34, we are evaluating the Verticillium stripe disease resistance in some Chinese B. napus genotypes, breeding/commercial lines in the fields having natural inoculum. Thus, we propose to expand our study to a wide range of B. napus genotypes including more Chinese genotypes, U of Manitoba breeding lines from Dr. Rob Duncan's group, commercial varieties (Bayer, Cargill, Nutrient, DLSeed, etc.), introgression lines from AAFC and use genome-wide association study to identify the resistance genes/sources against V. longisporum pathogen. Specifically, we will try to: 1) evaluate the Verticillium stripe disease resistance in a large B. napus genotypes collection through field plot trials and label the high, moderate, and low ‘resistance’; 2) understand the population diversity, structure, phylogenetic relations of the panel; 3) identify the resistance loci/genes through GWAS; 4) produce the genetic population for fine mapping the candidate genes; 5) develop and release KASP marker to the seed industry, growers, researchers for the marker-assisted breeding program.