9:30 am - 10:30 am
A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Zhengping Wang. This seminar is open to the general public to attend.
Meeting ID: 965 7106 4536 | Passcode: 473850
Thesis Topic: Genetic and molecular analysis of clubroot resistance in canola introgressed from rutabaga cvs. Polycross and Brookfield
MSc with Drs. Nat Kav and Habib Rahman.
Clubroot disease caused by Plasmodiophora brassicae is one of the serious threats to canola (Brassica napus) production. The evolution of new pathotypes rendering available resistances ineffective, which compels the introgression of new resistance into canola and extension our understanding of the genetic and molecular basis of the resistance. The clubroot resistance from rutabaga (B. napus var. napobrassica) cvs. Polycross and Brookfield have been introgressed into canola in previous study.
In the first study of this thesis, I report the genetic and molecular basis of clubroot resistance in canola, introgressed from a rutabaga cv. Polycross, by using a doubled haploid (DH) population. Whole genome resequencing-based bulked segregant analysis followed by genetic mapping was carried out to identify the genomic regions contributing to this resistance, and expression analysis of the genes from the quantitative trait loci (QTL) regions was carried out to understand the molecular basis of this resistance. Following this approach, two major QTL located at 14.41-15.44 Mb of A03 and at 9.96-11.09 Mb of A08 chromosomes and their interaction was found to confer resistance to pathotypes 3H, 3A and 3D P. brassicae. Analysis of the genes from these two QTL regions suggested that decreased expression of sugar transporter genes may play an important role in resistance conferred by the A03 QTL, while increased expression of the TNL genes could be the major determinant of the resistance conferred by the A08 QTL. SNP allele-specific PCR-based markers, which could be detected by agarose gel electrophoresis, were also developed from these two QTL for use in breeding including pyramiding of multiple clubroot resistance genes. In the second study of this thesis, I investigated four putative clubroot resistance genes and long noncoding RNAs (lncRNAs) from primary and secondary metabolic pathways through overexpression in Arabidopsis thaliana; these genes and lncRNAs were identified through transcriptome analysis of B. napus lines carrying clubroot resistance of the rutabaga cv. Brookfield. However, none of the homozygous transgenic A. thaliana lines carrying the above-mentioned genes or lncRNAs showed resistance to clubroot disease. It indicates these genes and lncRNAs might not be directly involved in clubroot resistance.
Thus, the knowledge and materials generated from this thesis research can be used in breeding canola for durable resistance clubroot disease.