Genetic and molecular analysis reveals that two major loci and their interaction confer clubroot resistance in canola introgressed from rutabaga

Abstract

Clubroot disease caused by Plasmodiophora brassicae is one of the serious threats to canola (Brassica napus L. subsp. napus) production. The evolution of new pathotypes rendering available resistances ineffective compel the introgression of new resistance into canola and extend our understanding of the genetic and molecular basis of the resistance. In this paper, we report the genetic and molecular basis of clubroot resistance in canola, introgressed from a rutabaga (B. napus L. subsp. rapifera Metzg. ‘Polycross’), by using a doubled‐haploid (DH) mapping population. Whole‐genome resequencing (WGRS)‐based bulked segregant analysis followed by genetic mapping and expression analysis of the genes in resistant and susceptible DH lines at 7 and 14 d after inoculation were carried out. Following this approach, two major quantitative trait loci (QTL) located at 14.41–15.44 Mb of A03 and at 9.96–11.09 Mb of A08 chromosomes and their interaction was observed to confer resistance to pathotypes 3H, 3A, and 3D. Analysis of the genes from the two QTL regions suggested that decreased expression of sugar transporter genes (BnaA03g29290D and BnaA03g29310D) may play an important role in resistance conferred by the A03 QTL, while increased expression of the toll/interleukin‐1 receptor (TIR)–nucleotide binding (NB)–leucine rich repeat (LRR) (TNL) genes (BnaA08g10100D, BnaA08g09220D, and BnaA08g10540D) could be the major determinant of the resistance conferred by the A08 QTL. Single‐nucleotide polymorphism (SNP) allele‐specific polymerase chain reaction (PCR)‐based markers, which could be detected by agarose gel electrophoresis, were also developed from the two QTL regions for use in breeding including pyramiding of multiple clubroot resistance genes.

Advances in Biological Control and Resistance Genes of Brassicaceae Clubroot Disease-The Study Case of China

“…Jiang et al studied the CR locus found in resistant "Kc84R" and identified BnERF034 as one of the CR genes on chromosome A03 [115]. Indeed, many CR loci have been reported, including the ones recently identified by Wang et al, for two QTLs on A03 and A08, conferring resistance to pathotypes 3H, 3A, and 3D in turnip [116]. The development of markers and identification of genomic regions responsible for clubroot resistance laid an important foundation for marker-assisted breeding for the generation of resistant cultivars with durable resistance to clubroot disease.…”

RNA-Seq Bulked Segregant Analysis of an Exotic B. napus ssp. napobrassica (Rutabaga) F2 Population Reveals Novel QTLs for Breeding Clubroot-Resistant Canola

“…'Brookfield', which was resistant to all five 'old' pathotypes (2F, 3H, 5I, 6M, and 8N) found in Canada prior to the introduction of clubroot-resistant canola. Wang et al [35] used a rutabaga cv. 'Polycross' as a resistance donor to breed for canola populations resistant to three Canadian pathotypes.…”

Resynthesizing Brassica napus with race specific resistance genes and race non-specific QTLs to multiple races of Plasmodiophora brassicae

“…Recently, two major ( Rcr11 and Rcr13 ) and one minor QTL ( Rcr_C03-4 ECD10 ) were identified for resistance to 12 pathotypes (3A, 2B, 5C, 3D, 8E, 5G, 3H, 8J, 5L, 3O, 8P, and 5X) of Plasmodiophora brassicae in the B. napus cultivar ECD10 through genotyping-by-sequencing 18 . Identification of major genes conferring resistance to Canadian pathotypes in Brassica species has been also conducted at the University of Manitoba 19 , 20 and the University of Alberta 21 – 27 . However, these major genes typically provide qualitative resistance, which is considered race-specific and can be rapidly overcome by the pathogen.…”