New Classification Method for Plasmodiophora brassicae Field Isolates in Japan Based on Resistane of F1 Cultivars of Chinese Cabbage (Brassica rapa L.) to Clubroot

Hatakeyama, Katsunori; Fujimura, Miyuki; Ishida, Masahiko; Suzuki, Tohru

doi:10.1270/jsbbs.54.197

Cited by 40 publications

(42 citation statements)

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“…To elucidate differentiation of the virulence, two kinds of differential host set were released and extensively used to identify pathogen races (Williams 1966, Buczacki et al 1975, Crute et al 1980. However, some of the hosts showed intermediate responses to pathogen isolates, and this makes clear racial identification difficult (Yoshikawa 1993, Hatakeyama et al 2004. Since these hosts are open pollinated lines, it is possible to induce changes in gene frequencies of the host lines during amplification of the seed stock.…”

Section: Genetic Variation In Virulence Of the Pathogen Isolatesmentioning

confidence: 99%

Genetic Analysis of Clubroot Resistance in Brassica Crops

Hirai

2006

Breed. Sci.

109

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Clubroot disease is caused by an obligate parasite, Plasmodiophora brassicae, and is one of the most serious diseases of Brassica crops worldwide. The pathogen is a eukaryote, and is a member of Plasmodiophorales. Recent phylogenic studies did not reveal its close relationship to fungi, but suggest a classification in Protozoa or Protoctista. The infection is thought to occur through two phases. The pathogen induces massive clubs on root, and prevents host growth. A number of clubroot resistance (CR) Chinese cabbage (Brassica rapa) cultivars have been bred using European turnips as sources of CR genes. Field populations of the pathogen have a wide variation of virulence, which causes the infection of CR Chinese cabbage cultivars. The CR gene of B. rapa is extensively studied with the aid of molecular markers. At least four independent loci are identified and mapped. They are all derived from European turnips. Crr1, and Crr2 are derived from Siloga and mapped in linkage groups R8 and R6, respectively. Crr3 from Milan White, and CRb from Gelria R are both mapped in R3. The molecular markers linked to Crr1, Crr2 and CRb showed homology to the central part of the long arm of chromosome 4 of Arabidopsis thaliana. These findings suggest that these CR genes are derived from the same region of the ancestral genome. In contrast, Crr3 is thought to have different origin, since its linkage markers showed homology to chromosome 3 of A. thaliana. Although another CR gene CRa is reported, the relationship between above mentioned four CR loci and CRa is not yet clarified. Genetic studies on CR genes in B. oleracea revealed a polygenic nature of the trait in this species and also suggest the presence of one CR gene having large effect. However, correspondence among the CR genes reported in these studies is not clarified because of the lack of information on base sequence of the linkage markers in this species. Strategies for breeding of more resistant Chinese cabbage cultivars to overcome the variation on virulence of field populations of the pathogen are presented.

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Section: Genetic Variation In Virulence Of the Pathogen Isolatesmentioning

confidence: 99%

Genetic Analysis of Clubroot Resistance in Brassica Crops

Hirai

2006

Breed. Sci.

109

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“…isolates collected from Nagano prefecture (data not shown). Two F 1 cultivars 'Ryutoku' and 'Super CR Hiroki', which are recognized as differential hosts for classifying P. brassicae isolates (Hatakeyama et al 2004), formed clubs, regardless of the extent, in all the isolates except M85. M85 had slight pathogenicity against 'Ryutoku'.…”

Section: Resultsmentioning

confidence: 99%

“…These turnips possibly have plural CR genes and show high resistance to various pathotypes, whereas resistance of derivative Chinese cabbage accessions is restricted, probably because of a partial loss of CR genes in the breeding process (Kuginuki et al, 1999). CR cultivars, however, exhibit varied responses to the pathogens (Hatakeyama et al, 2004). They are assumed to be diverse in genetic background, but insufficient for the accumulation of resistance genes to overcome the pathogen.…”

Section: Discussionmentioning

confidence: 99%

“…Various classification methods of clubroot isolates have been established using different indicator plants (Buczacki et al, 1975;Crute et al, 1980;Williams, 1966). Kuginuki et al (1999) and Hatakeyama et al (2004) proposed the classification system for P. brassicae using F 1 cultivars of Chinese cabbage as differential hosts. Six isolates used here had different virulence to each CR gene.…”

Section: Discussionmentioning

confidence: 99%

“…The isolates K04, NN34, and T223 could be categorized into group 1, which shows the highest pathogenicity, according to the classification method by Hatakeyama et al (2004); NH117 and T217 fall between groups 1 and 2, while M85 falls between groups 3 and 4. From the responses of 3 loci, it turned out that group 1 of Hatakeyama et al (2004) could be subdivided into 2 groups, and that intermediately grouped isolates could be classified more discretely, possibly because of the specific nature of resistance and homozygosity of each CR loci. These results suggest that the CR loci CRa, CRk, and CRc may be employed for fine classification of the clubroot pathogen.…”

Section: Discussionmentioning

confidence: 99%

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Accumulation of Three Clubroot Resistance Genes through Marker-assisted Selection in Chinese Cabbage (Brassica rapa ssp. pekinensis).

Matsumoto¹,

Ueno

Aruga

et al. 2012

J. Japan. Soc. Hort. Sci.

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Many clubroot resistant (CR) cultivars of Chinese cabbage (Brassica rapa ssp. pekinensis) have been bred so far, but their usage is limited because the capacity for resistance breaks down with time. This degradation is caused by a pathogenic variation in the causal fungus Plasmodiophora brassicae. We attempted to accumulate 3 CR genes, CRa, CRk, and CRc, through marker-assisted selection. Five doubled haploid CR lines with an individual CR locus were used as breeding materials. The CR lines were crossed with each other. A subsequent selection for resistance was performed using sequence characterized amplified region markers in segregating generations. As a result, 4 homozygous lines for 3 resistance genes and the F 1 hybrids between them were developed. CR pyramiding lines were inoculated with 6 field isolates of P. brassicae. The homozygous lines for 3 CR genes, whether selfed or crossed, exhibited exceedingly high resistance against all of the isolates. Morphological characters of F 1 hybrids were comparable to those of a control cultivar, but the degree of heterosis was less than expected, which is probably because of genetic similarity of the parents. The results of this study prove that clubroot resistance can be reinforced through the accumulation of varied resistance genes in B. rapa.

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