Race specific resistance against Phytophthora infestans in potato is controlled by more genetic factors than only R-genes

Euphytica ◽  
1996 ◽  
Vol 90 (3) ◽  
pp. 331-336 ◽  
Author(s):  
Ali El-Kharbotly ◽  
Andy Pereira ◽  
Willem J. Stiekema ◽  
Evert Jacobsen
Keyword(s):  
Phytophthora Infestans ◽  
Genetic Factors ◽  
Specific Resistance ◽  
R Genes

scholarly journals Recent Findings Unravel Genes and Genetic Factors Underlying Leptosphaeria maculans Resistance in Brassica napus and Its Relatives

2020 ◽  
Vol 22 (1) ◽  
pp. 313
Author(s):  
Aldrin Y. Cantila ◽  
Nur Shuhadah Mohd Saad ◽  
Junrey C. Amas ◽  
David Edwards ◽  
Jacqueline Batley
Keyword(s):  
Brassica Napus ◽  
Genetic Factors ◽  
Quantitative Resistance ◽  
Genetic Resistance ◽  
Leptosphaeria Maculans ◽  
Gene Interaction ◽  
R Gene ◽  
R Genes ◽  
Blackleg Resistance ◽  
Avr Gene

Among the Brassica oilseeds, canola (Brassica napus) is the most economically significant globally. However, its production can be limited by blackleg disease, caused by the fungal pathogen Lepstosphaeria maculans. The deployment of resistance genes has been implemented as one of the key strategies to manage the disease. Genetic resistance against blackleg comes in two forms: qualitative resistance, controlled by a single, major resistance gene (R gene), and quantitative resistance (QR), controlled by numerous, small effect loci. R-gene-mediated blackleg resistance has been extensively studied, wherein several genomic regions harbouring R genes against L. maculans have been identified and three of these genes were cloned. These studies advance our understanding of the mechanism of R gene and pathogen avirulence (Avr) gene interaction. Notably, these studies revealed a more complex interaction than originally thought. Advances in genomics help unravel these complexities, providing insights into the genes and genetic factors towards improving blackleg resistance. Here, we aim to discuss the existing R-gene-mediated resistance, make a summary of candidate R genes against the disease, and emphasise the role of players involved in the pathogenicity and resistance. The comprehensive result will allow breeders to improve resistance to L. maculans, thereby increasing yield.

scholarly journals Expression of the Potato Late Blight Resistance Gene Rpi-phu1 and Phytophthora infestans Effectors in the Compatible and Incompatible Interactions in Potato

2017 ◽  
Vol 107 (6) ◽  
pp. 740-748 ◽  
Author(s):  
Emil Stefańczyk ◽  
Sylwester Sobkowiak ◽  
Marta Brylińska ◽  
Jadwiga Śliwka
Keyword(s):  
Late Blight ◽  
Phytophthora Infestans ◽  
Expression Patterns ◽  
Late Blight Resistance ◽  
Blight Resistance ◽  
Transcriptional Level ◽  
R Genes ◽  
Transcript Accumulation ◽  
Breeding Lines ◽  
Additional Resistance

This study describes late blight resistance of potato breeding lines resulting from crosses between cultivar ‘Sárpo Mira’ and Rpi-phu1 gene donors. The progeny is investigated for the presence of Rpi-Smira1 and Rpi-phu1 resistance (R) genes. Interestingly, in detached-leaflet tests, plants with both R genes withstood the infection of the Phytophthora infestans isolate virulent to each gene separately, due to either interaction of these genes or the presence of additional resistance loci. The interaction was studied further in three chosen breeding lines on the transcriptional level. The Rpi-phu1 expression, measured over 5 days, revealed different patterns depending on the outcome of the interaction with P. infestans: it increased in infected plants whereas it remained low and stable when infection was unsuccessful. The expression patterns of P. infestans effectors Avr-vnt1, AvrSmira1, and Avr8, recognized by the Rpi-phu1, Rpi-Smira1, and Rpi-Smira2 genes, respectively, were evaluated in the same experimental setup. This is the first report that the Avr-vnt1 effector expression is not switched off permanently in virulent isolates to avoid recognition by an R protein but can reappear in a postbiotrophic phase and is present constantly when infecting plants without the corresponding R gene. Both a plant and a pathogen can react to the other interacting side by changing the transcript accumulation of R genes or effectors.

scholarly journals Systemic Acquired Resistance Delays Race Shifts to Major Resistance Genes in Bell Pepper

2004 ◽  
Vol 94 (12) ◽  
pp. 1376-1382 ◽  
Author(s):  
A. M. Romero ◽  
D. F. Ritchie
Keyword(s):  
Disease Severity ◽  
Plant Disease Resistance ◽  
Plant Disease ◽  
Systemic Acquired Resistance ◽  
Field Experiments ◽  
Specific Resistance ◽  
Acquired Resistance ◽  
R Genes ◽  
Host Pathogen Interaction ◽  
Major Resistance Genes

The lack of durability of host plant disease resistance is a major problem in disease control. Genotype-specific resistance that involves major resistance (R) genes is especially prone to failure. The compatible (i.e., disease) host-pathogen interaction with systemic acquired resistance (SAR) has been studied extensively, but the incompatible (i.e., resistant) interaction less so. Using the pepper-bacterial spot (causal agent, Xanthomonas axonopodis pv. vesicatoria) pathosystem, we examined the effect of SAR in reducing the occurrence of race-change mutants that defeat R genes in laboratory, greenhouse, and field experiments. Pepper plants carrying one or more R genes were sprayed with the plant defense activator acibenzolar-S-methyl (ASM) and challenged with incompatible strains of the pathogen. In the greenhouse, disease lesions first were observed 3 weeks after inoculation. ASM-treated plants carrying a major R gene had significantly fewer lesions caused by both the incompatible (i.e., hypersensitive) and compatible (i.e., disease) responses than occurred on nonsprayed plants. Bacteria isolated from the disease lesions were confirmed to be race-change mutants. In field experiments, there was a delay in the detection of race-change mutants and a reduction in disease severity. Decreased disease severity was associated with a reduction in the number of race-change mutants and the suppression of disease caused by the race-change mutants. This suggests a possible mechanism related to a decrease in the pathogen population size, which subsequently reduces the number of race-change mutants for the selection pressure of R genes. Thus, inducers of SAR are potentially useful for increasing the durability of genotype-specific resistance conferred by major R genes.

scholarly journals POPULATION STRUCTURE OF PHYTOPHTHORA INFESTANS ON WORLDWIDE SCALE: A REVIEW

2017 ◽  
Vol 29 (2) ◽  
pp. 281
Author(s):  
Khalid Naveed ◽  
Nasir A. Rajputt ◽  
Sajid A. Khan ◽  
Arbab Ahmad
Keyword(s):  
Population Structure ◽  
Late Blight ◽  
Phytophthora Infestans ◽  
Potato Cultivar ◽  
R Genes ◽  
Solanum Bulbocastanum ◽  
Tuber Resistance ◽  
Commercial Potato ◽  
Rb Gene ◽  
Late Blight Of Potato

Phytophthora infestans is a destructive pathogen that causes late blight of potato worldwide. Several sexually and asexually reproducing lineages of the pathogen have been identified and new lineages are more virulent as compared to their parental lineages. A new highly aggressive clonal lineage EU13_A2 has spread into potato fields of Europe, Africa and Asia in place of the older lineages. In North America, 24 clonal lineages US1to US24 have been identified. Despite of sexual reproduction, the overall population of P. infestans in potato and tomato fields is dominated by asexual lineages. Breeding has been done to transfer 'R' genes into commercial potato cultivars through classical breeding and by pyramiding of genes. Defender is the only potato cultivar that has foliar and tuber resistance to late blight. Genetically modified potato with RB gene from Solanum bulbocastanum has been developed but it lacks tuber resistance to disease. This review discusses population structure of P. infestans worldwide and breeding efforts to produce late blight resistant potato.

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