The R1 gene for potato resistance to late blight (Phytophthora infestans) belongs to the leucine zipper/NBS/LRR class of plant resistance genes (original) (raw)
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Molecular Plant-Microbe Interactions, 2004
The R3 locus of potato (Solanum tuberosum L.) confers full resistance to avirulent isolates of Phytophthora infestans, the causal agent of late blight. R3 resides in the distal part of chromosome 11 and segregates in a potato mapping population, from which a well-saturated amplified fragment length polymorphism map is available. Using a population of 1,748 plants, we constructed a high-resolution genetic map at the R3 locus. Using the combination of fine mapping and accurate disease testing with specific P. infestans isolates, we detected that the R3 locus is composed of two genes with distinct specificities. The two genes R3a and R3b are 0.4 cM apart and have both been introgressed from S. demissum, the ‘donor’ species of most characterized race-specific R genes to P. infestans. A natural recombinant between R3a and R3b was discovered in one accession of S. demissum. The synteny between the R3 locus and the tomato I2 locus is discussed.
Theoretical and Applied Genetics, 2006
The R10 and R11 late blight differentials of Black (tetraploid clones 3681ad1 and 5008ab6) were crossed with the susceptible potato (Solanum tuberosum) cultivar Maris Piper and the progeny were assessed for blight resistance in a whole plant glasshouse test using race 1,2,3,4,6,7 of Phytophthora infestans. The disease scores for the R10 population displayed a continuous distribution whereas the progeny in the R11 population could be categorised as resistant or susceptible. A bulk segregant analysis using amplified fragment length polymorphism assays was done on the ten most resistant and ten most susceptible progeny in each population and two closely linked markers were found to be associated with resistance. R11 mapped to 8.5 cM from marker PAG/MAAG_172.3 and R10 mapped as a quantitative trait locus in which marker PAC/MATC_264.1 explained 56.9% of the variation in disease scores. The results were consistent with R10 and R11 being allelic versions of genes at the R3 locus on chromosome 11. The implications are discussed for mapping R-genes which fail to give complete immunity to a pathogen.
Plant Journal, 2005
Comparative genomics provides a tool to utilize the exponentially increasing sequence information from model plants to clone agronomically important genes from less studied crop species. Plant disease resistance (R) loci frequently lack synteny between related species of cereals and crucifers but appear to be positionally well conserved in the Solanaceae. In this report, we adopted a local RGA approach using genomic information from the model Solanaceous plant tomato to isolate R3a, a potato gene that confers race-specific resistance to the late blight pathogen Phytophthora infestans. R3a is a member of the R3 complex locus on chromosome 11. Comparative analyses of the R3 complex locus with the corresponding I2 complex locus in tomato suggest that this is an ancient locus involved in plant innate immunity against oomycete and fungal pathogens. However, the R3 complex locus has evolved after divergence from tomato and the locus has experienced a significant expansion in potato without disruption of the flanking colinearity. This expansion has resulted in an increase in the number of R genes and in functional diversification, which has probably been driven by the co-evolutionary history between P. infestans and its host potato. Constitutive expression was observed for the R3a gene, as well as some of its paralogues whose functions remain unknown.
Comparative genomics enabled the isolation of the R3a late blight resistance gene in potato
Plant Journal, 2005
Comparative genomics provides a tool to utilize the exponentially increasing sequence information from model plants to clone agronomically important genes from less studied crop species. Plant disease resistance (R) loci frequently lack synteny between related species of cereals and crucifers but appear to be positionally well conserved in the Solanaceae. In this report, we adopted a local RGA approach using genomic information from the model Solanaceous plant tomato to isolate R3a, a potato gene that confers race-specific resistance to the late blight pathogen Phytophthora infestans. R3a is a member of the R3 complex locus on chromosome 11. Comparative analyses of the R3 complex locus with the corresponding I2 complex locus in tomato suggest that this is an ancient locus involved in plant innate immunity against oomycete and fungal pathogens. However, the R3 complex locus has evolved after divergence from tomato and the locus has experienced a significant expansion in potato without disruption of the flanking colinearity. This expansion has resulted in an increase in the number of R genes and in functional diversification, which has probably been driven by the co-evolutionary history between P. infestans and its host potato. Constitutive expression was observed for the R3a gene, as well as some of its paralogues whose functions remain unknown.
Silencing of six susceptibility genes results in potato late blight resistance
Transgenic research, 2016
Phytophthora infestans, the causal agent of late blight, is a major threat to commercial potato production worldwide. Significant costs are required for crop protection to secure yield. Many dominant genes for resistance (R-genes) to potato late blight have been identified, and some of these R-genes have been applied in potato breeding. However, the P. infestans population rapidly accumulates new virulent strains that render R-genes ineffective. Here we introduce a new class of resistance which is based on the loss-of-function of a susceptibility gene (S-gene) encoding a product exploited by pathogens during infection and colonization. Impaired S-genes primarily result in recessive resistance traits in contrast to recognition-based resistance that is governed by dominant R-genes. In Arabidopsis thaliana, many S-genes have been detected in screens of mutant populations. In the present study, we selected 11 A. thaliana S-genes and silenced orthologous genes in the potato cultivar Desi...
The effect of pyramiding Phytophthora infestans resistance genes R Pi-mcd1 and R Pi-ber in potato
Theoretical and Applied Genetics, 2010
Despite eVorts to control late blight in potatoes by introducing R pi-genes from wild species into cultivated potato, there are still concerns regarding the durability and level of resistance. Pyramiding R pi-genes can be a solution to increase both durability and level of resistance. In this study, two resistance genes, R Pi-mcd1 and R Pi-ber , introgressed from the wild tuber-bearing potato species Solanum microdontum and S. berthaultii were combined in a diploid S. tuberosum population. Individual genotypes from this population were classiWed after four groups, carrying no R pi-gene, with only R Pi-mcd1 , with only R Pi-ber , and a group with the pyramided R Pi-mcd1 and R Pi-ber by means of tightly linked molecular markers. The levels of resistance between the groups were compared in a Weld experiment in 2007. The group with R Pi-mcd1 showed a signiWcant delay to reach 50% infection of the leaf area of 3 days. The group with R Pi-ber showed a delay of 3 weeks. The resistance level in the pyramid group suggested an additive eVect of R Pi-mcd1 with R Pi-ber. This suggests that potato breeding can beneWt from combining individual R pi-genes, irrespective of the weak eVect of R Pi-mcd1 or the strong eVect of R Pi-ber .
The Plant Journal, 2003
Late blight, caused by the oomycete pathogen Phytophthora infestans, is the most devastating disease for potato cultivation. Here, we describe the positional cloning of the Rpi-blb1 gene from the wild potato species Solanum bulbocastanum known for its high levels of resistance to late blight. The Rpi-blb1 locus, which confers full resistance to complex isolates of P. infestans and for which race speci®city has not yet been demonstrated, was mapped in an intraspeci®c S. bulbocastanum population on chromosome 8, 0.3 cM from marker CT88. Molecular analysis of a bacterial arti®cial chromosome (BAC) clone spanning the Rpi-blb1 locus identi®ed a cluster of four candidate resistance gene analogues of the coiled coil, nucleotide-binding site, leucine-rich repeat (CC-NBS-LRR) class of plant resistance (R ) genes. One of these candidate genes, designated the Rpi-blb1 gene, was able to complement the susceptible phenotype in a S. tuberosum and tomato background, demonstrating the potential of interspeci®c transfer of broad-spectrum late blight resistance to cultivated Solanaceae from sexually incompatible host species. Paired comparisons of synonymous and non-synonymous nucleotide substitutions between different regions of Rpi-blb1 paralogues revealed high levels of synonymous divergence, also in the LRR region. Although amino acid diversity between Rpi-blb1 homologues is centred on the putative solvent exposed residues of the LRRs, the majority of nucleotide differences in this region have not resulted in an amino acid change, suggesting conservation of function. These data suggest that Rpi-blb1 is relatively old and may be subject to balancing selection.
The impact of R1and R3a genes on tuber resistance to late blight of the potato breeding clones
2016
Potato breeding clones were evaluated for resistance to late blight (agent Phytophthora infestans) using tuber inoculation tests and for presence of the resistance alleles of R1 and R3a genes in polymerase chain reaction tests. Among clones tested those expressing high, moderate and low resistance were identified. The data were analysed for the impact of R1 and R3a genes on tuber resistance to late blight in tested plant material. In previous evaluations performed on smaller amount of clones the tuber resistance levels significantly depended on presence/absence of the resistance allele of R3a gene and did not depend on presence of R1 gene allele. In the current study the statistical analyses did not prove the significant difference in resistance levels depending on presence of the resistance alleles, neither of R1 gene, nor of R3a gene. Tuber resistant clones bearing R3a gene resistance alleles still noticeably prevailed over the clones bearing the alleles of R1 gene as well as over...
Potato Research, 2009
Cultivated potato is susceptible to many pests and pathogens, none of which is more of a threat to potato agriculture than the late blight disease, caused by the oomycete Phytophthora infestans (Mont.) de Bary. To date all efforts to thwart this most adaptive of pathogens have failed, and early attempts to deploy 'R genes' introgressed from the wild Mexican hexaploid Solanum demissum ended in abject failure. With the advent of facile gene mapping and cloning, allied to knowledge of plant resistance gene structure, renewed efforts are leading to mapping and isolation of new sources of late blight resistance in potato wild species, many of which are being performed under the auspices of the BIOEXPLOIT project (Sub-project 2). We document recent advances in late blight resistance gene mapping and isolation, and postulate how these genes, allied to knowledge of pathogen effectors and their recognition specificity, may greatly enhance our chances of halting the progress of late blight disease in potato crops worldwide.
Functional analysis of potato genes involved in quantitative resistance to Phytophthora infestans
Molecular Biology Reports, 2013
The most significant threat to potato production worldwide is the late blight disease, which is caused by the oomycete pathogen Phytophthora infestans. Based on previous cDNA microarrays and cDNA-amplified fragment length polymorphism analysis, 63 candidate genes that are expected to contribute to developing a durable resistance to late blight were selected for further functional analysis. We performed virus-induced gene silencing (VIGS) to these candidate genes on both Nicotiana benthamiana and potato, subsequently inoculated detached leaves and assessed the resistance level. Ten genes decreased the resistance to P. infestans after VIGS treatment. Among those, a lipoxygenase (LOX; EC 1.13.11.12) and a suberization-associated anionic peroxidase affected the resistance in both N. benthamiana and potato. Our results identify genes that may play a role in quantitative resistance mechanisms to late blight.