Marker-assisted pyramiding of potato late blight resistance genes Rpi-rzc1 and Rpi-phu1 on di- and tetraploid levels

Abstract Late blight is a disease with the biggest economic impact on potato cultivation worldwide. Pyramiding of the resistance genes originating from potato wild relatives is a breeding strategy that has a potential to produce potato cultivars durably resistant to late blight. Growing such cultivars would allow limiting the intensive chemical control of the disease. The goal of this work was to transfer the late blight resistance gene Rpi-rzc1 from Solanum ruiz-ceballosii to the tetraploid level of cultivated potato and to pyramid it with the Rpi-phu1 gene. We obtained two diploid and, through 4x-2x cross, a tetraploid potato population segregating for the Rpi-rzc1 presence, as well as one diploid and one tetraploid population where both genes were introgressed. In total, 754 progeny clones were tested for resistance to late blight in detached leaflet assays. Pathogen isolates avirulent on plants with both genes and virulent on plants with the Rpi-phu1 were used. The selection was assisted by two PCR markers flanking the Rpi-rzc1 gene and a newly designed, highly specific intragenic marker indicating the Rpi-phu1 gene presence. We obtained 26 diploid and 49 tetraploid potato clones with pyramid of both genes that should enhance the durability and spectrum of their late blight resistance and that can be exploited in potato breeding. The specificity of the marker for the Rpi-phu1 gene and the precision of the Rpi-rzc1 mapping were improved in this work.

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Breeding Late Blight Resistant Potatoes for Organic Farming—a Collaborative Model of Participatory Plant Breeding: the Bioimpuls Project

Potato Research ◽

10.1007/s11540-021-09519-8 ◽

2021 ◽

Author(s):

P. Keijzer ◽

E. T. Lammerts van Bueren ◽

C. J. M. Engelen ◽

R. C. B. Hutten

Keyword(s):

Late Blight ◽

Resistance Genes ◽

Potato Breeding ◽

Late Blight Resistance ◽

Potato Production ◽

Weed Suppression ◽

Blight Resistance ◽

Participatory Plant Breeding ◽

True Seed ◽

Organic Potato

AbstractIn organic potato production, the need for varieties with durable late blight resistance developed through classical breeding programmes is urgent. Besides late blight resistance, other variety characteristics needed in organic potato production are early canopy closure for weed suppression and good tuber dormancy to eliminate the need for (chemical) sprouting inhibition during storage, amongst others. This paper is a unique example of collaboration between researchers, farmers and professional breeders of both large, medium and small breeding companies. The aim of the resulting breeding project, Bioimpuls, was to provide a substantial impulse to both the organic and conventional potato breeding sector by enlarging the access to various sources of late blight resistance. The Bioimpuls activities include providing true seed populations for variety selection with five available sources of R-genes against Phytophthora infestans, early and advanced introgression breeding with six new R-genes, and education and communication. The results achieved over the 11-year period (2009–2019) are analysed. Many true seed populations containing multiple resistance genes are produced and selected, and a constant flow of breeding clones is entering the evaluation and positioning trials of companies. However, it will still take a considerable amount of time before varieties with stacked resistance genes will replace the new resistant single gene varieties entering the market in the next few years. Five out of six new sources of R-genes need more years of backcrossing before they are ready for commercial use. Bioimpuls successfully introduced a training course for farmer breeders, and published a manual for potato breeding.

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Detection of Novel QTLs for Late Blight Resistance Derived from the Wild Potato Species Solanum microdontum and Solanum pampasense

Genes ◽

10.3390/genes11070732 ◽

2020 ◽

Vol 11 (7) ◽

pp. 732

Author(s):

Fergus Meade ◽

Ronald Hutten ◽

Silke Wagener ◽

Vanessa Prigge ◽

Emmet Dalton ◽

...

Keyword(s):

Late Blight ◽

Resistance Genes ◽

Late Blight Resistance ◽

Gene Clusters ◽

Genetic Maps ◽

Blight Resistance ◽

Wild Potato ◽

Wild Potato Species ◽

Potato Species ◽

Solanum Microdontum

Wild potato species continue to be a rich source of genes for resistance to late blight in potato breeding. Whilst many dominant resistance genes from such sources have been characterised and used in breeding, quantitative resistance also offers potential for breeding when the loci underlying the resistance can be identified and tagged using molecular markers. In this study, F1 populations were created from crosses between blight susceptible parents and lines exhibiting strong partial resistance to late blight derived from the South American wild species Solanum microdontum and Solanum pampasense. Both populations exhibited continuous variation for resistance to late blight over multiple field-testing seasons. High density genetic maps were created using single nucleotide polymorphism (SNP) markers, enabling mapping of quantitative trait loci (QTLs) for late blight resistance that were consistently expressed over multiple years in both populations. In the population created with the S. microdontum source, QTLs for resistance consistently expressed over three years and explaining a large portion (21–47%) of the phenotypic variation were found on chromosomes 5 and 6, and a further resistance QTL on chromosome 10, apparently related to foliar development, was discovered in 2016 only. In the population created with the S. pampasense source, QTLs for resistance were found in over two years on chromosomes 11 and 12. For all loci detected consistently across years, the QTLs span known R gene clusters and so they likely represent novel late blight resistance genes. Simple genetic models following the effect of the presence or absence of SNPs associated with consistently effective loci in both populations demonstrated that marker assisted selection (MAS) strategies to introgress and pyramid these loci have potential in resistance breeding strategies.

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Global multi-environment resistance QTL for foliar late blight resistance in tetraploid potato with tropical adaptation

G3 Genes|Genome|Genetics ◽

10.1093/g3journal/jkab251 ◽

2021 ◽

Author(s):

Hannele Lindqvist-Kreuze ◽

Bert De Boeck ◽

Paula Unger ◽

Dorcus Gemenet ◽

Xianping Li ◽

...

Keyword(s):

Late Blight ◽

Fixed Effects ◽

Rapid Evolution ◽

Late Blight Resistance ◽

Selection Strategy ◽

Blight Resistance ◽

Field Exposure ◽

Prediction Ability ◽

Tetraploid Potato

Abstract The identification of environmentally-stable and globally-predictable resistance to potato late blight is challenged by the clonal and polyploid nature of the crop and the rapid evolution of the pathogen. A diversity panel of tetraploid potato germplasm bred for multiple resistance and quality traits was genotyped by genotyping by sequencing (GBS) and evaluated for late blight resistance in three countries where the International Potato Center (CIP) has established breeding work. Health-indexed, in vitro plants of 380 clones and varieties were distributed from CIP headquarters and tuber seed was produced centrally in Peru, China and Ethiopia. Phenotypes were recorded following field exposure to local isolates of Phytophthora infestans. QTL explaining resistance in four experiments conducted across the three countries were identified in chromosome IX, and environment-specific QTL were found in chromosomes III, V, and X. Different genetic models were evaluated for prediction ability to identify best performing germplasm in each and all environments. The best prediction ability (0.868) was identified with the genomic best linear unbiased predictors (GBLUPs) when using the diploid marker data and QTL-linked markers as fixed effects. Genotypes with high levels of resistance in all environments were identified from the B3, LBHT, and B3-LTVR populations. The results show that many of the advanced clones bred in Peru for high levels of late blight resistance maintain their resistance in Ethiopia and China, suggesting that the centralized selection strategy has been largely successful.

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Interspecific potato hybrids as a resource for late blight resistance genes

Russian Agricultural Sciences ◽

10.3103/s1068367414010133 ◽

2014 ◽

Vol 40 (1) ◽

pp. 10-13

Author(s):

E. V. Rogozina ◽

V. A. Kolobaev ◽

E. E. Khavkin ◽

M. A. Kuznetsova ◽

M. P. Beketova ◽

...

Keyword(s):

Late Blight ◽

Resistance Genes ◽

Late Blight Resistance ◽

Blight Resistance ◽

Interspecific Potato Hybrids

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Higher Copy Numbers of the Potato RB Transgene Correspond to Enhanced Transcript and Late Blight Resistance Levels

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-22-4-0437 ◽

2009 ◽

Vol 22 (4) ◽

pp. 437-446 ◽

Cited By ~ 72

Author(s):

James M. Bradeen ◽

Massimo Iorizzo ◽

Dimitre S. Mollov ◽

John Raasch ◽

Lara Colton Kramer ◽

...

Keyword(s):

Disease Resistance ◽

Late Blight ◽

Resistance Gene ◽

Resistance Genes ◽

Rna Silencing ◽

Late Blight Resistance ◽

Blight Resistance ◽

Transcript Levels ◽

Cultivated Potato ◽

Copy Numbers

Late blight of potato ranks among the costliest of crop diseases worldwide. Host resistance offers the best means for controlling late blight, but previously deployed single resistance genes have been short-lived in their effectiveness. The foliar blight resistance gene RB, previously cloned from the wild potato Solanum bulbocastanum, has proven effective in greenhouse tests of transgenic cultivated potato. In this study, we examined the effects of the RB transgene on foliar late blight resistance in transgenic cultivated potato under field production conditions. In a two-year replicated trial, the RB transgene, under the control of its endogenous promoter, provided effective disease resistance in various genetic backgrounds, including commercially prominent potato cultivars, without fungicides. RB copy numbers and transcript levels were estimated with transgene-specific assays. Disease resistance was enhanced as copy numbers and transcript levels increased. The RB gene, like many other disease resistance genes, is constitutively transcribed at low levels. Transgenic potato lines with an estimated 15 copies of the RB transgene maintain high RB transcript levels and were ranked among the most resistant of 57 lines tested. We conclude that even in these ultra–high copy number lines, innate RNA silencing mechanisms have not been fully activated. Our findings suggest resistance-gene transcript levels may have to surpass a threshold before triggering RNA silencing. Strategies for the deployment of RB are discussed in light of the current research.

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