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Massimo Iorizzo - One of the best experts on this subject based on the ideXlab platform.

  • a dart marker based linkage map for wild potato Solanum Bulbocastanum facilitates structural comparisons between Solanum a and b genomes
    BMC Genetics, 2014
    Co-Authors: Massimo Iorizzo, Liangliang Gao, Harpartap Mann, Alessandra Traini, Maria Luisa Chiusano, Andrzej Kilian, Riccardo Aversano, Domenico Carputo
    Abstract:

    Wild potato Solanum Bulbocastanum is a rich source of genetic resistance against a variety of pathogens. It belongs to a taxonomic group of wild potato species sexually isolated from cultivated potato. Consistent with genetic isolation, previous studies suggested that the genome of S. Bulbocastanum (B genome) is structurally distinct from that of cultivated potato (A genome). However, the genome architecture of the species remains largely uncharacterized. The current study employed Diversity Arrays Technology (DArT) to generate a linkage map for S. Bulbocastanum and compare its genome architecture with those of potato and tomato. Two S. Bulbocastanum parental linkage maps comprising 458 and 138 DArT markers were constructed. The integrated map comprises 401 non-redundant markers distributed across 12 linkage groups for a total length of 645 cM. Sequencing and alignment of DArT clones to reference physical maps from tomato and cultivated potato allowed direct comparison of marker orders between species. A total of nine genomic segments informative in comparative genomic studies were identified. Seven genome rearrangements correspond to previously-reported structural changes that have occurred since the speciation of tomato and potato. We also identified two S. Bulbocastanum genomic regions that differ from cultivated potato, suggesting possible chromosome divergence between Solanum A and B genomes. The linkage map developed here is the first medium density map of S. Bulbocastanum and will assist mapping of agronomical genes and QTLs. The structural comparison with potato and tomato physical maps is the first genome wide comparison between Solanum A and B genomes and establishes a foundation for further investigation of B genome-specific structural chromosome rearrangements.

  • higher copy numbers of the potato rb transgene correspond to enhanced transcript and late blight resistance levels
    Molecular Plant-microbe Interactions, 2009
    Co-Authors: James M Bradeen, John A Raasch, Sandra Austinphillips, Massimo Iorizzo, Benjamin P Millett, Dimitre Mollov, Lara C Kramer, Jiming Jiang, Domenico Carputo
    Abstract:

    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.

  • changes in disease resistance phenotypes associated with plant physiological age are not caused by variation in r gene transcript abundance
    Molecular Plant-microbe Interactions, 2009
    Co-Authors: Benjamin P Millett, Domenico Carputo, Massimo Iorizzo, Dimitre Mollov, James M Bradeen
    Abstract:

    Foliar late blight is one of the most important diseases of potato. Foliar blight resistance has been shown to change as a plant ages. In other pathosystems, resistance (R) gene transcript levels appear to be correlated to disease resistance. The cloning of the broad-spectrum, foliar blight resistance gene RB provided the opportunity to explore how foliar blight resistance and R-gene transcript levels vary with plant age. Plants of Solanum Bulbocastanum PT29, from which RB, including the native promoter and other flanking regions, was cloned, and S. tuberosum cv. Dark Red Norland (nontransformed and RB-transformed) representing three different developmental stages were screened for resistance to late blight and RB transcript levels. Preflowering plants of all genotypes exhibited the highest levels of resistance, followed by postflowering and near-senescing plants. The RB transgene significantly affected resistance, enhancing resistance levels of all RB-containing lines, especially in younger plants. RB tr...

Jiming Jiang - One of the best experts on this subject based on the ideXlab platform.

  • constitutively expressed rb gene confers a high level but unregulated resistance to potato late blight
    American Journal of Potato Research, 2018
    Co-Authors: S M Wielgus, Jiming Jiang, Pudota B Bhaskar, Saowapa Duangpan
    Abstract:

    The RB gene, which was cloned from the wild potato species Solanum Bulbocastanum, confers a high level of broad spectrum resistance to various strains of Phytophthora infestans, the causal agent of potato late blight. The level of RB-mediated resistance is correlated with the amount of RB transcripts in transgenic potato lines containing RB gene(s) driven by its native promoter. To assess whether the level of RB-mediated resistance can be further enhanced by overexpression of the RB gene, multiple transgenic potato lines containing RB gene(s) driven by the cauliflower mosaic virus (CaMV) 35S promoter were developed. Surprisingly, all 35S::RB transgenic lines with one or several copies of the RB gene showed a similar level of late blight resistance. In parallel, a statistically similar amount of RB transcript was observed among all resistant transgenic lines with different copy numbers of the RB gene. In addition, the levels of RB gene transcription in the 35S::RB transgenic potato lines were the same or lower than in transgenic lines containing the RB gene driven by its native promoter. Thus, developing transgenic potato lines using RB with the native promoter will be the best approach to deploy this gene for combating late blight.

  • correlation between transcript abundance of the rb gene and the level of the rb mediated late blight resistance in potato
    Molecular Plant-microbe Interactions, 2009
    Co-Authors: Lara C Kramer, S M Wielgus, Mallory J Choudoir, Pudota B Bhaskar, Jiming Jiang
    Abstract:

    Numerous disease-resistance genes have been cloned and characterized in various plant species. Only a few of these reported genes were transcriptionally induced or had enhanced transcription upon pathogen infection. Here, we report that transcription of the RB gene, which was cloned from the wild potato species Solanum Bulbocastanum and confers resistance to potato late blight, was significantly increased after inoculation with the late blight pathogen Phytophthora infestans. Different RB transgenic lines showed different levels of resistance, which were correlated with the amounts of RB transcript in the transgenic plants. Different transgenic lines also showed different patterns of RB transcription 1, 3, and 5 days after P. infestans inoculation. Interestingly, the RB gene showed a higher basal level of transcription and a more dramatic transcriptional increase upon inoculation in S. Bulbocastanum than in all potato transgenic lines. Our results revealed a predictive correlation between transcript abundance of the RB gene and the level of the RB-mediated late blight resistance. High level of resistance was associated with a combination of rapid RB transcript induction immediately after pathogen infection followed by the steady production of RB transcript. Thus, the transcription level of the RB gene provides a valuable marker for selecting and deploying RB-containing potato lines for late blight control.

  • higher copy numbers of the potato rb transgene correspond to enhanced transcript and late blight resistance levels
    Molecular Plant-microbe Interactions, 2009
    Co-Authors: James M Bradeen, John A Raasch, Sandra Austinphillips, Massimo Iorizzo, Benjamin P Millett, Dimitre Mollov, Lara C Kramer, Jiming Jiang, Domenico Carputo
    Abstract:

    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.

  • performance of transgenic potato containing the late blight resistance gene rb
    Plant Disease, 2008
    Co-Authors: Dennis Halterman, S M Wielgus, Lara C Kramer, Jiming Jiang
    Abstract:

    Late blight of potato, caused by Phytophthora infestans, is one of the most devastating diseases of potato. A major late blight resistance gene, called RB, previously was identified in the wild potato species Solanum Bulbocastanum through map-based cloning. The full-length gene coding sequence, including the open reading frame and promoter, has been integrated into cultivated potato (S. tuberosum) using Agrobacterium-mediated transformation. RB-containing transgenic plants were challenged with P. infestans under optimal late blight conditions in greenhouse experiments. All transgenic lines containing RB exhibited strong foliar resistance. Field-grown transgenic tubers also were tested for resistance to P. infestans. In contrast to the foliar resistance phenotype, RB-containing tubers did not exhibit increased resistance. Two years of field trials were used to ascertain whether the presence of RB had any effect on tuber yield. We were unable to detect any significant effect on tuber size or yield after addition of the resistance gene to several S. tuberosum cultivars.

  • sgt1 but not rar1 is essential for the rb mediated broad spectrum resistance to potato late blight
    BMC Plant Biology, 2008
    Co-Authors: Pudota B Bhaskar, S M Wielgus, John A Raasch, Sandra Austinphillips, Lara C Kramer, Pavel Neumann, Jiming Jiang
    Abstract:

    Late blight is the most serious potato disease world-wide. The most effective and environmentally sound way for controlling late blight is to incorporate natural resistance into potato cultivars. Several late blight resistance genes have been cloned recently. However, there is almost no information available about the resistance pathways mediated by any of those genes. We previously cloned a late blight resistance gene, RB, from a diploid wild potato species Solanum Bulbocastanum. Transgenic potato lines containing a single RB gene showed a rate-limiting resistance against all known races of Phytophthora infestans, the late blight pathogen. To better understand the RB-mediated resistance we silenced the potato Rar1 and Sgt1 genes that have been implicated in mediating disease resistance responses against various plant pathogens and pests. The Rar1 and Sgt1 genes of a RB-containing potato clone were silenced using a RNA interference (RNAi)-based approach. All of the silenced potato plants displayed phenotypically normal growth. The late blight resistance of the Rar1 and Sgt1 silenced lines were evaluated by a traditional greenhouse inoculation method and quantified using a GFP-tagged P. infestans strain. The resistance of the Rar1-silenced plants was not affected. However, silencing of the Sgt1 gene abolished the RB-mediated resistance. Our study shows that silencing of the Sgt1 gene in potato does not result in lethality. However, the Sgt1 gene is essential for the RB-mediated late blight resistance. In contrast, the Rar1 gene is not required for RB-mediated resistance. These results provide additional evidence for the universal role of the Sgt1 gene in various R gene-mediated plant defense responses.

Domenico Carputo - One of the best experts on this subject based on the ideXlab platform.

  • Glycoalkaloid Profile in Potato Haploids Derived from Solanum tuberosum– S. Bulbocastanum Somatic Hybrids
    2016
    Co-Authors: Domenico Carputo, Luigi Frusciante, S. Savarese, Riccardo Aversano, Anna Andolfi, Alessio Cimmino, Antonio Evidente
    Abstract:

    Cultivated and wild potato species synthesize a wide variety of steroidal glycoalkaloids (GA) that may affect either human health or biotic stress resistance. Therefore, GA composition must be a major criterion in the evaluation of breeding products when species genomes are merged and/or manipulated. This work reports the results of GA analysis performed on unique haploid (2n2x24) plants obtained from tetraploid (2n4x48) Solanum Bulbocastanum–S. tuberosum hybrids through in vitro anther culture. Glycoalkaloids were extracted from tubers and analyzed by HPLC. Haploids generally showed the occurrence of parental GA. However, in several cases loss of parental GA and gain of new GA lacking in the parents was observed. It may be hypothesized that new GA profiles of our haploids is the result of either genetic recombination or combinatorial biochemistry events. To highlight differences between haploids and parents, soluble proteins and antioxidant activities were also determined. Both were always higher in haploids compared to their parents. The nature of the newly formed GAs will be further investigated, because they may represent new metabolites that can be used against pest and diseases, or are useful for human health. Introduction. – Glycoalkaloids (GA) are typical secondary metabolites occurring in a wide range of plants. They may have both adverse and beneficial effects. High G

  • a dart marker based linkage map for wild potato Solanum Bulbocastanum facilitates structural comparisons between Solanum a and b genomes
    BMC Genetics, 2014
    Co-Authors: Massimo Iorizzo, Liangliang Gao, Harpartap Mann, Alessandra Traini, Maria Luisa Chiusano, Andrzej Kilian, Riccardo Aversano, Domenico Carputo
    Abstract:

    Wild potato Solanum Bulbocastanum is a rich source of genetic resistance against a variety of pathogens. It belongs to a taxonomic group of wild potato species sexually isolated from cultivated potato. Consistent with genetic isolation, previous studies suggested that the genome of S. Bulbocastanum (B genome) is structurally distinct from that of cultivated potato (A genome). However, the genome architecture of the species remains largely uncharacterized. The current study employed Diversity Arrays Technology (DArT) to generate a linkage map for S. Bulbocastanum and compare its genome architecture with those of potato and tomato. Two S. Bulbocastanum parental linkage maps comprising 458 and 138 DArT markers were constructed. The integrated map comprises 401 non-redundant markers distributed across 12 linkage groups for a total length of 645 cM. Sequencing and alignment of DArT clones to reference physical maps from tomato and cultivated potato allowed direct comparison of marker orders between species. A total of nine genomic segments informative in comparative genomic studies were identified. Seven genome rearrangements correspond to previously-reported structural changes that have occurred since the speciation of tomato and potato. We also identified two S. Bulbocastanum genomic regions that differ from cultivated potato, suggesting possible chromosome divergence between Solanum A and B genomes. The linkage map developed here is the first medium density map of S. Bulbocastanum and will assist mapping of agronomical genes and QTLs. The structural comparison with potato and tomato physical maps is the first genome wide comparison between Solanum A and B genomes and establishes a foundation for further investigation of B genome-specific structural chromosome rearrangements.

  • glycoalkaloid profile in potato haploids derived from Solanum tuberosum s Bulbocastanum somatic hybrids
    Chemistry & Biodiversity, 2010
    Co-Authors: Domenico Carputo, Luigi Frusciante, S. Savarese, Riccardo Aversano, Anna Andolfi, Alessio Cimmino, Antonio Evidente
    Abstract:

    Cultivated and wild potato species synthesize a wide variety of steroidal glycoalkaloids (GA) that may affect either human health or biotic stress resistance. Therefore, GA composition must be a major criterion in the evaluation of breeding products when species genomes are merged and/or manipulated. This work reports the results of GA analysis performed on unique haploid (2n ¼ 2x ¼ 24) plants obtained from tetraploid (2n ¼ 4x ¼ 48) Solanum Bulbocastanum – S. tuberosum hybrids through in vitro anther culture. Glycoalkaloids were extracted from tubers and analyzed by HPLC. Haploids generally showed the occurrence of parental GA. However, in several cases loss of parental GA and gain of new GA lacking in the parents was observed. It may be hypothesized that new GA profiles of our haploids is the result of either genetic recombination or combinatorial biochemistry events. To highlight differences between haploids and parents, soluble proteins and antioxidant activities were also determined. Both were always higher in haploids compared to their parents. The nature of the newly formed GAs will be further investigated, because they may represent new metabolites that can be used against pest and diseases, or are useful for human health.

  • higher copy numbers of the potato rb transgene correspond to enhanced transcript and late blight resistance levels
    Molecular Plant-microbe Interactions, 2009
    Co-Authors: James M Bradeen, John A Raasch, Sandra Austinphillips, Massimo Iorizzo, Benjamin P Millett, Dimitre Mollov, Lara C Kramer, Jiming Jiang, Domenico Carputo
    Abstract:

    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.

  • changes in disease resistance phenotypes associated with plant physiological age are not caused by variation in r gene transcript abundance
    Molecular Plant-microbe Interactions, 2009
    Co-Authors: Benjamin P Millett, Domenico Carputo, Massimo Iorizzo, Dimitre Mollov, James M Bradeen
    Abstract:

    Foliar late blight is one of the most important diseases of potato. Foliar blight resistance has been shown to change as a plant ages. In other pathosystems, resistance (R) gene transcript levels appear to be correlated to disease resistance. The cloning of the broad-spectrum, foliar blight resistance gene RB provided the opportunity to explore how foliar blight resistance and R-gene transcript levels vary with plant age. Plants of Solanum Bulbocastanum PT29, from which RB, including the native promoter and other flanking regions, was cloned, and S. tuberosum cv. Dark Red Norland (nontransformed and RB-transformed) representing three different developmental stages were screened for resistance to late blight and RB transcript levels. Preflowering plants of all genotypes exhibited the highest levels of resistance, followed by postflowering and near-senescing plants. The RB transgene significantly affected resistance, enhancing resistance levels of all RB-containing lines, especially in younger plants. RB tr...

S M Wielgus - One of the best experts on this subject based on the ideXlab platform.

  • constitutively expressed rb gene confers a high level but unregulated resistance to potato late blight
    American Journal of Potato Research, 2018
    Co-Authors: S M Wielgus, Jiming Jiang, Pudota B Bhaskar, Saowapa Duangpan
    Abstract:

    The RB gene, which was cloned from the wild potato species Solanum Bulbocastanum, confers a high level of broad spectrum resistance to various strains of Phytophthora infestans, the causal agent of potato late blight. The level of RB-mediated resistance is correlated with the amount of RB transcripts in transgenic potato lines containing RB gene(s) driven by its native promoter. To assess whether the level of RB-mediated resistance can be further enhanced by overexpression of the RB gene, multiple transgenic potato lines containing RB gene(s) driven by the cauliflower mosaic virus (CaMV) 35S promoter were developed. Surprisingly, all 35S::RB transgenic lines with one or several copies of the RB gene showed a similar level of late blight resistance. In parallel, a statistically similar amount of RB transcript was observed among all resistant transgenic lines with different copy numbers of the RB gene. In addition, the levels of RB gene transcription in the 35S::RB transgenic potato lines were the same or lower than in transgenic lines containing the RB gene driven by its native promoter. Thus, developing transgenic potato lines using RB with the native promoter will be the best approach to deploy this gene for combating late blight.

  • correlation between transcript abundance of the rb gene and the level of the rb mediated late blight resistance in potato
    Molecular Plant-microbe Interactions, 2009
    Co-Authors: Lara C Kramer, S M Wielgus, Mallory J Choudoir, Pudota B Bhaskar, Jiming Jiang
    Abstract:

    Numerous disease-resistance genes have been cloned and characterized in various plant species. Only a few of these reported genes were transcriptionally induced or had enhanced transcription upon pathogen infection. Here, we report that transcription of the RB gene, which was cloned from the wild potato species Solanum Bulbocastanum and confers resistance to potato late blight, was significantly increased after inoculation with the late blight pathogen Phytophthora infestans. Different RB transgenic lines showed different levels of resistance, which were correlated with the amounts of RB transcript in the transgenic plants. Different transgenic lines also showed different patterns of RB transcription 1, 3, and 5 days after P. infestans inoculation. Interestingly, the RB gene showed a higher basal level of transcription and a more dramatic transcriptional increase upon inoculation in S. Bulbocastanum than in all potato transgenic lines. Our results revealed a predictive correlation between transcript abundance of the RB gene and the level of the RB-mediated late blight resistance. High level of resistance was associated with a combination of rapid RB transcript induction immediately after pathogen infection followed by the steady production of RB transcript. Thus, the transcription level of the RB gene provides a valuable marker for selecting and deploying RB-containing potato lines for late blight control.

  • performance of transgenic potato containing the late blight resistance gene rb
    Plant Disease, 2008
    Co-Authors: Dennis Halterman, S M Wielgus, Lara C Kramer, Jiming Jiang
    Abstract:

    Late blight of potato, caused by Phytophthora infestans, is one of the most devastating diseases of potato. A major late blight resistance gene, called RB, previously was identified in the wild potato species Solanum Bulbocastanum through map-based cloning. The full-length gene coding sequence, including the open reading frame and promoter, has been integrated into cultivated potato (S. tuberosum) using Agrobacterium-mediated transformation. RB-containing transgenic plants were challenged with P. infestans under optimal late blight conditions in greenhouse experiments. All transgenic lines containing RB exhibited strong foliar resistance. Field-grown transgenic tubers also were tested for resistance to P. infestans. In contrast to the foliar resistance phenotype, RB-containing tubers did not exhibit increased resistance. Two years of field trials were used to ascertain whether the presence of RB had any effect on tuber yield. We were unable to detect any significant effect on tuber size or yield after addition of the resistance gene to several S. tuberosum cultivars.

  • sgt1 but not rar1 is essential for the rb mediated broad spectrum resistance to potato late blight
    BMC Plant Biology, 2008
    Co-Authors: Pudota B Bhaskar, S M Wielgus, John A Raasch, Sandra Austinphillips, Lara C Kramer, Pavel Neumann, Jiming Jiang
    Abstract:

    Late blight is the most serious potato disease world-wide. The most effective and environmentally sound way for controlling late blight is to incorporate natural resistance into potato cultivars. Several late blight resistance genes have been cloned recently. However, there is almost no information available about the resistance pathways mediated by any of those genes. We previously cloned a late blight resistance gene, RB, from a diploid wild potato species Solanum Bulbocastanum. Transgenic potato lines containing a single RB gene showed a rate-limiting resistance against all known races of Phytophthora infestans, the late blight pathogen. To better understand the RB-mediated resistance we silenced the potato Rar1 and Sgt1 genes that have been implicated in mediating disease resistance responses against various plant pathogens and pests. The Rar1 and Sgt1 genes of a RB-containing potato clone were silenced using a RNA interference (RNAi)-based approach. All of the silenced potato plants displayed phenotypically normal growth. The late blight resistance of the Rar1 and Sgt1 silenced lines were evaluated by a traditional greenhouse inoculation method and quantified using a GFP-tagged P. infestans strain. The resistance of the Rar1-silenced plants was not affected. However, silencing of the Sgt1 gene abolished the RB-mediated resistance. Our study shows that silencing of the Sgt1 gene in potato does not result in lethality. However, the Sgt1 gene is essential for the RB-mediated late blight resistance. In contrast, the Rar1 gene is not required for RB-mediated resistance. These results provide additional evidence for the universal role of the Sgt1 gene in various R gene-mediated plant defense responses.

  • analysis of the introgression of Solanum Bulbocastanum dna into potato breeding lines
    Molecular Genetics and Genomics, 2001
    Co-Authors: S K Naess, James M Bradeen, S M Wielgus, Geraldine T Haberlach, J M Mcgrath, J P Helgeson
    Abstract:

    Somatic hybrids have been obtained between potato and Solanum Bulbocastanum PI 245310, a Mexican diploid (2n=2x=24) species. Through restriction fragment length polymorphism (RFLP) and randomly amplified polymorphic DNA (RAPD) analyses it was found that the somatic hybrids contain each chromosome of the diploid parent and that the synteny of RFLP markers noted with tomato, potato and S. brevidens is largely maintained in S. Bulbocastanum. RFLP analyses of BC1 progeny of two different hybrids indicated that a substantial number of markers were either lost or were heterozygous, in marked contrast with results previously noted with S. brevidens. A RAPD map for all 12 chromosomes of S. Bulbocastanum was prepared and marker transmission was followed in three BC2 populations. Results with chromosomes 3, 8 and 10 from these populations are compared.

Marc Ghislain - One of the best experts on this subject based on the ideXlab platform.

  • stacking three late blight resistance genes from wild species directly into african highland potato varieties confers complete field resistance to local blight races
    Plant Biotechnology Journal, 2019
    Co-Authors: Marc Ghislain, Maria Lupe Roman, Cristina Rivera, Gregory A Forbes, Soledad Gamboa, Arinaitwe Abel Byarugaba, Eric Magembe, Anne Njoroge, Jose Carlos Tovar, Jan Kreuze
    Abstract:

    Considered responsible for one million deaths in Ireland and widespread famine in the European continent during the 1840s, late blight, caused by Phytophthora infestans, remains the most devastating disease of potato (Solanum tuberosum L.) with about 15%-30% annual yield loss in sub-Saharan Africa, affecting mainly smallholder farmers. We show here that the transfer of three resistance (R) genes from wild relatives [RB, Rpi-blb2 from Solanum Bulbocastanum and Rpi-vnt1.1 from S. venturii] into potato provided complete resistance in the field over several seasons. We observed that the stacking of the three R genes produced a high frequency of transgenic events with resistance to late blight. In the field, 13 resistant transgenic events with the 3R-gene stack from the potato varieties 'Desiree' and 'Victoria' grew normally without showing pathogen damage and without any fungicide spray, whereas their non-transgenic equivalent varieties were rapidly killed. Characteristics of the local pathogen population suggest that the resistance to late blight may be long-lasting because it has low diversity, and essentially consists of the single lineage, 2_A1, which expresses the cognate avirulence effector genes. Yields of two transgenic events from 'Desiree' and 'Victoria' grown without fungicide to reflect small-scale farm holders were estimated to be 29 and 45 t/ha respectively. This represents a three to four-fold increase over the national average. Thus, these late blight resistant potato varieties, which are the farmers' preferred varieties, could be rapidly adopted and bring significant income to smallholder farmers in sub-Saharan Africa.

  • rpi blb2 gene from Solanum Bulbocastanum confers extreme resistance to late blight disease in potato
    Plant Cell Tissue and Organ Culture, 2016
    Co-Authors: Jeanette Orbegozo, Maria Lupe Roman, Cristina Rivera, S Gamboa, Jose C Tovar, Gregory A Forbes, Hannele Lindqvistkreuze, Jan Kreuze, Marc Ghislain
    Abstract:

    The Rpi-blb2 gene (R gene) from the Mexican wild potato species, Solanum Bulbocastanum, was introduced into the potato variety Desiree by agro-infection in order to confer resistance to late blight which is still the most important disease of the potato worldwide. A total of 148 putative transgenic events was obtained by selection based on hygromycin resistance of which 127 appeared to contain the Rpi-blb2 gene. To rapidly identify the highly resistant transgenic events, we used an in vitro assay with one isolate of Phytophthora infestans and a whole-plant assay with two isolates. Nine transgenic events were highly resistant to both isolates and four of these contained single copy T-DNA and did not contain backbone vector sequences. The transcript abundance of Rpi-blb2 was low in infected and uninfected leaves and did not correlate with the resistance level determined in whole plants. We proceeded with high dose inoculation of whole plants of three highly and moderately resistant transgenic events, which resulted in lesions with low levels of sporulation in a few cases. Reinfection was not successful in any of the cases. Hence our results show that a high level of resistance to LB, including extreme resistance, can be obtained through the Rpi-blb2 gene and that heavy inoculation did not readily increase virulence in our test conditions. These transgenic events will be used for either multi-line deployment or R gene stacking by conventional breeding in order to release late blight resistant varieties which will need limited fungicide use, if any.

  • Resistance to Phytophthora infestans EC-1 clonal lineage in Solanum tuberosum by introducing the RB gene
    Universidad Nacional Mayor de San Marcos, 2015
    Co-Authors: Maria Lupe Roman, Jeanette Orbegozo, Cristina Rivera, Jan Kreuze, Fernando Serna, Soledad Gamboa, Willmer Perez, Victor Suarez, Greg Forbes, Marc Ghislain
    Abstract:

    One of the most efficient options for the control of late blight disease in potato (Solanum tuberosum) is the development of resistant varieties to Phytophthora infestans mediated by the direct transfer of resistance (R) genes through genetic engineering. In the present work, we used Solanum Bulbocastanum RB gene to confers broad spectrum resistance to P. infestans races. To that end, Agrobacterium - mediated genetic transformation was used to transform a susceptible potato variety, Desiree, with the binary vector pCIP68 harboring the RB gene. As a result, 19 transformed plants containing the RB gene were obtained. kanamycin resistance test and polymerase chain reaction (PCR) assays confirmed the integration of the T-DNA in the potato genome. The 19 transformed plants, also called transgenic events were subjected to infection under biosafety greenhouse conditions. Phytophthora infestans isolate POX067 of the EC-1 clonal lineage, commonly find in Peru, was used for the infection. Three of the 19 plants ([RB]54, [RB]56 and [RB]70) show high resistance levels to isolate POX067 of P. infestans