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Jiming Jiang - One of the best experts on this subject based on the ideXlab platform.
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constitutively expressed rb gene confers a high level but unreguLated resistance to potato Late Blight
American Journal of Potato Research, 2018Co-Authors: S M Wielgus, Jiming Jiang, Pudota B Bhaskar, Saowapa DuangpanAbstract: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.
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Marker-Assisted Selection for the Broad-Spectrum Potato Late Blight Resistance Conferred by Gene RB Derived from a Wild Potato Species
2014Co-Authors: Lara M. Colton, S M Wielgus, Horia I. Groza, Jiming JiangAbstract:Potato (Solanum tuberosumL.) Late Blight, caused byPhytophthora infestans (Mont.) de Bary, is one of the most damaging diseases in any crop. Deployment of resistant varieties is the most effective way to control this disease. However, breeding for Late Blight resistance has been a challenge because the race-specific resistance genes intro-gressed from wild potato S. demissum Lindl. have been short lived and breeding for ‘‘horizontal’ ’ or durable resistance has achieved only moderate successes. We previously demonstrated that the high-level Late Blight resistance in a wild potato relative, S. bulbocastanum Dunal subsp. bulbocastanum, is mainly controlled by a single resis-tance gene RB. Transgenic potato lines containing the RB gene have showed strong Late Blight resistance, comparable to the backcrossed progenies derived from the somatic hybrids between potato and S. bulbocastanum. Here we report the development of a polymeras
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correlation between transcript abundance of the rb gene and the level of the rb mediated Late Blight resistance in potato
Molecular Plant-microbe Interactions, 2009Co-Authors: Lara C Kramer, S M Wielgus, Mallory J Choudoir, Pudota B Bhaskar, Jiming JiangAbstract: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.
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performance of transgenic potato containing the Late Blight resistance gene rb
Plant Disease, 2008Co-Authors: Dennis Halterman, S M Wielgus, Lara C Kramer, Jiming JiangAbstract: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.
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sgt1 but not rar1 is essential for the rb mediated broad spectrum resistance to potato Late Blight
BMC Plant Biology, 2008Co-Authors: Pudota B Bhaskar, S M Wielgus, John A Raasch, Sandra Austinphillips, Lara C Kramer, Pavel Neumann, Jiming JiangAbstract: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.
S M Wielgus - One of the best experts on this subject based on the ideXlab platform.
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constitutively expressed rb gene confers a high level but unreguLated resistance to potato Late Blight
American Journal of Potato Research, 2018Co-Authors: S M Wielgus, Jiming Jiang, Pudota B Bhaskar, Saowapa DuangpanAbstract: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.
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Marker-Assisted Selection for the Broad-Spectrum Potato Late Blight Resistance Conferred by Gene RB Derived from a Wild Potato Species
2014Co-Authors: Lara M. Colton, S M Wielgus, Horia I. Groza, Jiming JiangAbstract:Potato (Solanum tuberosumL.) Late Blight, caused byPhytophthora infestans (Mont.) de Bary, is one of the most damaging diseases in any crop. Deployment of resistant varieties is the most effective way to control this disease. However, breeding for Late Blight resistance has been a challenge because the race-specific resistance genes intro-gressed from wild potato S. demissum Lindl. have been short lived and breeding for ‘‘horizontal’ ’ or durable resistance has achieved only moderate successes. We previously demonstrated that the high-level Late Blight resistance in a wild potato relative, S. bulbocastanum Dunal subsp. bulbocastanum, is mainly controlled by a single resis-tance gene RB. Transgenic potato lines containing the RB gene have showed strong Late Blight resistance, comparable to the backcrossed progenies derived from the somatic hybrids between potato and S. bulbocastanum. Here we report the development of a polymeras
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correlation between transcript abundance of the rb gene and the level of the rb mediated Late Blight resistance in potato
Molecular Plant-microbe Interactions, 2009Co-Authors: Lara C Kramer, S M Wielgus, Mallory J Choudoir, Pudota B Bhaskar, Jiming JiangAbstract: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.
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performance of transgenic potato containing the Late Blight resistance gene rb
Plant Disease, 2008Co-Authors: Dennis Halterman, S M Wielgus, Lara C Kramer, Jiming JiangAbstract: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.
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sgt1 but not rar1 is essential for the rb mediated broad spectrum resistance to potato Late Blight
BMC Plant Biology, 2008Co-Authors: Pudota B Bhaskar, S M Wielgus, John A Raasch, Sandra Austinphillips, Lara C Kramer, Pavel Neumann, Jiming JiangAbstract: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.
Lara C Kramer - One of the best experts on this subject based on the ideXlab platform.
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correlation between transcript abundance of the rb gene and the level of the rb mediated Late Blight resistance in potato
Molecular Plant-microbe Interactions, 2009Co-Authors: Lara C Kramer, S M Wielgus, Mallory J Choudoir, Pudota B Bhaskar, Jiming JiangAbstract: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.
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performance of transgenic potato containing the Late Blight resistance gene rb
Plant Disease, 2008Co-Authors: Dennis Halterman, S M Wielgus, Lara C Kramer, Jiming JiangAbstract: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.
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sgt1 but not rar1 is essential for the rb mediated broad spectrum resistance to potato Late Blight
BMC Plant Biology, 2008Co-Authors: Pudota B Bhaskar, S M Wielgus, John A Raasch, Sandra Austinphillips, Lara C Kramer, Pavel Neumann, Jiming JiangAbstract: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.
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sgt1 but not rar1 is essential for the rb mediated broad spectrum resistance to potato Late Blight
BMC Plant Biology, 2008Co-Authors: Pudota B Bhaskar, S M Wielgus, John A Raasch, Sandra Austinphillips, Lara C Kramer, Pavel Neumann, Jiming JiangAbstract:Background 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.
Pudota B Bhaskar - One of the best experts on this subject based on the ideXlab platform.
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constitutively expressed rb gene confers a high level but unreguLated resistance to potato Late Blight
American Journal of Potato Research, 2018Co-Authors: S M Wielgus, Jiming Jiang, Pudota B Bhaskar, Saowapa DuangpanAbstract: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.
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correlation between transcript abundance of the rb gene and the level of the rb mediated Late Blight resistance in potato
Molecular Plant-microbe Interactions, 2009Co-Authors: Lara C Kramer, S M Wielgus, Mallory J Choudoir, Pudota B Bhaskar, Jiming JiangAbstract: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.
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sgt1 but not rar1 is essential for the rb mediated broad spectrum resistance to potato Late Blight
BMC Plant Biology, 2008Co-Authors: Pudota B Bhaskar, S M Wielgus, John A Raasch, Sandra Austinphillips, Lara C Kramer, Pavel Neumann, Jiming JiangAbstract: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.
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sgt1 but not rar1 is essential for the rb mediated broad spectrum resistance to potato Late Blight
BMC Plant Biology, 2008Co-Authors: Pudota B Bhaskar, S M Wielgus, John A Raasch, Sandra Austinphillips, Lara C Kramer, Pavel Neumann, Jiming JiangAbstract:Background 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.
Richard G F Visser - One of the best experts on this subject based on the ideXlab platform.
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Silencing of six susceptibility genes results in potato Late Blight resistance
Transgenic Research, 2016Co-Authors: Kaile Sun, Jack H. Vossen, Richard G F Visser, Evert Jacobsen, Anne-marie A. Wolters, Maarten E. Rouwet, Annelies E. H. M. Loonen, Yuling BaiAbstract: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 Desiree, which is highly susceptible to Late Blight. The silencing of five genes resulted in complete resistance to the P. infestans isoLate Pic99189, and the silencing of a sixth S -gene resulted in reduced susceptibility. The application of S -genes to potato breeding for resistance to Late Blight is further discussed.
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The Solanum demissum R8 Late Blight resistance gene is an Sw-5 homologue that has been deployed worldwide in Late Blight resistant varieties.
Theoretical and Applied Genetics, 2016Co-Authors: Jack H. Vossen, Marjan Bergervoet, Gert Van Arkel, Kwang-ryong Jo, Evert Jacobsen, Richard G F VisserAbstract:Key message The potato Late Blight resistance geneR8has been cloned.R8is found in five Late Blight resistant varieties deployed in three different continents. R8 recognises Avr8 and is homologous to the NB-LRR protein Sw-5 from tomato.
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durable Late Blight resistance in potato through dynamic varieties obtained by cisgenesis
Potato Research, 2016Co-Authors: A J Haverkort, Piet M. Boonekamp, G J T Kessel, Jack H. Vossen, E Jacobsen, Ronald C B Hutten, L A P Lotz, Richard G F VisserAbstract:From 2006 through 2015, a research project on Durable Resistance in potato against Phytophthora (DuRPh) was carried out at Wageningen University and Research Centre. Its objective was to develop a proof of principle for durable resistance against Late Blight by cisgenesis. This public-funded project aimed at stimulating research on genetic modification and public debate on innovative genetic techniques. It was decided to clone and transfer Late Blight resistance (R) genes of crossable wild potato species (cisgenes) by Agrobacterium tumefaciens-mediated transformation without non-potato genes. A stack of multiple R genes were planned to be inserted into established varieties, thereby creating a dynamic variety in which the composition of the stacks may vary over space and time. Cisgenic plants were selected based on the expression of all inserted R genes and trueness-to-type. Within the project, 13 R genes from wild potato species were genetically mapped and three of them were cloned. Four varieties were transformed with one to three R genes. This was initially done using kanamycin resistance provided by a selectable marker gene of synthetic origin in order to quickly test the performance and stability of the introduced R genes and stacked R gene combinations. Once the functioning thereof was confirmed, marker-free transformations were conducted; thus, true cisgenic events were selected. The results about the different R genes, their chromosomal location, their specificity, the background dependence, the maximum size of a stack, its regeneration time and associated somaclonal variation frequency and its stability were studied. After selection and characterisation in the laboratory, the best cisgenic events were assessed in field trials for Late Blight resistance. This showed that inserted R genes were capable of turning a susceptible variety into a resistant one. Maximising longevity of the resistance was assured through resistance management research. It was shown that stacking of multiple R genes and monitoring how to deploy these stacks spatially and temporally could reduce fungicide use by over 80%. Communications through media and field demonstrations were manifold to allow public and policymakers to decide if cisgenesis is an acceptable tool to make potato farming more sustainable. Future deployment of the DuRPh strategy will depend largely on its status as a genetically modified crop or its exemption thereof. Worldwide near eradication of Late Blight would increase global annual potato production by close to 80 million tons, thereby contributing considerably to the needed additional global future food supply.
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towards sustainable potato Late Blight resistance by cisgenic r gene pyramiding
Plant Pathogen Resistance Biotechnology, 2016Co-Authors: Suxian Zhu, G J T Kessel, E Jacobsen, Richard G F Visser, Vivianne G A A Vleeshouwers, Yuling Bai, R C B Hutten, Jacobus Hubertus VossenAbstract:This chapter provides an overview of the possibilities of genetic modification (GM) potato breeding in general and specifically to combat the most important disease, Late Blight. Potato plants are vulnerable to a number of pests and diseases. An enigmatic question concerns whether individual Rpi genes can confer sufficient broad-spectrum resistance to impart durability. The presence of Rpi genes or transcripts as determined using molecular markers does not warrant their functional expression. Late Blight resistance resources from crossable species can be deployed for intragenic or cisgenic breeding strategies. The chapter presents and discusses a pipeline for cisgenic Late Blight resistance breeding that was developed at Wageningen UR Plant Breeding. If only two Rpi genes are present, often isoLates can be identified that overcome recognition mediated by one Rpi gene but not by the other. The Late Blight-resistant GM potato which was probably closest to commercialization was “Fortuna”.
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development of Late Blight resistant potatoes by cisgene stacking
BMC Biotechnology, 2014Co-Authors: Choljun Kim, E Jacobsen, Richard G F Visser, Sungjin Kim, Tokyong Kim, Marjan Bergervoet, Maarten A Jongsma, Jack H. VossenAbstract:Phytophthora infestans, causing Late Blight in potato, remains one of the most devastating pathogens in potato production and Late Blight resistance is a top priority in potato breeding. The introduction of multiple resistance (R) genes with different spectra from crossable species into potato varieties is required. Cisgenesis is a promising approach that introduces native genes from the crops own gene pool using GM technology, thereby retaining favourable characteristics of established varieties. We pursued a cisgenesis approach to introduce two broad spectrum potato Late Blight R genes, Rpi-sto1 and Rpi-vnt1.1 from the crossable species Solanum stoloniferum and Solanum venturii, respectively, into three different potato varieties. First, single R gene-containing transgenic plants were produced for all varieties to be used as references for the resistance levels and spectra to be expected in the respective genetic backgrounds. Next, a construct containing both cisgenic Late Blight R genes (Rpi-vnt1.1 and Rpi-sto1), but lacking the bacterial kanamycin resistance selection marker (NPTII) was transformed to the three selected potato varieties using Agrobacterium-mediated transformation. Gene transfer events were selected by PCR among regenerated shoots. Through further analyses involving morphological evaluations in the greenhouse, responsiveness to Avr genes and Late Blight resistance in detached leaf assays, the selection was narrowed down to eight independent events. These cisgenic events were selected because they showed broad spectrum Late Blight resistance due to the activity of both introduced R genes. The marker-free transformation was compared to kanamycin resistance assisted transformation in terms of T-DNA and vector backbone integration frequency. Also, differences in regeneration time and genotype dependency were evaluated. We developed a marker-free transformation pipeline to select potato plants functionally expressing a stack of Late Blight R genes. Marker-free transformation is less genotype dependent and less prone to vector backbone integration as compared to marker-assisted transformation. Thereby, this study provides an important tool for the successful deployment of R genes in agriculture and contributes to the production of potentially durable Late Blight resistant potatoes.
