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Sample records for phytophthora infestans effectors

  1. Molecular determinants of resistance activation and suppression by Phytophthora infestans effector IPI-O

    Science.gov (United States)

    The potato late blight pathogen, Phytophthora infestans, is able to rapidly evolve to overcome resistance genes. The pathogen accomplishes this by secreting an arsenal of proteins, termed effectors, that function to modify host cells. Although hundreds of candidate effectors have been identified in ...

  2. Multiple recognition of RXLR effectors is associated with nonhost resistance of pepper against Phytophthora infestans.

    Science.gov (United States)

    Lee, Hyun-Ah; Kim, Shin-Young; Oh, Sang-Keun; Yeom, Seon-In; Kim, Saet-Byul; Kim, Myung-Shin; Kamoun, Sophien; Choi, Doil

    2014-08-01

    Nonhost resistance (NHR) is a plant immune response to resist most pathogens. The molecular basis of NHR is poorly understood, but recognition of pathogen effectors by immune receptors, a response known as effector-triggered immunity, has been proposed as a component of NHR. We performed transient expression of 54 Phytophthora infestansRXLR effectors in pepper (Capsicum annuum) accessions. We used optimized heterologous expression methods and analyzed the inheritance of effector-induced cell death in an F2 population derived from a cross between two pepper accessions. Pepper showed a localized cell death response upon inoculation with P. infestans, suggesting that recognition of effectors may contribute to NHR in this system. Pepper accessions recognized as many as 36 effectors. Among the effectors, PexRD8 and Avrblb2 induced cell death in a broad range of pepper accessions. Segregation of effector-induced cell death in an F2 population derived from a cross between two pepper accessions fit 15:1, 9:7 or 3:1 ratios, depending on the effector. Our genetic data suggest that a single or two independent/complementary dominant genes are involved in the recognition of RXLR effectors. Multiple loci recognizing a series of effectors may underpin NHR of pepper to P. infestans and confer resistance durability.

  3. Multiple recognition of RXLR effectors is associated with nonhost resistance of pepper against Phytophthora infestans

    Science.gov (United States)

    Lee, Hyun-Ah; Kim, Shin-Young; Oh, Sang-Keun; Yeom, Seon-In; Kim, Saet-Byul; Kim, Myung-Shin; Kamoun, Sophien; Choi, Doil

    2014-01-01

    Nonhost resistance (NHR) is a plant immune response to resist most pathogens. The molecular basis of NHR is poorly understood, but recognition of pathogen effectors by immune receptors, a response known as effector-triggered immunity, has been proposed as a component of NHR. We performed transient expression of 54 Phytophthora infestansRXLR effectors in pepper (Capsicum annuum) accessions. We used optimized heterologous expression methods and analyzed the inheritance of effector-induced cell death in an F2 population derived from a cross between two pepper accessions. Pepper showed a localized cell death response upon inoculation with P. infestans, suggesting that recognition of effectors may contribute to NHR in this system. Pepper accessions recognized as many as 36 effectors. Among the effectors, PexRD8 and Avrblb2 induced cell death in a broad range of pepper accessions. Segregation of effector-induced cell death in an F2 population derived from a cross between two pepper accessions fit 15 : 1, 9 : 7 or 3 : 1 ratios, depending on the effector. Our genetic data suggest that a single or two independent/complementary dominant genes are involved in the recognition of RXLR effectors. Multiple loci recognizing a series of effectors may underpin NHR of pepper to P. infestans and confer resistance durability. PMID:24889686

  4. Phytophthora infestans effector AVRblb2 prevents secretion of a plant immune protease at the haustorial interface

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    Bozkurt, Tolga O.; Schornack, Sebastian; Win, Joe; Shindo, Takayuki; Ilyas, Muhammad; Oliva, Ricardo; Cano, Liliana M.; Jones, Alexandra M. E.; Huitema, Edgar; van der Hoorn, Renier A. L.; Kamoun, Sophien

    2011-01-01

    In response to pathogen attack, plant cells secrete antimicrobial molecules at the site of infection. However, how plant pathogens interfere with defense-related focal secretion remains poorly known. Here we show that the host-translocated RXLR-type effector protein AVRblb2 of the Irish potato famine pathogen Phytophthora infestans focally accumulates around haustoria, specialized infection structures that form inside plant cells, and promotes virulence by interfering with the execution of host defenses. AVRblb2 significantly enhances susceptibility of host plants to P. infestans by targeting the host papain-like cysteine protease C14 and specifically preventing its secretion into the apoplast. Plants altered in C14 expression were significantly affected in susceptibility to P. infestans in a manner consistent with a positive role of C14 in plant immunity. Our findings point to a unique counterdefense strategy that plant pathogens use to neutralize secreted host defense proteases. Effectors, such as AVRblb2, can be used as molecular probes to dissect focal immune responses at pathogen penetration sites. PMID:22143776

  5. Competitive Interaction Between Phytophthora Infestans Effectors Leads to Increased Aggressiveness on Plants Containing Broad-spectrum Late Blight Resistance

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    The resistance (R) gene RB confers broad-spectrum resistance to potato late blight and belongs. The RB protein recognizes the presence of members of the Phytophthora infestans effector family IPI-O to elicit resistance. Most isolates of the pathogen contain IPI-O variants that are recognized by R...

  6. Effector genomics accelerates discovery and functional profiling of potato disease resistance and phytophthora infestans avirulence genes.

    Directory of Open Access Journals (Sweden)

    Vivianne G A A Vleeshouwers

    Full Text Available Potato is the world's fourth largest food crop yet it continues to endure late blight, a devastating disease caused by the Irish famine pathogen Phytophthora infestans. Breeding broad-spectrum disease resistance (R genes into potato (Solanum tuberosum is the best strategy for genetically managing late blight but current approaches are slow and inefficient. We used a repertoire of effector genes predicted computationally from the P. infestans genome to accelerate the identification, functional characterization, and cloning of potentially broad-spectrum R genes. An initial set of 54 effectors containing a signal peptide and a RXLR motif was profiled for activation of innate immunity (avirulence or Avr activity on wild Solanum species and tentative Avr candidates were identified. The RXLR effector family IpiO induced hypersensitive responses (HR in S. stoloniferum, S. papita and the more distantly related S. bulbocastanum, the source of the R gene Rpi-blb1. Genetic studies with S. stoloniferum showed cosegregation of resistance to P. infestans and response to IpiO. Transient co-expression of IpiO with Rpi-blb1 in a heterologous Nicotiana benthamiana system identified IpiO as Avr-blb1. A candidate gene approach led to the rapid cloning of S. stoloniferum Rpi-sto1 and S. papita Rpi-pta1, which are functionally equivalent to Rpi-blb1. Our findings indicate that effector genomics enables discovery and functional profiling of late blight R genes and Avr genes at an unprecedented rate and promises to accelerate the engineering of late blight resistant potato varieties.

  7. A Phytophthora infestans RXLR effector targets plant PP1c isoforms that promote late blight disease.

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    Boevink, Petra C; Wang, Xiaodan; McLellan, Hazel; He, Qin; Naqvi, Shaista; Armstrong, Miles R; Zhang, Wei; Hein, Ingo; Gilroy, Eleanor M; Tian, Zhendong; Birch, Paul R J

    2016-01-29

    Plant pathogens deliver effectors to alter host processes. Knowledge of how effectors target and manipulate host proteins is critical to understand crop disease. Here, we show that in planta expression of the RXLR effector Pi04314 enhances leaf colonization by Phytophthora infestans via activity in the host nucleus and attenuates induction of jasmonic and salicylic acid-responsive genes. Pi04314 interacts with three host protein phosphatase 1 catalytic (PP1c) isoforms, causing their re-localization from the nucleolus to the nucleoplasm. Re-localization of PP1c-1 also occurs during infection and is dependent on an R/KVxF motif in the effector. Silencing the PP1c isoforms or overexpression of a phosphatase-dead PP1c-1 mutant attenuates infection, demonstrating that host PP1c activity is required for disease. Moreover, expression of PP1c-1mut abolishes enhanced leaf colonization mediated by in planta Pi04314 expression. We argue that PP1c isoforms are susceptibility factors forming holoenzymes with Pi04314 to promote late blight disease.

  8. The Cell Death Triggered by the Nuclear Localized RxLR Effector PITG_22798 from Phytophthora infestans Is Suppressed by the Effector AVR3b.

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    Wang, Hongyang; Ren, Yajuan; Zhou, Jing; Du, Juan; Hou, Juan; Jiang, Rui; Wang, Haixia; Tian, Zhendong; Xie, Conghua

    2017-02-14

    Phytopathogenic oomycetes, such as Phytophthora infestans, potentially secrete many RxLR effector proteins into plant cells to modulate plant immune responses and promote colonization. However, the molecular mechanisms by which these RxLR effectors suppress plant immune responses are largely unknown. Here we describe an RxLR effector PITG_22798 (Gene accession: XM_002998349) that was upregulated during early infection of potato by P. infestans. By employment of agroinfiltration, we observed that PITG_22798 triggers cell death in Nicotiana benthamiana. Confocal microscopic examination showed that PITG_22798-GFP (Green Fluorescent Protein) located in the host nucleus when expressed transiently in N. benthamiana leaves. A nuclear localization signal (NLS) domain of PITG_22798 is important for nuclear localization and cell death-inducing activity. Sequence alignment and transient expression showed that PITG_22798 from diverse P. infestans isolates are conserved, and transient expression of PITG_22798 enhances P. infestans colonization of N. benthamiana leaves, which suggests that PITG_22798 contributes to P. infestans infection. PITG_22798-triggered cell death is dependent on SGT1-mediated signaling and is suppressed by the P. infestans avirulence effector 3b (AVR3b). The present research provides a clue for further investigation of how P. infestans effector PITG_22798 associates with and modulates host immunity.

  9. Phytophthora infestans RXLR effector PexRD2 interacts with host MAPKKK ε to suppress plant immune signaling.

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    King, Stuart R F; McLellan, Hazel; Boevink, Petra C; Armstrong, Miles R; Bukharova, Tatyana; Sukarta, Octavina; Win, Joe; Kamoun, Sophien; Birch, Paul R J; Banfield, Mark J

    2014-03-01

    Mitogen-activated protein kinase cascades are key players in plant immune signaling pathways, transducing the perception of invading pathogens into effective defense responses. Plant pathogenic oomycetes, such as the Irish potato famine pathogen Phytophthora infestans, deliver RXLR effector proteins to plant cells to modulate host immune signaling and promote colonization. Our understanding of the molecular mechanisms by which these effectors act in plant cells is limited. Here, we report that the P. infestans RXLR effector PexRD2 interacts with the kinase domain of MAPKKKε, a positive regulator of cell death associated with plant immunity. Expression of PexRD2 or silencing MAPKKKε in Nicotiana benthamiana enhances susceptibility to P. infestans. We show that PexRD2 perturbs signaling pathways triggered by or dependent on MAPKKKε. By contrast, homologs of PexRD2 from P. infestans had reduced or no interaction with MAPKKKε and did not promote disease susceptibility. Structure-led mutagenesis identified PexRD2 variants that do not interact with MAPKKKε and fail to support enhanced pathogen growth or perturb MAPKKKε signaling pathways. Our findings provide evidence that P. infestans RXLR effector PexRD2 has evolved to interact with a specific host MAPKKK to perturb plant immunity-related signaling.

  10. Phytophthora infestans RXLR Effector PexRD2 Interacts with Host MAPKKKε to Suppress Plant Immune Signaling[W][OPEN

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    King, Stuart R.F.; McLellan, Hazel; Boevink, Petra C.; Armstrong, Miles R.; Bukharova, Tatyana; Sukarta, Octavina; Win, Joe; Kamoun, Sophien; Birch, Paul R.J.; Banfield, Mark J.

    2014-01-01

    Mitogen-activated protein kinase cascades are key players in plant immune signaling pathways, transducing the perception of invading pathogens into effective defense responses. Plant pathogenic oomycetes, such as the Irish potato famine pathogen Phytophthora infestans, deliver RXLR effector proteins to plant cells to modulate host immune signaling and promote colonization. Our understanding of the molecular mechanisms by which these effectors act in plant cells is limited. Here, we report that the P. infestans RXLR effector PexRD2 interacts with the kinase domain of MAPKKKε, a positive regulator of cell death associated with plant immunity. Expression of PexRD2 or silencing MAPKKKε in Nicotiana benthamiana enhances susceptibility to P. infestans. We show that PexRD2 perturbs signaling pathways triggered by or dependent on MAPKKKε. By contrast, homologs of PexRD2 from P. infestans had reduced or no interaction with MAPKKKε and did not promote disease susceptibility. Structure-led mutagenesis identified PexRD2 variants that do not interact with MAPKKKε and fail to support enhanced pathogen growth or perturb MAPKKKε signaling pathways. Our findings provide evidence that P. infestans RXLR effector PexRD2 has evolved to interact with a specific host MAPKKK to perturb plant immunity–related signaling. PMID:24632534

  11. Functionally redundant RXLR effectors from Phytophthora infestans act at different steps to suppress early flg22-triggered immunity.

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    Zheng, Xiangzi; McLellan, Hazel; Fraiture, Malou; Liu, Xiaoyu; Boevink, Petra C; Gilroy, Eleanor M; Chen, Ying; Kandel, Kabindra; Sessa, Guido; Birch, Paul R J; Brunner, Frédéric

    2014-04-01

    Genome sequences of several economically important phytopathogenic oomycetes have revealed the presence of large families of so-called RXLR effectors. Functional screens have identified RXLR effector repertoires that either compromise or induce plant defense responses. However, limited information is available about the molecular mechanisms underlying the modes of action of these effectors in planta. The perception of highly conserved pathogen- or microbe-associated molecular patterns (PAMPs/MAMPs), such as flg22, triggers converging signaling pathways recruiting MAP kinase cascades and inducing transcriptional re-programming, yielding a generic anti-microbial response. We used a highly synchronizable, pathogen-free protoplast-based assay to identify a set of RXLR effectors from Phytophthora infestans (PiRXLRs), the causal agent of potato and tomato light blight that manipulate early stages of flg22-triggered signaling. Of thirty-three tested PiRXLR effector candidates, eight, called Suppressor of early Flg22-induced Immune response (SFI), significantly suppressed flg22-dependent activation of a reporter gene under control of a typical MAMP-inducible promoter (pFRK1-Luc) in tomato protoplasts. We extended our analysis to Arabidopsis thaliana, a non-host plant species of P. infestans. From the aforementioned eight SFI effectors, three appeared to share similar functions in both Arabidopsis and tomato by suppressing transcriptional activation of flg22-induced marker genes downstream of post-translational MAP kinase activation. A further three effectors interfere with MAMP signaling at, or upstream of, the MAP kinase cascade in tomato, but not in Arabidopsis. Transient expression of the SFI effectors in Nicotiana benthamiana enhances susceptibility to P. infestans and, for the most potent effector, SFI1, nuclear localization is required for both suppression of MAMP signaling and virulence function. The present study provides a framework to decipher the molecular

  12. Functionally redundant RXLR effectors from Phytophthora infestans act at different steps to suppress early flg22-triggered immunity.

    Directory of Open Access Journals (Sweden)

    Xiangzi Zheng

    2014-04-01

    Full Text Available Genome sequences of several economically important phytopathogenic oomycetes have revealed the presence of large families of so-called RXLR effectors. Functional screens have identified RXLR effector repertoires that either compromise or induce plant defense responses. However, limited information is available about the molecular mechanisms underlying the modes of action of these effectors in planta. The perception of highly conserved pathogen- or microbe-associated molecular patterns (PAMPs/MAMPs, such as flg22, triggers converging signaling pathways recruiting MAP kinase cascades and inducing transcriptional re-programming, yielding a generic anti-microbial response. We used a highly synchronizable, pathogen-free protoplast-based assay to identify a set of RXLR effectors from Phytophthora infestans (PiRXLRs, the causal agent of potato and tomato light blight that manipulate early stages of flg22-triggered signaling. Of thirty-three tested PiRXLR effector candidates, eight, called Suppressor of early Flg22-induced Immune response (SFI, significantly suppressed flg22-dependent activation of a reporter gene under control of a typical MAMP-inducible promoter (pFRK1-Luc in tomato protoplasts. We extended our analysis to Arabidopsis thaliana, a non-host plant species of P. infestans. From the aforementioned eight SFI effectors, three appeared to share similar functions in both Arabidopsis and tomato by suppressing transcriptional activation of flg22-induced marker genes downstream of post-translational MAP kinase activation. A further three effectors interfere with MAMP signaling at, or upstream of, the MAP kinase cascade in tomato, but not in Arabidopsis. Transient expression of the SFI effectors in Nicotiana benthamiana enhances susceptibility to P. infestans and, for the most potent effector, SFI1, nuclear localization is required for both suppression of MAMP signaling and virulence function. The present study provides a framework to decipher the

  13. Competition between Phytophthora infestans effectors leads to increased aggressiveness on plants containing broad-spectrum late blight resistance.

    Directory of Open Access Journals (Sweden)

    Dennis A Halterman

    Full Text Available BACKGROUND: The destructive plant disease potato late blight is caused by the oomycete pathogen Phytophthora infestans (Mont. de Bary. This disease has remained particularly problematic despite intensive breeding efforts to integrate resistance into cultivated potato, largely because of the pathogen's ability to quickly evolve to overcome major resistance genes. The RB gene, identified in the wild potato species S. bulbocastanum, encodes a protein that confers broad-spectrum resistance to most P. infestans isolates through its recognition of highly conserved members of the corresponding pathogen effector family IPI-O. IpiO is a multigene family of effectors and while the majority of IPI-O proteins are recognized by RB to elicit host resistance, some variants exist that are able to elude detection (e.g. IPI-O4. METHODS AND FINDINGS: In the present study, analysis of ipiO variants among 40 different P. infestans isolates collected from Guatemala, Thailand, and the United States revealed a high degree of complexity within this gene family. Isolate aggressiveness was correlated with increased ipiO diversity and especially the presence of the ipiO4 variant. Furthermore, isolates expressing IPI-O4 overcame RB-mediated resistance in transgenic potato plants even when the resistance-eliciting IPI-O1 variant was present. In support of this finding, we observed that expression of IPI-O4 via Agrobacterium blocked recognition of IPI-O1, leading to inactivation of RB-mediated programmed cell death in Nicotiana benthamiana. CONCLUSIONS: In this study we definitively demonstrate and provide the first evidence that P. infestans can defeat an R protein through inhibition of recognition of the corresponding effector protein.

  14. Phytophthora infestans Argonaute 1 binds microRNA and small RNAs from effector genes and transposable elements.

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    Åsman, Anna K M; Fogelqvist, Johan; Vetukuri, Ramesh R; Dixelius, Christina

    2016-08-01

    Phytophthora spp. encode large sets of effector proteins and distinct populations of small RNAs (sRNAs). Recent evidence has suggested that pathogen-derived sRNAs can modulate the expression of plant defense genes. Here, we studied the sRNA classes and functions associated with Phytophthora infestans Argonaute (Ago) proteins. sRNAs were co-immunoprecipitated with three PiAgo proteins and deep sequenced. Twenty- to twenty-two-nucleotide (nt) sRNAs were identified as the main interaction partners of PiAgo1 and high enrichment of 24-26-nt sRNAs was seen in the PiAgo4-bound sample. The frequencies and sizes of transposable element (TE)-derived sRNAs in the different PiAgo libraries suggested diversified roles of the PiAgo proteins in the control of different TE classes. We further provide evidence for the involvement of PiAgo1 in the P. infestans microRNA (miRNA) pathway. Protein-coding genes are probably regulated by the shared action of PiAgo1 and PiAgo5, as demonstrated by analysis of differential expression. An abundance of sRNAs from genes encoding host cell death-inducing Crinkler (CRN) effectors was bound to PiAgo1, implicating this protein in the regulation of the expanded CRN gene family. The data suggest that PiAgo1 plays an essential role in gene regulation and that at least two RNA silencing pathways regulate TEs in the plant-pathogenic oomycete P. infestans.

  15. Host protein BSL1 associates with Phytophthora infestans RXLR effector AVR2 and the Solanum demissum Immune receptor R2 to mediate disease resistance.

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    Saunders, Diane G O; Breen, Susan; Win, Joe; Schornack, Sebastian; Hein, Ingo; Bozkurt, Tolga O; Champouret, Nicolas; Vleeshouwers, Vivianne G A A; Birch, Paul R J; Gilroy, Eleanor M; Kamoun, Sophien

    2012-08-01

    Plant pathogens secrete effector proteins to modulate plant immunity and promote host colonization. Plant nucleotide binding leucine-rich repeat (NB-LRR) immunoreceptors recognize specific pathogen effectors directly or indirectly. Little is known about how NB-LRR proteins recognize effectors of filamentous plant pathogens, such as Phytophthora infestans. AVR2 belongs to a family of 13 sequence-divergent P. infestans RXLR effectors that are differentially recognized by members of the R2 NB-LRR family in Solanum demissum. We report that the putative plant phosphatase BSU-LIKE PROTEIN1 (BSL1) is required for R2-mediated perception of AVR2 and resistance to P. infestans. AVR2 associates with BSL1 and mediates the interaction of BSL1 with R2 in planta, possibly through the formation of a ternary complex. Strains of P. infestans that are virulent on R2 potatoes express an unrecognized form, Avr2-like (referred to as A2l). A2L can still interact with BSL1 but does not promote the association of BSL1 with R2. Our findings show that recognition of the P. infestans AVR2 effector by the NB-LRR protein R2 requires the putative phosphatase BSL1. This reveals that, similar to effectors of phytopathogenic bacteria, recognition of filamentous pathogen effectors can be mediated via a host protein that interacts with both the effector and the NB-LRR immunoreceptor.

  16. Host Protein BSL1 Associates with Phytophthora infestans RXLR Effector AVR2 and the Solanum demissum Immune Receptor R2 to Mediate Disease Resistance[C][W

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    Saunders, Diane G.O.; Breen, Susan; Win, Joe; Schornack, Sebastian; Hein, Ingo; Bozkurt, Tolga O.; Champouret, Nicolas; Vleeshouwers, Vivianne G.A.A.; Birch, Paul R.J.; Gilroy, Eleanor M.; Kamoun, Sophien

    2012-01-01

    Plant pathogens secrete effector proteins to modulate plant immunity and promote host colonization. Plant nucleotide binding leucine-rich repeat (NB-LRR) immunoreceptors recognize specific pathogen effectors directly or indirectly. Little is known about how NB-LRR proteins recognize effectors of filamentous plant pathogens, such as Phytophthora infestans. AVR2 belongs to a family of 13 sequence-divergent P. infestans RXLR effectors that are differentially recognized by members of the R2 NB-LRR family in Solanum demissum. We report that the putative plant phosphatase BSU-LIKE PROTEIN1 (BSL1) is required for R2-mediated perception of AVR2 and resistance to P. infestans. AVR2 associates with BSL1 and mediates the interaction of BSL1 with R2 in planta, possibly through the formation of a ternary complex. Strains of P. infestans that are virulent on R2 potatoes express an unrecognized form, Avr2-like (referred to as A2l). A2L can still interact with BSL1 but does not promote the association of BSL1 with R2. Our findings show that recognition of the P. infestans AVR2 effector by the NB-LRR protein R2 requires the putative phosphatase BSL1. This reveals that, similar to effectors of phytopathogenic bacteria, recognition of filamentous pathogen effectors can be mediated via a host protein that interacts with both the effector and the NB-LRR immunoreceptor. PMID:22885736

  17. A Recent Expansion of the RXLR Effector Gene Avrblb2 Is Maintained in Global Populations of Phytophthora infestans Indicating Different Contributions to Virulence.

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    Oliva, Ricardo F; Cano, Liliana M; Raffaele, Sylvain; Win, Joe; Bozkurt, Tolga O; Belhaj, Khaoula; Oh, Sang-Keun; Thines, Marco; Kamoun, Sophien

    2015-08-01

    The introgression of disease resistance (R) genes encoding immunoreceptors with broad-spectrum recognition into cultivated potato appears to be the most promising approach to achieve sustainable management of late blight caused by the oomycete pathogen Phytophthora infestans. Rpi-blb2 from Solanum bulbocastanum shows great potential for use in agriculture based on preliminary potato disease trials. Rpi-blb2 confers immunity by recognizing the P. infestans avirulence effector protein AVRblb2 after it is translocated inside the plant cell. This effector belongs to the RXLR class of effectors and is under strong positive selection. Structure-function analyses revealed a key polymorphic amino acid (position 69) in AVRblb2 effector that is critical for activation of Rpi-blb2. In this study, we reconstructed the evolutionary history of the Avrblb2 gene family and further characterized its genetic structure in worldwide populations. Our data indicate that Avrblb2 evolved as a single-copy gene in a putative ancestral species of P. infestans and has recently expanded in the Phytophthora spp. that infect solanaceous hosts. As a consequence, at least four variants of AVRblb2 arose in P. infestans. One of these variants, with a Phe residue at position 69, evades recognition by the cognate resistance gene. Surprisingly, all Avrblb2 variants are maintained in pathogen populations. This suggests a potential benefit for the pathogen in preserving duplicated versions of AVRblb2, possibly because the variants may have different contributions to pathogen fitness in a diversified solanaceous host environment.

  18. Host-mediated gene silencing of a single effector gene from the potato pathogen Phytophthora infestans imparts partial resistance to late blight disease.

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    Sanju, Suman; Siddappa, Sundaresha; Thakur, Aditi; Shukla, Pradeep K; Srivastava, Nidhi; Pattanayak, Debasis; Sharma, Sanjeev; Singh, B P

    2015-11-01

    RNA interference (RNAi) has proved a powerful genetic tool for silencing genes in plants. Host-induced gene silencing of pathogen genes has provided a gene knockout strategy for a wide range of biotechnological applications. The RXLR effector Avr3a gene is largely responsible for virulence of oomycete plant pathogen Phytophthora infestans. In this study, we attempted to silence the Avr3a gene of P. infestans through RNAi technology. The P. infestans inoculation resulted in lower disease progression and a reduction in pathogen load, as demonstrated by disease scoring and quantification of pathogen biomass in terms of Pi08 repetitive elements, respectively. Transgenic plants induced moderate silencing of Avr3a, and the presence and/or expression of small interfering RNAs, as determined through Northern hybridization, indicated siRNA targeted against Avr3a conferred moderate resistance to P. infestans. The single effector gene did not provide complete resistance against P. infestans. Although the Avr3a effector gene could confer moderate resistance, for complete resistance, the cumulative effect of effector genes in addition to Avr3a needs to be considered. In this study, we demonstrated that host-induced RNAi is an effective strategy for functional genomics in oomycetes.

  19. Determination of virulence contributions from Phytophthora infestans effectors IPI-O1 and IPI-O4

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    Potato late blight, caused by the oomycete pathogen Phytophthora infestans, is one of the most destructive plant diseases. Despite decades of intensive breeding efforts, it remains a threat to potato production worldwide, in part because newly evolved pathogen isolates quickly overcome major resista...

  20. Competitive Between Phytophthora Infestans Effectors Leads to Increased Aggressiveness on Plants Containing Broad-Spectrum Late Blight Resistance

    Science.gov (United States)

    Potato late blight is a particularly destructive plant disease caused by the oomycete pathogen Phytophthora infestans (Mont.) de Bary. Late blight has remained particularly problematic despite intensive breeding efforts to integrate resistance into cultivated potato. This is due to the pathogen’s ab...

  1. An RxLR effector from Phytophthora infestans prevents re-localisation of two plant NAC transcription factors from the endoplasmic reticulum to the nucleus.

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    Hazel McLellan

    Full Text Available The potato late blight pathogen Phytophthora infestans secretes an array of effector proteins thought to act in its hosts by disarming defences and promoting pathogen colonisation. However, little is known about the host targets of these effectors and how they are manipulated by the pathogen. This work describes the identification of two putative membrane-associated NAC transcription factors (TF as the host targets of the RxLR effector PITG_03192 (Pi03192. The effector interacts with NAC Targeted by Phytophthora (NTP 1 and NTP2 at the endoplasmic reticulum (ER membrane, where these proteins are localised. Transcripts of NTP1 and NTP2 rapidly accumulate following treatment with culture filtrate (CF from in vitro grown P. infestans, which acts as a mixture of Phytophthora PAMPs and elicitors, but significantly decrease during P. infestans infection, indicating that pathogen activity may prevent their up-regulation. Silencing of NTP1 or NTP2 in the model host plant Nicotiana benthamiana increases susceptibility to P. infestans, whereas silencing of Pi03192 in P. infestans reduces pathogenicity. Transient expression of Pi03192 in planta restores pathogenicity of the Pi03192-silenced line. Moreover, colonisation by the Pi03192-silenced line is significantly enhanced on N. benthamiana plants in which either NTP1 or NTP2 have been silenced. StNTP1 and StNTP2 proteins are released from the ER membrane following treatment with P. infestans CF and accumulate in the nucleus, after which they are rapidly turned over by the 26S proteasome. In contrast, treatment with the defined PAMP flg22 fails to up-regulate NTP1 and NTP2, or promote re-localisation of their protein products to the nucleus, indicating that these events follow perception of a component of CF that appears to be independent of the FLS2/flg22 pathway. Importantly, Pi03192 prevents CF-triggered re-localisation of StNTP1 and StNTP2 from the ER into the nucleus, revealing a novel effector mode

  2. An RxLR effector from Phytophthora infestans prevents re-localisation of two plant NAC transcription factors from the endoplasmic reticulum to the nucleus.

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    McLellan, Hazel; Boevink, Petra C; Armstrong, Miles R; Pritchard, Leighton; Gomez, Sonia; Morales, Juan; Whisson, Stephen C; Beynon, Jim L; Birch, Paul R J

    2013-01-01

    The potato late blight pathogen Phytophthora infestans secretes an array of effector proteins thought to act in its hosts by disarming defences and promoting pathogen colonisation. However, little is known about the host targets of these effectors and how they are manipulated by the pathogen. This work describes the identification of two putative membrane-associated NAC transcription factors (TF) as the host targets of the RxLR effector PITG_03192 (Pi03192). The effector interacts with NAC Targeted by Phytophthora (NTP) 1 and NTP2 at the endoplasmic reticulum (ER) membrane, where these proteins are localised. Transcripts of NTP1 and NTP2 rapidly accumulate following treatment with culture filtrate (CF) from in vitro grown P. infestans, which acts as a mixture of Phytophthora PAMPs and elicitors, but significantly decrease during P. infestans infection, indicating that pathogen activity may prevent their up-regulation. Silencing of NTP1 or NTP2 in the model host plant Nicotiana benthamiana increases susceptibility to P. infestans, whereas silencing of Pi03192 in P. infestans reduces pathogenicity. Transient expression of Pi03192 in planta restores pathogenicity of the Pi03192-silenced line. Moreover, colonisation by the Pi03192-silenced line is significantly enhanced on N. benthamiana plants in which either NTP1 or NTP2 have been silenced. StNTP1 and StNTP2 proteins are released from the ER membrane following treatment with P. infestans CF and accumulate in the nucleus, after which they are rapidly turned over by the 26S proteasome. In contrast, treatment with the defined PAMP flg22 fails to up-regulate NTP1 and NTP2, or promote re-localisation of their protein products to the nucleus, indicating that these events follow perception of a component of CF that appears to be independent of the FLS2/flg22 pathway. Importantly, Pi03192 prevents CF-triggered re-localisation of StNTP1 and StNTP2 from the ER into the nucleus, revealing a novel effector mode-of-action to

  3. Silencing of the PiAvr3a effector-encoding gene from Phytophthora infestans by transcriptional fusion to a short interspersed element.

    Science.gov (United States)

    Vetukuri, Ramesh R; Tian, Zhendong; Avrova, Anna O; Savenkov, Eugene I; Dixelius, Christina; Whisson, Stephen C

    2011-12-01

    Phytophthora infestans is the notorious oomycete causing late blight of potato and tomato. A large proportion of the P. infestans genome is composed of transposable elements, the activity of which may be controlled by RNA silencing. Accumulation of small RNAs is one of the hallmarks of RNA silencing. Here we demonstrate the presence of small RNAs corresponding to the sequence of a short interspersed retrotransposable element (SINE) suggesting that small RNAs might be involved in silencing of SINEs in P. infestans. This notion was exploited to develop novel tools for gene silencing in P. infestans by engineering transcriptional fusions of the PiAvr3a gene, encoding an RXLR avirulence effector, to the infSINEm retroelement. Transgenic P. infestans lines expressing either 5'-infSINEm::PiAvr3a-3' or 5'-PiAvr3a::SINEm-3' chimeric transcripts initially exhibited partial silencing of PiAvr3a. Over time, PiAvr3a either recovered wild type transcript levels in some lines, or became fully silenced in others. Introduction of an inverted repeat construct was also successful in yielding P. infestans transgenic lines silenced for PiAvr3a. In contrast, constructs expressing antisense or aberrant RNA transcripts failed to initiate silencing of PiAvr3a. Lines exhibiting the most effective silencing of PiAvr3a were either weakly or non-pathogenic on susceptible potato cv. Bintje. This study expands the repertoire of reverse genetics tools available for P. infestans research, and provides insights into a possible mode of variation in effector expression through spread of silencing from adjacent retroelements.

  4. Quantitative label-free phosphoproteomics of six different life stages of the late blight pathogen Phytophthora infestans reveals abundant phosphorylation of members of the CRN effector family.

    Science.gov (United States)

    Resjö, Svante; Ali, Ashfaq; Meijer, Harold J G; Seidl, Michael F; Snel, Berend; Sandin, Marianne; Levander, Fredrik; Govers, Francine; Andreasson, Erik

    2014-04-04

    The oomycete Phytophthora infestans is the causal agent of late blight in potato and tomato. Since the underlying processes that govern pathogenicity and development in P. infestans are largely unknown, we have performed a large-scale phosphoproteomics study of six different P. infestans life stages. We have obtained quantitative data for 2922 phosphopeptides and compared their abundance. Life-stage-specific phosphopeptides include ATP-binding cassette transporters and a kinase that only occurs in appressoria. In an extended data set, we identified 2179 phosphorylation sites and deduced 22 phosphomotifs. Several of the phosphomotifs matched consensus sequences of kinases that occur in P. infestans but not Arabidopsis. In addition, we detected tyrosine phosphopeptides that are potential targets of kinases resembling mammalian tyrosine kinases. Among the phosphorylated proteins are members of the RXLR and Crinkler effector families. The latter are phosphorylated in several life stages and at multiple positions, in sites that are conserved between different members of the Crinkler family. This indicates that proteins in the Crinkler family have functions beyond their putative role as (necrosis-inducing) effectors. This phosphoproteomics data will be instrumental for studies on oomycetes and host-oomycete interactions. The data sets have been deposited to ProteomeXchange (identifier PXD000433).

  5. Phytophthora infestans, een dynamische ziekteverwekker

    NARCIS (Netherlands)

    Govers, F.

    2010-01-01

    Samenvatting van de inaugurele rede van Francine Govers op 11 juni 2009. Dit artikel beschrijft de stand van zaken in het onderzoek aan oömyceten en in het bijzonder aan Phytophthora infestans, de veroorzaker van de aardappelziekte. Er wordt ingegaan op ziektebestrijding en resistentieveredeling, de

  6. Using effectors of Phytophthora infestans to teach pathogenesis: Our attempt to provide a more comprehensive education

    Science.gov (United States)

    The topic of pathogenesis mechanisms (R/avirulence genes, effectors, and hypersensitive response) has proved challenging for students in our introductory plant pathology course. An apparent gap exists in the curriculum between this introductory course and higher level plant-microbe interaction cours...

  7. Phytophthora infestans RXLR-WY Effector AVR3a Associates with Dynamin-Related Protein 2 Required for Endocytosis of the Plant Pattern Recognition Receptor FLS2.

    Science.gov (United States)

    Chaparro-Garcia, Angela; Schwizer, Simon; Sklenar, Jan; Yoshida, Kentaro; Petre, Benjamin; Bos, Jorunn I B; Schornack, Sebastian; Jones, Alexandra M E; Bozkurt, Tolga O; Kamoun, Sophien

    2015-01-01

    Pathogens utilize effectors to suppress basal plant defense known as PTI (Pathogen-associated molecular pattern-triggered immunity). However, our knowledge of PTI suppression by filamentous plant pathogens, i.e. fungi and oomycetes, remains fragmentary. Previous work revealed that the co-receptor BAK1/SERK3 contributes to basal immunity against the potato pathogen Phytophthora infestans. Moreover BAK1/SERK3 is required for the cell death induced by P. infestans elicitin INF1, a protein with characteristics of PAMPs. The P. infestans host-translocated RXLR-WY effector AVR3a is known to supress INF1-mediated cell death by binding the plant E3 ligase CMPG1. In contrast, AVR3aKI-Y147del, a deletion mutant of the C-terminal tyrosine of AVR3a, fails to bind CMPG1 and does not suppress INF1-mediated cell death. Here, we studied the extent to which AVR3a and its variants perturb additional BAK1/SERK3-dependent PTI responses in N. benthamiana using the elicitor/receptor pair flg22/FLS2 as a model. We found that all tested variants of AVR3a suppress defense responses triggered by flg22 and reduce internalization of activated FLS2. Moreover, we discovered that AVR3a associates with the Dynamin-Related Protein 2 (DRP2), a plant GTPase implicated in receptor-mediated endocytosis. Interestingly, silencing of DRP2 impaired ligand-induced FLS2 internalization but did not affect internalization of the growth receptor BRI1. Our results suggest that AVR3a associates with a key cellular trafficking and membrane-remodeling complex involved in immune receptor-mediated endocytosis. We conclude that AVR3a is a multifunctional effector that can suppress BAK1/SERK3-mediated immunity through at least two different pathways.

  8. Phytophthora infestans RXLR-WY Effector AVR3a Associates with Dynamin-Related Protein 2 Required for Endocytosis of the Plant Pattern Recognition Receptor FLS2

    Science.gov (United States)

    Chaparro-Garcia, Angela; Schwizer, Simon; Sklenar, Jan; Yoshida, Kentaro; Petre, Benjamin; Bos, Jorunn I. B.; Schornack, Sebastian; Jones, Alexandra M. E.; Bozkurt, Tolga O.; Kamoun, Sophien

    2015-01-01

    Pathogens utilize effectors to suppress basal plant defense known as PTI (Pathogen-associated molecular pattern-triggered immunity). However, our knowledge of PTI suppression by filamentous plant pathogens, i.e. fungi and oomycetes, remains fragmentary. Previous work revealed that the co-receptor BAK1/SERK3 contributes to basal immunity against the potato pathogen Phytophthora infestans. Moreover BAK1/SERK3 is required for the cell death induced by P. infestans elicitin INF1, a protein with characteristics of PAMPs. The P. infestans host-translocated RXLR-WY effector AVR3a is known to supress INF1-mediated cell death by binding the plant E3 ligase CMPG1. In contrast, AVR3aKI-Y147del, a deletion mutant of the C-terminal tyrosine of AVR3a, fails to bind CMPG1 and does not suppress INF1-mediated cell death. Here, we studied the extent to which AVR3a and its variants perturb additional BAK1/SERK3-dependent PTI responses in N. benthamiana using the elicitor/receptor pair flg22/FLS2 as a model. We found that all tested variants of AVR3a suppress defense responses triggered by flg22 and reduce internalization of activated FLS2. Moreover, we discovered that AVR3a associates with the Dynamin-Related Protein 2 (DRP2), a plant GTPase implicated in receptor-mediated endocytosis. Interestingly, silencing of DRP2 impaired ligand-induced FLS2 internalization but did not affect internalization of the growth receptor BRI1. Our results suggest that AVR3a associates with a key cellular trafficking and membrane-remodeling complex involved in immune receptor-mediated endocytosis. We conclude that AVR3a is a multifunctional effector that can suppress BAK1/SERK3-mediated immunity through at least two different pathways. PMID:26348328

  9. Phytophthora infestans RXLR-WY Effector AVR3a Associates with Dynamin-Related Protein 2 Required for Endocytosis of the Plant Pattern Recognition Receptor FLS2.

    Directory of Open Access Journals (Sweden)

    Angela Chaparro-Garcia

    Full Text Available Pathogens utilize effectors to suppress basal plant defense known as PTI (Pathogen-associated molecular pattern-triggered immunity. However, our knowledge of PTI suppression by filamentous plant pathogens, i.e. fungi and oomycetes, remains fragmentary. Previous work revealed that the co-receptor BAK1/SERK3 contributes to basal immunity against the potato pathogen Phytophthora infestans. Moreover BAK1/SERK3 is required for the cell death induced by P. infestans elicitin INF1, a protein with characteristics of PAMPs. The P. infestans host-translocated RXLR-WY effector AVR3a is known to supress INF1-mediated cell death by binding the plant E3 ligase CMPG1. In contrast, AVR3aKI-Y147del, a deletion mutant of the C-terminal tyrosine of AVR3a, fails to bind CMPG1 and does not suppress INF1-mediated cell death. Here, we studied the extent to which AVR3a and its variants perturb additional BAK1/SERK3-dependent PTI responses in N. benthamiana using the elicitor/receptor pair flg22/FLS2 as a model. We found that all tested variants of AVR3a suppress defense responses triggered by flg22 and reduce internalization of activated FLS2. Moreover, we discovered that AVR3a associates with the Dynamin-Related Protein 2 (DRP2, a plant GTPase implicated in receptor-mediated endocytosis. Interestingly, silencing of DRP2 impaired ligand-induced FLS2 internalization but did not affect internalization of the growth receptor BRI1. Our results suggest that AVR3a associates with a key cellular trafficking and membrane-remodeling complex involved in immune receptor-mediated endocytosis. We conclude that AVR3a is a multifunctional effector that can suppress BAK1/SERK3-mediated immunity through at least two different pathways.

  10. Variation in Phytophthora infestans: sources and implications

    NARCIS (Netherlands)

    Flier, W.G.

    2002-01-01

    Uitgebreide samenvatting van de dissertatie van Wilbert G. Flier over de oömyceet Phytophthora infestans (Monst.) de Bary, de veroorzaker van 'het kwaad' ofwel de aardappelziekte in de teelt van aardappelen en tomaten

  11. Tomato late blight (Phytophthora infestans) in Uganda

    NARCIS (Netherlands)

    Tumwine, J.; Frinking, H.D.; Jeger, M.J.

    2002-01-01

    A survey on the tomato late blight situation and current practices for disease management was carried out in Uganda using an informal structured questionnaire approach. Ten districts from different agroclimatic zones were selected for the survey. Phytophthora infestans isolates from tomatoes were ob

  12. The nature of biotrophy in Phytophthora infestans

    NARCIS (Netherlands)

    Scheepens, P.C.

    1978-01-01

    Phytophthora infestans, being an intermediate type between the facultative and obligate parasites among the Peronosporales (class Oomycetes ), was used to study the factors which are responsible for the inability of

  13. Variation in Phytophthora infestans : sources and implications

    NARCIS (Netherlands)

    Flier, W.

    2001-01-01

    The oomycete pseudofungus Phytophthora infestans (Mont.) de Bary, the causal organism of late blight, is considered to be one of the most devastating pathogens affecting potatoes and tomatoes worldwide. In Europe, the pathogen caused severe epidemics on potatoes after its introduction in 1845. Late

  14. Genetic diversity of Phytophthora infestans in the Northern Andean region

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    Grünwald Niklaus J

    2011-02-01

    Full Text Available Abstract Background Phytophthora infestans (Mont. de Bary, the causal agent of potato late blight, is responsible for tremendous crop losses worldwide. Countries in the northern part of the Andes dedicate a large proportion of the highlands to the production of potato, and more recently, solanaceous fruits such as cape gooseberry (Physalis peruviana and tree tomato (Solanum betaceum, all of which are hosts of this oomycete. In the Andean region, P. infestans populations have been well characterized in Ecuador and Peru, but are poorly understood in Colombia and Venezuela. To understand the P. infestans population structure in the Northern part of the Andes, four nuclear regions (ITS, Ras, β-tubulin and Avr3a and one mitochondrial (Cox1 region were analyzed in isolates of P. infestans sampled from different hosts in Colombia and Venezuela. Results Low genetic diversity was found within this sample of P. infestans isolates from crops within several regions of Colombia and Venezuela, revealing the presence of clonal populations of the pathogen in this region. We detected low frequency heterozygotes, and their distribution patterns might be a consequence of a high migration rate among populations with poor effective gene flow. Consistent genetic differentiation exists among isolates from different regions. Conclusions The results here suggest that in the Northern Andean region P. infestans is a clonal population with some within-clone variation. P. infestans populations in Venezuela reflect historic isolation that is being reinforced by a recent self-sufficiency of potato seeds. In summary, the P. infestans population is mainly shaped by migration and probably by the appearance of variants of key effectors such as Avr3a.

  15. Phytophthora infestans population structure: a worldwide scale

    Directory of Open Access Journals (Sweden)

    Cárdenas Toquica Martha

    2012-08-01

    Full Text Available Phytophthora infestans, the causal agent of late blight disease in potato and other members of the Solanaceae family, is responsible for causing the Irish potato famine and, even today, it causes enormous economic losses all over the world. For the establishment of an adequate pest management strategy, the determination of population structure is required. To characterize P. infestans populations worldwide two allozymes, Gpi (Glucose-6-phospate isomerase and Pep (Peptidase, the RG57 DNA RFLP fingerprinting probe, as well as resistance to the fungicide metalaxyl and the mating type, have been used as markers. P. infestans populations in Mexico have been one of the main focuses of research in the population biology of this pathogen because this country has been considered as one of the possible centers of origin of this oomycete. In this review we present the population structure of P. infestans in Mexico, Europe, Africa, Asia, North America, and South America expanding on the present situation of P. infestans in Colombia. Finally, we will discuss different lines of research that are being carried out today with respect to P. infestans in Colombia, which have shown the importance of continuing the study of this devastating plant pathogen in our country.

  16. PHYTOPHTHORA INFESTANS POPULATION STRUCTURE: A WORLDWIDE SCALE

    Directory of Open Access Journals (Sweden)

    MARTHA CÁRDENAS

    2012-01-01

    Full Text Available Phytophthora infestans, the causal agent of late blight disease in potato and other members of the Solanaceae family, is responsible for causing the Irish potato famine and, even today, it causes enormous economic losses all over the world. For the establishment of an adequate pest management strategy, the determination of the pathogen’s population structure is required. To characterize P. infestans populations worldwide two allozymes, Gpi (Glucose-6-phospate isomerase and Pep (Peptidase, the RG57 DNA RFLP fingerprinting probe, as well as resistance to the fungicide metalaxyl and mating type, have been used as markers. P. infestans populations in Mexico have been one of the main focuses of research in the population biology of this pathogen because this country has been considered as one of the possible centers of origin of this oomycete. In this review we present the population structure of P. infestans in Mexico, Europe, Africa, Asia, North America, and South America, expanding it on the present situation of P. infestans in Colombia. Finally, we will discuss different lines of research that are being carried out today with respect to P. infestans in Colombia, which have shown the importance of continuing the study of this devastating plant pathogen in our country.

  17. The interplay between a Phytophthora RXLR effector and an Arabidopsis lectin receptor kinase

    NARCIS (Netherlands)

    Bouwmeester, K.

    2010-01-01

    Phytophthora infestans – the causal agent of potato late blight – secretes a plethora of effector proteins to facilitate plant infection. The central subject of this thesis is ipiO, one of the first cloned Phytophthora genes with a putative function in pathogenicity as was anticipated based on its i

  18. Phytophthora infestans specific phosphorylation patterns and new putative control targets.

    Science.gov (United States)

    Frades, Itziar; Andreasson, Erik

    2016-04-01

    In this study we applied biomathematical searches of gene regulatory mechanisms to learn more about oomycete biology and to identify new putative targets for pesticides or biological control against Phytophthora infestans. First, oomycete phylum-specific phosphorylation motifs were found by discriminative n-gram analysis. We found 11.600 P. infestans specific n-grams, mapping 642 phosphoproteins. The most abundant group among these related to phosphatidylinositol metabolism. Due to the large number of possible targets found and our hypothesis that multi-level control is a sign of usefulness as targets for intervention, we identified overlapping targets with a second screen. This was performed to identify proteins dually regulated by small RNA and phosphorylation. We found 164 proteins to be regulated by both sRNA and phosphorylation and the dominating functions where phosphatidylinositol signalling/metabolism, endocytosis, and autophagy. Furthermore we performed a similar regulatory study and discriminative n-gram analysis of proteins with no clear orthologs in other species and proteins that are known to be unique to P. infestans such as the RxLR effectors, Crinkler (CRN) proteins and elicitins. We identified CRN proteins with specific phospho-motifs present in all life stages. PITG_12626, PITG_14042 and PITG_23175 are CRN proteins that have species-specific phosphorylation motifs and are subject to dual regulation.

  19. De rol van heterotrimere G-eiwitten in de ontwikkeling en virulentie van Phytophthora infestans

    NARCIS (Netherlands)

    Latijnhouwers, M.

    2003-01-01

    Onderzoek naar de ziekteverwekker Phytophthora infestans die de aardappelziekte veroorzaakt. Samenvatting van het proefschrift van Maita J.M. Latijnhouwers getiteld: 'The role of heterotrimeric G-proteins in development and virulence of Phytophthora infestans'

  20. Transformation of the oomycete pathogen, Phytophthora infestans.

    Science.gov (United States)

    Judelson, H S; Tyler, B M; Michelmore, R W

    1991-01-01

    A stable transformation procedure has been developed for Phytophthora infestans, an oomycete fungus that causes the late blight diseases of potato and tomato. This is the first description of reliable methods for transformation in an oomycete pathogen. Drug-resistant transformants were obtained by using vectors that contained bacterial genes for resistance to hygromycin B or G418 fused to promoters and terminators from the Hsp70 and Ham34 genes of the oomycete, Bremia lactucae. Using polyethylene glycol and CaCl2, vector DNA was introduced into protoplasts as a complex with cationic liposomes or with carrier DNA only. Transformants were obtained at similar frequencies with each combination of promoter and selectable marker and were confirmed by DNA and RNA hybridization and phosphotransferase assays. Transformation occurred through the integration of single or tandemly repeated copies of the plasmids into genomic DNA, conferring mitotically stable drug-resistant phenotypes. The sizes of the marker gene mRNAs in each transformant and the results of transcript mapping studies were consistent with the function of the B. lactucae regulatory sequences in P. infestans. A hygromycin-resistant transformant was tested and found to maintain pathogenicity, indicating that the gene transfer procedure will be useful for the molecular analysis of genes relevant to disease.

  1. Phytophthora infestans POPULATION STRUCTURE: A WORLDWIDE SCALE Estructura poblacional de Phytophthora infestans: una escala global

    Directory of Open Access Journals (Sweden)

    MARTHA CÁRDENAS

    2012-05-01

    Full Text Available Phytophthora infestans, the causal agent of late blight disease in potato and other members of the Solanaceae family, is responsible for causing the Irish potato famine and, even today, it causes enormous economic losses all over the world. For the establishment of an adequate pest management strategy, the determination of the pathogen's population structure is required. To characterize P. infestans populations worldwide two allozymes, Gpi (Glucose-6-phospate isomerase and Pep ( Pep tidase, the RG57 DNA RFLP fingerprinting probe, as well as resistance to the fungicide metalaxyl and mating type, have been used as markers. P. infestans populations in Mexico have been one of the main focuses of research in the population biology of this pathogen because this country has been considered as one of the possible centers of origin of this oomycete. In this review we present the population structure of P. infestans in Mexico, Europe, Africa, Asia, North America, and South America, expanding it on the present situation of P. infestans in Colombia. Finally, we will discuss different lines of research that are being carried out today with respect to P. infestans in Colombia, which have shown the importance of continuing the study of this devastating plant pathogen in our country.Phytophthora infestans, el agente causal del tizón tardío de la papa y otros miembros de la familia de las Solanáceas, es el responsable de la gran hambruna irlandesa y aún hoy sigue causando grandes pérdidas económicas alrededor del planeta. Para establecer estrategias de control adecuadas contra este patógeno se requiere comprender la estructura poblacional del mismo. Mundialmente se han utilizado como marcadores las aloenzimas, Gpi (Glucosa-6-fosfato isomerasa y Pep (Peptidasa y la sonda de fingerprinting de RFLP (Polimorfismos de la Longitud de los Fragmentos de Restricción, RG57. De igual forma, la resistencia al fungicida metalaxyl y el tipo de apareamiento, han sido

  2. The C-terminal half of Phytophthora infestans RXLR effector AVR3a is sufficient to trigger R3a-mediated hypersensitivity and suppress INF1-induced cell death in Nicotiana benthamiana.

    Science.gov (United States)

    Bos, Jorunn I B; Kanneganti, Thirumala-Devi; Young, Carolyn; Cakir, Cahid; Huitema, Edgar; Win, Joe; Armstrong, Miles R; Birch, Paul R J; Kamoun, Sophien

    2006-10-01

    The RXLR cytoplasmic effector AVR3a of Phytophthora infestans confers avirulence on potato plants carrying the R3a gene. Two alleles of Avr3a encode secreted proteins that differ in only three amino acid residues, two of which are in the mature protein. Avirulent isolates carry the Avr3a allele, which encodes AVR3aKI (containing amino acids C19, K80 and I103), whereas virulent isolates express only the virulence allele avr3a, encoding AVR3aEM (S19, E80 and M103). Only the AVR3aKI protein is recognized inside the plant cytoplasm where it triggers R3a-mediated hypersensitivity. Similar to other oomycete avirulence proteins, AVR3aKI carries a signal peptide followed by a conserved motif centered on the consensus RXLR sequence that is functionally similar to a host cell-targeting signal of malaria parasites. The interaction between Avr3a and R3a can be reconstructed by their transient co-expression in Nicotiana benthamiana. We exploited the N. benthamiana experimental system to further characterize the Avr3a-R3a interaction. R3a activation by AVR3aKI is dependent on the ubiquitin ligase-associated protein SGT1 and heat-shock protein HSP90. The AVR3aKI and AVR3aEM proteins are equally stable in planta, suggesting that the difference in R3a-mediated death cannot be attributed to AVR3aEM protein instability. AVR3aKI is able to suppress cell death induced by the elicitin INF1 of P. infestans, suggesting a possible virulence function for this protein. Structure-function experiments indicated that the 75-amino acid C-terminal half of AVR3aKI, which excludes the RXLR region, is sufficient for avirulence and suppression functions, consistent with the view that the N-terminal region of AVR3aKI and other RXLR effectors is involved in secretion and targeting but is not required for effector activity. We also found that both polymorphic amino acids, K80 and I103, of mature AVR3a contribute to the effector functions.

  3. Survival of Phytophthora infestans in Surface Water.

    Science.gov (United States)

    Porter, Lyndon D; Johnson, Dennis A

    2004-04-01

    ABSTRACT Coverless petri dishes with water suspensions of sporangia and zoospores of Phytophthora infestans were embedded in sandy soil in eastern Washington in July and October 2001 and July 2002 to quantify longevity of spores in water under natural conditions. Effects of solar radiation intensity, presence of soil in petri dishes (15 g per dish), and a 2-h chill period on survival of isolates of clonal lineages US-8 and US-11 were investigated. Spores in water suspensions survived 0 to 16 days under nonshaded conditions and 2 to 20 days under shaded conditions. Mean spore survival significantly increased from 1.7 to 5.8 days when soil was added to the water. Maximum survival time of spores in water without soil exposed to direct sunlight was 2 to 3 days in July and 6 to 8 days in October. Mean duration of survival did not differ significantly between chilled and nonchilled sporangia, but significantly fewer chilled spores survived for extended periods than that of nonchilled spores. Spores of US-11 and US-8 isolates did not differ in mean duration of survival, but significantly greater numbers of sporangia of US-8 survived than did sporangia of US-11 in one of three trials.

  4. The Irish potato famine pathogen Phytophthora infestans translocates the CRN8 kinase into host plant cells.

    Science.gov (United States)

    van Damme, Mireille; Bozkurt, Tolga O; Cakir, Cahid; Schornack, Sebastian; Sklenar, Jan; Jones, Alexandra M E; Kamoun, Sophien

    2012-01-01

    Phytopathogenic oomycetes, such as Phytophthora infestans, secrete an arsenal of effector proteins that modulate plant innate immunity to enable infection. We describe CRN8, a host-translocated effector of P. infestans that has kinase activity in planta. CRN8 is a modular protein of the CRN effector family. The C-terminus of CRN8 localizes to the host nucleus and triggers cell death when the protein is expressed in planta. Cell death induction by CRN8 is dependent on its localization to the plant nucleus, which requires a functional nuclear localization signal (NLS). The C-terminal sequence of CRN8 has similarity to a serine/threonine RD kinase domain. We demonstrated that CRN8 is a functional RD kinase and that its auto-phosphorylation is dependent on an intact catalytic site. Co-immunoprecipitation experiments revealed that CRN8 forms a dimer or multimer. Heterologous expression of CRN8 in planta resulted in enhanced virulence by P. infestans. In contrast, in planta expression of the dominant-negative CRN8(R469A;D470A) resulted in reduced P. infestans infection, further implicating CRN8 in virulence. Overall, our results indicate that similar to animal parasites, plant pathogens also translocate biochemically active kinase effectors inside host cells.

  5. The Irish Potato Famine Pathogen Phytophthora infestans Translocates the CRN8 Kinase into Host Plant Cells

    Science.gov (United States)

    van Damme, Mireille; Bozkurt, Tolga O.; Cakir, Cahid; Schornack, Sebastian; Sklenar, Jan; Jones, Alexandra M. E.; Kamoun, Sophien

    2012-01-01

    Phytopathogenic oomycetes, such as Phytophthora infestans, secrete an arsenal of effector proteins that modulate plant innate immunity to enable infection. We describe CRN8, a host-translocated effector of P. infestans that has kinase activity in planta. CRN8 is a modular protein of the CRN effector family. The C-terminus of CRN8 localizes to the host nucleus and triggers cell death when the protein is expressed in planta. Cell death induction by CRN8 is dependent on its localization to the plant nucleus, which requires a functional nuclear localization signal (NLS). The C-terminal sequence of CRN8 has similarity to a serine/threonine RD kinase domain. We demonstrated that CRN8 is a functional RD kinase and that its auto-phosphorylation is dependent on an intact catalytic site. Co-immunoprecipitation experiments revealed that CRN8 forms a dimer or multimer. Heterologous expression of CRN8 in planta resulted in enhanced virulence by P. infestans. In contrast, in planta expression of the dominant-negative CRN8R469A;D470A resulted in reduced P. infestans infection, further implicating CRN8 in virulence. Overall, our results indicate that similar to animal parasites, plant pathogens also translocate biochemically active kinase effectors inside host cells. PMID:22927814

  6. The Irish potato famine pathogen Phytophthora infestans translocates the CRN8 kinase into host plant cells.

    Directory of Open Access Journals (Sweden)

    Mireille van Damme

    Full Text Available Phytopathogenic oomycetes, such as Phytophthora infestans, secrete an arsenal of effector proteins that modulate plant innate immunity to enable infection. We describe CRN8, a host-translocated effector of P. infestans that has kinase activity in planta. CRN8 is a modular protein of the CRN effector family. The C-terminus of CRN8 localizes to the host nucleus and triggers cell death when the protein is expressed in planta. Cell death induction by CRN8 is dependent on its localization to the plant nucleus, which requires a functional nuclear localization signal (NLS. The C-terminal sequence of CRN8 has similarity to a serine/threonine RD kinase domain. We demonstrated that CRN8 is a functional RD kinase and that its auto-phosphorylation is dependent on an intact catalytic site. Co-immunoprecipitation experiments revealed that CRN8 forms a dimer or multimer. Heterologous expression of CRN8 in planta resulted in enhanced virulence by P. infestans. In contrast, in planta expression of the dominant-negative CRN8(R469A;D470A resulted in reduced P. infestans infection, further implicating CRN8 in virulence. Overall, our results indicate that similar to animal parasites, plant pathogens also translocate biochemically active kinase effectors inside host cells.

  7. Validation of a tuber blight (Phytophthora infestans) prediction model

    Science.gov (United States)

    Potato tuber blight caused by Phytophthora infestans accounts for significant losses in storage. There is limited published quantitative data on predicting tuber blight. We validated a tuber blight prediction model developed in New York with cultivars Allegany, NY 101, and Katahdin using independent...

  8. Potato late blight epidemics and population structure of Phytophthora infestans.

    NARCIS (Netherlands)

    Zwankhuizen, M.J.

    1998-01-01

    Potato late blight is caused by the fungus Phytophthora infestans . To study the relative importance of oospores in the epidemiology, and to estimate the relative impact of various infection sources, late blight epidemics in Southern Flevoland (The Netherlands) were studied using epidemiological and

  9. Stable transformation of the oomycete, Phytophthora infestans, using microprojectile bombardment

    DEFF Research Database (Denmark)

    Cvitanich, Cristina; Judelson, Howard S.

    2003-01-01

    Germinated asexual sporangia, zoospores, and mycelia of Phytophthora infestans were transformed to G418-resistance by microprojectile bombardment. After optimization, an average of 14 transformants/shot were obtained, using 10(6) germinated sporangia and gold particles coated with 1 microg...

  10. A Surface Plasmon Resonance Immunobiosensor for Detection of Phytophthora infestans

    DEFF Research Database (Denmark)

    Skottrup, Peter; Frøkiær, Hanne; Hejgaard, Jørn;

    In this study we focused on the development of a Surface Plasmon Resonance (SPR) immunosensor for Phytophthora infestans detection. The fungus-like organism is the cause of potato late blight and is a major problem in potato growing regions of the world. Efficient control is dependent on early...

  11. Production, survival and infectivity of oospores of Phytophthora infestans

    NARCIS (Netherlands)

    Turkensteen, L.J.; Flier, W.G.; Mulder, A.; Wanningen, R.

    2000-01-01

    The formation of oospores of Phytophthora infestans was studied in tomato and potato crops and volunteer plants under field conditions, and in laboratory tests with leaf discs of potato cultivars differing in their level of race-nonspecific resistance. Oospores were readily detected in

  12. The biology of Phytophthora infestans at its center of origin

    NARCIS (Netherlands)

    Grünwald, N.J.; Flier, W.G.

    2005-01-01

    The central highlands of Mexico are considered to be a center of genetic diversity for both the potato late blight pathogen and for tuber-bearing Solanum spp. Recent work conducted in Mexico and South America sheds new light on the biology and evolution of Phytophthora infestans and other related Ph

  13. Multi-scale modelling of infection pressure from Phytophthora infestans

    NARCIS (Netherlands)

    Skelsey, P.; Werf, van der W.; Kessel, G.J.T.; Rossing, W.A.H.; Holtslag, A.A.M.

    2007-01-01

    Management of potato late blight could benefit from prediction of the risk posed to potato fields from external inoculum sources of Phytophthora infestans. Influx of inoculum depends on a complex interplay of population biological, atmospheric and spore survival processes, and is difficult to predic

  14. Signatures of selection and host-adapted gene expression of the Phytophthora infestans RNA silencing suppressor PSR2.

    Science.gov (United States)

    de Vries, Sophie; von Dahlen, Janina K; Uhlmann, Constanze; Schnake, Anika; Kloesges, Thorsten; Rose, Laura E

    2017-01-01

    Phytophthora infestans is a devastating pathogen in agricultural systems. Recently, an RNA silencing suppressor (PSR2, 'Phytophthora suppressor of RNA silencing 2') has been described in P. infestans. PSR2 has been shown to increase the virulence of Phytophthora pathogens on their hosts. This gene is one of the few effectors present in many economically important Phytophthora species. In this study, we investigated: (i) the evolutionary history of PSR2 within and between species of Phytophthora; and (ii) the interaction between sequence variation, gene expression and virulence. In P. infestans, the highest PiPSR2 expression was correlated with decreased symptom expression. The highest gene expression was observed in the biotrophic phase of the pathogen, suggesting that PSR2 is important during early infection. Protein sequence conservation was negatively correlated with host range, suggesting host range as a driver of PSR2 evolution. Within species, we detected elevated amino acid variation, as observed for other effectors; however, the frequency spectrum of the mutations was inconsistent with strong balancing selection. This evolutionary pattern may be related to the conservation of the host target(s) of PSR2 and the absence of known corresponding R genes. In summary, our study indicates that PSR2 is a conserved effector that acts as a master switch to modify plant gene regulation early during infection for the pathogen's benefit. The conservation of PSR2 and its important role in virulence make it a promising target for pathogen management.

  15. Discovery of Phytophthora infestans genes expressed in planta through mining of cDNA libraries.

    Directory of Open Access Journals (Sweden)

    Roberto Sierra

    Full Text Available BACKGROUND: Phytophthora infestans (Mont. de Bary causes late blight of potato and tomato, and has a broad host range within the Solanaceae family. Most studies of the Phytophthora--Solanum pathosystem have focused on gene expression in the host and have not analyzed pathogen gene expression in planta. METHODOLOGY/PRINCIPAL FINDINGS: We describe in detail an in silico approach to mine ESTs from inoculated host plants deposited in a database in order to identify particular pathogen sequences associated with disease. We identified candidate effector genes through mining of 22,795 ESTs corresponding to P. infestans cDNA libraries in compatible and incompatible interactions with hosts from the Solanaceae family. CONCLUSIONS/SIGNIFICANCE: We annotated genes of P. infestans expressed in planta associated with late blight using different approaches and assigned putative functions to 373 out of the 501 sequences found in the P. infestans genome draft, including putative secreted proteins, domains associated with pathogenicity and poorly characterized proteins ideal for further experimental studies. Our study provides a methodology for analyzing cDNA libraries and provides an understanding of the plant--oomycete pathosystems that is independent of the host, condition, or type of sample by identifying genes of the pathogen expressed in planta.

  16. Transcriptional dynamics of Phytophthora infestans during sequential stages of hemibiotrophic infection of tomato.

    Science.gov (United States)

    Zuluaga, Andrea P; Vega-Arreguín, Julio C; Fei, Zhangjun; Ponnala, Lalit; Lee, Sang Jik; Matas, Antonio J; Patev, Sean; Fry, William E; Rose, Jocelyn K C

    2016-01-01

    Hemibiotrophic plant pathogens, such as the oomycete Phytophthora infestans, employ a biphasic infection strategy, initially behaving as biotrophs, where minimal symptoms are exhibited by the plant, and subsequently as necrotrophs, feeding on dead plant tissue. The regulation of this transition and the breadth of molecular mechanisms that modulate plant defences are not well understood, although effector proteins secreted by the pathogen are thought to play a key role. We examined the transcriptional dynamics of P. infestans in a compatible interaction with its host tomato (Solanum lycopersicum) at three infection stages: biotrophy; the transition from biotrophy to necrotrophy; and necrotrophy. The expression data suggest a tight temporal regulation of many pathways associated with the suppression of plant defence mechanisms and pathogenicity, including the induction of putative cytoplasmic and apoplastic effectors. Twelve of these were experimentally evaluated to determine their ability to suppress necrosis caused by the P. infestans necrosis-inducing protein PiNPP1.1 in Nicotiana benthamiana. Four effectors suppressed necrosis, suggesting that they might prolong the biotrophic phase. This study suggests that a complex regulation of effector expression modulates the outcome of the interaction.

  17. Variation in capsidiol sensitivity between Phytophthora infestans and Phytophthora capsici is consistent with their host range.

    Science.gov (United States)

    Giannakopoulou, Artemis; Schornack, Sebastian; Bozkurt, Tolga O; Haart, Dave; Ro, Dae-Kyun; Faraldos, Juan A; Kamoun, Sophien; O'Maille, Paul E

    2014-01-01

    Plants protect themselves against a variety of invading pathogenic organisms via sophisticated defence mechanisms. These responses include deployment of specialized antimicrobial compounds, such as phytoalexins, that rapidly accumulate at pathogen infection sites. However, the extent to which these compounds contribute to species-level resistance and their spectrum of action remain poorly understood. Capsidiol, a defense related phytoalexin, is produced by several solanaceous plants including pepper and tobacco during microbial attack. Interestingly, capsidiol differentially affects growth and germination of the oomycete pathogens Phytophthora infestans and Phytophthora capsici, although the underlying molecular mechanisms remain unknown. In this study we revisited the differential effect of capsidiol on P. infestans and P. capsici, using highly pure capsidiol preparations obtained from yeast engineered to express the capsidiol biosynthetic pathway. Taking advantage of transgenic Phytophthora strains expressing fluorescent markers, we developed a fluorescence-based method to determine the differential effect of capsidiol on Phytophtora growth. Using these assays, we confirm major differences in capsidiol sensitivity between P. infestans and P. capsici and demonstrate that capsidiol alters the growth behaviour of both Phytophthora species. Finally, we report intraspecific variation within P. infestans isolates towards capsidiol tolerance pointing to an arms race between the plant and the pathogens in deployment of defence related phytoalexins.

  18. Variation in capsidiol sensitivity between Phytophthora infestans and Phytophthora capsici is consistent with their host range.

    Directory of Open Access Journals (Sweden)

    Artemis Giannakopoulou

    Full Text Available Plants protect themselves against a variety of invading pathogenic organisms via sophisticated defence mechanisms. These responses include deployment of specialized antimicrobial compounds, such as phytoalexins, that rapidly accumulate at pathogen infection sites. However, the extent to which these compounds contribute to species-level resistance and their spectrum of action remain poorly understood. Capsidiol, a defense related phytoalexin, is produced by several solanaceous plants including pepper and tobacco during microbial attack. Interestingly, capsidiol differentially affects growth and germination of the oomycete pathogens Phytophthora infestans and Phytophthora capsici, although the underlying molecular mechanisms remain unknown. In this study we revisited the differential effect of capsidiol on P. infestans and P. capsici, using highly pure capsidiol preparations obtained from yeast engineered to express the capsidiol biosynthetic pathway. Taking advantage of transgenic Phytophthora strains expressing fluorescent markers, we developed a fluorescence-based method to determine the differential effect of capsidiol on Phytophtora growth. Using these assays, we confirm major differences in capsidiol sensitivity between P. infestans and P. capsici and demonstrate that capsidiol alters the growth behaviour of both Phytophthora species. Finally, we report intraspecific variation within P. infestans isolates towards capsidiol tolerance pointing to an arms race between the plant and the pathogens in deployment of defence related phytoalexins.

  19. Variation in Capsidiol Sensitivity between Phytophthora infestans and Phytophthora capsici Is Consistent with Their Host Range

    Science.gov (United States)

    Giannakopoulou, Artemis; Schornack, Sebastian; Bozkurt, Tolga O.; Haart, Dave; Ro, Dae-Kyun; Faraldos, Juan A.; Kamoun, Sophien; O’Maille, Paul E.

    2014-01-01

    Plants protect themselves against a variety of invading pathogenic organisms via sophisticated defence mechanisms. These responses include deployment of specialized antimicrobial compounds, such as phytoalexins, that rapidly accumulate at pathogen infection sites. However, the extent to which these compounds contribute to species-level resistance and their spectrum of action remain poorly understood. Capsidiol, a defense related phytoalexin, is produced by several solanaceous plants including pepper and tobacco during microbial attack. Interestingly, capsidiol differentially affects growth and germination of the oomycete pathogens Phytophthora infestans and Phytophthora capsici, although the underlying molecular mechanisms remain unknown. In this study we revisited the differential effect of capsidiol on P. infestans and P. capsici, using highly pure capsidiol preparations obtained from yeast engineered to express the capsidiol biosynthetic pathway. Taking advantage of transgenic Phytophthora strains expressing fluorescent markers, we developed a fluorescence-based method to determine the differential effect of capsidiol on Phytophtora growth. Using these assays, we confirm major differences in capsidiol sensitivity between P. infestans and P. capsici and demonstrate that capsidiol alters the growth behaviour of both Phytophthora species. Finally, we report intraspecific variation within P. infestans isolates towards capsidiol tolerance pointing to an arms race between the plant and the pathogens in deployment of defence related phytoalexins. PMID:25203155

  20. Five Reasons to Consider Phytophthora infestans a Reemerging Pathogen.

    Science.gov (United States)

    Fry, W E; Birch, P R J; Judelson, H S; Grünwald, N J; Danies, G; Everts, K L; Gevens, A J; Gugino, B K; Johnson, D A; Johnson, S B; McGrath, M T; Myers, K L; Ristaino, J B; Roberts, P D; Secor, G; Smart, C D

    2015-07-01

    Phytophthora infestans has been a named pathogen for well over 150 years and yet it continues to "emerge", with thousands of articles published each year on it and the late blight disease that it causes. This review explores five attributes of this oomycete pathogen that maintain this constant attention. First, the historical tragedy associated with this disease (Irish potato famine) causes many people to be fascinated with the pathogen. Current technology now enables investigators to answer some questions of historical significance. Second, the devastation caused by the pathogen continues to appear in surprising new locations or with surprising new intensity. Third, populations of P. infestans worldwide are in flux, with changes that have major implications to disease management. Fourth, the genomics revolution has enabled investigators to make tremendous progress in terms of understanding the molecular biology (especially the pathogenicity) of P. infestans. Fifth, there remain many compelling unanswered questions.

  1. Phenotypic and genotypic characterization of Italian Phytophthora infestans isolates

    Directory of Open Access Journals (Sweden)

    Federica SAVAZZINI

    2015-12-01

    Full Text Available Phytophthora infestans (Mont. de Bary causes late blight of potato. After the 1970s, several changes have occurred in the European P. infestans population, frequently associated with an increased virulence. While the genotypic and phenotypic diversity of P. infestans has been studied in-depth in northern and central Europe, only a few reports are available regarding Italian isolates, mainly based on phenotypic traits. We report data of phenotypic and genotypic characteristics of isolates collected from infected potato and tomato plants in different Italian regions in 2006‒2008. A prevalence of the A1 mating type and a majority of metalaxyl-resistant isolates were found. Tomato-derived isolates showed fungicide sensitivity, confirming previous reports. One of the isolates showed the rare IIb mitochondrial DNA haplotype. Genetic analyses of the single-sequence repeats (SSRs and of the internal transcribed spacers gave similar results, although SSRs gave the best discrimination of genotypes.

  2. Molecular tools to unravel the role of genes from Phytophthora infestans

    NARCIS (Netherlands)

    West, van P.

    2000-01-01

    The oomycete plant pathogen Phytophthora infestans is the causal agent of potato late blight. P. infestans is undoubtedly the best known and most studied Phytophthora species today. This is mainly because it is such a

  3. Molecular tools to unravel the role of genes from Phytophthora infestans

    NARCIS (Netherlands)

    West, van P.

    2000-01-01

    The oomycete plant pathogen Phytophthora infestans is the causal agent of potato late blight. P. infestans is undoubtedly the best known and most studied Phytophthora species today. This is mainly because it is such a devastating pathogen that can cause complete destruction of a potato field in only

  4. An in planta induced gene of Phytophthora infestans codes for ubiquitin

    NARCIS (Netherlands)

    Pieterse, C.M.J.; Risseeuw, E.P.; Davidse, L.C.

    1991-01-01

    An in planta induced gene of Phytophthora infestans (the causal organism of potato late blight) was selected from a genomic library by differential hybridization using labelled cDNA derived from poly(A)+ RNA of P. infestans grown in vitro and labelled cDNA made from potato-P. infestans interaction

  5. Characterization of Phytophthora infestans resistance to mefenoxam using FTIR spectroscopy.

    Science.gov (United States)

    Pomerantz, A; Cohen, Y; Shufan, E; Ben-Naim, Y; Mordechai, S; Salman, A; Huleihel, M

    2014-12-01

    Phytophthora infestans (P. infestans) is the causal agent of late blight in potato and tomato. This pathogen devastated the potato crops in Ireland more than a century years ago and is still causing great losses worldwide. Although fungicides controlling P. infestans have been used successfully for almost 100 years, some isolates have developed resistance to most common fungicides. Identification and characterization of these resistant isolates is required for better control of the disease. Current methods that are based on microbiological and molecular techniques are both expensive and time consuming. Fourier Transform Infra-Red spectroscopy (FTIR) is an inexpensive and reagent-free technique that provides accurate results in only a few minutes. In this study the infrared absorption spectra of the sporangia of P. infestans were measured to evaluate the potential of FTIR spectroscopy in tandem with multivariate analysis in order to classify those sporangia into those that were resistant and those that were non-resistant to the phenylamide fungicide mefenoxam. Based on individual measurements, our results show that FTIR spectroscopy enables classification of P. infestans isolates into mefenoxam resistant and mefenoxam non-resistant types with specificity of 81.9% and sensitivity of 75.5%. Using average spectra per leaf, it was possible to improve the classification results to 88% sensitivity and 95% specificity.

  6. Profiling the secretome and extracellular proteome of the potato late blight pathogen Phytophthora infestans.

    Science.gov (United States)

    Meijer, Harold J G; Mancuso, Francesco M; Espadas, Guadalupe; Seidl, Michael F; Chiva, Cristina; Govers, Francine; Sabidó, Eduard

    2014-08-01

    Oomycetes are filamentous organisms that cause notorious diseases, several of which have a high economic impact. Well known is Phytophthora infestans, the causal agent of potato late blight. Previously, in silico analyses of the genome and transcriptome of P. infestans resulted in the annotation of a large number of genes encoding proteins with an N-terminal signal peptide. This set is collectively referred to as the secretome and comprises proteins involved in, for example, cell wall growth and modification, proteolytic processes, and the promotion of successful invasion of plant cells. So far, proteomic profiling in oomycetes was primarily focused on subcellular, intracellular or cell wall fractions; the extracellular proteome has not been studied systematically. Here we present the first comprehensive characterization of the in vivo secretome and extracellular proteome of P. infestans. We have used mass spectrometry to analyze P. infestans proteins present in seven different growth media with mycelial cultures and this resulted in the consistent identification of over two hundred proteins. Gene ontology classification pinpointed proteins involved in cell wall modifications, pathogenesis, defense responses, and proteolytic processes. Moreover, we found members of the RXLR and CRN effector families as well as several proteins lacking an obvious signal peptide. The latter were confirmed to be bona fide extracellular proteins and this suggests that, similar to other organisms, oomycetes exploit non-conventional secretion mechanisms to transfer certain proteins to the extracellular environment.

  7. Analyses of genome architecture and gene expression reveal novel candidate virulence factors in the secretome of Phytophthora infestans

    Directory of Open Access Journals (Sweden)

    Cano Liliana M

    2010-11-01

    Full Text Available Abstract Background Phytophthora infestans is the most devastating pathogen of potato and a model organism for the oomycetes. It exhibits high evolutionary potential and rapidly adapts to host plants. The P. infestans genome experienced a repeat-driven expansion relative to the genomes of Phytophthora sojae and Phytophthora ramorum and shows a discontinuous distribution of gene density. Effector genes, such as members of the RXLR and Crinkler (CRN families, localize to expanded, repeat-rich and gene-sparse regions of the genome. This distinct genomic environment is thought to contribute to genome plasticity and host adaptation. Results We used in silico approaches to predict and describe the repertoire of P. infestans secreted proteins (the secretome. We defined the "plastic secretome" as a subset of the genome that (i encodes predicted secreted proteins, (ii is excluded from genome segments orthologous to the P. sojae and P. ramorum genomes and (iii is encoded by genes residing in gene sparse regions of P. infestans genome. Although including only ~3% of P. infestans genes, the plastic secretome contains ~62% of known effector genes and shows >2 fold enrichment in genes induced in planta. We highlight 19 plastic secretome genes induced in planta but distinct from previously described effectors. This list includes a trypsin-like serine protease, secreted oxidoreductases, small cysteine-rich proteins and repeat containing proteins that we propose to be novel candidate virulence factors. Conclusions This work revealed a remarkably diverse plastic secretome. It illustrates the value of combining genome architecture with comparative genomics to identify novel candidate virulence factors from pathogen genomes.

  8. Phytophthora suppressor of RNA silencing 2 is a conserved RxLR effector that promotes infection in soybean and Arabidopsis thaliana.

    Science.gov (United States)

    Xiong, Qin; Ye, Wenwu; Choi, Duseok; Wong, James; Qiao, Yongli; Tao, Kai; Wang, Yuanchao; Ma, Wenbo

    2014-12-01

    The genus Phytophthora consists of notorious and emerging pathogens of economically important crops. Each Phytophthora genome encodes several hundreds of cytoplasmic effectors, which are believed to manipulate plant immune response inside the host cells. However, the majority of Phytophthora effectors remain functionally uncharacterized. We recently discovered two effectors from the soybean stem and root rot pathogen Phytophthora sojae with the activity to suppress RNA silencing in plants. These effectors are designated Phytophthora suppressor of RNA silencing (PSRs). Here, we report that the P. sojae PSR2 (PsPSR2) belongs to a conserved and widespread effector family in Phytophthora. A PsPSR2-like effector produced by P. infestans (PiPSR2) can also suppress RNA silencing in plants and promote Phytophthora infection, suggesting that the PSR2 family effectors have conserved functions in plant hosts. Using Agrobacterium rhizogenes-mediated hairy roots induction, we demonstrated that the expression of PsPSR2 rendered hypersusceptibility of soybean to P. sojae. Enhanced susceptibility was also observed in PsPSR2-expressing Arabidopsis thaliana plants during Phytophthora but not bacterial infection. These experiments provide strong evidence that PSR2 is a conserved Phytophthora effector family that performs important virulence functions specifically during Phytophthora infection of various plant hosts.

  9. CHARACTERIZATION OF Phytophthora infestans POPULATIONS IN ANTIOQUIA, COLOMBIA CARACTERIZACIÓN DE LAS POBLACIONES DE Phytophthora infestan EN ANTIOQUIA, COLOMBIA

    Directory of Open Access Journals (Sweden)

    Elizabeth Gilchrist Ramelli

    2009-12-01

    Full Text Available From the Phytophthora infestans collection of the Universidad Nacional de Colombia, the isolates collected in different locations in Antioquia, Colombia between 1994 and 2000 were evaluated. These isolates were obtained from late blight lessons in different hosts. In 2000, these isolates were characterized by mating type, mitochondrial haplotype and virulence races. All isolates were of the A1 mating type and two mitochondrial haplotypes were identified: IIa, present in isolates from all the hosts tested, and Ib present only in isolates from tomato and water cucumber (Solanum muricatum. The Antioquia population of P. infestans showed a large complexity of virulence factors (10 out 11, especially those isolates collected from potato, while the tomato population was less complex. The A1 mating type and the mitochondrial haplotype IIa has been associated with the EC1 population that possibly is replacing the US1 population.De la colección de Phytophthora infestans de la Universidad Nacional de Colombia, se evaluaron aquellos aislamientos provenientes de diferentes localidades de Antioquia, Colombia entre 1994 y 2000. Dichos aislamientos fueron obtenidos de lesiones de tizón tardío en diferentes hospederos. En el año 2000 se caracterizaron por el tipo de apareamiento, haplotipo mitocondrial y razas de virulencia. Todos los aislamientos correspondieron al tipo de apareamiento A1 y se presentaron dos haplotipos mitocondriales: IIa, en aislamientos de todos los hospederos evaluados, y Ib solamente en aislamientos colectados de tomate y pepino de agua (Solanum muricatum. La población antioqueña de P. infestans presenta una amplia complejidad de factores de virulencia (10 de 11, especialmente para los aislamientos colectados de papa, mientras que la población de tomate fue menos compleja. El tipo de apareamiento A1 y el haplotipo mitocondrial IIa han sido asociados a la población EC1 que posiblemente está desplazando la población US1.

  10. Beleidsondersteunend Onderzoek Plantgezondheid BO-06 Resultaten 2009 : Phytophthora infestans (BO-06-008)

    NARCIS (Netherlands)

    Boonekamp, P.M.

    2010-01-01

    Een verzameling artikelen of rapporten over plantgezondheid. Het thema is Phytophthora infestans. Het plantgezondheidsonderzoek richt zich nog veel op het optimaliseren van bestaande methoden en technieken en korte termijnsuccesjes, vindt Piet Boonekamp. Voor een wezenlijke verduurzaming van plantge

  11. Stability of partial resistance in potato cultivars exposed to aggressive strains of Phytophthora infestans

    NARCIS (Netherlands)

    Flier, W.G.; Bosch, van den G.B.M.; Turkensteen, L.J.

    2003-01-01

    Potato cultivars were evaluated for their resistance responses to aggressive strains of Phytophthora infestans in field and laboratory experiments. Analysis of variance revealed differential cultivar-by-isolate interactions for both foliar and tuber blight resistance. Differential responses occur as

  12. Understanding the molecular basis of the resistance of Phytophthora infestans to fungicides by functional genomics

    Science.gov (United States)

    Development of resistance to fungicides is a major concern in managing potato late blight disease caused by Phytophthora infestans. The problem is P. infestans is capable of sexual recombination contributing to increased strain variability and high adaptability that hastens the development of resis...

  13. Discovering the next generation of late blight resistance genes – can we battle Phytophthora infestans evolution

    Science.gov (United States)

    Potato late blight, caused by the oomycete pathogen Phytophthora infestans, is one of the most destructive plant diseases. RB from Solanum bulbocastanum encodes a CC-NB-LRR (CNL) protein that confers partial resistance to most P. infestans isolates through its recognition of the corresponding pathog...

  14. Variability in virulence and the race concept in Phytophthora infestans (Mont. de Bary

    Directory of Open Access Journals (Sweden)

    Ludwik S. Sujkowski

    2014-08-01

    Full Text Available Variability in virulence and aggressiveness was studied in 102 single zoospore isolates originating from 4 field isolates of Phytophthora infestans. Field isolates appeared to be mixtures of a wide spectrum of phenotypes differing in both characters as mentioned above. Race concept in P. infestans has been discussed.

  15. Rapid Determination of Phytophthora infestans sporangia Using a Surface Plasmon Resonance Immunosensor

    DEFF Research Database (Denmark)

    Skottrup, Peter; Nicolaisen, Mogens; Justesen, Annemarie Fejer

    2007-01-01

    Phytophthora infestans is the cause of late blight disease in potato and is an economically important pathogen worldwide. Early disease detection is important to implement disease control measures. In this study a surface plasmon resonance (SPR) immunosensor for detection of P. infestans sporangia...

  16. Rapid Determination of Phytophthora infestans sporangia Using a Surface Plasmon Resonance Immunosensor

    DEFF Research Database (Denmark)

    Skottrup, Peter Durand; Nicolaisen, Mogens; Justesen, Annemarie Fejer

    2007-01-01

    Phytophthora infestans is the cause of late blight disease in potato and is an economically important pathogen worldwide. Early disease detection is important to implement disease control measures. In this study a surface plasmon resonance (SPR) immunosensor for detection of P. infestans sporangi...

  17. Multiplex SSR analysis of Phytophthora infestans in different countries and the importance for potato breeding

    NARCIS (Netherlands)

    Li, Y.

    2012-01-01

    Potato is the most important non-cereal crop in the world. Late blight, caused by the oomycete pathogen Phytophthora infestans, is the most devastating disease of potato. In the mid-19th century, P. infestans attacked the European potato fields and this resulted in a widespread famine in Ireland and

  18. Genome sequence and analysis of the Irish potato famine pathogen Phytophthora infestans

    NARCIS (Netherlands)

    Haas, B.J.; Kamoun, S.; Zody, M.C.; Jiang, R.H.Y.; Handsaker, R.E.; Cano, L.M.; Grabherr, M.; Kodira, C.D.; Raffaele, S.; Torto-Alalibo, T.; Bozkurt, T.O.; Ah-Fong, A.M.V.; Alvarado, L.; Anderson, V.L.; Armstrong, M.R.; Avrova, A.; Baxter, L.; Beynon, J.; Boevink, P.C.; Bollmann, S.R.; Bos, J.I.B.; Bulone, V.; Cai, G.; Cakir, C.; Carrington, J.C.; Chawner, M.; Conti, L.; Costanzo, S.; Ewan, R.; Fahlgren, N.; Fischbach, M.A.; Fugelstad, J.; Gilroy, E.M.; Gnerre, S.; Green, P.J.; Grenville-Briggs, L.J.; Griffith, J.; Grunwald, N.J.; Horn, K.; Horner, N.R.; Hu, C.H.; Huitema, E.; Jeong, D.H.; Jones, A.M.E.; Jones, J.D.G.; Jones, R.W.; Karlsson, E.K.; Kunjeti, S.G.; Lamour, K.; Liu, Z.; Ma, L.; Maclean, D.; Chibucos, M.C.; McDonald, H.; McWalters, J.; Meijer, H.J.G.; Morgan, W.; Morris, P.F.; Munro, C.A.; O'Neill, K.; Ospina-Giraldo, M.; Pinzon, A.; Pritchard, L.; Ramsahoye, B.; Ren, Q.; Restrepo, S.; Roy, S.; Sadanandom, A.; Savidor, A.; Schornack, S.; Schwartz, D.C.; Schumann, U.D.; Schwessinger, B.; Seyer, L.; Sharpe, T.; Silvar, C.; Song, J.; Studholme, D.J.; Sykes, S.; Thines, M.; Vondervoort, van de P.J.I.; Phuntumart, V.; Wawra, S.; Weide, R.; Win, J.; Young, C.; Zhou, S.; Fry, W.; Meyers, B.C.; West, van P.; Ristaino, J.; Govers, F.; Birch, P.R.J.; Whisson, S.C.; Judelson, H.S.; Nusbaum, C.

    2009-01-01

    Phytophthora infestans is the most destructive pathogen of potato and a model organism for the oomycetes, a distinct lineage of fungus-like eukaryotes that are related to organisms such as brown algae and diatoms. As the agent of the Irish potato famine in the mid-nineteenth century, P. infestans ha

  19. An in planta induced gene of Phytophthora infestans codes for ubiquitin

    NARCIS (Netherlands)

    Pieterse, C.M.J.; Risseeuw, E.P.; Davidse, L.C.

    1991-01-01

    An in planta induced gene of Phytophthora infestans (the causal organism of potato late blight) was isolated from a genomic library by differential hybridization using labelled cDNA derived from poly(A)⁺ RNA of P. infestans grown in vitro and labelled cDNA made from potato-P,

  20. Multiplex SSR analysis of Phytophthora infestans in different countries and the importance for potato breeding

    NARCIS (Netherlands)

    Li, Y.

    2012-01-01

    Potato is the most important non-cereal crop in the world. Late blight, caused by the oomycete pathogen Phytophthora infestans, is the most devastating disease of potato. In the mid-19th century, P. infestans attacked the European potato fields and this resulted in a widespread famine in Ireland and

  1. Epidemiological importance of Solanum sisymbriifolium, S. nigrum and S. dulcamara as alternative hosts for Phytophthora infestans

    NARCIS (Netherlands)

    Flier, W.G.; Bosch, van den G.B.M.; Turkensteen, L.J.

    2003-01-01

    Lesions of Phytophthora infestans were found on woody nightshade (Solanum dulcamara), black nightshade (S. nigrum) and S. sisymbriifolium during a nationwide late blight survey in the Netherlands in 1999 and 2000. Pathogenicity and spore production of P. infestans isolates collected from potato (S.

  2. Large subclonal variation in Phytophthora infestans populations associated with Ecuadorian potato landraces

    NARCIS (Netherlands)

    Delgado, R.A.; Monteros-Altamiro, A.R.; Li, Y.; Visser, R.G.F.; Lee, van der T.A.J.; Vosman, B.

    2013-01-01

    The population of Phytophthora infestans on potato landraces in three provinces (Carchi, Chimborazo and Loja) of Ecuador was analysed. All isolates (n = 66) were of the A1 mating type. Simple sequence repeats (SSR) were used to assess the genetic diversity of the isolates. The P. infestans isolates

  3. Phytophthora infestans isolates lacking class I ipiO variants are virulent on Rpi-blb1 potato.

    Science.gov (United States)

    Champouret, Nicolas; Bouwmeester, Klaas; Rietman, Hendrik; van der Lee, Theo; Maliepaard, Chris; Heupink, Anika; van de Vondervoort, Peter J I; Jacobsen, Evert; Visser, Richard G F; van der Vossen, Edwin A G; Govers, Francine; Vleeshouwers, Vivianne G A A

    2009-12-01

    A strategy to control the devastating late blight disease is providing potato cultivars with genes that are effective in resistance to a broad spectrum of Phytophthora infestans isolates. Thus far, most late blight resistance (R) genes that were introgressed in potato were quickly defeated. In contrast, the Rpi-blb1 gene originating from Solanum bulbocastanum has performed as an exclusive broad-spectrum R gene for many years. Recently, the RXLR effector family ipiO was identified to contain Avr-blb1. Monitoring the genetic diversity of the ipiO family in a large set of isolates of P. infestans and related species resulted in 16 ipiO variants in three distinct classes. Class I and class II but not class III ipiO variants induce cell death when coinfiltrated with Rpi-blb1 in Nicotiana benthamiana. Class I is highly diverse and is represented in all analyzed P. infestans isolates except two Mexican P. infestans isolates, and these were found virulent on Rpi-blb1 plants. In its C-terminal domain, IPI-O contains a W motif that is essential for triggering Rpi-blb1-mediated cell death and is under positive selection. This study shows that profiling the variation of Avr-blb1 within a P. infestans population is instrumental for predicting the effectiveness of Rpi-blb1-mediated resistance in potato.

  4. Activation of defense against Phytophthora infestans in potato by down-regulation of syntaxin gene expression.

    Science.gov (United States)

    Eschen-Lippold, Lennart; Landgraf, Ramona; Smolka, Ulrike; Schulze, Sebastian; Heilmann, Mareike; Heilmann, Ingo; Hause, Gerd; Rosahl, Sabine

    2012-03-01

    The oomycete Phytophthora infestans is the causal agent of late blight, the most devastating disease of potato. The importance of vesicle fusion processes and callose deposition for defense of potato against Phytophthora infestans was analyzed. Transgenic plants were generated, which express RNA interference constructs targeted against plasma membrane-localized SYNTAXIN-RELATED 1 (StSYR1) and SOLUBLE N-ETHYLMALEIMIDE-SENSITIVE FACTOR ADAPTOR PROTEIN 33 (StSNAP33), the potato homologs of Arabidopsis AtSYP121 and AtSNAP33, respectively. Phenotypically, transgenic plants grew normally, but showed spontaneous necrosis and chlorosis formation at later stages. In response to infection with Phytophthora infestans, increased resistance of StSYR1-RNAi plants, but not StSNAP33-RNAi plants, was observed. This increased resistance correlated with the constitutive accumulation of salicylic acid and PR1 transcripts. Aberrant callose deposition in Phytophthora infestans-infected StSYR1-RNAi plants coincided with decreased papilla formation at penetration sites. Resistance against the necrotrophic fungus Botrytis cinerea was not significantly altered. Infiltration experiments with bacterial solutions of Agrobacterium tumefaciens and Escherichia coli revealed a hypersensitive phenotype of both types of RNAi lines. The enhanced defense status and the reduced growth of Phytophthora infestans on StSYR1-RNAi plants suggest an involvement of syntaxins in secretory defense responses of potato and, in particular, in the formation of callose-containing papillae.

  5. Sensitivities of Phytophthora infestans to Metalaxyl, Cymoxanil, and Dimethomorph

    Institute of Scientific and Technical Information of China (English)

    ZHU Gui-ning; HUANG Fu-xin; FENG Lan-xiang; QIN Bi-xia; YANG Yu-hong; CHEN Yong-hui; LU Xiu-hong

    2008-01-01

    The isolates of Phytophthora infestans on tomato in the Guangxi Zhuang Autonomous Region, China, were determined for the sensitivities to metalaxyl, cymoxanil and dimethomorph to give the basic information for integrating disease management. Sensitivities were tested by measuring the radial growth on agar medium amended with fungicide, compared with the floating-leaf-disk method. 239 isolates were collected from eight tomato growing areas during 2000-2006. The testing results indicated that the frequencies of sensitive, intermediate, and resistant isolates to metalaxyl were 42.26, 35.98, and 23.53%, respectively. Variations in sensitivities amongst isolates from different areas or different years were very high for metalaxyl. All isolates from Tianlin and Wuxuan were sensitive to metalaxyl, but the metalaxyl-resistant isolates predominated in Tianyang, with the frequency of 51.35%. The EC50 values of certain isolates from Tianyang were higher than 500 μg mL-1 and their resistance levels were over 100000 folds. Cymoxanil has been used for nearly 10 years in Guangxi, and dimethomorph has been used for 5-6 years. However, there was no decrease in sensitivity of P. infestans populations and the sensitivities of the pathogen were nearly normally distributed. Hence, their mean EC50 value [cymoxanil (0.1647±0.0255) μg mL-1, dimethomorph (0.0970±0.0052) μg mL-1] could be used as the baseline sensitivities for monitoring the field resistance development. The comparison with the floating-leaf-disk method indicates that both the techniques provided equivalent results. These studies suggested that metalaxyl can be continuously applied in Tianlin, Wuxuan, and Nanning due to the resistant isolates that have not been found, while for those areas with resistant isolate, the use of metalaxyl should be reduced or alternated, and cymoxanil or dimethomorph was recommended for controlling late blight disease of tomato.

  6. Genome sequence and analysis of the Irish potato famine pathogen Phytophthora infestans

    OpenAIRE

    Haas, Brian J.; Kamoun, Sophien; Michael C Zody; Jiang, Rays H.Y.; Handsaker, Robert E.; Liliana M Cano; Grabherr, Manfred; Kodira, Chinnappa D.; Raffaele, Sylvain; Torto-Alalibo, Trudy; Bozkurt, Tolga O.; Ah-Fong, Audrey M. V.; Alvarado, Lucia; Anderson, Vicky L.; Armstrong, Miles R.

    2009-01-01

    Phytophthora infestans is the most destructive pathogen of potato and a model organism for the oomycetes, a distinct lineage of fungus-like eukaryotes that are related to organisms such as brown algae and diatoms. As the agent of the Irish potato famine in the mid-nineteenth century, P. infestans has had a tremendous effect on human history, resulting in famine and population displacement(1). To this day, it affects world agriculture by causing the most destructive disease of potato, the four...

  7. Phytophthora infestans has a plethora of phospholipase D enzymes including a subclass that has extracellular activity.

    Directory of Open Access Journals (Sweden)

    Harold J G Meijer

    Full Text Available In eukaryotes phospholipase D (PLD is involved in many cellular processes. Currently little is known about PLDs in oomycetes. Here we report that the oomycete plant pathogen Phytophthora infestans has a large repertoire of PLDs divided over six subfamilies: PXPH-PLD, PXTM-PLD, TM-PLD, PLD-likes, and type A and B sPLD-likes. Since the latter have signal peptides we developed a method using metabolically labelled phospholipids to monitor if P. infestans secretes PLD. In extracellular medium of ten P. infestans strains PLD activity was detected as demonstrated by the production of phosphatidic acid and the PLD specific marker phosphatidylalcohol.

  8. Preemergence infection of potato sprouts by Phytophthora infestans in the highland tropics of Ecuador

    DEFF Research Database (Denmark)

    Kromann, Peter; Taipe, Arturo; Andrade-Piedra, Jorge L.

    2008-01-01

    Experiments were conducted to determine whether preemergence infection of potato sprouts by Phytophthora infestans occurs in the highland tropics of Ecuador. In three separate experiments in the field, P. infestans was identified on the preemerged sprouts of 49, 5, and 43% of tubers, respectively...... over 24 h in the field. Deposition had been measured at 1 m from a severely infected potato plot. Our study demonstrated the potential for preemergence infection of potato sprouts by P. infestans in the highlands of Ecuador, where year-round aerial inoculum is present. Preemergence infection...

  9. High genotypic diversity found among population of Phytophthora infestans collected in Estonia.

    Science.gov (United States)

    Runno-Paurson, Eve; Kiiker, Riinu; Joutsjoki, Tiina; Hannukkala, Asko

    2016-03-01

    Potato late blight, caused by the oomycete pathogen Phytophthora infestans, is one of the most important diseases of potato worldwide. This is the first study characterising Estonian P. infestans population using the SSR marker genotyping method. 70 P. infestans isolates collected during the growing season in 2004 from eight potato fields in three different regions of Estonia were characterised with nine polymorphic SSR markers. A1 and A2 mating type isolates were detected from every studied field indicating the high potential for sexual reproduction, which raises the genotypic diversity in P. infestans population. Results revealed highly diverse P. infestans population in Estonia resembling the Northern European populations. Most of the multilocus genotypes were detected only once among the collected isolates. Subpopulations collected from different geographical regions of Estonia showed no differentiation from each other but instead formed one highly diverse group.

  10. 致病疫霉(Phytophthora infestans)对杀菌剂 抗药性研究进展%Advance on fungicides resistance of Phytophthora infestans

    Institute of Scientific and Technical Information of China (English)

    杨志辉; 张志铭; 朱杰华; 赵会欣

    2001-01-01

    综述了致病疫霉(Phytophthora infestans)对内吸性杀菌剂甲霜灵、霜脲氰和保护性杀菌剂代森锰锌和百菌清的抗性研究进展,总结了当前用于防治晚疫病的药剂种类并提出了抗性治理策略。对于致病疫霉抗性遗传研究和抗性治理及药剂防治都具有一定的参考价值。%Progress on the resistance of systemic fungicides (metalaxyl and cymoxanil) and protectant fungicidies ( mancozeb and chlorothalonil) to Phytophthora infestans was reviewed. Fungicides used in controlling late blight were listed and strategies on resistance management were proposed. It might be referred.on resistance inheritance research, resistance management and fungicide control.

  11. Incidence of Phytophthora infestans (Mont.) de Bary on potato and tomato in Maine, 2006-2010

    Science.gov (United States)

    Late blight, caused by Phytophthora infestans, is a devastating disease globally. In Maine, we recorded late blight on potato and tomato during the 2006-2010 cropping seasons. From 2006 to 2008, over 90% of diseased samples were collected in potato fields from northern and central Aroostook County i...

  12. Tuber blight development in potato cultivars in response to different genotypes of Phytophthora infestans

    Science.gov (United States)

    Potato late blight, caused by Phytophthora infestans, is one of the most devastating diseases in potatoes, causing significant loses under disease-conducive conditions. Migrations or introduction of new genotypes to a specific region impose a different set of criteria for consideration for potato gr...

  13. Survival potential of Phytophthora infestans sporangia in relation to meteorological factors

    Science.gov (United States)

    Assessment of meteorological factors coupled with sporangia survival curves may enhance effective management of potato late blight, caused by Phytophthora infestans. We utilized a non-parametric density estimation approach to evaluate the cumulative probability of occurrence of temperature and relat...

  14. The Phytophthora infestans avirulence gene PiaAvr4 and its potato counterpart R4

    NARCIS (Netherlands)

    Poppel, van P.M.J.A.

    2009-01-01

    The potato late blight disease that is caused by the oomycete pathogen Phytophthora infestans is a major threat for potato crops worldwide. In recent years research on oomycete plant pathogens was boosted by the availability of novel genomic tools and resources for several oomycete genera, such as

  15. Durable cisgenic resistance to Phytophthora infestans in potato and perspectives for applications in Africa

    NARCIS (Netherlands)

    Gheysen, G.; Heremans, B.; Droogenbroeck, van B.; Custers, R.; Vossen, J.H.; Visser, R.G.F.; Jacobsen, E.; Hutten, R.C.B.; Haverkort, A.J.

    2015-01-01

    Late blight caused by Phytophthora infestans is a major constraint in potato production. A promising strategy to combat late blight in potato is to combine different resistance genes to achieve durable resistance. Resistance genes from wild relatives can be introduced by breeding or by

  16. Towards the development of integrated cultural control of tomato late blight (Phytophthora infestans) in Uganda

    NARCIS (Netherlands)

    Tumwine, J.

    1999-01-01

    Tomato ( Lycopersicon esculentum ) is a major vegetable crop in Uganda. Moneymaker, Marglobe, Heinz and Roma are the major commercial varieties grown in the country, the first two being the most popular. Late blight ( Phytophthora infestans ) is the most important disease of Ugandan tomatoes. Tomato

  17. Phytophthora infestans has a plethora of phospholipase D enzymes including a subclass that has extracellular activity

    NARCIS (Netherlands)

    Meijer, H.J.G.; Hassen, H.H.; Govers, F.

    2011-01-01

    In eukaryotes phospholipase D (PLD) is involved in many cellular processes. Currently little is known about PLDs in oomycetes. Here we report that the oomycete plant pathogen Phytophthora infestans has a large repertoire of PLDs divided over six subfamilies: PXPH-PLD, PXTM-PLD, TM-PLD, PLD-likes, an

  18. Aggressiveness of Phytophthora infestans on detached potato leaflets in four Nordic countries

    DEFF Research Database (Denmark)

    Lehtinen, A; Andersson, B; Le, V H;

    2009-01-01

    Potato fields in Denmark, Finland, Norway and Sweden were sampled for single-lesion isolates of Phytophthora infestans. The aggressiveness of the isolates was determined on detached leaflets of potato cvs Bintje (susceptible) and Matilda (moderately resistant). The aggressiveness tests were carried...

  19. Stability of resistance to Phytophthora infestans in potato: an international evaluation

    NARCIS (Netherlands)

    Forbes, G.A.; Chacon, M.G.; Kirk, H.G.; Huarte, M.A.; Damme, van M.M.A.; Distel, S.; Mackay, G.R.; Stewart, H.E.; Lowe, R.; Duncan, J.M.; Mayton, H.S.; Fry, W.E.; Andrivon, D.; Ellisseche, D.; Pelle, R.; Platt, H.W.; MacKenzie, G.; Tarn, T.R.; Colon, L.T.; Budding, D.J.; Lozoya-Saldana, H.

    2005-01-01

    Ten institutions in nine countries joined together to test the stability of resistance of 14 potato genotypes to the oomycete pathogen Phytophthora infestans in three separate trials. Seven of the genotypes were tested in one trial involving seven locations, and all 14 were tested in two subsequent

  20. Survival potential of Phytophthora infestans in relation to environmental factors and late blight occurrence

    Science.gov (United States)

    Potato is an important crop globally and late blight (Phytophthora infestans) often results in severe crop loss. The cost for late blight control can be in excess of $210 million in the United States. We utilized a non-parametric density distribution analysis of local temperature (Temp) and relative...

  1. The Phytophthora infestans avirulence gene PiaAvr4 and its potato counterpart R4

    NARCIS (Netherlands)

    Poppel, van P.M.J.A.

    2009-01-01

    The potato late blight disease that is caused by the oomycete pathogen Phytophthora infestans is a major threat for potato crops worldwide. In recent years research on oomycete plant pathogens was boosted by the availability of novel genomic tools and resources for several oomycete genera, such as P

  2. Identification of stable resistance to Phytophthora infestans in potato genotypes evaluated in field experiments in Peru

    DEFF Research Database (Denmark)

    Wulff, Ednar Gadelha; Pérez, W.; Nelson, R.J.;

    2007-01-01

    Abstract: In this study, genotype by environment (G x E) interactions and phenotypic stability of resistance to Phytophthora infestans, the cause of late blight, were analysed in Peru lot 13 potato genotypes, using additive main effects and multiplicative interaction (AMMI) analysis and Huehn's non...

  3. Population structure of Phytophthora infestans in the Toluca Valley region of Central Mexico

    NARCIS (Netherlands)

    Grünwald, N.J.; Flier, W.G.; Sturbaum, A.K.; Garay-Serrano, E.; Bosch, van den G.B.M.; Smart, C.D.; Matuszak, J.M.; Turkensteen, L.J.; Fry, W.E.

    2001-01-01

    We tested the hypothesis that the population of Phytophthora infestans in the Toluca valley region is genetically differentiated according to habitat. Isolates were sampled in three habitats from (i) wild Solanum spp. (WILD), (ii) land-race varieties in low-input production systems (RURAL), and (iii

  4. Resistance to Phytophthora infestans in Solanum tuberosum and wild Solanum species

    NARCIS (Netherlands)

    Colon, L.T.

    1994-01-01

    Resistance to Phytophthora infestans , the causal agent of late blight, is present in the potato, Solanum tuberosum , and in many wild relatives of this crop. The resistance of S. tuberosum is partial and, though helpful in reducing the use of fungicides, is not sufficient to fully solve the problem

  5. Efficient multiplex simple sequence repeat genotyping of the oomycete plant pathogen Phytophthora infestans

    NARCIS (Netherlands)

    Li, Y.; Cooke, D.E.L.; Jacobsen, E.; Lee, van der T.A.J.

    2013-01-01

    Genotyping is fundamental to population analysis. To accommodate fast, accurate and cost-effective genotyping, a one-step multiplex PCR method employing twelve simple sequence repeat (SSR) markers was developed for high-throughput screening of Phytophthora infestans populations worldwide. The SSR

  6. Agrobacterium tumefaciens mediated transformation of the oomycete plant pathogen Phytophthora infestans

    NARCIS (Netherlands)

    Vijn, I.; Govers, F.

    2003-01-01

    Agrobacterium tumefaciens is widely used for plant DNA transformation and, more recently, has also been used to transform yeast and filamentous fungi. Here we present a protocol for Agrobacterium-mediated DNA transformation of the oomycete Phytophthora infestans, the causal agent of potato late blig

  7. Phytophthora infestans avirulence genes: mapping, cloning and diversity in field isolates

    NARCIS (Netherlands)

    Guo, J.

    2008-01-01

    Potato late blight, caused by the oomycete pathogen Phytophthora infestans (Mont.) de Bary, is the most disastrous disease on potato worldwide and also the greatest threat to potato production in China. Loss of yield and quality, and the costs of chemical control of potato late blight account for

  8. Differential expression of G protein alpha and ß subunit genes during development of Phytophthora infestans

    NARCIS (Netherlands)

    Laxalt, A.M.; Latijnhouwers, M.; Hulten, van M.; Govers, F.

    2002-01-01

    A G protein subunit gene (pigpa1) and a G protein subunit gene (pigpb1) were isolated from the oomycete Phytophthora infestans, the causal agent of potato late blight. Heterotrimeric G proteins are evolutionary conserved GTP-binding proteins that are composed of ,, and subunits and participate in di

  9. Identification of potato genes involved in Phytophthora infestans resistance by transposon mutagenesis

    NARCIS (Netherlands)

    Enckevort, van L.J.G.

    2000-01-01

    The late blight disease, caused by the oomycete Phytophthora infestans (Mont.) de Bary, is a serious threat to the potato crop every growing season. This has, for example, led to the disastrous Irish famine in the middle of the 19 th century, and

  10. The Irish potato famine pathogen Phytophthora infestans originated in central Mexico rather than the Andes.

    Science.gov (United States)

    Goss, Erica M; Tabima, Javier F; Cooke, David E L; Restrepo, Silvia; Fry, William E; Forbes, Gregory A; Fieland, Valerie J; Cardenas, Martha; Grünwald, Niklaus J

    2014-06-17

    Phytophthora infestans is a destructive plant pathogen best known for causing the disease that triggered the Irish potato famine and remains the most costly potato pathogen to manage worldwide. Identification of P. infestan's elusive center of origin is critical to understanding the mechanisms of repeated global emergence of this pathogen. There are two competing theories, placing the origin in either South America or in central Mexico, both of which are centers of diversity of Solanum host plants. To test these competing hypotheses, we conducted detailed phylogeographic and approximate Bayesian computation analyses, which are suitable approaches to unraveling complex demographic histories. Our analyses used microsatellite markers and sequences of four nuclear genes sampled from populations in the Andes, Mexico, and elsewhere. To infer the ancestral state, we included the closest known relatives Phytophthora phaseoli, Phytophthora mirabilis, and Phytophthora ipomoeae, as well as the interspecific hybrid Phytophthora andina. We did not find support for an Andean origin of P. infestans; rather, the sequence data suggest a Mexican origin. Our findings support the hypothesis that populations found in the Andes are descendants of the Mexican populations and reconcile previous findings of ancestral variation in the Andes. Although centers of origin are well documented as centers of evolution and diversity for numerous crop plants, the number of plant pathogens with a known geographic origin are limited. This work has important implications for our understanding of the coevolution of hosts and pathogens, as well as the harnessing of plant disease resistance to manage late blight.

  11. Genomic Characterization of a South American Phytophthora Hybrid Mandates Reassessment of the Geographic Origins of Phytophthora infestans.

    Science.gov (United States)

    Martin, Michael D; Vieira, Filipe G; Ho, Simon Y W; Wales, Nathan; Schubert, Mikkel; Seguin-Orlando, Andaine; Ristaino, Jean B; Gilbert, M Thomas P

    2016-02-01

    As the oomycete pathogen causing potato late blight disease, Phytophthora infestans triggered the famous 19th-century Irish potato famine and remains the leading cause of global commercial potato crop destruction. But the geographic origin of the genotype that caused this devastating initial outbreak remains disputed, as does the New World center of origin of the species itself. Both Mexico and South America have been proposed, generating considerable controversy. Here, we readdress the pathogen's origins using a genomic data set encompassing 71 globally sourced modern and historical samples of P. infestans and the hybrid species P. andina, a close relative known only from the Andean highlands. Previous studies have suggested that the nuclear DNA lineage behind the initial outbreaks in Europe in 1845 is now extinct. Analysis of P. andina's phased haplotypes recovered eight haploid genome sequences, four of which represent a previously unknown basal lineage of P. infestans closely related to the famine-era lineage. Our analyses further reveal that clonal lineages of both P. andina and historical P. infestans diverged earlier than modern Mexican lineages, casting doubt on recent claims of a Mexican center of origin. Finally, we use haplotype phasing to demonstrate that basal branches of the clade comprising Mexican samples are occupied by clonal isolates collected from wild Solanum hosts, suggesting that modern Mexican P. infestans diversified on Solanum tuberosum after a host jump from a wild species and that the origins of P. infestans are more complex than was previously thought.

  12. The Plant Membrane-Associated REMORIN1.3 Accumulates in Discrete Perihaustorial Domains and Enhances Susceptibility to Phytophthora infestans1[W

    Science.gov (United States)

    Bozkurt, Tolga O.; Richardson, Annis; Dagdas, Yasin F.; Mongrand, Sébastien; Kamoun, Sophien; Raffaele, Sylvain

    2014-01-01

    Filamentous pathogens such as the oomycete Phytophthora infestans infect plants by developing specialized structures termed haustoria inside the host cells. Haustoria are thought to enable the secretion of effector proteins into the plant cells. Haustorium biogenesis, therefore, is critical for pathogen accommodation in the host tissue. Haustoria are enveloped by a specialized host-derived membrane, the extrahaustorial membrane (EHM), which is distinct from the plant plasma membrane. The mechanisms underlying the biogenesis of the EHM are unknown. Remarkably, several plasma membrane-localized proteins are excluded from the EHM, but the remorin REM1.3 accumulates around P. infestans haustoria. Here, we used overexpression, colocalization with reporter proteins, and superresolution microscopy in cells infected by P. infestans to reveal discrete EHM domains labeled by REM1.3 and the P. infestans effector AVRblb2. Moreover, SYNAPTOTAGMIN1, another previously identified perihaustorial protein, localized to subdomains that are mainly not labeled by REM1.3 and AVRblb2. Functional characterization of REM1.3 revealed that it is a susceptibility factor that promotes infection by P. infestans. This activity, and REM1.3 recruitment to the EHM, require the REM1.3 membrane-binding domain. Our results implicate REM1.3 membrane microdomains in plant susceptibility to an oomycete pathogen. PMID:24808104

  13. SNP-based differentiation of Phytophthora infestans clonal lineages using locked nucleic acid probes and high resolution melt analysis

    Science.gov (United States)

    Phytophthora infestans, the cause of the devastating late blight disease of potato and tomato, exhibits a clonal reproductive lifestyle in North America. Phenotypes such as fungicide sensitivity and host preference are conserved among individuals within clonal lineages, while substantial phenotypic ...

  14. Reproductive strategies of field Phytophthora infestans populations on potato and tomato in some regions of Russia

    Directory of Open Access Journals (Sweden)

    Smirnov A.N.

    2009-01-01

    Full Text Available The occurrence of zoosporangia and oospores is analyzed for 88 field populations of Phytophthora infestans (Mont. de Bary in Moscow region and other regions of Russia from 1997 to 2006. For estimation of zoosporangia and oospore frequencies in the populations, the indexes IZ (for zoosporangia and IO (for oospores are suggested. The combinations of these indexes enabled a reveal of 4 strategies for P. infestans reproduction, which were found in the field populations of the pathogen. These strategies were more numerous in P. infestans field populations on tomato than on potato (4 versus 2 in spite of the fact that potato populations in Moscow region strongly predominated. It was connected with rareness or absence of oospores in potato and their presence in tomato, especially in fruit of many populations. The knowledge about strategies of reproduction can be applied for verification of efficiency of new methods for crop protection against late blight, and for investigations of P. infestans populations.

  15. Fungicide sensitivity of US genotypes of Phytophthora infestans (Mont.) de Bary to six oomycete-targeted compounds.

    Science.gov (United States)

    Phytophthora infestans (Mont.) de Bary causes potato late blight, an important and costly disease of potato and tomato crops. The baseline sensitivity of recent clonal lineages of P. infestans was tested for six oomycete-targeted fungicides. Forty five isolates collected between 2004 and 2012 were t...

  16. Presence of the potato late blight resistance gene RB does not promote adaptive parasitism of phytophthora infestans

    Science.gov (United States)

    The gene RB is derived from the wild potato species S. bulbocastanum and confers partial resistance to late blight, caused by the oomycete pathogen Phytophthora infestans. In order to investigate whether a single strain of P. infestans can adapt to overcome this partial resistance source, we subject...

  17. Large-scale gene discovery in the oomycete Phytophthora infestans reveals likely components of phytopathogenicity shared with true fungi

    NARCIS (Netherlands)

    Randall, T.A.; Dwyer, R.A.; Huitema, E.; Beyer, K.; Cvitanich, C.; Kelkar, H.; Ah Fong, A.M.V.; Gates, K.; Roberts, S.; Yatzkan, E.; Gaffney, T.; Law, M.; Testa, A.; Torto-Alalibo, T.; Zhang Meng,; Zheng Li,; Mueller, E.; Windass, J.; Binder, A.; Birch, P.R.J.; Gisi, U.; Govers, F.; Gow, N.A.; Mauch, F.; West, van P.; Waugh, M.E.; Yu Jun,; Boller, T.; Kamoun, S.; Lam, S.T.; Judelson, H.S.

    2005-01-01

    o overview the gene content of the important pathogen Phytophthora infestans, large-scale cDNA and genomic sequencing was performed. A set of 75,757 high-quality expressed sequence tags (ESTs) from P. infestans was obtained from 20 cDNA libraries representing a broad range of growth conditions, stre

  18. Phenotypic variation within a clonal lineage of Phytophthora infestans infecting both tomato and potato in Nicaragua.

    Science.gov (United States)

    Blandón-Díaz, J U; Widmark, A-K; Hannukkala, A; Andersson, B; Högberg, N; Yuen, J E

    2012-03-01

    Late blight caused by Phytophthora infestans (Mont.) de Bary is a constraint to both potato and tomato crops in Nicaragua. The hypothesis that the Nicaraguan population of P. infestans is genotypically and phenotypically diverse and potentially subdivided based on host association was tested. A collection of isolates was analyzed using genotypic markers (microsatellites and mitochondrial DNA haplotype) and phenotypic markers (mating type, virulence, and fungicide sensitivity). The genotypic analysis revealed no polymorphism in 121 of 132 isolates of P. infestans tested. Only the Ia haplotype and the A2 mating type were detected. Most of the tested isolates were resistant to metalaxyl. The virulence testing showed variation among isolates of P. infestans. No evidence was found of population differentiation among potato and tomato isolates of P. infestans based on the genotypic and phenotypic analysis. We conclude that the Nicaraguan population of P. infestans consists of a single clonal lineage (NI-1) which belongs to the A2 mating type and the Ia mitochondrial DNA haplotype. Moreover, based on the markers used, this population of P. infestans does not resemble the population in countries from which potato seed is imported to Nicaragua or the population in neighboring countries. The data presented here indicate that the NI-1 clonal lineage is the primary pathogen on both potato and tomato, and its success on both host species is unique in a South American context.

  19. Analysis on Genotypic Differentiation of Phytophthora infestans by Using Random Amplified Polymorphic DNA (RAPD)

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A total of 104 isolates including two Korean isolates and three Japanese isolates of Phytophthora infestans collected from Heilongjiang and Jilin Provinces from 2006 to 2008 were used to determine their mating types,metalaxyl resistance,and RAPD genotypes.All the isolates of P.infestans collected from Heilongjiang and Jilin Provinces belonged to A 1 mating type,and no A 2 mating type was detected.Frequencies of metalaxyl resistant isolates were 94.4%,47.8% and 75.0% in 2006,2007 and 2008,respectively.Accord...

  20. The in vitro culture of Phytophthora infestans isolates occurring on the tomato - their pathogenicity and usefulness for artificial inoculations

    Directory of Open Access Journals (Sweden)

    Elżbieta Horodecka

    2013-12-01

    Full Text Available In investigations on the fungus, Phytophthora infestans, isolated from open air, field-grown tomatoes, particular attention was paid to the pathogenicity of 32 isolates and the suitability of 10 kinds of natural media. It is concluded that Phytophthora races in Poland have highly varied pathogenicities and that they belong to race 0 or 1. The races were divided into subgroups of various aggressiveness. It was found that the best medium to obtain an inoculum was the agar-oat medium without vitamin B1. Vitamin B1 as well as tomatine added to agar media stimulated growth, but inhibited sporulation of Phytophthora infestans.

  1. Race Structure and Distribution of Phytophthora infestans in the Investigated Areas of China

    Institute of Scientific and Technical Information of China (English)

    ZHU Jie-hua; YANG Zhi-hui; SHAO Tie-mei; TIAN Shi-min; ZHANG Zhi-ming

    2003-01-01

    Ninety isolates collected from five different provinces and cities (Hebei, Yunan, Sichuan,Chongqing, Inner Mongolia ) during 1997 -1998 were tested with potato clones possessed 8 dominant mono-genes R1, R3, R4, R6, R7, R9, R10, R11 and the combination of R1-R4 of the international late blight dif-ferential host. It concluded that: (1) in the 90 isolates tested 21 different races were detected, of which the 1.3. 4. 7. 9. 10. 11 was very common with frequency of 32.2%, followed by 1. 3. 4. 6. 7. 9. 10. 11 and 3.4. 7. 9. 11 with frequency of 10.0%; (2) all tested resistant genes were compatible to the virulent gene of iso-lates of Phytophthora infestans assayed, which indicated that the virulent genes were very common in thetested population of Phytophthora infestans.

  2. Spatial analysis of the incidence of Phytophthora infestans (Mont. De Bary and Phytophthora nicotianae Breda de Haan on potato

    Directory of Open Access Journals (Sweden)

    Leónides Castellanos González

    2016-03-01

    Full Text Available The objective of this research was to conduct a spatial analysis of the incidence of Phytophthora nicotianae Breda de Haan and Phytophthora infestans (Mont. De Bary, during five seasons of potato in Fields Company Miscellaneous Crops in Horquita, Cienfuegos (2003-2004 to 2007-2008. Information about pathogens, collected by the Plant Protection Station of Yaguaramas, was used in order to do so. An alpha numerical database was made, oriented to a group of areas under center pivot irrigation machines (Kubans and Bayamón and its quadrants. Parallel to this, mapping of center pivot machines and quadrants was generated in MapInfo GIS 8.5. Several automatic geo codifications were made in order to relate the alphanumeric database and the mapping, and thematic maps were generated in the presence or absence of pathogens. The two study agents have presented high spatial variability during the five planting seasons. Both have influenced the same geographical area with similar appearance date. P. infestans has not expressed a defined dispersion pattern and it has spread at random from the primary source of incidence, while Phytophthora nicotianae has become an endemic agent which shows a dispersion pattern towards neighboring areas or areas connected by the road network from the primary sources, which have been associated with poor land leveling and late or intermediate planting seasons.

  3. Mitochondrial DNA assessment of Phytophthora infestans isolates from potato and tomato in Ethiopia reveals unexpected diversity.

    Science.gov (United States)

    Shimelash, Daniel; Hussien, Temam; Fininsa, Chemeda; Forbes, Greg; Yuen, Jonathan

    2016-08-01

    Mitochondrial DNA (mtDNA) haplotypes were determined using restriction fragment length polymorphism (RFLP) for P. infestans sampled from 513 foliar lesions of late blight found on potato and tomato in different regions of Ethiopia. Among the four reported mitochondrial haplotypes of Phytophthora infestans, Ia, Ib and IIb were detected in 93 % of the samples analyzed but the vast majority of these were Ia. The remaining 7 % represented a previously unreported haplotype. DNA sequencing of this new haplotype also confirmed a single base nucleotide substitution that resulted in loss of EcoRI restriction site and gain of two additional MspI sites in cox1 and atp1 genes, respectively. There were 28 polymorphic sites among all nucleotide sequences including five reference isolates. Sites with alignment gaps were observed in P4 with one nucleotide deletion in 11 Ethiopian isolates. None of the reference sequence produced frame-shifts, with the exception of the 3-nucleotide deletion in the P4 region by Phytophthora andina, a feature that can be used to distinguish the new Ethiopian isolates from P. andina. While a distinguishing molecular data presented here clearly separated them from P. infestans, 7 % of the isolates that share this feature formed an important component of the late blight pathogen causing disease on Solanum tuberosum in Ethiopia. Thus, these Ethiopian isolates could represent a novel Phytophthora species reported for the first time here.

  4. Resistance to Phytophthora infestans EC-1 clonal lineage in Solanum tuberosum by introducing the RB gene

    Directory of Open Access Journals (Sweden)

    María Lupe Román

    2015-04-01

    Full Text Available 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.

  5. Phylogenetic relationships of Phytophthora andina, a new species from the highlands of Ecuador that is closely related to the Irish potato famine pathogen Phytophthora infestans.

    Science.gov (United States)

    Gómez-Alpizar, Luis; Hu, Chia-Hui; Oliva, Ricardo; Forbes, Gregory; Ristaino, Jean Beagle

    2008-01-01

    Phylogenetic relationships of Phytophthora infestans sensu lato in the Andean highlands of South America were examined. Three clonal lineages (US-1, EC-1, EC-3) and one heterogeneous lineage (EC-2) were found in association with different host species in genus Solanum. The EC-2 lineage includes two mitochondrial (mtDNA) haplotypes, Ia and Ic. Isolates of P. infestans sensu lato EC-2 fit the morphological description of P. infestans but are different from any genotypes of P. infestans described to date. All isolates of P. infestans sensu lato from Ecuador were amplified by a P. infestans specific primer (PINF), and restriction fragment length patterns were identical in isolates amplified with ITS primers 4 and 5. The EC-1 clonal lineage of P. infestans sensu lato from S. andreanum, S. columbianum, S. paucijugum, S. phureja, S. regularifolium, S. tuberosum and S. tuquerense was confirmed to be P. infestans based on sequences of the cytochrome oxidase I (cox I) gene and intron 1 of ras gene. The EC-2 isolates with the Ic haplotype formed a distinct branch in the same clade with P. infestans and P. mirabilis, P. phaseoli and P. ipomoeae for both cox I and ras intron 1 phylogenies and were identified as the newly described species P. andina. Ras intron 1 sequence data suggests that P. andina might have arisen via hybridization between P. infestans and P. mirabilis.

  6. Contrasting Potato Foliage and Tuber Defense Mechanisms against the Late Blight Pathogen Phytophthora infestans.

    Directory of Open Access Journals (Sweden)

    Liangliang Gao

    Full Text Available The late blight pathogen Phytophthora infestans can attack both potato foliage and tubers. When inoculated with P. infestans, foliage of nontransformed 'Russet Burbank' (WT develops late blight disease while that of transgenic 'Russet Burbank' line SP2211 (+RB does not. We compared the foliar transcriptome responses of these two lines to P. infestans inoculation using an RNA-seq approach. A total of 515 million paired end RNA-seq reads were generated, representing the transcription of 29,970 genes. We also compared the differences and similarities of defense mechanisms against P. infestans in potato foliage and tubers. Differentially expressed genes, gene groups and ontology bins were identified to show similarities and differences in foliage and tuber defense mechanisms. Our results suggest that R gene dosage and shared biochemical pathways (such as ethylene and stress bins contribute to RB-mediated incompatible potato-P. infestans interactions in both the foliage and tubers. Certain ontology bins such as cell wall and lipid metabolisms are potentially organ-specific.

  7. Structural and functional profile of the carbohydrate esterase gene complement in Phytophthora infestans.

    Science.gov (United States)

    Ospina-Giraldo, Manuel D; McWalters, Jessica; Seyer, Lauren

    2010-12-01

    The plant cell cuticle is the first obstacle for penetration of the host by plant pathogens. To breach this barrier, most pathogenic fungi employ a complex assortment of cell wall-degrading enzymes including carbohydrate esterases, glycoside hydrolases, and polysaccharide lyases. We characterized the full complement of carbohydrate esterase-coding genes in three Phytophthora species and analyzed the expression of cutinase in vitro and in planta; we also determined the cutinase allele distribution in multiple isolates of P. infestans. Our investigations revealed that there are 49, 21, and 37 esterase homologs in the P. infestans, P. ramorum, and P. sojae genomes, respectively, with a considerable number predicted to be extracellular. Four cutinase gene copies were found in both the P. infestans and P. ramorum genomes, while 16 copies were found in P. sojae. Transcriptional analyses of cutinase in P. infestans revealed that its expression level during infection is significantly upregulated at all time points compared to that of the same gene in mycelium grown in vitro. Expression achieves maximum values at 15 hpi, declining at subsequent time points. These results may suggest, therefore, that cutinase most likely plays a role in P. infestans pathogenicity.

  8. MiR1918 enhances tomato sensitivity to Phytophthora infestans infection.

    Science.gov (United States)

    Luan, Yushi; Cui, Jun; Wang, Weichen; Meng, Jun

    2016-10-25

    Late blight of tomato is caused by the oomycete pathogen Phytophthora infestans. In our previous work, we identified and characterized a miR1918 in P. infestans (pi-miR1918), and showed that its sequence is similar to the sequence of tomato miR1918 (sly-miR1918). In this study, we used Arabidopsis thaliana pre-miR159a as a backbone to synthesize pi-miR1918 via PCR and mutagenesis. The artificial pi-miR1918 was used to investigate the role of miR1918 in tomato-P. infestans interaction. Trangenic tomato plants that overexpressed the artificial pi-miR1918 displayed more serious disease symptoms than wild-type tomato plants after infection with P. infestans, as shown by increased number of necrotic cells, lesion sizes and number of sporangia per leaf. The target genes of pi-miR1918 and sly-miR1918 were also predicted for tomato and P. infestans, respectively. qPCR analysis of these targets also performed during tomato-P. infestans interaction. The expression of target gene, RING finger were negatively correlated with miR1918 in the all Lines of transgenic tomato plants. In addition, we used the 5' RACE to determine the cleavage site of miR1918 to RING finger. These results suggested that miR1918 might be involved in the silencing of target genes, thereby enhancing the susceptibility of tomato to P. infestans infection.

  9. The transcriptome of compatible and incompatible interactions of potato (Solanum tuberosum with Phytophthora infestans revealed by DeepSAGE analysis.

    Directory of Open Access Journals (Sweden)

    Gabor Gyetvai

    Full Text Available Late blight, caused by the oomycete Phytophthora infestans, is the most important disease of potato (Solanum tuberosum. Understanding the molecular basis of resistance and susceptibility to late blight is therefore highly relevant for developing resistant cultivars, either by marker-assissted selection or by transgenic approaches. Specific P. infestans races having the Avr1 effector gene trigger a hypersensitive resistance response in potato plants carrying the R1 resistance gene (incompatible interaction and cause disease in plants lacking R1 (compatible interaction. The transcriptomes of the compatible and incompatible interaction were captured by DeepSAGE analysis of 44 biological samples comprising five genotypes, differing only by the presence or absence of the R1 transgene, three infection time points and three biological replicates. 30,859 unique 21 base pair sequence tags were obtained, one third of which did not match any known potato transcript sequence. Two third of the tags were expressed at low frequency (<10 tag counts/million. 20,470 unitags matched to approximately twelve thousand potato transcribed genes. Tag frequencies were compared between compatible and incompatible interactions over the infection time course and between compatible and incompatible genotypes. Transcriptional changes were more numerous in compatible than in incompatible interactions. In contrast to incompatible interactions, transcriptional changes in the compatible interaction were observed predominantly for multigene families encoding defense response genes and genes functional in photosynthesis and CO(2 fixation. Numerous transcriptional differences were also observed between near isogenic genotypes prior to infection with P. infestans. Our DeepSAGE transcriptome analysis uncovered novel candidate genes for plant host pathogen interactions, examples of which are discussed with respect to possible function.

  10. Arabidopsis late blight: infection of a nonhost plant by Albugo laibachii enables full colonization by Phytophthora infestans.

    Science.gov (United States)

    Belhaj, Khaoula; Cano, Liliana M; Prince, David C; Kemen, Ariane; Yoshida, Kentaro; Dagdas, Yasin F; Etherington, Graham J; Schoonbeek, Henk-Jan; van Esse, H Peter; Jones, Jonathan D G; Kamoun, Sophien; Schornack, Sebastian

    2017-01-01

    The oomycete pathogen Phytophthora infestans causes potato late blight, and as a potato and tomato specialist pathogen, is seemingly poorly adapted to infect plants outside the Solanaceae. Here, we report the unexpected finding that P. infestans can infect Arabidopsis thaliana when another oomycete pathogen, Albugo laibachii, has colonized the host plant. The behaviour and speed of P. infestans infection in Arabidopsis pre-infected with A. laibachii resemble P. infestans infection of susceptible potato plants. Transcriptional profiling of P. infestans genes during infection revealed a significant overlap in the sets of secreted-protein genes that are induced in P. infestans upon colonization of potato and susceptible Arabidopsis, suggesting major similarities in P. infestans gene expression dynamics on the two plant species. Furthermore, we found haustoria of A. laibachii and P. infestans within the same Arabidopsis cells. This Arabidopsis-A. laibachii-P. infestans tripartite interaction opens up various possibilities to dissect the molecular mechanisms of P. infestans infection and the processes occurring in co-infected Arabidopsis cells.

  11. Changes in oxylipin synthesis after Phytophthora infestans infection of potato leaves do not correlate with resistance.

    Science.gov (United States)

    Fauconnier, Marie-Laure; Rojas-Beltran, Jorge; Dupuis, Brice; Delaplace, Pierre; Frettinger, Patrick; Gosset, Virginie; du Jardin, Patrick

    2008-01-01

    Oxylipins constitute a class of molecules notably involved in host-pathogen interactions. In the potato-Phytophthora infestans (Mont.) De Barry (P. infestans) relationships, the role of colneleic and colnelenic acids, two oxylipins resulting from the consecutive action of lipoxygenase (EC 1.13.11.12) and divinyl ether synthase (EC 1.-) on respectively linoleic and linolenic acids have been previously reported. In the present paper, five potato cultivars with contrasting resistance to P. infestans were submitted to infection. Lipoxygenase pathway response was studied at both transcriptional and metabolic levels. A Northern blot preliminary study revealed that lipoxygenase (lox1 and lox3) and divinyl ether synthase genes were clearly up-regulated 96h after leaf inoculation with P. infestans. Profiling of free and esterified oxylipins performed 24h, 48h, 72h and 96h after inoculation, showed that esterified oxylipins are mainly produced with 9-derivatives in higher concentrations (esterified forms of colnelenic acid, 9-hydroxy octadecatrienoic acid, 9-hydroperoxy octadecatrienoic acid). Oxylipin accumulation is undetectable 24h after infection, slightly detectable after 48h, reaching highest concentrations after 96h. Cultivars show slightly different oxylipin profiles but the concentration of individual oxylipins differs markedly 96h after infection. No correlation was found between P. infestans resistance levels and oxylipin synthesis rates or concentration. To assess local and systemic effects of colneleic acid application before P. infestans infection, Bintje cultivar was sprayed with colneleic acid 72h before inoculation. Both application modes (local and systemic) resulted in lipoxygenase pathway activation without affecting the resistance level to the pathogen.

  12. Genotypic diversity and migration patterns of Phytophthora infestans in the Nordic countries.

    Science.gov (United States)

    Sjöholm, Lina; Andersson, Björn; Högberg, Nils; Widmark, Anna-Karin; Yuen, Jonathan

    2013-10-01

    In this study we investigated the genotypic diversity and the migration patterns of Phytophthora infestans in the Nordic countries. Isolates of P. infestans from outbreaks in 43 fields sampled in 2008 were collected using stratified sampling with country, field, and disease foci as the different strata. Microsatellites were used as markers to determine the genotypic variation in the sampled material. The results show a high genotypic variation of P. infestans in the Nordic countries with most of the genotypes found only once among the collected isolates. The major part of the genotypic variation was observed within the fields, with low differentiation between the fields. The observed low association of alleles among loci is consistent with frequent sexual reproduction of P. infestans in the Nordic countries. Coalescence analyses did not support a single common population for the four countries, thus indicating some degree of geographic differentiation. The analyses of migration patterns showed differing levels of gene flow among the Nordic countries. No correlation between migration rates and geographical distance could be seen. This could be explained by different degrees of genetic similarity between the pathogen populations in the different countries.

  13. Screening of novel microorganisms for biosurfactant and biocontrol activity against Phytophthora infestans.

    Science.gov (United States)

    Tomar, Sonica; Singh, B P; Lal, Mehi; Ma, Khan; Hussain, Touseef; Sharma, Sanjeev; Kaushik, S K; Kumar, Satish

    2014-09-01

    In the present study, 95 isolates of bacteria were tested for their biosurfactant as well as biocontrol activity against Phytophthora infestans. The results revealed that only 15.8% isolates showed biosurfactant activity. The emulsification index ranged from 0-68% and 24.2% isolates showed positive reaction for biosurfactant properties. In emulsification assay and oil spreading test, 18.95% and 5.26% isolates, respectively scored positive for biosurfactant production. Among all, only five isolates were found effective against P. infestans, for biocontrol properties. Pseudomonas aeruginosa-1 showed 62.22% inhibition zone after 72 hrs while P. aeruginosa-3 showed 46.42%. Forty-eight hrs old culture supernatants were highly effective in food-poisoning test, tuber slice test and detached leaf method against P. infestans. In whole potato plant test, bacterial cell based formulation, culture supernatant and bacterial cell suspension of P. aeruginosa-1 showed 10.42%, 9.94% and 17.96% diseases severity respectively, as against 53.96% in control. This isolate holds promise as biological control agent against P. infestans in field.

  14. Toxicity of metalaxyl, azoxystrobin, dimethomorph, cymoxanil, zoxamide and mancozeb to Phytophthora infestans isolates from Serbia.

    Science.gov (United States)

    Rekanović, Emil; Potočnik, Ivana; Milijašević-Marčić, Svetlana; Stepanović, Miloš; Todorović, Biljana; Mihajlović, Milica

    2012-01-01

    A study of the in vitro sensitivity of 12 isolates of Phytophthora infestans to metalaxyl, azoxystrobin, dimethomorph, cymoxanil, zoxamide and mancozeb, was conducted. The isolates derived from infected potato leaves collected at eight different localities in Serbia during 2005-2007. The widest range of EC(50) values for mycelial growth of the isolates was recorded for metalaxyl. They varied from 0.3 to 3.9 μg mL(-1) and were higher than those expected in a susceptible population of P. infestans. The EC(50) values of the isolates were 0.16-0.30 μg mL(-1) for dimethomorph, 0.27-0.57 μg mL(-1) for cymoxanil, 0.0026-0.0049 μg mL(-1) for zoxamide and 2.9-5.0 μg mL(-1) for mancozeb. The results indicated that according to effective concentration (EC(50)) the 12 isolates of P. infestans were sensitive to azoxystrobin (0.019-0.074 μg mL(-1)), and intermediate resistant to metalaxyl, dimethomorph and cymoxanil. According to resistance factor, all P. infestans isolates were sensitive to dimethomorph, cymoxanil, mancozeb and zoxamide, 58.3% of isolates were sensitive to azoxystrobin and 50% to metalaxyl. Gout's scale indicated that 41.7% isolates were moderately sensitive to azoxystrobin and 50% to metalaxyl.

  15. Identification of stable resistance to Phytophthora infestans in potato genotypes evaluated in field experiments in Peru

    DEFF Research Database (Denmark)

    Wulff, Ednar Gadelha; Pérez, W.; Nelson, R.J.;

    2007-01-01

    -parametric test. The potato genotypes were tested in seven experiments over two years in the vicinity of Comas, Peru, an area used by the International potato Center to screen for resistance to late blight. Results of the two analyses generally correlated and indicated that quantitative resistance to P. infestans......Abstract: In this study, genotype by environment (G x E) interactions and phenotypic stability of resistance to Phytophthora infestans, the cause of late blight, were analysed in Peru lot 13 potato genotypes, using additive main effects and multiplicative interaction (AMMI) analysis and Huehn's non...... yearly means of the relative area under the disease progress curve (rAUDPC), genotypes could be assigned to one of three resistance categories, resistant, moderately resistant or Susceptible, but the need for a more readily applicable and truly quantitative scale for resistance was noted. Based...

  16. Biochemical contents of pepper seedlings inoculated with phytophthora infestans and arbuscular mycorrhiza

    Directory of Open Access Journals (Sweden)

    Odebode A.C.

    2004-01-01

    Full Text Available The effect of interactions between Arbuscular Glomus etunicatum and fungus Phytophthora infestans on biochemical contents of pepper plants was investigated in a greenhouse experiment. The sugar contents (i.e. Glucose fructose and sucrose were higher in the control and mycorrhizal inoculated pepper seedlings and the lowest in pathogen inoculated seedlings. Free amino acids were the highest in the simultaneously inoculated pepper seedlings while total phenol was found to be the highest in pepper seedlings inoculated with P. infestans. The levels of nitrogen, phosphorus and potassium varied in the inoculated pepper seedlings without any significant difference in the treatment. The results obtained suggest protective influence of mycorrhiza by enhancing the nutritional status of the inoculated pepper seedlings.

  17. Heterokaryotic nuclear conditions and a heterogeneous nuclear population are observed by flow cytometry in Phytophthora infestans.

    Science.gov (United States)

    Catal, Mursel; King, Louis; Tumbalam, Pavani; Wiriyajitsomboon, Prissana; Kirk, William W; Adams, Gerard C

    2010-08-01

    A simple and reliable method for preparation of whole nuclei of a common oomycete, Phytophthora infestans, is described for laser flow cytometry. The ease of preparation, the absence of detectable debris and aggregates, and the precision in determinations of DNA content per nucleus improve interpretation and understanding of the genetics of the organism. Phytophthora infestans is the pathogen that causes potato and tomato late blight. The genetic flexibility of P. infestans and other oomycete pathogens has complicated understanding of the mechanisms of variation contributing to shifts in race structure and virulence profiles on important agricultural crops. Significant phenotypic and genotypic changes are being reported in the apparent absence of sexual recombination in the field. Laser flow cytometry with propidium iodide is useful in investigating the nuclear condition of the somatic colony of field strains of P. infestans. The majority of the studied strains contain a single population of nuclei in nonreplicated diplophase. However, mean DNA content per nucleus varies considerably among isolates confirming the heterogeneity of the nuclear population in regard to C-value, for field isolates. Nuclear DNA content varies from 1.75x to 0.75x that of nuclei in a standard strain from central Mexico. Some strains contain two to three populations of nuclei with differing DNA contents in the mycelium and are heterokaryons. Such a range in DNA content suggests DNA-aneuploidy, but direct confirmation of aneuploidy will require microscopy of chromosomes. Heterokaryosis and populations of nuclei of differing DNA content necessarily confound standardized assays used worldwide in crop breeding programs for determination of race profiles and virulence phenotypes of this important pathogen.

  18. Stage-specific gene expression during sexual development in Phytophthora infestans

    DEFF Research Database (Denmark)

    Fabritius, Anna-Liisa; Cvitanich, Cristina; Judelson, Howard S.

    2002-01-01

    Eight genes that are upregulated during sexual development in the heterothallic oomycete, Phytophthora infestans, were identified by suppression subtractive hybridization. Two genes showed very low but detectable expression in vegetative hyphae and became induced about 40- to >100-fold early...... in mating, before gametangial initials appeared. The remaining six loci were not induced until later in mating, coincident with the formation of gametangia and oospores, with induction levels ranging from 60- to >100-fold. Five genes were single copy, and three were members of families. Sequence analysis...

  19. The kinome of Phytophthora infestans reveals oomycete-specific innovations and links to other taxonomic groups

    Directory of Open Access Journals (Sweden)

    Ah-Fong Audrey MV

    2010-12-01

    Full Text Available Abstract Background Oomycetes are a large group of economically and ecologically important species. Its most notorious member is Phytophthora infestans, the cause of the devastating potato late blight disease. The life cycle of P. infestans involves hyphae which differentiate into spores used for dispersal and host infection. Protein phosphorylation likely plays crucial roles in these stages, and to help understand this we present here a genome-wide analysis of the protein kinases of P. infestans and several relatives. The study also provides new insight into kinase evolution since oomycetes are taxonomically distant from organisms with well-characterized kinomes. Results Bioinformatic searches of the genomes of P. infestans, P. ramorum, and P. sojae reveal they have similar kinomes, which for P. infestans contains 354 eukaryotic protein kinases (ePKs and 18 atypical kinases (aPKs, equaling 2% of total genes. After refining gene models, most were classifiable into families seen in other eukaryotes. Some ePK families are nevertheless unusual, especially the tyrosine kinase-like (TKL group which includes large oomycete-specific subfamilies. Also identified were two tyrosine kinases, which are rare in non-metazoans. Several ePKs bear accessory domains not identified previously on kinases, such as cyclin-dependent kinases with integral cyclin domains. Most ePKs lack accessory domains, implying that many are regulated transcriptionally. This was confirmed by mRNA expression-profiling studies that showed that two-thirds vary significantly between hyphae, sporangia, and zoospores. Comparisons to neighboring taxa (apicomplexans, ciliates, diatoms revealed both clade-specific and conserved features, and multiple connections to plant kinases were observed. The kinome of Hyaloperonospora arabidopsidis, an oomycete with a simpler life cycle than P. infestans, was found to be one-third smaller. Some differences may be attributable to gene clustering, which

  20. Plant-mediated gene silencing restricts growth of the potato late blight pathogen Phytophthora infestans.

    Science.gov (United States)

    Jahan, Sultana N; Åsman, Anna K M; Corcoran, Pádraic; Fogelqvist, Johan; Vetukuri, Ramesh R; Dixelius, Christina

    2015-05-01

    Phytophthora infestans is an oomycete that causes severe damage to potato, and is well known for its ability to evolve rapidly in order to overcome resistant potato varieties. An RNA silencing strategy was evaluated here to clarify if small interfering RNA homologous to selected genes in P. infestans could be targeted from the plant host to reduce the magnitude of the infection. As a proof-of-concept, a hairpin RNA (hp-RNA) construct using the GFP marker gene was designed and introduced in potato. At 72 hpi, a 55-fold reduction of the signal intensity of a corresponding GFP expressing P. infestans strain on leaf samples of transgenic plants, compared with wild-type potato, was detected. This suggests that an RNA interference construct in the potato host could be processed and target a transcript of the pathogen. Three genes important in the infection process of P. infestans, PiGPB1, PiCESA2, and PiPEC, together with PiGAPDH taking part in basic cell maintenance were subsequently tested using an analogous transgenic strategy. Out of these gene candidates, the hp-PiGPB1 targeting the G protein β-subunit (PiGPB1) important for pathogenicity resulted in most restricted disease progress. Further, Illumina sequencing of inoculated transgenic potato leaves revealed sRNAs of 24/25 nt size homologous to the PiGPB1 gene in the transgenic plants indicating post-transcriptional silencing of the target gene. The work demonstrates that a host-induced gene-silencing approach is functional against P. infestans but is highly dependent on target gene for a successful outcome. This finding broadens the arsenal of control strategies to this important plant disease.

  1. Assessment of SIMBLIGHT1, SIMPHYT1, and NOBLIGHT models for predicting Phytophthora infestans in the northeastern U.S.

    Science.gov (United States)

    Accurate prediction of Phytophthora infestans outbreaks is crucial for effective late blight management. The SIMBLIGHT1, SIMPHYT1, and modified SIMPHYT1 models were assessed for predicting late blight outbreaks relative to the NOBLIGHT model using climatic data from field experiments at Presque Isle...

  2. Genetic variation within clonal lineages of Phytophthora infestans revealed through genotyping-by-sequencing, and implications for late blight epidemiology

    Science.gov (United States)

    Genotyping-by-sequencing (GBS) was performed on 257 Phytophthora infestans isolates belonging to four clonal lineages to study within-lineage diversity. The four lineages used in the study included US-8 (n=28), US-11 (n=27), US-23 (n=166), and US-24 (n=36), with isolates originating from 23 of the U...

  3. Effectiveness of SIMBLIGHT1 and SIMPHYT1 models for predicting Phytophthora infestans in the Northeastern United States

    Science.gov (United States)

    Accurate prediction of Phytophthora infestans outbreaks is crucial for effective late blight management. The SIMBLIGHT1, SIMPHYT1, and modified SIMPHYT1 models were assessed for predicting late blight outbreaks relative to the NOBLIGHT model using climatic data from field experiments at Presque Isle...

  4. Identification of a resistance gene Rpi-dlc1 to Phytophthora infestans in European accessions of Solanum dulcamara

    NARCIS (Netherlands)

    Golas, T.M.; Sikkema, A.; Gros, J.; Feron, R.M.C.; Berg, van den R.G.; Weerden, van der G.M.; Mariani, C.; Allefs, J.J.H.M.

    2010-01-01

    Initial screening of 14 Solanum dulcamara accessions enabled the identification of individuals resistant and susceptible to Phytophthora infestans. Crosses between contrasting genotypes resulted in three F2–BC1 populations segregating for resistance to late blight in a laboratory assay and under fie

  5. Formation, production and viability of oospores of Phytophthora infestans from potato and Solanum demissum in the Toluca Valley, central Mexico

    NARCIS (Netherlands)

    Flier, W.G.; Grünwald, N.J.; Fry, W.E.; Turkensteen, L.J.

    2001-01-01

    Aspects of the ecology of oospores of Phytophthora infestans were studied in the highlands of central Mexico. From an investigation of a random sample of strains, it was found that isolates differed in their average capability to form oospores when engaged in compatible pairings. Most crosses produc

  6. Phytophthora infestans field isolates from Gansu Province, China are genetically highly diverse and show a high frequency of self fertility

    NARCIS (Netherlands)

    Han, M.; Liu, G.; Li, J.P.; Govers, F.; Zhu, X.Q.; Shen, C.Y.; Guo, L.Y.

    2013-01-01

    The genetic diversity of 85 isolates of Phytophthora infestans collected in 2007 from Gansu province in China was determined and compared with 21 isolates collected before 2004. Among them, 70 belonged to the A1 mating type and 15 were self-fertile (SF). The mitochondrial DNA haplotypes revealed

  7. Downstream targets of the Phytophthora infestans G alpha subunit PiGPA1 revealed by cDNA-AFLP

    NARCIS (Netherlands)

    Dong, W.; Latijnhouwers, M.; Jiang, R.H.Y.; Meijer, H.J.G.; Govers, F.

    2004-01-01

    In many plant pathogens heterotrimeric G-proteins are essential signalling components involved in development and pathogenicity. In the late blight oomycete pathogen Phytophthora infestans the G-protein (x subunit PiGPA1 controls zoospore motility and is required for virulence. To identify G-protein

  8. Phytophthora infestans isolates lacking class I ipiO variants are virulent on Rpi-blb1 potato

    NARCIS (Netherlands)

    Champouret, N.; Bouwmeester, K.; Rietman, H.; Lee, van der T.; Maliepaard, C.A.; Heupink, A.; Vondervoort, van de P.J.I.; Jacobsen, E.; Visser, R.G.F.; Vossen, van der E.A.G.; Govers, F.; Vleeshouwers, V.G.A.A.

    2009-01-01

    A strategy to control the devastating late blight disease is providing potato cultivars with genes that are effective in resistance to a broad spectrum of Phytophthora infestans isolates. Thus far, most late blight resistance (R) genes that were introgressed in potato were quickly defeated. In contr

  9. Genetic diversity of Phytophthora infestans sensu lato in Ecuador provides new insight into the origin of this important plant pathogen

    NARCIS (Netherlands)

    Adler, N.E.; Erselius, L.J.; Chacón, G.M.; Flier, W.G.; Ordonez, M.E.; Kroon, L.P.N.M.; Forbes, G.A.

    2004-01-01

    The metapopulation structure of Phytophthora infestans sensu lato is genetically diverse in the highlands of Ecuador. Previous reports documented the diversity associated with four putative clonal lineages of the pathogen collected from various hosts in the genus Solanum. This paper simultaneously a

  10. Impacts of climate change on the first occurrence of the Light blight (Phytophthora infestans (Mont. de Bary 1876

    Directory of Open Access Journals (Sweden)

    Zdeněk Žalud

    2008-01-01

    Full Text Available The increase in the infestation pressure of various pathogens will be one the most important factors limiting the crop production under the future climate conditions. Weather driven NegFry model has been used for estimating future Phytophthora infestans occurrence at four experimental potato stations of the State Institute for Agriculture Supervision and Testing. Both the infestation dates of Phytophthora infestans occurrence and the shape of the critical number curve were analyzed using observed weather data as well as datasets constructed according to four climate change scenarios that were based on two global circulation models. The results show the shift of the infestation pressure to the beginning of the year and describe increasing trend of critical number reaching to detecting of the first Phyto­phtho­ra infestans occurrence for 2025 and 2050. Scenarios created according to HadCM and SRES – A2 seem to be more suitable for disease development.

  11. Effect of Flumorph on F-Actin Dynamics in the Potato Late Blight Pathogen Phytophthora infestans.

    Science.gov (United States)

    Hua, Chenlei; Kots, Kiki; Ketelaar, Tijs; Govers, Francine; Meijer, Harold J G

    2015-04-01

    Oomycetes are fungal-like pathogens that cause notorious diseases. Protecting crops against oomycetes requires regular spraying with chemicals, many with an unknown mode of action. In the 1990s, flumorph was identified as a novel crop protection agent. It was shown to inhibit the growth of oomycete pathogens including Phytophthora spp., presumably by targeting actin. We recently generated transgenic Phytophthora infestans strains that express Lifeact-enhanced green fluorescent protein (eGFP), which enabled us to monitor the actin cytoskeleton during hyphal growth. For analyzing effects of oomicides on the actin cytoskeleton in vivo, the P. infestans Lifeact-eGFP strain is an excellent tool. Here, we confirm that flumorph is an oomicide with growth inhibitory activity. Microscopic analyses showed that low flumorph concentrations provoked hyphal tip swellings accompanied by accumulation of actin plaques in the apex, a feature reminiscent of tips of nongrowing hyphae. At higher concentrations, swelling was more pronounced and accompanied by an increase in hyphal bursting events. However, in hyphae that remained intact, actin filaments were indistinguishable from those in nontreated, nongrowing hyphae. In contrast, in hyphae treated with the actin depolymerizing drug latrunculin B, no hyphal bursting was observed but the actin filaments were completely disrupted. This difference demonstrates that actin is not the primary target of flumorph.

  12. A potato pathogenesis-related protein gene, StPRp27, contributes to race-nonspecific resistance against Phytophthora infestans.

    Science.gov (United States)

    Shi, Xiaolei; Tian, Zhendong; Liu, Jun; van der Vossen, Edwin A G; Xie, Conghua

    2012-02-01

    Late blight caused by Phytophthora infestans is the most important disease of potato. Many efforts have been made to understand molecular mechanism of the durable resistance to address the challenge raised by rapid evolution of the pathogen. A pathogenesis related protein (PR) gene StPRp27 was previously isolated from the potato leaves challenged by P. infestans. The sequence analysis and expression pattern reveal that StPRp27 may be associated with resistance to P. infestans. In present research, transient expression of StPRp27 in Nicotiana benthamiana enhanced resistance to P. infestans isolates 99189 and PY23 indicating its potential contribution to the disease resistance. These findings were also confirmed by over-expression of StPRp27 in potato cv. E-potato 3, which significantly slowed down the development of the disease after inoculation with a mixture of P. infestans races. Further, silencing of StPRp27 homologous genes in N. benthamiana harboring dominant Phytophthora resistance gene Rpi-blb1 or Rpi-blb2 showed no effects on the resistance triggered by these R genes. Our results suggest that StPRp27 contributes to a race-nonspecific resistance against P. infestans by inhibiting the disease development and has a potential use in selection and breeding for durable resistance to late blight.

  13. Methanol extract of mycelia from Phytophthora infestans-induced resistance in potato.

    Science.gov (United States)

    Monjil, Mohammad Shahjahan; Nozawa, Takeshi; Shibata, Yusuke; Takemoto, Daigo; Ojika, Makoto; Kawakita, Kazuhito

    2015-03-01

    Plants recognize certain microbial compounds as elicitors in their active defence mechanisms. It has been shown that a series of defence reactions are induced in potato plant cells after treatment with water-soluble hyphal wall components prepared from Phytophthora infestans. In this study, a methanol extract from mycelia of P. infestans (MEM), which contains lipophilic compounds, was used as another elicitor for the induction of the defence reactions in potato. MEM elicitor induced reactive oxygen species (ROS), especially O2(-) and H2O2 production, and nitric oxide (NO) generation in potato leaves and suspension-cultured cells. Hypersensitive cell death was detected in potato leaves within 6-8 h after MEM elicitor treatment. The accumulation of phytoalexins was detected by MEM elicitor treatment in potato tubers. In potato suspension-cultured cells, several defence-related genes were induced by MEM elicitors, namely Strboh, Sthsr203J, StPVS3, StPR1, and StNR5, which regulate various defence-related functions. Enhanced resistance against P. infestans was found in MEM-treated potato plants. These results suggested that MEM elicitor is recognized by host and enhances defence activities to produce substances inhibitory to pathogens.

  14. Prediction and validation of potential pathogenic microRNAs involved in Phytophthora infestans infection.

    Science.gov (United States)

    Cui, Juanjuan; Luan, Yushi; Wang, Weichen; Zhai, Junmiao

    2014-03-01

    Being one kind of approximately 22nt long small RNA, miRNA has shown its roles in host-pathogen interaction, providing one possible way for pathogen infection. Though Phytophthora infestans is a major pathogen that causes devastating late blight of potato, tomato and so on, so far there have not been any systematic researches on miRNAs and even pathogenic miRNAs in P. infestans. Here, for the first time we comprehensively predicted and identified pathogenic miRNAs that may exist in P. infestans. First, a total of 128 putative miRNAs belonging to 66 miRNA family were identified by bioinformatic approaches. Then, 33 vital pathogenic miRNAs were screened by constructing miRNA-miRNA relationship networks. Finally, four potential pathogenic miRNAs were chosen for detection, two of which are chosen for validation. The expression quantity of pi-miR466 and pi-miR1918 changed dramatically during incubation of tomato leaves, implying that they are potential pathogenic miRNAs.

  15. Metalaxyl Resistance in Phytophthora infestans: Assessing Role of RPA190 Gene and Diversity Within Clonal Lineages.

    Science.gov (United States)

    Matson, Michael E H; Small, Ian M; Fry, William E; Judelson, Howard S

    2015-12-01

    Prior work has shown that the inheritance of resistance to metalaxyl, an oomycete-specific fungicide, is complex and may involve multiple genes. Recent research indicated that a single nucleotide polymorphism (SNP) in the gene encoding RPA190, the largest subunit of RNA polymerase I, confers resistance to metalaxyl (or mefenoxam) in some isolates of the potato late blight pathogen Phytophthora infestans. Using both DNA sequencing and high resolution melt assays for distinguishing RPA190 alleles, we show here that the SNP is absent from certain resistant isolates of P. infestans from North America, Europe, and Mexico. The SNP is present in some members of the US-23 and US-24 clonal lineages, but these tend to be fairly sensitive to the fungicide based on artificial media and field test data. Diversity in the level of sensitivity, RPA190 genotype, and RPA190 copy number was observed in these lineages but were uncorrelated. Controlled laboratory crosses demonstrated that RPA190 did not cosegregate with metalaxyl resistance from a Mexican and British isolate. We conclude that while metalaxyl may be used to control many contemporary strains of P. infestans, an assay based on RPA190 will not be sufficient to diagnose the sensitivity levels of isolates.

  16. Biocontrol of Phytophthora infestans, Fungal Pathogen of Seedling Damping Off Disease in Economic Plant Nursery

    Directory of Open Access Journals (Sweden)

    B. Loliam

    2012-01-01

    Full Text Available This research aims to control Seedling damping off disease in plants by using antagonistic actinomycetes against the causative fungi. Phytophthora infestans was isolated from the infected tomato plant seedling obtained from an economic plant nursery in Amphoe Pak Chong, Nakhon Ratchasima Province, Thailand. The chitinolytic Streptomyces rubrolavendulae S4, isolated from termite mounds at the grove of Amphoe Si-Sawat, Kanchanaburi Province, Thailand, was proven to be the most effective growth inhibition of fungal pathogens tested on potato dextrose agar. Tomato and chili seedlings that colonized with antagonistic S. rubrolavendulae S4 were grown in P. infestans artificial inoculated peat moss. Percents of noninfested seedling in fungal contaminated peat moss were compared to the controls with uninoculated peat moss. In P. infestans contaminated peat moss, the percents of survival of tomato and chili seedling were significantly increased (0.05. It was clearly demonstrated that S. rubrolavendulae S4 can prevent the tomato and chili seedling damping off disease in economic plant nurseries.

  17. The plant pathogen Phytophthora andina emerged via hybridization of an unknown Phytophthora species and the Irish potato famine pathogen, P. infestans.

    Science.gov (United States)

    Goss, Erica M; Cardenas, Martha E; Myers, Kevin; Forbes, Gregory A; Fry, William E; Restrepo, Silvia; Grünwald, Niklaus J

    2011-01-01

    Emerging plant pathogens have largely been a consequence of the movement of pathogens to new geographic regions. Another documented mechanism for the emergence of plant pathogens is hybridization between individuals of different species or subspecies, which may allow rapid evolution and adaptation to new hosts or environments. Hybrid plant pathogens have traditionally been difficult to detect or confirm, but the increasing ease of cloning and sequencing PCR products now makes the identification of species that consistently have genes or alleles with phylogenetically divergent origins relatively straightforward. We investigated the genetic origin of Phytophthora andina, an increasingly common pathogen of Andean crops Solanum betaceum, S. muricatum, S. quitoense, and several wild Solanum spp. It has been hypothesized that P. andina is a hybrid between the potato late blight pathogen P. infestans and another Phytophthora species. We tested this hypothesis by cloning four nuclear loci to obtain haplotypes and using these loci to infer the phylogenetic relationships of P. andina to P. infestans and other related species. Sequencing of cloned PCR products in every case revealed two distinct haplotypes for each locus in P. andina, such that each isolate had one allele derived from a P. infestans parent and a second divergent allele derived from an unknown species that is closely related but distinct from P. infestans, P. mirabilis, and P. ipomoeae. To the best of our knowledge, the unknown parent has not yet been collected. We also observed sequence polymorphism among P. andina isolates at three of the four loci, many of which segregate between previously described P. andina clonal lineages. These results provide strong support that P. andina emerged via hybridization between P. infestans and another unknown Phytophthora species also belonging to Phytophthora clade 1c.

  18. The plant pathogen Phytophthora andina emerged via hybridization of an unknown Phytophthora species and the Irish potato famine pathogen, P. infestans.

    Directory of Open Access Journals (Sweden)

    Erica M Goss

    Full Text Available Emerging plant pathogens have largely been a consequence of the movement of pathogens to new geographic regions. Another documented mechanism for the emergence of plant pathogens is hybridization between individuals of different species or subspecies, which may allow rapid evolution and adaptation to new hosts or environments. Hybrid plant pathogens have traditionally been difficult to detect or confirm, but the increasing ease of cloning and sequencing PCR products now makes the identification of species that consistently have genes or alleles with phylogenetically divergent origins relatively straightforward. We investigated the genetic origin of Phytophthora andina, an increasingly common pathogen of Andean crops Solanum betaceum, S. muricatum, S. quitoense, and several wild Solanum spp. It has been hypothesized that P. andina is a hybrid between the potato late blight pathogen P. infestans and another Phytophthora species. We tested this hypothesis by cloning four nuclear loci to obtain haplotypes and using these loci to infer the phylogenetic relationships of P. andina to P. infestans and other related species. Sequencing of cloned PCR products in every case revealed two distinct haplotypes for each locus in P. andina, such that each isolate had one allele derived from a P. infestans parent and a second divergent allele derived from an unknown species that is closely related but distinct from P. infestans, P. mirabilis, and P. ipomoeae. To the best of our knowledge, the unknown parent has not yet been collected. We also observed sequence polymorphism among P. andina isolates at three of the four loci, many of which segregate between previously described P. andina clonal lineages. These results provide strong support that P. andina emerged via hybridization between P. infestans and another unknown Phytophthora species also belonging to Phytophthora clade 1c.

  19. De novo pyrimidine biosynthesis in the oomycete plant pathogen Phytophthora infestans.

    Science.gov (United States)

    García-Bayona, Leonor; Garavito, Manuel F; Lozano, Gabriel L; Vasquez, Juan J; Myers, Kevin; Fry, William E; Bernal, Adriana; Zimmermann, Barbara H; Restrepo, Silvia

    2014-03-10

    The oomycete Phytophthora infestans, causal agent of the tomato and potato late blight, generates important economic and environmental losses worldwide. As current control strategies are becoming less effective, there is a need for studies on oomycete metabolism to help identify promising and more effective targets for chemical control. The pyrimidine pathways are attractive metabolic targets to combat tumors, virus and parasitic diseases but have not yet been studied in Phytophthora. Pyrimidines are involved in several critical cellular processes and play structural, metabolic and regulatory functions. Here, we used genomic and transcriptomic information to survey the pyrimidine metabolism during the P. infestans life cycle. After assessing the putative gene machinery for pyrimidine salvage and de novo synthesis, we inferred genealogies for each enzymatic domain in the latter pathway, which displayed a mosaic origin. The last two enzymes of the pathway, orotate phosphoribosyltransferase and orotidine-5-monophosphate decarboxylase, are fused in a multi-domain enzyme and are duplicated in some P. infestans strains. Two splice variants of the third gene (dihydroorotase) were identified, one of them encoding a premature stop codon generating a non-functional truncated protein. Relative expression profiles of pyrimidine biosynthesis genes were evaluated by qRT-PCR during infection in Solanum phureja. The third and fifth genes involved in this pathway showed high up-regulation during biotrophic stages and down-regulation during necrotrophy, whereas the uracil phosphoribosyl transferase gene involved in pyrimidine salvage showed the inverse behavior. These findings suggest the importance of de novo pyrimidine biosynthesis during the fast replicative early infection stages and highlight the dynamics of the metabolism associated with the hemibiotrophic life style of pathogen.

  20. Genome-wide prediction and functional validation of promoter motifs regulating gene expression in spore and infection stages of Phytophthora infestans.

    Science.gov (United States)

    Roy, Sourav; Kagda, Meenakshi; Judelson, Howard S

    2013-03-01

    Most eukaryotic pathogens have complex life cycles in which gene expression networks orchestrate the formation of cells specialized for dissemination or host colonization. In the oomycete Phytophthora infestans, the potato late blight pathogen, major shifts in mRNA profiles during developmental transitions were identified using microarrays. We used those data with search algorithms to discover about 100 motifs that are over-represented in promoters of genes up-regulated in hyphae, sporangia, sporangia undergoing zoosporogenesis, swimming zoospores, or germinated cysts forming appressoria (infection structures). Most of the putative stage-specific transcription factor binding sites (TFBSs) thus identified had features typical of TFBSs such as position or orientation bias, palindromy, and conservation in related species. Each of six motifs tested in P. infestans transformants using the GUS reporter gene conferred the expected stage-specific expression pattern, and several were shown to bind nuclear proteins in gel-shift assays. Motifs linked to the appressoria-forming stage, including a functionally validated TFBS, were over-represented in promoters of genes encoding effectors and other pathogenesis-related proteins. To understand how promoter and genome architecture influence expression, we also mapped transcription patterns to the P. infestans genome assembly. Adjacent genes were not typically induced in the same stage, including genes transcribed in opposite directions from small intergenic regions, but co-regulated gene pairs occurred more than expected by random chance. These data help illuminate the processes regulating development and pathogenesis, and will enable future attempts to purify the cognate transcription factors.

  1. Inoculation of Transgenic Resistant Potato by Phytophthora infestans Affects Host Plant Choice of a Generalist Moth.

    Science.gov (United States)

    Abreha, Kibrom B; Alexandersson, Erik; Vossen, Jack H; Anderson, Peter; Andreasson, Erik

    2015-01-01

    Pathogen attack and the plant's response to this attack affect herbivore oviposition preference and larval performance. Introduction of major resistance genes against Phytophthora infestans (Rpi-genes), the cause of the devastating late blight disease, from wild Solanum species into potato changes the plant-pathogen interaction dynamics completely, but little is known about the effects on non-target organisms. Thus, we examined the effect of P. infestans itself and introduction of an Rpi-gene into the crop on host plant preference of the generalist insect herbivore, Spodoptera littoralis (Lepidoptera: Noctuidae). In two choice bioassays, S. littoralis preferred to oviposit on P. infestans-inoculated plants of both the susceptible potato (cv. Desiree) and an isogenic resistant clone (A01-22: cv. Desiree transformed with Rpi-blb1), when compared to uninoculated plants of the same genotype. Both cv. Desiree and clone A01-22 were equally preferred for oviposition by S. littoralis when uninoculated plants were used, while cv. Desiree received more eggs compared to the resistant clone when both were inoculated with the pathogen. No significant difference in larval and pupal weight was found between S. littoralis larvae reared on leaves of the susceptible potato plants inoculated or uninoculated with P. infestans. Thus, the herbivore's host plant preference in this system was not directly associated with larval performance. The results indicate that the Rpi-blb1 based resistance in itself does not influence insect behavior, but that herbivore oviposition preference is affected by a change in the plant-microbe interaction.

  2. Population changes in Phytophthora infestans in Taiwan associated with the appearance of resistance to metalaxyl.

    Science.gov (United States)

    Deahl, Kenneth L; Cooke, Louise R; Black, Lowell L; Wang, Tien Chen; Perez, Frances M; Moravec, Brian C; Quinn, Michele; Jones, Richard W

    2002-09-01

    In recent years, late blight, caused by Phytophthora infestans (Mont) De Bary, has increased in severity in many parts of the world, and this has been associated with migrations which have introduced new, arguably more aggressive, populations of the pathogen. In Taiwan, late blight has been endemic on outdoor tomato crops grown in the highlands since the early 1900s, but recent epidemics have been more damaging. To ascertain the present status of the Taiwanese population of P infestans, 139 isolates of the pathogen collected and maintained by the Asian Vegetable Research and Development Center (AVRDC) were characterized using mating type, metalaxyl sensitivity, allozyme genotype, mitochondrial haplotype and RFLP fingerprinting. Up to 1997, all isolates were found to belong to the old clonal lineage of P infestans (US-1 and variants), but in isolates from 1998 a new genotype appeared, and by 2000 this had apparently completely displaced the old population. This new genotype was an A1 mating type and has the dilocus allozyme genotype 100/100/111, 100/100 for the loci coding for glucose-6-phosphate isomerase and peptidase, respectively. These characters, together with RG57 fingerprinting, indicated that these isolates belonged to the US-11 clonal lineage, a minority (11%) being a previously unreported variant of US-11. Whereas metalaxyl-resistant isolates were not detected in the old population, 96% of the new genotypes proved resistant, with the remainder being intermediate in sensitivity. It may be inferred from this sudden, marked change in the characteristics of the Taiwanese P infestans that a new population of the pathogen was introduced around 1997-98 and that this may well have already been metalaxyl-resistant when it arrived, although a role for in situ selection cannot be excluded.

  3. Inoculation of Transgenic Resistant Potato by Phytophthora infestans Affects Host Plant Choice of a Generalist Moth.

    Directory of Open Access Journals (Sweden)

    Kibrom B Abreha

    Full Text Available Pathogen attack and the plant's response to this attack affect herbivore oviposition preference and larval performance. Introduction of major resistance genes against Phytophthora infestans (Rpi-genes, the cause of the devastating late blight disease, from wild Solanum species into potato changes the plant-pathogen interaction dynamics completely, but little is known about the effects on non-target organisms. Thus, we examined the effect of P. infestans itself and introduction of an Rpi-gene into the crop on host plant preference of the generalist insect herbivore, Spodoptera littoralis (Lepidoptera: Noctuidae. In two choice bioassays, S. littoralis preferred to oviposit on P. infestans-inoculated plants of both the susceptible potato (cv. Desiree and an isogenic resistant clone (A01-22: cv. Desiree transformed with Rpi-blb1, when compared to uninoculated plants of the same genotype. Both cv. Desiree and clone A01-22 were equally preferred for oviposition by S. littoralis when uninoculated plants were used, while cv. Desiree received more eggs compared to the resistant clone when both were inoculated with the pathogen. No significant difference in larval and pupal weight was found between S. littoralis larvae reared on leaves of the susceptible potato plants inoculated or uninoculated with P. infestans. Thus, the herbivore's host plant preference in this system was not directly associated with larval performance. The results indicate that the Rpi-blb1 based resistance in itself does not influence insect behavior, but that herbivore oviposition preference is affected by a change in the plant-microbe interaction.

  4. Potassium phosphite primes defense responses in potato against Phytophthora infestans.

    Science.gov (United States)

    Machinandiarena, Milagros Florencia; Lobato, María Candela; Feldman, Mariana Laura; Daleo, Gustavo Raúl; Andreu, Adriana Balbina

    2012-09-15

    Although phosphite is widely used to protect plants from pathogenic oomycetes on a wide range of horticultural crops, the molecular mechanisms behind phosphite induced resistance are poorly understood. The aim of this work was to assess the effects of potassium phosphite (KPhi) on potato plant defense responses to infection with Phytophtora infestans (Pi). Pathogen development was severely restricted and there was also an important decrease in lesion size in infected KPhi-treated leaves. We demonstrated that KPhi primed hydrogen peroxide and superoxide anion production in potato leaves at 12 h post-inoculation with Pi. Moreover, the KPhi-treated leaves showed an increased and earlier callose deposition as compared with water-treated plants, beginning 48 h after inoculation. In contrast, callose deposition was not detected in water-treated leaves until 72 h after inoculation. In addition, we carried out RNA gel blot analysis of genes implicated in the responses mediated by salicylic (SA) and jasmonic acid (JA). To this end, we examined the temporal expression pattern of StNPR1 and StWRKY1, two transcription factors related to SA pathway, and StPR1 and StIPII, marker genes related to SA and JA pathways, respectively. The expression of StNPR1 and StWRKY1 was enhanced in response to KPhi treatment. In contrast, StIPII was down regulated in both KPhi- and water-treated leaves, until 48 h after infection with Pi, suggesting that the regulation of this gene could be independent of the KPhi treatment. Our results indicate that KPhi primes the plant for an earlier and more intense response to infection and that SA would mediate this response.

  5. Population Structure of the Late Blight Pathogen Phytophthora infestans in a Potato Germplasm Nursery in Two Consecutive Years.

    Science.gov (United States)

    Tian, Yuee; Yin, Junliang; Sun, Jieping; Ma, Hongmei; Ma, Yunfang; Quan, Junli; Shan, Weixing

    2015-06-01

    As the causal agent of late blight on potato, Phytophthora infestans is one of the most destructive plant pathogens worldwide and widely known as the Irish potato famine pathogen. Understanding the genetic structure of P. infestans populations is important both for breeding and deployment of resistant varieties and for development of disease control strategies. Here, we investigate the population genetic structure of P. infestans in a potato germplasm nursery in northwestern China. In total, 279 isolates were recovered from 63 potato varieties or lines in 2010 and 2011, and were genotyped by mitochondrial DNA haplotypes and a set of nine simple-sequence repeat markers. Selected isolates were further examined for virulence on a set of differential lines containing each resistance (R) gene (R1 to R11). The overall P. infestans population was characterized as having a low level of genetic diversity and resistance to metalaxyl, and containing a high percentage of individuals that virulent to all 11 R genes. Both A1 and A2 mating types as well as self-fertile P. infestans isolates were present but there was no evidence of sexual reproduction. The low level of genetic differentiation in P. infestans populations is probably due to the action of relatively high levels of migration as supported by analysis of molecular variance (P infestans population structure in the germplasm nursery. Therefore, it is important to ensure the production of pathogen-free potato seed tubers to aid sustainable production of potato in northwestern China.

  6. Alteration of secondary metabolites' profiles in potato leaves in response to weakly and highly aggressive isolates of Phytophthora infestans.

    Science.gov (United States)

    Henriquez, Maria A; Adam, Lorne R; Daayf, Fouad

    2012-08-01

    Phytophthora infestans is the cause of late blight, a devastating disease in potato and tomato. Many of the mechanisms underlying P. infestans pathogenesis and defense responses in potato are still unclear. We investigated the effects of P. infestans on the changes in the accumulation of secondary metabolites in potato cultivars using whole plants. Four preformed flavonoids and one terpenoid compound produced in potato tissues were differentially affected by the P. infestans inoculation. In Russet Burbank, the accumulation of catechin and rutin was suppressed by both P. infestans isolates US-11 and US-8, while the flavanone P3 was associated with susceptibility to this pathogen. On the other hand, catechin, flavonol-glycoside P2, and an unidentified terpenoid (T1), may be involved in the defense of cultivar Defender to both tested P. infestans isolates, providing new evidence that different preformed flavonoids and terpenoids in potato may play important roles in its defense or susceptibility to P. infestans. These results add to the pool of data showing the involvement of other phenolics and terpenes in potato resistance to microbial pathogens.

  7. Comparisons of Ribosomal Protein Gene Promoters Indicate Superiority of Heterologous Regulatory Sequences for Expressing Transgenes in Phytophthora infestans.

    Science.gov (United States)

    Poidevin, Laetitia; Andreeva, Kalina; Khachatoorian, Careen; Judelson, Howard S

    2015-01-01

    Molecular genetics approaches in Phytophthora research can be hampered by the limited number of known constitutive promoters for expressing transgenes and the instability of transgene activity. We have therefore characterized genes encoding the cytoplasmic ribosomal proteins of Phytophthora and studied their suitability for expressing transgenes in P. infestans. Phytophthora spp. encode a standard complement of 79 cytoplasmic ribosomal proteins. Several genes are duplicated, and two appear to be pseudogenes. Half of the genes are expressed at similar levels during all stages of asexual development, and we discovered that the majority share a novel promoter motif named the PhRiboBox. This sequence is enriched in genes associated with transcription, translation, and DNA replication, including tRNA and rRNA biogenesis. Promoters from the three P. infestans genes encoding ribosomal proteins S9, L10, and L23 and their orthologs from P. capsici were tested for their ability to drive transgenes in stable transformants of P. infestans. Five of the six promoters yielded strong expression of a GUS reporter, but the stability of expression was higher using the P. capsici promoters. With the RPS9 and RPL10 promoters of P. infestans, about half of transformants stopped making GUS over two years of culture, while their P. capsici orthologs conferred stable expression. Since cross-talk between native and transgene loci may trigger gene silencing, we encourage the use of heterologous promoters in transformation studies.

  8. The Arabidopsis lectin receptor kinase LecRK-I.9 enhances resistance to Phytophthora infestans in Solanaceous plants

    NARCIS (Netherlands)

    Bouwmeester, K.; Han, M.; Blanco-Portales, R.; Song, W.; Weide, R.; Guo, L.Y.; Vossen, van der E.A.G.; Govers, F.

    2014-01-01

    Phytophthora species are notorious plant pathogens which cause a variety of devastating crop diseases. Phytophthora pathogens secrete a plethora of effector proteins, several of which are known to interact with receptors in the host cell thereby either activating or suppressing defense responses. Un

  9. Detection of the virulent form of AVR3a from Phytophthora infestans following artificial evolution of potato resistance gene R3a.

    Directory of Open Access Journals (Sweden)

    Sean Chapman

    Full Text Available Engineering resistance genes to gain effector recognition is emerging as an important step in attaining broad, durable resistance. We engineered potato resistance gene R3a to gain recognition of the virulent AVR3aEM effector form of Phytophthora infestans. Random mutagenesis, gene shuffling and site-directed mutagenesis of R3a were conducted to produce R3a* variants with gain of recognition towards AVR3aEM. Programmed cell death following gain of recognition was enhanced in iterative rounds of artificial evolution and neared levels observed for recognition of AVR3aKI by R3a. We demonstrated that R3a*-mediated recognition responses, like for R3a, are dependent on SGT1 and HSP90. In addition, this gain of response is associated with re-localisation of R3a* variants from the cytoplasm to late endosomes when co-expressed with either AVR3aKI or AVR3aEM a mechanism that was previously only seen for R3a upon co-infiltration with AVR3aKI. Similarly, AVR3aEM specifically re-localised to the same vesicles upon recognition by R3a* variants, but not with R3a. R3a and R3a* provide resistance to P. infestans isolates expressing AVR3aKI but not those homozygous for AVR3aEM.

  10. Detection of the virulent form of AVR3a from Phytophthora infestans following artificial evolution of potato resistance gene R3a.

    Science.gov (United States)

    Chapman, Sean; Stevens, Laura J; Boevink, Petra C; Engelhardt, Stefan; Alexander, Colin J; Harrower, Brian; Champouret, Nicolas; McGeachy, Kara; Van Weymers, Pauline S M; Chen, Xinwei; Birch, Paul R J; Hein, Ingo

    2014-01-01

    Engineering resistance genes to gain effector recognition is emerging as an important step in attaining broad, durable resistance. We engineered potato resistance gene R3a to gain recognition of the virulent AVR3aEM effector form of Phytophthora infestans. Random mutagenesis, gene shuffling and site-directed mutagenesis of R3a were conducted to produce R3a* variants with gain of recognition towards AVR3aEM. Programmed cell death following gain of recognition was enhanced in iterative rounds of artificial evolution and neared levels observed for recognition of AVR3aKI by R3a. We demonstrated that R3a*-mediated recognition responses, like for R3a, are dependent on SGT1 and HSP90. In addition, this gain of response is associated with re-localisation of R3a* variants from the cytoplasm to late endosomes when co-expressed with either AVR3aKI or AVR3aEM a mechanism that was previously only seen for R3a upon co-infiltration with AVR3aKI. Similarly, AVR3aEM specifically re-localised to the same vesicles upon recognition by R3a* variants, but not with R3a. R3a and R3a* provide resistance to P. infestans isolates expressing AVR3aKI but not those homozygous for AVR3aEM.

  11. Tomato I2 Immune Receptor Can Be Engineered to Confer Partial Resistance to the Oomycete Phytophthora infestans in Addition to the Fungus Fusarium oxysporum.

    Science.gov (United States)

    Giannakopoulou, Artemis; Steele, John F C; Segretin, Maria Eugenia; Bozkurt, Tolga O; Zhou, Ji; Robatzek, Silke; Banfield, Mark J; Pais, Marina; Kamoun, Sophien

    2015-12-01

    Plants and animals rely on immune receptors, known as nucleotide-binding domain and leucine-rich repeat (NLR)-containing proteins, to defend against invading pathogens and activate immune responses. How NLR receptors respond to pathogens is inadequately understood. We previously reported single-residue mutations that expand the response of the potato immune receptor R3a to AVR3a(EM), a stealthy effector from the late blight oomycete pathogen Phytophthora infestans. I2, another NLR that mediates resistance to the will-causing fungus Fusarium oxysporum f. sp. lycopersici, is the tomato ortholog of R3a. We transferred previously identified R3a mutations to I2 to assess the degree to which the resulting I2 mutants have an altered response. We discovered that wild-type I2 protein responds weakly to AVR3a. One mutant in the N-terminal coiled-coil domain, I2(I141N), appeared sensitized and displayed markedly increased response to AVR3a. Remarkably, I2(I141N) conferred partial resistance to P. infestans. Further, I2(I141N) has an expanded response spectrum to F. oxysporum f. sp. lycopersici effectors compared with the wild-type I2 protein. Our results suggest that synthetic immune receptors can be engineered to confer resistance to phylogenetically divergent pathogens and indicate that knowledge gathered for one NLR could be exploited to improve NLR from other plant species.

  12. Phenazine-1-Carboxylic Acid Production by Pseudomonas fluorescens LBUM636 Alters Phytophthora infestans Growth and Late Blight Development.

    Science.gov (United States)

    Morrison, Christopher K; Arseneault, Tanya; Novinscak, Amy; Filion, Martin

    2017-03-01

    Phytophthora infestans causes late blight of potato, one of the most devastating diseases affecting potato production. Alternative approaches for controlling late blight are being increasingly sought due to increasing environmental concerns over the use of chemical pesticides and the increasing resistance of P. infestans to fungicides. Our research group has isolated a new strain of Pseudomonas fluorescens (LBUM636) of biocontrol interest producing the antibiotic phenazine-1-carboxylic acid (PCA). Wild-type LBUM636 was shown to significantly inhibit the growth of Phytophthora infestans in in vitro confrontational assays whereas its isogenic mutant (phzC-; not producing PCA) only slightly altered the pathogen's growth. Wild-type LBUM636 but not the phzC- mutant also completely repressed disease symptom development on tubers. A pot experiment revealed that wild-type LBUM636 can significantly reduce P. infestans populations in the rhizosphere and in the roots of potato plants, as well as reduce in planta disease symptoms due to PCA production. The expression of eight common plant defense-related genes (ChtA, PR-1b, PR-2, PR-5, LOX, PIN2, PAL-2, and ERF3) was quantified in tubers, roots, and leaves by reverse-transcription quantitative polymerase chain reaction and revealed that the biocontrol observed was not associated with the induction of a plant defense response by LBUM636. Instead, a direct interaction between P. infestans and LBUM636 is required and PCA production appears to be a key factor for LBUM636's biocontrol ability.

  13. In vitro translocation experiments with RxLR-reporter fusion proteins of Avr1b from Phytophthora sojae and AVR3a from Phytophthora infestans fail to demonstrate specific autonomous uptake in plant and animal cells.

    Science.gov (United States)

    Wawra, Stephan; Djamei, Armin; Albert, Isabell; Nürnberger, Thorsten; Kahmann, Regine; van West, Pieter

    2013-05-01

    Plant-pathogenic oomycetes have a large set of secreted effectors that can be translocated into their host cells during infection. One group of these effectors are the RxLR effectors for which it has been shown, in a few cases, that the RxLR motif is important for their translocation. It has been suggested that the RxLR-leader sequences alone are enough to translocate the respective effectors into eukaryotic cells through binding to surface-exposed phosphoinositol-3-phosphate. These conclusions were primary based on translocation experiments conducted with recombinant fusion proteins whereby the RxLR leader of RxLR effectors (i.e., Avr1b from Phytophthora sojae) were fused to the green fluorescent protein reporter-protein. However, we failed to observe specific cellular uptake for a comparable fusion protein where the RxLR leader of the P. infestans AVR3a was fused to monomeric red fluorescent protein. Therefore, we reexamined the ability of the reported P. sojae AVR1b RxLR leader to enter eukaryotic cells. Different relevant experiments were performed in three independent laboratories, using fluorescent reporter fusion constructs of AVR3a and Avr1b proteins in a side-by-side comparative study on plant tissue and human and animal cells. We report that we were unable to obtain conclusive evidence for specific RxLR-mediated translocation.

  14. Genetic analysis of Phytophthora infestans populations in the Nordic European countries reveals high genetic variability

    DEFF Research Database (Denmark)

    Brurberg, May Bente; Elameen, Abdelhameed; Le, Ving Hong

    2011-01-01

    Late blight, caused by the oomycete Phytophthora infestans, is the most important disease of potato (Solanum tuberosum). The pathogen is highly adaptable and to get an overview of the genetic variation in the Nordic countries, Denmark, Finland, Norway and Sweden we have analyzed 200 isolates from...... different fields using nine simple-sequence repeat (SSR) markers. Forty-nine alleles were detected among the nine SSR loci and isolates from all four Nordic countries shared the most common alleles across the loci. In total 169 multilocus genotypes (based on seven loci) were identified among 191 isolates....... The genotypic diversities, quantified by a normalized Shannon’s diversity index (Hs), were 0.95 for the four Nordic countries. The low FST value of 0.04 indicates that the majority of variation is found within the four Nordic countries. The large number of genotypes and the frequency distribution of mating...

  15. Expresión diferencial durante la interacción Solanum tuberosum - Phytophthora infestans

    Directory of Open Access Journals (Sweden)

    Zulma Isabel Monsalve-Fonnegra

    2013-02-01

    Full Text Available Normal 0 21 false false false ES-CO X-NONE X-NONE MicrosoftInternetExplorer4 Título en ingles: Differential expression during Solanum tuberosum- Phytophthora infestans interactionResumen: La papa (Solanum tuberosum L. es el cuarto cultivo más importante a nivel mundial y es el producto agrícola con mayor demanda de fungicidas, insecticidas y fertilizantes químicos. Las pérdidas mundiales ocasionadas por Phytophthora infestans (Mont. de Bary en este cultivo, ascienden a 6,7 billones de dólares al año y su control químico genera un aumento en los costos, perjudica la salud humana y el ambiente. Todo esto justifica la búsqueda constante de mecanismos alternativos para el control de la enfermedad, entre ellos la obtención de variedades resistentes mediante cisgenesis usando genotipos silvestres. Como un aporte en este sentido, y dada la falta de conocimiento de lo que controla y constituye la diferencia entre una respuesta compatible e incompatible, en el presente estudio se compararon los perfiles de expresión génica obtenidos mediante Despliegue Diferencial de variedades resistentes y susceptibles durante su interacción con P. infestans. Los resultados evidenciaron diferencias en la expresión génica, tanto a distintos tiempos post-inoculación como en el tipo de cambio de expresión, incluyendo la presencia y ausencia de bandas diferenciales y el aumento o disminución en su intensidad. Al analizar las secuencias de fragmentos diferencialmente expresados, se encontró que algunos fragmentos sobre-expresados en las variedades susceptibles, tenían homología con secuencias que codifican para una serina-acetiltranferasa y para la subunidad β de la RNA polimerasa. Por su parte, fragmentos sobre-expresados en la variedad resistente, tenían homología con una secuencia codificante para un dominio transmembranal. Palabras claves: pastusa suprema;  diacol-capiro; parda pastusa; despliegue diferencial Abstract: Potato (Solanum tuberosum

  16. Research Advance of Interaction Mechanism between Phytophthora infestans and Potato%致病疫霉(Phytophthora infestans)与马铃薯间相互作用机理的研究进展

    Institute of Scientific and Technical Information of China (English)

    徐安传; 罗文富

    2001-01-01

    根据近年来致病疫霉(Phytophthora infestans)与马铃薯间相互作用的研究成果,阐述在致病疫霉(P.infestans)与马铃薯间相互作用的过程中,马铃薯小种专化性抗性基因与致病疫霉的无毒性基因间的相互关系,分析在此互作时所产生的二十碳四烯酸(AA)、二十碳戊烯酸(EPA)、葡聚糖、茉莉酸(JA)以及各种病程相关蛋白(PRprotein)等物质的调控作用,从而进一步论述致病疫霉(P.infestans)与马铃薯间相互作用的机理.

  17. Comparative analysis of sterol acquisition in the oomycetes Saprolegnia parasitica and Phytophthora infestans

    Science.gov (United States)

    Dahlin, Paul; Srivastava, Vaibhav; Ekengren, Sophia; McKee, Lauren S.; Bulone, Vincent

    2017-01-01

    The oomycete class includes pathogens of animals and plants which are responsible for some of the most significant global losses in agriculture and aquaculture. There is a need to replace traditional chemical means of controlling oomycete growth with more targeted approaches, and the inhibition of sterol synthesis is one promising area. To better direct these efforts, we have studied sterol acquisition in two model organisms: the sterol-autotrophic Saprolegnia parasitica, and the sterol-heterotrophic Phytophthora infestans. We first present a comprehensive reconstruction of a likely sterol synthesis pathway for S. parasitica, causative agent of the disease saprolegniasis in fish. This pathway shows multiple potential routes of sterol synthesis, and draws on several avenues of new evidence: bioinformatic mining for genes with sterol-related functions, expression analysis of these genes, and analysis of the sterol profiles in mycelium grown in different media. Additionally, we explore the extent to which P. infestans, which causes the late blight in potato, can modify exogenously provided sterols. We consider whether the two very different approaches to sterol acquisition taken by these pathogens represent any specific survival advantages or potential drug targets. PMID:28152045

  18. The rise and fall of the Phytophthora infestans lineage that triggered the Irish potato famine.

    Science.gov (United States)

    Yoshida, Kentaro; Schuenemann, Verena J; Cano, Liliana M; Pais, Marina; Mishra, Bagdevi; Sharma, Rahul; Lanz, Chirsta; Martin, Frank N; Kamoun, Sophien; Krause, Johannes; Thines, Marco; Weigel, Detlef; Burbano, Hernán A

    2013-05-28

    Phytophthora infestans, the cause of potato late blight, is infamous for having triggered the Irish Great Famine in the 1840s. Until the late 1970s, P. infestans diversity outside of its Mexican center of origin was low, and one scenario held that a single strain, US-1, had dominated the global population for 150 years; this was later challenged based on DNA analysis of historical herbarium specimens. We have compared the genomes of 11 herbarium and 15 modern strains. We conclude that the 19th century epidemic was caused by a unique genotype, HERB-1, that persisted for over 50 years. HERB-1 is distinct from all examined modern strains, but it is a close relative of US-1, which replaced it outside of Mexico in the 20th century. We propose that HERB-1 and US-1 emerged from a metapopulation that was established in the early 1800s outside of the species' center of diversity. DOI:http://dx.doi.org/10.7554/eLife.00731.001.

  19. Growth media affect the volatilome and antimicrobial activity against Phytophthora infestans in four Lysobacter type strains.

    Science.gov (United States)

    Lazazzara, Valentina; Perazzolli, Michele; Pertot, Ilaria; Biasioli, Franco; Puopolo, Gerardo; Cappellin, Luca

    2017-08-01

    Bacterial volatile organic compounds (VOCs) play important ecological roles in soil microbial interactions. Lysobacter spp. are key determinants of soil suppressiveness against phytopathogens and the production of non-volatile antimicrobial metabolites has been extensively characterised. However, the chemical composition and antagonistic properties of the Lysobacter volatilome have been poorly investigated. In this work, VOC emission profiles of four Lysobacter type strains grown on a sugar-rich and a protein-rich medium were analysed using solid-phase microextraction gas chromatography-mass spectrometry and proton transfer reaction-time of flight-mass spectrometry. Lysobacter antibioticus, L. capsici, L. enzymogenes and L. gummosus type strains were recognised according to their volatilome assessed using both headspace mass spectrometry methods Moreover, the chemical profiles and functional properties of the Lysobacter volatilome differed according to the growth medium, and a protein-rich substrate maximised the toxic effect of the four Lysobacter type strains against Phytophthora infestans. Antagonistic (pyrazines, pyrrole and decanal) and non-antagonistic (delta-hexalactone and ethanol) VOCs against Ph. infestans or putative plant growth stimulator compounds (acetoin and indole) were mainly emitted by Lysobacter type strains grown on protein- and sugar-rich media respectively. Thus nutrient availability under soil conditions could affect the aggressiveness of Lysobacter spp. and possibly optimise interactions of these bacterial species with the other soil inhabitants. Copyright © 2017 Elsevier GmbH. All rights reserved.

  20. Population Structure of Phytophthora infestans in the Toluca Valley Region of Central Mexico.

    Science.gov (United States)

    Grünwald, N J; Flier, W G; Sturbaum, A K; Garay-Serrano, E; van den Bosch, T B; Smart, C D; Matuszak, J M; Lozoya-Saldaña, H; Turkensteen, L J; Fry, W E

    2001-09-01

    ABSTRACT We tested the hypothesis that the population of Phytophthora infestans in the Toluca valley region is genetically differentiated according to habitat. Isolates were sampled in three habitats from (i) wild Solanum spp. (WILD), (ii) land-race varieties in low-input production systems (RURAL), and (iii) modern cultivars in high-input agriculture (VALLEY). Isolates were sampled in 1988-89 (n= 179) and in 1997-98 (n= 389). In both sampling periods, the greatest genetic diversity was observed in RURAL and VALLEY habitats. Based on the Glucose-6-phosphate isomerase and Peptidase allozymes, the subpopulations from the three habitats were significantly differentiated in both sampling periods. In contrast to allozyme data for 1997-98, no differences were found among the three subpopulations for sensitivity to metalaxyl. Two groups of isolates identical for allozyme and mating type were further investigated by restriction fragment length polymorphism fingerprinting; 65% of one group and 85% of another group were demonstrated to be unique. The genetic diversity data and the chronology of disease occurrence during the season are consistent with the hypothesis that populations of P. infestans on wild Solanum populations are derived from populations on cultivated potatoes in the central highlands of Mexico near Toluca.

  1. The rise and fall of the Phytophthora infestans lineage that triggered the Irish potato famine

    Science.gov (United States)

    Yoshida, Kentaro; Schuenemann, Verena J; Cano, Liliana M; Pais, Marina; Mishra, Bagdevi; Sharma, Rahul; Lanz, Chirsta; Martin, Frank N; Kamoun, Sophien; Krause, Johannes; Thines, Marco; Weigel, Detlef; Burbano, Hernán A

    2013-01-01

    Phytophthora infestans, the cause of potato late blight, is infamous for having triggered the Irish Great Famine in the 1840s. Until the late 1970s, P. infestans diversity outside of its Mexican center of origin was low, and one scenario held that a single strain, US-1, had dominated the global population for 150 years; this was later challenged based on DNA analysis of historical herbarium specimens. We have compared the genomes of 11 herbarium and 15 modern strains. We conclude that the 19th century epidemic was caused by a unique genotype, HERB-1, that persisted for over 50 years. HERB-1 is distinct from all examined modern strains, but it is a close relative of US-1, which replaced it outside of Mexico in the 20th century. We propose that HERB-1 and US-1 emerged from a metapopulation that was established in the early 1800s outside of the species' center of diversity. DOI: http://dx.doi.org/10.7554/eLife.00731.001 PMID:23741619

  2. Historic Late Blight Outbreaks Caused by a Widespread Dominant Lineage of Phytophthora infestans (Mont.) de Bary

    Science.gov (United States)

    Martin, Michael D.

    2016-01-01

    Phytophthora infestans (Mont.) de Bary, the causal agent of potato late blight, was responsible for the Irish potato famine of the 1840s. Initial disease outbreaks occurred in the US in 1843, two years prior to European outbreaks. We examined the evolutionary relationships and source of the 19th-century outbreaks using herbarium specimens of P. infestans from historic (1846–1970) and more recent isolates (1992–2014) of the pathogen. The same unique SSR multilocus genotype, named here as FAM-1, caused widespread outbreaks in both US and Europe. The FAM-1 lineage shared allelic diversity and grouped with the oldest specimens collected in Colombia and Central America. The FAM-1 lineage of P. infestans formed a genetic group that was distinct from more recent aggressive lineages found in the US. The US-1 lineage formed a second, mid-20th century group. Recent modern US lineages and the oldest Mexican lineages formed a genetic group with recent Mexican lineages, suggesting a Mexican origin of recent US lineages. A survey of mitochondrial haplotypes in a larger set of global herbarium specimens documented the more frequent occurrence of the HERB-1 (type Ia) mitochondrial haplotype in archival collections from 1866–75 and 1906–1915 and the rise of the Ib mitochondrial lineage (US-1) between 1946–1955. The FAM-1 SSR lineage survived for almost 100 years in the US, was geographically widespread, and was displaced first in the mid-20th century by the US-1 lineage and then by distinct new aggressive lineages that migrated from Mexico. PMID:28030580

  3. An ephemeral sexual population of Phytophthora infestans in the Northeastern United States and Canada.

    Science.gov (United States)

    Danies, Giovanna; Myers, Kevin; Mideros, María F; Restrepo, Silvia; Martin, Frank N; Cooke, David E L; Smart, Christine D; Ristaino, Jean B; Seaman, Abby J; Gugino, Beth K; Grünwald, Niklaus J; Fry, William E

    2014-01-01

    Phytophthora infestans, the causal agent of late blight disease, has been reported in North America since the mid-nineteenth century. In the United States the lack of or very limited sexual reproduction has resulted in largely clonal populations of P. infestans. In 2010 and 2011, but not in 2012 or 2013, 20 rare and diverse genotypes of P. infestans were detected in a region that centered around central New York State. The ratio of A1 to A2 mating types among these genotypes was close to the 50∶50 ratio expected for sexual recombination. These genotypes were diverse at the glucose-6-phosphate isomerase locus, differed in their microsatellite profiles, showed different banding patterns in a restriction fragment length polymorphism assay using a moderately repetitive and highly polymorphic probe (RG57), were polymorphic for four different nuclear genes and differed in their sensitivity to the systemic fungicide mefenoxam. The null hypothesis of linkage equilibrium was not rejected, which suggests the population could be sexual. These new genotypes were monomorphic in their mitochondrial haplotype that was the same as US-22. Through parentage exclusion testing using microsatellite data and sequences of four nuclear genes, recent dominant lineages US-8, US-11, US-23, and US-24 were excluded as possible parents for these genotypes. Further analyses indicated that US-22 could not be eliminated as a possible parent for 14 of the 20 genotypes. We conclude that US-22 could be a parent of some, but not all, of the new genotypes found in 2010 and 2011. There were at least two other parents for this population and the genotypic characteristics of the other parents were identified.

  4. Species tree estimation for the late blight pathogen, Phytophthora infestans, and close relatives.

    Directory of Open Access Journals (Sweden)

    Jaime E Blair

    Full Text Available To better understand the evolutionary history of a group of organisms, an accurate estimate of the species phylogeny must be known. Traditionally, gene trees have served as a proxy for the species tree, although it was acknowledged early on that these trees represented different evolutionary processes. Discordances among gene trees and between the gene trees and the species tree are also expected in closely related species that have rapidly diverged, due to processes such as the incomplete sorting of ancestral polymorphisms. Recently, methods have been developed for the explicit estimation of species trees, using information from multilocus gene trees while accommodating heterogeneity among them. Here we have used three distinct approaches to estimate the species tree for five Phytophthora pathogens, including P. infestans, the causal agent of late blight disease in potato and tomato. Our concatenation-based "supergene" approach was unable to resolve relationships even with data from both the nuclear and mitochondrial genomes, and from multiple isolates per species. Our multispecies coalescent approach using both Bayesian and maximum likelihood methods was able to estimate a moderately supported species tree showing a close relationship among P. infestans, P. andina, and P. ipomoeae. The topology of the species tree was also identical to the dominant phylogenetic history estimated in our third approach, Bayesian concordance analysis. Our results support previous suggestions that P. andina is a hybrid species, with P. infestans representing one parental lineage. The other parental lineage is not known, but represents an independent evolutionary lineage more closely related to P. ipomoeae. While all five species likely originated in the New World, further study is needed to determine when and under what conditions this hybridization event may have occurred.

  5. Interspecific somatic hybrids Solanum villosum (+) S. tuberosum, resistant to Phytophthora infestans.

    Science.gov (United States)

    Tarwacka, Justyna; Polkowska-Kowalczyk, Lidia; Kolano, Bożena; Śliwka, Jadwiga; Wielgat, Bernard

    2013-11-15

    The interspecific somatic hybrids 4x S. villosum (+) 2x S. tuberosum clone DG 81-68 (VT hybrids) were obtained and characterized molecularly and cytogenetically. The morphology of fusion-derived plants was intermediate in relation to the parental species. The expected ploidy level of the regenerants was 6x for the VT hybrids, but the real ploidy of the hybrids varied, with some of them being euploids, and others - aneuploids. The hybridity of the regenerants was verified by random amplified polymorphic DNA (RAPD) analysis. Despite the variation in ploidy, the RAPD patterns of the hybrids were mostly uniform, suggesting similarity of the genotypes of the VT clones. Genomic in situ hybridization (GISH) analysis discriminated between the chromosomes of both parental genomes in VT somatic hybrids and also confirmed their hybridity. The resistance of VT somatic hybrids to Phytophthora infestans was evaluated and all of the hybrids proved to be highly resistant. In search of the mechanisms involved in resistance of the Solanum species to P. infestans, the biochemical reactions occurring early after elicitor treatment were studied. The production of reactive oxygen species (ROS), as one of the earliest reactions induced by pathogens or their elicitors, was examined in the resistant wild species S. villosum, susceptible S. tuberosum clone DG 81-68 and in the VT hybrid, resistant to P. infestans. After treatment of the leaves with elicitor, the relative increase in ROS production was higher in leaves of the susceptible potato clone than in the resistant plants of S. villosum and the somatic hybrid.

  6. Species Tree Estimation for the Late Blight Pathogen, Phytophthora infestans, and Close Relatives

    Science.gov (United States)

    Blair, Jaime E.; Coffey, Michael D.; Martin, Frank N.

    2012-01-01

    To better understand the evolutionary history of a group of organisms, an accurate estimate of the species phylogeny must be known. Traditionally, gene trees have served as a proxy for the species tree, although it was acknowledged early on that these trees represented different evolutionary processes. Discordances among gene trees and between the gene trees and the species tree are also expected in closely related species that have rapidly diverged, due to processes such as the incomplete sorting of ancestral polymorphisms. Recently, methods have been developed for the explicit estimation of species trees, using information from multilocus gene trees while accommodating heterogeneity among them. Here we have used three distinct approaches to estimate the species tree for five Phytophthora pathogens, including P. infestans, the causal agent of late blight disease in potato and tomato. Our concatenation-based “supergene” approach was unable to resolve relationships even with data from both the nuclear and mitochondrial genomes, and from multiple isolates per species. Our multispecies coalescent approach using both Bayesian and maximum likelihood methods was able to estimate a moderately supported species tree showing a close relationship among P. infestans, P. andina, and P. ipomoeae. The topology of the species tree was also identical to the dominant phylogenetic history estimated in our third approach, Bayesian concordance analysis. Our results support previous suggestions that P. andina is a hybrid species, with P. infestans representing one parental lineage. The other parental lineage is not known, but represents an independent evolutionary lineage more closely related to P. ipomoeae. While all five species likely originated in the New World, further study is needed to determine when and under what conditions this hybridization event may have occurred. PMID:22615869

  7. An ephemeral sexual population of Phytophthora infestans in the Northeastern United States and Canada.

    Directory of Open Access Journals (Sweden)

    Giovanna Danies

    Full Text Available Phytophthora infestans, the causal agent of late blight disease, has been reported in North America since the mid-nineteenth century. In the United States the lack of or very limited sexual reproduction has resulted in largely clonal populations of P. infestans. In 2010 and 2011, but not in 2012 or 2013, 20 rare and diverse genotypes of P. infestans were detected in a region that centered around central New York State. The ratio of A1 to A2 mating types among these genotypes was close to the 50∶50 ratio expected for sexual recombination. These genotypes were diverse at the glucose-6-phosphate isomerase locus, differed in their microsatellite profiles, showed different banding patterns in a restriction fragment length polymorphism assay using a moderately repetitive and highly polymorphic probe (RG57, were polymorphic for four different nuclear genes and differed in their sensitivity to the systemic fungicide mefenoxam. The null hypothesis of linkage equilibrium was not rejected, which suggests the population could be sexual. These new genotypes were monomorphic in their mitochondrial haplotype that was the same as US-22. Through parentage exclusion testing using microsatellite data and sequences of four nuclear genes, recent dominant lineages US-8, US-11, US-23, and US-24 were excluded as possible parents for these genotypes. Further analyses indicated that US-22 could not be eliminated as a possible parent for 14 of the 20 genotypes. We conclude that US-22 could be a parent of some, but not all, of the new genotypes found in 2010 and 2011. There were at least two other parents for this population and the genotypic characteristics of the other parents were identified.

  8. Development of alternative strategies for the control of the important phytopathogens Phytophthora infestans (Mont.) and Erwinia amylovora (Burrill)

    OpenAIRE

    2007-01-01

    Within the framework of two projects, financed by DBU (Deutsche Bundesstiftung Umwelt) and ProInno ("Förderung der Erhöhung der Innovationskompetenz mittelständischer Unternehmen"), respectively, in co-operation with an industrial partner, alternative phytosanitary compounds from natural sources have been screened. High throughput screening systems were developed and used for testing of large numbers of extracts of Actinomycetes in 96-well multiplates against Phytophthora infestans and Erwini...

  9. Persistence of the mitochondrial lineage responsible for the Irish potato famine in extant new world phytophthora infestans.

    Science.gov (United States)

    Martin, Michael D; Ho, Simon Y W; Wales, Nathan; Ristaino, Jean B; Gilbert, M Thomas P

    2014-06-01

    The plant pathogen Phytophthora infestans emerged in Europe in 1845, triggering the Irish potato famine and massive European potato crop losses that continued until effective fungicides were widely employed in the 20th century. Today the pathogen is ubiquitous, with more aggressive and virulent strains surfacing in recent decades. Recently, complete P. infestans mitogenome sequences from 19th-century herbarium specimens were shown to belong to a unique lineage (HERB-1) predicted to be rare or extinct in modern times. We report 44 additional P. infestans mitogenomes: four from 19th-century Europe, three from 1950s UK, and 37 from modern populations across the New World. We use phylogenetic analyses to identify the HERB-1 lineage in modern populations from both Mexico and South America, and to demonstrate distinct mitochondrial haplotypes were present in 19th-century Europe, with this lineage initially diversifying 75 years before the first reports of potato late blight.

  10. Mitochondrial DNA polymorphisms in Phytophthora infestans: new haplotypes are identified and re-defined by PCR.

    Science.gov (United States)

    Yang, Zhi-Hui; Qi, Ming-Xing; Qin, Yu-Xuan; Zhu, Jie-Hua; Gui, Xiu-Mei; Tao, Bu; Xu, Xiao-Hu; Zhang, Fu-Guang

    2013-11-01

    Polymorphisms of mitochondrial DNA (mt-DNA) are particularly useful for monitoring specific pathogen populations like Phytophthora infestans. Basically type I and II of P. infestans mt-DNA were categorized by means of polymorphism lengths caused by an ~2 kb insertion, which can be detected via restriction enzyme digestion. In addition genome sequencing of haplotype Ib has been used as a simple Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method to indirectly identify type I and II alterations through EcoR I restriction enzyme DNA fragment patterns of the genomic P4 area. However, with the common method, wrong mt-DNA typing occurs due to an EcoR I recognition site mutation in the P4 genomic area. Genome sequencing of the four haplotypes (Ia, Ib, IIa, and IIb) allowed us to thoroughly examine mt-DNA polymorphisms and we indentified two hypervariable regions (HVRs) named HVRi and HVRii. The HVRi length polymorphism caused by a 2 kb insertion/deletion was utilized to identify mt-DNA types I and II, while another length polymorphism in the HVRii region is caused by a variable number of tandem repeats (n = 1, 2, or 3) of a 36 bp sized DNA stretch and was further used to determine mt-DNA sub-types, which were described as R(n = 1, 2, or 3). Finally, the P. infestans mt-DNA haplotypes were re-defined as IR(1) or IIR(2) according to PCR derived HVRi and HVRii length polymorphisms. Twenty-three isolates were chosen to verify the feasibility of our new approach for identifying mt-DNA haplotypes and a total of five haplotypes (IR(1), IR(2), IR(3), IIR(2) and IIR(3)) were identified. Additionally, we found that six isolates determined as type I by our method were mistakenly identified as type II by the PCR-RFLP technique. In conclusion, we propose a simple and rapid PCR method for identification of mt-DNA haplotypes based on sequence analyses of the mitochondrial P. infestans genome.

  11. Production of hydrogen peroxide and hydroxyl radical in potato tuber during the necrotrophic phase of hemibiotrophic pathogen Phytophthora infestans infection.

    Science.gov (United States)

    Rastogi, Anshu; Pospíšil, Pavel

    2012-12-05

    In this study, evidence is provided on the formation of hydrogen peroxide (H(2)O(2)) and hydroxyl radical (HO) in the potato tuber during the necrotrophic phase of the hemibiotrophic pathogen Phytophthora infestans infection. Using 3,3-diaminobenzidine tetrahydrochloride (DAB) imaging technique, the formation of H(2)O(2) was demonstrated in P. infestans-infected potato tuber. For the first time, HO formation was demonstrated in P. infestans-infected potato tuber using electron paramagnetic resonance (EPR) spectroscopy. An enhancement in spontaneous ultra-weak photon emission indicated the extent of lipid peroxidation in the P. infestans-infected potato tuber. The data presented in this study reveal that the formation of H(2)O(2) and HO in the P. infestans-infected potato tuber is associated with lipid peroxidation. It is proposed here that the ultra-weak photon emission can be used as a non-invasive indicator of the oxidative processes in the quality control at food industry.

  12. Pseudomonas strains naturally associated with potato plants produce volatiles with high potential for inhibition of Phytophthora infestans.

    Science.gov (United States)

    Hunziker, Lukas; Bönisch, Denise; Groenhagen, Ulrike; Bailly, Aurélien; Schulz, Stefan; Weisskopf, Laure

    2015-02-01

    Bacteria emit volatile organic compounds with a wide range of effects on bacteria, fungi, plants, and animals. The antifungal potential of bacterial volatiles has been investigated with a broad span of phytopathogenic organisms, yet the reaction of oomycetes to these volatile signals is largely unknown. For instance, the response of the late blight-causing agent and most devastating oomycete pathogen worldwide, Phytophthora infestans, to bacterial volatiles has not been assessed so far. In this work, we analyzed this response and compared it to that of selected fungal and bacterial potato pathogens, using newly isolated, potato-associated bacterial strains as volatile emitters. P. infestans was highly susceptible to bacterial volatiles, while fungal and bacterial pathogens were less sensitive. Cyanogenic Pseudomonas strains were the most active, leading to complete growth inhibition, yet noncyanogenic ones also produced antioomycete volatiles. Headspace analysis of the emitted volatiles revealed 1-undecene as a compound produced by strains inducing volatile-mediated P. infestans growth inhibition. Supplying pure 1-undecene to P. infestans significantly reduced mycelial growth, sporangium formation, germination, and zoospore release in a dose-dependent manner. This work demonstrates the high sensitivity of P. infestans to bacterial volatiles and opens new perspectives for sustainable control of this devastating pathogen.

  13. Silencing of DS2 aminoacylase-like genes confirms basal resistance to Phytophthora infestans in Nicotiana benthamiana.

    Science.gov (United States)

    Nakano, Masahito; Nishihara, Masahiro; Yoshioka, Hirofumi; Ohnishi, Kouhei; Hikichi, Yasufumi; Kiba, Akinori

    2014-01-01

    Nicotiana benthamiana is a potential host to several plant pathogens, and immature leaves of N. benthamiana are susceptible to Phytophthora infestans. In contrast, mature leaves of N. benthamiana are weakly susceptible and show basal resistance to P. infestans. We screened a gene-silenced mature plant showing high resistance to P. infestans, designated as DS2 (Disease suppression 2). The deduced amino acid sequence of cDNA responsible for DS2 encoded a putative aminoacylase. Growth of P. infestans decreased in DS2 plants. Trypan blue staining revealed inhibited hyphae growth of P. infestans with an increased number of dead cells under the penetration site in DS2 plants. Consistent with growth inhibition of P. infestans, defense responses such as reactive oxygen generation and expression of a salicylic acid-dependent PR-1a increased markedly in DS2 plants compared with that of control plants. DS2 phenotype was compromised in NahG plants, suggesting DS2 phenotype depends on the salicylic acid signaling pathway. Accelerated defense response was observed in DS2 plants elicited by INF1 elicitin as well as by NbMEK2(DD), which is the constitutive active form of NbMEK2, and act as a downstream regulator of INF1 perception. On the other hand, INF1- and NbMEK2(DD)-induced defense responses were prevented by DS2-overexpressing transgenic tobacco. These results suggest that DS2 negatively regulates plant defense responses against P. infestans via NbMEK2 and SA-dependent signaling pathway in N. benthamiana.

  14. Strain Specific Factors Control Effector Gene Silencing in Phytophthora sojae.

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    Sirjana Devi Shrestha

    Full Text Available The Phytophthora sojae avirulence gene Avr3a encodes an effector that is capable of triggering immunity on soybean plants carrying the resistance gene Rps3a. P. sojae strains that express Avr3a are avirulent to Rps3a plants, while strains that do not are virulent. To study the inheritance of Avr3a expression and virulence towards Rps3a, genetic crosses and self-fertilizations were performed. A cross between P. sojae strains ACR10 X P7076 causes transgenerational gene silencing of Avr3a allele, and this effect is meiotically stable up to the F5 generation. However, test-crosses of F1 progeny (ACR10 X P7076 with strain P6497 result in the release of silencing of Avr3a. Expression of Avr3a in the progeny is variable and correlates with the phenotypic penetrance of the avirulence trait. The F1 progeny from a direct cross of P6497 X ACR10 segregate for inheritance for Avr3a expression, a result that could not be explained by parental imprinting or heterozygosity. Analysis of small RNA arising from the Avr3a gene sequence in the parental strains and hybrid progeny suggests that the presence of small RNA is necessary but not sufficient for gene silencing. Overall, we conclude that inheritance of the Avr3a gene silenced phenotype relies on factors that are variable among P. sojae strains.

  15. Strain Specific Factors Control Effector Gene Silencing in Phytophthora sojae.

    Science.gov (United States)

    Shrestha, Sirjana Devi; Chapman, Patrick; Zhang, Yun; Gijzen, Mark

    2016-01-01

    The Phytophthora sojae avirulence gene Avr3a encodes an effector that is capable of triggering immunity on soybean plants carrying the resistance gene Rps3a. P. sojae strains that express Avr3a are avirulent to Rps3a plants, while strains that do not are virulent. To study the inheritance of Avr3a expression and virulence towards Rps3a, genetic crosses and self-fertilizations were performed. A cross between P. sojae strains ACR10 X P7076 causes transgenerational gene silencing of Avr3a allele, and this effect is meiotically stable up to the F5 generation. However, test-crosses of F1 progeny (ACR10 X P7076) with strain P6497 result in the release of silencing of Avr3a. Expression of Avr3a in the progeny is variable and correlates with the phenotypic penetrance of the avirulence trait. The F1 progeny from a direct cross of P6497 X ACR10 segregate for inheritance for Avr3a expression, a result that could not be explained by parental imprinting or heterozygosity. Analysis of small RNA arising from the Avr3a gene sequence in the parental strains and hybrid progeny suggests that the presence of small RNA is necessary but not sufficient for gene silencing. Overall, we conclude that inheritance of the Avr3a gene silenced phenotype relies on factors that are variable among P. sojae strains.

  16. Genome-wide prediction and functional validation of promoter motifs regulating gene expression in spore and infection stages of Phytophthora infestans.

    Directory of Open Access Journals (Sweden)

    Sourav Roy

    2013-03-01

    Full Text Available Most eukaryotic pathogens have complex life cycles in which gene expression networks orchestrate the formation of cells specialized for dissemination or host colonization. In the oomycete Phytophthora infestans, the potato late blight pathogen, major shifts in mRNA profiles during developmental transitions were identified using microarrays. We used those data with search algorithms to discover about 100 motifs that are over-represented in promoters of genes up-regulated in hyphae, sporangia, sporangia undergoing zoosporogenesis, swimming zoospores, or germinated cysts forming appressoria (infection structures. Most of the putative stage-specific transcription factor binding sites (TFBSs thus identified had features typical of TFBSs such as position or orientation bias, palindromy, and conservation in related species. Each of six motifs tested in P. infestans transformants using the GUS reporter gene conferred the expected stage-specific expression pattern, and several were shown to bind nuclear proteins in gel-shift assays. Motifs linked to the appressoria-forming stage, including a functionally validated TFBS, were over-represented in promoters of genes encoding effectors and other pathogenesis-related proteins. To understand how promoter and genome architecture influence expression, we also mapped transcription patterns to the P. infestans genome assembly. Adjacent genes were not typically induced in the same stage, including genes transcribed in opposite directions from small intergenic regions, but co-regulated gene pairs occurred more than expected by random chance. These data help illuminate the processes regulating development and pathogenesis, and will enable future attempts to purify the cognate transcription factors.

  17. Myb transcription factors and light regulate sporulation in the oomycete Phytophthora infestans.

    Science.gov (United States)

    Xiang, Qijun; Judelson, Howard S

    2014-01-01

    Life cycle progression in eukaryotic microbes is often influenced by environment. In the oomycete Phytophthora infestans, which causes late blight on potato and tomato, sporangia have been reported to form mostly at night. By growing P. infestans under different light regimes at constant temperature and humidity, we show that light contributes to the natural pattern of sporulation by delaying sporulation until the following dark period. However, illumination does not permanently block sporulation or strongly affect the total number of sporangia that ultimately form. Based on measurements of sporulation-induced genes such as those encoding protein kinase Pks1 and Myb transcription factors Myb2R1 and Myb2R3, it appears that most spore-associated transcripts start to rise four to eight hours before sporangia appear. Their mRNA levels oscillate with the light/dark cycle and increase with the amount of sporangia. An exception to this pattern of expression is Myb2R4, which is induced several hours before the other genes and declines after cultures start to sporulate. Transformants over-expressing Myb2R4 produce twice the number of sporangia and ten-fold higher levels of Myb2R1 mRNA than wild-type, and chromatin immunoprecipitation showed that Myb2R4 binds the Myb2R1 promoter in vivo. Myb2R4 thus appears to be an early regulator of sporulation. We attempted to silence eight Myb genes by DNA-directed RNAi, but succeeded only with Myb2R3, which resulted in suppressed sporulation. Ectopic expression studies of seven Myb genes revealed that over-expression frequently impaired vegetative growth, and in the case of Myb3R6 interfered with sporangia dormancy. We observed that the degree of silencing induced by a hairpin construct was correlated with its copy number, and ectopic expression was often unstable due to epigenetic silencing and transgene excision.

  18. Myb transcription factors and light regulate sporulation in the oomycete Phytophthora infestans.

    Directory of Open Access Journals (Sweden)

    Qijun Xiang

    Full Text Available Life cycle progression in eukaryotic microbes is often influenced by environment. In the oomycete Phytophthora infestans, which causes late blight on potato and tomato, sporangia have been reported to form mostly at night. By growing P. infestans under different light regimes at constant temperature and humidity, we show that light contributes to the natural pattern of sporulation by delaying sporulation until the following dark period. However, illumination does not permanently block sporulation or strongly affect the total number of sporangia that ultimately form. Based on measurements of sporulation-induced genes such as those encoding protein kinase Pks1 and Myb transcription factors Myb2R1 and Myb2R3, it appears that most spore-associated transcripts start to rise four to eight hours before sporangia appear. Their mRNA levels oscillate with the light/dark cycle and increase with the amount of sporangia. An exception to this pattern of expression is Myb2R4, which is induced several hours before the other genes and declines after cultures start to sporulate. Transformants over-expressing Myb2R4 produce twice the number of sporangia and ten-fold higher levels of Myb2R1 mRNA than wild-type, and chromatin immunoprecipitation showed that Myb2R4 binds the Myb2R1 promoter in vivo. Myb2R4 thus appears to be an early regulator of sporulation. We attempted to silence eight Myb genes by DNA-directed RNAi, but succeeded only with Myb2R3, which resulted in suppressed sporulation. Ectopic expression studies of seven Myb genes revealed that over-expression frequently impaired vegetative growth, and in the case of Myb3R6 interfered with sporangia dormancy. We observed that the degree of silencing induced by a hairpin construct was correlated with its copy number, and ectopic expression was often unstable due to epigenetic silencing and transgene excision.

  19. Sensitivity to four systemic fungicides of Colombian isolates of Phytophthora infestans

    Directory of Open Access Journals (Sweden)

    Hibert Giovani García

    2008-04-01

    Full Text Available Potato late blight caused by Phytophthora infestans is the most restrictive disease of this crop in Colombia , where environmental conditions are optimal conditions for its epidemic development. This situation leads to an excessive use of fungicides by farmers, which besides representing near 10% of production costs, causes a serious damage of environment and public health. This research pretends to support IPM programs by monitoring the sensitivity levels of 15 isolates of P. infestans obtained from crops in Antioquia, Cundinamarca and Boyacá, to fungicides Ridomil® Gold, Curzate® M-8, Previcur® N SL and Mildex® 711 WG as a tool of the risk analysis that permit to offer to the farmers the technical recommendations based on the generation of sensitivity lines. Evaluations of sensitivity were carried out using the immersion of leaf discs methodology with seven doses of each commercial product. Results show that the studied population presents high levels of sensitivity to these fungicides. In the case of Curzate® M-8, the average EC50 value was 0.28 mg·L-1, while the EC50 for Previcur® N SL reached 0.71 mg·L- . Intests with fungicides Ridomil® Gold and Mildex® 711 WG, these values were 0.62 and 0.54 mg·L-1, respectively. Finally, sporangia production decreased from an average of 41,181 sporangia/mL in control treatment to less than 500 sporangia/mL when the maximum doses of four fungicides were evaluated.

  20. Identification and Characterisation CRN Effectors in Phytophthora capsici Shows Modularity and Functional Diversity

    Science.gov (United States)

    Stam, Remco; Jupe, Julietta; Howden, Andrew J. M.; Morris, Jenny A.; Boevink, Petra C.; Hedley, Pete E.; Huitema, Edgar

    2013-01-01

    Phytophthora species secrete a large array of effectors during infection of their host plants. The Crinkler (CRN) gene family encodes a ubiquitous but understudied class of effectors with possible but as of yet unknown roles in infection. To appreciate CRN effector function in Phytophthora, we devised a simple Crn gene identification and annotation pipeline to improve effector prediction rates. We predicted 84 full-length CRN coding genes and assessed CRN effector domain diversity in sequenced Oomycete genomes. These analyses revealed evidence of CRN domain innovation in Phytophthora and expansion in the Peronosporales. We performed gene expression analyses to validate and define two classes of CRN effectors, each possibly contributing to infection at different stages. CRN localisation studies revealed that P. capsici CRN effector domains target the nucleus and accumulate in specific sub-nuclear compartments. Phenotypic analyses showed that few CRN domains induce necrosis when expressed in planta and that one cell death inducing effector, enhances P. capsici virulence on Nicotiana benthamiana. These results suggest that the CRN protein family form an important class of intracellular effectors that target the host nucleus during infection. These results combined with domain expansion in hemi-biotrophic and necrotrophic pathogens, suggests specific contributions to pathogen lifestyles. This work will bolster CRN identification efforts in other sequenced oomycete species and set the stage for future functional studies towards understanding CRN effector functions. PMID:23536880

  1. Identification and Characterisation CRN Effectors in Phytophthora capsici Shows Modularity and Functional Diversity.

    Directory of Open Access Journals (Sweden)

    Remco Stam

    Full Text Available Phytophthora species secrete a large array of effectors during infection of their host plants. The Crinkler (CRN gene family encodes a ubiquitous but understudied class of effectors with possible but as of yet unknown roles in infection. To appreciate CRN effector function in Phytophthora, we devised a simple Crn gene identification and annotation pipeline to improve effector prediction rates. We predicted 84 full-length CRN coding genes and assessed CRN effector domain diversity in sequenced Oomycete genomes. These analyses revealed evidence of CRN domain innovation in Phytophthora and expansion in the Peronosporales. We performed gene expression analyses to validate and define two classes of CRN effectors, each possibly contributing to infection at different stages. CRN localisation studies revealed that P. capsici CRN effector domains target the nucleus and accumulate in specific sub-nuclear compartments. Phenotypic analyses showed that few CRN domains induce necrosis when expressed in planta and that one cell death inducing effector, enhances P. capsici virulence on Nicotiana benthamiana. These results suggest that the CRN protein family form an important class of intracellular effectors that target the host nucleus during infection. These results combined with domain expansion in hemi-biotrophic and necrotrophic pathogens, suggests specific contributions to pathogen lifestyles. This work will bolster CRN identification efforts in other sequenced oomycete species and set the stage for future functional studies towards understanding CRN effector functions.

  2. The Transcriptome of Compatible and Incompatible Interactions of Potato (Solanum tuberosum) with Phytophthora infestans Revealed by DeepSAGE Analysis

    DEFF Research Database (Denmark)

    Gyetvai, Gabor; Sønderkær, Mads; Göbel, Ulrike

    2012-01-01

    -assissted selection or by transgenic approaches. Specific P. infestans races having the Avr1 effector gene trigger a hypersensitive resistance response in potato plants carrying the R1 resistance gene (incompatible interaction) and cause disease in plants lacking R1 (compatible interaction). The transcriptomes...

  3. Actividad inhibitoria del aceite esencial de Lippia origanoides H.B.K sobre el crecimiento de Phytophthora infestans

    Directory of Open Access Journals (Sweden)

    óscar Arango Bedoya

    2015-04-01

    Full Text Available Phytophthora infestans (Mont. de Bary es el fitopatógeno más perjudicial de la papa (Solanum tuberosum al causar la enfermedad conocida como ‘gota o tizón tardío’. El objetivo de este trabajo fue evaluar la actividad in vitro del aceite esencial obtenido de una especie de orégano silvestre (Lippia origanoides H.B.K. sobre Phytophthora infestans. Para el efecto se evaluaron diferentes concentraciones de este aceite esencial (10, 50, 100, 150, 200, 250 µg/ml y de un fungicida comercial usado como testigo. La actividad antifúngica se determinó con base en la evaluación del crecimiento del micelio mediante el método de dilución en agar tomate. A partir de una concentración de aceite de 150 µg/ml se inhibió completamente el crecimiento del patógeno, por lo que ésta fue considerada como la concentración letal. Este estudio demostró que el aceite esencial de orégano silvestre del Alto Patía, Colombia, es un potencial agente antifúngico que podría ser usado en sistemas de control integrado de P. infestans.

  4. The Arabidopsis lectin receptor kinase LecRK-I.9 enhances resistance to Phytophthora infestans in Solanaceous plants.

    Science.gov (United States)

    Bouwmeester, Klaas; Han, Miao; Blanco-Portales, Rosario; Song, Wei; Weide, Rob; Guo, Li-Yun; van der Vossen, Edwin A G; Govers, Francine

    2014-01-01

    Late blight caused by the plant pathogenic oomycete Phytophthora infestans is known as one of the most destructive potato diseases. Plant breeders tend to employ NB-LRR-based resistance for introducing genetically controlled late blight resistance in their breeding lines. However, P. infestans is able to rapidly escape this type of resistance, and hence, NB-LRR-based resistance in potato cultivars is often not durable. Previously, we identified a novel type of Phytophthora resistance in Arabidopsis. This resistance is mediated by the cell surface receptor LecRK-I.9, which belongs to the family of L-type lectin receptor kinases. In this study, we report that expression of the Arabidopsis LecRK-I.9 gene in potato and Nicotiana benthamiana results in significantly enhanced late blight resistance. Transcriptional profiling showed strong reduction in salicylic acid (SA)-mediated defence gene expression in LecRK-I.9 transgenic potato lines (TPLs). In contrast, transcripts of two protease inhibitor genes accumulated to extreme high levels, suggesting that LecRK-I.9-mediated late blight resistance is relying on a defence response that includes activation of protease inhibitors. These results demonstrate that the functionality of LecRK-I.9 in Phytophthora resistance is maintained after interfamily transfer to potato and N. benthamiana and suggest that this novel type of LecRK-based resistance can be exploited in breeding strategies to improve durable late blight resistance in Solanaceous crops.

  5. Late blight (Phytophthora infestans occurring on stems - a new problem in potato crops

    Directory of Open Access Journals (Sweden)

    Józef Kapsa

    2013-12-01

    Full Text Available In recent years changes in the occurrence of the first potato late blight (Phytophthora infestans symptoms have been noted. Observations of potato crops have showed that occurrence of the blight symptoms is sometimes on the stem instead on the leaves. The aim of the study carried out in 1995-2001 was to determine occurrence and harmfulness of the stem late blight infections. Survey of many potato crops (490 potato fields made in 1997-2001, around Poland enabled assessment of the incidence of stem blight. Average 69,1% of observed crops were affected with stem blight. The stem blight incidence was not connected with the rate of the leaf form of late blight developing on the foliage. Stem form of the disease has appeared more often in the years with less rainfall during June and July. Its occurrence was influenced by micro climate inside potato canopy. Glasshouse experiments confirmed the importance of stem lesions in decreasing tuber yield (11,2-42,9% and increasing tuber infections. Results have shown that tubers contaminated with spores were the least probable source of the stem form of late blight.

  6. Testing Taxonomic Predictivity of Foliar and Tuber Resistance to Phytophthora infestans in Wild Relatives of Potato.

    Science.gov (United States)

    Khiutti, A; Spooner, D M; Jansky, S H; Halterman, D A

    2015-09-01

    Potato late blight, caused by the oomycete phytopathogen Phytophthora infestans, is a devastating disease found in potato-growing regions worldwide. Long-term management strategies to control late blight include the incorporation of host resistance to predominant strains. However, due to rapid genetic changes within pathogen populations, rapid and recurring identification and integration of novel host resistance traits is necessary. Wild relatives of potato offer a rich source of desirable traits, including late blight resistance, but screening methods can be time intensive. We tested the ability of taxonomy, ploidy, crossing group, breeding system, and geography to predict the presence of foliar and tuber late blight resistance in wild Solanum spp. Significant variation for resistance to both tuber and foliar late blight was found within and among species but there was no discernable predictive power based on taxonomic series, clade, ploidy, breeding system, elevation, or geographic location. We observed a moderate but significant correlation between tuber and foliar resistance within species. Although previously uncharacterized sources of both foliar and tuber resistance were identified, our study does not support an assumption that taxonomic or geographic data can be used to predict sources of late blight resistance in wild Solanum spp.

  7. IDENTIFICATION OF KEY MOLECULAR COMPONENTS OF THE RESISTANCE OF CHERRY TOMATO AGAINST Phytophthora infestans

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    LILIANA LÓPEZ KLEINE

    2012-01-01

    Full Text Available El tomate cherry Solanum lycopersicum var cerasiforme cv Matt’s es bastante resistente a la gran parte de aislamientos de Phytophthora infestans. Se han identificado dos aislamientos, US940480 y US970001 que causan interacción incompatible y compatible respectivamente. US970001 es uno de los pocos aislamientos causantes de interacción compatible con este cultivo. Con el fin de identificar genes con expresión diferencial en interacciones compatible e incompatible, analizamos DNA copia de 12899 clones independientes en tres tiempos posteriores a la inoculación del patógeno. Se aplicaron diversas herramientas estadísticas para identificar componentes moleculares claves de la respuesta de la planta al patógeno. Cuarenta y tres genes fueron detectados como activados durante la interacción incompatible a las 36 horas posinoculación, 15 genes se detectaron como activados globalmente tomando en conjunto los 3 tiempos analizados y 12 genes tanto globalmente como a las 36 horas. Análisis de Northern blot permitieron confirmar la expresión diferencial detectada con los análisis de microarreglos y estudiar la expresión diferencial de otros genes de resistencia en plantas (PR en interacciones compatible e incompatible en esta interacción.

  8. Mating Types of Phytophthora infestans Isolates and Their Responses to Metalaxyl and Dimethomorph in Korea

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    Jeom-Soon Kim

    2014-03-01

    Full Text Available Phytophthora infestans was isolated from potato leaves collected from main potato producing areas in Korea during 2009-2011. In 2009, 99 isolates tested were all A1 mating type. Two of 64 isolates in 2010 and two of 78 isolates in 2011 were A2 mating type and they were found only in Miryang area. Among 99 isolates examined in 2009, 13.1% was resistant to metalaxyl, 3.1% was intermediate resistant and 83.8% was sensitive. In 2010, 19.4% of 62 isolates was resistant, 4.8% was intermediate and 75.8% was sensitive. Metalaxyl resistant, intermediate and sensitive isolates collected in 2011 were 23.1%, 9.0% and 67.9%, respectively. Metalaxyl resistant isolates increased mainly in winter cropping areas and seed potato producing areas where fungicides were sprayed more often. Frequencies of isolates showing minimum inhibition concentration of dimethomorph at 1.0-5.0 mg/ml were 17.2% in 2009, 19.0% in 2010 and 15.4% in 2011. However, there was no evidence for occurrence of resistant isolate to dimethomorph because no isolate was able to grow at 5.0 mg/ml.

  9. Late Blight of Potato (Phytophthora infestans I: Fungicides Application and Associated Challenges

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    Abdul Majeed

    2017-03-01

    Full Text Available Potato (Solanum tuberosum L. has been remained an important agricultural crop in resolving global food issues through decades. The crop has experienced enormous growth in terms of production throughout the world in recent decades because of improvement in agricultural mechanization, fertilizers application and irrigation practices. Nevertheless, a significant proportion of this valuable crop is still vulnerable to losses due to prevalence of different viral, bacterial, fungal and nematodes infestations. Late blight, caused by Phytophthora infestans (Mont. de Bary, is one of the most threatening pathogenic diseases which not only results in direct crop losses but also cause farmers to embrace huge monetary expenses for disease control and preventive measures. The disease is well known for notorious ‘Irish Famine’ which resulted in drop of Irish population by more than 20% as result of hunger and potato starvation. Globally, annual losses of crop and money spend on fungicides for late blight control exceeds one trillion US dollars. This paper reviews the significance of late blight of potato and controlling strategies adopted for minimizing yield losses incurred by this disease by the use of synthetic fungicides. Advantages and disadvantages of fungicides application are discussed.

  10. Limited Sexual Reproduction and Quick Turnover in the Population Genetic Structure of Phytophthora infestans in Fujian, China.

    Science.gov (United States)

    Zhu, Wen; Yang, Li-Na; Wu, E-Jiao; Qin, Chun-Fang; Shang, Li-Ping; Wang, Zong-Hua; Zhan, Jiasui

    2015-05-13

    The mating system plays an important role in the spatiotemporal dynamics of pathogen populations through both its direct and indirect impact on the generation and distribution of genetic variation. Here, we used a combination of microsatellite and phenotypic markers to investigate the spatiotemporal distribution of genetic variation in Phytophthora infestans isolates collected from Fujian, China and to determine the role of sexual reproduction in the dynamics. Although the pathogen populations in this region were dominated by self-fertile genotypes, sexual reproduction only occurred occasionally and its contributions to the population genetic structure of P. infestans and epidemics of late blight in the region were limited. Only 49 genotypes were detected among the 534 isolates assayed and the pathogen populations displayed significant heterozygosity excess. Hierarchical analysis revealed that 21.42% of genetic variation was attributed to the difference among sampling years while only 4.45% was attributed to the difference among locations, suggesting temporal factors play a more important role in the population genetic dynamics of P. infestans than spatial factors in this region. We propose that clonal reproduction, combined with founder effects and long distance dispersal of sporangia, is responsible for the observed pattern of spatiotemporal dynamics in P. infestans.

  11. The dihydrolipoyl acyltransferase gene BCE2 participates in basal resistance against Phytophthora infestans in potato and Nicotiana benthamiana.

    Science.gov (United States)

    Wang, Hongyang; Sun, Chunlian; Jiang, Rui; He, Qin; Yang, Yu; Tian, Zhejuan; Tian, Zhendong; Xie, Conghua

    2014-07-01

    Dihydrolipoyl acyltransferase (EC 2.3.1.12), a branched-chain α-ketoacid dehydrogenase E2 subunit (BCE2), catalyzes the transfer of the acyl group from the lipoyl moiety to coenzyme A. However, the role of BCE2 responding to biotic stress in plant is not clear. In this study, we cloned and characterized a BCE2 gene from potato, namely StBCE2, which was previously suggested to be involved in Phytophthora infestans-potato interaction. We found that the expression of StBCE2 was strongly induced by both P. infestans isolate HB09-14-2 and salicylic acid. Besides, when the homolog of StBCE2 in Nicotiana benthamiana named NbBCE2 was silenced, plants showed increased susceptibility to P. infestans and reduced accumulation of hydrogen peroxide (H2O2). Furthermore, we found that a marker gene NbrbohB involved in the production of reactive oxygen species, was also suppressed in NbBCE2-silenced plants. However, silencing of NbBCE2 had no significant effect on the hypersensitive responses trigged by INF1, R3a-AVR3a(KI) pair or Rpi-vnt1.1-AVR-vnt1.1 pair. Our results suggest that BCE2 is associated with the basal resistance to P. infestans by regulating H2O2 production.

  12. Population genetics of Phytophthora infestans in Denmark reveals dominantly clonal populations and specific alleles linked to metalaxyl-M resistance

    DEFF Research Database (Denmark)

    Montes, Melanie Sarah; Nielsen, B.J.; Schmidt, S.G.;

    2016-01-01

    population of P. infestans was characterized over the course of the 2013 growing season, as was the population genetic structure, using simple sequence repeat (SSR) genotypes and single nucleotide polymorphism (SNP)-based mitochondrial haplotyping of over 80 isolates. Both mating types A1 and A2 were present......Control of the potato late blight pathogen Phytophthora infestans relies heavily on chemicals. The fungicide metalaxyl-M (Mefenoxam) has played an important role in controlling the disease, but insensitivity to the fungicide in certain isolates is now of major concern. A genetic basis...... for resistance to metalaxyl suggests the possibility for linking resistance phenotypes to specific population genetic markers, but in order to do this, the population genetic structure and mode of reproduction in a population must first be well described. The dynamics of metalaxyl-M resistance in the Danish...

  13. The efficiency of some fungicides applied to control the Phytophthora infestans (Mont de Bary fungus on potato

    Directory of Open Access Journals (Sweden)

    Daniela POPA

    2008-05-01

    Full Text Available The research was carried on at Targu - Secuiesc within 2002-2004 and its objective was to determine the most efficient fungicides to control the late potato blight caused by the fungus Phytophthora infestans. All the applied products were efficient in controlling the disease in comparison to the untreated control variant.The results of the research show that during the observed period the products Curzate and Acrobat proved to be highly efficient in a constant manner at the three varieties: Ostara, Sante and Desiree. The lowest frequency of infected tubers was registered at the varieties treated with Altima, Acrobat, Tatoo C.

  14. Persistence of the mitochondrial lineage responsible for the Irish potato famine in extant New World Phytophthora infestans

    DEFF Research Database (Denmark)

    Martin, Michael David; Ho, Simon Y W; Wales, Nathan

    2014-01-01

    The plant pathogen Phytophthora infestans emerged in Europe in 1845, triggering the Irish potato famine and massive European potato crop losses that continued until effective fungicides were widely employed in the 20(th) century. Today the pathogen is ubiquitous, with more aggressive and virulent......)-century Europe, three from 1950s U.K. and 34 from modern populations across the New World. We use phylogenetic analyses to identify the HERB-1 lineage in modern populations from both Mexico and South America, and to demonstrate distinct mitochondrial haplotypes were present in 19(th)-century Europe...

  15. The receptor-like kinase SERK3/BAK1 is required for basal resistance against the late blight pathogen phytophthora infestans in Nicotiana benthamiana.

    Directory of Open Access Journals (Sweden)

    Angela Chaparro-Garcia

    Full Text Available BACKGROUND: The filamentous oomycete plant pathogen Phytophthora infestans causes late blight, an economically important disease, on members of the nightshade family (Solanaceae, such as the crop plants potato and tomato. The related plant Nicotiana benthamiana is a model system to study plant-pathogen interactions, and the susceptibility of N. benthamiana to Phytophthora species varies from susceptible to resistant. Little is known about the extent to which plant basal immunity, mediated by membrane receptors that recognise conserved pathogen-associated molecular patterns (PAMPs, contributes to P. infestans resistance. PRINCIPAL FINDINGS: We found that different species of Phytophthora have varying degrees of virulence on N. benthamiana ranging from avirulence (incompatible interaction to moderate virulence through to full aggressiveness. The leucine-rich repeat receptor-like kinase (LRR-RLK BAK1/SERK3 is a major modulator of PAMP-triggered immunity (PTI in Arabidopsis thaliana and N. benthamiana. We cloned two NbSerk3 homologs, NbSerk3A and NbSerk3B, from N. benthamiana based on sequence similarity to the A. thaliana gene. N. benthamiana plants silenced for NbSerk3 showed markedly enhanced susceptibility to P. infestans infection but were not altered in resistance to Phytophthora mirabilis, a sister species of P. infestans that specializes on a different host plant. Furthermore, silencing of NbSerk3 reduced the cell death response triggered by the INF1, a secreted P. infestans protein with features of PAMPs. CONCLUSIONS/SIGNIFICANCE: We demonstrated that N. benthamiana NbSERK3 significantly contributes to resistance to P. infestans and regulates the immune responses triggered by the P. infestans PAMP protein INF1. In the future, the identification of novel surface receptors that associate with NbSERK3A and/or NbSERK3B should lead to the identification of new receptors that mediate recognition of oomycete PAMPs, such as INF1.

  16. Evaluación de marcadores moleculares asociados con resistencia a gota (Phytophthora infestans L. en papas diploides y tetraploides

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    D. K. Juyó

    2012-06-01

    Full Text Available Normal 0 21 false false false ES-CO X-NONE X-NONE MicrosoftInternetExplorer4 Título en ingles: Evaluation of molecular markers associated with resistance to late blight (Phytophthora infestans L.  in diploid and tetraploid potatoes Resumen La papa, cultivo de importancia a nivel mundial es gravemente afectado por gota, enfermedad ocasionada por el oomycete Phytophthora infestans. Actualmente la forma más efectiva para combatir la enfermedad es mediante el desarrollo de cultivares resistentes al patógeno. Para esto, una estrategia es identificar genes que confieran resistencia al patógeno, para lo cual se buscan marcadores asociados con el carácter de resistencia. En este estudio se evaluaron marcadores moleculares tipo SCAR (Sequence Characterized Amplified Region: CosA, GP179, BA47f2 y Prp1 asociados con resistencia a P. infestans y el gen de resistencia R1, en 22 cultivares tetraploides pertenecientes a la subespecie andigena y cinco especies silvestres. Se evaluó el polimorfismo y se determinó si los alelos polimórficos permitían diferenciar genotipos resistentes de susceptibles. Se comparó el  tamaño de los fragmentos obtenidos con los fragmentos esperados asociados con resistencia de acuerdo a reportes. El análisis se realizó considerando presencia/ausencia de los fragmentos: CosA210, CosA250, R11400, R11800, BA47f2500, GP179570, Prp1300, Prp1600, y Prp1900. Los resultados indicaron que en los cultivares tetraploides y silvestres, se presentaron polimorfismos en todos los marcadores evaluados, con excepción del marcador GP179. No se encontró correlación entre el rasgo de resistencia y los alelos. Los resultados de este estudio muestran que hay repuesta diferencial a los marcadores entre las subsp. tuberosum y subsp. Andigena.   Palabras clave: Phytophthora infestans, resistencia a gota, marcadores diagnóstico, Solanum tuberosum subsp. Andigena. Abstract Potato is an important worldwide crop seriously affected by late

  17. Role of the cyclic lipopeptide massetolide A in biological control of Phytophthora infestans and in colonization of tomato plants by Pseudomonas fluorescens

    NARCIS (Netherlands)

    Tran, H.; Ficke, A.; Asiimwe, T.; Höfte, M.; Raaijmakers, J.M.

    2007-01-01

    Pseudomonas strains have shown promising results in biological control of late blight caused by Phytophthora infestans. However, the mechanism(s) and metabolites involved are in many cases poorly understood. Here, the role of the cyclic lipopeptide massetolide A of Pseudomonas fluorescens SS101 in b

  18. An ancient R gene from Solanum bulbocastanum confers broad-spectrum resistance to late Phytophthora infestans in cultivated potato and tomato

    NARCIS (Netherlands)

    Vossen, van der E.A.G.; Sikkema, A.; Lintel Hekkert, te B.; Gross, J.; Stevens, P.; Muskens, M.; Wouters, T.C.A.E.; Pereira, A.B.; Stiekema, W.J.; Allefs, S.

    2003-01-01

    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 Rp

  19. Albugo-imposed changes to tryptophan- derived antimicrobial metabolite biosynthesis may contribute to suppression of non-host resistance to Phytophthora infestans in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    prince, David; Rallapalli, Ghanasyam; Xu, Deyang

    2017-01-01

    by Albugo species can overcome non-host resistance and enable secondary infection and reproduction of usually non-virulent pathogens, including the potato late blight pathogen Phytophthora infestans on Arabidopsis thaliana. However, the molecular basis of host defense suppression in this complex plant–microbe...... interaction is unclear. Here, we investigate specific defense mechanisms in Arabidopsis that are suppressed by Albugo infection....

  20. Revealing the importance of meristems and roots for the development of hypersensitive responses and full foliar resistance to Phytophthora infestans in the resistant potato cultivar Sarpo Mira

    DEFF Research Database (Denmark)

    Orlowska, Elzbieta Zofia; Basile, Alessio; Kandzia, Izabela

    2012-01-01

    The defence responses of potato against Phytophthora infestans were studied using the highly resistant Sarpo Mira cultivar. The effects of plant integrity, meristems, and roots on the hypersensitive response (HR), plant resistance, and the regulation of PR genes were analysed. Sarpo Mira shoots a...

  1. The population structure of Phytophthora infestans from the Toluca Valley of Central Mexico suggests genetic differentiation between populations from cultivated potato and wild Solanum spp.

    NARCIS (Netherlands)

    Flier, W.G.; Grünwald, N.J.; Kroon, L.P.N.M.; Sturbaum, A.K.; Bosch, van den G.B.M.; Garay-Serrano, E.; Lozoya-Saldaña, H.; Fry, W.E.; Turkensteen, L.J.

    2003-01-01

    The Population structure of Phytophthora infestans in the Toluca Valley of central Mexico was assessed using 170 isolates collected front cultivated potatoes and the native wild Solanum spp., S. demissum and S. xedinense. All isolates were analyzed for mitochondrial DNA (mtDNA) haplotype and amplifi

  2. Effects of latrunculin B on the actin cytoskeleton and hyphal growth in Phytophthora infestans.

    Science.gov (United States)

    Ketelaar, Tijs; Meijer, Harold J G; Spiekerman, Marjolein; Weide, Rob; Govers, Francine

    2012-12-01

    The actin cytoskeleton is conserved in all eukaryotes, but its functions vary among different organisms. In oomycetes, the function of the actin cytoskeleton has received relatively little attention. We have performed a bioinformatics study and show that oomycete actin genes fall within a distinct clade that is divergent from plant, fungal and vertebrate actin genes. To obtain a better understanding of the functions of the actin cytoskeleton in hyphal growth of oomycetes, we studied the actin organization in Phytophthora infestans hyphae and the consequences of treatment with the actin depolymerising drug latrunculin B (latB). This revealed that latB treatment causes a concentration dependent inhibition of colony expansion and aberrant hyphal growth. The most obvious aberrations observed upon treatment with 0.1 μM latB were increased hyphal branching and irregular tube diameters whereas at higher concentrations latB (0.5 and 1 μM) tips of expanding hyphae changed into balloon-like shapes. This aberrant growth correlated with changes in the organization of the actin cytoskeleton. In untreated hyphae, staining with fluorescently tagged phalloidin revealed two populations of actin filaments: long, axially oriented actin filament cables and cortical actin filament plaques. Two hyphal subtypes were recognized, one containing only plaques and the other containing both cables and plaques. In the latter, some hyphae had an apical zone without actin filament plaques. Upon latB treatment, the proportion of hyphae without actin filament cables increased and there were more hyphae with a short apical zone without actin filament plaques. In general, actin filament plaques were more resilient against actin depolymerisation than actin filament cables. Besides disturbing hyphal growth and actin organization, actin depolymerisation also affected the positioning of nuclei. In the presence of latB, the distance between nuclei and the hyphal tip decreased, suggesting that the actin

  3. Production of Phytophthora infestans-resistant potato (Solanum tuberosum) utilising Ensifer adhaerens OV14.

    Science.gov (United States)

    Wendt, Toni; Doohan, Fiona; Mullins, Ewen

    2012-06-01

    Based on the use of Agrobacterium tumefaciens-mediated transformation commodity crop improvement through genetic engineering is the fastest adopted crop technology in the world (James 2010). However, the complexity of the Agrobacterium patent landscape remains a challenge for non-patent holders who wish to generate novel varieties for a commercial purpose. The potential of non-Agrobacterium strains (Transbacter(™)) to modify a plant genome has previously been described. However, they are unlikely to be widely used without significant adjustments in transformation protocols in order to improve their gene transfer efficiencies. In this study we set out to identify alternative bacteria species that could (a) utilize vir genes for genetic transformation and (b) substitute for A. tumefaciens in existing transformation protocols, without a prerequisite for protocol modifications. To this end we isolated a collection (n=751) of plant-associated bacteria from the rhizosphere of commercially grown crops. Based on various screens, including plant transformation with the open-source vector pCAMBIA5105, we identified a strain of the bacterium Ensifer adhaerens with the capacity to transform both Arabidopsis thaliana (0.12%) and potato (mean transformation frequency 35.1%). Thereafter, Ensifer adhaerens was used to generate blight- (causative organism Phytophthora infestans) resistant potato using the Solanum bulbocastanum 'resistance to blight' (RB) gene. Resistant genotypes were confirmed by associated molecular analysis and resistant phenotypes demonstrated by the development of hypersensitive lesions on inoculated leaf tissue post-pathogen inoculation. These data confirm the potential of Ensifer-mediated transformation (EMT) as a novel platform for the high frequency generation of transgenic potato.

  4. A simple method for diagnostic of Phytophthora infestans (Mont. de Bary from potato agricultural fields of potato

    Directory of Open Access Journals (Sweden)

    Touseef Hussain

    2015-12-01

    Full Text Available A correct detection and appropriate identification of causal pathogens associated with crop plants or seeds are considered to be the most important issue in designing the proper management plans for plant diseases. This study was designed to detect Phytophthora infestans inoculum from potato grown soil. A high detection rate of P.infestans was obtained from the naturally infested soil of potato fields. Naturally soils were firstly moistened in a plastic pots and then pre-incubated at ±18°C for 3 days, baiting with potato tuber slice for 24, 48, and 72 h. The baits were then thoroughly washed, flooded with 10–15 ml of distilled water in Petri-dishes and incubated under continuous darkness in chamber ±18ºC. Sporangia started to emerge from the margins of potato tuber slice. They were easily observed under the stereomicroscope. Pure culture of the fungus was obtained by isolating from baited tubers on a Rye Agar medium. This is the first report of recovery of P. infestans from naturally infested potato growing soils using susceptible potato tuber (K. Bahar as bait in India. All isolates were determined to be A2 mating type.

  5. Characterization of three novel desaturases involved in the delta-6 desaturation pathways for polyunsaturated fatty acid biosynthesis from Phytophthora infestans.

    Science.gov (United States)

    Sun, Quanxi; Liu, Jiang; Zhang, Qin; Qing, Xiaohe; Dobson, Gary; Li, Xinzheng; Qi, Baoxiu

    2013-09-01

    Phytophthora infestans is the causative agent of potato blight that resulted in the great famine in Ireland in the nineteenth century. This microbe can release large amounts of the C20 very long-chain polyunsaturated fatty acids arachidonic acid (ARA; 20:4Δ(5, 8, 11, 14)) and eicosapentaenoic acid (EPA; 20:5Δ(5, 8, 11, 14, 17)) upon invasion that is known to elicit a hypersensitive response to their host plant. In order to identify enzymes responsible for the biosynthesis of these fatty acids, we blasted the recently fully sequenced P. infestans genome and identified three novel putatively encoding desaturase sequences. These were subsequently functionally characterized by expression in Saccharomyces cerevisiae and confirmed that they encode desaturases with Δ12, Δ6 and Δ5 activity, designated here as PinDes12, PinDes6 and PinDes5, respectively. This, together with the combined fatty acid profiles and a previously identified Δ6 elongase activity, implies that the ARA and EPA are biosynthesized predominantly via the Δ6 desaturation pathways in P. infestans. Elucidation of ARA and EPA biosynthetic mechanism may provide new routes to combating this potato blight microbe directly or by means of conferring resistance to important crops.

  6. Normoergic NO-dependent changes, triggered by a SAR inducer in potato, create more potent defense responses to Phytophthora infestans.

    Science.gov (United States)

    Janus, Łukasz; Milczarek, Grzegorz; Arasimowicz-Jelonek, Magdalena; Abramowski, Dariusz; Billert, Hanna; Floryszak-Wieczorek, Jolanta

    2013-10-01

    In our experimental approach we examined how potato leaves exposed to a chemical agent might induce nitric oxide (NO) dependent biochemical modifications for future mobilization of an effective resistance to Phytophthora infestans. After potato leaf treatment with one of the following SAR inducers, i.e. β-aminobutyric acid (BABA), 2,6-dichloroisonicotinic acid (INA) or Laminarin, we observed enhanced NO generation concomitant with biochemical changes related to a slight superoxide anion (O2(-)) and hydrogen peroxide (H2O2) accumulation dependent on minimal NADPH oxidase and peroxidase activities, respectively. These rather normoergic changes, linked to the NO message, were mediated by the temporary down-regulation of S-nitrosoglutathione reductase (GSNOR). In turn, after challenge inoculation signal amplification promoted potato resistance manifested in the up-regulation of GSNOR activity tuned with the depletion of the SNO pool, which was observed by our team earlier (Floryszak-Wieczorek et al., 2012). Moreover, hyperergic defense responses related to an early and rapid O2(-)and H2O2 overproduction together with a temporary increase in NADPH oxidase and peroxidase activities were noted. BABA treatment was the most effective against P. infestans resulting in the enhanced activity of β-1,3-glucanase and callose deposition. Our results indicate that NO-mediated biochemical modifications might play an important role in creating more potent defense responses of potato to a subsequent P. infestans attack.

  7. Comparative analyses of fungicide sensitivity and SSR marker variations indicate a low risk of developing azoxystrobin resistance in Phytophthora infestans.

    Science.gov (United States)

    Qin, Chun-Fang; He, Meng-Han; Chen, Feng-Ping; Zhu, Wen; Yang, Li-Na; Wu, E-Jiao; Guo, Zheng-Liang; Shang, Li-Ping; Zhan, Jiasui

    2016-02-08

    Knowledge of the evolution of fungicide resistance is important in securing sustainable disease management in agricultural systems. In this study, we analyzed and compared the spatial distribution of genetic variation in azoxystrobin sensitivity and SSR markers in 140 Phytophthora infestans isolates sampled from seven geographic locations in China. Sensitivity to azoxystrobin and its genetic variation in the pathogen populations was measured by the relative growth rate (RGR) at four fungicide concentrations and determination of the effective concentration for 50% inhibition (EC50). We found that all isolates in the current study were sensitive to azoxystrobin and their EC50 was similar to that detected from a European population about 20 years ago, suggesting the risk of developing azoxystrobin resistance in P. infestans populations is low. Further analyses indicate that reduced genetic variation and high fitness cost in resistant mutations are the likely causes for the low evolutionary likelihood of developing azoxystrobin resistance in the pathogen. We also found a negative correlation between azoxystrobin tolerance in P. infestans populations and the mean annual temperature of collection sites, suggesting that global warming may increase the efficiency of using the fungicide to control the late blight.

  8. The Ph-3 gene from Solanum pimpinellifolium encodes CC-NBS-LRR protein conferring resistance to Phytophthora infestans.

    Science.gov (United States)

    Zhang, Chunzhi; Liu, Lei; Wang, Xiaoxuan; Vossen, Jack; Li, Guangcun; Li, Tao; Zheng, Zheng; Gao, Jianchang; Guo, Yanmei; Visser, Richard G F; Li, Junming; Bai, Yuling; Du, Yongchen

    2014-06-01

    Ph-3 is the first cloned tomato gene for resistance to late blight and encodes a CC-NBS-LRR protein. Late blight, caused by Phytophthora infestans, is one of the most destructive diseases in tomato. The resistance (R) gene Ph-3, derived from Solanum pimpinellifolium L3708, provides resistance to multiple P. infestans isolates and has been widely used in tomato breeding programmes. In our previous study, Ph-3 was mapped into a region harbouring R gene analogues (RGA) at the distal part of long arm of chromosome 9. To further narrow down the Ph-3 interval, more recombinants were identified using the flanking markers G2-4 and M8-2, which defined the Ph-3 gene to a 26 kb region according to the Heinz1706 reference genome. To clone the Ph-3 gene, a bacterial artificial chromosome (BAC) library was constructed using L3708 and one BAC clone B25E21 containing the Ph-3 region was identified. The sequence of the BAC clone B25E21 showed that only one RGA was present in the target region. A subsequent complementation analysis demonstrated that this RGA, encoding a CC-NBS-LRR protein, was able to complement the susceptible phenotype in cultivar Moneymaker. Thus this RGA was considered the Ph-3 gene. The predicted Ph-3 protein shares high amino acid identity with the chromosome-9-derived potato resistance proteins against P. infestans (Rpi proteins).

  9. Phytophthora effector targets a novel component of small RNA pathway in plants to promote infection.

    Science.gov (United States)

    Qiao, Yongli; Shi, Jinxia; Zhai, Yi; Hou, Yingnan; Ma, Wenbo

    2015-05-05

    A broad range of parasites rely on the functions of effector proteins to subvert host immune response and facilitate disease development. The notorious Phytophthora pathogens evolved effectors with RNA silencing suppression activity to promote infection in plant hosts. Here we report that the Phytophthora Suppressor of RNA Silencing 1 (PSR1) can bind to an evolutionarily conserved nuclear protein containing the aspartate-glutamate-alanine-histidine-box RNA helicase domain in plants. This protein, designated PSR1-Interacting Protein 1 (PINP1), regulates the accumulation of both microRNAs and endogenous small interfering RNAs in Arabidopsis. A null mutation of PINP1 causes embryonic lethality, and silencing of PINP1 leads to developmental defects and hypersusceptibility to Phytophthora infection. These phenotypes are reminiscent of transgenic plants expressing PSR1, supporting PINP1 as a direct virulence target of PSR1. We further demonstrate that the localization of the Dicer-like 1 protein complex is impaired in the nucleus of PINP1-silenced or PSR1-expressing cells, indicating that PINP1 may facilitate small RNA processing by affecting the assembly of dicing complexes. A similar function of PINP1 homologous genes in development and immunity was also observed in Nicotiana benthamiana. These findings highlight PINP1 as a previously unidentified component of RNA silencing that regulates distinct classes of small RNAs in plants. Importantly, Phytophthora has evolved effectors to target PINP1 in order to promote infection.

  10. The Potato ERF Transcription Factor StERF3 Negatively Regulates Resistance to Phytophthora infestans and Salt Tolerance in Potato.

    Science.gov (United States)

    Tian, Zhendong; He, Qin; Wang, Haixia; Liu, Ying; Zhang, Ying; Shao, Fang; Xie, Conghua

    2015-05-01

    Ethylene response factors (ERFs) are unique to the plant kingdom and play crucial roles in plant response to various biotic and abiotic stresses. We show here that a potato StERF3, which contains an ERF-associated amphiphilic repression (EAR) motif in its C-terminal region, negatively regulates resistance to Phytophthora infestans and salt tolerance in potato. The StERF3 promoter responds to induction by salicylic acid, ABA ethylene and NaCl, as well as P. infestans, the causal agent of potato late blight disease. StERF3 could bind to the GCC box element of the HIS3 promoter and activate transcription of HIS3 in yeast cells. Importantly, silencing of StERF3 in potato produced an enhanced foliage resistance to P. infestans and elevated plant tolerance to NaCl stress accompanied by the activation of defense-related genes (PR1, NPR1 and WRKY1). In contrast, StERF3-overexpressing plants showed reduced expression of these defense-related genes and enhanced susceptibility to P. infestans, suggesting that StERF3 functions as a negative regulator of downstream defense- and/or stress-related genes in potato. StERF3 is localized to the nucleus. Interestingly, yeast two-hybrid assay and a bimolecular fluorescence complementation (BiFC) test clarified that StERF3 could interact with other proteins in the cytoplasm which may lead to its re-localization between the nucleus and cytoplasm, revealing a novel means of StERF3 regulation. Taken together, these data provide new insights into the mechanism underlying how StERF3 negatively regulates late blight resistance and abiotic tolerance in potato and may have a potential use in engineering late blight resistance in potato.

  11. Quantitative Resistance of Potato to Pectobacterium atrosepticum and Phytophthora infestans: Integrating PAMP-Triggered Response and Pathogen Growth

    Science.gov (United States)

    Kröner, Alexander; Hamelin, Gaëlle; Andrivon, Didier; Val, Florence

    2011-01-01

    While the mechanisms underlying quantitative resistance of plants to pathogens are still not fully elucidated, the Pathogen-Associated Molecular Patterns (PAMPs)-triggered response model suggests that such resistance depends on a dynamic interplay between the plant and the pathogen. In this model, the pathogens themselves or elicitors they produce would induce general defense pathways, which in turn limit pathogen growth and host colonisation. It therefore suggests that quantitative resistance is directly linked to a common set of general host defense mechanisms, but experimental evidence is still inconclusive. We tested the PAMP-triggered model using two pathogens (Pectobacterium atrosepticum and Phytophthora infestans) differing by their infectious processes and five potato cultivars spanning a range of resistance levels to each pathogen. Phenylalanine ammonia-lyase (PAL) activity, used as a defense marker, and accumulation of phenolics were measured in tuber slices challenged with lipopolysaccharides from P. atrosepticum or a concentrated culture filtrate from P. infestans. PAL activity increased following treatment with the filtrate but not with lipopolysaccharides, and varied among cultivars. It was positively related to tuber resistance to P. atrosepticum, but negatively related to tuber resistance to P. infestans. It was also positively related to the accumulation of total phenolics. Chlorogenic acid, the main phenolic accumulated, inhibited growth of both pathogens in vitro, showing that PAL induction caused active defense against each of them. Tuber slices in which PAL activity had been induced before inoculation showed increased resistance to P. atrosepticum, but not to P. infestans. Our results show that inducing a general defense mechanism does not necessarily result in quantitative resistance. As such, they invalidate the hypothesis that the PAMP-triggered model alone can explain quantitative resistance. We thus designed a more complex model

  12. Quantitative resistance of potato to Pectobacterium atrosepticum and Phytophthora infestans: integrating PAMP-triggered response and pathogen growth.

    Directory of Open Access Journals (Sweden)

    Alexander Kröner

    Full Text Available While the mechanisms underlying quantitative resistance of plants to pathogens are still not fully elucidated, the Pathogen-Associated Molecular Patterns (PAMPs-triggered response model suggests that such resistance depends on a dynamic interplay between the plant and the pathogen. In this model, the pathogens themselves or elicitors they produce would induce general defense pathways, which in turn limit pathogen growth and host colonisation. It therefore suggests that quantitative resistance is directly linked to a common set of general host defense mechanisms, but experimental evidence is still inconclusive. We tested the PAMP-triggered model using two pathogens (Pectobacterium atrosepticum and Phytophthora infestans differing by their infectious processes and five potato cultivars spanning a range of resistance levels to each pathogen. Phenylalanine ammonia-lyase (PAL activity, used as a defense marker, and accumulation of phenolics were measured in tuber slices challenged with lipopolysaccharides from P. atrosepticum or a concentrated culture filtrate from P. infestans. PAL activity increased following treatment with the filtrate but not with lipopolysaccharides, and varied among cultivars. It was positively related to tuber resistance to P. atrosepticum, but negatively related to tuber resistance to P. infestans. It was also positively related to the accumulation of total phenolics. Chlorogenic acid, the main phenolic accumulated, inhibited growth of both pathogens in vitro, showing that PAL induction caused active defense against each of them. Tuber slices in which PAL activity had been induced before inoculation showed increased resistance to P. atrosepticum, but not to P. infestans. Our results show that inducing a general defense mechanism does not necessarily result in quantitative resistance. As such, they invalidate the hypothesis that the PAMP-triggered model alone can explain quantitative resistance. We thus designed a more complex

  13. Quantitative resistance of potato to Pectobacterium atrosepticum and Phytophthora infestans: integrating PAMP-triggered response and pathogen growth.

    Science.gov (United States)

    Kröner, Alexander; Hamelin, Gaëlle; Andrivon, Didier; Val, Florence

    2011-01-01

    While the mechanisms underlying quantitative resistance of plants to pathogens are still not fully elucidated, the Pathogen-Associated Molecular Patterns (PAMPs)-triggered response model suggests that such resistance depends on a dynamic interplay between the plant and the pathogen. In this model, the pathogens themselves or elicitors they produce would induce general defense pathways, which in turn limit pathogen growth and host colonisation. It therefore suggests that quantitative resistance is directly linked to a common set of general host defense mechanisms, but experimental evidence is still inconclusive. We tested the PAMP-triggered model using two pathogens (Pectobacterium atrosepticum and Phytophthora infestans) differing by their infectious processes and five potato cultivars spanning a range of resistance levels to each pathogen. Phenylalanine ammonia-lyase (PAL) activity, used as a defense marker, and accumulation of phenolics were measured in tuber slices challenged with lipopolysaccharides from P. atrosepticum or a concentrated culture filtrate from P. infestans. PAL activity increased following treatment with the filtrate but not with lipopolysaccharides, and varied among cultivars. It was positively related to tuber resistance to P. atrosepticum, but negatively related to tuber resistance to P. infestans. It was also positively related to the accumulation of total phenolics. Chlorogenic acid, the main phenolic accumulated, inhibited growth of both pathogens in vitro, showing that PAL induction caused active defense against each of them. Tuber slices in which PAL activity had been induced before inoculation showed increased resistance to P. atrosepticum, but not to P. infestans. Our results show that inducing a general defense mechanism does not necessarily result in quantitative resistance. As such, they invalidate the hypothesis that the PAMP-triggered model alone can explain quantitative resistance. We thus designed a more complex model

  14. VARIABILIDAD GENÉTICA DE AISLAMIENTOS COLOMBIANOS DE Phytophthora infestans (Mont de Bary EN SOLANÁCEAS CULTIVADAS EN COLOMBIA GENETIC VARIABILITY OF ISOLATES OF Phytophthora infestans (Mont. de Bary IN SOLANACEOUS CROPS FROM COLOMBIA

    Directory of Open Access Journals (Sweden)

    Natalia Raigosa Gómez

    2009-06-01

    Full Text Available Se estudio el nivel de variabilidad genética de una población de 35 aislamientos de Phytophthora infestans obtenidos en diferentes hospedantes y regiones geográficas de Colombia, mediante las técnicas de haplotipos mitocondriales y RAPD. Los resultados encontrados sugieren la existencia en el país de los haplotipos mitocondriales Ia en los aislamientos que afectan tomate de árbol (Solanum betaceum y IIa en cultivos de papa; dichos haplotipos están asociados a los linajes genéticos EC-3 y EC-1, respectivamente. Sin embargo, tres aislamientos obtenidos en tomate de mesa (S. lycopersicum, pimentón (Capsicum sp. y pepino de agua (S. muricatum requieren de un análisis posterior, debido a la falta de correlación entre los perfiles de restricción generados con los cuatro pares de cebadores utilizados en esta prueba y los haplotipos mitocondriales mencionados en la literatura. De otra parte, mediante cuatro cebadores RAPD, fue posible encontrar variabilidad al interior de los dos linajes genéticos, siendo interesante el hecho que los aislamientos obtenidos en tomate de árbol (EC-3 fueron divididos en dos grupos, relacionados con una distancia genética de 0,17. Estos hallazgos indican que es importante contemplar las fuentes de variación asexual en el análisis de la estructura poblacional de este oomycete y por tanto en el diseño de las estrategias de control de las enfermedades que causa P. infestans en cultivos de solanáceas de importancia económica.The level of genetic variability of 35 isolates of Phytophthora infestans obtained from different hosts and geographical regions of Colombia was studied through mitochondrial haplotypes and RAPD techniques. Results suggested the existence of mitochondrial haplotypes Ia affecting tree tomato (Solanum betaceum and IIa in potato, which are associated with genetic lineages EC-3 and EC-1, respectively. However, three isolates obtained from tomato (S. lycopersicum, capsicum (Capsicum sp. and

  15. Assessment of metabolic capacity of Trichoderma inhamatum Bol12 QD biocontrol on native strains of Phytophthora infestans in vitro

    Directory of Open Access Journals (Sweden)

    Puño Ramon

    2011-08-01

    Full Text Available Plant pathogen Phytophthora infestans is a cause of decreased crop yield of tomato, to control these losses, farmers use chemicals. This has consequences for the environment, human health and beneficial organisms in the ecosystem. The objective was to obtain and identify native isolates of Trichoderma spp. In soil planted with tomato Tlayacapan, Morelos (Mexico, Alternaria solani problems and Phytophthora infestans, also determine their antagonistic capacity in vitro. Trichoderma was isolated directly from soil by dilution in culture medium plate with potato dextrose agar (PDA. On the other side plate dilutions of yeast T. QD Bol12 inhamatum crops produced in batch for 30 days to compare the effectiveness of biocontrol. The filtered yeast inhibited mycelial growth kinetic of the agent in laboratory with the 1:2 dilution growth was 32.5% for the 1:4 dilution mycelial growth was 69.1% and finally to the dilution of 1:8 of the yeast biocontrol mycelium grew to 95.2%. To demonstrate the inhibitory activity on the pathogen in field crops, there were 3 L batch for four months. The application of three doses (undiluted, diluted 1:2 and 1:4 plus a control dilution water only was performed in a complete block design with four replications randomly with the tomato crop, belonging to the variety Santa Cruz Kada Gigante in the plots of the Academic Rural United Campesina Carmen Pampa. Statistical analysis by Duncan's test showed that the pure leaven reduce infection by Phytophthora infestans significantly in tomato. Appeared another tomato plant pathogen, Septoria lycopersici, in the course of fieldwork. We also evaluated the effect of the dose of yeast to this disease, and also noticed a significant reduction with all doses of yeast. These experiments demonstrated that the seeds of T. QD Bol12 inhamatum have biocontrol effect on the tomato crop. The antagonistic capacity was assessed using the cellophane and the kind of antagonism with the dual culture

  16. A Phytophthora sojae effector suppresses endoplasmic reticulum stress-mediated immunity by stabilizing plant Binding immunoglobulin Proteins

    Science.gov (United States)

    Jing, Maofeng; Guo, Baodian; Li, Haiyang; Yang, Bo; Wang, Haonan; Kong, Guanghui; Zhao, Yao; Xu, Huawei; Wang, Yan; Ye, Wenwu; Dong, Suomeng; Qiao, Yongli; Tyler, Brett M.; Ma, Wenbo; Wang, Yuanchao

    2016-01-01

    Phytophthora pathogens secrete an array of specific effector proteins to manipulate host innate immunity to promote pathogen colonization. However, little is known about the host targets of effectors and the specific mechanisms by which effectors increase susceptibility. Here we report that the soybean pathogen Phytophthora sojae uses an essential effector PsAvh262 to stabilize endoplasmic reticulum (ER)-luminal binding immunoglobulin proteins (BiPs), which act as negative regulators of plant resistance to Phytophthora. By stabilizing BiPs, PsAvh262 suppresses ER stress-triggered cell death and facilitates Phytophthora infection. The direct targeting of ER stress regulators may represent a common mechanism of host manipulation by microbes. PMID:27256489

  17. Mutations in the EDR1 Gene Alter the Response of Arabidopsis thaliana to Phytophthora infestans and the Bacterial PAMPs flg22 and elf18.

    Science.gov (United States)

    Geissler, Katrin; Eschen-Lippold, Lennart; Naumann, Kai; Schneeberger, Korbinian; Weigel, Detlef; Scheel, Dierk; Rosahl, Sabine; Westphal, Lore

    2015-02-01

    Mechanistically, nonhost resistance of Arabidopsis thaliana against the oomycete Phytophthora infestans is not well understood. Besides PEN2 and PEN3, which contribute to penetration resistance, no further components have been identified so far. In an ethylmethane sulphonate-mutant screen, we mutagenized pen2-1 and screened for mutants with an altered response to infection by P. infestans. One of the mutants obtained, enhanced response to Phytophthora infestans6 (erp6), was analyzed. Whole-genome sequencing of erp6 revealed a single nucleotide polymorphism in the coding region of the kinase domain of At1g08720, which encodes the putative MAPKKK ENHANCED DISEASE RESISTANCE1 (EDR1). We demonstrate that three independent lines with knock-out alleles of edr1 mount an enhanced response to P. infestans inoculation, mediated by increased salicylic acid signaling and callose deposition. Moreover, we show that the single amino acid substitution in erp6 causes the loss of in vitro autophosphorylation activity of EDR1. Furthermore, growth inhibition experiments suggest a so-far-unknown involvement of EDR1 in the response to the pathogen-associated molecular patterns flg22 and elf18. We conclude that EDR1 contributes to the defense response of A. thaliana against P. infestans. Our data position EDR1 as a negative regulator in postinvasive nonhost resistance.

  18. CARACTERIZACIÓN DE POBLACIONES DE Phytophthora infestans (MONT, DE BARY) OBTENIDAS DE Solanum TRANSGÉNICAS Y DE HÍBRIDOS SOMÁTICOS RESISTENTES

    OpenAIRE

    Hector Lozoya-Saldaña

    2010-01-01

    En el valle de Toluca, México, durante el verano de 2003, clones obtenidos por ingeniería genética y por hibridación somática entre Solanum tuberosum y S. bulbocastanum fueron expuestos a infección natural por Phytophthora infestans, a fin de cuantificar su resistencia al oomiceto, previamente comprobada en otras condiciones. El objetivo fue identificar los genotipos de P. infestans que selectiva y progresivamente infectaron a los clones de papa. La mayoría de éstos fueron resistentes en los ...

  19. The lectin receptor kinase LecRK-I.9 is a novel Phytophthora resistance component and a potential host target for a RXLR effector.

    Directory of Open Access Journals (Sweden)

    Klaas Bouwmeester

    2011-03-01

    Full Text Available In plants, an active defense against biotrophic pathogens is dependent on a functional continuum between the cell wall (CW and the plasma membrane (PM. It is thus anticipated that proteins maintaining this continuum also function in defense. The legume-like lectin receptor kinase LecRK-I.9 is a putative mediator of CW-PM adhesions in Arabidopsis and is known to bind in vitro to the Phytophthora infestans RXLR-dEER effector IPI-O via a RGD cell attachment motif present in IPI-O. Here we show that LecRK-I.9 is associated with the plasma membrane, and that two T-DNA insertions lines deficient in LecRK-I.9 (lecrk-I.9 have a 'gain-of-susceptibility' phenotype specifically towards the oomycete Phytophthora brassicae. Accordingly, overexpression of LecRK-I.9 leads to enhanced resistance to P. brassicae. A similar 'gain-of-susceptibility' phenotype was observed in transgenic Arabidopsis lines expressing ipiO (35S-ipiO1. This phenocopy behavior was also observed with respect to other defense-related functions; lecrk-I.9 and 35S-ipiO1 were both disturbed in pathogen- and MAMP-triggered callose deposition. By site-directed mutagenesis, we demonstrated that the RGD cell attachment motif in IPI-O is not only essential for disrupting the CW-PM adhesions, but also for disease suppression. These results suggest that destabilizing the CW-PM continuum is one of the tactics used by Phytophthora to promote infection. As countermeasure the host may want to strengthen CW-PM adhesions and the novel Phytophthora resistance component LecRK-I.9 seems to function in this process.

  20. The lectin receptor kinase LecRK-I.9 is a novel Phytophthora resistance component and a potential host target for a RXLR effector.

    Science.gov (United States)

    Bouwmeester, Klaas; de Sain, Mara; Weide, Rob; Gouget, Anne; Klamer, Sofieke; Canut, Herve; Govers, Francine

    2011-03-01

    In plants, an active defense against biotrophic pathogens is dependent on a functional continuum between the cell wall (CW) and the plasma membrane (PM). It is thus anticipated that proteins maintaining this continuum also function in defense. The legume-like lectin receptor kinase LecRK-I.9 is a putative mediator of CW-PM adhesions in Arabidopsis and is known to bind in vitro to the Phytophthora infestans RXLR-dEER effector IPI-O via a RGD cell attachment motif present in IPI-O. Here we show that LecRK-I.9 is associated with the plasma membrane, and that two T-DNA insertions lines deficient in LecRK-I.9 (lecrk-I.9) have a 'gain-of-susceptibility' phenotype specifically towards the oomycete Phytophthora brassicae. Accordingly, overexpression of LecRK-I.9 leads to enhanced resistance to P. brassicae. A similar 'gain-of-susceptibility' phenotype was observed in transgenic Arabidopsis lines expressing ipiO (35S-ipiO1). This phenocopy behavior was also observed with respect to other defense-related functions; lecrk-I.9 and 35S-ipiO1 were both disturbed in pathogen- and MAMP-triggered callose deposition. By site-directed mutagenesis, we demonstrated that the RGD cell attachment motif in IPI-O is not only essential for disrupting the CW-PM adhesions, but also for disease suppression. These results suggest that destabilizing the CW-PM continuum is one of the tactics used by Phytophthora to promote infection. As countermeasure the host may want to strengthen CW-PM adhesions and the novel Phytophthora resistance component LecRK-I.9 seems to function in this process.

  1. Genomic characterization of a South American Phytophthora hybrid mandates reassessment of the geographic origins of Phytophthora infestans

    DEFF Research Database (Denmark)

    Martin, Michael David; Garrett Vieira, Filipe Jorge; Ho, Simon Y. W.

    2016-01-01

    of P. infestans and the hybrid species P. andina, a close relative known only from the Andean highlands. Previous studies have suggested that the nuclear DNA lineage behind the initial outbreaks in Europe in 1845 is now extinct. Analysis of P. andina's phased haplotypes recovered eight haploid genome...

  2. Biological characteristics of strain F603 of Epicoccom sp.,an antagonistic fungus for controlling Phytophthora infestans

    Institute of Scientific and Technical Information of China (English)

    LIU Xiaoyun; HU Tongle; CAO Keqiang

    2007-01-01

    Factors influencing vegetative growth and spore germination of strain F603 of Epicoccom sp.,an antagonistic fungus for Phytophthora infestans (Mont) de Bary,were studied.Among the different growth media tested,Rye agar was the best medium for its vegetative growth.The range of temperature and pH value for mycelial growth was 5-35℃ and 2-12,respectively,with the optimum 25℃ and 6-9,respectively.The fungus grew better in Czapek medium with maltose and dextrose as carbon sources and peptone,KNO3,and NaNO3 as nitrogen sources.The range of temperature for spore germination of strain F603 was 5-35℃,the optimum was 20℃.The range of temperature for sporulation was 10-30℃,and the optimum was 15-18℃.

  3. The behaviour of certain potato varieties and lines towards the attack of the Phytophthora infestans (Mont de Bary fungus

    Directory of Open Access Journals (Sweden)

    Daniela POPA

    2008-05-01

    Full Text Available This paper presents the behaviour of some potato varieties and lines towards the attack of the Phytophthora infestans (Mont de Bary fungus under the field conditions of the Potato Research and Development Station, Targu-Secuiesc. During the observed period (2001-2003 the appearance of new forms of attack was registered, for example the attack on the stem, on the leaf petioles, as well as a greater number of infected tubers. The greatest number of blighted stems belonged to the varieties Sante and Ostara, and the smallest one was registered in the case of the variety Lady Roseta, followed by Desiree and Nemere. The results prove that there is a direct relationship between the frequency of the attack on the stems and that of the blighted tubers in the case of every variety, except for the varieties Lady Roseta and Nemere at which the smallest number of infected tubers was registered.

  4. A proteomics study of in vitro cyst germination and appressoria formation in ¤Phytophthora infestans¤

    DEFF Research Database (Denmark)

    Ebstrup, T.; Saalbach, G.; Egsgaard, H.

    2005-01-01

    A proteomics study using two-dimensional gel electrophoresis (2-DE) and mass spectrometry was performed on Phytophthora infestans. Proteins from cysts, germinated cysts and appressoria grown in vitro were isolated and separated by 2-DE. Statistical quantitative analysis of the protein spots from...... five independent experiments of each developmental stage revealed significant up-regulation of ten spots on gels from germinated cysts compared to cysts. Five spots were significantly up-regulated on gels from appressoria compared to germinated cysts and one of these up-regulated spots...... was not detectable on gels from cysts. In addition, one spot was significantly down-regulated and another spot not detectable on the gels from appressoria. The corresponding proteins to 13 of these spots were identified with high confidence using tandem mass spectrometry and database searches. The functions...

  5. Transgene-induced silencing of the zoosporogenesis-specific NIFC gene cluster of Phytophthora infestans involves chromatin alterations.

    Science.gov (United States)

    Judelson, Howard S; Tani, Shuji

    2007-07-01

    Clustered within the genome of the oomycete phytopathogen Phytophthora infestans are four genes encoding spore-specific nuclear LIM interactor-interacting factors (NIF proteins, a type of transcriptional regulator) that are moderately conserved in DNA sequence. NIFC1, NIFC2, and NIFC3 are zoosporogenesis-induced and grouped within 4 kb, and 20 kb away resides a sporulation-induced form, NIFS. To test the function of the NIFC family, plasmids expressing full-length hairpin constructs of NIFC1 or NIFC2 were stably transformed into P. infestans. This triggered silencing of the cognate gene in about one-third of transformants, and all three NIFC genes were usually cosilenced. However, NIFS escaped silencing despite its high sequence similarity to the NIFC genes. Silencing of the three NIFC genes impaired zoospore cyst germination by 60% but did not affect other aspects of the life cycle. Silencing was transcriptional based on nuclear run-on assays and associated with tighter chromatin packing based on nuclease accessibility experiments. The chromatin alterations extended a few hundred nucleotides beyond the boundaries of the transcribed region of the NIFC cluster and were not associated with increased DNA methylation. A plasmid expressing a short hairpin RNA having sequence similarity only to NIFC1 silenced both that gene and an adjacent member of the gene cluster, likely due to the expansion of a heterochromatic domain from the targeted locus. These data help illuminate the mechanism of silencing in Phytophthora and suggest that caution should be used when interpreting silencing experiments involving closely spaced genes.

  6. NBS Proifling Identiifes Potential Novel Locus from Solanum demissum That Confers Broad-Spectrum Resistance to Phytophthora infestans

    Institute of Scientific and Technical Information of China (English)

    ZHANG Kun; XU Jian-fei; DUAN Shao-guang; PANG Wan-fu; BIAN Chun-song; LIU Jie; JIN Li-ping

    2014-01-01

    Potato late blight, caused by the oomycete pathogen Phytophthora infestans, is the most serious disease of potato worldwide. The adoption of varieties with resistance genes, especially broad-spectrum resistance genes, is the most efifcient approach to control late blight. Solanum demissum is a well-known wild potato species from which 11 race-speciifc resistance genes have been identiifed, however, no broad-spectrum resistance genes like RB have been reported in this species. Here, we report a novel reisistance locus from S. demissum that potentially confer broad-spectrum resistance to late blight. A small segregating population of S. demissum were assessed for resistance to aggressive P. infestans isolates (race 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11). This coupled with nucleotide binding site (NBS) proifling analyses, led to the identiifcation of three fragments that linked to the potential candidate resistance gene(s). Cloning and sequence analysis of these fragments suggested that the identiifed resistance gene locus is located in the region containing R2 resistance gene at chromosome 4. Based on the sequences of the cloned fragments, a co-segregating sequence characterized ampliifed region (SCAR) marker, RDSP, was developed. The newly identiifed marker RDSP will be useful for marker assisted breeding and further cloning of this potential resistance gene locus.

  7. The Loricrin-Like Protein (LLP) of Phytophthora infestans Is Required for Oospore Formation and Plant Infection

    Science.gov (United States)

    Guo, Ting; Wang, Xiao-Wen; Shan, Kun; Sun, Wenxian; Guo, Li-Yun

    2017-01-01

    Loricrin-like protein (LLP) is characterized by a high content of glycine residues and is a major component of plant cell wall. Here, we identified a Phytophthora infestans ortholog of plant LLP, named PiLLP. In P. infestans, PiLLP is strongly expressed in asexual and sexual developmental stages, including in sporangia, zoospores and germinating cysts, and during oospore formation, as well as in the early stages of infection and during hydrogen peroxide stress. Compared with the wild type, the PiLLP-silenced transformants were defective in oospore formation, had slower colony expansion rates, produced less sporangia with lower germination and zoospore-release rates, and were more sensitive to hydrogen peroxide. Moreover, Nile red staining, and PiLLP-red fluorescent protein fusions indicated that PiLLP is involved in oogonia formation. The silenced transformants also had severely diminished virulence levels that could be partially restored with diphenyleneiodium treatments. The analysis of catalase activity showed a decrease of catalase activity in silenced transformants. Thus, PiLLP is important for sexual and asexual reproduction, and is required for oxidative stress tolerance and plant infection. PMID:28232841

  8. Age-related Resistance and the Defense Signaling Pathway of Ph-3 Gene Against Phytophthora infestans in Tomatoes

    Directory of Open Access Journals (Sweden)

    Sayed Rashad Ali Shah

    2015-09-01

    Full Text Available Resistance (R genes against plant pathogens often have age-related resistance (ARR effects. However, the mechanism involved in this phenomenon remains unknown. In this paper, Solanum lycopersicum ‘CLN2037B’ and S. pimpinellifolium ‘L3708’ harboring the Ph-3 gene, as well as S. habrochaites ‘LA2099’, ‘LA1777’ and ‘LA1033’ harboring quantitative trait loci (QTLs, were tested to investigate age-related resistance against late blight (LB; caused by Phytophthora infestans in the three-leaf stage of the plants. The results demonstrated that the QTL-related LB resistance showed the same age-related resistance as the Ph-3-mediated resistance at the six- and nine-leaf stages compared with the three-leaf stage. This indicated that there is a common defense mechanism in tomatoes against P. infestans via ARR. In addition, we combined ethylene (ET, salicylic acid (SA and jasmonic acid (JA mutants with virus-induced gene silencing (VIGS to study the Ph-3-dependent resistance signaling pathway. The results showed that ethylene and salicylic acid, but not jasmonic acid, are involved in the LB resistance mediated by the Ph-3 gene.

  9. Sequence diversity in the large subunit of RNA polymerase I contributes to Mefenoxam insensitivity in Phytophthora infestans.

    Science.gov (United States)

    Randall, Eva; Young, Vanessa; Sierotzki, Helge; Scalliet, Gabriel; Birch, Paul R J; Cooke, David E L; Csukai, Michael; Whisson, Stephen C

    2014-09-01

    Phenylamide fungicides have been widely used for the control of oomycete-incited plant diseases for over 30 years. Insensitivity to this chemical class of fungicide was recorded early in its usage history, but the precise protein(s) conditioning insensitivity has proven difficult to determine. To determine the genetic basis of insensitivity and to inform strategies for the cloning of the gene(s) responsible, genetic crosses were established between Mefenoxam sensitive and intermediate insensitive isolates of Phytophthora infestans, the potato late blight pathogen. F1 progeny showed the expected semi-dominant phenotypes for Mefenoxam insensitivity and suggested the involvement of multiple loci, complicating the positional cloning of the gene(s) conditioning insensitivity to Mefenoxam. Instead, a candidate gene strategy was used, based on previous observations that the primary effect of phenylamide compounds is to inhibit ribosomal RNA synthesis. The subunits of RNA polymerase I (RNApolI) were sequenced from sensitive and insensitive isolates and F1 progeny. Single nucleotide polymorphisms (SNPs) specific to insensitive field isolates were identified in the gene encoding the large subunit of RNApolI. In a survey of field isolates, SNP T1145A (Y382F) showed an 86% association with Mefenoxam insensitivity. Isolates not showing this association belonged predominantly to one P. infestans genotype. The transfer of the 'insensitive' allele of RPA190 to a sensitive isolate yielded transgenic lines that were insensitive to Mefenoxam. These results demonstrate that sequence variation in RPA190 contributes to insensitivity to Mefenoxam in P. infestans.

  10. NiaA, the structural nitrate reductase gene of Phytophthora infestans: isolation, characterization and expression analysis in Aspergillus nidulans.

    Science.gov (United States)

    Pieterse, C M; van't Klooster, J; van den Berg-Velthuis, G C; Govers, F

    1995-03-01

    The nitrate reductase (NR) gene niaA of the oomycete Phytophthora infestans was selected from a gene library by heterologous hybridization. NiaA occurs as a single-copy gene ant its expression is regulated by the nitrogen source. The nucleotide sequence of niaA was determined and comparison of the deduced amino-acid sequence of 902 residues with NRs of higher fungi and plants revealed a significant homology, particularly within the three cofactor-binding domains for molybdenum, heme and FAD. The P. infestans niaA gene was used as a model gene to test whether oomycete genes are functional in the ascomycete Aspergillus nidulans, a fungus which is highly accessible for molecular genetic studies. The complete niaA gene was stably integrated into the genome of a nia- deletion mutant of A. nidulans. However, transformants containing one or more copies of the niaA gene were not able to complement the nia- mutant. This suggests that there is no functional expression of the introduced niaA gene in A. nidulans. In addition, the activity of two other oomycete gene promoters was analyzed in a transient expression assay. Plasmids containing chimaeric genes with the promoter of the P. infestans ubiquitin gene ubi3R, or the Bremia lactucae ham34 gene, fused to the coding sequence of the Escherichia coli beta-glucuronidase (GUS) reporter gene, were transferred to A. nidulans protoplasts. No significant GUS activity was detectable indicating that the ubi3R and ham34 promoters are not active in A. nidulans. Apparently, the regulatory sequences which are sufficient for gene activation in oomycetes are not functional in the ascomycete A. nidulans.

  11. 致病疫霉拮抗真菌研究进展%Advances of antagonistic fungi against Phytophthora infestans

    Institute of Scientific and Technical Information of China (English)

    蒋继志; 郭俊亭; 李丽艳

    2012-01-01

    Phytophthora infestans (Mont. ) de Bary causes late blight of potato and tomato, and is the first important factor limiting sustainability for potato and tomato production all over the world. Current resistant varieties, agricultural cultivations, and chemical fungicides could not completely and effectively control the late blight since P. Infestans has evident physiological differentiation and quick hereditary vari ation. To explore antagonistic fungi and develop safe and high effective microbial pesticide against P. In festans is one of the main study fields at present. In order to carry out biological control of potato and tomato late blight, the progress on antagonistic fungi to P. Infestans in recent years were reviewed, and some problems existing in this field and research highlight were pointed out.%致病疫霉主要引起马铃薯和番茄的晚疫病,是严重制约马铃薯和番茄生产可持续发展的首要因素.生产中可利用的措施主要有选育和利用抗病品种、农业栽培措施和化学农药,但因病菌生理分化明显、遗传变异迅速,现有措施难以完全有效控制该病,发掘致病疲霉拮抗微生物并研发安全高效的微生物农药是当前的主要研究方向之一.综述了近年来对于致病疫霉拮抗真菌的研究进展,并指出了在该领域中存在的一些问题和今后的研究重点,以期对马铃薯晚疫病的生物防治发挥推进作用.

  12. Activation of Zoosporogenesis-Specific Genes in Phytophthora infestans Involves a 7-Nucleotide Promoter Motif and Cold-Induced Membrane Rigidity

    OpenAIRE

    Tani, Shuji; Judelson, Howard

    2006-01-01

    Infections of plants by the oomycete Phytophthora infestans typically result from zoospores, which develop from sporangia at cold temperatures. To help understand the relevant cold-induced signaling pathway, factors regulating the transcription of the zoosporogenesis-specific NIF (nuclear LIM-interactor-interacting factor) gene family were examined. Sequences required for inducing PinifC3 were identified by analyzing truncated and mutated promoters using the β-glucuronidase reporter in stable...

  13. Efecto de algunos aceites esenciales sobre el crecimiento de Phytophthora infestans (Mont. de Bary en condiciones de laboratorio

    Directory of Open Access Journals (Sweden)

    Carrillo Yazmid Adriana

    2010-08-01

    Full Text Available Entre los factores más limitantes del cultivo de papa se encuentra
    Phytophthora infestans, agente causal de la llamada “gota”.
    El control químico de esta enfermedad representa entre el 7 y
    el 10% de los costos totales del cultivo, y tiene un alto impacto
    ambiental por la contaminación que ocasiona. La búsqueda
    y aplicación de prácticas alternativas para el control de este
    patógeno es importante para disminuir tanto la utilización de
    fungicidas como los costos de producción del cultivo. Numerosos
    estudios realizados in vitro demuestran que algunos aceites
    esenciales tienen propiedades fungicidas y fungistáticas sobre
    diferentes patógenos. Por ello, el objetivo del presente estudio
    consistio en la evaluacion de ocho aceites esenciales extraidos
    de algunas especies aromaticas de la familia Lamiaceae sobre
    el crecimiento de P. infestans en condiciones de laboratorio. Se
    evaluaron diferentes metodologías de aplicación de los productos
    en estudio, encontrándose que las mas apropiadas son aquellas
    en que el aceite ejerce un efecto volátil. Los aceites esenciales
    fueron Origanum vulgare, Mentha piperita, Salvia officinalis,
    Ocimum basilicum, Rosmarinus officinalis, Origanum majorana,
    Thymus vulgaris y Pogostemon cablin se evaluaron en
    su fase volatil, a traves de su efecto sobre dos aislamientos
    de P. infestans (A13 y A15. Los aceites que mostraron efecto
    inhibitorio sobre el crecimiento de P. infestans fueron los de T.
    vulgaris y M. piperita, los cuales redujeron el crecimiento del
    hongo en 92,1 y 89,9%, respectivamente; y por ello pueden ser
    considerados promisorios para ser evaluados en campo.

  14. Establishment of the straightforward electro-transformation system for Phytophthora infestans and its comparison with the improved PEG/CaCl₂ transformation.

    Science.gov (United States)

    Dong, Lei; Zhu, Xiangyuan; Cui, Haichen; Ojika, Makoto; Wang, Ruigang; Liu, Huirong

    2015-05-01

    Phytophthora infestans is the most devastating pathogen of potato. For the biology study of P. infestans at the molecular level, one of the difficulties is the technique for the genetic transformation. In this study, the straightforward electro-transformation system was established for P. infestans with a green fluorescent protein expression vector and compared with the improved PEG/CaCl2 mediated protoplast transformation system. The results showed that the straightforward electro-transformation could work in P. infestans and 32 positive transformants were obtained per about 1.10×10(6) zoospores. The transformants per μg of vector DNA were 1.08. The transformation efficiency of the straightforward electro-transformation was approximately 2 times higher than that of the improved PEG/CaCl2 mediated protoplast transformation (17 positive transformants per about 1.05×10(6) protoplasts, 0.58 transformants per μg of vector DNA) according to the reported procedures. Furthermore, compared with the improved PEG/CaCl2 transformation, the straightforward electroporation is simpler and requires less starting materials and operating time from collecting material to obtaining the resistant transformants. Our work will lay a foundation for the biology study of P. infestans in the future.

  15. Spatial Analysis of Phytophthora infestans Genotypes and Late Blight Severity on Tomato and Potato in the Del Fuerte Valley Using Geostatistics and Geographic Information Systems.

    Science.gov (United States)

    Jaime-Garcia, R; Orum, T V; Felix-Gastelum, R; Trinidad-Correa, R; Vanetten, H D; Nelson, M R

    2001-12-01

    ABSTRACT Genetic structure of Phytophthora infestans, the causal agent of potato and tomato late blight, was analyzed spatially in a mixed potato and tomato production area in the Del Fuerte Valley, Sinaloa, Mexico. Isolates of P. infestans were characterized by mating type, allozyme analysis at the glucose-6-phosphate isomerase and peptidase loci, restriction fragment length polymorphism with probe RG57, metalaxyl sensitivity, and aggressiveness to tomato and potato. Spatial patterns of P. infestans genotypes were analyzed by geographical information systems and geo-statistics during the seasons of 1994-95, 1995-96, and 1996-97. Spatial analysis of the genetic structure of P. infestans indicates that geographic substructuring of this pathogen occurs in this area. Maps displaying the probabilities of occurrence of mating types and genotypes of P. infestans, and of disease severity at a regional scale, were presented. Some genotypes that exhibited differences in epidemiologically important features such as metalaxyl sensitivity and aggressiveness to tomato and potato had a restricted spread and were localized in isolated areas. Analysis of late blight severity showed recurring patterns, such as the earliest onset of the disease in the area where both potato and tomato were growing, strengthening the hypothesis that infected potato tubers are the main source of primary inoculum. The information that geostatistical analysis provides might help improve management programs for late blight in the Del Fuerte Valley.

  16. Impact of new populations of Phytophthora infestans on integrated late blight management

    NARCIS (Netherlands)

    Flier, W.G.; Kessel, G.J.T.; Bosch, van den G.B.M.; Turkensteen, L.J.

    2002-01-01

    A recent migration of a variable population of P. infestans has largely displaced the clonal A1 population in Western Europe. Sexual reproduction in European late blight populations is now possible and has been reported. The increased levels of aggressiveness form an important epidemiological featur

  17. Screening of Chinese herbs for the fungitoxicity against Phytophthora infestans%对马铃薯晚疫病菌(Phytophthora infestans)有杀菌毒性的中草药的筛选

    Institute of Scientific and Technical Information of China (English)

    王树桐; 王晓燕; 刘均玲; 曹克强

    2001-01-01

    Plant extracts of 88 species from 44 families of plants were diluted to 500 times, and mixed with sporangia suspension of P. infestans, then the sporangia suspensions were put into 10℃ incubator for 3hours. The result is as follows: 31 species were completely inhibitory, 46 species were strongly or moderately inhibitory and 11 were little inhibitory to sporangia indirect germination of P. infestans. And among 83species in 43 families of plants tested, mother extracts from 32 species were completely inhibitory, 24 were strongly inhibitory and 27 were weakly or even no inhibitory to mycelial growth of P. infestans at 200 times.There are also 19 mother extracts were not only completely inhibitory to germination of sporangia but also completely inhibitory to mycelial growth of P. infestans.%将来源于44科的88种中草药等植物材料的提取物稀释500倍后,与马铃薯晚疫病菌(Phytophthora infestans)的孢子囊悬浮液混合.有31种材料的提取物在该浓度下表现了对马铃薯晚疫病菌的游动孢子囊间接萌发的完全抑制作用,有46种提取物也表现了不同程度的抑制作用,另有11种提取物在该浓度下没有表现抑制作用.在抑制菌丝生长作用的试验中,植物提取物用黑麦培养基稀释200倍,然后倒皿,在8.5 cm直径的培养皿中央放一马铃薯晚疫病菌菌片,16℃下培养,15 d后测量菌落直径大小.结果表明,在供试的83种提取物中,在稀释200倍浓度下,有32种提取物表现了对菌丝生长的完全抑制作用,24种表现了比较强的抑制作用,而有27种提取物没有表现对菌丝生长的抑制作用,甚至还表现了对菌丝生长的促进作用.同时,还有19种提取物在抑制孢子囊萌发和抑制菌丝生长两项测试中均表现出完全的抑制作用.

  18. Gene duplication and fragment recombination drive functional diversification of a superfamily of cytoplasmic effectors in Phytophthora sojae.

    Science.gov (United States)

    Shen, Danyu; Liu, Tingli; Ye, Wenwu; Liu, Li; Liu, Peihan; Wu, Yuren; Wang, Yuanchao; Dou, Daolong

    2013-01-01

    Phytophthora and other oomycetes secrete a large number of putative host cytoplasmic effectors with conserved FLAK motifs following signal peptides, termed crinkling and necrosis inducing proteins (CRN), or Crinkler. Here, we first investigated the evolutionary patterns and mechanisms of CRN effectors in Phytophthora sojae and compared them to two other Phytophthora species. The genes encoding CRN effectors could be divided into 45 orthologous gene groups (OGG), and most OGGs unequally distributed in the three species, in which each underwent large number of gene gains or losses, indicating that the CRN genes expanded after species evolution in Phytophthora and evolved through pathoadaptation. The 134 expanded genes in P. sojae encoded family proteins including 82 functional genes and expressed at higher levels while the other 68 genes encoding orphan proteins were less expressed and contained 50 pseudogenes. Furthermore, we demonstrated that most expanded genes underwent gene duplication or/and fragment recombination. Three different mechanisms that drove gene duplication or recombination were identified. Finally, the expanded CRN effectors exhibited varying pathogenic functions, including induction of programmed cell death (PCD) and suppression of PCD through PAMP-triggered immunity or/and effector-triggered immunity. Overall, these results suggest that gene duplication and fragment recombination may be two mechanisms that drive the expansion and neofunctionalization of the CRN family in P. sojae, which aids in understanding the roles of CRN effectors within each oomycete pathogen.

  19. Gene duplication and fragment recombination drive functional diversification of a superfamily of cytoplasmic effectors in Phytophthora sojae.

    Directory of Open Access Journals (Sweden)

    Danyu Shen

    Full Text Available Phytophthora and other oomycetes secrete a large number of putative host cytoplasmic effectors with conserved FLAK motifs following signal peptides, termed crinkling and necrosis inducing proteins (CRN, or Crinkler. Here, we first investigated the evolutionary patterns and mechanisms of CRN effectors in Phytophthora sojae and compared them to two other Phytophthora species. The genes encoding CRN effectors could be divided into 45 orthologous gene groups (OGG, and most OGGs unequally distributed in the three species, in which each underwent large number of gene gains or losses, indicating that the CRN genes expanded after species evolution in Phytophthora and evolved through pathoadaptation. The 134 expanded genes in P. sojae encoded family proteins including 82 functional genes and expressed at higher levels while the other 68 genes encoding orphan proteins were less expressed and contained 50 pseudogenes. Furthermore, we demonstrated that most expanded genes underwent gene duplication or/and fragment recombination. Three different mechanisms that drove gene duplication or recombination were identified. Finally, the expanded CRN effectors exhibited varying pathogenic functions, including induction of programmed cell death (PCD and suppression of PCD through PAMP-triggered immunity or/and effector-triggered immunity. Overall, these results suggest that gene duplication and fragment recombination may be two mechanisms that drive the expansion and neofunctionalization of the CRN family in P. sojae, which aids in understanding the roles of CRN effectors within each oomycete pathogen.

  20. General research methods on pathogen of potato late blight (Phytophthora infestans)%马铃薯晚疫病菌的常规研究方法

    Institute of Scientific and Technical Information of China (English)

    朱杰华; 张志铭; 杨志辉

    2001-01-01

    马铃薯晚疫病菌很难分离培养并得到纯菌株,本文根据作者近8年的工作经验总结出了马铃薯晚疫病菌的一般研究方法,主要内容包括马铃薯晚疫病菌的症状识别,马铃薯晚疫病标样的采集方法,马铃薯晚疫病菌的分离纯化方法,马铃薯晚疫病菌的形态鉴定,马铃薯品种对晚疫病的抗病性评价方法等.%It's known that Phytophthora infestans is very difficult to be isolated and purified. According to the working experience in the past 8 years, the general research methods of potato late blight were summerized in this paper, which includes the method of sample collection of Phytophthora infestans, the methods of isolation and purification of P. infestans, evaluation of late blight resistance in potato germplasm.

  1. GK4, a G-protein-coupled receptor with a phosphatidylinositol phosphate kinase domain in Phytophthora infestans, is involved in sporangia development and virulence.

    Science.gov (United States)

    Hua, Chenlei; Meijer, Harold J G; de Keijzer, Jeroen; Zhao, Wei; Wang, Yuanchao; Govers, Francine

    2013-04-01

    For dispersal and host infection plant pathogens largely depend on asexual spores. Pathogenesis and sporulation are complex processes that are governed by cellular signalling networks including G-protein and phospholipid signalling. Oomycetes possess a family of novel proteins called GPCR-PIPKs (GKs) that are composed of a seven-transmembrane spanning (7-TM) domain fused to a phosphatidylinositol phosphate kinase (PIPK) domain. Based on this domain structure GKs are anticipated to link G-protein and phospholipid signal pathways; however, their functions are currently unknown. Expression analyses of the 12 GK genes in Phytophthora infestans and their orthologues in Phytophthora sojae, revealed differential expression during asexual development. PiGK1 and PiGK4 were fused to monomeric red fluorescent protein (mRFP) and ectopically expressed in P. infestans. In growing hyphae different subcellular distribution patterns were observed indicating that these two GKs act independently during development. We focused on the functional analyses of PiGK4. Its localization suggested involvement in cell differentiation and elongation and its 7-TM domain showed a canonical GPCR membrane topology. Silencing of GK4 and overexpression of full-length and truncated constructs in P. infestans revealed that PiGK4 is not only involved in spore germination and hyphal elongation but also in sporangia cleavage and infection.

  2. Doseringsverlaging op basis van loof- en knolresistentie tegen Phytophthora infestans in aardappel

    NARCIS (Netherlands)

    Spits, H.G.

    2007-01-01

    Een mogelijkheid om het middelengebruik omlaag te krijgen is een bestrijdingsstrategie te ontwikkelen waarbij de gevoeligheid van het ras gebruikt wordt bij de beheersing van de aardappelziekte. Bij zo’n strategie zou een ras dat weinig gevoelig is voor Phytophthora met een lagere dosering net zo go

  3. Analysis of the tomato leaf transcriptome during successive hemibiotrophic stages of a compatible interaction with the oomycete pathogen Phytophthora infestans.

    Science.gov (United States)

    Zuluaga, Andrea P; Vega-Arreguín, Julio C; Fei, Zhangjun; Matas, Antonio J; Patev, Sean; Fry, William E; Rose, Jocelyn K C

    2016-01-01

    The infection of plants by hemibiotrophic pathogens involves a complex and highly regulated transition from an initial biotrophic, asymptomatic stage to a later necrotrophic state, characterized by cell death. Little is known about how this transition is regulated, and there are conflicting views regarding the significance of the plant hormones jasmonic acid (JA) and salicylic acid (SA) in the different phases of infection. To provide a broad view of the hemibiotrophic infection process from the plant perspective, we surveyed the transcriptome of tomato (Solanum lycopersicum) during a compatible interaction with the hemibiotrophic oomycete Phytophthora infestans during three infection stages: biotrophic, the transition from biotrophy to necrotrophy, and the necrotrophic phase. Nearly 10 000 genes corresponding to proteins in approximately 400 biochemical pathways showed differential transcript abundance during the three infection stages, revealing a major reorganization of plant metabolism, including major changes in source-sink relations, as well as secondary metabolites. In addition, more than 100 putative resistance genes and pattern recognition receptor genes were induced, and both JA and SA levels and associated signalling pathways showed dynamic changes during the infection time course. The biotrophic phase was characterized by the induction of many defence systems, which were either insufficient, evaded or suppressed by the pathogen.

  4. To be or not to be solitary: Phytophthora infestans' dilemma for optimizing its reproductive fitness in multiple infections.

    Directory of Open Access Journals (Sweden)

    Julie A J Clément

    Full Text Available The success of parasitic life lies in an optimal exploitation of the host to satisfy key functions directly involved in reproductive fitness. Resource availability generally decreases over time with host mortality, but also during multiple infections, where different strains of parasite share host resources. During multiple infections, the number of parasite strains and their genetic relatedness are known to influence their reproductive rates. Using infections of the potato plant Solanum tuberosum with the parasite Phytophthora infestans, we set up an experimental design to separate dose effects (double- vs. single-site infections from genetic relatedness (different vs. identical genotypes on the reproductive fitness of competing parasite genotypes. We showed the existence of two basic response patterns--increase or decrease in reproductive fitness in multiple infections- depending on the parasite genotype. In all cases, the intensity of the response of any genotype depended on the genotype of the competing strain. This diversity of responses to multiple infections is probably maintained by the fluctuating frequencies of multiple infections in nature, arising from variations in disease pressure over the course of an epidemic and between successive epidemics. It allows a rapid response of parasitic populations to changing environments, which are particularly intense in agricultural systems.

  5. Four potato (Solanum tuberosum) ABCG transporters and their expression in response to abiotic factors and Phytophthora infestans infection.

    Science.gov (United States)

    Ruocco, Michelina; Ambrosino, Patrizia; Lanzuise, Stefania; Woo, Sheridan Lois; Lorito, Matteo; Scala, Felice

    2011-12-15

    Pleiotropic drug resistant (PDR/ABCG) genes are involved in plant response to biotic and abiotic stresses. In this work, we cloned, from Solanum tuberosum, four PDR/ABCG transporter genes named StPDR1, StPDR2, StPDR3 and StPDR4, which were differentially expressed in plant tissues and cell cultures. A number of different chemically unrelated compounds were found to regulate the transcript levels of the four genes in cultured cells. In particular, StPDR2 was highly up-regulated in the presence of Botrytis cinerea cell walls, NaCl, 2,4-dichlorophenol, sclareol and α-solanin and biological compounds. The expression of the genes was also investigated by real time RT-PCR during infection by Phytophthora infestans. StPDR1 and StPDR2 were up-regulated about 13- and 37-fold at 48 h post-infection (hpi), StPDR3 was expressed (4-5-fold) at 24 and 48 hpi and then rapidly decreased, while StPDR4 RNA accumulation was stimulated (about 4-fold) at 12 and 24 hpi, decreased at 48 hpi and increased again at 96 hpi. We discuss the role of StPDR1-4 genes in response to pathogens and abiotic stresses.

  6. Local adaptation to temperature in populations and clonal lineages of the Irish potato famine pathogen Phytophthora infestans.

    Science.gov (United States)

    Mariette, Nicolas; Androdias, Annabelle; Mabon, Romain; Corbière, Roselyne; Marquer, Bruno; Montarry, Josselin; Andrivon, Didier

    2016-09-01

    Environmental factors such as temperature strongly impact microbial communities. In the current context of global warming, it is therefore crucial to understand the effects of these factors on human, animal, or plant pathogens. Here, we used a common-garden experiment to analyze the thermal responses of three life-history traits (latent period, lesion growth, spore number) in isolates of the potato late blight pathogen Phytophthora infestans from different climatic zones. We also used a fitness index (FI) aggregating these traits into a single parameter. The experiments revealed patterns of local adaptation to temperature for several traits and for the FI, both between populations and within clonal lineages. Local adaptation to temperature could result from selection for increased survival between epidemics, when isolates are exposed to more extreme climatic conditions than during epidemics. We also showed different thermal responses among two clonal lineages sympatric in western Europe, with lower performances of lineage 13_A2 compared to 6_A1, especially at low temperatures. These data therefore stress the importance of thermal adaptation in a widespread, invasive pathogen, where adaptation is usually considered almost exclusively with respect to host plants. This must now be taken into account to explain, and possibly predict, the global distribution of specific lineages and their epidemic potential.

  7. Rpi-blb2-Mediated Hypersensitive Cell Death Caused by Phytophthora infestans AVRblb2 Requires SGT1, but not EDS1, NDR1, Salicylic Acid-, Jasmonic Acid-, or Ethylene-Mediated Signaling

    Directory of Open Access Journals (Sweden)

    Sang-Keun Oh

    2014-09-01

    Full Text Available Potato Rpi-blb2 encodes a protein with a coiled-coil-nucleotide binding site and leucine-rich repeat (CC-NBS-LRR motif that recognizes the Phytophthora infestans AVRblb2 effector and triggers hypersensitive cell death (HCD. To better understand the components required for Rpi-blb2-mediated HCD in plants, we used virus-induced gene silencing to repress candidate genes in Rpi-blb2-transgenic Nicotiana benthamiana plants and assayed the plants for AVRblb2 effector. Rpi-blb2 triggers HCD through NbSGT1-mediated pathways, but not NbEDS1- or NbNDR1-mediated pathways. In addition, the role of salicylic acid (SA, jasmonic acid (JA, and ethylene (ET in Rpi-blb2-mediated HCD were analyzed by monitoring of the responses of NbICS1-, NbCOI1-, or NbEIN2-silenced or Rpi-blb2::NahG-transgenic plants. Rpi-blb2-mediated HCD in response to AVRblb2 was not associated with SA accumulation. Thus, SA affects Rpi-blb2-mediated resistance against P. infestans, but not Rpi-blb2-mediated HCD in response to AVRblb2. Additionally, JA and ET signaling were not required for Rpi-blb2-mediated HCD in N. benthamiana. Taken together, these findings suggest that NbSGT1 is a unique positive regulator of Rpi-blb2-mediated HCD in response to AVRblb2, but EDS1, NDR1, SA, JA, and ET are not required.

  8. Rpi-blb2-Mediated Hypersensitive Cell Death Caused by Phytophthora infestans AVRblb2 Requires SGT1, but not EDS1, NDR1, Salicylic Acid-, Jasmonic Acid-, or Ethylene-Mediated Signaling.

    Science.gov (United States)

    Oh, Sang-Keun; Kwon, Suk-Yoon; Choi, Doil

    2014-09-01

    Potato Rpi-blb2 encodes a protein with a coiled-coil-nucleotide binding site and leucine-rich repeat (CC-NBS-LRR) motif that recognizes the Phytophthora infestans AVRblb2 effector and triggers hypersensitive cell death (HCD). To better understand the components required for Rpi-blb2-mediated HCD in plants, we used virus-induced gene silencing to repress candidate genes in Rpi-blb2-transgenic Nicotiana benthamiana plants and assayed the plants for AVRblb2 effector. Rpi-blb2 triggers HCD through NbSGT1-mediated pathways, but not NbEDS1- or NbNDR1-mediated pathways. In addition, the role of salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) in Rpi-blb2-mediated HCD were analyzed by monitoring of the responses of NbICS1-, NbCOI1-, or NbEIN2-silenced or Rpi-blb2::NahG-transgenic plants. Rpi-blb2-mediated HCD in response to AVRblb2 was not associated with SA accumulation. Thus, SA affects Rpi-blb2-mediated resistance against P. infestans, but not Rpi-blb2-mediated HCD in response to AVRblb2. Additionally, JA and ET signaling were not required for Rpi-blb2-mediated HCD in N. benthamiana. Taken together, these findings suggest that NbSGT1 is a unique positive regulator of Rpi-blb2-mediated HCD in response to AVRblb2, but EDS1, NDR1, SA, JA, and ET are not required.

  9. Comparative transcriptome analysis between resistant and susceptible tomato allows the identification of lncRNA16397 conferring resistance to Phytophthora infestans by co-expressing glutaredoxin.

    Science.gov (United States)

    Cui, Jun; Luan, Yushi; Jiang, Ning; Bao, Hang; Meng, Jun

    2017-02-01

    The rapid development of omics sequencing technology has facilitated the identification of thousands of long non-coding (lnc)RNAs in plant species, but the role of lncRNAs in plant-pathogen interactions remains largely unexplored. We used comparative transcriptome analysis of Phytophthora infestans-resistant and -susceptible tomatoes to identify differentially expressed genes (DEGs) and lncRNAs (DELs), and examine lncRNA-mRNA networks. A total of 1037 DEGs and 688 DELs were identified between P. infestans-resistant and -susceptible tomatoes. The co-localization networks, including 128 DEGs and 127 DELs, were performed. We found that lncRNA16397 acted as an antisense transcript of SlGRX22 to regulate its expression, and also induced SlGRX21 expression when lncRNA16397 was overexpressed. In addition, disease symptoms and reactive oxygen species (ROS) accumulation in tomatoes overexpressing lncRNA16397 and SpGRX were fewer and lower than those in wild-type after P. infestans infection. This result suggests that tomato lncRNA16397 induces SlGRX expression to reduce ROS accumulation and alleviate cell membrane injury, resulting in enhanced resistance to P. infestans. Our results provide insight into lncRNAs involved in the response of tomato to P. infestans infection, demonstrate that the lncRNA16397-GRXs network is an important component of the P. infestans network in tomato, and provide candidates for breeding to enhance biotic stress-resistance in tomato.

  10. Nicotiana benthamiana calreticulin 3a is required for the ethylene-mediated production of phytoalexins and disease resistance against oomycete pathogen Phytophthora infestans.

    Science.gov (United States)

    Matsukawa, Mizuki; Shibata, Yusuke; Ohtsu, Mina; Mizutani, Aki; Mori, Hitoshi; Wang, Ping; Ojika, Makoto; Kawakita, Kazuhito; Takemoto, Daigo

    2013-08-01

    Mature Nicotiana benthamiana shows strong resistance to the potato late blight pathogen Phytophthora infestans. By screening using virus-induced random gene silencing, we isolated a gene for plant-specific calreticulin NbCRT3a as a required gene for resistance of N. benthamiana against P. infestans. NbCRT3a encodes an endoplasmic reticulum quality-control (ERQC) chaperone for the maturation of glycoproteins, including glycosylated cell-surface receptors. NbCRT3a-silenced plants showed no detectable growth defects but resistance to P. infestans was significantly compromised. Defense responses induced by the treatment with INF1 (a secretory protein of P. infestans), such as production of reactive oxygen species and accumulation of phytoalexins, were suppressed in NbCRT3a-silenced N. benthamiana. Expression of an ethylene-regulated gene for phytoalexin biosynthesis, NbEAS, was reduced in NbCRT3a-silenced plants, whereas the expression of salicylic acid-regulated NbPR-1a was not affected. Consistently, induction of ethylene production by INF1 was suppressed in NbCRT3a-silenced plants. Resistance reactions induced by a hyphal wall components elicitor prepared from P. infestans were also impaired in NbCRT3a-silenced plants. However, cell death induced by active mitogen-activated protein kinase kinase (NbMEK2(DD)) was not affected by the silencing of NbCRT3a. Thus, NbCRT3a is required for the initiation of resistance reactions of N. benthamiana in response to elicitor molecules derived from P. infestans.

  11. U-box E3 ubiquitin ligase PUB17 acts in the nucleus to promote specific immune pathways triggered by Phytophthora infestans.

    Science.gov (United States)

    He, Qin; McLellan, Hazel; Boevink, Petra C; Sadanandom, Ari; Xie, Conghua; Birch, Paul R J; Tian, Zhendong

    2015-06-01

    Ubiquitination regulates many processes in plants, including immunity. The E3 ubiquitin ligase PUB17 is a positive regulator of programmed cell death (PCD) triggered by resistance proteins CF4/9 in tomato. Its role in immunity to the potato late blight pathogen, Phytophthora infestans, was investigated here. Silencing StPUB17 in potato by RNAi and NbPUB17 in Nicotiana benthamiana by virus-induced gene silencing (VIGS) each enhanced P. infestans leaf colonization. PAMP-triggered immunity (PTI) transcriptional responses activated by flg22, and CF4/Avr4-mediated PCD were attenuated by silencing PUB17. However, silencing PUB17 did not compromise PCD triggered by P. infestans PAMP INF1, or co-expression of R3a/AVR3a, demonstrating that not all PTI- and PCD-associated responses require PUB17. PUB17 localizes to the plant nucleus and especially in the nucleolus. Transient over-expression of a dominant-negative StPUB17(V314I,V316I) mutant, which retained nucleolar localization, suppressed CF4-mediated cell death and enhanced P. infestans colonization. Exclusion of the StPUB17(V314I,V316I) mutant from the nucleus abolished its dominant-negative activity, demonstrating that StPUB17 functions in the nucleus. PUB17 is a positive regulator of immunity to late blight that acts in the nucleus to promote specific PTI and PCD pathways.

  12. Specific detection and quantification of virulent/avirulent Phytophthora infestans isolates using a real-time PCR assay that targets polymorphisms of the Avr3a gene.

    Science.gov (United States)

    Clément, J A J; Baldwin, T K; Magalon, H; Glais, I; Gracianne, C; Andrivon, D; Jacquot, E

    2013-05-01

    Molecular tools that allow intraspecific quantification and discrimination of pathogen isolates are useful to assess fitness of competitors during mixed infections. However, methods that were developed for quantifying Phytophthora infestans are only specific at the species level. Here, we reported a TaqMan-based real-time PCR assay allowing, according to the specificity of the used probes, an accurate quantification of different proportions of two genetically distinct clones of P. infestans in mixed fractions. Indeed, in addition to a primer specific to P. infestans, two primers and two TaqMan(®) probes that target single-nucleotide polymorphisms located in the Avr3a/avr3a virulence gene sequence were designed. The reliability of the method was tested on serially diluted fractions containing plasmid DNA with either the Avr3a or the avr3a sequences at concentrations ranging from 10(2) to 10(8)  copies per μl. Based on its specificity, sensitivity and repeatability, the proposed assay allowed a quantification of the targeted DNA sequence in fractions with a Avr3a/avr3a ratio in the range 1/99 to 99/1. The reliability of the test was also checked for counting zoospores. Applications for future research in P. infestans/host quantitative interactions were also discussed.

  13. Infection Efficiency of Four Phytophthora infestans Clonal Lineages and DNA-Based Quantification of Sporangia.

    Science.gov (United States)

    Fall, Mamadou Lamine; Tremblay, David Mathieu; Gobeil-Richard, Mélanie; Couillard, Julie; Rocheleau, Hélène; Van der Heyden, Hervé; Lévesque, Camile André; Beaulieu, Carole; Carisse, Odile

    2015-01-01

    The presence and abundance of pathogen inoculum is with host resistance and environmental conditions a key factor in epidemic development. Therefore, several spore-sampling devices have been proposed to monitor pathogen inoculum above fields. However, to make spore sampling more reliable as a management tool and to facilitate its adoption, information on infection efficiency and molecular tools for estimating airborne sporangia concentration are needed. Experiments were thus undertaken in a growth chamber to study the infection efficiency of four clonal lineages of P. infestans (US-8, US-11, US-23, and US-24) by measuring the airborne sporangia concentration and resulting disease intensity. The relationship between the airborne sporangia concentration and the number of lesions per leaf was exponential. For the same concentration, the sporangia of US-23 caused significantly more lesions than the sporangia of the other clonal lineages did. Under optimal conditions, an airborne sporangia concentration of 10 sporangia m-3 for US-23 was sufficient to cause one lesion per leaf, whereas for the other clonal lineages, it took 15 to 25 sporangia m-3 to reach the same disease intensity. However, in terms of diseased leaf area, there was no difference between clonal lineages US-8, US-23 and US-24. Also, a sensitive quantitative real-time polymerase chain reaction (qPCR) tool was developed to quantify P. infestans airborne sporangia with detection sensitivity of one sporangium. The specificity of the qPCR assay was rigorously tested for airborne inoculum and was either similar to, or an improvement on, other published PCR assays. This assay allows rapid and reliable detection and quantification of P. infestans airborne sporangia and thereby, facilitates the implementation of spores-sampling network.

  14. Mating type, mefenoxam sensitivity, and pathotype diversity in Phytophthora infestans isolates from tomato in Brazil Grupo de compatibilidade, sensibilidade ao mefenoxam e diversidade de patótipos de isolados de Phytophthora infestans de tomate no Brasil

    Directory of Open Access Journals (Sweden)

    Bruno Eduardo Cardozo de Miranda

    2010-07-01

    Full Text Available The objective of this work was to characterize 79 Phytophthora infestans isolates collected in tomato (Solanum lycopersicum fields, as to mating type, mefenoxam sensitivity, and pathotype composition. The isolates were sampled in 2006 and 2007 in seven Brazilian states as well as in the Distrito Federal. They were characterised as to mating type (n=79, sensitivity to fungicide mefenoxam (n=79, and virulence to three major resistance genes Ph-1, Ph-2, and Ph-3/Ph-4 (n=62. All isolates were of the mating type A1. Resistant isolates were detected in all sampled states, and its average frequency was superior to 50%. No difference was detected in pathotype diversity, neither between subpopulations collected in 2006 and 2007 nor between isolates grouped as resistant or intermediately sensitive to mefenoxam. All major resistance genes were overcome at different frequencies: Ph-1, 88.7%; Ph-2, 64.5%; and Ph-3/Ph-4, 25.8%. Isolates with virulence genes able to overcome all major resistance genes were detected at low frequencies. Tomato breeding programs in Brazil must avoid the development of cultivars with resistance based exclusively on major genes.O objetivo deste trabalho foi caracterizar 79 isolados de Phytophthora infestans, coletados em campos de tomate (Solanum lycopersicum, quanto ao grupo de compatibilidade, à sensibilidade ao mefenoxan, e à diversidade de patótipos. Os isolados foram obtidos em coletas realizadas nos anos de 2006 e 2007, em sete Estados do Brasil e no Distrito Federal. Os isolados foram usados para determinação do grupo de compatibilidade sexual (n=79, resistência ao fungicida mefenoxam (n=79 e espectro de virulência aos genes de efeito principal Ph-1, Ph-2 e Ph-3/Ph-4 (n=62. Todos os isolados foram classificados no grupo de compatibilidade A1. Isolados insensíveis ao fungicida mefenoxam foram detectados em todos os Estados amostrados, e apresentaram frequência média superior a 50%. Não houve diferença de

  15. Sensibilidad de aislamientos colombianos de Phytophthora infestans a cuatro fungicidas sistémicos

    Directory of Open Access Journals (Sweden)

    García Hibert Giovani

    2008-04-01

    Full Text Available

    La gota de la papa causada por Phytophthora infestans es la enfermedad más limitante de este cultivo en Colombia, donde la mayor parte de regiones productoras presentan condiciones óptimas para su desarrollo epidémico. Esta situación conduce a los agricultores a la utilización excesiva de diferentes fungicidas, lo que además de representar cerca del 10% de los costos de producción, causa un grave deterioro ambiental y de salud pública. Esta investigación pretende apoyar los programas de M.I.E. a partir del monitoreo de los niveles de sensibilidad de 15 aislamientos de P. infestans obtenidos en Antioquia, Cundinamarca y Boyacá a los fungicidas Ridomil® Gold, Curzate® M-8, Previcur® N SL y Mildex® 711 WG, como una herramienta de análisis de riesgos que permita ofrecer a los agricultores de papa recomendaciones técnicas basadas en la generación de líneas de sensibilidad. Las evaluaciones se realizaron utilizando la metodología de inmersión de discos de hoja con siete dosis de producto comercial. Los resultados indican que la población estudiada presenta altos niveles de sensibilidad a los cuatro fungicidas. Para el caso del Curzate® M-8, se alcanzaron valores promedio de EC50 de 0,28 mg·L-1, mientras que la EC50 para Previcur® N SL fue de 0,71 mg·L- 1. Para los fungicidas Ridomil® Gold y Mildex® 711 WG estos valores alcanzaron 0,62 y 0,54 mg·L- 1, respectivamente. Por otra parte, la producción de esporangios se redujo de 41.181 esporangios/mL obtenidos como promedio de todos los aislamientos en el tratamiento control, a menos de 500 esporangios/mL cuando se evaluaron las dosis máximas de los cuatro fungicidas.

  16. Genomic analyses of dominant U.S. clonal lineages of Phytophthora infestans reveals a shared common ancestry for clonal lineages US11 and US18 and a lack of recently shared ancestry among all other U.S. lineages

    Science.gov (United States)

    The populations of the potato and tomato late blight pathogen, Phytophthora infestans, in the US are well known for emerging repeatedly as novel clonal lineages. These successions of dominant clones have historically been named US1-US24, in order of appearance, since their first characterization usi...

  17. Physiological Race of Phytophthora infestans on Potato in Harbin%哈尔滨市马铃薯晚疫病菌生理小种的类型

    Institute of Scientific and Technical Information of China (English)

    高云飞; 郭梅; 王晓丹; 闵凡祥; 杨帅; 吕典秋; 张必弦; 陈磊

    2013-01-01

    Potato late blight, caused by Phytophtora infestans (Mont.) de Bary, is a catastrophic disease. In recent years, it occurs year after year, and tends to be more and more serious. In this research, 62 isolates, which were col ected from Harbin City in 2010, were identified in vitro assay for physiological race of Phytophtora infestans. The results showed that physiological races of Phytophthora infestans in Harbin City were composed of 14 types, with 1.3.4.7.8.10.11 being dominant (33.87% ) fol owed by 1.3.4.7.8 (14.52%) and 1.3.4.7 (12.90%), and the race with one virulent gene was not detected. These data suggest that the characteristics ofPhytophthora infestans populations on potato in Harbin City be diverse and complicated.%  马铃薯晚疫病是由致病疫霉菌[Phytophtora infestans(Mont.) de Bary]引起的毁灭性病害,近年来,该病害在哈尔滨市连年发生,危害日趋严重。本研究对2010年从哈尔滨市采集62个马铃薯晚疫病菌分离物进行了生理小种鉴定。结果表明,在62个分离物中,共有14个小种类型,以1.3.4.7.8.10.11小种为主,出现频率为33.87%,其次是小种1.3.4.7.8.和1.3.4.7,出现频率分别为14.52%和12.90%,没有鉴定出单基因小种。这充分说明,哈尔滨市致病疫霉菌毒力结构呈多样性,具有高度的复合性。

  18. Mandipropamid targets the cellulose synthase-like PiCesA3 to inhibit cell wall biosynthesis in the oomycete plant pathogen, Phytophthora infestans.

    Science.gov (United States)

    Blum, Mathias; Boehler, Martine; Randall, Eva; Young, Vanessa; Csukai, Michael; Kraus, Sabrina; Moulin, Florence; Scalliet, Gabriel; Avrova, Anna O; Whisson, Stephen C; Fonne-Pfister, Raymonde

    2010-03-01

    Oomycete plant pathogens cause a wide variety of economically and environmentally important plant diseases. Mandipropamid (MPD) is a carboxylic acid amide (CAA) effective against downy mildews, such as Plasmopara viticola on grapes and potato late blight caused by Phytophthora infestans. Historically, the identification of the mode of action of oomycete-specific control agents has been problematic. Here, we describe how a combination of biochemical and genetic techniques has been utilized to identify the molecular target of MPD in P. infestans. Phytophthora infestans germinating cysts treated with MPD produced swelling symptoms typical of cell wall synthesis inhibitors, and these effects were reversible after washing with H(2)O. Uptake studies with (14)C-labelled MPD showed that this oomycete control agent acts on the cell wall and does not enter the cell. Furthermore, (14)C glucose incorporation into cellulose was perturbed in the presence of MPD which, taken together, suggests that the inhibition of cellulose synthesis is the primary effect of MPD. Laboratory mutants, insensitive to MPD, were raised by ethyl methane sulphonate (EMS) mutagenesis, and gene sequence analysis of cellulose synthase genes in these mutants revealed two point mutations in the PiCesA3 gene, known to be involved in cellulose synthesis. Both mutations in the PiCesA3 gene result in a change to the same amino acid (glycine-1105) in the protein. The transformation and expression of a mutated PiCesA3 allele was carried out in a sensitive wild-type isolate to demonstrate that the mutations in PiCesA3 were responsible for the MPD insensitivity phenotype.

  19. BABA-primed defense responses to Phytophthora infestans in the next vegetative progeny of potato

    Directory of Open Access Journals (Sweden)

    Jolanta eFloryszak-Wieczorek

    2015-10-01

    Full Text Available The transcript of the PR1 gene accumulation as an informative marker of systemic acquired resistance (SAR was analyzed in β-aminobutyric acid (BABA primed potato in the short-lasting (3 days and long-lasting (28 days time periods after induction and in the vegetative descendants of primed plants derived from tubers and from in vitro seedlings. BABA pretreatment resulted either in minimal or no PR1 gene expression, but sequential treatment with BABA followed by virulent P. infestans provided data on the imprint of post-stress information and its duration until fertilization, in the form of an enhanced PR1 transcript accumulation and a transient increase of basal resistance to the late blight disease. The primed state for defense of the susceptible potato cultivar was transmitted to its vegetative progeny as a potentiated PR1 mRNA accumulation following challenge inoculation. However,variation was observed between vegetative accessions of the BABA-primed potato genotype in responsiveness to disease. In contrast to plants derived from tubers, potato propagated through in vitro seedlings largely lost inducible resistance traits, although itretained primed PR1 gene expression.

  20. The Population Structure of Phytophthora infestans from the Toluca Valley of Central Mexico Suggests Genetic Differentiation Between Populations from Cultivated Potato and Wild Solanum spp.

    Science.gov (United States)

    Flier, Wilbert G; Grünwald, Niklaus J; Kroon, Laurens P N M; Sturbaum, Anne K; van den Bosch, Trudy B M; Garay-Serrano, Edith; Lozoya-Saldaña, Hector; Fry, William E; Turkensteen, Lod J

    2003-04-01

    ABSTRACT The population structure of Phytophthora infestans in the Toluca Valley of central Mexico was assessed using 170 isolates collected from cultivated potatoes and the native wild Solanum spp., S. demissum and S. xendinense. All isolates were analyzed for mitochondrial DNA (mtDNA) haplotype and amplified fragment length polymorphism (AFLP) multi-locus fingerprint genotype. Isolate samples were monomorphic for mtDNA haplotype because all isolates tested were of the Ia haplotype. A total of 158 multilocus AFLP genotypes were identified among the 170 P. infestans isolates included in this study. P. infestans populations sampled in the Toluca Valley in 1997 were highly variable and almost every single isolate represented a unique genotype based on the analysis of 165 AFLP marker loci. Populations of P. infestans collected from the commercial potato-growing region in the valley, the subsistence potato production area along the slopes of the Nevado de Toluca, and the native Solanum spp. on the forested slopes of the volcano showed a high degree of genetic diversity. The number of polymorphic loci varied from 20.0 to 62.4% for isolates collected from the field station and wild Solanum spp. On average, 81.8% (135) of the AFLP loci were polymorphic. Hetero-zygosity varied between 7.7 and 19.4%. Significant differentiation was found at the population level between strains originating from cultivated potatoes and wild Solanum spp. (P = 0.001 to 0.022). Private alleles were observed in individual isolates collected from all three populations, with numbers of unique dominant alleles varying from 9 to 16 for isolates collected from commercial potato crops and native Solanum spp., respectively. Four AFLP markers were exclusively found present in isolates collected from S. demissum. Indirect estimation of gene flow between populations indicated restricted gene flow between both P. infestans populations from cultivated potatoes and wild Solanum hosts. There was no evidence

  1. Genomic characterization of a South American Phytophthora hybrid mandates reassessment of the geographic origins of Phytophthora infestans

    DEFF Research Database (Denmark)

    Martin, Michael David; Garrett Vieira, Filipe Jorge; Ho, Simon Y. W.;

    2016-01-01

    sequences, four of which represent a previously unknown basal lineage of P. infestans closely related to the famine-era lineage. Our analyses further reveal that clonal lineages of both P. andina and historical P. infestans diverged earlier than modern Mexican lineages, casting doubt on recent claims...... of a Mexican center of origin. Finally, we use haplotype phasing to demonstrate that basal branches of the clade comprising Mexican samples are occupied by clonal isolates collected from wild Solanum hosts, suggesting that modern Mexican P. infestans diversified on Solanum tuberosum after a host jump from...

  2. Loop-mediated isothermal amplification for detection of the tomato and potato late blight pathogen, Phytophthora infestans

    Science.gov (United States)

    Aims: To design and validate a colorimetric loop-mediated isothermal amplification assay for rapid detection of P. infestans DNA. Methods and Results: Two sets of LAMP primers were designed and evaluated for their sensitivity and specificity for P. infestans. ITSII primers targeted a portion of the ...

  3. 苯噻菌胺对致病疫霉的抑制作用%Inhibitive effect of Benthiavalicarb-isopropyl on Phytophthora infestans

    Institute of Scientific and Technical Information of China (English)

    刘利利; 张丽娟; 蒋选利; 王宏梅; 李红玫

    2009-01-01

    致病疫霉(Phytophthora infestans De Bary)是严重危害马铃薯和番茄的重要植物病原真菌,引起马铃薯和番茄的晚疫病,是一种毁灭性的世界蔬菜病害。美国、加拿大、法国、瑞士等国均报道该病危害严重,在我国山东、山西、河北等地也普遍发生。该病流行时间长,蔓延速度快,发病严重的田块,植株可在数日内死亡,造成严重减产甚至绝收。

  4. A Gene Expressed during Sexual and Asexual Sporulation in Phytophthora infestans is a Member of the Puf Family of Translational Regulators

    DEFF Research Database (Denmark)

    Cvitanich, Cristina; Judelson, Howard S.

    2003-01-01

    A gene from Phytophthora infestans that was previously identified as being induced during the development of sexual spores was also found to be active during asexual sporulation. The gene, M90, was expressed as a 3.1-kb primary transcript containing two introns and was predicted to encode a member...... of the Puf family of translational regulators. The protein showed up to 51% amino acid identity to other Puf proteins within its 353-amino-acid RNA-binding domain. Little similarity extended beyond this region, as noted for other members of the family. Expression of M90 was measured by using RNA blots....... Potential roles for a translational regulator during both sexual development and asexual sporulation are discussed....

  5. Monitoring of possible horizontal gene transfer from transgenic potatoes to soil microorganisms in the potato fields and the emergence of variants in Phytophthora infestans.

    Science.gov (United States)

    Kim, Sung Eun; Moon, Jae Sun; Kim, Jung Kyu; Yoo, Ran Hee; Choi, Won Sik; Lee, Eun Na; Lee, Sang Han; Kim, Sung Uk

    2010-06-01

    To examine the possibility of horizontal gene transfer between transgenic potatoes and microorganisms in potato fields, the gene flow from transgenic potatoes containing nucleoside diphosphate kinase 2 (NDPK2) gene to microorganisms in soils was investigated. The soil samples collected from the potato fields from March to October in 2007 were examined by PCR, Southern hybridization, and AFLP fingerprinting. The NDPK2 gene from soil genomic DNAs was not detected by both PCR and Southern hybridization, indicating that gene-transfer did not occur in the potato fields. In addition, no discrepancy was found in pathogenicity and noticeable changes for the appearance of variants of Phytophthora infestans in each generation when serial inoculations and the analysis of genomic DNAs by AFLP was conducted. Thus, these data suggest that transgenic potatoes do not give significant impacts on the communities of soil microorganisms and the emergence of variants although continued research efforts may be necessary to make a decisive conclusion.

  6. Infección mixta Phytophthora infestans-Virus x de la papa (PVX) y mecanismos de defensa en papa (Solanum tuberosum L.)

    OpenAIRE

    Héctor Lozoya Saldaña; Ma. Teresa Colinas León; Ma. Guadalupe Almanza Serrano

    2006-01-01

    Para identificar algunos mecanismos enzimáticos de resistencia en papa (Solanum tuberosum L.), se estudió la interacción de la infección mixta tizón tardío (Phytophthora infestans Mont., de Bary)-virus X de la papa (Potexvirus), sobre la actividad enzimática en las variedades Alpha y Zafiro, susceptible y resistente al tizón tardío, con o sin virus, y con o sin protección química (rotación semanal de dimetomorf-mancozeb, clorotalonilmetalaxil, y cymoxanil) en el Valle de Toluca, México. Al pr...

  7. The development and cultivation of tomatillo (Physalis ixocarpa Brot. under the climatic conditions of Poland. I. Local cultivars, growth of aboveground vegetative parts, probable resistance to Phytophthora infestans

    Directory of Open Access Journals (Sweden)

    Leszek S. Jankiewicz

    2013-12-01

    Full Text Available Tomatillo (Physalis ixocarpa Brot. grows in Poland much like in Mexico although its development cycle is much longer and lasts 6 months. It was sown at the beginning of April in a heated greenhouse, and transferred later on to a heated plastic tunnel. It was transplanted to a field about May 20 when danger of frosts had passed. Three local cultivars of Mexican origin were used and are briefly described. Their vegetative growth characteristics in Poland were similar to that of cv. Rendidora, which was described earlier in Mexico. The tomatillo internodes and leaves became progressively smaller with age. Tomatillo leaves and fruits were not attacked by Phytophthora infestans in the field and laboratory. Inoculation with tomato strains of this disease was without effect.

  8. Modification of primary and secondary metabolism of potato plants by nitrogen application differentially affects resistance to Phytophthora infestans and Alternaria solani.

    Science.gov (United States)

    Mittelstrass, K; Treutter, D; Plessl, M; Heller, W; Elstner, E F; Heiser, I

    2006-09-01

    Potato plants ( SOLANUM TUBEROSUM L. cv. Indira) were grown at two levels of N supply in the greenhouse. Plants supplied with 0.8 g N per plant (high N variant) showed significantly increased biomass as compared to plants without additional N fertilisation (low N variant). C/N ratio was lower and protein content was higher in leaves of the high N variant. The concentration of chlorogenic acids and flavonols was significantly lower in leaves from the high N variant. Whereas resistance to ALTERNARIA SOLANI increased when plants were supplied with additional nitrogen, these plants were more susceptible to PHYTOPHTHORA INFESTANS. After infection with both pathogens, we found a strong induction of p-coumaroylnoradrenaline and p-coumaroyloctopamine, which are identified for the first time in potato leaves and are discussed as resistance factors of other solanaceous plants.

  9. Phytophthora viruses.

    Science.gov (United States)

    Cai, Guohong; Hillman, Bradley I

    2013-01-01

    Phytophthora sp. is a genus in the oomycetes, which are similar to filamentous fungi in morphology and habitat, but phylogenetically more closely related to brown algae and diatoms and fall in the kingdom Stramenopila. In the past few years, several viruses have been characterized in Phytophthora species, including four viruses from Phytophthora infestans, the late blight pathogen, and an endornavirus from an unnamed Phytophthora species from Douglas fir. Studies on Phytophthora viruses have revealed several interesting systems. Phytophthora infestans RNA virus 1 (PiRV-1) and PiRV-2 are likely the first members of two new virus families; studies on PiRV-3 support the establishment of a new virus genus that is not affiliated with established virus families; PiRV-4 is a member of Narnaviridae, most likely in the genus Narnavirus; and Phytophthora endornavirus 1 (PEV1) was the first nonplant endornavirus at the time of reporting. Viral capsids have not been found in any of the above-mentioned viruses. PiRV-1 demonstrated a unique genome organization that requires further examination, and PiRV-2 may have played a role in late blight resurgence in 1980s-1990s.

  10. Overexpression of Camellia sinensis thaumatin-like protein, CsTLP in potato confers enhanced resistance to Macrophomina phaseolina and Phytophthora infestans infection.

    Science.gov (United States)

    Acharya, Karan; Pal, Awadhesh K; Gulati, Arvind; Kumar, Sanjay; Singh, Anil K; Ahuja, Paramvir S

    2013-06-01

    Thaumatin-like proteins (TLPs), a class of pathogenesis related proteins are induced in response to pathogens and exhibit antifungal property when overexpressed in transgenic plants. In the present study, we have raised transgenic potato plants overexpressing TLP gene of Camellia sinensis (CsTLP). Fungal resistance assays of transgenic potato elucidated the potential role of CsTLP in imparting tolerance to fungal pathogens, Macrophomina phaseolina (necrotrophic) and Phytophthora infestans (hemi-biotrophic). Transgenic tubers with higher resistance to M. phaseolina, showed a concomitant and significant increase in transcripts of StPAL, StLOX, and StTLP genes involved in phenylpropanoid, lipoxygenase, and general defense response pathway, respectively after infection. Importantly, leaves of CsTLP transgenic lines inoculated with P. infestans spores under in vitro conditions also showed a resistant phenotype. The resistant phenotype recorded for the two important fungal pathogens by CsTLP transgenic potato plants is remarkable, since no effective control methods and no resistant cv. against M. phaseolina has been identified so far in potato.

  11. Identification of three elicitins and a galactan-based complex polysaccharide from a concentrated culture filtrate of Phytophthora infestans efficient against Pectobacterium atrosepticum.

    Science.gov (United States)

    Saubeau, Guillaume; Gaillard, Fanny; Legentil, Laurent; Nugier-Chauvin, Caroline; Ferrières, Vincent; Andrivon, Didier; Val, Florence

    2014-09-26

    The induction of plant immunity by Pathogen Associated Molecular Patterns (PAMPs) constitutes a powerful strategy for crop protection. PAMPs indeed induce general defense responses in plants and thus increase plant resistance to pathogens. Phytophthora infestans culture filtrates (CCFs) are known to induce defense responses and decrease the severity of soft rot due to Pectobacterium atrosepticum in potato tubers. The aim of this study was to identify and characterize the active compounds from P. infestans filtrate. The filtrate was fractionated by gel filtration, and the protection effects against P. atrosepticum and the ability to induce PAL activity were tested for each fraction. The fraction active in protection (F1) also induced PAL activity, as did the whole filtrate. Three elicitins (INF1, INF4 and INF5) were identified in F1b, subfraction of F1, by MALDI-TOF-MS and MS/MS analyses. However, deproteinized F1b still showed biological activity against the bacterium, revealing the presence of an additional active compound. GC-MS analyses of the deproteinized fraction highlighted the presence of a galactan-based complex polysaccharide. These experiments demonstrate that the biological activity of the CCF against P. atrosepticum results from a combined action of three elicitins and a complex polysaccharide, probably through the activation of general defense responses.

  12. Identification of Three Elicitins and a Galactan-Based Complex Polysaccharide from a Concentrated Culture Filtrate of Phytophthora infestans Efficient against Pectobacterium atrosepticum

    Directory of Open Access Journals (Sweden)

    Guillaume Saubeau

    2014-09-01

    Full Text Available The induction of plant immunity by Pathogen Associated Molecular Patterns (PAMPs constitutes a powerful strategy for crop protection. PAMPs indeed induce general defense responses in plants and thus increase plant resistance to pathogens. Phytophthora infestans culture filtrates (CCFs are known to induce defense responses and decrease the severity of soft rot due to Pectobacterium atrosepticum in potato tubers. The aim of this study was to identify and characterize the active compounds from P. infestans filtrate. The filtrate was fractionated by gel filtration, and the protection effects against P. atrosepticum and the ability to induce PAL activity were tested for each fraction. The fraction active in protection (F1 also induced PAL activity, as did the whole filtrate. Three elicitins (INF1, INF4 and INF5 were identified in F1b, subfraction of F1, by MALDI-TOF-MS and MS/MS analyses. However, deproteinized F1b still showed biological activity against the bacterium, revealing the presence of an additional active compound. GC-MS analyses of the deproteinized fraction highlighted the presence of a galactan-based complex polysaccharide. These experiments demonstrate that the biological activity of the CCF against P. atrosepticum results from a combined action of three elicitins and a complex polysaccharide, probably through the activation of general defense responses.

  13. Gene Expression and Silencing Studies in Phytophthora infestans Reveal Infection-Specific Nutrient Transporters and a Role for the Nitrate Reductase Pathway in Plant Pathogenesis

    Science.gov (United States)

    Ah-Fong, Audrey M. V.; Davis, Carol; Andreeva, Kalina; Judelson, Howard S.

    2016-01-01

    To help learn how phytopathogens feed from their hosts, genes for nutrient transporters from the hemibiotrophic potato and tomato pest Phytophthora infestans were annotated. This identified 453 genes from 19 families. Comparisons with a necrotrophic oomycete, Pythium ultimum var. ultimum, and a hemibiotrophic fungus, Magnaporthe oryzae, revealed diversity in the size of some families although a similar fraction of genes encoded transporters. RNA-seq of infected potato tubers, tomato leaves, and several artificial media revealed that 56 and 207 transporters from P. infestans were significantly up- or down-regulated, respectively, during early infection timepoints of leaves or tubers versus media. About 17 were up-regulated >4-fold in both leaves and tubers compared to media and expressed primarily in the biotrophic stage. The transcription pattern of many genes was host-organ specific. For example, the mRNA level of a nitrate transporter (NRT) was about 100-fold higher during mid-infection in leaves, which are nitrate-rich, than in tubers and three types of artificial media, which are nitrate-poor. The NRT gene is physically linked with genes encoding nitrate reductase (NR) and nitrite reductase (NiR), which mobilize nitrate into ammonium and amino acids. All three genes were coregulated. For example, the three genes were expressed primarily at mid-stage infection timepoints in both potato and tomato leaves, but showed little expression in potato tubers. Transformants down-regulated for all three genes were generated by DNA-directed RNAi, with silencing spreading from the NR target to the flanking NRT and NiR genes. The silenced strains were nonpathogenic on leaves but colonized tubers. We propose that the nitrate assimilation genes play roles both in obtaining nitrogen for amino acid biosynthesis and protecting P. infestans from natural or fertilization-induced nitrate and nitrite toxicity. PMID:27936244

  14. INHIBITION OF FUNGAL FERMENTED FILTRATES ON PHYTOPHTHORA INFESTANS%几种真菌发酵液对致病疫霉的抑制作用

    Institute of Scientific and Technical Information of China (English)

    蒋继志; 赵丽坤; 史娟; 董金皋

    2001-01-01

    Effect of 8 fungal fermented filtrates on mycelial growth, encystment and germination of zoospores, appressorium formation, and penetration hyphae formation of Phytophthora infestans was investigated. Of which, the fermented filtrates from Rhizoctonia solani and Colletotrichum gloeosporioides showed the strongest inhibition against P. infestans. The results indicated that they are potential for controlling the diseases caused by P. infestans.%测定了8种真菌发酵液在5种不同浓度下对致病疫霉菌丝生长、游动孢子静止、静止胞萌发、附着胞形成和侵入丝形成等不同阶段的影响。结果表明,供试真菌不同浓度的发酵液,对致病疫霉上述各个阶段均有一定程度的抑制作用,并均随发酵液浓度增加,抑制作用逐渐增强,浓度为100%时,抑制作用均达到最高。其中,立枯丝核菌发酵液的抑制作用最强,浓度为100%时,对致病疫霉菌丝生长的抑制率达到90.4%,而静止胞萌发率仅为2.4%,附着胞及侵入丝均未见形成。

  15. bZIP transcription factors in the oomycete phytophthora infestans with novel DNA-binding domains are involved in defense against oxidative stress.

    Science.gov (United States)

    Gamboa-Meléndez, Heber; Huerta, Apolonio I; Judelson, Howard S

    2013-10-01

    Transcription factors of the basic leucine zipper (bZIP) family control development and stress responses in eukaryotes. To date, only one bZIP has been described in any oomycete; oomycetes are members of the stramenopile kingdom. In this study, we describe the identification of 38 bZIPs from the Phytophthora infestans genome. Half contain novel substitutions in the DNA-binding domain at a site that in other eukaryotes is reported to always be Asn. Interspecific comparisons indicated that the novel substitutions (usually Cys, but also Val and Tyr) arose after oomycetes diverged from other stramenopiles. About two-thirds of P. infestans bZIPs show dynamic changes in mRNA levels during the life cycle, with many of the genes being upregulated in sporangia, zoospores, or germinated zoospore cysts. One bZIP with the novel Cys substitution was shown to reside in the nucleus throughout growth and development. Using stable gene silencing, the functions of eight bZIPs with the Cys substitution were tested. All but one were found to play roles in protecting P. infestans from hydrogen peroxide-induced injury, and it is proposed that the novel Cys substitution serves as a redox sensor. A ninth bZIP lacking the novel Asn-to-Cys substitution, but having Cys nearby, was also shown through silencing to contribute to defense against peroxide. Little effect on asexual development, plant pathogenesis, or resistance to osmotic stress was observed in transformants silenced for any of the nine bZIPs.

  16. Identification and analysis of mitochondrial haplotypes on potato Phytophthora infestans in Qinghai area%青海马铃薯晚疫病菌线粒体DNA单倍型鉴定及分析

    Institute of Scientific and Technical Information of China (English)

    连延浩; 叶广继; 王舰

    2012-01-01

    To detect the distribution of mitochondrial haplotypes of Phytophthora infestans in Qinghai Province, 70 isolates of Phytophthora infestans collected from different areas in 2006 -2007 were identified and analyzed. The results showed that the type Ua was the most important, accounting for 94.3% , and the rest 5. 7% belong to the type lib. The type lib strains were all isolated from tomato plants. The results showed that the type IIa was the major potato Phytophthora infestans strain in Qinghai, and its mitochondrial haplotype was simplistic.%为查明青海地区晚疫病菌单倍型分布情况,本研究对青海不同地区采自2006~2007年的70个晚疫病菌材料的线粒体单倍型进行了分析,结果表明:94.3%的菌株为Ⅱa型,5.7%的菌株为Ⅱb型,其中Ⅱb型均分离自番茄.这说明青海地区马铃薯晚疫病菌群体类型比较单一,主要为Ⅱa型,线粒体单倍型不存在多态性.

  17. IDENTIFICATION OF KEY MOLECULAR COMPONENTS OF THE RESISTANCE OF CHERRY TOMATO AGAINSTPhytophthora infestans Identificación de los principales componentes moleculares de la resistencia de tomate cherry contra Phytophthora infestans

    Directory of Open Access Journals (Sweden)

    LILIANA LÓPEZ KLEINE

    2012-12-01

    Full Text Available Cherry tomato Solanum lycopersicum var cerasiforme cv Matt's wild cherry is a very resistant cultivar to most Phytophthora infestans isolates. Two isolates were identified, US940480 and US970001 that cause an incompatible and a compatible interaction respectively. US970001 is one of the few isolates producing a compatible interaction with this cultivar. To identify genes with a differential gene expression between compatible and incompatible interactions, gene expression patterns were analyzed with tomato cDNA microarrays including 12,899 independent tomato cDNA clones at different time points after inoculation. A diverse set of statistical tools were used to identify key components of the plant response to the pathogen. Forty-three genes were up-regulated during the incompatible reaction at time point 36 hours, 15 globally at all time points and twelve were found both in globally and at 36 hours. Northern blots analysis was performed to confirm differential expression showed by microarray analysis and to study the differential expression of more plant resistance genes (PR genes between compatible and incompatible interactions for this interaction.El tomate cherry Solanum lycopersicum var cerasiforme cv Matt's es bastante resistente a la gran parte de aislamientos de Phytophthora infestans. Se han identificado dos aislamientos, US940480 y US970001 que causan interacción incompatible y compatible respectivamente. US970001 es uno de los pocos aislamientos causantes de interacción compatible con este cultivo. Con el fin de identificar genes con expresión diferencial en interacciones compatible e incompatible, analizamos DNA copia de 12899 clones independientes en tres tiempos posteriores a la inoculación del patógeno. Se aplicaron diversas herramientas estadísticas para identificar componentes moleculares claves de la respuesta de la planta al patógeno. Cuarenta y tres genes fueron detectados como activados durante la interacci

  18. Population structure of Phytophthora infestans from Ningxia%宁夏固原致病疫霉群体结构特征

    Institute of Scientific and Technical Information of China (English)

    宋俊丽; 朱杰华; 杨志辉; 王春一

    2012-01-01

    为揭示宁夏固原致病疫霉群体遗传结构,用对峙培养法和菌落直径法测定致病疫霉的交配型和甲霜灵抗性,利用限制性片段长度多态性聚合酶链反应(PCR-RFLP)技术检测致病疫霉线粒体DNA单倍型,并采用简单重复序列(SSR)和扩增片段长度多态性(AFLP)技术确定致病疫霉群体的基因型。在94株供试菌株中,发现了1株A1交配型、86株A2交配型及7株自育型菌株,全部为甲霜灵抗性菌株。菌株的线粒体单倍型均为Ⅰa型,共鉴定出2种SSR基因型,Ⅰ型占绝对优势。AFLP聚类分析显示,在相似系数0.68时分成α和β两组,宁夏固原菌株全部聚在β组。研究表明,宁夏固原致病疫霉群体结构比较单一、遗传多样性水平较低。%The population genetic structure of Phytophthora infestans collected from Guyuan of Ningxia Hui Autonomous Region was revealed by the combination of phenotypes and genotypes. The phenotypes of P. infestans i.e. mating types and metalaxyl resistance were investigated by means of dual culture with A1 and 3,2 testers on rye plates and radical growth assay on fungicide-amended media in vitro, respec- tively. Mitochondrial DNA haplotypes of isolates of P. infestans were detected with restriction fragment length polymorphism and polymerase chain reaction (PCR-RFLP). Genotypes of genomic total DNA of P. infestans were examined by simple sequence repeats (SSR) and amplified fragment length polymor- phism (AFLP). Of tested 94 isolates, only one was A1, 86 ones were A2, and the seven ones were self- fertile. Nevertheless, all tested isolates were metalaxyl-resistant. Only one mitochondrial DNA haplotype ( I a) and two SSR genotypes ( named as types I and II ) were determined among population, one ( i. e. type I ) of which was absolute predominance. Then, two AFLP clades (i. e. α and β clade) were formed at a genetic similarity value of 0. 68 and all isolates of P. infestans from Guyuan of Ningxia were

  19. Effect of Temperature on Growth and Sporulation of US-22, US-23, and US-24 Clonal Lineages of Phytophthora infestans and Implications for Late Blight Epidemiology.

    Science.gov (United States)

    Seidl Johnson, Anna C; Frost, Kenneth E; Rouse, Douglas I; Gevens, Amanda J

    2015-04-01

    Epidemics of late blight, caused by Phytophthora infestans (Mont.) de Bary, have been studied by plant pathologists and regarded with great concern by potato and tomato growers since the Irish potato famine in the 1840s. P. infestans populations have continued to evolve, with unique clonal lineages arising which differ in pathogen fitness and pathogenicity, potentially impacting epidemiology. In 2012 and 2013, the US-23 clonal lineage predominated late blight epidemics in most U.S. potato and tomato production regions, including Wisconsin. This lineage was unknown prior to 2009. For isolates of three recently identified clonal lineages of P. infestans (US-22, US-23, and US-24), sporulation rates were experimentally determined on potato and tomato foliage and the effect of temperature on lesion growth rate on tomato was investigated. The US-22 and US-23 isolates had greater lesion growth rates on tomato than US-24 isolates. Sporulation rates for all isolates were greater on potato than tomato, and the US-23 isolates had greater sporulation rates on both tomato and potato than the US-22 and US-24 isolates. Experimentally determined correlates of fitness were input to the LATEBLIGHT model and epidemics were simulated using archived Wisconsin weather data from four growing seasons (2009 to 2012) to investigate the effect of isolates of these new lineages on late blight epidemiology. The fast lesion growth rates of US-22 and US-23 isolates resulted in severe epidemics in all years tested, particularly in 2011. The greater sporulation rates of P. infestans on potato resulted in simulated epidemics that progressed faster than epidemics simulated for tomato; the high sporulation rates of US-23 isolates resulted in simulated epidemics more severe than simulated epidemics of isolates of the US-22 and US-24 isolates and EC-1 clonal lineages on potato and tomato. Additionally, US-23 isolates consistently caused severe simulated epidemics when lesion growth rate and sporulation

  20. Efficient disruption and replacement of an effector gene in the oomycete Phytophthora sojae using CRISPR/Cas9.

    Science.gov (United States)

    Fang, Yufeng; Tyler, Brett M

    2016-01-01

    Phytophthora sojae is an oomycete pathogen of soybean. As a result of its economic importance, P. sojae has become a model for the study of oomycete genetics, physiology and pathology. The lack of efficient techniques for targeted mutagenesis and gene replacement have long hampered genetic studies of pathogenicity in Phytophthora species. Here, we describe a CRISPR/Cas9 system enabling rapid and efficient genome editing in P. sojae. Using the RXLR effector gene Avr4/6 as a target, we observed that, in the absence of a homologous template, the repair of Cas9-induced DNA double-strand breaks (DSBs) in P. sojae was mediated by non-homologous end-joining (NHEJ), primarily resulting in short indels. Most mutants were homozygous, presumably as a result of gene conversion triggered by Cas9-mediated cleavage of non-mutant alleles. When donor DNA was present, homology-directed repair (HDR) was observed, which resulted in the replacement of Avr4/6 with the NPT II gene. By testing the specific virulence of several NHEJ mutants and HDR-mediated gene replacements in soybean, we have validated the contribution of Avr4/6 to recognition by soybean R gene loci, Rps4 and Rps6, but also uncovered additional contributions to resistance by these two loci. Our results establish a powerful tool for the study of functional genomics in Phytophthora, which provides new avenues for better control of this pathogen.

  1. Selection of candidate genes involved in the defense mechanisms of Phytophthora infestans against fungicides by EST analysis

    Science.gov (United States)

    Preliminary research using a functional genomics approach was conducted to gain insights on how P. infestans responds to fungicides and the possible implications of these responses on its ability to adapt to such selection pressure. Two isolates with subtle differences in mefenoxam resistance were e...

  2. Selection and validation of potato candidate genes for maturity corrected resistance to Phytophthora infestans based on differential expression combined with SNP association and linkage mapping

    Directory of Open Access Journals (Sweden)

    Meki Shehabu Muktar

    2015-09-01

    Full Text Available Late blight of potato (Solanum tuberosum L. caused by the oomycete Phytophthora infestans (Mont. de Bary, is one of the most important bottlenecks of potato production worldwide. Cultivars with high levels of durable, race unspecific, quantitative resistance are part of a solution to this problem. However, breeding for quantitative resistance is hampered by the correlation between resistance and late plant maturity, which is an undesirable agricultural attribute. The objectives of our research are (i the identification of genes that condition quantitative resistance to P. infestans not compromised by late plant maturity and (ii the discovery of diagnostic single nucleotide polymorphism (SNP markers to be used as molecular tools to increase efficiency and precision of resistance breeding. Twenty two novel candidate genes were selected based on comparative transcript profiling by SuperSAGE (serial analysis of gene expression in groups of plants with contrasting levels of maturity corrected resistance (MCR. Reproducibility of differential expression was tested by quantitative real time PCR and allele specific pyrosequencing in four new sets of genotype pools with contrasting late blight resistance levels, at three infection time points and in three independent infection experiments. Reproducibility of expression patterns ranged from 28% to 97%. Association mapping in a panel of 184 tetraploid cultivars identified SNPs in five candidate genes that were associated with MCR. These SNPs can be used in marker-assisted resistance breeding. Linkage mapping in two half-sib families (n = 111 identified SNPs in three candidate genes that were linked with MCR. The differentially expressed genes that showed association and/or linkage with MCR putatively function in phytosterol synthesis, fatty acid synthesis, asparagine synthesis, chlorophyll synthesis, cell wall modification and in the response to pathogen elicitors.

  3. Diversidad genética de aislamientos de Phytophthora infestans en plantaciones de papa en Costa Rica con el uso de RAPDs

    Directory of Open Access Journals (Sweden)

    Oswaldo P\\u00E1ez

    2005-01-01

    Full Text Available Para determinar la diversidad genética de Phytophthora infestans en Costa Rica, 62 aislamientos de este patógeno fueron recolectados en plantaciones de papa en las zonas de Cartago, Zarcero, Fraijanes y Heredia durante 1999-2001 y analizados con el uso de RAPDs. Todos los aislamientos fueron previamente evaluados para el tipo de apareamiento y la resistencia al metalaxyl. Se seleccionó 11 imprimadores con los cuales fue posible formar 17 grupos RAPD cuyas frecuencias variaron de 0,55 a 0,02. En el grupo más frecuente se encontró aislamientos resistentes y sensibles provenientes de todas las zonas muestreadas. Todos los aislamientos en los 17 grupos mostraron una alta relación genética. La mayor diversidad genética se encontró entre aislamientos y no se observó ninguna sub-estructuración poblacional de acuerdo a las zonas o sensibilidad al metalaxyl. Al comparar los aislamientos costarricenses con los aislamientos foráneos US-1, US-18 y EC-1, no se observó ninguna relación genética entre ambas poblaciones; de hecho, el coeficiente de diferenciación genética Gst mostró que la población local es diferente a la de los aislamientos foráneos. El análisis con los RAPDs reveló que la población de P. infestans, en las plantaciones de papa en Costa Rica, es diversa aunque probablemente los aislamientos comparten un ancestro en común.

  4. Molecular detection of Phytophthora infestans based on Ypt1 gene%以Ypt1基因为靶标的致病疫霉菌Phytophthora infestans的分子检测

    Institute of Scientific and Technical Information of China (English)

    孟军

    2012-01-01

    Yptl is a Ras-related gene, in yeast, the gene encoding a protein associated with GTP binding. In this study, over 30 oomycetes Yptl DNA sequences were compared and a pair of primers (Pil/Pi2) was designed for detecting P. Infestans. 144 isolates representing 26 species of Phytophthora and 29 fungal species of plant pathogens were used to test the specificity of the primers. PCR amplification with species-specific (Pi) primers resulted in a product of 369 bp only from isolates of P. Infestans. The detection sensitivity with Pi primers was 100 pg of genomic DNA. Using YptlF/YptlR as first-round amplification primers, followed by a second round using the primer pair Pil/Pi2, a nested PCR procedure was developed, which increased the detection sensitivity 10-fold to 10 pg. For primers Pil/Pi2, one oospore or 3 zoospores could be detected by nested PCR. The results showed that Yptl gene could be a molecular target for detection of P. Infestans. PCR with the Pi primers could also be used to detect P. Infestans from naturally infected potato tissues and diseased soil samples.%三磷酸鸟苷(GTP)结合蛋白基因(Ypt1)是一个与原癌基因Ras(Rat sarcoma)相关的基因,在酵母中,该基因编码一个与Ras相关GTP结合蛋白.为了研究以Ypt1基因为分子靶标的致病疫霉菌(P.infestans)检测技术,比较了30种卵菌Ypt1基因的序列,以该序列为靶标设计了1对针对P.infestans的特异性PCR引物Pi1/Pi2.试验结果表明,在供试的55种不同疫霉菌和真菌的144个菌株中,利用这1对引物只能从P.infestans基因组DNA中分别扩增出1条分子量为369 bp的特异性条带,这1对引物的检测灵敏度为100 pg.以疫霉菌Ypt1通用引物Yph1F/Yph2R结合这1对特异引物进行套式PCR扩增,使引物Pi1/Pi2的检测灵敏度提高了10倍,检测到10 pg的基因组DNA.通过套式PCR,引物Pi1/Pi2对游动孢子和卵孢子的检测灵敏度分别为3个游动孢子和1个卵孢子;以Pi1/Pi2引物,分别采用单

  5. Marker-assisted selection of diploid and tetraploid potatoes carrying Rpi-phu1, a major gene for resistance to Phytophthora infestans.

    Science.gov (United States)

    Sliwka, J; Jakuczun, H; Kamiński, P; Zimnoch-Guzowska, E

    2010-01-01

    The Rpi-phu1 gene originates from an interspecific hybrid between Solanum stenotomum and S. phureja, and confers a high level of resistance to Phytophthora infestans (late blight) in potato. The Rpi-phu1 was introduced by crossing at the diploid level into the S. tuberosum gene pool and then transferred to the tetraploid level by means of 2n gametes. Tetraploid lines carrying the Rpi-phu1 were selected for further crosses. A molecular marker GP94, linked in mapping population 97-30 with the Rpi-phu1 (6.4 cM), was applied to other unselected populations (2 diploid and 1 tetraploid), and was shown to be useful in marker-assisted selection (MAS) of the resistant individuals. GP94 was applied also in commercial breeding in 2 tetraploid populations. Although the marker allele of GP94, characteristic for the Rpi-phu1 presence, was rare in the S. tuberosum gene pool, it seemed to be common in 2 other sources of resistance to late blight: S. ruiz-ceballosii and S. kurtzianum.

  6. Development of a bipartite ecdysone-responsive gene switch for the oomycete Phytophthora infestans and its use to manipulate transcription during axenic culture and plant infection.

    Science.gov (United States)

    Gamboa-Meléndez, Heber; Judelson, Howard S

    2015-01-01

    Conditional expression systems have been proven to be useful tools for the elucidation of gene function in many taxa. Here, we report the development of the first useful inducible promoter system for an oomycete, based on an ecdysone receptor (EcR) and the ecdysone analogue methoxyfenozide. In Phytophthora infestans, the potato late blight pathogen, a monopartite transactivator containing the VP16 activation domain from herpes simplex virus, the GAL4 DNA-binding domain from yeast and the EcR receptor domain from the spruce budworm enabled high levels of expression of a β-glucuronidase (GUS) reporter gene, but unacceptable basal activity in the absence of the methoxyfenozide inducer. Greatly improved performance was obtained using a bipartite system in which transcription is activated by a heterodimer between a chimera of VP16 and the migratory locust retinoid X receptor, and a separate EcR-DNA-binding domain chimera. Transformants were obtained that exhibited >100-fold activation of the reporter by methoxyfenozide, with low basal levels of expression and induced activity approaching that of the strong ham34 promoter. Performance varied between transformants, probably as a result of position effects. The addition of methoxyfenozide enabled strong induction during hyphal growth, zoosporogenesis and colonization of tomato. No significant effects of the inducer or transactivators on growth, development or pathogenicity were observed. The technology should therefore be a useful addition to the arsenal of methods for the study of oomycete plant pathogens.

  7. Evaluation de la résistance de certaines variétés de pomme de terre biologique au mildiou Phytophthora infestans (Mont de Bary

    Directory of Open Access Journals (Sweden)

    Ferjaoui, S.

    2010-01-01

    Full Text Available Evaluation of the Resistance of some Varieties of Biological Potato to the Mildew Phytophthora infestans. To control the mildew, in particular in biological productions, the varietal resistance of potato could be an advantage to associate with other cultural measurements. For this purpose, sixteen varieties potentially interesting in conventional and biological production were tested with regard to the mildew. Eleven varieties were subscribed in the list A (Alaska, Arinda, Baraka, Fabula, Liseta, Mondial, Platina, Safrane, Santana, Spunta and Timate and five are in the process of evaluation (Carréra, Cicéro, Derby, Vivaldi, and Voyager. It seemed that the mildew affected all the tested varieties. However, some of them appeared more tolerant than others. Indeed, the Derby and Voyager varieties revealed to be able to delay the starting of the disease of one month. Cicéro, Vivaldi and Timate could delay the development of mildew disease of twelve days, relatively to its appearance on susceptible varieties. Furthermore, the foliar level of destruction remained very limited compared to that on susceptible varieties and not exceed 10% for Timate. The varieties Fabula, Liséta, Carréra, Mondial, Spunta, Platina, Safrane, Arinda, Santana and Baraka showed an early and fast starting of the epidemy. In addition, the tolerance or varietal resistance could not resolve the problem when tubers are affected, since a relatively weak rate of leaves contamination is enough to cause a very important economic loss on the tubers.

  8. 木醋液对马铃薯晚疫病菌的抑制作用%Inhibition Effects of Wood Vinegar on Phytophthora infestans

    Institute of Scientific and Technical Information of China (English)

    马骏; 刘霞; 王洪洋; 杨艳丽

    2011-01-01

    The inhibition effects of wood vinegar on Phytophthora infestans were studied by adding different concentrations of wood vinegar in the rye culture medium. The results showed that the mycelia growth rate was inhibited by over 2% wood vinegar concentrations, however, the mycelia growth and sporangia formation were promoted by 0.1% concentration of wood vinegar. The sporangia formation was promoted by 0.2% wood vinegar concentrations, but for the mycelia growth, the difference was not significant.%通过在黑麦培养基中添加不同浓度的木醋液,研究木醋液对马铃薯晚疫病菌的抑菌作用。结果表明,2%以上浓度的木醋液对菌丝生长有明显的抑制作用,而0.1%浓度的木醋液反而对菌丝生长和孢子囊的形成有促进作用,0.2%浓度的木醋液虽然对菌丝生长影响不显著,但对孢子囊的形成仍然有促进作用。

  9. Identificación de Genes R1 y R2 que confieren resistencia a Phytophthora infestans en genotipos colombianos de papa Identification of R1 and R2 Genes conferring resistance to Phytophthora infestans in Colombian potato genotypes

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    Núñez Víctor M.

    2003-12-01

    Full Text Available En Colombia, actualmente existen genotipos de papa con excelente calidad industrial pero muy susceptibles a P. infestans. La mejor manera de combatir este problema es mediante resistencia genética, puesto que la inversión para controlar esta enfermedad por medios químicos es muy costosa, sin olvidar la contaminación ambiental que producen. El objetivo de este trabajo fue la identificación de genes R1 y R2 en los diferenciales de papa respectivos (Solanum tuberosum ssp. tuberosum mediante evaluación de resistencia a P. infestans y la detección molecular por medio de PCR (alelo R1 y AFLP (alelo R2. Para la detección del alelo R1 fueron empleados los primers GP179, GP21, 76-2SF2/76-2SR, SPUD237 y Sol 2749-2770F / Sol 3246-3267R. Los primers GP179, GP21 y SPUD237 fueron inespecíficos para Rl, ya que se generó un producto de amplificación en los diferenciales 1 y 2, así como también en Solanum phureja. Los primers 76-2SF2/76-2SR, y Sol 2749-2770F / Sol 3246-3267R generaron un producto de amplificación en los diferenciales 1 y 2; por el contrario, el fragmento estuvo ausente en el material susceptible. Para la detección del alelo R2, fueron implementados cinco marca­dores AFLP, de los cuales sólo dos fueron reconocidos visualmente en el diferencial 2. Los resultados mostra­ron una evidente correspondencia fenotípica y genotípica con respecto a la presencia de los genes Rl y R2. La identificación molecular de genes de resistencia a P. infestans permitirá desarrollar programas de mejoramiento genético que beneficien directamente los rendimientos de los cultivos de papa, sobre todo los de mayor interés industrial para nuestro país.Excellent industrial quality potato genotypes are currently available in Colombia; however, they are very sus­ceptible to P. infestans. The best way of fighting this problem is by genetic resistance, given that the expense of controlling this disease through chemicals is high, plus the environmental

  10. Time-course investigation of Phytophthora infestans infection of potato leaf from three cultivars by quantitative proteomics

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    Mia Kruse Guldstrand Larsen

    2016-03-01

    We used label-free quantitative proteomics to investigate the infection with P. infestans in a time-course study over 258 h. Several key issues limits proteome analysis of potato leaf tissue [5–7]. Firstly, the immense complexity of the plant proteome, which is further complicated by the presence of highly abundant proteins, such as ribulose bisphosphate carboxylase/oxygenase (RuBisCO. Secondly, plant leaf and potato, in particular, contain abundant levels amounts of phenols and polyphenols, which hinder or completely prevent a successful protein extraction. Hitherto, protein profiling of potato leaf tissues have been limited to few proteome studies and only 1484 proteins have been extracted and comprehensively described [5,8,9]. We here present the detailed methods and raw data by optimized gel-enhanced label free quantitative approach. The methodology enabled us to detect and quantify between 3248 and 3529 unique proteins from each cultivar, and up to 758 P. infestans derived proteins. The complete dataset is available via ProteomeXchange, with the identifier PXD002767.

  11. Genetic analysis of environmental strains of the plant pathogen Phytophthora capsici reveals heterogeneous repertoire of effectors and possible effector evolution via genomic island.

    Science.gov (United States)

    Iribarren, María Josefina; Pascuan, Cecilia; Soto, Gabriela; Ayub, Nicolás Daniel

    2015-11-01

    Phytophthora capsici is a virulent oomycete pathogen of many vegetable crops. Recently, it has been demonstrated that the recognition of the RXLR effector AVR3a1 of P. capsici (PcAVR3a1) triggers a hypersensitive response and plays a critical role in mediating non-host resistance. Here, we analyzed the occurrence of PcAVR3a1 in 57 isolates of P. capsici derived from globe squash, eggplant, tomato and bell pepper cocultivated in a small geographical area. The occurrence of PcAVR3a1 in environmental strains of P. capsici was confirmed by PCR in only 21 of these pathogen isolates. To understand the presence-absence pattern of PcAVR3a1 in environmental strains, the flanking region of this gene was sequenced. PcAVR3a1 was found within a genetic element that we named PcAVR3a1-GI (PcAVR3a1 genomic island). PcAVR3a1-GI was flanked by a 22-bp direct repeat, which is related to its site-specific recombination site. In addition to the PcAVR3a1 gene, PcAVR3a1-GI also encoded a phage integrase probably associated with the excision and integration of this mobile element. Exposure to plant induced the presence of an episomal circular intermediate of PcAVR3a1-GI, indicating that this mobile element is functional. Collectively, these findings provide evidence of PcAVR3a1 evolution via mobile elements in environmental strains of Phytophthora.

  12. Análisis de la calidad del polen en genotipos de papa Solanum tuberosum ssp. andigena y reacción a Phytophthora infestans en progenies Pollen quality analysis in Solanum tuberosum ssp. andigena and reaction to Phytophthora infestans in progenies

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    Ospina M. María Carolina

    2000-12-01

    Full Text Available En el Centro de Investigación Tibaitatá, de la Corporación Colombiana de Investigación Agropecuaria (Corpoica, localizado en el municipio de Mosquera (Cundinamarca, Colombia, con una temperatura media de 13°C y 751 mm de precipitación pluvial anual, se evaluó la viabilidad de polen en cultivares de Solanum tuberosum ssp. andigena, caracterizados por presentar resistencia a «gota» (Phytophthora infestans y precocidad. Los materiales en referencia tienen como números de origen los siguientes: 658, 678, 275, 250, 215 y 330 y como identificación los nombres: Monserrate, Lupa, Bogotana, nn, Ojona, y Manpuerra, respectivamente. De los materiales mencionados se colectó polen con el fin de evaluar su viabilidad, mediante la aplicación de los métodos de tinción morfológica y germinación in vitro, considerando para el primero como granos fértiles a aquéllos perfectamente teñidos, y, para el segundo, los que presentaron elongación del tubo polínico. En ambos métodos se realizó un conteo del número de granos viables determinando así, el porcentaje de viabilidad de polen. Con el fin de obtener semillas para evaluar la resistencia a «gota», se realizaron cruzamientos controlados entre las variedades, los cuales se distinguieron por la formación de bayas. A partir de la semilla de las progenies se obtuvieron plántulas que fueron inoculadas con el patógeno y se clasificaron dentro de las categorías de resistentes, intermedias y susceptibles. Los resultados obtenidos demostraron que las poblaciones segregantes son útiles como posibles nuevas variedades superando, a la variedad Monserrate cuya resistencia es horizontal.
    Pollen's viability in Solanum tuberosum ssp. andigena cultivars has been evaluated, mainly characterized by having late blight resistance (Phytophthora infestans and precocity. The materials were originally referenced like 658, 678, 275, 250, 215 and 330, and their identification names are: Monserrate, Lupa

  13. Efecto Antagónico in vitro de Actinomicetos Aislados de Purines de Chipaca (Bidens pilosa L. Frente a Phytophthora infestans (Mont de Bary In vitro Antagonistic Effect of Actinomycetes Isolated from Chipaca (Bidens pilosa L. Purins Against Phytophthora infestans (Mont de Bary

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    Yudy Astrid Fonseca Ardila

    2011-12-01

    Full Text Available Se estudió el efecto inhibidor de los actinomicetos presentes en purines o extractos fermentados de plantas de chipaca (Bidens pilosa L., sobre el crecimiento de Phytophthora infestans (Mont de Bary, causante del tizón tardío de la papa. Se elaboraron cuatro purines de flores, raíces, hojas-tallos y su mezcla. De estos purines se obtuvieron 25 aislamientos de actinomicetos, cada uno de los cuales se enfrentó con P. infestans en placas de medio de cultivo, utilizando la técnica de anillos de Gauze y estableciendo las concentraciones iniciales de esporas mediante conteos microscópicos en cámara de Neubauer. Los actinomicetos no crecieron en el purin de flores debido, posiblemente, a que en él no se utiliza suelo rizosférico o porque su pH (9 es mayor que el rango normal de crecimiento de estos microorganismos ( pH 6 -; 8. Se evidenció inhibición del crecimiento del oomycete por parte de 8 aislamientos de actinomicetos con porcentajes de inhibición entre 33,3 - 77,8%, provenientes de los purines de raíces, tallos-hojas y mezcla de partes de la planta. La mayor inhibición se obtuvo en los aislamientos AC001, AC010, AC011 y AC025 con conteos de 0,4, 6,0, 3,0, y 3,6 x10(5 esporas mL-1.Purins or liquid fermented extracts of chipaca (Bidens pilosa L. were prepared to establish the inhibitory effect of the actinomycetes found in such biopharmaceutical preparations on the growth of Phytophthora infestans (Mont de Bary, the causative of potato late blight disease. Four purins made from flowers, roots, leaf-steams and a mixture of them were prepared; 25 actinomycete isolates were obtained from these purins and their ability to resist challenge by P. infestans was ascertained in medium plates using the ring Gauze technique and establishing initial concentrations of spores by microscopic counting in Neubauer chamber. Actinomycetes did not grow in flower purin as rhizosphere soil was not used in its preparation or because this particular pH (9

  14. Homologous RXLR effectors from Hyaloperonospora arabidopsidis and Phytophthora sojae suppress immunity in distantly related plants

    Science.gov (United States)

    Diverse pathogens secrete effector proteins into plant cells to manipulate host cellular processes. Oomycete pathogens contain very large complements of predicted effector genes defined by an RXLR host cell entry motif. The genome of Hyaloperonospora arabidopsidis (Hpa, downy mildew of Arabidopsis) ...

  15. Study on resistance of potato with transferred avirulent genes to Phytophthora infestans%转无毒基因马铃薯抗晚疫病的研究

    Institute of Scientific and Technical Information of China (English)

    杨希才; 刘国胜; 王文慧; 田波; 居玉玲; 罗智敏

    2001-01-01

    晚疫病菌(Phytophthora infestans)引起的马铃薯晚疫病是危害全球马铃薯生产的严重病害.通过基因工程方法把外源基因导入植物体内以增强抗病性被证明是一条行之有效的途径.应用植物基因工程技术将具有能激活植物自身防御系统的无毒基因与适合于植物背景、非专一性的病原物诱导启动子组合成嵌合基因构建到植物表达载体中.通过农杆菌或基因枪的介导转化植物,可筛选出高效广谱的抗真菌和细菌病害的转基因植株.本研究从病原细菌Pseudomonas syringae PV. tomato中获得的无毒基因avrD (0*93 kb) 和从病原真菌Phytophthora parasitica中获得的无毒基因Elicitin(0.294 kb)分别与非专一性病原物诱导启动子Pill和BG组成含2个嵌合基因(Pill-avrD, BG-Elicitin)的植物表达载体pYH144和pYHEt.通过农杆菌LBA4404介导转化马铃薯,其中用pYH144载体转化2个品种(克新1号,2号),用pYHEt载体转化3个品种(Desiree,克新2号,4号),通过组织培养分别获得潮霉素(Hygromycin B)标记的转基因马铃薯试管苗.将转基因试管苗扩繁,应用马铃薯脱毒微型种薯生产技术获得转无毒基因微型薯,在温室(15~25℃和湿度高)条件下,观察转无毒基因马铃薯植株中对晚疫病菌自然感染的抗性.1998年和1999年(每年的3-5月)的温室试验初步表明:用avrD和elicitin基因分别转化的转无毒基因马铃薯植株都具有较明显的对晚疫病菌侵染的抗性,大部分转基因植株不表现或表现轻微的感病症状,对照植株(未转化)则表现明显的感病症状.转基因植株生长正常,且在感染后期(恢复期)生长良好.对照植株在恢复期生长弱和缓慢.在获得较多数量的转无毒基因马铃薯微型种薯的时候,将进行人工接种晚疫病菌和田间种植试验,从中筛选出抗真菌病和细菌病的转基因马铃薯株系.%Potato late blight caused by Phytophthora infestans is a

  16. Curdlan β-1,3-glucooligosaccharides induce the defense responses against Phytophthora infestans infection of potato (Solanum tuberosum L. cv. McCain G1) leaf cells.

    Science.gov (United States)

    Li, Jing; Zhu, Li; Lu, Guangxing; Zhan, Xiao-Bei; Lin, Chi-Chung; Zheng, Zhi-Yong

    2014-01-01

    Activation of the innate immune system before the invasion of pathogens is a promising way to improve the resistance of plant against infection while reducing the use of agricultural chemicals. Although several elicitors were used to induce the resistance of potato plant to microbial pathogen infection, the role of curdlan oligosaccharide (CurdO) has not been established. In the current study, the defense responses were investigated at biochemical and proteomic levels to elucidate the elicitation effect of CurdOs in foliar tissues of potato (Solanum tuberosum L. cv. McCain G1). The results indicate that the CurdOs exhibit activation effect on the early- and late-defense responses in potato leaves. In addition, glucopentaose was proved to be the shortest active curdlan molecule based on the accumulation of H₂O₂ and salicylic acid and the activities of phenylalanine amino-lyase, β-1,3-glucanase and chitinase. The 2D-PAGE analysis reveals that CurdOs activate the integrated response reactions in potato cells, as a number of proteins with various functions are up-regulated including disease/defense, metabolism, transcription, and cell structure. The pathogenesis assay shows that the ratio of lesion area of potato leaf decreased from 15.82%±5.44% to 7.79%±3.03% when the plants were treated with CurdOs 1 day before the infection of Phytophthora infestans. Furthermore, the results on potato yield and induction reactions indicate that the defense responses induced by CurdOs lasted for short period of time but disappeared gradually.

  17. Curdlan β-1,3-glucooligosaccharides induce the defense responses against Phytophthora infestans infection of potato (Solanum tuberosum L. cv. McCain G1 leaf cells.

    Directory of Open Access Journals (Sweden)

    Jing Li

    Full Text Available Activation of the innate immune system before the invasion of pathogens is a promising way to improve the resistance of plant against infection while reducing the use of agricultural chemicals. Although several elicitors were used to induce the resistance of potato plant to microbial pathogen infection, the role of curdlan oligosaccharide (CurdO has not been established. In the current study, the defense responses were investigated at biochemical and proteomic levels to elucidate the elicitation effect of CurdOs in foliar tissues of potato (Solanum tuberosum L. cv. McCain G1. The results indicate that the CurdOs exhibit activation effect on the early- and late-defense responses in potato leaves. In addition, glucopentaose was proved to be the shortest active curdlan molecule based on the accumulation of H₂O₂ and salicylic acid and the activities of phenylalanine amino-lyase, β-1,3-glucanase and chitinase. The 2D-PAGE analysis reveals that CurdOs activate the integrated response reactions in potato cells, as a number of proteins with various functions are up-regulated including disease/defense, metabolism, transcription, and cell structure. The pathogenesis assay shows that the ratio of lesion area of potato leaf decreased from 15.82%±5.44% to 7.79%±3.03% when the plants were treated with CurdOs 1 day before the infection of Phytophthora infestans. Furthermore, the results on potato yield and induction reactions indicate that the defense responses induced by CurdOs lasted for short period of time but disappeared gradually.

  18. Enhanced resistance to Phytophthora infestans and Alternaria solani in leaves and tubers, respectively, of potato plants with decreased activity of the plastidic ATP/ADP transporter.

    Science.gov (United States)

    Conrath, Uwe; Linke, Christoph; Jeblick, Wolfgang; Geigenberger, Peter; Quick, W Paul; Neuhaus, H Ekkehard

    2003-05-01

    Recently, it has been reported that tubers of transgenic potato ( Solanum tuberosum L.) plants with decreased activity of the plastidic ATP/ADP transporter (AATP1) contain less starch, despite having an increased glucose level [P. Geigenberger et al. (2001) Plant Physiol 125:1667-1678]. The metabolic alterations correlated with enhanced resistance to the bacterium Erwinia carotovora. Here it is shown that transgenic potato tubers, possessing less starch yet increased glucose levels due to the expression of a cytoplasm-localized yeast invertase, exhibit drastic susceptibility to E. carotovora. In addition, it is demonstrated that AATP1 anti-sense tubers show an increased capacity to ward off the pathogenic fungus Alternaria solani. In contrast to AATP1 anti-sense tubers, the corresponding leaf tissue does not show changes in carbohydrate accumulation. However, upon elicitor treatment, AATP1 anti-sense leaves possess an increased capacity to release H(2)O(2) and activate various defence-related genes, reactions that are associated with substantially delayed appearance of disease symptoms caused by Phytophthora infestans. Grafting experiments between AATP1 anti-sense plants and wild-type plants indicate the presence of a signal that is generated in AATP1 rootstocks and primes wild-type scions for potentiated activation of cellular defence responses in leaves. Together, the results suggest that (i) the enhanced pathogen tolerance of AATP1 anti-sense tubers is not due to "high sugar resistance", (ii) the increased disease resistance of AATP1 anti-sense tubers is effective against different types of pathogen and (iii) a systemic signal induced by antisensing the plastidic ATP/ADP transporter in potato tubers confers increased resistance to pathogens.

  19. Curdlan β-1,3-Glucooligosaccharides Induce the Defense Responses against Phytophthora infestans Infection of Potato (Solanum tuberosum L. cv. McCain G1) Leaf Cells

    Science.gov (United States)

    Li, Jing; Zhu, Li; Lu, Guangxing; Zhan, Xiao-Bei; Lin, Chi-Chung; Zheng, Zhi-Yong

    2014-01-01

    Activation of the innate immune system before the invasion of pathogens is a promising way to improve the resistance of plant against infection while reducing the use of agricultural chemicals. Although several elicitors were used to induce the resistance of potato plant to microbial pathogen infection, the role of curdlan oligosaccharide (CurdO) has not been established. In the current study, the defense responses were investigated at biochemical and proteomic levels to elucidate the elicitation effect of CurdOs in foliar tissues of potato (Solanum tuberosum L. cv. McCain G1). The results indicate that the CurdOs exhibit activation effect on the early- and late-defense responses in potato leaves. In addition, glucopentaose was proved to be the shortest active curdlan molecule based on the accumulation of H2O2 and salicylic acid and the activities of phenylalanine amino-lyase, β-1,3-glucanase and chitinase. The 2D-PAGE analysis reveals that CurdOs activate the integrated response reactions in potato cells, as a number of proteins with various functions are up-regulated including disease/defense, metabolism, transcription, and cell structure. The pathogenesis assay shows that the ratio of lesion area of potato leaf decreased from 15.82%±5.44% to 7.79%±3.03% when the plants were treated with CurdOs 1 day before the infection of Phytophthora infestans. Furthermore, the results on potato yield and induction reactions indicate that the defense responses induced by CurdOs lasted for short period of time but disappeared gradually. PMID:24816730

  20. RESISTENCIA AL TIZÓN TARDÍO (Phytophthora infestans EN CLONES PROMISORIOS DE PAPA EN COSTA RICA

    Directory of Open Access Journals (Sweden)

    Miguel Barquero

    2005-01-01

    Full Text Available Se determinó la resistencia al tizón tardío presente en 83 genotipos de papa, provenientes de diferentes cruces y fusión de protoplastos de líneas de mejoramiento con las especies silves- tres Solanum bulbocastanum, S. circaeifolium, S. okadae, S. laxissimum, S. berthaultii, S. pinnatisectum y S. commersonii. Los materiales fueron evaluados en el campo, y en el labora- torio se realizó pruebas de foliolos separados, utilizando como inóculo una raza compleja (1- 11 de P. infestans. Los genotipos provenientes de las hibridaciones somáticas o cruces con las especies silvestres S. bulbocastanum, S. circaei-folium y S. okadae fueron los que presentaron los valores más bajos del área bajo la curva de desarrollo de la enfermedad: 60, 80 y 79, res- pectivamente. Las variedades Alpha, Waych'a,Pimpernell y Granola, utilizadas como testigos, presentaron los valores más altos del área bajo la curva 477, 474, 466 y 427, respectivamente.

  1. Las poblaciones de Phytophthora infestans presentes en papa en el altiplano Cundiboyacense en 1996 son monomórficas para la enzima glucosa-6-fosfato Isomerasa Populations of Phytophthora infestans present on potato in the Cundinamarca and Boyacá plateau in 1996 are monomorphic for glucose-6-phosphate isomerase

    Directory of Open Access Journals (Sweden)

    Gualtero Cúellar Elsa Janeth

    1998-06-01

    Full Text Available La gota de la papa. causada por Phytophthora infestans. es responsable, en gran medida. de la disminución de la producción de este cultivo en el altiplano Cundiboyacense. Hasta el momento, el control de la gota se ha basado, principalmente, en la aplicación de fungicidas. La observación
    de una mayor variabilidad genética en las poblaciones del patógeno en varios caracteres, incluyendo la sensibilidad a fungicidas. ha mostrado la necesidad de conocer la estructura genética de las poblaciones locales: por esto se realizó una caracterización aloenzimática de las poblaciones de P infestans en Cundinamarca y Boyacá a través de glucosa-6-fosfato isomerasa (GPI lo cual permitió determinar su naturaleza clonal. En efecto todos los aislamientos locales evaluados presentaron genotipo 100/100 para GPI, es decir. fueron homocigotos monomórficos. El aislamiento Ro presentó un genotipo 86/100 que, al ser comparado
    con aislamientos de Estados Unidos, corresponde al linaje US-1. El aislamiento MT2 presentó un genotipo 84/100. Estos aislamientos corresponden a poblaciones heterocigotas que pueden ser el resultado de la reproducción sexual. El aislamiento HIN presentó un genotipo 100/100 coincidiendo con los aislamientos locales: este aislamiento es del tipo de apareamiento A1, y por comparación con aislamientos de Estados Unidos, corresponde al linaje US-6. este linaje representa una de las primeras migraciones de México a Estados Unidos, Europa y luego al resto del mundo anteriores a la migración del tipo A2. Los resultados de los análisis indicaron que las poblaciones locales no presentan diversidad, siendo por tanto de origen clonal; estos resultados están de acuerdo con la evaluación de las mismas poblaciones por  sensibilidad a metalaxil y tipo de apareamiento (González, 1997. Las poblaciones de P infestans de las localidades muestreadas en el altiplano Cundiboyacense son clonales y están constituidas por un s

  2. 黑龙江省发现马铃薯晚疫病菌(Phytophthora infestans)A2交配型%Presence of A2 Mating-type of Phytophthora infestans in Heilongjiang Province is Confirmed

    Institute of Scientific and Technical Information of China (English)

    郭梅; César Vincent; 闵凡祥; 吕军; 高云飞; 杨帅; 王晓丹; Rolot Jean-louis

    2015-01-01

    A total of 133 isolates of Phytophthora infestans col ected from Harbin, Wangkui, Mohe, Tahe, Huma, Jiagedaqi, Nenjiang, Keshan, Gannan, Hegang, Zhaodong and Linkou from 2005 to 2012 were tested for mating type. Al 51 isolates col ected from 2005 to 2010 are A1 mating type, and no A2 mating type was detected. Among the 52 isolates col ected from 2011, 12 isolates (23.08%) were A2 mating type. Among the 30 isolates tested in 2012, nine isolates (30%) were A2 mating type. No report was available about the presence of A2 mating type in Heilongjian Province until 2010 when Jiehua Zhu reported the presence of A2 mating type in 2004. This is the first report after six years of Zhu's report that confirms the A2 mating type presence in Gannan, Harbin and Zhaodong in Heilongjiang Province.%对2005~2012年间采集自黑龙江省哈尔滨、望奎、漠河、塔河、呼玛、加格达奇、嫩江、克山、甘南、鹤岗、肇东、林口12个市县的133个马铃薯晚疫病菌株进行了交配型鉴定。结果表明,采集自2005~2010年间的51个菌株均为A1交配型,未发现A2交配型;采集自2011年的52个菌株中12个为A2交配型,占23.08%;2012年鉴定的30个菌株中9个为A2交配型,占30%。这是自2004年朱杰华报道发现一株A2交配型六年后,黑龙江省首次确认在甘南、哈尔滨、肇东发现马铃薯晚疫病菌A2交配型。

  3. 致病疫霉线粒体DNA单倍型的分子鉴别%Molecular Determination on Mitochondrial DNA Haplotypes of Phytophthora infestans in Yunnan of China

    Institute of Scientific and Technical Information of China (English)

    赵志坚; RebeccaJ.Nelson; 等

    2002-01-01

    @@ 致病疫霉(Phytophthora infestans de Bary)是异宗配合的植物病原卵菌,有A1和A2两个交配型,其所引起的晚疫病是世界上最具灾害性的作物病害之一.20世纪80年代以前,除墨西哥中部被认为是致病疫霉遗传多样性起源的中心外,其它地方的致病疫霉群体几乎是单一的,一直为"旧"的无性系US-1基因型群体所统治.

  4. 甘肃马铃薯晚疫病菌对霜脲氰的敏感性测定%Sensitivity Detection of Phytophthora infestans to Cymoxanil in Gansu Province

    Institute of Scientific and Technical Information of China (English)

    吕伟; 李惠霞; 王生荣

    2010-01-01

    从2009年分离得到的马铃薯晚疫病菌(Phytophthora infestans)中随机选取15株菌株,在实验室条件下测定其对霜脲氰的敏感性,结果表明:甘肃省马铃薯晚疫病菌的菌株对霜脲氰较敏感,其EC50值为0.076 6~0.406 3μg/mL,平均EC50值为0.150 6±0.08 μg/mL,未发现抗性菌株,中间类型占86.7%,敏感菌株占13.3%.

  5. Voetsporen van evolutie: de dynamiek van effectorgenen in het Phytophthora-genoom

    NARCIS (Netherlands)

    Jiang, R.H.Y.

    2007-01-01

    Het geslacht Phytophthora omvat meer dan 65 verwoestende plantenpathogene soorten die ernstige schade toebrengen aan landbouwgewassen en aan planten, struiken en bomen in de natuur. Economisch belangrijke pathogenen zijn onder andere Phytophthora infestans, de veroorzaker van de aardappelziekte, Phy

  6. An effector of the Irish potato famine pathogen antagonizes a host autophagy cargo receptor

    Science.gov (United States)

    Dagdas, Yasin F; Belhaj, Khaoula; Maqbool, Abbas; Chaparro-Garcia, Angela; Pandey, Pooja; Petre, Benjamin; Tabassum, Nadra; Cruz-Mireles, Neftaly; Hughes, Richard K; Sklenar, Jan; Win, Joe; Menke, Frank; Findlay, Kim; Banfield, Mark J; Kamoun, Sophien; Bozkurt, Tolga O

    2016-01-01

    Plants use autophagy to safeguard against infectious diseases. However, how plant pathogens interfere with autophagy-related processes is unknown. Here, we show that PexRD54, an effector from the Irish potato famine pathogen Phytophthora infestans, binds host autophagy protein ATG8CL to stimulate autophagosome formation. PexRD54 depletes the autophagy cargo receptor Joka2 out of ATG8CL complexes and interferes with Joka2's positive effect on pathogen defense. Thus, a plant pathogen effector has evolved to antagonize a host autophagy cargo receptor to counteract host defenses. DOI: http://dx.doi.org/10.7554/eLife.10856.001 PMID:26765567

  7. Reassessment of QTLs for late blight resistance in the tomato accession L3708 using a restriction site associated DNA (RAD) linkage map and highly aggressive isolates of Phytophthora infestans.

    Science.gov (United States)

    Chen, Ai-Lin; Liu, Chu-Yin; Chen, Chien-Hua; Wang, Jaw-Fen; Liao, Yu-Chen; Chang, Chia-Hui; Tsai, Mong-Hsun; Hwu, Kae-Kang; Chen, Kai-Yi

    2014-01-01

    Tomato late blight caused by the oomycete pathogen Phytophthora infestans (Mont.) de Bary is a major threat to tomato production in cool and wet environments. Intensified outbreaks of late blight have been observed globally from the 1980s, and are associated with migration of new and more aggressive populations of P. infestans in the field. The objective of this study was to reassess late blight resistance in the wild tomato accession L3708 (Solanum pimpinellifolium L.) against pathogens of different aggressiveness. An F2:3 genetic mapping population was developed using L3708 as the paternal parent. Two isolates of P. infestans, Pi39A and Pi733, were used for inoculation. Pi733 is a highly aggressive genotype that defeats three known late blight resistance genes, Ph-1, Ph-2, and Ph-5t in tomato. In contrast, Pi39A is a less aggressive genotype that defeats only Ph-1. Restriction site Associated DNA Sequencing (RAD-Seq) technology was used to massively sequence 90 bp nucleotides adjacent to both sides of PstI restriction enzyme cutting sites in the genome for all individuals in the genetic mapping population. The RAD-seq data were used to construct a genetic linkage map containing 440 single nucleotide polymorphism markers. Quantitative trait locus (QTL) analysis identified a new disease-resistant QTL specific to Pi733 on chromosome 2. The Ph-3 gene located on chromosome 9 could be detected whichever isolates were used. This study demonstrated the feasibility and efficiency of RAD-Seq technology for conducting a QTL mapping experiment using an F2:3 mapping population, which allowed the identification of a new late blight resistant QTL in tomato.

  8. Reassessment of QTLs for Late Blight Resistance in the Tomato Accession L3708 Using a Restriction Site Associated DNA (RAD) Linkage Map and Highly Aggressive Isolates of Phytophthora infestans

    Science.gov (United States)

    Chen, Ai-Lin; Liu, Chu-Yin; Chen, Chien-Hua; Wang, Jaw-Fen; Liao, Yu-Chen; Chang, Chia-Hui; Tsai, Mong-Hsun; Hwu, Kae-Kang; Chen, Kai-Yi

    2014-01-01

    Tomato late blight caused by the oomycete pathogen Phytophthora infestans (Mont.) de Bary is a major threat to tomato production in cool and wet environments. Intensified outbreaks of late blight have been observed globally from the 1980s, and are associated with migration of new and more aggressive populations of P. infestans in the field. The objective of this study was to reassess late blight resistance in the wild tomato accession L3708 (Solanum pimpinellifolium L.) against pathogens of different aggressiveness. An F2:3 genetic mapping population was developed using L3708 as the paternal parent. Two isolates of P. infestans, Pi39A and Pi733, were used for inoculation. Pi733 is a highly aggressive genotype that defeats three known late blight resistance genes, Ph-1, Ph-2, and Ph-5t in tomato. In contrast, Pi39A is a less aggressive genotype that defeats only Ph-1. Restriction site Associated DNA Sequencing (RAD-Seq) technology was used to massively sequence 90 bp nucleotides adjacent to both sides of PstI restriction enzyme cutting sites in the genome for all individuals in the genetic mapping population. The RAD-seq data were used to construct a genetic linkage map containing 440 single nucleotide polymorphism markers. Quantitative trait locus (QTL) analysis identified a new disease-resistant QTL specific to Pi733 on chromosome 2. The Ph-3 gene located on chromosome 9 could be detected whichever isolates were used. This study demonstrated the feasibility and efficiency of RAD-Seq technology for conducting a QTL mapping experiment using an F2:3 mapping population, which allowed the identification of a new late blight resistant QTL in tomato. PMID:24788810

  9. Reassessment of QTLs for late blight resistance in the tomato accession L3708 using a restriction site associated DNA (RAD linkage map and highly aggressive isolates of Phytophthora infestans.

    Directory of Open Access Journals (Sweden)

    Ai-Lin Chen

    Full Text Available Tomato late blight caused by the oomycete pathogen Phytophthora infestans (Mont. de Bary is a major threat to tomato production in cool and wet environments. Intensified outbreaks of late blight have been observed globally from the 1980s, and are associated with migration of new and more aggressive populations of P. infestans in the field. The objective of this study was to reassess late blight resistance in the wild tomato accession L3708 (Solanum pimpinellifolium L. against pathogens of different aggressiveness. An F2:3 genetic mapping population was developed using L3708 as the paternal parent. Two isolates of P. infestans, Pi39A and Pi733, were used for inoculation. Pi733 is a highly aggressive genotype that defeats three known late blight resistance genes, Ph-1, Ph-2, and Ph-5t in tomato. In contrast, Pi39A is a less aggressive genotype that defeats only Ph-1. Restriction site Associated DNA Sequencing (RAD-Seq technology was used to massively sequence 90 bp nucleotides adjacent to both sides of PstI restriction enzyme cutting sites in the genome for all individuals in the genetic mapping population. The RAD-seq data were used to construct a genetic linkage map containing 440 single nucleotide polymorphism markers. Quantitative trait locus (QTL analysis identified a new disease-resistant QTL specific to Pi733 on chromosome 2. The Ph-3 gene located on chromosome 9 could be detected whichever isolates were used. This study demonstrated the feasibility and efficiency of RAD-Seq technology for conducting a QTL mapping experiment using an F2:3 mapping population, which allowed the identification of a new late blight resistant QTL in tomato.

  10. Comparison of Isolating and Culturing Phytophthora infestans and P.nicotianae Among Several Selective Media%几种选择性培养基对致病疫霉和烟草疫霉分离及培养比较研究

    Institute of Scientific and Technical Information of China (English)

    朱桂宁; 黄福新

    2002-01-01

    @@ 致病疫霉(Phytophthora infestans)是疫霉属真菌中一个重要的种,引起马铃薯、番茄的晚疫病,造成马铃薯、番茄生产的严重损失.近年来,晚疫病对作物的为害日益严重,引起了广大植病工作者的重视.

  11. Combined Effect of Fermentation Filtrate of Pythium oligandrurn and Chemical Pesticide Against Tomato Phytophthora infestans%寡雄腐霉发酵液与化学农药联用对番茄晚疫病菌的防治作用

    Institute of Scientific and Technical Information of China (English)

    赵建; 黄建国

    2011-01-01

    为筛选出高效安全的生物化学药剂,通过平板药效试验研究了9种常用化学农药与生防菌寡雄腐霉发酵液联合施用对番茄晚疫病的防治效果.结果表明,降低化学农药的常规施用浓度,并与寡雄腐霉发酵液联用能明显抑制番茄晚疫病菌,抑菌率可达70%;代森锰锌、百菌清和多菌灵农药与寡雄腐霉发酵液联用对寡雄腐霉菌的抑制作用较小,但能有效抑制番茄晚疫病菌,达到防治番茄晚疫病和降低农药残留的双重目的.%The antibiosis of metabolites from Pythium oligandrum hyphenated with various chemical pesticides against Phytophthora infestans was studied by using inhibitory test on plate to provide theoretical basis for screening out safe biochemical reagent with high efficiency. The results showed that combined application of lower concentration of chemical pesticides and fermentation filtrate of Pythium oligandrurn could evidently inhibit tomato Phytophthora infestans and the inhibition rate could be up to 70%. The inhibition effect of combined application of mancozeb, chlorothalonil or carbendazim with fermentation filtrate of Pythium oligandrurn on Pythium oligandrurn was very small, while effectively on tomato Phytophthora infestans, which reached double purpose of preventing and curing tomato Phytophthora infestans and reducing pesticide residues in the garden stuff.

  12. 基于无毒基因的晚疫病菌指纹类型与致病型关系研究%Correlation between pathotype and DNA fingerprinting pattern based on avirulence genes of Phytophthora infestans

    Institute of Scientific and Technical Information of China (English)

    李本金; 陈昌盛; 兰成忠; 黄灿强; 翁启勇; 陈庆河

    2011-01-01

    Four specific primers were designed according to the sequences of avirulence genes of Phytophthora infestans in GenBank and 88 P. infestans isolates from various regions were used for amplification by PCR technique with the primers. Seven types of DNA fingerprinting were obtained by assortment of the bands of PCR products. Meanwhile, pathotypes were identified with 11 different potato cultivars carrying known dominant mono-genes R1-R11 according to the response of resistance and susceptibility, the results showed that 88 isolates were separated into 4 groups at 44% genetic similarity level. There was no obvious correlation between pathotype of the pathogen and DNA fingerprinting pattern based on avirulence genes in this study.%@@ 由致病疫霉Phytophthora infestans(Mont)de Bary引起的晚疫病是马铃薯生产上可导致绝收的世界性病害,在我国各地均有发生和流行[1].传统的致病型鉴别只局限于表型上的分析,无法对复杂多变的晚疫病菌致病型变化进行快速准确的预测,因此有必要探索新的方法来弥补常规手段的不足,以便更加准确有效地监测其变化趋势.晚疫病菌与寄主马铃薯这一病理体系中的单一抗性基因和相应的无毒基因符合典型"基因对基因"学说,因此基于抗病基因与无毒基因的关系对晚疫病菌分类将更为科学和实用.到目前为止,已知的晚疫病菌无毒基因序列有Avr1、Avr2、Avr3a和Avr4[2,3].本研究试图分析晚疫病菌基于无毒基因的指纹类型与马铃薯鉴别品种划分的致病型之间是否存在对应关系,以期进一步了解病原菌群体结构特征及遗传变异本质,从而更好地指导抗晚疫病育种和品种的合理布局.

  13. Gene Silence ofPhytophthora infestans Induced by Plant-mediated RNA Inter-ference in Potato%植物介导的RNA干扰引起马铃薯晚疫病菌基因的沉默

    Institute of Scientific and Technical Information of China (English)

    任琴; 王亚军; 郭志鸿; 李继平; 谢忠奎; 王若愚; 王立; 惠娜娜

    2015-01-01

    由致病疫霉(Phytophthora infestans)引起的晚疫病是最具毁灭性的马铃薯病害。为明确植物介导的RNAi沉默致病疫霉基因的有效性,本研究采用重叠延伸PCR技术克隆同时与晚疫病菌4个ces基因均同源的融合基因C1234,构建内含子连接的C1234反向重复序列植物表达载体,采用农杆菌介导法转化晚疫病易感马铃薯品种大西洋,经PCR和Southern杂交检测,获得129个转基因株系。离体叶片接种病原菌后,有97个转基因株系发病速度明显慢于野生型,接种6 d后病斑大小和霉层厚度均明显小于对照,并且叶片感病部位没有出现失绿斑,而野生型产生了明显的失绿斑。实时定量RT-PCR分析发现,发病延缓的叶片上致病疫霉4个纤维素合酶基因的表达水平明显低于野生型。本研究表明,转基因植株中产生的以晚疫病菌ces基因为靶标的dsRNA能够沉默致病疫霉相应基因表达,延缓发病进程。%Potato late blightcaused by Phytophthora infestans is the most devastating disease in potato. The objective of this study was to test the efficiency of plant-meidated RNAi in silencing genes in P. infestans and to find a new way to breed potato resistant to late blight. Over-lap PCR was employed to amplify a fused-geneC1234 simultaneously homologous to four cellulose synthase genes inP. infenstans. Then, a plant expression vector containing inverted repeat ofC1234was constructed and transferred to Atlantic, a potato variety severely susceptible to late blight by agrobacteria-mediated genetic transformation. A hundred and twenty nine regenerated lines were confirmed to be transgenic plants with PCR and Southern blot. When detached leaves were inoculated withP. infestans, 97 out of 129 transgenic lines delayed disease symptoms with smaller lesions and less hyphae com-pared to the wild type at six days after inoculation. Chlorotic spots did not appeared on leaves from transgenic lines while deve

  14. Targeted gene mutation in Phytophthora spp.

    NARCIS (Netherlands)

    Lamour, K.H.; Finley, L.; Hurtado-Gonzales, O.; Gobena, D.; Tierney, M.; Meijer, H.J.G.

    2006-01-01

    The genus Phytophthora belongs to the oomycetes and is composed of plant pathogens. Currently, there are no strategies to mutate specific genes for members of this genus. Whole genome sequences are available or being prepared for Phytophthora sojae, P. ramorum, P. infestans, and P. capsici and the d

  15. 植物内生真菌镰刀菌对马铃薯晚疫病菌的抑制研究%Inhibition Effect of Plant Endophytic Fusarium spp. on Phytophthora infestans

    Institute of Scientific and Technical Information of China (English)

    苏珍珠; 罗文富; 杨艳丽; 杨子祥

    2009-01-01

    鉴定了分离自7种植物上的11株内生真菌镰刀菌并研究了它们对马铃薯晚疫病菌的抑菌活性.对峙培养试验表明:11株内生真菌镰刀菌对该病菌均有抑制作用,其中菌株e060-1, e060-3,e060-4的抑制率达50%以上.这些内生真菌镰刀菌的毒素粗提液对该病菌菌丝生长有更明显的抑制作用,其中e012-3,e060-4和e032毒素粗提液的抑菌率达100%.毒素粗提液能明显抑制晚疫病菌孢子对离体叶片的侵染,其中菌株e032毒素粗提液的抑制率达97.1%.%Eleven strains of endophytic Fusarium spp. isolated from 7 kinds of healthy plants were identified.And the inhibitory activities of these endophytic Fusarium spp. against Phytophthora infestans were tested.All these strains showed a certain degree inhibitory effects on the hypha growth of P. infestans by dual culture. The inhibition rates of strains e060-1,e060-3 and e060-4 were above 50%.The inhibitory effects of unrefined toxin extracts obtained from endophytic Fusarium spp. were more significant against hypha growth of P. infestans. The inhibitory rates of unrefined toxin extracts of e012-3, e060-4 and e032 were up to 100%. The unrefined toxin extracts of endophytic Fusarium also inhibited the infection of P. infestans spore to detached leaves. The unrefined toxin extract of strain e032 had the best inhibitory effects at the inhibitory rate of 97.1%.

  16. Carbohydrate-related enzymes of important Phytophthora plant pathogens.

    Science.gov (United States)

    Brouwer, Henk; Coutinho, Pedro M; Henrissat, Bernard; de Vries, Ronald P

    2014-11-01

    Carbohydrate-Active enZymes (CAZymes) form particularly interesting targets to study in plant pathogens. Despite the fact that many CAZymes are pathogenicity factors, oomycete CAZymes have received significantly less attention than effectors in the literature. Here we present an analysis of the CAZymes present in the Phytophthora infestans, Ph. ramorum, Ph. sojae and Pythium ultimum genomes compared to growth of these species on a range of different carbon sources. Growth on these carbon sources indicates that the size of enzyme families involved in degradation of cell-wall related substrates like cellulose, xylan and pectin is not always a good predictor of growth on these substrates. While a capacity to degrade xylan and cellulose exists the products are not fully saccharified and used as a carbon source. The Phytophthora genomes encode larger CAZyme sets when compared to Py. ultimum, and encode putative cutinases, GH12 xyloglucanases and GH10 xylanases that are missing in the Py. ultimum genome. Phytophthora spp. also encode a larger number of enzyme families and genes involved in pectin degradation. No loss or gain of complete enzyme families was found between the Phytophthora genomes, but there are some marked differences in the size of some enzyme families.

  17. The genus Phytophthora anno 2012.

    Science.gov (United States)

    Kroon, Laurens P N M; Brouwer, Henk; de Cock, Arthur W A M; Govers, Francine

    2012-04-01

    Plant diseases caused by Phytophthora species will remain an ever increasing threat to agriculture and natural ecosystems. Phytophthora literally means plant destroyer, a name coined in the 19th century by Anton de Bary when he investigated the potato disease that set the stage for the Great Irish Famine. Phytophthora infestans, the causal agent of potato late blight, was the first species in a genus that at present has over 100 recognized members. In the last decade, the number of recognized Phytophthora species has nearly doubled and new species are added almost on a monthly basis. Here we present an overview of the 10 clades that are currently distinguished within the genus Phytophthora with special emphasis on new species that have been described since 1996 when Erwin and Ribeiro published the valuable monograph 'Phytophthora diseases worldwide' (35).

  18. Phytophthora infestans in the USA

    Science.gov (United States)

    This book chapter is specific to late blight in the United States and will include a review and discussion of the history of late blight on potato and tomato crops, changes in grower attitudes towards late blight, present status of the disease in the US, methods for identification, management, and c...

  19. The Activation of Phytophthora Effector Avr3b by Plant Cyclophilin is Required for the Nudix Hydrolase Activity of Avr3b.

    Science.gov (United States)

    Kong, Guanghui; Zhao, Yao; Jing, Maofeng; Huang, Jie; Yang, Jin; Xia, Yeqiang; Kong, Liang; Ye, Wenwu; Xiong, Qin; Qiao, Yongli; Dong, Suomeng; Ma, Wenbo; Wang, Yuanchao

    2015-08-01

    Plant pathogens secrete an arsenal of effector proteins to impair host immunity. Some effectors possess enzymatic activities that can modify their host targets. Previously, we demonstrated that a Phytophthora sojae RXLR effector Avr3b acts as a Nudix hydrolase when expressed in planta; and this enzymatic activity is required for full virulence of P. sojae strain P6497 in soybean (Glycine max). Interestingly, recombinant Avr3b produced by E. coli does not have the hydrolase activity unless it was incubated with plant protein extracts. Here, we report the activation of Avr3b by a prolyl-peptidyl isomerase (PPIase), cyclophilin, in plant cells. Avr3b directly interacts with soybean cyclophilin GmCYP1, which activates the hydrolase activity of Avr3b in a PPIase activity-dependent manner. Avr3b contains a putative Glycine-Proline (GP) motif; which is known to confer cyclophilin-binding in other protein substrates. Substitution of the Proline (P132) in the putative GP motif impaired the interaction of Avr3b with GmCYP1; as a result, the mutant Avr3bP132A can no longer be activated by GmCYP1, and is also unable to promote Phytophthora infection. Avr3b elicits hypersensitive response (HR) in soybean cultivars producing the resistance protein Rps3b, but Avr3bP132A lost its ability to trigger HR. Furthermore, silencing of GmCYP1 rendered reduced cell death triggered by Avr3b, suggesting that GmCYP1-mediated Avr3b maturation is also required for Rps3b recognition. Finally, cyclophilins of Nicotiana benthamiana can also interact with Avr3b and activate its enzymatic activity. Overall, our results demonstrate that cyclophilin is a "helper" that activates the enzymatic activity of Avr3b after it is delivered into plant cells; as such, cyclophilin is required for the avirulence and virulence functions of Avr3b.

  20. Genetic structure and pathogenicity of populations of Phytophthora infestans from organic potato crops in France, Norway, Switzerland and the United Kingdom

    NARCIS (Netherlands)

    Flier, W.G.; Kroon, L.P.N.M.; Hermansen, A.; Raaij, van H.M.G.; Speiser, B.; Tamm, L.; Fuchs, J.G.; Lambion, J.; Razzaghian, J.; Andrivon, D.; Wilcockson, S.; Leifert, C.

    2007-01-01

    Genetic variation and pathogenicity of Pbytophthora infestans isolates collected from organic potato crops of the susceptible cv. Bintje and the moderately resistant cv. Sante were assessed in France, Norway, and the United Kingdom in 2001 and in Switzerland in 2001 and 2002. Population structures d

  1. 10种杀菌剂对番茄晚疫病菌的室内毒力测定%Toxicity Test of Ten Fungicides to Phytophthora infestans in Laboratory

    Institute of Scientific and Technical Information of China (English)

    张成玲; 张田田; 路兴涛; 张勇; 刘震; 马士仲

    2012-01-01

    采用菌丝生长抑制法测定了烯酰吗啉、嘧霉胺等10种杀菌剂对番茄晚疫病菌(Phytophthora infestans)的室内活性.结果表明:50%烯酰吗啉可湿性粉剂防效最高,EC50和EC90值分别为1.81 μg/ml和10.63 μg/ml,回归方程为Y=4.57272+ 1.66462X;其次是250 g/L嘧菌酯悬浮剂和75%百菌清可湿性粉剂,EC50和EC90值分别为2.70、2.54μg/ml和1.08 ×107、10708.95μg/ml,但两种药剂随着浓度的增加防效增加不显著,EC90的值都较高;58%甲霜·锰锌可湿性粉剂和70%代森联水分散粒剂的防效相对较高,EC50低于10 μg/ml,分别为6.09、8.75 μg/ml,EC90分别为69.98、60.19 μg/ml,回归方程分别为Y=4.05225+ 1.20831X和Y =3.55894+ 1.52997X.25%多菌灵可湿性粉剂对病原菌菌丝也有抑制作用,各个处理菌丝扩展面积大,但茵丝生长稀薄,长势弱.%The toxicity of 10 fungicides against Phytophthora infestans was detected by the method of mycelium growth inhibition. The results showed that 50% dimethomorph WP had the best control effect with EC50 and EC90 as 1.81 μg/ml and 10.63 μg/ml respectively, and the regression equation was Y = 4.57272 + 1.66462X. The Mowed fungicides were 250 g/L azoxystrobin SC and 75% chlorothalonil WP with the EC50 as 2.70μg/ml and 2.54μg/ml, and the EC90 as 1.08 x 107 μg/ml and 10 708.95 fig/ml respectively. But with the increase of dosage, the control effects of the two fungicides did not increase significantly, and their EC90 value were higher. The control effects of 58% metalaxyl · mancozeb WP and 70% metiram WDP were relatively higher with the EC90 value as 6.09 μg/ml and 8. 75 μg/ml, and the EC90 as 69. 98 μg/ml and 60.19 μg/ml respectively. Their regression equations were Y =4. 05225 + 1. 20831X and Y = 3. 55894 + 1.52997X respectively. 25% carbendazim WP also could inhibit Phytophthora infestans. Although the extended area of hypha was great, the hypha grew weak and thin.

  2. 云南省马铃薯晚疫病菌交配型及生物学特性研究(英文)%MATING TYPE AND BIOLOGICAL CHARACTERISTICS OF Phytophthora infestans ISOLATES FROM YUNNAN, CHINA

    Institute of Scientific and Technical Information of China (English)

    国立耘; 杨艳丽; 罗文富

    2002-01-01

    作者对1998~2000年间采自云南省13个县、23个地点的马铃薯晚疫病菌的交配型、菌落形态、燕麦培养基上生长情况、生长速度和产孢量进行了测定.结果显示,采自云南13个县、23个地点的共157个菌株全部为A1交配型,表明云南马铃薯主产区的晚疫病菌以A1交配型为主,同时,被测的代表菌株在生长速度和产孢量上存在显著差异,表明这一地区的晚疫病菌种群内存在丰富的遗传多样性.此外,结果还显示,晚疫病菌菌株在燕麦培养基上的生长情况与其菌落形态和交配型不相关.%Phytophthora infestans from potatoes collected from Yunnan Province during 1998 to 2000 were investigated for their mating type, colony growth pattern, ability to grow on oatmeal agar, linear growth rate and amount of sporangia produced. A total of 157 isolates from 23 locations in 13 counties in Yunnan were all A1 mating type. Representative isolates showed significant variation in growth rate and amount of sporangia produced, which indicate the existence of genetic diversity among the population of P. infestans in Yunnan. Results also show that colony growth pattern and the growth on oatmeal agar did not relate to the mating type of the isolate.

  3. Mitochondrial genomics in the Genus Phytophthora with a focus on Phytophthora ramorum

    Science.gov (United States)

    Frank N. Martin; Paul Richardson

    2008-01-01

    The mitochondrial genomes of Phytophthora infestans, P. ramorum and P. sojae have been sequenced and comparative genomics has provided an opportunity to examine the processes involved with genome evolution in the genus Phytophthora. This approach can also be useful in assessing intraspecific...

  4. 致病疫霉拮抗细菌的筛选及抑菌作用研究%Screening of Antagonistic Bacterial Strain against Phytophthora infestans and Its Inhibition Effect

    Institute of Scientific and Technical Information of China (English)

    李丽艳; 蒋继志; 郭文

    2011-01-01

    [Objective] The paper was to screen bacterial strain with significant antagonistic effect against Phytophthora infestans, so as to provide basis for further development and utilization of antagonistic bacteria to control P. infestans and potato late bright. [ Method] Plant confrontation and filter paper method was used to determine the inhibition effect of living, fermentation product, and bacterial fluid of 61 strains a-gainst P. infestans and the induced resistance of SR13-2 strain. [Result] The inhibition rate of 24 strains among 61 tested strains against my-celial growth of P. infestans was greater than 60% , and the inhibition effect of HT-6 strain was the strongest with the inhibition rate of 89.92%. However, fermentation product of all tested strains had no significant inhibition effect on P. infestans, while the inhibition effect of bacterial fluid of most strains was significantly higher than living strain; the inhibition effect of S34-1 strain was the strongest with inhibition rate of 91.50%. The bacterial fluid of SR13-2 strain was found to have significant resistance-induction effect with protection rate of 60%. [Conclusion] The inhibition effect of living and fermentation product of antagonistic strains S34-1 and SR13-2 had no relationship with each other, while bacterial fluid had great potential in controlling potato late bright.%[目的]筛选获得显著拮抗致病疫霉的细菌菌株,为深入开发利用拮抗细菌抑制致病疫霉并控制马铃薯晚疫病提供依据.[方法]用平板对峙法和滤纸片法测定61株细菌活体、发酵液及茵液对致病疫霉的抑制作用并进一步测定了SR13-2菌株的诱导抗病作用.[结果]供试的61株细菌活体对致病疫霉菌丝生长的抑制率达到60%以上的有24株,其中HT-6菌株的抑茵作用最强,抑茵率达到了89.92%:但所有供试菌株的发酵液均无显著抑菌作用,而大部分菌株茵液的抑茵作用却明显高于活体菌株,其中以S34-1菌

  5. The nature of biotrophy in Phytophtora infestans

    NARCIS (Netherlands)

    Scheepens, P.C.

    1978-01-01

    Phytophthora infestans, being an intermediate type between the facultative and obligate parasites among the Peronosporales (class Oomycetes ), was used to study the factors which are responsible for the inability of obligate parasites to grow axenically. In a comparative study on mitochondrial elec

  6. Differences in intensity and specificity of hypersensitive response induction in Nicotiana spp. by INF1, INF2A, and INF2B of Phytophthora infestans

    NARCIS (Netherlands)

    Huitema, E.; Vleeshouwers, V.G.A.A.; Cakir, C.; Kamoun, S.; Govers, F.

    2005-01-01

    Elicitins form a family of structurally related proteins that induce the hypersensitive response (HR) in plants, particularly Nicotiana spp. The elicitin family is composed of several classes. Most species of the plant-pathogenic oomycete genus Phytophthora produce the well-characterized 10-kDa

  7. 菊花提取物对番茄晚疫病菌抑制效果的研究%Inhibitory Efficacy of Dendronthema orifolium (Ramat)Tzvel Extracts on the Phytophthora infestans

    Institute of Scientific and Technical Information of China (English)

    曹静; 段英姿; 马艳芝

    2009-01-01

    在室内以甲霜灵为化学对照,80%乙醇为空白对照测试了菊花乙醇提取物对番茄晚疫病菌(Phytophthora infestans)菌丝生长和孢子囊萌发的抑制作用,以及光照、温度对菊花提取物抑菌效果的影响.结果表明:菊花的乙醇提取物抑制番茄晚疫病菌菌丝生长的有效中浓度为稀释470倍,抑制孢子囊萌发的有效中浓度为稀释1 055倍;光照强度在6 000~80 000 lx范围内,温度在40~90℃范围内,菊花提取物的抑菌效果和化学药剂甲霜灵差异不显著.

  8. 致病疫霉在中国云南的马铃薯田间形成卵孢子%FORMATION OF OOSPORES OF PHYTOPHTHORA INFESTANS IN NATURAL POTATO FIELD IN YUNNAN PROVINCE OF CHINA

    Institute of Scientific and Technical Information of China (English)

    赵志坚; 李成云; 王淑芬; 隋启君

    2001-01-01

    @@ 由致病疫霉Phytophthora infestans (Mont.)de Bary引起的马铃薯和番茄晚疫病是世界性的作物病害,每年均造成巨大的经济损失和社会影响.致病疫霉是异宗配合的卵菌,有两个已知交配型A1和A2,两个相对交配型互作时可进行有性生殖产生卵孢子(Gallegly & Galindo,1958).过去许多年一直认为致病疫霉在除墨西哥以外的国家中只存在A1交配型,通过产生孢子囊进行无性繁殖.近年来,由于致病疫霉新致病群体的产生以及全球范围的迁移和替代,A2交配型菌株先后在欧洲、美洲、亚洲和非洲的许多国家被发现.

  9. 致病疫霉对苯酰胺类杀菌剂抗性研究概述%Review of Resistance to Phenylamide Fungicide in Phytophthora infestans Isolates

    Institute of Scientific and Technical Information of China (English)

    杨宇红; 冯兰香; 谢丙炎; 冯东昕

    2002-01-01

    @@ 致病疫霉(Phytophthora infestans)引起的马铃薯和番茄晚疫病是一种世界性的重要病害,该病造成的损失及用于防治的费用使晚疫病成为世界上耗资最大的病害之一[1].1995年,美国哥伦比亚盆地和俄勒冈州,因马铃薯晚疫病造成的损失及用于防治的费用高达3 000万美元;1998年,通过改进栽培管理,其经济损失和防治费用有所降低,但仍达2 230万美元,其中杀菌剂费用占去1 980万美元[2].由此可见杀菌剂在晚疫病的防治中依然起着不可替代的作用.

  10. 致病疫霉拮抗菌梨黑斑病菌发酵条件的优化%Optimization of fermentation conditions of Alternaria kikuchiana against the growth of Phytophthora infestans

    Institute of Scientific and Technical Information of China (English)

    刘海珍; 蒋继志; 王会仙

    2010-01-01

    为提高梨黑斑病菌(Alternaria kikuchiana)102菌株发酵产物对致病疫霉(Phytophthora infestans)Z182菌株生长的抑制效率,本研究利用涂布法和滤纸片法、采用单因素试验设计方法.在静置培养条件下,对梨黑斑病菌的最佳发酵条件进行了优化.结果显示,该菌株在28℃、自然pH、80 ml,/250 mL装液量、6%接种量、黑暗培养8 d,所得发酵液对致病疫霉有较强的抑制作用,抑菌率可达85.7%.该菌株的抑制率优化后比优化前高出约15%,表明利用该菌株在抑制致病疫霉生长方面有进一步研究和利用的潜力.

  11. 马铃薯致病疫霉EST-SSR PCR反应体系的优化%Optimization of PCR system in EST-SSR analysis of Phytophthora infestans

    Institute of Scientific and Technical Information of China (English)

    王佳楠; 吕文河; 金光辉; 白雅梅; 李文霞; 韩英鹏

    2009-01-01

    由致病疫霉(Phytophthora infestans Montagne de Bary)引起的马铃薯晚疫病是危害马铃薯生产的最严重病害.试验以致病疫霉茵株HHO6-23为模板,以Pi08N为引物,研究致病疫霉EST-SSR PCR反应体系中各主要成分和退火温度对扩增结果的影响.优化后的PCR反应体系为:25 ng模板DNA,0.5 mmol·L-1dNTPs,2μL10×Buffer(Mg2+Free),1.75 mmol·L-1MgCl2,15 pmol引物,1.2 UTaq DNA聚合酶,加ddH2O至20μL;同时确定引物退火温度为63℃.PCR体系稳定性试验结果表明,优化后的致病疫霉EST-SSR PCR反应体系稳定、可靠,适合进行致病疫霉群体遗传多样性研究.

  12. Evaluación de la reacción de nueve genotipos de papa (Solanum tuberosumsubsp. andigena al ataque de Phytophthora infestans (Mont de Bary

    Directory of Open Access Journals (Sweden)

    Betancourth G. Carlos

    2008-12-01

    Full Text Available

    El presente trabajo se realizó en el municipio de Pasto, departamento de Nariño, Colombia, a 2.710 msnm. El objetivo fue evaluar la reacción de los clones de papa Blanca, Pintada, Rosada tipo Capiro, Roja Guata, Roja Redonda y Roja Loca y tres variedades mejoradas: Parda Suprema, Roja Nariño y Betina, al ataque de la gota (Phytophthora infestans. Se utilizó un diseño de bloques al azar con cuatro repeticiones y nueve tratamientos. Para la variable severidad los mejores genotipos fueron Blanca, Pintada, Parda Suprema y Betina con un promedio de 19,72; 21,99; 23,15 y 23,62%, respectivamente. El mejor rendimiento fue obtenido por los genotipos Blanca, Pintada, Parda Suprema, Betina y Roja Loca con 29,61; 24,66; 25,71; 27,12 y 28,05 t•ha-1, en su orden.

  13. Evaluation of the Heritability of Resistance to Phytophthora infestans (Mont de Bary in a Population of Solanum phureja Juz et Buk / Evaluación de la Heredabilidad de la Resistencia a Phytophthora infestans (Mont de Bary en una Población de Solanum phu

    Directory of Open Access Journals (Sweden)

    Orozco Orozco Luz Fanny

    2013-08-01

    Full Text Available Potato late blight is a common name for the mostimportant and destructive disease caused by Phytophthorainfestans (Mont. de Bary in potato crops. Resistance genesfor the disease have been found in Solanum phureja, and areof great importance in implementing important tools such asplant breeding in disease management The aim of this studywas to estimate the heritability of resistance to P. infestansin a population of S. phureja. This research was carried outin potato cultivations in two locations in the municipality of LaUnión (Antioquia, Colombia. Pathogen severity was evaluatedin leaves using a diagrammatic scale. Heritability was measured between families and within families by stratified mass and simple mass selection. There were no statistically significant differences among the heritabilities from the methods of selection; however, significant differences were found between locations. For the first location, heritability estimations were in the range of 0.35 and 0.54, while values obtained in the second location were between 0.05 and 0.08. / El tizón tardío o gota de la papa producido porPhytophthora infestans (Mont. de Bary, es la enfermedadmás limitante del cultivo. El mejoramiento genético, conla obtención de variedades resistentes es un componenteimportante del manejo integrado del patógeno; en la especieSolanum phureja se han encontrado genes de resistencia a laenfermedad. La heredabilidad permite estimar la proporción de la variabilidad total debida al efecto de los genes; y esta depende de la población en estudio y de la unidad de selección que se utilice. El objetivo de este estudio fue estimar la heredabilidad de la resistencia a la gota de la papa en una población de S. phureja. Esta investigación, se desarrolló en dos localidades del municipio de La Unión (Antioquia, Colombia, en la cual se evaluó la severidad de la enfermedad utilizando una escala diagramática de severidad para hoja. La heredabilidad se evalu

  14. Parasitic fitness of Phytophthora infestans isolated from southern regions of Ningxia%宁夏南部山区马铃薯晚疫病菌寄生适合度测定

    Institute of Scientific and Technical Information of China (English)

    郭成瑾; 张丽荣; 沈瑞清

    2012-01-01

    为了解宁夏南部山区马铃薯主栽品种对马铃薯晚疫病菌的抗病性情况,明确不同菌株的寄生适合度,采用离体叶片接种法,用4个马铃薯品种对采自宁夏南部山区的5个马铃薯晚疫病菌分离株进行了侵染率、病斑面积、产孢能力的测定和寄生适合度的计算.结果表明,‘克新18号’对供试的晚疫病菌分离株具有较高的抗病性,其次为‘中薯3号’和‘克新1号’,‘费乌瑞它’的抗病性最差;来源于固原原州区的分离株(GL2和GL7)寄生适合度较高,来源于泾源县的分离株(JZ)寄生适合度较弱.采自宁夏不同地区的晚疫病菌分离株对同一马铃薯品种的寄生适合度有较大差异,同一晚疫病菌株在不同马铃薯品种上的寄生适合度也有一定的差异,表明宁夏南部山区马铃薯晚疫病菌分离株存在一定的致病性分化.%In order to understand the main potato cultivars resistance to Phytophthora infestans and the parasitic fitness of different causal fungal isolates, the infection frequency, lesion size, and sporulation capacity of five P. infestans isolates from potato in the southern regions of Ningxia were tested using four potato cultivars on the detached leaflets. The results showed that the cultivar 'Kexin 18' had the strongest resistance to the tested isolates, and 'Zhongshu 3' and 'Kexin 1' took the second place, while 'Favorita' was the susceptible cultivar to the tested isolates. The result of calculated parasitic fitness revealed that the isolate GL2 and GL7 from Yuanzhou District of Guyuan City had the highest parasitic fitness, and the isolate JZ from Jingyuan County had the lowest fitness. In summary, the tested P. infestans isolates from southern regions of Ningxia had different parasitic fitness on the same cultivar, and the single isolate has different parasitic fitness on the same cultivar, indicating that the pathogenic differentiation exists to some degree among P. infestans

  15. Seleccion de híbridos de especies de papa por resistencia a phytophthora infestans (mont) de bary, fertilidad masculina y potencial productivo

    OpenAIRE

    Ñustez L., Carlos Eduardo; Estrada Ramos, Nelson; Mártinez Becerra, Ricardo

    2011-01-01

    En la Universidad Nacional de Colombia en Mosquera durante los años 1988 y 1989 se realizó una investigación, donde se evaluó bajo condiciones de invernadero la resistencia a P. infestans de las progenies de 51 cruzamientos (F1 y avanzados). que inclu ían en su pedigree especies silvestres,primitivas y/o cultivadas de papa. Luego de un primer ciclo de selección los genotipos escogidos se evaluaron en campo porresistencia a la enfermedad, fertilidad masculina y potencial productivo (kg/planta)...

  16. Toxicity Test of Six Fungicides in vitro to Phytophthora infestans from Potatoes%6种杀菌剂对马铃薯晚疫病菌的室内毒力测定

    Institute of Scientific and Technical Information of China (English)

    田琴; 杨志辉; 朱杰华

    2012-01-01

    The toxiciUes of six fungicides(Mandipropamid, Famoxadone .cymoxanil, Fluopicolide .propamocab hydro chloride, Dimethomorph@ copper abietate, Propineb @ cymoxanil and Mancozeb) to Phytophthora infestans were determined by the method of growth rate in vitro. These tested fungicides had a better inhibiting effect on mycelial growth of P. infestans, of which Mandipropamid was the best one, with EC50 value being 0.029 μg/mL, followed by Famoxadone.cymoxanil, Propineb. cymoxanil, Dimethomorph .copper abietate, Fluopicolide .propamocab hydrochloride and the worst one was Mancozeb, whose EC50 value was 5.502 μg / mL. Based on the toxicity estimation in vitro and their characteristics, the six tested fungicides could be alternately and reasonably used to control the potato late blight in order to avoid or delay the occurrence of fungicide resistance in potato production.%试验采用生长速率法测定了双炔酰菌胺、恶酮.霜脲氰、氟菌.霜霉威、烯酰.松脂酮、丙森锌.霜脲氰、代森锰锌6种杀菌剂对马铃薯晚疫病菌的毒力。结果表明,供试6种杀菌剂对马铃薯晚疫病菌丝生长都有良好的抑制效果。双炔酰菌胺的毒力最强,其EC50值为0.029μg/mL,恶酮.霜脲氰、丙森锌.霜脲氰、烯酰.松脂酮、氟菌.霜霉威毒力依次减弱,而代森锰锌毒力最差,其EC50值为5.502μg/mL。根据室内毒力测定结果及药剂特性,供试的6种杀菌剂在田间防治上可视病害的发生情况交替或混合应用,做到科学合理搭配,以避免或延缓抗药性的产生。

  17. The aspartic proteinase family of three Phytophthora species

    NARCIS (Netherlands)

    Kay, J.; Meijer, H.J.G.; Have, ten A.; Kan, van J.A.L.

    2011-01-01

    Background - Phytophthora species are oomycete plant pathogens with such major social and economic impact that genome sequences have been determined for Phytophthora infestans, P. sojae and P. ramorum. Pepsin-like aspartic proteinases (APs) are produced in a wide variety of species (from bacteria to

  18. Genomic Analyses of Dominant U.S. Clonal Lineages of Phytophthora infestans Reveals a Shared Common Ancestry for Clonal Lineages US11 and US18 and a Lack of Recently Shared Ancestry Among All Other U.S. Lineages.

    Science.gov (United States)

    Knaus, B J; Tabima, J F; Davis, C E; Judelson, H S; Grünwald, N J

    2016-11-01

    Populations of the potato and tomato late-blight pathogen Phytophthora infestans are well known for emerging as novel clonal lineages. These successions of dominant clones have historically been named US1 through US24, in order of appearance, since their first characterization using molecular markers. Hypothetically, these lineages can emerge through divergence from other U.S. lineages, recombination among lineages, or as novel, independent lineages originating outside the United States. We tested for the presence of phylogenetic relationships among U.S. lineages using a population of 31 whole-genome sequences, including dominant U.S. clonal lineages as well as available samples from global populations. We analyzed ancestry of the whole mitochondrial genome and samples of nuclear loci, including supercontigs 1.1 and 1.5 as well as several previously characterized coding regions. We found support for a shared ancestry among lineages US11 and US18 from the mitochondrial genome as well as from one nuclear haplotype on each supercontig analyzed. The other nuclear haplotype from each sample assorted independently, indicating an independent ancestry. We found no support for emergence of any other of the U.S. lineages from a common ancestor shared with the other U.S. lineages. Each of the U.S. clonal lineages fit a model where populations of new clonal lineages emerge via migration from a source population that is sexual in nature and potentially located in central Mexico or elsewhere. This work provides novel insights into patterns of emergence of clonal lineages in plant pathogen genomes.

  19. Sensitivity of Metalaxyl-Resistant Strains of Phytophthora infestans to Five Fungicides%抗甲霜灵致病疫霉菌对5种杀菌剂的敏感性测定

    Institute of Scientific and Technical Information of China (English)

    兰成忠; 陈庆河; 李本金; 赵健; 翁启勇

    2011-01-01

    In order to determine the sensitivity of metalaxyl-resistant strains of Phytophthora infestans to fungicides flumorph, azoxystrobin, pyraclostrobin, dimethomorph and cymoxanil, the toxicity of fungicides to metalaxylsensitive and metalaxyl-resistant strains of P. Infestans were tested by measuring radial growth on agar medium amended with fungicides. The results showed that the five tested fungicides had high inhibitory activity against mycelium growth and sporangia formation of metalaxyl-resistant and metalaxyl-sensitive isolates of P. Infestans. Flumorph exhibited the strongest toxicity to metalaxyl-resistant strains with the mean EC50 of 0. 037 6 μg · mL-1. There was obvious difference in sensitivity of tested isolates to cymoxanil, which ECM values ranged from 0. 008 4 μg · mL-1 to 0. 868 1 μg · mL-1 , the mean EC50 value was 0. 386 6 μg · mL-1 in inhibiting the mycelium growth of metalaxyl-resistant strains. There is high correlation of tested results between in vitro method and the floating-leaf-disk method, and showed that the tested fungicides had no cross-resistance with metalaxyl. These fungicides maybe substitute metalaxyl for controlling potato and tomato late blight disease.%为明确致病疫霉菌甲霜灵抗性菌株对氟吗啉、嘧菌酯、吡唑醚菌酯、烯酰吗啉和霜脲氰的敏感性,采用菌丝生长速度法,并用叶盘漂浮法加以比较,测定了致病疫霉菌甲霜灵抗性菌株和敏感性菌株对供试杀菌剂的敏感性.试验结果表明,供试5种杀菌剂对致病疫霉菌甲霜灵抗性和敏感菌株的菌丝生长、孢子囊的形成都具有明显的抑制作用.对致病疫霉菌甲霜灵抗性菌株毒力最强的杀菌剂是氟吗啉,其平均EC50值为0.037 6μg·mL-1,致病疫霉菌间对霜脲氰的敏感性差异显著,EC50值在0.008 4~0.868 1μg·mL-1之间,其中甲霜灵抗性菌株平均EC50值为0.386 6 μg·mL-1.菌丝生长速率法离体测定表现出与叶盘漂浮法结果具有较

  20. Inhibitory efficacy of several plant extracts and plant products on Phytophthora infestans%几种植物提取物和天然产物对马铃薯晚疫病菌的抑制作用

    Institute of Scientific and Technical Information of China (English)

    曹克强; ArienaHCvanBruggen

    2001-01-01

    The effects of garlic and scouring rush extracts and two plant products-Bio-clean and Citronella Oil, on spore germination, hyphae growth and infection of Phytophthora infestans (Mont.) de Bary on potato leaves were evaluated and measured in comparison with protective fungicide chlorothalonil and distilled water which was used as control. Highest inhibitions on germination of P. infestans were obtained with Bio-clean and garlic (Allium sativum L.). The inhibition rates on germination of sporangia and zoospores increased with increasing concentrations of these extracts and reached as high as 100 percent when the dosages were high. The germination of zoospores was totally stopped by all the concentrations of Bio-clean and garlic. Scouring rush also showed antifungal properties but with less extent. Citronella oil didn't show effectiveness on inhibiting sporangium germination but reduced the germination rate of zoospores. Garlic extracts from fresh bulbs had stronger inhibiting effect than the extract from dry garlic bulbs on the germination of sporangia and zoospores. However, there was no significant difference between the extracts of immediately made from fresh bulbs and those which was kept for a week under 4℃. The effect of scouring rush extract from fresh leaves was not significantly superior over the extract from dry leaves and the extract from fresh leaves but stored for one week on inhibiting sporangium germination. However, the inhibiting effects against zoospore germination were significantly different between the extracts from fresh leaves and that from dry leaves. Tests were made on inhibiting effects of plant extracts and plant products on hyphae growth of P. infestans on petri dishes. No mater autoclaved or not, Bio-clean 0.125% totally inhibited the formations of P. infestans colonies, which indicated that Bio-clean is not sensitive to heat. The inhibiting effect of garlic was as good as Bio-clean when it was not autoclaved. However, its effect lost

  1. β(1,3 GLUCANASAS DE LOS ESPACIOS INTERCELULARES DE HOJAS DE TOMATE LYCOPERSICON ESCULENTUM CERACIFORME DESPUES DE INFECCIÓN CON PHYTOPHTHORA INFESTANS.

    Directory of Open Access Journals (Sweden)

    Humberto M. Zamora

    2009-06-01

    Full Text Available Análisis en líquido de lavado intercelular de Lycopersicon esculentum ceraciforme L1568 perteneciente al germoplasma nacional con resistencia en campo a P. infestans mostró la presencia de cuatro   β (1,3 glucanasas después de infección con el patógeno. Las plantas se inocularon con el patógeno para inducir aumento en la concentración de las proteínas PR. Después de 15 días de inoculadas, se extrajo el líquido de lavado intercelular de los foliolos de la planta utilizando agua destilada. Las proteínas extraídas se liofilizaron, se  resuspendieron en buffer, se purificaron utilizando cromatografía de intercambio iónico y electroforesis preparativa,  esto permitió la  caracterización parcial de una β (1,3  glucanasa básica con peso molecular  de 36,8 kDa y PI  9,2 y tres ácidas de  35.4, 30.1 y 7.2 kDa  con puntos isoeléctricos de 3.8; 3.6 y 5.0 respectivamente. Además se determinaron las propiedades cinéticas de cada enzima, KM, Vmax, Eo y K3 encontrando que la proteína básica no ha sido reportada en la literatura hasta ahora.

  2. 致病疫霉拮抗芽孢杆菌的筛选及脂肽类物质分离的研究%Screening of Antagonistic Bacillus spp.Strains against Phytophthora infestans ( Mont.) de Bary and Isolation of Lipopeptide Substances

    Institute of Scientific and Technical Information of China (English)

    吴艳清; 蒋继志; 梁廷银

    2012-01-01

    [目的]筛选致病疫霉[Phytophthora infestans( Mont.) de Bary]拮抗芽孢杆菌并对其脂肽类物质进行分析.[方法]采用平板分离培养法从狗尾草[Setaria viridis(L)Beauv]根际土壤中分离产芽孢细菌,采用对峙培养法对其进行初筛和复筛,并对其中杀菌效果较好的Y-3菌株的脂肽类物质进行了HPLC分析.[结果]初筛有9株细菌对P.infestans具有一定的拮抗作用,复筛得到Y-1和Y-3菌株对P.infestans的生长具有明显的抑制作用,抑菌率选80%以上;Y-3菌株产生的脂肽粗提物对P.infestans具有较好的拮抗作用,抑制率达90%以上,HPLC分析显示其脂肽粗提物主要包括8种组分.[结论]Y-3菌株产生的脂肽类物质抑菌效果显著,在生物防治马铃薯晚疫病方面具有潜在的应用价值.%[ Objective] The paper was to screen the antagonistic Bacillus spp. strains against Phytophthora infestans (Mont. ) de Bary and analyze its lipopeptide substances. [ Method] Using flat isolation and culture method,the bacteria that could produce Bacillus were isolated from rhizosphere soil,and carried out primary and secondary screening by confrontation culture. The lipopeplide substances of Y-3 strain with better antifungal effect were carried out HPLC analysis. [ Result] Nine strains of bacteria had certain antagonistic effects against P. infesians in primary screening, Y-1 and Y-3 strains had significant inhibition effect against the growth of P. infestans in secondary screening,with inhibition rale higher than 80% ; the crude extract of lipopeplide produced by Y-3 strain had better antagonistic effect against P. infestans ,with inhibition rate higher than 90%. HPLC analysis showed that the crude extract of lipopeptide mainly contained 8 components. [ Conclusion ] The lipnpeptide substances produced by Y-3 strain had significant inhibition effect, which had potential application value for biological control of potato late blight.

  3. Mejoramiento Genético de la Papa en Colombia, para Resistencia a la "Gota" Causada por el PhytophthoraInfestans, (Mont. de Bary

    Directory of Open Access Journals (Sweden)

    Estrada Ramos Nelson

    1954-06-01

    Full Text Available Se hace una revisión de la literatura más importante y reciente publicada en EE. UU., Inglaterra, Holanda, Alemania y Rusia, países que más sehan preocupado por resolver el problema del Phytophthora en la papa, y la relacionada especialmente con el aspecto de pérdidas que causa, razas del parásito, métodos genéticos para la obtención de variedades resistentes y sistemas de prueba de la resistencia. Además se incluyen datos estadísticos para demostrar la importancia del Cultivo en el país. Se indican los métodos seguidos en Colombia para el mejoramiento, partiendo especialmente de líneas de la especie silvestre. S. demíssumcombinándola con las variedades nativas cultivadas del tipo andigenumadaptadas a grandes alturas y a los días cortos de los trópicos. Los resultados hasta la fecha indican la posibilidad de obtener después de 3 ó4 generaciones de retrocruzamientos, una buena variedad para cultivo y altamente resistente a la enfermedad. También se aconseja el empleo de líneas y variedades extranjeras resistentes, una vez que se hayan probado a las razas de Phytophthorapropias de Colombia. . Se indica que ya existe material de fitomejoramiento bastante avanzado que es prácticamente inmune pero que requiere subsiguiente mejoramiento. Hay probabilidades así, de obtener variedades inmunes o altamente resistentes a las razas actualmente existentes aunque su identidad parece no corresponder exactamente con las de otros países como Holanda, Inglaterra y Estados Unidos. Se establece una falta de identidad entre las pruebas de campo y las del laboratorio aunque pueden complementarse. Puede suponerse, de acuerdo con las reacciones obtenidas en el material extranjero resistente, la posibilidad de existencia de varias razas, pero no tan virulentas como en los países que tienen variedades resistentes. Es aconsejable el mejoramiento permanente de las variedades, para poder combatir los nuevos biotipos del pat

  4. Seleccion de híbridos de especies de papa por resistencia a Phytophthora infestans (Mont de Bary, fertilidad masculina y potencial productivo Hybrid selection of potatoe species for resistance to Phytophthora infestans (Mont de Bary, male fertility and productive potential

    Directory of Open Access Journals (Sweden)

    Ñustez L. Carlos Eduardo

    1990-12-01

    Full Text Available En la Universidad Nacional de Colombia en Mosquera durante los años 1988 y 1989 se realizó una investigación, donde se evaluó bajo condiciones de invernadero la resistencia a P. infestans de las progenies de 51 cruzamientos (F1 y avanzados. que inclu ían en su pedigree especies silvestres,
    primitivas y/o cultivadas de papa. Luego de un primer ciclo de selección los genotipos escogidos se evaluaron en campo por
    resistencia a la enfermedad, fertilidad masculina y potencial productivo (kg/planta. En invernadero se encontró buena resistencia a razas no específicas de P. infestans en las progenies de los cruzamientos simples con phureja, que incluían las especies silvestres polyadenium, stoloniferum, iopetslum, . avilesii y okadae y susceptibilidad en los que
    tenían las silvestres -dodsii, abancayense, embosinum, canasense, gandarillasii, pampasense, marinasense yalandiae. Al final del segundo ciclo de evaluación
    en campo se seleccionaron 27 genotipos: 5 de cruzamientos simples, 9 de cruzamientos triples y 2 de cruzamientos múltiples que incluyen especies silvestres en su pedigree
    (avilesii, brachycarpum, stotontterum, iopetalum, hougasii, eceule y los 11 restantes incluyen genotipos primitivos y/o avanzados. Un excelente potencial productivo se encontró
    en genotipos del cruzamiento interéspecífico avílesíi x phureja, y en genotipos de cruzamientos triples que incluyen las especies hougasii o acaule. La fertilidad masculina
    de los genotipo evaluados osciló desde esterilidad hasta alta fertilidad.An experiment was carriet out in one of the greenhouses of the Natíonal University of Colombia located in Bogotá, between 1988 and 1989. The objetive was to evaluate. the resistance to P. infestans of the progenies of 51 crosses (F1 and advanced that included in their pedigree wild, primitive specias and/or cultivated potatoes. Then after a first cycle of selection the chosen genotypes were evaluated in

  5. Microbe-independent entry of oomycete RxLR effectors and fungal RxLR-like effectors into plant and animal cells is specific and reproducible.

    Science.gov (United States)

    Tyler, Brett M; Kale, Shiv D; Wang, Qunqing; Tao, Kai; Clark, Helen R; Drews, Kelly; Antignani, Vincenzo; Rumore, Amanda; Hayes, Tristan; Plett, Jonathan M; Fudal, Isabelle; Gu, Biao; Chen, Qinghe; Affeldt, Katharyn J; Berthier, Erwin; Fischer, Gregory J; Dou, Daolong; Shan, Weixing; Keller, Nancy P; Martin, Francis; Rouxel, Thierry; Lawrence, Christopher B

    2013-06-01

    A wide diversity of pathogens and mutualists of plant and animal hosts, including oomycetes and fungi, produce effector proteins that enter the cytoplasm of host cells. A major question has been whether or not entry by these effectors can occur independently of the microbe or requires machinery provided by the microbe. Numerous publications have documented that oomycete RxLR effectors and fungal RxLR-like effectors can enter plant and animal cells independent of the microbe. A recent reexamination of whether the RxLR domain of oomycete RxLR effectors is sufficient for microbe-independent entry into host cells concluded that the RxLR domains of Phytophthora infestans Avr3a and of P. sojae Avr1b alone are NOT sufficient to enable microbe-independent entry of proteins into host and nonhost plant and animal cells. Here, we present new, more detailed data that unambiguously demonstrate that the RxLR domain of Avr1b does show efficient and specific entry into soybean root cells and also into wheat leaf cells, at levels well above background nonspecific entry. We also summarize host cell entry experiments with a wide diversity of oomycete and fungal effectors with RxLR or RxLR-like motifs that have been independently carried out by the seven different labs that coauthored this letter. Finally we discuss possible technical reasons why specific cell entry may have been not detected by Wawra et al. (2013).

  6. Dual RNA-sequencing of Eucalyptus nitens during Phytophthora cinnamomi challenge reveals pathogen and host factors influencing compatibility

    Directory of Open Access Journals (Sweden)

    Febe Elizabeth Meyer

    2016-03-01

    Full Text Available Damage caused by Phytophthora cinnamomi Rands remains an important concern on forest tree species. The pathogen causes root and collar rot, stem cankers and dieback of various economically important Eucalyptus spp. In South Africa, susceptible cold tolerant Eucalyptus plantations have been affected by various Phytophthora spp. with P. cinnamomi considered one of the most virulent. The molecular basis of this compatible interaction is poorly understood. In this study, susceptible Eucalyptus nitens plants were stem inoculated with P. cinnamomi and tissue was harvested five days post inoculation. Dual RNA-sequencing, a technique which allows the concurrent detection of both pathogen and host transcripts during infection, was performed. Approximately 1% of the reads mapped to the draft genome of P. cinnamomi while 78% of the reads mapped to the Eucalyptus grandis genome. The highest expressed P. cinnamomi gene in planta was a putative crinkler effector (CRN1. Phylogenetic analysis indicated the high similarity of this P. cinnamomi CRN1 to that of Phytophthora infestans. Some CRN effectors are known to target host nuclei to suppress defense. In the host, over 1400 genes were significantly differentially expressed in comparison to mock inoculated trees, including suites of pathogenesis related (PR genes. In particular, a PR-9 peroxidase gene with a high similarity to a Carica papaya PR-9 ortholog previously shown to be suppressed upon infection by Phytophthora palmivora was down-regulated two-fold. This PR-9 gene may represent a cross-species effector target during P. cinnamomi infection. This study identified pathogenicity factors, potential manipulation targets and attempted host defense mechanisms activated by E. nitens that contributed to the susceptible outcome of the interaction.

  7. 马铃薯POTHR-1 cDNA的克隆及晚疫病菌和其他非生物因子诱导表达分析%Cloning of Potato POTHR-1 Gene and Its Expression in Response to Infection by Phytophthora infestans and Other Abiotic Stimuli

    Institute of Scientific and Technical Information of China (English)

    田振东; 柳俊; 谢从华; 宋波涛

    2003-01-01

    利RACE和重叠延伸相结合的方法,从经晚疫病菌接种诱导的马铃薯水平抗性材料叶片中克隆了一个POTHE 1基因(potato Phytophthora infestans induced hypersensitive response related protein gene)的全长cDNA.序列分析表明,该基因编码225个氨基酸,与烟草harpin诱导蛋白基因hinl有很高的同源性(编码区核苷酸和氨基酸序列分别为83%和81%).Southern杂交结果显示在马铃薯基因组中有2~3个拷贝.对其诱导表达模式研究表明:晚疫病病原菌接种36 h后,该基因表达迅速增加;机械伤害及茉莉酸(JA)处理能够诱导表达;渗透胁迫(NaCl浸泡)能够诱导其微弱表达;但水杨酸(SA)不能诱导表达.该基因可能和病原与寄主互作时寄主产生过敏反应及细胞生理性死亡有关.%A complete cDNA of potato Phytophthora infestans-induced hypersensitive response-relatedprotein gene ( POTHR- 1) was cloned using rapid amplification of cDNA ends (RACE) strategy according to afragment sequence which we had cloned using suppression subtractive hybridization (SSH) technique. Thepotato POTHR-1gene encodes a protein of 225 amino acids, which shares 81% identity with tobacco bin1gene-enoded protein (harpin-induced protein). Southern blot revealed that there are two to three copies ofPOTHR- 1 in potato genome. The POTHR- 1 gene expression in potato leaves showed that its transcriptsaccumulated remarkably in leaves after 36 h inoculation with P. infestans. Mechanical wounding and jasmonicacid (JA) could induce the POTHR- 1 gene expression and osmotic stress just induce a slight accumulation ofPOTHR- 1 gene mRNA, while salicylic acid (SA) had no detectable function on the induction accumulation ofPOTHR- 1 gene transcripts. The potato POTHR- 1 gene may preferentially associate with hypersensitiveresponse (HR) or biotic cell death during interaction between host and pathogen.

  8. Phytophthora have distinct endogenous small RNA populations that include short interfering and microRNAs.

    Directory of Open Access Journals (Sweden)

    Noah Fahlgren

    Full Text Available In eukaryotes, RNA silencing pathways utilize 20-30-nucleotide small RNAs to regulate gene expression, specify and maintain chromatin structure, and repress viruses and mobile genetic elements. RNA silencing was likely present in the common ancestor of modern eukaryotes, but most research has focused on plant and animal RNA silencing systems. Phytophthora species belong to a phylogenetically distinct group of economically important plant pathogens that cause billions of dollars in yield losses annually as well as ecologically devastating outbreaks. We analyzed the small RNA-generating components of the genomes of P. infestans, P. sojae and P. ramorum using bioinformatics, genetic, phylogenetic and high-throughput sequencing-based methods. Each species produces two distinct populations of small RNAs that are predominantly 21- or 25-nucleotides long. The 25-nucleotide small RNAs were primarily derived from loci encoding transposable elements and we propose that these small RNAs define a pathway of short-interfering RNAs that silence repetitive genetic elements. The 21-nucleotide small RNAs were primarily derived from inverted repeats, including a novel microRNA family that is conserved among the three species, and several gene families, including Crinkler effectors and type III fibronectins. The Phytophthora microRNA is predicted to target a family of amino acid/auxin permeases, and we propose that 21-nucleotide small RNAs function at the post-transcriptional level. The functional significance of microRNA-guided regulation of amino acid/auxin permeases and the association of 21-nucleotide small RNAs with Crinkler effectors remains unclear, but this work provides a framework for testing the role of small RNAs in Phytophthora biology and pathogenesis in future work.

  9. Phytophthora have distinct endogenous small RNA populations that include short interfering and microRNAs.

    Science.gov (United States)

    Fahlgren, Noah; Bollmann, Stephanie R; Kasschau, Kristin D; Cuperus, Josh T; Press, Caroline M; Sullivan, Christopher M; Chapman, Elisabeth J; Hoyer, J Steen; Gilbert, Kerrigan B; Grünwald, Niklaus J; Carrington, James C

    2013-01-01

    In eukaryotes, RNA silencing pathways utilize 20-30-nucleotide small RNAs to regulate gene expression, specify and maintain chromatin structure, and repress viruses and mobile genetic elements. RNA silencing was likely present in the common ancestor of modern eukaryotes, but most research has focused on plant and animal RNA silencing systems. Phytophthora species belong to a phylogenetically distinct group of economically important plant pathogens that cause billions of dollars in yield losses annually as well as ecologically devastating outbreaks. We analyzed the small RNA-generating components of the genomes of P. infestans, P. sojae and P. ramorum using bioinformatics, genetic, phylogenetic and high-throughput sequencing-based methods. Each species produces two distinct populations of small RNAs that are predominantly 21- or 25-nucleotides long. The 25-nucleotide small RNAs were primarily derived from loci encoding transposable elements and we propose that these small RNAs define a pathway of short-interfering RNAs that silence repetitive genetic elements. The 21-nucleotide small RNAs were primarily derived from inverted repeats, including a novel microRNA family that is conserved among the three species, and several gene families, including Crinkler effectors and type III fibronectins. The Phytophthora microRNA is predicted to target a family of amino acid/auxin permeases, and we propose that 21-nucleotide small RNAs function at the post-transcriptional level. The functional significance of microRNA-guided regulation of amino acid/auxin permeases and the association of 21-nucleotide small RNAs with Crinkler effectors remains unclear, but this work provides a framework for testing the role of small RNAs in Phytophthora biology and pathogenesis in future work.

  10. Genome sequence of the necrotrophic plant pathogen Pythium ultimum reveals original pathogenicity mechanisms and effector repertoire.

    Science.gov (United States)

    The P. ultimum DAOM BR144 (=CBS 805.95 = ATCC200006) genome (42.8 Mb) encodes 15,290 genes, and has extensive sequence similarity and synteny with related Phytophthora spp., including the potato late blight pathogen Phytophthora infestans. Whole transcriptome sequencing revealed expression of 86 % o...

  11. Inhibiting Mechanism of the Extract of Introduced Trichoderma harzianum Strain T28 to Phytophthora infestans%哈茨木霉T28发酵液提取物对致病疫霉的抑制及对体内酶活性的影响

    Institute of Scientific and Technical Information of China (English)

    杨立宾; 宋瑞清; 李冲伟

    2013-01-01

    In order to further study the inhibiting activity and mechanism of ethyl acetate extracts of introduced Trichoderma harzianum strain T28 fermentation liquid to the growth of Phytophthora infestans, we investigated bacteriostasis of the extracts in different concentrations on P. infestans and their effects on several enzyme activities in the pest physiological metabolism. The results indicated that all the studied concentrations of the extracts had inhibiting effects on the growth, sporangium germination and spore released zoospores of P. infestans, and among the concentrations the 10 and 100 x diluted had slightly better effects without significant differences. The activities of protective enzymes ( SOD, CAT, POD and GSH - Px) of P. infestans treated with the extracts in 48 hours reduced by 89. 06% , 86. 96% , 97. 47% and 97. 63% , respectively. Meanwhile, the activities of carbohydrate metabolic enzymes ( HK、PK and LDH)and TCA aerobic catabolic enzymes (SDH and MDH)also decreased by 93% , 89.56% , 88.5% , 97.66% and 97.43% , energy - metabolic enzyme activities ( ATP) decreased by 98. 5% and 98. 67% . The MDA contents enhanced 60. 98% . This research determined that the ethyl acetate extract from fermentation liquid of T. harzianum strain T28 was able to reduce the metabolic enzyme activities of P. infestans and increase the MDA contents. The extracts could cause the damage to P. infestans and prevent from normal working of its glycometabolism, tricarboxylic acid cycle, energy metabolism and etc, which may be one of inhibiting mechanisms of ethyl acetate extracts of T. harzianum strain T28 on the growth of P. infestans.%为了更深入的探讨哈茨木霉菌株T28发酵液乙酸乙酯提取物对致病疫霉生长的抑制作用和机制,采用不同浓度的发酵液乙酸乙酯提取物对致病疫霉进行抑菌试验以及对其体内几种生理代谢酶活性影响进行试验.结果表明:不同浓度的提取物对致病疫霉菌丝生长、孢子囊

  12. Phytophthora lateralis.

    Science.gov (United States)

    E.M. Hansen

    2011-01-01

    Phytophthora lateralis was named by Tucker and Milbrath in 1942. There are no known synonyms. P. lateralis was classified in morphological group V by Stamps et al. (1990); the group includes homothallic species with paragynous antheridia and nonpapillate, proliferating sporangia.

  13. 哈茨木霉T28发酵液提取物对致病疫霉的抑菌作用及有效成分%Active Components of Extracts from the Fermentation Liquid of Trichoderma harzianum Strain T28 and Their Inhibiting Activities to Phytophthora infestans

    Institute of Scientific and Technical Information of China (English)

    杨立宾; 宋瑞清; 邓勋; 李冲伟

    2013-01-01

    Six extracts were obtained from the fermentation liquid of Trichoderma harzianum strain T28 by using different extract methods and organic solvents with different polarity.Inhibiting activities of the extracts on Phytophthora infestans were tested.The extracts with high inhibiting activities were further analyzed with GC-MS.The results indicated that the extracts obtained with step-by-step extraction method and ethyl acetate extract had the optimum inhibiting effect on mycelial growth,sporangium germination and sporangium released zoospores of P.infestans,with the inhibition rates of 67.06 percent,71.71 percent and 76.25 percent,respectively.Ethyl acetate-extracted ingredients in the sequential extraction and the direct extraction process were analyzed with GC-MS,and 10 and 15 components were identified,respectively; the same components in the two extraction methods included 2,5-di-tert-butylphenol,di-tert-butyl phthalate,diisobutyl phthalate,eighteen methyl carbonate,dibutyl phthalatel and mono-2-ethylhexyl Phthalate.These components might be the active chemical ingredients which inhibited P.infestans.%采用直接提取法和分步提取法对哈茨木霉T28发酵液进行萃取,获得6种提取物;将各提取物对致病疫霉进行抑菌活性研究,并对具有最佳抑菌效果的提取物进行GC-MS分析.结果表明:采用分步提取法和乙酸乙酯为萃取液的提取物对致病疫霉菌丝生长、孢子囊萌发、孢子囊释放游动孢子具有最佳的抑制效果,抑制率分别为67.06%,71.71%和76.25%;采用直接提取法获得的提取物抑制效果次之.2种方法的提取物中分别含有10个和15个组分,其中相同组分为2,5-二叔丁基酚、邻苯二甲酸二叔丁酯、邻苯二甲酸二异丁酯、十八碳酸甲酯、邻苯二甲酸二丁酯和邻苯二甲酸单(2-二乙基己基)酯,这些组分可能为对致病疫霉菌具有抑制作用的有效成分.

  14. Efectos de Purines de Chipaca (Bidens pilosa L. y de Microorganismos en la Incidencia y Severidad de Phytophthora infestans (Mont. De Bary en Papa Criolla (Solanum phureja Cultivada en Tenjo (Cundinamarca, Colombia / Effects of Chipaca (Bidens pilosa

    Directory of Open Access Journals (Sweden)

    Tomas Enrique León Sicard

    2013-12-01

    Full Text Available En una finca ecológica del municipio de Tenjo(Cundinamarca-Colombia se estudió el efecto de variosmateriales preparados a partir de chipaca (Bidens pilosa y deaislamientos microbianos, sobre la incidencia y severidad deP. infestans en un cultivo de papa criolla (Solanum phureja,utilizando un diseño completamente al azar (DCA consubmuestreo y ocho tratamientos: purín de flores; purín mezcla; actinomiceto AC 12 (Streptomyces sp.; mezcla de actinomicetos; aislamiento bacteriano (Bacillus subtilis; mezcla bacterias (Bacillus subtilis y Burkholderia cepacia; Hongo (Geotrichum sp. y un control (agua destilada estéril. Los resultados mostraron rápida incidencia de la enfermedad, que fue evidente a los 36 días después de la siembra (dds y alcanzó 100% de afectacióna los 52 dds sin diferencias entre tratamientos. La severidadfue estadísticamente diferente únicamente en el tratamientode “purín de flores”, que se diferenció significativamente deltratamiento control entre los 56 y 70 dds (27,8% menos lo que fortalece resultados de ensayos anteriores sobre su potencial como posible producto biocontrolador de la Gota. Resultados menores de severidad frente al control (no significativos también se obtuvieron con los tratamientos “purín mezcla” y “mezcla de actinomicetos”, entre los 60 y 87 dds / In an organic farm of Tenjo (Cundinamarca, Colombiathe effect of various materials prepared from chipaca (Bidenspilosa and microbial isolates, on the incidence and severity ofP. infestans in potato (Solanum phureja were studied usinga completely randomized design (CRD with subsampling andeight treatments: flowers slurry, mixed slurry; actinomyceteAC 12 (Streptomyces sp., mix actinomycetes; isolationbacterial (Bacillus subtilis ; mixed bacteria (Bacillus subtilisand Burkholderia cepacia; fungus (Geotrichum sp. and acontrol (sterile distilled water. The results showed rapid disease incidence, which was evident at 36 days after planting (dap

  15. Phytophthora Species, New Threats to the Plant Health in Korea

    OpenAIRE

    Ik-Hwa Hyun; Woobong Choi

    2014-01-01

    Given the lack of a resistant genetic pool in host plants, the introduction of exotic invasive pathogens can result in epidemics that affect a specific ecosystem and economy. Plant quarantine, which is designed to protect endemic plant resources, is a highly invaluable safeguard that should keep biosecurity with increasing international trade and global transportation. A total of 34 species of plant pathogens including Phytophthora infestans were documented as introduced from other countries ...

  16. Mitochondrial genome sequences reveal evolutionary relationships of the Phytophthora 1c clade species.

    Science.gov (United States)

    Lassiter, Erica S; Russ, Carsten; Nusbaum, Chad; Zeng, Qiandong; Saville, Amanda C; Olarte, Rodrigo A; Carbone, Ignazio; Hu, Chia-Hui; Seguin-Orlando, Andaine; Samaniego, Jose A; Thorne, Jeffrey L; Ristaino, Jean B

    2015-11-01

    Phytophthora infestans is one of the most destructive plant pathogens of potato and tomato globally. The pathogen is closely related to four other Phytophthora species in the 1c clade including P. phaseoli, P. ipomoeae, P. mirabilis and P. andina that are important pathogens of other wild and domesticated hosts. P. andina is an interspecific hybrid between P. infestans and an unknown Phytophthora species. We have sequenced mitochondrial genomes of the sister species of P. infestans and examined the evolutionary relationships within the clade. Phylogenetic analysis indicates that the P. phaseoli mitochondrial lineage is basal within the clade. P. mirabilis and P. ipomoeae are sister lineages and share a common ancestor with the Ic mitochondrial lineage of P. andina. These lineages in turn are sister to the P. infestans and P. andina Ia mitochondrial lineages. The P. andina Ic lineage diverged much earlier than the P. andina Ia mitochondrial lineage and P. infestans. The presence of two mitochondrial lineages in P. andina supports the hybrid nature of this species. The ancestral state of the P. andina Ic lineage in the tree and its occurrence only in the Andean regions of Ecuador, Colombia and Peru suggests that the origin of this species hybrid in nature may occur there.

  17. 青海海东地区马铃薯晚疫病菌生理小种的组成及分布%Composition and distribution of physiological race of Phytophthora infestans in the Haidong region of Qinghai province

    Institute of Scientific and Technical Information of China (English)

    叶广继; 孙海宏; 周云; 杨永智; 王舰

    2008-01-01

    致病疫霉(Phytophthora infestans)引起的马铃薯晚疫病是马铃薯的毁灭性病害,全世界普遍发生,危害严重,已列为世界粮食作物第一大病害。晚疫病菌具有明显的生理分化现象,根据它的寄主专化型可以分为许多生理小种,并具有对不同品种的侵袭致病力。随着马铃薯生产的快速发展,品种调运的频繁,促进了马铃薯晚疫病菌的变异和生理小种的复杂化,对当地原有的专化抗病品种的致病性日益增强,

  18. Structural Basis of Host Autophagy-related Protein 8 (ATG8) Binding by the Irish Potato Famine Pathogen Effector Protein PexRD54.

    Science.gov (United States)

    Maqbool, Abbas; Hughes, Richard K; Dagdas, Yasin F; Tregidgo, Nicholas; Zess, Erin; Belhaj, Khaoula; Round, Adam; Bozkurt, Tolga O; Kamoun, Sophien; Banfield, Mark J

    2016-09-16

    Filamentous plant pathogens deliver effector proteins to host cells to promote infection. The Phytophthora infestans RXLR-type effector PexRD54 binds potato ATG8 via its ATG8 family-interacting motif (AIM) and perturbs host-selective autophagy. However, the structural basis of this interaction remains unknown. Here, we define the crystal structure of PexRD54, which includes a modular architecture, including five tandem repeat domains, with the AIM sequence presented at the disordered C terminus. To determine the interface between PexRD54 and ATG8, we solved the crystal structure of potato ATG8CL in complex with a peptide comprising the effector's AIM sequence, and we established a model of the full-length PexRD54-ATG8CL complex using small angle x-ray scattering. Structure-informed deletion of the PexRD54 tandem domains reveals retention of ATG8CL binding in vitro and in planta This study offers new insights into structure/function relationships of oomycete RXLR effectors and how these proteins engage with host cell targets to promote disease.

  19. 五种杀菌剂对马铃薯晚疫病菌孢子萌发的抑制作用%Inhibition Effect of Five Fungicides on Spore Germination of Phytophthora infestans

    Institute of Scientific and Technical Information of China (English)

    朱丽丹; 徐进; 杨志辉; 朱杰华; 赵冬梅

    2015-01-01

    测定河北双吉75%代森锰锌水分散粒剂、河北双吉80%代森锰锌可湿性粉剂、美国陶氏80%代森锰锌可湿性粉剂、25%双炔酰菌胺悬浮剂和68.75%氟菌,霜霉威悬浮剂5种杀菌剂对马铃薯晚疫病菌[Phytophthora infestans (Mont.) de Bary]孢子囊直接萌发、间接萌发(释放游动孢子)及游动孢子萌发的抑制作用.结果表明,5种杀菌剂对孢子囊直接萌发的抑制效果均比较好,而对孢子囊间接萌发和游动孢子萌发的抑制效果各不相同.其中,河北双吉75%代森锰锌水分散粒剂和河北双吉80%代森锰锌可湿性粉剂对孢子囊直接和间接萌发的抑制效果最显著,浓度在5 μg/mL以上时抑制率均为100%.美国陶氏80%代森锰锌可湿性粉剂和25%双炔酰菌胺悬浮剂,浓度在20μg/mL时几乎能完全抑制孢子囊的直接萌发或间接萌发,68.75%氟菌·霜霉威悬浮剂对孢子囊间接萌发的抑制作用相对较差.游动孢子的萌发对5种药剂较为敏感,1 μg/mL的药剂浓度就能使游动孢子萌发得到显著抑制.

  20. Evaluación preliminar del efecto que sobre algunas enzimas del suelo tienen diferentes mecanismos de control del hongo (Phytophthora infestans en un cultivo de papa (Solanum tuberosum bajo dos tipos de manejo agrícola (orgánico y convencional

    Directory of Open Access Journals (Sweden)

    Guardiola Marta Lucía

    2004-12-01

    Full Text Available Se evaluó comparativamente el posible efecto diferencial que, sobre la actividad de las enzimas proteasa, fosfatasa ácida, fosfatasa alcalina y celulasa, además del pH y la materia orgánica del suelo, tuvieron los métodos de control de Phytophthora infestans tanto en la agricultura orgánica (purín de Chipaca Bidens pilosum como en la convencional (diversos fungicidas comerciales en plantas de papa (Solanum tuberosum. Igualmente, en los parámetros antes mencionados, se evaluó el efecto de un promotor fúngico utilizado como control del mismo hongo en ambas agriculturas. La investigación se dividió en una fase de campo y una de laboratorio. En la fase de campo, realizada durante siete meses de 1999, se acompañó la siembra, el desarrollo del cultivo y evolución de la enfermedad a través de la determinación de la incidencia y su severidad. En el laboratorio se determinó la actividad enzimática proteasa, fosfatasa ácida, fosfatasa alcalina, celulasa, así como también el pH y porcentaje de materia orgánica. Se encontró que en el manejo agrícola orgánico la actividad de la fosfatasa ácida, la fosfatasa alcalina y la proteasa así como también el pH fueron más influenciados por el estado de desarrollo de las plantas que por efecto del los tratamientos utilizados en el control del hongo. En el manejo agrícola convencional la actividad enzimática de las celulasas fue inhibida significativamente por los fungicidas. La actividad de las proteasas y fosfatasas ácidas fueron estimuladas por efecto de los fungicidas comerciales y por el estado de desarrollo de las plantas. Las actividades enzimáticas fosfatasa ácida, proteasa y celulasa presentaron comportamientos significativamente diferentes entre los cultivos convencional y orgánico. Para el control de la enfermedad, el uso de los fungicidas fue el tratamiento que mejores resultados presentó con una mayor producción de papa pero con mayores gastos de producción, mientras

  1. Phytophthora species, new threats to the plant health in Korea.

    Science.gov (United States)

    Hyun, Ik-Hwa; Choi, Woobong

    2014-12-01

    Given the lack of a resistant genetic pool in host plants, the introduction of exotic invasive pathogens can result in epidemics that affect a specific ecosystem and economy. Plant quarantine, which is designed to protect endemic plant resources, is a highly invaluable safeguard that should keep biosecurity with increasing international trade and global transportation. A total of 34 species of plant pathogens including Phytophthora infestans were documented as introduced from other countries into Korea from 1900 to 2010. The genus Phytophthora, classified in oomycetes, includes more than 120 species that are mostly recognized worldwide as highly invasive plant pathogens. After 2000, over 50 new species of Phytophthora were identified internationally as plant pathogens occurring in crops and forest trees. In Korea, Phytophthora is also one of the most serious plant pathogens. To date, 22 species (about one-fifth of known species) of the genus have been identified and reported as plant pathogens in the country. The likelihood of new exotic Phytophthora species being introduced into Korea continues to increase, thus necessitating intensive plant quarantine inspections. As new potential threats to plant health in Korea, six Phytophthora species, namely, P. alni, P. inundata, P. kernoviae, P. pinifolia, P. quercina, and P. ramorum, are discussed in this review with focus on history, disease, biology, management, and plant quarantine issues.

  2. Change of predominant genotypes of Phytophthora infestans in Tokachi district, Hokkaido, Japan and difference of lesion productivity to the field resistant cultivar 'Matilda' among genotypes%在日本北海道Tokachi district, 马铃薯晚疫病菌占主导地位的基因型的变化及不同基因型在水平抗病品种‘Matilda'上产生不同病斑的研究

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    在Memuro城镇,位于日本北海道Tokachi地区中部,主要种植田间抗病品种Matilda.1998年马铃薯晚疫病在此品种上发生较前几年早.为了了解Matilda品种抗性降低的原因,对1996-1999年Tokachi地区的晚疫病菌基因型的时间变化进行了研究及不同基因型间病菌产生病斑能力进行了比较.在1997年以前基因型JP-1在Tokachi地区占主导地位.在1997年基因型A首次在Tokachi地区被发现并且局限在Tokachi北部.在1998和1999年基因型A遍及整个Tokachi地区,1999年其比例上升至72%.用孢子囊悬浮液接种法检测不同基因型病菌对Matilda品种的致病力结果发现,基因型A比基因型JP-1和基因型B产生更大的病斑.然而通过液滴接种法所有3个基因型都可产生扩展的病斑.结果表明,Matilda减少的田间抗性是由于基因型A 传播到Memuro城镇的Matilda品种上所致.%The field resistant cultivar ‘Matilda' has been grown chiefly in Memuro town, at the central part of Tokachi district, Hokkaido, Japan. The cultivar blighted by Phytophthora infestans was unusually earlier in 1998 than that in the previous years. To know the reason why ‘Matilda' became weak, temporal change of genotypes of P. infestans was studied in Tokachi district from 1996 to 1999, and the ability to produce lesions were compared among genotypes. Before 1997, the genotype JP-1 of Phytophthora infestans was highly predominant in Tokachi district. The genotype A for the first time occurred in Tokachi in 1997, and was confined to northern Tokachi. It became common throughout Tokachi in 1998 and 1999, and its proportion increased up to 72% in 1999. The genotype A produced the higher number of lesions on ‘Matilda' than the genotype JP-1 and the genotype B by spray inoculation of sporangial suspension, while all the three genotypes produced progressing lesions by drop inoculation. The results suggested that the reduced field resistance of ‘Matilda' was due to that

  3. 不同浓度臭氧水对致病疫霉菌Phytophthora infestans孢子萌发抑制作用初报%Inhibitory Effects of Ozone Solution at Different Concentrations on Spore Germination of Phytophthora infestans (Mont.) de Bary

    Institute of Scientific and Technical Information of China (English)

    徐常青; 魏建健; 曹克强

    2009-01-01

    采用不同浓度臭氧水对致病疫霉菌Phytophthora infestarts(Mont.)de Bary孢子囊萌发进行了试验,结果表明:臭氧水处理对孢子囊萌发的影响与臭氧水浓度密切相关,以9 mg/kg臭氧水处理1 min可以抑制95%以上孢子囊萌发,以18 mg/kg臭氧水处理1 min则100%抑制孢子囊萌发.无论在高浓度还是在低浓度条件下,处理时间1 min或2min对孢子囊萌发没有产生显著影响,杀菌作用几乎是瞬间完成的.臭氧水处理孢子囊后导致孢子囊形态发生变化,这种变化随时间延长变得更加明显.鉴于高浓度臭氧水对植物本身不产生毒害作用,因此,高浓度臭氧水在控制晚疫病方面显示出广阔的应用前景.

  4. Fourier-Transformed Infrared Spectroscopy Applied for Studying Compatible Interaction in the Pathosystem Phytophtora infestans-Solanum tuberosum

    OpenAIRE

    Abdelmoumen TAOUTAOU; Socaciu, Carmen; Doru PAMFIL; Florinela FETEA; Erika BALAZS; Constantin BOTEZ; Adina CHIS; Daniela BRICIU; Alexandru BRICIU

    2010-01-01

    In this study we used the Fourier-Transformed Infrared (FT-IR) technique to examine the compatible reaction of potato (Solanum tuberosum) to infection by the late blight agent Phytophthora infestans. Three virulent isolates have been used, different by their level of pathogenicity on R2 potato. The response was dependent on the pathogenicity of the isolate. The Infrared spectra in the middle infrared region (MIR) of infested versus healthy (control) leaves showed that controls absorb (intensi...

  5. Five reasons to consider Phytophthora infestans a reemerging pathogen

    Science.gov (United States)

    The Late blight disease of potato and tomato (and several other Solanaceous plants) has emerged and re-emerged so many times, that it might be logical to conclude that nothing new could be said about this disease. And yet, much continues to be said (and written). In the year 2007, a search for Phyto...

  6. Comparative structural and functional analysis of genes encoding pectin methylesterases in Phytophthora spp.

    Science.gov (United States)

    Mingora, Christina; Ewer, Jason; Ospina-Giraldo, Manuel

    2014-03-15

    We have scanned the Phytophthora infestans, P. ramorum, and P. sojae genomes for the presence of putative pectin methylesterase genes and conducted a sequence analysis of all gene models found. We also searched for potential regulatory motifs in the promoter region of the proposed P. infestans models, and investigated the gene expression levels throughout the course of P. infestans infection on potato plants, using in planta and detached leaf assays. We found that genes located on contiguous chromosomal regions contain similar motifs in the promoter region, indicating the possibility of a shared regulatory mechanism. Results of our investigations also suggest that, during the pathogenicity process, the expression levels of some of the analyzed genes vary considerably when compared to basal expression observed in in vitro cultures of non-sporulating mycelium. These results were observed both in planta and in detached leaf assays.

  7. Phytophthora borealis and Phytophthora riparia, new species in Phytophthora ITS Clade 6.

    Science.gov (United States)

    Hansen, Everett M; Reeser, Paul W; Sutton, Wendy

    2012-01-01

    Phytophthora borealis and Phytophthora riparia, identified in recent Phytophthora surveys of forest streams in Oregon, California and Alaska, are described as new species in Phytophthora ITS Clade 6. They are similar in growth form and morphology to P. gonapodyides and are predominantly sterile. They present unique DNA sequences, however, and differ in temperature/growth relations and geographic distribution.

  8. Use of genome sequence data in the design and testing of SSR markers for Phytophthora species

    Directory of Open Access Journals (Sweden)

    Cardle Linda

    2008-12-01

    Full Text Available Abstract Background Microsatellites or single sequence repeats (SSRs are a powerful choice of marker in the study of Phytophthora population biology, epidemiology, ecology, genetics and evolution. A strategy was tested in which the publicly available unigene datasets extracted from genome sequences of P. infestans, P. sojae and P. ramorum were mined for candidate SSR markers that could be applied to a wide range of Phytophthora species. Results A first approach, aimed at the identification of polymorphic SSR loci common to many Phytophthora species, yielded 171 reliable sequences containing 211 SSRs. Microsatellites were identified from 16 target species representing the breadth of diversity across the genus. Repeat number ranged from 3 to 16 with most having seven repeats or less and four being the most commonly found. Trinucleotide repeats such as (AAGn, (AGGn and (AGCn were the most common followed by pentanucleotide, tetranucleotide and dinucleotide repeats. A second approach was aimed at the identification of useful loci common to a restricted number of species more closely related to P. sojae (P. alni, P. cambivora, P. europaea and P. fragariae. This analysis yielded 10 trinucleotide and 2 tetranucleotide SSRs which were repeated 4, 5 or 6 times. Conclusion Key studies on inter- and intra-specific variation of selected microsatellites remain. Despite the screening of conserved gene coding regions, the sequence diversity between species was high and the identification of useful SSR loci applicable to anything other than the most closely related pairs of Phytophthora species was challenging. That said, many novel SSR loci for species other than the three 'source species' (P. infestans, P. sojae and P. ramorum are reported, offering great potential for the investigation of Phytophthora populations. In addition to the presence of microsatellites, many of the amplified regions may represent useful molecular marker regions for other studies as

  9. Proteínas antifúngicas contra p. infestans en los espacios intercelulares de hojas de tomate (lycopersicon esculentum cerasiforme) posibles defensinas de plantas

    OpenAIRE

    Luz Dary Riaño; Humberto Miguel Zamora

    2008-01-01

    Se aislaron y caracterizaron parcialmente proteínas antifúngicas de los espacios intercelulares de hojas de tomate Lycopersicon esculentum cerasiforme, variedad que ha mostrado resistencia en campo a Phytophthora Infestans; se observó quedespués de inoculación con el patógeno dichas proteínas se acumularon sistémicamente en la planta. Las proteínas identificadasmostraron características de Defensinas de plantas, una nueva f...

  10. The CAZyome of Phytophthora spp.: A comprehensive analysis of the gene complement coding for carbohydrate-active enzymes in species of the genus Phytophthora

    Directory of Open Access Journals (Sweden)

    Laird Emma W

    2010-09-01

    Full Text Available Abstract Background Enzymes involved in carbohydrate metabolism include Carbohydrate esterases (CE, Glycoside hydrolases (GH, Glycosyl transferases (GT, and Polysaccharide lyases (PL, commonly referred to as carbohydrate-active enzymes (CAZymes. The CE, GH, and PL superfamilies are also known as cell wall degrading enzymes (CWDE due to their role in the disintegration of the plant cell wall by bacterial and fungal pathogens. In Phytophthora infestans, penetration of the plant cells occurs through a specialized hyphal structure called appressorium; however, it is likely that members of the genus Phytophthora also use CWDE for invasive growth because hyphal forces are below the level of tensile strength exhibited by the plant cell wall. Because information regarding the frequency and distribution of CAZyme coding genes in Phytophthora is currently unknown, we have scanned the genomes of P. infestans, P. sojae, and P. ramorum for the presence of CAZyme-coding genes using a homology-based approach and compared the gene collinearity in the three genomes. In addition, we have tested the expression of several genes coding for CE in cultures grown in vitro. Results We have found that P. infestans, P. sojae and P. ramorum contain a total of 435, 379, and 310 CAZy homologs; in each genome, most homologs belong to the GH superfamily. Most GH and PL homologs code for enzymes that hydrolyze substances present in the pectin layer forming the middle lamella of the plant cells. In addition, a significant number of CE homologs catalyzing the deacetylation of compounds characteristic of the plant cell cuticle were found. In general, a high degree of gene location conservation was observed, as indicated by the presence of sequential orthologous pairs in the three genomes. Such collinearity was frequently observed among members of the GH superfamily. On the other hand, the CE and PL superfamilies showed less collinearity for some of their putative members

  11. The hidden duplication past of the plant pathogen Phytophthora and its consequences for infection

    Directory of Open Access Journals (Sweden)

    Martens Cindy

    2010-06-01

    Full Text Available Abstract Background Oomycetes of the genus Phytophthora are pathogens that infect a wide range of plant species. For dicot hosts such as tomato, potato and soybean, Phytophthora is even the most important pathogen. Previous analyses of Phytophthora genomes uncovered many genes, large gene families and large genome sizes that can partially be explained by significant repeat expansion patterns. Results Analysis of the complete genomes of three different Phytophthora species, using a newly developed approach, unveiled a large number of small duplicated blocks, mainly consisting of two or three consecutive genes. Further analysis of these duplicated genes and comparison with the known gene and genome duplication history of ten other eukaryotes including parasites, algae, plants, fungi, vertebrates and invertebrates, suggests that the ancestor of P. infestans, P. sojae and P. ramorum most likely underwent a whole genome duplication (WGD. Genes that have survived in duplicate are mainly genes that are known to be preferentially retained following WGDs, but also genes important for pathogenicity and infection of the different hosts seem to have been retained in excess. As a result, the WGD might have contributed to the evolutionary and pathogenic success of Phytophthora. Conclusions The fact that we find many small blocks of duplicated genes indicates that the genomes of Phytophthora species have been heavily rearranged following the WGD. Most likely, the high repeat content in these genomes have played an important role in this rearrangement process. As a consequence, the paucity of retained larger duplicated blocks has greatly complicated previous attempts to detect remnants of a large-scale duplication event in Phytophthora. However, as we show here, our newly developed strategy to identify very small duplicated blocks might be a useful approach to uncover ancient polyploidy events, in particular for heavily rearranged genomes.

  12. Phytophthora beyond agriculture.

    Science.gov (United States)

    Hansen, Everett M; Reeser, Paul W; Sutton, Wendy

    2012-01-01

    Little is known about indigenous Phytophthora species in natural ecosystems. Increasing evidence, however, suggests that a diverse, trophically complex Phytophthora community is important in many forests. The number of described species has steadily increased, with a dramatic spike in recent years as new species have been split from old and new species have been discovered through exploration of new habitats. Forest soil, streams, and the upper canopies of trees are now being explored for Phytophthora diversity, and a new appreciation for the ecological amplitude of the genus is emerging. Ten to twenty species are regularly identified in temperate forest surveys. Half or more of this Phytophthora diversity comes from species described since 2000. Taxa in internal transcribed spacer (ITS) Clade 6 are especially numerous in forest streams and may be saprophytic in this habitat. Three ecological assemblages of forest Phytophthora species are hypothesized: aquatic opportunists, foliar pathogens, and soilborne fine-root and canker pathogens. Aggressive invasive species are associated with all three groups.

  13. Fighting phytophthora in blueberries

    Science.gov (United States)

    Phytophthora cinnamomi Rands is a ubiquitous soilborne pathogen associated with root rot in many woody perennial plant species, including highbush blueberry (Vaccinium sp.). To identify genotypes with resistance to the pathogen, cultivars and advanced selections of highbush blueberry were grown in a...

  14. Molecular evolution of an Avirulence Homolog (Avh) gene subfamily in Phytophthora ramorum

    Science.gov (United States)

    GossErica M.; Caroline M. Press; Niklaus J. Grünwald

    2008-01-01

    Pathogen effectors can serve a virulence function on behalf of the pathogen or trigger a rapid defense response in resistant hosts. Sequencing of the Phytophthora ramorum genome and subsequent analysis identified a diverse superfamily of approximately 350 genes that are homologous to the four known avirulence genes in plant pathogenic oomycetes and...

  15. Vroegtijdig Phytophthora opsporen met biosensor

    NARCIS (Netherlands)

    Jansen, R.M.C.

    2003-01-01

    Phytophthora kan vroegtijdig worden opgespoord met biosensoren. Bij de Leerstoelgroep Agrarische Bedrijfstechnologie van Wageningen Universiteit wordt verder gekeken naar praktische toepassingen van deze techniek

  16. Draft genome sequences of Phytophthora kernoviae and Phytophthora ramorum lineage EU2 from Scotland

    OpenAIRE

    Christine Sambles; Alexandra Schlenzig; Paul O'Neill; Murray Grant; Studholme, David J.

    2015-01-01

    Newly discovered Phytophthora species include invasive pathogens that threaten trees and shrubs. We present draft genome assemblies for three isolates of Phytophthora kernoviae and one isolate of the EU2 lineage of Phytophthora ramorum, collected from outbreak sites in Scotland.

  17. Sequencing of the Litchi Downy Blight Pathogen Reveals It Is a Phytophthora Species With Downy Mildew-Like Characteristics.

    Science.gov (United States)

    Ye, Wenwu; Wang, Yang; Shen, Danyu; Li, Delong; Pu, Tianhuizi; Jiang, Zide; Zhang, Zhengguang; Zheng, Xiaobo; Tyler, Brett M; Wang, Yuanchao

    2016-07-01

    On the basis of its downy mildew-like morphology, the litchi downy blight pathogen was previously named Peronophythora litchii. Recently, however, it was proposed to transfer this pathogen to Phytophthora clade 4. To better characterize this unusual oomycete species and important fruit pathogen, we obtained the genome sequence of Phytophthora litchii and compared it to those from other oomycete species. P. litchii has a small genome with tightly spaced genes. On the basis of a multilocus phylogenetic analysis, the placement of P. litchii in the genus Phytophthora is strongly supported. Effector proteins predicted included 245 RxLR, 30 necrosis-and-ethylene-inducing protein-like, and 14 crinkler proteins. The typical motifs, phylogenies, and activities of these effectors were typical for a Phytophthora species. However, like the genome features of the analyzed downy mildews, P. litchii exhibited a streamlined genome with a relatively small number of genes in both core and species-specific protein families. The low GC content and slight codon preferences of P. litchii sequences were similar to those of the analyzed downy mildews and a subset of Phytophthora species. Taken together, these observations suggest that P. litchii is a Phytophthora pathogen that is in the process of acquiring downy mildew-like genomic and morphological features. Thus P. litchii may provide a novel model for investigating morphological development and genomic adaptation in oomycete pathogens.

  18. Lipidperoxidative and proteolytic processes in fungi under the influence of xenobiotica. [Botrytis cinerea; Phytophora infestans

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, H.M.; Edlich, W.; Lyr, H.

    1986-01-01

    As a model system for the investigation of peroxidative effects in the phytopathogenic fungi Botrytis cinerea in submers culture was used. The influence was investigated of hydrogenperoxide with biochemical and cytological methods. The hyphae showed significant changes of the ultrastructure: swelling and vacuolization of mitochondria, loss of ribosomes, vesiculation of endoplasmic reticulum, degradation and lysis of the cell ribosomes, and deposition of lipid droplets on the membranes and in the cytoplasm, dependent on the concentration of the peroxide. Same effects with higher injuries of the membrane system are found in Phytophthorea infestans. A parallel investigation on fibroblasts showed similar effects: pathological changes of mitochondria, but also pycnosis in the nucleus. Comparative ultrastructure investigations were performed in cultures of Phytophthora infestans with tetrachlorcarbon and chloroneb, a specific fungicide substance with a new mode of action. Scavengers like ..cap alpha..-tocopherol and piperonyl butoxide inhibit the toxic effect of the investigated substances in various degrees. Results are discussed in regard to the effect of a lipid peroxidative and proteolytic attack in pesticides of unknown mechanism of action.

  19. The anti-Phytophthora effect of selected potato-associated Pseudomonas strains: from the laboratory to the field

    Directory of Open Access Journals (Sweden)

    Anouk eGuyer

    2015-11-01

    Full Text Available Late blight, caused by the oomycete Phytophthora infestans, is the most devastating disease of potato. In organic farming, late Late blight, caused by the oomycete Phytophthora infestans, is the most devastating disease of potato. In organic farming, late blight is controlled by repeated applications of copper-based products, which negatively impact the environment. To find alternative solutions for late blight management, we have previously isolated a large collection of bacteria from the phyllosphere and the rhizosphere of potatoes. Here we report the antagonistic potential of these strains when co-cultivated with P. infestans as well as with other potato pathogens. We then focused on three Pseudomonas strains and compared their protective impact against late blight to that of well-known biocontrol strains in planta using a high-throughput leaf disc assay with automated picture analysis. When sprayed on the leaves of potatoes in the greenhouse, the strains were able to survive for at least 15 days. Under field conditions, populations decreased faster but all tested strains could still be retrieved after 8 days. The most active strain in vitro, P. chlororaphis R47, was also the best protectant on leaf discs from plants grown in the greenhouse experiment, but its protection potential could not be verified in the field due to unfavourable infection conditions. However, its protective effect against P. infestans in planta, its survival in the phyllosphere as well as its ability to colonise the potato rhizosphere in very high population densities, suggest a potential for field application, e.g. in the form of tuber treatment or leaf spray.

  20. PsVPS1, a Dynamin-Related Protein, Is Involved in Cyst Germination and Soybean Infection of Phytophthora sojae

    OpenAIRE

    Delong Li; Zhijian Zhao; Yidan Huang; Zhaojun Lu; Meng Yao; Yujuan Hao; Chunhua Zhai; Yuanchao Wang

    2013-01-01

    Plant pathogens secrete effector proteins to suppress plant immunity. However, the mechanism by which oomycete pathogens deliver effector proteins during plant infection remains unknown. In this report, we characterized a Phytophthora sojae vps1 gene. This gene encodes a homolog of the Saccharomyces cerevisiae vacuolar protein sorting gene vps1 that mediates budding of clathrin-coated vesicles from the late Golgi, which are diverted from the general secretory pathway to the vacuole. PsVPS1-si...

  1. Interaction between the moss Physcomitrella patens and Phytophthora: a novel pathosystem for live-cell imaging of subcellular defence.

    Science.gov (United States)

    Overdijk, Elysa J R; DE Keijzer, Jeroen; DE Groot, Deborah; Schoina, Charikleia; Bouwmeester, Klaas; Ketelaar, Tijs; Govers, Francine

    2016-08-01

    Live-cell imaging of plant-pathogen interactions is often hampered by the tissue complexity and multicell layered nature of the host. Here, we established a novel pathosystem with the moss Physcomitrella patens as host for Phytophthora. The tip-growing protonema cells of this moss are ideal for visualizing interactions with the pathogen over time using high-resolution microscopy. We tested four Phytophthora species for their ability to infect P. patens and showed that P. sojae and P. palmivora were only rarely capable to infect P. patens. In contrast, P. infestans and P. capsici frequently and successfully penetrated moss protonemal cells, showed intracellular hyphal growth and formed sporangia. Next to these successful invasions, many penetration attempts failed. Here the pathogen was blocked by a barrier of cell wall material deposited in papilla-like structures, a defence response that is common in higher plants. Another common response is the upregulation of defence-related genes upon infection and also in moss we observed this upregulation in tissues infected with Phytophthora. For more advanced analyses of the novel pathosystem we developed a special set-up that allowed live-cell imaging of subcellular defence processes by high-resolution microscopy. With this set-up, we revealed that Phytophthora infection of moss induces repositioning of the nucleus, accumulation of cytoplasm and rearrangement of the actin cytoskeleton, but not of microtubules.

  2. The Study on Isolating and Culturing Phytophthora infestans%致病疫霉(Phytophthora infestans)的分离与培养方法

    Institute of Scientific and Technical Information of China (English)

    毕朝位; 黎艳平; 罗国全

    2005-01-01

    针对不同地区的病样,分别采用直接分离法、保湿培养分离法、薯片夹叶分离法、薯片诱导分离法等分离方法,利用选择性培养基SRA进行分离,通过挑取菌落边缘菌丝尖端于斜面培养基进行纯化,共获得重庆马铃薯和番茄主产区186个致病疫霉菌株.测定代表性菌株在不同培养基上的菌落生长和产孢量.结果表明,致病疫霉在RSA上生长最快,RA和RSB次之;在RSB上产孢最多,RTA次之.

  3. Phytophthora sojae: Diversity among and within Populations

    Science.gov (United States)

    Soybean production is increasing around the world and, to no surprise, so are the reports of soybean diseases caused by Phytophthora sojae, including Phytophthora seed, root, and stem rot. Phytophthora sojae is a diploid oomycete, which is homothallic and is limited to primarily one host: the soybe...

  4. Lofar Agro : gewasmonitoring en microklimaatmodellering ten behoeve van plaatsspecifieke beheersing van Phytophthora infestans : microklimaat en Phytophthora infectierisico's

    NARCIS (Netherlands)

    Kessel, G.J.T.

    2009-01-01

    In de zomer van 2008 is het microklimaat in aardappel op twee plaatsen in Nederland zeer gedetailleerd gemeten. Deze meetsessies hebben unieke datasets opgeleverd m.b.t. het microklimaat in een aardappelgewas en de invloed daarop van de hoeveelheid loofmassa, de plaats en de hoogte in het gewas

  5. Survey and analysis of microsatellites from transcript sequences in Phytophthora species: frequency, distribution, and potential as markers for the genus

    Directory of Open Access Journals (Sweden)

    Barreto Emiliano

    2006-09-01

    Full Text Available Abstract Background Members of the genus Phytophthora are notorious pathogens with world-wide distribution. The most devastating species include P. infestans, P. ramorum and P. sojae. In order to develop molecular methods for routinely characterizing their populations and to gain a better insight into the organization and evolution of their genomes, we used an in silico approach to survey and compare simple sequence repeats (SSRs in transcript sequences from these three species. We compared the occurrence, relative abundance, relative density and cross-species transferability of the SSRs in these oomycetes. Results The number of SSRs in oomycetes transcribed sequences is low and long SSRs are rare. The in silico transferability of SSRs among the Phytophthora species was analyzed for all sets generated, and primers were selected on the basis of similarity as possible candidates for transferability to other Phytophthora species. Sequences encoding putative pathogenicity factors from all three Phytophthora species were also surveyed for presence of SSRs. However, no correlation between gene function and SSR abundance was observed. The SSR survey results, and the primer pairs designed for all SSRs from the three species, were deposited in a public database. Conclusion In all cases the most common SSRs were trinucleotide repeat units with low repeat numbers. A proportion (7.5% of primers could be transferred with 90% similarity between at least two species of Phytophthora. This information represents a valuable source of molecular markers for use in population genetics, genetic mapping and strain fingerprinting studies of oomycetes, and illustrates how genomic databases can be exploited to generate data-mining filters for SSRs before experimental validation.

  6. Draft genome sequences of Phytophthora kernoviae and Phytophthora ramorum lineage EU2 from Scotland

    Directory of Open Access Journals (Sweden)

    Christine Sambles

    2015-12-01

    Full Text Available Newly discovered Phytophthora species include invasive pathogens that threaten trees and shrubs. We present draft genome assemblies for three isolates of Phytophthora kernoviae and one isolate of the EU2 lineage of Phytophthora ramorum, collected from outbreak sites in Scotland.

  7. Inhibition of Phytophthora parasitica and P. capsici by Silver Nanoparticles Synthesized Using Aqueous Extract of Artemisia absinthium.

    Science.gov (United States)

    Ali, Mohammad; Kim, Bosung; Belfield, Kevin D; Norman, David; Brennan, Mary; Ali, Gul Shad

    2015-09-01

    Application of nanoparticles for controlling plant pathogens is a rapidly emerging area in plant disease management, and nanoparticles synthesis methods that are economical and ecofriendly are extensively investigated. In this project, we investigated the potential of silver nanoparticles (AgNPs) synthesized with aqueous extract of Artemisia absinthium against several Phytophthora spp., which cause many economically important crop diseases. In in vitro dose-response tests conducted in microtiter plates, 10 µg ml⁻¹ of AgNPs inhibited mycelial growth of P. parasitica, P. infestans, P. palmivora, P. cinnamomi, P. tropicalis, P. capsici, and P. katsurae. Detailed in vitro dose-response analyses conducted with P. parasitica and P. capsici revealed that AgNPs synthesized with A. absinthium extract were highly potent (IC50: 2.1 to 8.3 µg ml⁻¹) and efficacious (100%) in inhibiting mycelial growth, zoospore germination, germ tube elongation, and zoospore production. Interestingly, AgNP treatment accelerated encystment of zoospores. Consistent with in vitro results, in planta experiments conducted in a greenhouse revealed that AgNP treatments prevented Phytophthora infection and improved plant survival. Moreover, AgNP in in planta experiments did not produce any adverse effects on plant growth. These investigations provide a simple and economical method for controlling Phytophthora with AgNP without affecting normal plant physiology.

  8. Vectors for fluorescent protein tagging in Phytophthora: tools for functional genomics and cell biology.

    Science.gov (United States)

    Ah-Fong, Audrey M V; Judelson, Howard S

    2011-09-01

    Fluorescent tagging has become the strategy of choice for examining the subcellular localisation of proteins. To develop a versatile community resource for this method in oomycetes, plasmids were constructed that allow the expression of either of four spectrally distinct proteins [cyan fluorescent protein (CFP), green fluorescent protein (GFP), yellow fluorescent protein (YFP), and mCherry], alone or fused at their N- or C-termini, to sequences of interest. Equivalent sets of plasmids were made using neomycin or hygromycin phosphotransferases (nptII, hpt) as selectable markers, to facilitate double-labelling and aid work in diverse species. The fluorescent proteins and drug-resistance markers were fused to transcriptional regulatory sequences from the oomycete Bremia lactucae, which are known to function in diverse oomycetes, although the promoter in the fluorescence cassette (ham34) can be replaced easily by a promoter of interest. The function of each plasmid was confirmed in Phytophthora infestans. Moreover, fusion proteins were generated using targeting sequences for the endoplasmic reticulum, Golgi, mitochondria, nuclei, and peroxisomes. Studies of the distribution of the fusions in mycelia and sporangia provided insight into cellular organisation at different stages of development. This toolbox of vectors should advance studies of gene function and cell biology in Phytophthora and other oomycetes. Copyright © 2011 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  9. Phytophthora genome sequences uncover evolutionary origins and mechanisms of pathogenesis

    NARCIS (Netherlands)

    Tyler, B.M.; Tripathy, S.; Zhang, X.; Dehal, P.; Jiang, R.H.Y.; Aerts, A.; Arredondo, F.D.; Baxter, L.; Bensasson, D.; Beynon, J.L.; Chapman, J.; Damasceno, C.M.B.; Dorrance, A.E.; Dou, D.; Dickerman, A.W.; Dubchak, I.L.; Garbelotto, M.; Gijzen, M.; Gordon, S.G.; Govers, F.; Grunwald, N.J.; Huang, W.; Ivors, K.L.; Jones, R.W.; Kamoun, S.; Krampis, K.; Lamour, K.H.; Lee, M.K.; McDonald, W.H.; Medina, M.; Meijer, H.J.G.; Nordberg, E.K.; Maclean, D.J.; Ospina-Giraldo, M.D.; Morris, P.F.; Phuntumart, V.; Putnam, N.H.; Rash, S.; Rose, J.K.C.; Sakihama, Y.; Salamov, A.A.; Savidor, A.; Scheuring, C.F.; Smith, B.M.; Sobral, B.W.S.; Terry, A.; Torto-Alalibo, T.A.; Win, J.; Xu, Z.; Zhang, H.; Grigoriev, I.V.; Rokhsar, D.S.; Boore, J.L.

    2006-01-01

    Draft genome sequences have been determined for the soybean pathogen Phytophthora sojae and the sudden oak death pathogen Phytophthora ramorum. Oömycetes such as these Phytophthora species share the kingdom Stramenopila with photosynthetic algae such as diatoms, and the presence of many Phytophthora

  10. Invloed van minerale olie op de bestrijding van Phytophthora infestans in pootaardappelen

    NARCIS (Netherlands)

    Spits, H.G.; Bus, C.B.

    2003-01-01

    De invloed van toevoeging van olie aan een fungicide op de werking van het fungicide is afhankelijk van het gebruikte fungicide. Gezamenlijk spuiten van olie en Aviso DF, Curzate M en mogelijk ook Acrobat, verhoogt de curatieve werking van deze fungiciden. Gezamenlijk spuiten van olie en Aviso DF, l

  11. The role of heterotrimeric G-proteins in development and virulence of Phytophthora infestans

    NARCIS (Netherlands)

    Latijnhouwers, M.

    2003-01-01

    Ever since the 1840s, when the disease first appeared in Europe and the United States, the threat of new outbreaks of late blight has terrified potato growers. In years when cool and wet weather conditions are prevailing, the disease is most destructive and nearly impossible to control.

  12. Laboratory methods of evaluating tomato resistance to late blight (Phytophthora infestans (Mont. de Bary

    Directory of Open Access Journals (Sweden)

    Elżbieta Horodecka

    2013-12-01

    Full Text Available The purpose of the presented investigations was to determine uniform laboratory methods of evaluating horizontal resistance of tomatoes to late blight. It was found that the best tests were infecting whole plants at the 5-leaf stage and infecting leaves removed from the middle part of the shoot. The best method of testing the resistance of fruit to infection was instilling a suspension of spores on the calyx with the sepals left in place.

  13. Methods of evaluating tomato susceptibility to late blight (Phytophthora infestans (Mont. de Bary under field conditions

    Directory of Open Access Journals (Sweden)

    Elżbieta Horodecka

    2013-12-01

    Full Text Available The purpose of the investigations carried out in 1983-1985 was to assess the usefulness of natural and artificial infections under field conditions for evaluating tomato resistance to late blight in Poland. It was found, that the degree of natural infection by this fungus was a better indicator of tomato resistance than the degree of artificial infection obtained under field conditions.

  14. Species tree estimation for the late blight pathogen, Phytophthora infestans, and close relatives

    Science.gov (United States)

    To better understand the evolutionary history of a group of organisms, an accurate estimate of the species phylogeny must be known. Traditionally, gene trees have served as a proxy for the species tree, although it was acknowledged early on that these trees represented different evolutionary process...

  15. Production of Phytophthora infestans-resistant potato (Solanum tuberosum) utilising Ensifer adhaerens OV14

    DEFF Research Database (Denmark)

    Wendt, Toni; Doohan, Fiona; Mullins, Ewen

    2012-01-01

    wish to generate novel varieties for a commercial purpose. The potential of non-Agrobacterium strains (Transbacter™) to modify a plant genome has previously been described. However, they are unlikely to be widely used without significant adjustments in transformation protocols in order to improve...... their gene transfer efficiencies. In this study we set out to identify alternative bacteria species that could (a) utilize vir genes for genetic transformation and (b) substitute for A. tumefaciens in existing transformation protocols, without a prerequisite for protocol modifications. To this end we...

  16. Phenotypic variation in Nordic populations of Phytophthora infestans in 2003

    DEFF Research Database (Denmark)

    Lehtinen, A; Hannukkala, A; Andersson, B;

    2008-01-01

    60% of the isolates were A1 mating type in each country. Both mating types were present in 40% of the fields where more than one isolate was tested, indicating strong potential for sexual reproduction. The proportion of metalaxyl-resistant isolates dropped to under 15% from the 60% observed...

  17. On the evolution of pesticide resistance in Phytophthora infestans : an experimental evolution approach

    NARCIS (Netherlands)

    Bosmans, S.

    2009-01-01

    Resistance to antimicrobial agents is a serious problem for both medicine and agriculture. The initial success of such toxins is due to absence of resistant genotypes in pathogen populations before treatment. The initial low frequency of resistance may be explained by negative pleiotropic effects of

  18. Effect of flumorph on F-actin dynamics in the potato late blight pathogen Phytophthora infestans

    NARCIS (Netherlands)

    Hua, C.; Kots, K.; Ketelaar, T.; Govers, F.; Meijer, H.J.G.

    2015-01-01

    Oomycetes are fungal-like pathogens that cause notorious diseases. Protecting crops against oomycetes requires regular spraying with chemicals, many of which with unknown mode of action. In the 1990’s, flumorph was identified as a novel crop protection agent. It was shown to inhibit the growth of oo

  19. The role of heterotrimeric G-proteins in development and virulence of Phytophthora infestans

    NARCIS (Netherlands)

    Latijnhouwers, M.

    2003-01-01

    Ever since the 1840s, when the disease first appeared in Europe and the United States, the threat of new outbreaks of late blight has terrified potato growers. In years when cool and wet weather conditions are prevailing, the disease is most destructive and nearly impossible to control. Dec

  20. Intracellular and extracellular phosphatidylinositol 3-phosphate produced by Phytophthora species is important for infection.

    Science.gov (United States)

    Lu, Shan; Chen, Linlin; Tao, Kai; Sun, Nannan; Wu, Yuren; Lu, Xiaoxue; Wang, Yuanchao; Dou, Daolong

    2013-09-01

    RxLR effectors produced by Phytophthora pathogens have been proposed to bind to phosphatidylinositol 3-phosphate (PtdIns(3)P) to mediate their translocation into host cells and/or to increase their stability in planta. Since the levels of PtdIns(3)P in plants are low, we examined whether Phytophthora species may produce PtdIns(3)P to promote infection. We observed that PtdIns(3)P-specific GFP biosensors could bind to P. parasitica and P. sojae hyphae during infection of Nicotiana benthamiana leaves transiently secreting the biosensors, suggesting that the hyphae exposed PtdIns(3)P on their plasma membrane and/or secreted PtdIns(3)P. Silencing of the phosphatidylinositol 3-kinases (PI3K) genes, treatment with LY294002, or expression of PtdIns(3)P-binding proteins by P. sojae reduced the virulence of the pathogen on soybean, indicating that pathogen-synthesized PtdIns(3)P was required for full virulence. Secretion of PtdIns(3)P-binding proteins or of a PI3P-5-kinase by N. benthamiana leaves significantly increased the level of resistance to infection by P. parasitica and P. capsici. Together, our results support the hypothesis that Phytophthora species produce external PtdIns(3)P to aid in infection, such as to promote entry of RxLR effectors into host cells. Our results derived from P. sojae RxLR effector Avr1b confirm that both the N-terminus and the C-terminus of this effector can bind PtdIns(3)P.

  1. Screening Phytophthora rubi for fungicide resistance

    Science.gov (United States)

    Preliminary results from the survey for fungicide resistance in Phytophthora were reported at the 2016 Washington Small Fruit Conference. Phytophthora was isolated from diseased plants in 28 red raspberry fields and tested against mefenoxam, the active ingredient of Ridomil. Most isolates were ident...

  2. Impregnated netting slows infestation by Triatoma infestans.

    Science.gov (United States)

    Levy, Michael Z; Quíspe-Machaca, Victor R; Ylla-Velasquez, Jose L; Waller, Lance A; Richards, Jean M; Rath, Bruno; Borrini-Mayori, Katty; del Carpio, Juan G Cornejo; Cordova-Benzaquen, Eleazar; McKenzie, F Ellis; Wirtz, Robert A; Maguire, James H; Gilman, Robert H; Bern, Caryn

    2008-10-01

    We used sentinel animal enclosures to measure the rate of infestation by the Chagas disease vector, Triatoma infestans, in an urban community of Arequipa, Peru, and to evaluate the effect of deltamethrin-impregnated netting on that rate. Impregnated netting decreased the rate of infestation of sentinel enclosures (rate ratio, 0.23; 95% confidence interval, 0.13-0.38; P < 0.001), controlling for the density of surrounding vector populations and the distance of these to the sentinel enclosures. Most migrant insects were early-stage nymphs, which are less likely to carry the parasitic agent of Chagas disease, Trypanosoma cruzi. Spread of the vector in the city therefore likely precedes spread of the parasite. Netting was particularly effective against adult insects and late-stage nymphs; taking into account population structure, netting decreased the reproductive value of migrant populations from 443.6 to 40.5. Impregnated netting can slow the spread of T. infestans and is a potentially valuable tool in the control of Chagas disease.

  3. Quantification of induced resistance against Phytophthora species expressing GFP as a vital marker: beta-aminobutyric acid but not BTH protects potato and Arabidopsis from infection.

    Science.gov (United States)

    Si-Ammour, Azeddine; Mauch-Mani, Brigitte; Mauch, Felix

    2003-07-01

    SUMMARY Induced resistance was studied in the model pathosystem Arabidopsis-Phytophthora brassicae (formerly P. porri) in comparison with the agronomically important late blight disease of potato caused by Phytophthora infestans. For the quantification of disease progress, both Phytophthora species were transformed with the vector p34GFN carrying the selectable marker gene neomycine phosphotransferase (nptII) and the reporter gene green fluorescent protein (gfp). Eighty five per cent of the transformants of P. brassicae and P. infestans constitutively expressed GFP at high levels at all developmental stages both in vitro and in planta. Transformants with high GFP expression and normal in vitro growth and virulence were selected to quantify pathogen growth by measuring the in planta emitted GFP fluorescence. This non-destructive monitoring of the infection process was applied to analyse the efficacy of two chemical inducers of disease resistance, a functional SA-analogue, benzothiadiazole (BTH), and beta-aminobutyric acid (BABA) which is involved in priming mechanisms of unknown nature. BABA pre-treatment (300 microm) via soil drench applied 24 h before inoculation completely protected the susceptible Arabidopsis accession Landsberg erecta (Ler) from infection with P. brassicae. A similar treatment with BTH (330 microm) did not induce resistance. Spraying the susceptible potato cultivar Bintje with BABA (1 mm) 2 days before inoculation resulted in a phenocopy of the incompatible interaction shown by the resistant potato cultivar Matilda while BTH (1.5 mm) did not protect Bintje from severe infection. Thus, in both pathosystems, the mechanisms of induced resistance appeared to be similar, suggesting that the Arabidopsis-P. brassicae pathosystem is a promising model for the molecular analysis of induced resistance mechanisms of potato against the late blight disease.

  4. End-effector microprocessor

    Science.gov (United States)

    Doggett, William R.

    1992-01-01

    The topics are presented in viewgraph form and include: automated structures assembly facility current control hierarchy; automated structures assembly facility purposed control hierarchy; end-effector software state transition diagram; block diagram for ideal install composite; and conclusions.

  5. PROTEÍNAS ANTIFÚNGICAS CONTRA P. INFESTANS EN LOS ESPACIOS INTERCELULARES DE HOJAS DE TOMATE (Lycopersicon esculentum cerasiforme POSIBLES DEFENSINAS DE PLANTAS

    Directory of Open Access Journals (Sweden)

    Luz Dary Riaño

    2008-03-01

    Full Text Available Se aislaron y caracterizaron parcialmente proteínas antifúngicas de los espacios intercelulares de hojas de tomate Lycopersicon esculentum cerasiforme, variedad que ha mostrado resistencia en campo a Phytophthora Infestans; se observó quedespués de inoculación con el patógeno dichas proteínas se acumularon sistémicamente en la planta. Las proteínas identificadasmostraron características de Defensinas de plantas, una nueva familia de proteínas con bajo peso molecular, carga positiva a pH fisiológico y actividad antifúngica evaluada in vitro contra P. infestans.Los análisis electroforéticos en geles de poliacrilamida con SDS-Tricina en condiciones reductoras y no reductoras, sugirieron que están asociadas en trímeros y tetrámeros y poseen pesos moleculares de 5,2 kDa.

  6. Agro-transformation and evaluation of resistance to Phytophthora infestansin Solanum tuberosumL. variety Désirée

    Directory of Open Access Journals (Sweden)

    Jeanette Orbegozo

    2014-03-01

    Full Text Available The Oomycete Phytophthora infestans (Mont. de Bary, the causal agent of the disease known as late blight, is primarily responsible for the decreased in production performance and potato crops worldwide. The integration of the complete Rgenes sequences in the potato genome using Agro-transformation appears an alternative to be considered in the fight against this pathogen. The Rpi-blb2 gene (Rgene from the wild species Solanum bulbocastanumDunal shows a broad resistance to isolates ofP. infestans,making it an important candidate for plant breeding studies. This paper reports the integration of the Rpi-blb2gene into potato var. Désirée genome by Agrobacterium tumefaciens- mediated transformation system, the molecular characterization of 29 events transformed and whole plant infection with isolate POX67 of P. infestansfrom Peru. Désirée events [Rpi-blb2] 4 and Désirée [Rpi-blb2] 30, showed a substantial resistance to P. infestansinfection confirming complete transfer of the Rpi-blb2gene from a wild species to a cultivated species by genetic transformation.

  7. Linkage relationships among multiple QTL for horticultural traits and late blight (P. infestans) resistance on chromosome 5 introgressed from wild tomato Solanum habrochaites.

    Science.gov (United States)

    Haggard, J Erron; Johnson, Emily B; St Clair, Dina A

    2013-12-09

    When the allele of a wild species at a quantitative trait locus (QTL) conferring a desirable trait is introduced into cultivated species, undesirable effects on other traits may occur. These negative phenotypic effects may result from the presence of wild alleles at other closely linked loci that are transferred along with the desired QTL allele (i.e., linkage drag) and/or from pleiotropic effects of the desired allele. Previously, a QTL for resistance to Phytophthora infestans on chromosome 5 of Solanum habrochaites was mapped and introgressed into cultivated tomato (S. lycopersicum). Near-isogenic lines (NILs) were generated and used for fine-mapping of this resistance QTL, which revealed coincident or linked QTL with undesirable effects on yield, maturity, fruit size, and plant architecture traits. Subsequent higher-resolution mapping with chromosome 5 sub-NILs revealed the presence of multiple P. infestans resistance QTL within this 12.3 cM region. In our present study, these sub-NILs were also evaluated for 17 horticultural traits, including yield, maturity, fruit size and shape, fruit quality, and plant architecture traits in replicated field experiments over the course of two years. Each previously detected single horticultural trait QTL fractionated into two or more QTL. A total of 41 QTL were detected across all traits, with ∼30% exhibiting significant QTL × environment interactions. Colocation of QTL for multiple traits suggests either pleiotropy or tightly linked genes control these traits. The complex genetic architecture of horticultural and P. infestans resistance trait QTL within this S. habrochaites region of chromosome 5 presents challenges and opportunities for breeding efforts in cultivated tomato.

  8. Genome sequences of two Phytophthora species responsible for Sudden Oak Death and Soybean Root Rot provide novel insights into their evolutionary origins and mechanisms of pathogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Tyler, Brett M.; Tripathi, Sucheta; Aerts, Andrea; Bensasson, Douda; Dehal, Paramvir; Dubchak, Inna; Garbelotto, Matteo; Gijzen, Mark; Huang, Wayne; Ivors, Kelly; Jiang, Rays; Kamoun, Sophien; Krampis, Konstantinos; Lamour, Kurt; McDonald, Hayes; Medina, Monica; Morris, Paul; Putnam, Nik; Rash, Sam; Salamov, Asaf; Smith, Brian; Smith, Joe; Terry, Astrid; Torto, Trudy; Grigoriev, Igor; Rokhsar, Daniel; Boore, Jeffrey

    2005-12-01

    The approximately 60 species of Phytophthora are all destructive pathogens, causing rots of roots, stems, leaves and fruits of a wide range of agriculturally and ornamentally important plants (1). Some species, such as P. cinnamomi, P. parasitica and P. cactorum, each attack hundreds of different plant host species, whereas others are more restricted. Some of the crops where Phytophthora infections cause the greatest financial losses include potato, soybean, tomato, alfalfa, tobacco, peppers, cucurbits, pineapple, strawberry, raspberry and a wide range of perennial tree crops, especially citrus, avocado, almonds, walnuts, apples and cocoa, and they also heavily affect the ornamental, nursery and forestry industries. The economic damage overall to crops in the United States by Phytophthora species is estimated in the tens of billions of dollars, including the costs of control measures, and worldwide it is many times this amount (1). In the northern midwest of the U.S., P. sojae causes $200 million in annual losses to soybean alone, and worldwide causes around $1-2 billion in losses per year. P. infestans infections resulted in the Irish potato famine last century and continues to be a difficult and worsening problem for potato and tomato growers worldwide, with worldwide costs estimated at $5 billion per year.

  9. Pathogenic diversity of Phytophthora sojae and breeding strategies to develop Phytophthora-resistant soybeans

    Science.gov (United States)

    Phytophthora stem and root rot disease, caused by Phytophthora sojae, is one of the most destructive diseases of soybean (Glycine max (L.) Merr.), and has been increasing in several soybean-producing areas around the world. This disease induces serious limitations on soybean production, with yield l...

  10. Phytophthora Database: A forensic database supporting the identification and monitoring of Phytophthora

    Science.gov (United States)

    Due to their high virulence and ability to spread rapidly, Phytophthora species represent a serious threat to agricultural production and ecological systems. Many novel Phytophthora species have been reported in recent years, indicative of our limited understanding of the ecology and diversity of Ph...

  11. Phytophthora rotråte i juletrefelt

    DEFF Research Database (Denmark)

    Talgø, Venche; Thomsen, Iben Margrete

    2015-01-01

    Phytophthora rotråte forårsaket av ulike arter av Phytophthora er et stort problem i juletreproduksjonen iUSA. I Norge er det også rapportert om flere tilfeller av skade på grunn av Phytophthora både i juletrær og klippegrønt, men så langt ikke i Danmark. I begge landene er flere arter av...... Phytophthora funnet på treaktige vekster i grøntanlegg. Vi har også sett en urovekkende spredning av Phytophthora til løvtrær i bynære skoger, vassdrag og naturområder det siste tiåret, spesielt i Norge. Både i Norge og Danmark har vi undersøkt vann i eller like ved juletreplantinger og funnet flere...... Phytophthora-arter, så dette er en skadegjører juletredyrkere må være på vakt overfor...

  12. Identification of cell wall-associated proteins from Phytophthora ramorum

    NARCIS (Netherlands)

    Meijer, H.J.G.; Vondervoort, van de P.J.I.; Yin, Q.Y.; Koster, de C.G.; Klis, F.M.; Govers, F.; Groot, de P.W.J.

    2006-01-01

    The oomycete genus Phytophthora comprises a large group of fungal-like plant pathogens. Two Phytophthora genomes recently have been sequenced; one of them is the genome of Phytophthora ramorum, the causal agent of sudden oak death. During plant infection, extracellular proteins, either soluble secre

  13. Identification of cell wall-associated proteins from Phytophthora ramorum

    NARCIS (Netherlands)

    Meijer, H.J.G.; Vondervoort, van de P.J.I.; Yin, Q.Y.; Koster, de C.G.; Klis, F.M.; Govers, F.; Groot, de P.W.J.

    2006-01-01

    The oomycete genus Phytophthora comprises a large group of fungal-like plant pathogens. Two Phytophthora genomes recently have been sequenced; one of them is the genome of Phytophthora ramorum, the causal agent of sudden oak death. During plant infection, extracellular proteins, either soluble

  14. Prospects for advanced late blight resistance breeding in potato

    Science.gov (United States)

    The potato late blight pathogen, Phytophthora infestans, is able to rapidly evolve to overcome resistance genes. The pathogen accomplishes this by secreting an arsenal of proteins, termed effectors, that function to modify host cells. Although hundreds of candidate effectors have been identified in ...

  15. Molecular determinants of pathogen recognition and defense elicitation in potato

    Science.gov (United States)

    The potato late blight pathogen, Phytophthora infestans, is able to rapidly evolve to overcome resistance genes. The pathogen accomplishes this by secreting an arsenal of proteins, termed effectors, that function to modify host cells. Although hundreds of candidate effectors have been identified in ...

  16. Presencia del Triatoma infestans en la ciudad de Lima

    Directory of Open Access Journals (Sweden)

    Abelardo Tejada

    1958-12-01

    Full Text Available 1 . Ha sido descubierto un foco del Triatoma infestans dentro de la zona urbana de la ciudad de Lima, verificándose su presencia en 10 viviendas de un modesto barrio. En tales casas fueron capturados un total de 99 especímenes del referido insecto, entre adultos y ninfas, así como 148 huevos sin eclosionar. 2. El examen del contenido intestinal y las heces en 68 de los triatomas capturados fue negativo para Trypanosoma cruzi. 3. Se supone que este nuevo foco se haya originado a partir de la región Sur del Perú, donde existen muchas localidades infestadas por el T. infestans. 4. Esta sería la primera vez que se verifica la presencia del T. infestans en la ciudad de Lima.

  17. Diagnostics of Tree Diseases Caused by Phytophthora austrocedri Species.

    Science.gov (United States)

    Mulholland, Vincent; Elliot, Matthew; Green, Sarah

    2015-01-01

    We present methods for the detection and quantification of four Phytophthora species which are pathogenic on trees; Phytophthora ramorum, Phytophthora kernoviae, Phytophthora lateralis, and Phytophthora austrocedri. Nucleic acid extraction methods are presented for phloem tissue from trees, soil, and pure cultures on agar plates. Real-time PCR methods are presented and include primer and probe sets for each species, general advice on real-time PCR setup and data analysis. A method for sequence-based identification, useful for pure cultures, is also included.

  18. The age of effectors

    NARCIS (Netherlands)

    Gibriel, Hesham A.Y.; Thomma, Bart P.H.J.; Seidl, Michael F.

    2016-01-01

    Microbial pathogens cause devastating diseases on economically and ecologically important plant species, threatening global food security, and causing billions of dollars of losses annually. During the infection process, pathogens secrete so-called effectors that support host colonization, often

  19. 75 FR 44936 - Notice of Request for Extension of Approval of an Information Collection; Phytophthora Ramorum...

    Science.gov (United States)

    2010-07-30

    ...; Phytophthora Ramorum; Quarantine and Regulations AGENCY: Animal and Plant Health Inspection Service, USDA... regulations for the interstate movement of regulated articles to prevent the spread of Phytophthora ramorum... of Phytophthora ramorum, contact Mr. Prakash Hebbar, Program Manager, Emergency and Domestic...

  20. Biological activity of Schinus molle on Triatoma infestans.

    Science.gov (United States)

    Ferrero, A A; Werdin González, J O; Sánchez Chopa, C

    2006-07-01

    Hexanic extracts from leaves and fruits of Schinus molle were tested for repellent and insecticidal properties against first instar nymphs and eggs of Triatoma infestans, the vector of Chagas' disease. Leaf and fruit extracts were highly repellent for first nymphs. Fruit extracts had also ovicidal activity.

  1. Mitochondrial genome sequences and comparative genomics ofPhytophthora ramorum and P. sojae

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Frank N.; Douda, Bensasson; Tyler, Brett M.; Boore,Jeffrey L.

    2007-01-01

    The complete sequences of the mitochondrial genomes of theoomycetes of Phytophthora ramorum and P. sojae were determined during thecourse of their complete nuclear genome sequencing (Tyler, et al. 2006).Both are circular, with sizes of 39,314 bp for P. ramorum and 42,975 bpfor P. sojae. Each contains a total of 37 identifiable protein-encodinggenes, 25 or 26 tRNAs (P. sojae and P. ramorum, respectively)specifying19 amino acids, and a variable number of ORFs (7 for P. ramorum and 12for P. sojae) which are potentially additional functional genes.Non-coding regions comprise approximately 11.5 percent and 18.4 percentof the genomes of P. ramorum and P. sojae, respectively. Relative to P.sojae, there is an inverted repeat of 1,150 bp in P. ramorum thatincludes an unassigned unique ORF, a tRNA gene, and adjacent non-codingsequences, but otherwise the gene order in both species is identical.Comparisons of these genomes with published sequences of the P. infestansmitochondrial genome reveals a number of similarities, but the gene orderin P. infestans differs in two adjacent locations due to inversions.Sequence alignments of the three genomes indicated sequence conservationranging from 75 to 85 percent and that specific regions were morevariable than others.

  2. High affinity recognition of a Phytophthora protein by Arabidopsis via an RGD motif.

    Science.gov (United States)

    Senchou, V; Weide, R; Carrasco, A; Bouyssou, H; Pont-Lezica, R; Govers, F; Canut, H

    2004-02-01

    The RGD tripeptide sequence, a cell adhesion motif present in several extracellular matrix proteins of mammalians, is involved in numerous plant processes. In plant-pathogen interactions, the RGD motif is believed to reduce plant defence responses by disrupting adhesions between the cell wall and plasma membrane. Photoaffinity cross-linking of [125I]-azido-RGD heptapeptide in the presence of purified plasma membrane vesicles of Arabidopsis thaliana led to label incorporation into a single protein with an apparent molecular mass of 80 kDa. Incorporation could be prevented by excess RGD peptides, but also by the IPI-O protein, an RGD-containing protein secreted by the oomycete plant pathogen Phytophthora infestans. Hydrophobic cluster analysis revealed that the RGD motif of IPI-O (positions 53-56) is readily accessible for interactions. Single amino acid mutations in the RGD motif in IPI-O (of Asp56 into Glu or Ala) resulted in the loss of protection of the 80-kDa protein from labelling. Thus, the interaction between the two proteins is mediated through RGD recognition and the 80-kDa RGD-binding protein has the characteristics of a receptor for IPI-O. The IPI-O protein also disrupted cell wall-plasma membrane adhesions in plasmolysed A. thaliana cells, whereas IPI-O proteins mutated in the RGD motif (D56A and D56E) did not.

  3. Bud Rot Caused by Phytophthora palmivora: A Destructive Emerging Disease of Oil Palm.

    Science.gov (United States)

    Torres, G A; Sarria, G A; Martinez, G; Varon, F; Drenth, A; Guest, D I

    2016-04-01

    Oomycetes from the genus Phytophthora are among the most important plant pathogens in agriculture. Epidemics caused by P. infestans precipitated the great Irish famine and had a major impact on society and human history. In the tropics, P. palmivora is a pathogen of many plant species including cacao (Theobroma cacao), citrus (Citrus sp.), durian (Durio zibethines), jackfruit (Artrocarpus heterophyllus), rubber (Hevea brasiliensis), and several palm species including coconut (Cocos nucifera), and the African oil palm (Elaeis guineensis) as determined recently. The first localized epidemics of bud rot in oil palm in Colombia were reported in 1964. However, recent epidemics of bud rot have destroyed more than 70,000 ha of oil palm in the Western and Central oil palm growing regions of Colombia. The agricultural, social, and economic implications of these outbreaks have been significant in Colombia. Identification of the pathogen after 100 years of investigating the disease in the world enabled further understanding of infection, expression of a range of symptoms, and epidemiology of the disease. This review examines the identification of P. palmivora as the cause of bud rot in Colombia, its epidemiology, and discusses the importance of P. palmivora as a major threat to oil palm plantings globally.

  4. Phytophthora porri in leek: epidemiology and resistance.

    NARCIS (Netherlands)

    Smilde, W.D.

    1996-01-01

    In winter, Phytophthora porri is an important pathogen of leek ( Allium porrum L.) in the Netherlands. The fungus survives the crop-free period in summer by oospores in soil, and infects the leaves in autumn. Field studies indicated that dispersal by rain splash is crucial for initiation of an epid

  5. Hot spots of Phytophthora in commercial nurseries

    Science.gov (United States)

    Corina Junker; Patrick Goff; Stefan Wagner; Sabine Werres

    2017-01-01

    Studies have shown that nurseries are an important source for the spread of Phytophthora. Most surveys and studies focusing on the epidemiology of these pathogens in nurseries are based on sampling of symptomatic plants or on samples like water of different sources used for irrigation. There is little knowledge, however, on the survival and...

  6. Phytophthora speelt verstoppertje bij NFT aardbei

    NARCIS (Netherlands)

    Evenhuis, B.; Verhoeven, J.T.W.

    2011-01-01

    Aardbeitelers worden 'blij' gemaakt met Phytophthora cactorum in hun gewas, terwijl ze daar niet op zitten te wachten. Onderzoekers worden teleurgesteld omdat infectie uitblijft terwijl ze er alles aan doen om aantasting te krijgen. Dat hindert ze bij het uitvinden wat het ontsmettingseffect is van

  7. Phytophthora Genome Sequences Uncover Evolutionary Origins and Mechanisms of Pathogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Lamour, Kurt H [ORNL; McDonald, W Hayes [ORNL; Savidor, Alon [ORNL

    2006-01-01

    Genome sequences of the soybean pathogen, Phytophthora sojae, and the sudden oak death pathogen, Phytophthora ramorum, suggest a photosynthetic past and reveal recent massive expansion and diversification of potential pathogenicity gene families. Abstract: Draft genome sequences of the soybean pathogen, Phytophthora sojae, and the sudden oak death pathogen, Phytophthora ramorum, have been determined. O mycetes such as these Phytophthora species share the kingdom Stramenopila with photosynthetic algae such as diatoms and the presence of many Phytophthora genes of probable phototroph origin support a photosynthetic ancestry for the stramenopiles. Comparison of the two species' genomes reveals a rapid expansion and diversification of many protein families associated with plant infection such as hydrolases, ABC transporters, protein toxins, proteinase inhibitors and, in particular, a superfamily of 700 proteins with similarity to known o mycete avirulence genes.

  8. Screening of antagonistic actinomycetic strains and their inhibitions against Phytophthora in festans%致病疫霉拮抗放线菌的筛选及抑菌作用初步研究

    Institute of Scientific and Technical Information of China (English)

    刘月; 蒋继志; 郭俊亭; 郭文; 李丽艳

    2012-01-01

    为获得对致病疫霉具有显著且稳定拮抗作用的放线菌,利用对峙培养法和滤纸片法测定了从土壤中分离纯化出的放线菌活体及其发酵液对致病疫霉生长的抑制作用,并对其中抑菌效果显著的Sy11菌株的抑菌方式、对致病疫霉的感应性、传代稳定性以及对致病疫霉菌体形态的影响进行了初步研究.结果表明,分离纯化出的74株放线菌中有17株对致病疫霉具有拮抗作用,但其发酵液对致病疫霉均无抑制作用;Sy11菌株只有感应到致病疫霉存在时才分泌对致病疫霉的抑菌物质;连续传代25次后,Sy11菌株的抑制率仍然保持在81%以上;Sy11菌株可导致致病疫霉菌丝体严重变形,但只是抑制其生长,并未杀死致病疫霉.这些结果表明,Sy11菌株在防治马铃薯晚疫病方面具有较大的应用潜力.%In order to obtain highly effective and stably antagonistic actinomycetes strains a-gainst Phytophthora infestans, the inhibitory effects of living and fermentation filtrates of actinomycetic strains isolated from vegetable-grown soil on mycelial growth of P. infestans were detected with dual-culture and filter paper methods, and inhibitory manner, response to P. infestans, stability of inhibition effect after continuous passage culture, and influence on P. infestans mycelial morphological character were investigated in this experiment. The results showed that 17 of 74 strains were evidently antagonistic to P. infestans, but all of fermentation liquors of 17 strains were not antagonistic to P. infestans. Syll strain had response to P. infestans, and could produce and secrete some substances inhibiting P. infestans. After continuous passage culture for 25 times, the inhibitory rate of Syll strain on P. infestans still maintained over 81%. Syll strain could cause to lose original sketch and structure seriously. However, Syll strain just inhibited P. infestans but did not kill it. These results indicated

  9. Phytophthora Genome Sequences Uncover Evolutionary Origins and Mechanisms of Pathogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Tyler, Brett M.; Tripathy, Sucheta; Zhang, Xuemin; Dehal, Paramvir; Jiang, Rays H. Y.; Aerts, Andrea; Arredondo, Felipe D.; Baxter, Laura; Bensasson, Douda; Beynon, JIm L.; Chapman, Jarrod; Damasceno, Cynthia M. B.; Dorrance, Anne E.; Dou, Daolong; Dickerman, Allan W.; Dubchak, Inna L.; Garbelotto, Matteo; Gijzen, Mark; Gordon, Stuart G.; Govers, Francine; Grunwald, NIklaus J.; Huang, Wayne; Ivors, Kelly L.; Jones, Richard W.; Kamoun, Sophien; Krampis, Konstantinos; Lamour, Kurt H.; Lee, Mi-Kyung; McDonald, W. Hayes; Medina, Monica; Meijer, Harold J. G.; Nordberg, Erik K.; Maclean, Donald J.; Ospina-Giraldo, Manuel D.; Morris, Paul F.; Phuntumart, Vipaporn; Putnam, Nicholas J.; Rash, Sam; Rose, Jocelyn K. C.; Sakihama, Yasuko; Salamov, Asaf A.; Savidor, Alon; Scheuring, Chantel F.; Smith, Brian M.; Sobral, Bruno W. S.; Terry, Astrid; Torto-Alalibo, Trudy A.; Win, Joe; Xu, Zhanyou; Zhang, Hongbin; Grigoriev, Igor V.; Rokhsar, Daniel S.; Boore, Jeffrey L.

    2006-04-17

    Draft genome sequences have been determined for the soybean pathogen Phytophthora sojae and the sudden oak death pathogen Phytophthora ramorum. Oömycetes such as these Phytophthora species share the kingdom Stramenopila with photosynthetic algae such as diatoms, and the presence of many Phytophthora genes of probable phototroph origin supports a photosynthetic ancestry for the stramenopiles. Comparison of the two species' genomes reveals a rapid expansion and diversification of many protein families associated with plant infection such as hydrolases, ABC transporters, protein toxins, proteinase inhibitors, and, in particular, a superfamily of 700 proteins with similarity to known oömycete avirulence genes.

  10. Effector glycosyltransferases in Legionella

    Directory of Open Access Journals (Sweden)

    Yury eBelyi

    2011-04-01

    Full Text Available Legionella causes severe pneumonia in humans. The pathogen produces an array of effectors, which interfere with host cell functions. Among them are the glucosyltransferases Lgt1, Lgt2 and Lgt3 from L. pneumophila. Lgt1 and Lgt2 are produced predominately in the post-exponential phase of bacterial growth, while synthesis of Lgt3 is induced mainly in the lag-phase before intracellular replication of bacteria starts. Lgt glucosyltransferases are structurally similar to clostridial glucosylating toxins. The enzymes use UDP-glucose as a donor substrate and modify eukaryotic elongation factor eEF1A at serine-53. This modification results in inhibition of protein synthesis and death of target cells. In addition to Lgts, Legionella genomes disclose several genes, coding for effector proteins likely to possess glycosyltransferase activities, including SetA, which influences vesicular trafficking in the yeast model system and displays tropism for late endosomal/lysosomal compartments of mammalian cells. This review mainly discusses recent results on the structure-function relationship of Lgt glucosyltransferases.

  11. Ecología urbana de Triatoma infestans en Argentina: asociación entre Triatoma infestans y palomares Triatoma infestans urban ecology in Argentina: association between Triatoma infestans and pigeon cotes

    Directory of Open Access Journals (Sweden)

    Silvana L. Vallvé

    1995-06-01

    Full Text Available Estudio se realizó en una área urbana de la Capital de la Provincia de San Juan, Argentina, en un barrio de 768 apartamentos distribuidos en edificios de 3 y 7 pisos que rodean una bodega central abandonada. Se capturaron 329 ejemplares de Triatoma infestans, 293 en 4 terrazas de torres de 7 pisos y 36 en el interior de la bodega, associados con numerosas palomas que colomizaban estos sitios. Los insectos se refugiaban en el guano acumulado entre bloques de cemento que cubren las terrazas y en la bodega dentro de toneles en desuso. Se identificaron dos focos principales de vectores associados con densos palomares: un 81,5% del total de triatomas colectados se halló en una de las torres y un 11% en la bodega. A los 6 meses del tratamiento insecticida, resultaron positivas terrazas en las que previamente no se habia capturado T. infestans. El perfil alimentario de los triatomas muestra un predominio de ingestas simples sobre ave; en los edificios y en la bodega el 95% de los T. infestans analizados se alimentó sólo de ave; el resto fueron ingestas simples o dobles sobre humano, perro o gato. Ningún T. infestans presentó infección con Trypanosoma cruzi.Estudo realizado em local urbano da capital da Província de San Juan, Argentina, num bairro de 768 apartamentos distribuídos em prédios de 3 e 7 andares que cingem uma adega vinícola abandonada. Foram coletados 329 exemplares de Triatoma infestans, 293 em 4 terraços das torres de 7 andares e 36 no interior da adega, associados às numerosas pombas que colonizavam esses sítios. Os insetos refugiavam-se no excremento cumulado entre os blocos de cimento que cobrem os terraços e, na adega, dentro de tonéis fora de uso. Foram identificados dois focos principais de vetores, associados com densos pombais: 81,5% do total de triatomas coletados foram apanhados em uma das torres e 11% na adega. Após 6 meses de tratamento com inseticida, foram positivos os terraços onde anteriormente não se

  12. Susceptibility of common alder (Alnus glutinosa) seeds and seedlings to Phytophthora alni and other Phytophthora species

    Energy Technology Data Exchange (ETDEWEB)

    Haque, M. M.; Diez, J. J.

    2012-11-01

    Phytophthora alni is a highly destructive host specific pathogen to alders (Alnus spp.) spreading all over Europe. Recently this pathogen has been reported to cause diseases in common alder (Alnus glutinosa) in Spain. Seeds and seedlings of A. glutinosa were tested in vitro for their susceptibility to alder Phytophthora and other Phytophthora species. Isolates of P. alni ssp. alni, P. cinnamomi, P. citrophthora, P. nicotianae and P. palmivora were used in the experiments. Seeds and seedlings were inoculated with a zoospore suspension and uniform mycelial blocks of agar of the Phytophthora species. Susceptibility was calculated in terms of pathogen virulence on seed germination and seedling mortality 42 and 67 days after inoculation respectively. Seed germination and seedling mortality rates varied differently among the isolates used. Results implied that common alder and its seeds and seedlings are at risk to be infected by P. alni. In addition, other Phytophthora species are able to infect this kind of material showing their relative host non-specificity. This is one important finding concerning alder regeneration in infected areas, and the possibility of disease spread on this plant material. (Author) 42 refs.

  13. Two-axis angular effector

    Energy Technology Data Exchange (ETDEWEB)

    Vaughn, Mark R. (Albuquerque, NM); Robinett, III, Rush D. (Tijeras, NM); Phelan, John R. (Albuquerque, NM); Van Zuiden, Don M. (Albuquerque, NM)

    1997-01-21

    A new class of coplanar two-axis angular effectors. These effectors combine a two-axis rotational joint analogous to a Cardan joint with linear actuators in a manner to produce a wider range of rotational motion about both axes defined by the joint. This new class of effectors also allows design of robotic manipulators having very high strength and efficiency. These effectors are particularly suited for remote operation in unknown surroundings, because of their extraordinary versatility. An immediate application is to the problems which arise in nuclear waste remediation.

  14. Two-axis angular effector

    Energy Technology Data Exchange (ETDEWEB)

    Vaughn, M.R.; Robinett, R.D. III; Phelan, J.R.; Zuiden, D.M. Van

    1997-01-21

    A new class of coplanar two-axis angular effectors is described. These effectors combine a two-axis rotational joint analogous to a Cardan joint with linear actuators in a manner to produce a wider range of rotational motion about both axes defined by the joint. This new class of effectors also allows design of robotic manipulators having very high strength and efficiency. These effectors are particularly suited for remote operation in unknown surroundings, because of their extraordinary versatility. An immediate application is to the problems which arise in nuclear waste remediation. 11 figs.

  15. Urban ecology of Triatoma infestans in San Juan, Argentina

    Directory of Open Access Journals (Sweden)

    Silvana L Vallvé

    1996-08-01

    Full Text Available This study was performed in an urban neighborhood of the capital city of the province of San Juan, Argentina. Erected as a housing complex, the place consists of 768 flats distributed in buildings of three and seven floors each. A survey was carried out in 33% of the dwellings, enquiring about the number of Triatoma infestans found indoors, stage of the bug development - nymph or adult - and how these insects had entered their homes. Adult T.infestans were found on all floors; 163 people (64% had found them at least once, and 130 (51% several times. Dispersal flight seems to have been the main mechanism of infestation by adult bugs in this area, and a total of 51% of the surveyed inhabitants reported that the insects had flown into their flats.

  16. Secondary Kill Effect of Deltamethrin on Triatoma infestans

    Science.gov (United States)

    MALONEY, KATHLEEN M.; ANCCA-JUAREZ, JENNY; SALAZAR, RENZO; BORRINI-MAYORI, KATTY; PAMO-TITO, DANITZA; KEATING, JOSEPH A.; LEVY, MICHAEL Z.

    2012-01-01

    Control of the Chagas disease vector, Triatoma infestans, relies on the application of pyrethroid insecticides, especially deltamethrin. We performed laboratory studies to determine whether a T. infestans nymph that comes into contact with a deltamethrin-treated surface horizontally transfers the insecticide to subsequent triatomines. We found that a triatomine that walks on a deltamethrin-treated surface for a short period of time has the ability to transport the insecticide in concentrations sufficient to kill other triatomines with which it comes into contact. The effect was limited to high-density environments, and mortality as a result of secondary exposure was greater among second-instar nymphs compared with fifth-instar nymphs. Our results suggest that deltamethrin could be killing triatomines through both direct and indirect contact, although it remains unclear whether the phenomenon occurs in natural conditions. PMID:21845956

  17. Periurban Trypanosoma cruzi-infected Triatoma infestans, Arequipa, Peru.

    Science.gov (United States)

    Levy, Michael Zachary; Bowman, Natalie M; Kawai, Vivian; Waller, Lance A; Cornejo del Carpio, Juan Geny; Cordova Benzaquen, Eleazar; Gilman, Robert H; Bern, Caryn

    2006-09-01

    In Arequipa, Peru, vectorborne transmission of Chagas disease by Triatoma infestans has become an urban problem. We conducted an entomologic survey in a periurban community of Arequipa to identify risk factors for triatomine infestation and determinants of vector population densities. Of 374 households surveyed, triatomines were collected from 194 (52%), and Trypanosoma cruzi-carrying triatomines were collected from 72 (19.3%). Guinea pig pens were more likely than other animal enclosures to be infested and harbored 2.38x as many triatomines. Stacked brick and adobe enclosures were more likely to have triatomines, while wire mesh enclosures were protected against infestation. In human dwellings, only fully stuccoed rooms were protected against infestation. Spatially, households with triatomines were scattered, while households with T. cruzi-infected triatomines were clustered. Keeping small animals in wire mesh cages could facilitate control of T. infestans in this densely populated urban environment.

  18. Pathogenicity of Phytophthora isolates originating from several woody hosts in Bulgaria and Poland

    Directory of Open Access Journals (Sweden)

    Lyubenova Aneta B.

    2016-09-01

    Full Text Available Our aim was to examine the virulence of eight Phytophthora isolates belonging to three species (Phytophthora cryptogea, Phytophthora plurivora and Phytophthora quercina obtained from diverse European ecosystems (in Bulgaria, Poland and Germany towards three forest tree hosts – English oak (Quercus robur L., Turkey oak (Quercus cerris L. and European beech (Fagus sylvatica L..

  19. RESISTANCE AND RESISTANT LEVEL OF PHYTOPHTHORA INFESTANS TO METALAXYL IN CHONGQING%重庆地区马铃薯晚疫病菌(Phytophthora infestans)对甲霜灵抗性及抗性水平测定

    Institute of Scientific and Technical Information of China (English)

    毕朝位; 杜喜翠; 车兴壁; 马金成; 王中康

    2002-01-01

    2001年从北碚、云阳、开县、万州、巫溪和忠县等地采集马铃薯晚疫病病叶,共分离得94株致病疫霉.用生长速率法测定其对甲霜灵的抗性和抗性水平,结果表明:20.2%的菌株表现为抗性,11.7%的菌株表现为中抗,68.1%的菌株表现为敏感;以菌株PBB-1102为敏感对照,所测定的2株抗性菌株的抗性水平达106倍以上,各地菌株抗性表现与菌株来源地的施药水平密切相关,并对抗药性不同的地区提出了不同的用药策略.

  20. The Application of Advanced Biotechnology on the Study of Phytophthora infestans%现代生物技术在马铃薯晚疫病菌(Phytophthora infestans)研究中的应用

    Institute of Scientific and Technical Information of China (English)

    邵铁梅; 朱杰华; 郑秀银

    2002-01-01

    综述了同功酶、RFLP、PCR、RAPD、AFLP的基本原理及其在晚疫病菌研究中的应用.主要包括以下6方面:①绘制晚疫病菌的连锁图谱;②分析一个地区晚疫病菌的基因结构及其变化;③分析采自不同寄主的菌株基因结构的差异;④研究晚疫病菌的来源;⑤研究墨西哥以外地区A2交配型菌株的来源;⑥研究有性生殖的发生情况.同时还展望了现代生物技术在晚疫病菌研究中的发展方向,指出该研究领域国内与国外的差距及今后国内的研究方向.

  1. 番茄晚疫病菌(Phytophthora infestans)对甲霜灵的抗性测定及治理%Resistance of Phytophthora infestans to metalaxyl and the strategy for control

    Institute of Scientific and Technical Information of China (English)

    毕朝位; 王中康; 车兴壁

    2003-01-01

    2000~2001年连续3季从壁山、沙坝坝蔬菜基地采集番茄晚疫病病叶和病果,共分离得80株晚疫病菌.用生长速率法测定其对甲霜灵的抗性和抗性水平,结果有75.0%的菌株表现为抗性,13.8%的菌株表现为中抗,11.2%的菌株表现为敏感.以菌株TBS-2131为敏感对照,所测定的4株抗性菌株的抗性水平达5×104倍以上.此结果表明当地晚疫病菌抗性菌株已占优势,并且抗性水平已很高.同时有针对性地提出了防治番茄晚疫病的用药策略.

  2. 马铃薯晚疫病(Phytophthora infestans (Mont.) de Bary)的流行和防治研究%Study on epidemic and control of potato late blight(Phytophthora infestans (Mont.) de Bary)

    Institute of Scientific and Technical Information of China (English)

    杨韶勇; 曹克强

    2001-01-01

    Field trials were conducted in 1997 to evaluate crucial weather conditions for potato late blight epidemic. Two trials were performed to prove latent periods on different varieties and infection rate at Reckenholz.Sporangia were found on the leaflets if the accumulated temperature was above 2,346.5 degree-hours in the potato. Temperature is a very important factor for the epidemic of disease. The key condition for disease infection was a temperature over 10℃ and relative humidity of more than 90% in successive 6 hours. Rainfall played an important role for disease dispersal. Better disease controls were received by following PhytoPRE and CWC model in field trials.%1997年做了田间试验用来评价影响马铃薯晚疫病流行的关键天气条件.在Reckenholz做了2个试验研究晚疫病的潜伏期和侵染速率.结果表明,当累计有效积温达到2346.5℃@h时,孢子囊开始在马铃薯叶片出现.温度是影响晚疫病流行的重要因子.病害侵染的重要条件是温度超过10℃并且在连续6 h内空气相对湿度大于90%.降雨在病害传播中发挥了重要作用.根据PhytoPRE和CWC两个决策支持系统所采取的病害防治取得了较好的病害防治效果.

  3. Pathogens of potato (Solanum tuberosum L. tuber (Phytophtora infestans occurring in treatments with foliar fertilization

    Directory of Open Access Journals (Sweden)

    Bożena Cwalina-Ambroziak

    2012-10-01

    Full Text Available The paper presents the results of a three-year exact plot experiment (2008-2010 established in Bałcyny (NE Poland. Three potato cultivars were grown: medium-early ‘Adam’, medium-late ‘Pasja Pomorska’, and late ‘Ślęza’. The experimental factors were foliar fertilizers applied alone or in combination (Basfoliar 12-4-6, ADOB Mn, Solubor DF and two levels of soil mineral fertilization (N1P1K1-80 kg N × ha-1, 80 kg P × ha-1, 120 K × ha-1; N2P2K2-120 kg N × ha-1, 144 kg P × ha-1, 156 K × ha-1. The experimental materials comprised potato tubers. The symptoms of soft rot (Pectobacterium carotovorum subsp. carotovorum, late blight (Phytophthora infestans and dry rot (Fusarium spp. were evaluated in 5 kg potato samples, and were expressed as the percentage mass of infected tubers. The rates of common scab (Streptomyces scabies and black scurf (Rhizoctonia solani infection were estimated on 100 tubers collected randomly after harvest, according to a nine-point scale, and were presented as a percentage infection index. In the laboratory, fungi were isolated on PDA medium from potato tubers immediately after harvest and after five-month storage. The incidence of tuber diseases depended on potato cultivars affected. The severity of tuber diseases varied between treatments with two levels of NPK fertilization and foliar fertilization. The lowest number of Fusarium-infected tubers was obtained from treatments where three foliar fertilizers were applied in combination, which was confirmed by the lowest abundance of fungal isolates. More fungi were isolated from potato tubers after harvest than after storage, but pathogens were more frequently isolated from stored tubers. After harvest, the lowest number of pathogenic fungi was isolated from the tubers of cv. ‘Adam’ in the non-fertilized treatment, and after storage – from the tubers of the late cultivars in the treatment with three foliar fertilizers applied in combination.

  4. Phytophthora root rot resistance in soybean E00003

    Science.gov (United States)

    Phytophthora root rot (PRR), caused by the oomycete Phytophthora sojae, is a devastating disease in soybean production. Using resistant cultivars has been suggested as the best solution for disease management. Michigan elite soybean E00003 is resistant to P. sojae and has been used as a PRR resist...

  5. Host and habitat index for Phytophthora species in Oregon

    Science.gov (United States)

    Everett Hansen; Paul Reeser; Wendy Sutton; Laura. Sims

    2012-01-01

    In this contribution we compile existing records from available sources of reliably identified Phytophthora species from forests and forest trees in Oregon, USA. A searchable version of this information may be found in the Forest Phytophthoras of the World Disease Finder (select USA-Oregon). We have included isolations from soil and streams in...

  6. Forest Phytophthora diseases in the Americas: 2007 - 2010

    Science.gov (United States)

    S. J. Frankel; E. M. Hansen

    2011-01-01

    Recent findings, policy, regulation, and management relating to tree disease caused by Phytophthora species in wildlands and nurseries of North and South America are reviewed. These include the isolation of Phytophthora alni uniformis Brasier & S.A.Kirk in Alaska, and detection of population shifts in NA1, NA2 and EU1...

  7. Putting the Phytophthora infestans genome sequence at work: multiple novel avirulence and potato resistance gene candidates revealed

    NARCIS (Netherlands)

    Rietman, H.

    2011-01-01

    Individual variation in milk yield response to concentrate intake and
    milking interval length
    During the last century in the Netherlands milk production per cow has almost tripled.
    Accordingly, the amount of concentrates yearly fed per cow strongly increased.
    Furthermore, aut

  8. The effect of pyramiding Phytophthora infestans resistance genes R Pi-mcd1 and R Pi-ber in potato

    NARCIS (Netherlands)

    Tan, M.Y.A.; Hutten, R.C.B.; Visser, R.G.F.; Eck, van H.J.

    2010-01-01

    Despite efforts 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 stu

  9. Putting the Phytophthora infestans genome sequence at work: multiple novel avirulence and potato resistance gene candidates revealed

    NARCIS (Netherlands)

    Rietman, H.

    2011-01-01

    Individual variation in milk yield response to concentrate intake and
    milking interval length
    During the last century in the Netherlands milk production per cow has almost tripled.
    Accordingly, the amount of concentrates yearly fed per cow strongly increased.
    Furthermore,

  10. Putting the Phytophthora infestans genome sequence at work: multiple novel avirulence and potato resistance gene candidates revealed

    NARCIS (Netherlands)

    Rietman, H.

    2011-01-01

    Individual variation in milk yield response to concentrate intake and
    milking interval length
    During the last century in the Netherlands milk production per cow has almost tripled.
    Accordingly, the amount of concentrates yearly fed per cow strongly increased.
    Furthermore, aut

  11. Molecular profiling of the Phytophthora plurivora secretome: a step towards understanding the cross-talk between plant pathogenic oomycetes and their hosts.

    Science.gov (United States)

    Severino, Valeria; Farina, Annarita; Fleischmann, Frank; Dalio, Ronaldo J D; Di Maro, Antimo; Scognamiglio, Monica; Fiorentino, Antonio; Parente, Augusto; Osswald, Wolfgang; Chambery, Angela

    2014-01-01

    The understanding of molecular mechanisms underlying host-pathogen interactions in plant diseases is of crucial importance to gain insights on different virulence strategies of pathogens and unravel their role in plant immunity. Among plant pathogens, Phytophthora species are eliciting a growing interest for their considerable economical and environmental impact. Plant infection by Phytophthora phytopathogens is a complex process coordinated by a plethora of extracellular signals secreted by both host plants and pathogens. The characterization of the repertoire of effectors secreted by oomycetes has become an active area of research for deciphering molecular mechanisms responsible for host plants colonization and infection. Putative secreted proteins by Phytophthora species have been catalogued by applying high-throughput genome-based strategies and bioinformatic approaches. However, a comprehensive analysis of the effective secretome profile of Phytophthora is still lacking. Here, we report the first large-scale profiling of P. plurivora secretome using a shotgun LC-MS/MS strategy. To gain insight on the molecular signals underlying the cross-talk between plant pathogenic oomycetes and their host plants, we also investigate the quantitative changes of secreted protein following interaction of P. plurivora with the root exudate of Fagus sylvatica which is highly susceptible to the root pathogen. We show that besides known effectors, the expression and/or secretion levels of cell-wall-degrading enzymes were altered following the interaction with the host plant root exudate. In addition, a characterization of the F. sylvatica root exudate was performed by NMR and amino acid analysis, allowing the identification of the main released low-molecular weight components, including organic acids and free amino acids. This study provides important insights for deciphering the extracellular network involved in the highly susceptible P. plurivora-F. sylvatica interaction.

  12. Phytophthora-ID.org: A sequence-based Phytophthora identification tool

    Science.gov (United States)

    N.J. Grünwald; F.N. Martin; M.M. Larsen; C.M. Sullivan; C.M. Press; M.D. Coffey; E.M. Hansen; J.L. Parke

    2010-01-01

    Contemporary species identification relies strongly on sequence-based identification, yet resources for identification of many fungal and oomycete pathogens are rare. We developed two web-based, searchable databases for rapid identification of Phytophthora spp. based on sequencing of the internal transcribed spacer (ITS) or the cytochrome oxidase...

  13. Temperature effect upon blood consumption in Triatoma infestans

    Directory of Open Access Journals (Sweden)

    Silvia Catalá

    1992-12-01

    Full Text Available Different blood consumption speed was observed in Triatoma infestans - nymphs and adults - exposed to 12 degrees C and 28 degrees C. Exposure to optimal temperature (28 degrees C allows the insects to consume blood at a rate of 9% per day. Significative relationship between blood amount present in the promesenteron and consumed blood was found at 28 degrees. Consumption of blood was drastically reduced at the lowest temperature. Accordingly, lack of ovaric development, oviposition and mating behaviour was observed in insects kept at 12 degrees C. Relationship between laboratory and field observations are discussed.

  14. 广州地区茄疫病的发生及疫霉种鉴定%On the Occurrence and the Identification of Eggplant's Phytophthora Disease in Guangzhou Region

    Institute of Scientific and Technical Information of China (English)

    成家壮; 韦小燕

    2002-01-01

    1987~1999年,从广州地区茄的果实、茎、叶及根上分离得到疫霉菌,根据形态特征、培养性状及生理特性等方面研究结果,鉴定出4个种,其中以辣椒疫霉Phytophthora capsici Leon较为普遍,烟草疫霉P.nicotianae Van Breda de Haan次之, 掘氏疫霉P.drechsleri Tucker较少出现,致病疫霉P.infestans (Montagne) de Bary 仅见于春季;此外,种群分布与前作及不同季节有关.

  15. Genetic transformation of the plant pathogens Phytophthora capsici and Phytophthora parasitica.

    Science.gov (United States)

    Bailey, A M; Mena, G L; Herrera-Estrella, L

    1991-08-11

    Phytophthora capsici and P.parasitica were transformed to hygromycin B resistance using plasmids pCM54 and pHL1, which contain the bacterial hygromycin B phosphotransferase gene (hph) fused to promoter elements of the Ustilago maydis heat shock hsp70 gene. Enzymes Driselase and Novozyme 234 were used to generate protoplasts which were then transformed following exposure to plasmid DNA and polyethylene glycol 6000. Transformation frequencies of over 500 transformants per micrograms of DNA per 1 x 10(6) protoplasts were obtained. Plasmid pCM54 appears to be transmitted in Phytophthora spp. as an extra-chromosomal element through replication, as shown by Southern blot hybridization and by the loss of plasmid methylation. In addition, transformed strains retained their capacity of infecting Serrano pepper seedlings and Mc. Intosh apple fruits, the host plants for P.capsici and P.parasitica, respectively.

  16. Genetic transformation of the plant pathogens Phytophthora capsici and Phytophthora parasitica.

    OpenAIRE

    Bailey, A. M.; Mena, G L; Herrera-Estrella, L

    1991-01-01

    Phytophthora capsici and P.parasitica were transformed to hygromycin B resistance using plasmids pCM54 and pHL1, which contain the bacterial hygromycin B phosphotransferase gene (hph) fused to promoter elements of the Ustilago maydis heat shock hsp70 gene. Enzymes Driselase and Novozyme 234 were used to generate protoplasts which were then transformed following exposure to plasmid DNA and polyethylene glycol 6000. Transformation frequencies of over 500 transformants per micrograms of DNA per ...

  17. Evaluation of Watermelon Germplasm for Resistance to Phytophthora Blight Caused by Phytophthora capsici

    Directory of Open Access Journals (Sweden)

    Min-Jeong Kim

    2013-03-01

    Full Text Available This study was conducted to determine the Phytophthora rot resistance of 514 accessions of watermelon germplasm, Citrullus lanatus var lanatus. About 46% of the 514 accessions tested were collections from Uzbekistan, Turkey, China, U.S.A., and Ukraine. Phytophthora capsici was inoculated to 45-day-old watermelon seedlings by drenching with 5 ml of sporangial suspension (10⁶ sporangia/ml. At 7 days after inoculation, 21 accessions showed no disease symptoms while 291 accessions of susceptible watermelon germplasm showed more than 60.1% disease severity. A total of 510 accessions of watermelon germplasm showed significant disease symptoms and were rated as susceptible to highly susceptible 35 days after inoculation. The highly susceptible watermelon germplasm exhibited white fungal hyphae on the lesion or damping off with water-soaked and browning symptoms. One accession (IT032840 showed moderate resistance and two accessions (IT185446 and IT187904 were resistant to P. capsici. Results suggest that these two resistant germplasm can be used as a rootstock and as a source of resistance in breeding resistant watermelon varieties against Phytophthora.

  18. Biocontrol of Phytophthora Blight and Anthracnose in Pepper by Sequentially Selected Antagonistic Rhizobacteria against Phytophthora capsici

    Directory of Open Access Journals (Sweden)

    Mee Kyung Sang

    2013-06-01

    Full Text Available We previously developed a sequential screening procedure to select antagonistic bacterial strains against Phytophthora capsici in pepper plants. In this study, we used a modified screening procedure to select effective biocontrol strains against P. capsici; we evaluated the effect of selected strains on Phytophthora blight and anthracnose occurrence and fruit yield in pepper plants under field and plastic house conditions from 2007 to 2009. We selected four potential biocontrol strains (Pseudomonas otitidis YJR27, P. putida YJR92, Tsukamurella tyrosinosolvens YJR102, and Novosphingobium capsulatum YJR107 among 239 bacterial strains. In the 3-year field tests, all the selected strains significantly (P < 0.05 reduced Phytophthora blight without influencing rhizosphere microbial populations; they showed similar or better levels of disease suppressions than in metalaxyl treatment in the 2007 and 2009 tests, but not in the 2008 test. In the 2-year plastic house tests, all the selected strains significantly (P < 0.05 reduced anthracnose incidence in at least one of the test years, but their biocontrol activities were variable. In addition, strains YJR27, YJR92, and YJR102, in certain harvests, increased pepper fruit numbers in field tests and red fruit weights in plastic house tests. Taken together, these results indicate that the screening procedure is rapid and reliable for the selection of potential biocontrol strains against P. capsici in pepper plants. In addition, these selected strains exhibited biocontrol activities against anthracnose, and some of the strains showed plant growth-promotion activities on pepper fruit.

  19. Biocontrol of Phytophthora Blight and Anthracnose in Pepper by Sequentially Selected Antagonistic Rhizobacteria against Phytophthora capsici

    Science.gov (United States)

    Sang, Mee Kyung; Shrestha, Anupama; Kim, Du-Yeon; Park, Kyungseok; Pak, Chun Ho; Kim, Ki Deok

    2013-01-01

    We previously developed a sequential screening procedure to select antagonistic bacterial strains against Phytophthora capsici in pepper plants. In this study, we used a modified screening procedure to select effective biocontrol strains against P. capsici; we evaluated the effect of selected strains on Phytophthora blight and anthracnose occurrence and fruit yield in pepper plants under field and plastic house conditions from 2007 to 2009. We selected four potential biocontrol strains (Pseudomonas otitidis YJR27, P. putida YJR92, Tsukamurella tyrosinosolvens YJR102, and Novosphingobium capsulatum YJR107) among 239 bacterial strains. In the 3-year field tests, all the selected strains significantly (P < 0.05) reduced Phytophthora blight without influencing rhizosphere microbial populations; they showed similar or better levels of disease suppressions than in metalaxyl treatment in the 2007 and 2009 tests, but not in the 2008 test. In the 2-year plastic house tests, all the selected strains significantly (P < 0.05) reduced anthracnose incidence in at least one of the test years, but their biocontrol activities were variable. In addition, strains YJR27, YJR92, and YJR102, in certain harvests, increased pepper fruit numbers in field tests and red fruit weights in plastic house tests. Taken together, these results indicate that the screening procedure is rapid and reliable for the selection of potential biocontrol strains against P. capsici in pepper plants. In addition, these selected strains exhibited biocontrol activities against anthracnose, and some of the strains showed plant growth-promotion activities on pepper fruit. PMID:25288942

  20. Population structure of the Chagas disease vector, Triatoma infestans, at the urban-rural interface.

    Science.gov (United States)

    Foley, Erica A; Khatchikian, Camilo E; Hwang, Josephine; Ancca-Juárez, Jenny; Borrini-Mayori, Katty; Quıspe-Machaca, Victor R; Levy, Michael Z; Brisson, Dustin

    2013-10-01

    The increasing rate of biological invasions resulting from human transport or human-mediated changes to the environment has had devastating ecological and public health consequences. The kissing bug, Triatoma infestans, has dispersed through the Peruvian city of Arequipa. The biological invasion of this insect has resulted in a public health crisis, putting thousands of residents of this city at risk of infection by Trypanosoma cruzi and subsequent development of Chagas disease. Here, we show that populations of Tria. infestans in geographically distinct districts within and around this urban centre share a common recent evolutionary history although current gene flow is restricted even between proximal sites. The population structure among the Tria. infestans in different districts is not correlated with the geographical distance between districts. These data suggest that migration among the districts is mediated by factors beyond the short-range migratory capabilities of Tria. infestans and that human movement has played a significant role in the structuring of the Tria. infestans population in the region. Rapid urbanization across southern South America will continue to create suitable environments for Tria. infestans, and knowledge of its urban dispersal patterns may play a fundamental role in mitigating human disease risk.

  1. Interacción entre poblaciones de Triatoma infestans y Triatoma sordida Interação entre população de Triatoma infestans e Triatoma sordida Population interactions between Triatoma infestans and Triatoma sordida

    Directory of Open Access Journals (Sweden)

    Maria Esther Bar

    1994-02-01

    Full Text Available Para conocer si se producía algún tipo de interacción entre poblaciones de Triatoma infestans y Triatoma sordida que convivían en una unidad experimental y explotaban el mismo recurso alimentario (ave se las estudió desde setiembre/1988 a abril/1989. La composición etaria inicial para cada especie fue: 27 N1, 7 N2, 11 N3, 3 N4, 8 N5, 4 machos y 10 hembras. La dinámica de población, el estado nutricional, la predación y la conducta gregaria, utilizados como parámetros de comparación, fueron estimados mediante censos mensuales. Triatoma infestans logró mayor éxito colonizador que T. sordida dado los valores alcanzados en: fecundidad (146 huevos/hembra, longevidad (157,8 días y mortalidad (39,4%, en comparación a los obtenidos por T. sordida: 118 huevos/hembra, 81,1 días y 54,0% respectivamente. La población de T. infestans tuvo un crecimiento de tipo exponencial, con una alta tasa de renovación ninfal, en contraposición, la población de T. sordida se extinguió tempranamente. En general, el peso promedio de los ejemplares de T. infestans se mantuvo en valores próximos al inicial, mientras que en T. sordida se redujo. Los grupos gregarios se conformaron mayoritariamente en el sector inferior de la pared 1 (próximo al hospedador, observándose mayor nivel de contagio en T. infestans. A partir de los resultados obtenidos se formula la hipótesis de la superioridad competitiva en T. infestans.Para saber se algum tipo de interação se produzia entre populações de Triatoma infestans e T. sordida que conviviam em uma unidade experimental e compartilharam o mesmo recurso alimentar (ave, foi realizado estudo que abrangeu o período de setembro de 1988 a abril de 1989. A composição etária inicial para cada espécie foi: 27 N1, 7 N2, 11 N3, 3 N4, 8 N5, 4 machos e 10 fêmeas. A dinâmica da população, o estado nutricional, a predação e a conduta gregria foram estimados mediante censos mensais. T. infestans obteve maior êxito

  2. Abscisic acid in salt stress predisposition to phytophthora root and crown rot in tomato and chrysanthemum.

    Science.gov (United States)

    Dileo, Matthew V; Pye, Matthew F; Roubtsova, Tatiana V; Duniway, John M; Macdonald, James D; Rizzo, David M; Bostock, Richard M

    2010-09-01

    Plants respond to changes in the environment with complex signaling networks, often under control of phytohormones that generate positive and negative crosstalk among downstream effectors of the response. Accordingly, brief dehydration stresses such as salinity and water deficit, which induce a rapid and transient systemic increase in levels of abscisic acid (ABA), can influence disease response pathways. ABA has been associated with susceptibility of plants to bacteria, fungi, and oomycetes but relatively little attention has been directed at its role in abiotic stress predisposition to root pathogens. This study examines the impact of brief salinity stress on infection of tomato and chrysanthemum roots by Phytophthora spp. Roots of plants in hydroponic culture exposed to a brief episode of salt (sodium chloride) stress prior to or after inoculation were severely diseased relative to nonstressed plants. Tomato roots remained in a predisposed state up to 24 h following removal from the stress. An increase in root ABA levels in tomato preceded or temporally paralleled the onset of stress-induced susceptibility, with levels declining in roots prior to recovery from the predisposed state. Exogenous ABA could substitute for salt stress and significantly enhanced pathogen colonization and disease development. ABA-deficient tomato mutants lacked the predisposition response, which could be restored by complementation of the mutant with exogenous ABA. In contrast, ethylene, which exacerbates disease symptoms in some host-parasite interactions, did not appear to contribute to the predisposition response. Thus, several lines of evidence support ABA as a critical and dominant factor in the salinity-induced predisposition to Phytophthora spp. infection.

  3. New role for Cdc14 phosphatase: localization to basal bodies in the oomycete phytophthora and its evolutionary coinheritance with eukaryotic flagella.

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    Audrey M V Ah-Fong

    Full Text Available Cdc14 protein phosphatases are well known for regulating the eukaryotic cell cycle, particularly during mitosis. Here we reveal a distinctly new role for Cdc14 based on studies of the microbial eukaryote Phytophthora infestans, the Irish potato famine agent. While Cdc14 is transcribed constitutively in yeast and animal cells, the P. infestans ortholog is expressed exclusively in spore stages of the life cycle and not in vegetative hyphae where the bulk of mitosis takes place. PiCdc14 expression is first detected in nuclei at sporulation, and during zoospore formation the protein accumulates at the basal body, which is the site from which flagella develop. The association of PiCdc14 with basal bodies was supported by co-localization studies with the DIP13 basal body protein and flagellar β-tubulin, and by demonstrating the enrichment of PiCdc14 in purified flagella-basal body complexes. Overexpressing PiCdc14 did not cause defects in growth or mitosis in hyphae, but interfered with cytoplasmic partitioning during zoosporogenesis. This cytokinetic defect might relate to its ability to bind microtubules, which was shown using an in vitro cosedimentation assay. The use of gene silencing to reveal the precise function of PiCdc14 in flagella is not possible since we showed previously that silencing prevents the formation of the precursor stage, sporangia. Nevertheless, the association of Cdc14 with flagella and basal bodies is consistent with their phylogenetic distribution in eukaryotes, as species that lack the ability to produce flagella generally also lack Cdc14. An ancestral role of Cdc14 in the flagellar stage of eukaryotes is thereby proposed.

  4. Oomycetes, effectors, and all that jazz.

    Science.gov (United States)

    Bozkurt, Tolga O; Schornack, Sebastian; Banfield, Mark J; Kamoun, Sophien

    2012-08-01

    Plant pathogenic oomycetes secrete a diverse repertoire of effector proteins that modulate host innate immunity and enable parasitic infection. Understanding how effectors evolve, translocate and traffic inside host cells, and perturb host processes are major themes in the study of oomycete-plant interactions. The last year has seen important progress in the study of oomycete effectors with, notably, the elucidation of the 3D structures of five RXLR effectors, and novel insights into how cytoplasmic effectors subvert host cells. In this review, we discuss these and other recent advances and highlight the most important open questions in oomycete effector biology. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. 78 FR 58993 - Notice of Request for Extension of Approval of an Information Collection; Phytophthora Ramorum...

    Science.gov (United States)

    2013-09-25

    ... Collection; Phytophthora Ramorum; Quarantine and Regulations AGENCY: Animal and Plant Health Inspection... Phytophthora ramorum. DATES: We will consider all comments that we receive on or before November 25, 2013... of regulated articles to prevent the spread of Phytophthora ramorum, contact Dr. Prakash K....

  6. 40 CFR 180.1057 - Phytophthora palmivora; exemption from requirement of tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Phytophthora palmivora; exemption from... From Tolerances § 180.1057 Phytophthora palmivora; exemption from requirement of tolerance. Phytophthora palmivora is exempted from the requirement of a tolerance in or on the raw agricultural...

  7. Risico voor resistente rassen, Phytophthora doorbreekt resisten tiegen (interview met Geert Kessel)

    NARCIS (Netherlands)

    Engwerda, J.; Kessel, G.J.T.

    2009-01-01

    In phytophthora-resistente aardappelrassen Bionica en Toluca kan alsnog phytoph-thora ontstaan. Wageningen UR waarschuwt telers hiervoor. Bij laboratoriumexperimenten zijn drie phytophthora-isolaten gevonden die het resistentiegen Blb2 hebben doorbroken. Het is voor het eerst dat de aardappelziekte

  8. An Oomycete CRN Effector Reprograms Expression of Plant HSP Genes by Targeting their Promoters.

    Directory of Open Access Journals (Sweden)

    Tianqiao Song

    2015-12-01

    Full Text Available Oomycete pathogens produce a large number of CRN effectors to manipulate plant immune responses and promote infection. However, their functional mechanisms are largely unknown. Here, we identified a Phytophthora sojae CRN effector PsCRN108 which contains a putative DNA-binding helix-hairpin-helix (HhH motif and acts in the plant cell nucleus. Silencing of the PsCRN108 gene reduced P. sojae virulence to soybean, while expression of the gene in Nicotiana benthamiana and Arabidopsis thaliana enhanced plant susceptibility to P. capsici. Moreover, PsCRN108 could inhibit expression of HSP genes in A. thaliana, N. benthamiana and soybean. Both the HhH motif and nuclear localization signal of this effector were required for its contribution to virulence and its suppression of HSP gene expression. Furthermore, we found that PsCRN108 targeted HSP promoters in an HSE- and HhH motif-dependent manner. PsCRN108 could inhibit the association of the HSE with the plant heat shock transcription factor AtHsfA1a, which initializes HSP gene expression in response to stress. Therefore, our data support a role for PsCRN108 as a nucleomodulin in down-regulating the expression of plant defense-related genes by directly targeting specific plant promoters.

  9. An Oomycete CRN Effector Reprograms Expression of Plant HSP Genes by Targeting their Promoters.

    Science.gov (United States)

    Song, Tianqiao; Ma, Zhenchuan; Shen, Danyu; Li, Qi; Li, Wanlin; Su, Liming; Ye, Tingyue; Zhang, Meixiang; Wang, Yuanchao; Dou, Daolong

    2015-12-01

    Oomycete pathogens produce a large number of CRN effectors to manipulate plant immune responses and promote infection. However, their functional mechanisms are largely unknown. Here, we identified a Phytophthora sojae CRN effector PsCRN108 which contains a putative DNA-binding helix-hairpin-helix (HhH) motif and acts in the plant cell nucleus. Silencing of the PsCRN108 gene reduced P. sojae virulence to soybean, while expression of the gene in Nicotiana benthamiana and Arabidopsis thaliana enhanced plant susceptibility to P. capsici. Moreover, PsCRN108 could inhibit expression of HSP genes in A. thaliana, N. benthamiana and soybean. Both the HhH motif and nuclear localization signal of this effector were required for its contribution to virulence and its suppression of HSP gene expression. Furthermore, we found that PsCRN108 targeted HSP promoters in an HSE- and HhH motif-dependent manner. PsCRN108 could inhibit the association of the HSE with the plant heat shock transcription factor AtHsfA1a, which initializes HSP gene expression in response to stress. Therefore, our data support a role for PsCRN108 as a nucleomodulin in down-regulating the expression of plant defense-related genes by directly targeting specific plant promoters.

  10. Behavioural Response of Triatoma infestans (Klug (Hemiptera: Reduviidae to Quinazolines

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    E. Zerba

    2005-09-01

    Full Text Available The behavioural responses of the haematophagous bug Triatoma infestans towards some previously identified components of its faeces: 4-methylquinazoline, 2,4- dimethylquinazoline and their mixtures were evaluated using a video tracking system. Fifth instar nymphs and females but not males were significantly attracted to polyethylene glycol formulations of 4-methyl + 2,4-dimethylquinazoline (50 μg each. Fifth instar nymphs were also attracted to 4-methylquinazoline alone (50 μg but females were only attracted by the mixture of both methyl quinazolines (50 μg each. Syntheses of both methyl quinazolines were carried out starting from 2-aminoacetophenone by modifying the conditions of reported procedures.

  11. Mapping the Progression of Phytophthora Ramorum

    Science.gov (United States)

    Banh, T.; Li, J.; El-Askary, H. M.

    2013-12-01

    There has been a plant pathogen, Phytophthora Ramorum that has been causing trouble for the plant species in the forests of California and Oregon. Phytophthora is essentially a water mold that infects oak species like California black oak, coast live oak as well as California bay laurel (Lamsal). What this project aims to accomplish is to observe any changes in NDVI values between the years of 2002 and 1994. What the project hopes to observe is a decline of NDVI values between the two years because the infection of Phytophtora Ramorum will cause stress to the plant or kill the plant, which will lower the values of NDVI. The project will utilizes satellite data to create NDVI images over the study area and two types of change detection methods to observe the differences between the NDVI values of the two years. Preliminary results for the project, data obtained from Landsat 7 ETM+ with a resolution of 240 meters, was not able to observe any significant changes. A finer resolution to differentiate the NDVI values would be needed. In addition the best way to keep the pathogen from getting out of control is with ground level management, or complete eradication of the pathogen. These eradication methods include burning the infected host plants and spreading herbicide (Alexander). With that in mind it would be ideal to have an early detection of the pathogen infestation. Therefore another goal of the project is to continue to research if remote sensing could play a role in an early detection method for the presence of Phytophtora Ramorum.

  12. Triatoma melanosoma, novo status para Triatoma infestans melanosoma Martinez, Olmedo & Carcavallo, 1987 (Hemiptera: Reduviidae Triatoma melanosoma, new status for Triatoma infestans melanosoma Martinez, Olmedo & Carcavallo, 1987 (Hemiptera: Reduviidae

    Directory of Open Access Journals (Sweden)

    Herman Lent

    1994-09-01

    Full Text Available Triatoma infestans melanosoma was described in 1987 by Martinez, Olmedo & Carcavallo. In the present work the authors make a redescription, adding new characters, and based on biological and morphological aspects raise up to the level of species and being identified as Triatoma melanosoma. A detailed morphological study of the external male genitalia was made.

  13. Population Structure of the Chagas Disease Vector Triatoma infestans in an Urban Environment

    Science.gov (United States)

    Khatchikian, Camilo E.; Foley, Erica A.; Barbu, Corentin M.; Hwang, Josephine; Ancca-Juárez, Jenny; Borrini-Mayori, Katty; Quıspe-Machaca, Victor R.; Naquira, Cesar; Brisson, Dustin; Levy, Michael Z.

    2015-01-01

    Chagas disease is a vector-borne disease endemic in Latin America. Triatoma infestans, a common vector of this disease, has recently expanded its range into rapidly developing cities of Latin America. We aim to identify the environmental features that affect the colonization and dispersal of T. infestans in an urban environment. We amplified 13 commonly used microsatellites from 180 T. infestans samples collected from a sampled transect in the city of Arequipa, Peru, in 2007 and 2011. We assessed the clustering of subpopulations and the effect of distance, sampling year, and city block location on genetic distance among pairs of insects. Despite evidence of genetic similarity, the majority of city blocks are characterized by one dominant insect genotype, suggesting the existence of barriers to dispersal. Our analyses show that streets represent an important barrier to the colonization and dispersion of T. infestans in Arequipa. The genetic data describe a T. infestans infestation history characterized by persistent local dispersal and occasional long-distance migration events that partially parallels the history of urban development. PMID:25646757

  14. Population structure of the Chagas disease vector Triatoma infestans in an urban environment.

    Science.gov (United States)

    Khatchikian, Camilo E; Foley, Erica A; Barbu, Corentin M; Hwang, Josephine; Ancca-Juárez, Jenny; Borrini-Mayori, Katty; Quıspe-Machaca, Victor R; Naquira, Cesar; Brisson, Dustin; Levy, Michael Z

    2015-02-01

    Chagas disease is a vector-borne disease endemic in Latin America. Triatoma infestans, a common vector of this disease, has recently expanded its range into rapidly developing cities of Latin America. We aim to identify the environmental features that affect the colonization and dispersal of T. infestans in an urban environment. We amplified 13 commonly used microsatellites from 180 T. infestans samples collected from a sampled transect in the city of Arequipa, Peru, in 2007 and 2011. We assessed the clustering of subpopulations and the effect of distance, sampling year, and city block location on genetic distance among pairs of insects. Despite evidence of genetic similarity, the majority of city blocks are characterized by one dominant insect genotype, suggesting the existence of barriers to dispersal. Our analyses show that streets represent an important barrier to the colonization and dispersion of T. infestans in Arequipa. The genetic data describe a T. infestans infestation history characterized by persistent local dispersal and occasional long-distance migration events that partially parallels the history of urban development.

  15. First Report of Widespread Wild Populations of Triatoma infestans (Reduviidae, Triatominae) in the Valleys of La Paz, Bolivia

    Science.gov (United States)

    Buitrago, Rosio; Waleckx, Etienne; Bosseno, Marie-France; Zoveda, Faustine; Vidaurre, Pablo; Salas, Renata; Mamani, Elio; Noireau, François; Brenière, Simone Frédérique

    2010-01-01

    Wild populations of Triatoma infestans, the main vector of Chagas disease in the Southern Cone countries, may be involved in reinfestation of human dwellings, limiting the success of vector-control campaigns in Bolivia. Knowledge of the distribution of these populations remains incomplete. We report here the detection of T. infestans wild populations in large areas in the department of La Paz, Bolivia. Among 18 sylvatic areas investigated, 17 were positive with T. infestans specimens. The infection rate of captured T. infestans with Trypanosoma cruzi was 85.7% in adult specimens. These results expand the geographical distribution of wild populations of T. infestans; it may be distributed throughout the Inter-Andean Dry Forest eco-region of Bolivia. The current information allows us to propose the hypothesis that a sylvatic origin of the reinfestation is located in the valleys of La Paz. PMID:20348501

  16. A molecular method to assess Phytophthora diversity in environmental samples.

    Science.gov (United States)

    Scibetta, Silvia; Schena, Leonardo; Chimento, Antonio; Cacciola, Santa O; Cooke, David E L

    2012-03-01

    Current molecular detection methods for the genus Phytophthora are specific to a few key species rather than the whole genus and this is a recognized weakness of protocols for ecological studies and international plant health legislation. In the present study a molecular approach was developed to detect Phytophthora species in soil and water samples using novel sets of genus-specific primers designed against the internal transcribed spacer (ITS) regions. Two different rDNA primer sets were tested: one assay amplified a long product including the ITS1, 5.8S and ITS2 regions (LP) and the other a shorter product including the ITS1 only (SP). Both assays specifically amplified products from Phytophthora species without cross-reaction with the related Pythium s. lato, however the SP assay proved the more sensitive and reliable. The method was validated using woodland soil and stream water from Invergowrie, Scotland. On-site use of a knapsack sprayer and in-line water filters proved more rapid and effective than centrifugation at sampling Phytophthora propagules. A total of 15 different Phytophthora phylotypes were identified which clustered within the reported ITS-clades 1, 2, 3, 6, 7 and 8. The range and type of the sequences detected varied from sample to sample and up to three and five different Phytophthora phylotypes were detected within a single sample of soil or water, respectively. The most frequently detected sequences were related to members of ITS-clade 6 (i.e. P. gonapodyides-like). The new method proved very effective at discriminating multiple species in a given sample and can also detect as yet unknown species. The reported primers and methods will prove valuable for ecological studies, biosecurity and commercial plant, soil or water (e.g. irrigation water) testing as well as the wider metagenomic sampling of this fascinating component of microbial pathogen diversity.

  17. Biocontrol of Phytophthora Blight and Anthracnose in Pepper by Sequentially Selected Antagonistic Rhizobacteria against Phytophthora capsici.

    Science.gov (United States)

    Sang, Mee Kyung; Shrestha, Anupama; Kim, Du-Yeon; Park, Kyungseok; Pak, Chun Ho; Kim, Ki Deok

    2013-06-01

    We previously developed a sequential screening procedure to select antagonistic bacterial strains against Phytophthora capsici in pepper plants. In this study, we used a modified screening procedure to select effective biocontrol strains against P. capsici; we evaluated the effect of selected strains on Phytophthora blight and anthracnose occurrence and fruit yield in pepper plants under field and plastic house conditions from 2007 to 2009. We selected four potential biocontrol strains (Pseudomonas otitidis YJR27, P. putida YJR92, Tsukamurella tyrosinosolvens YJR102, and Novosphingobium capsulatum YJR107) among 239 bacterial strains. In the 3-year field tests, all the selected strains significantly (P anthracnose incidence in at least one of the test years, but their biocontrol activities were variable. In addition, strains YJR27, YJR92, and YJR102, in certain harvests, increased pepper fruit numbers in field tests and red fruit weights in plastic house tests. Taken together, these results indicate that the screening procedure is rapid and reliable for the selection of potential biocontrol strains against P. capsici in pepper plants. In addition, these selected strains exhibited biocontrol activities against anthracnose, and some of the strains showed plant growth-promotion activities on pepper fruit.

  18. A two disulfide bridge Kazal domain from Phytophthora exhibits stable inhibitory activity against serine proteases of the subtilisin family

    Directory of Open Access Journals (Sweden)

    Kamoun Sophien

    2005-08-01

    Full Text Available Abstract Background Kazal-like serine protease inhibitors are defined by a conserved sequence motif. A typical Kazal domain contains six cysteine residues leading to three disulfide bonds with a 1–5/2–4/3–6 pattern. Most Kazal domains described so far belong to this class. However, a novel class of Kazal domains with two disulfide bridges resulting from the absence of the third and sixth cysteines have been found in biologically important molecules, such as human LEKTI, a 15-domain inhibitor associated with the severe congenital disease Netherton syndrome. These domains are referred to as atypical Kazal domains. Previously, EPI1, a Kazal-like protease inhibitor from the oomycete plant pathogen Phytophthora infestans, was shown to be a tight-binding inhibitor of subtilisin A. EPI1 also inhibits and interacts with the pathogenesis-related P69B subtilase of the host plant tomato, suggesting a role in virulence. EPI1 is composed of two Kazal domains, the four-cysteine atypical domain EPI1a and the typical domain EPI1b. Results In this study, we predicted the inhibition constants of EPI1a and EPI1b to subtilisin A using the additivity-based sequence to reactivity algorithm (Laskowski algorithm. The atypical domain EPI1a, but not the typical domain EPI1b, was predicted to have strong inhibitory activity against subtilisin A. Inhibition assays and coimmunoprecipitation experiments showed that recombinant domain EPI1a exhibited stable inhibitory activity against subilisin A and was solely responsible for inhibition and interaction with tomato P69B subtilase. Conclusion The finding that the two disulfide bridge atypical Kazal domain EPI1a is a stable inhibitor indicates that the missing two cysteines and their corresponding disulfide bond are not essential for inhibitor reactivity and stability. This report also suggests that the Laskowski algorithm originally developed and validated with typical Kazal domains might operate accurately for atypical

  19. Variations of the External Male Genitalia in Three Populations of Triatoma infestans Klug, 1834

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    Pires Herton Helder Rocha

    1998-01-01

    Full Text Available Triatoma infestans is the triatomine that presents the greatest dispersion area in South America. However, it is not known whether the original characteristics of this insect remained in its long dispersion process. The purpose of this work was to study comparatively the external male genitalia of insects from different populations of T. infestans, two from Brazil (Minas Gerais and Bahia and one from Bolivia (Cochabamba Valley, and to investigate the correlation between the morphological and behavioral variations. Differences were observed in one of the structures of the external genitalia (endosoma process that could be used to characterize the insects from the three populations studied.

  20. Deciphering interplay between Salmonella invasion effectors.

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    Robert J Cain

    2008-04-01

    Full Text Available Bacterial pathogens have evolved a specialized type III secretion system (T3SS to translocate virulence effector proteins directly into eukaryotic target cells. Salmonellae deploy effectors that trigger localized actin reorganization to force their own entry into non-phagocytic host cells. Six effectors (SipC, SipA, SopE/2, SopB, SptP can individually manipulate actin dynamics at the plasma membrane, which acts as a 'signaling hub' during Salmonella invasion. The extent of crosstalk between these spatially coincident effectors remains unknown. Here we describe trans and cisbinary entry effector interplay (BENEFIT screens that systematically examine functional associations between effectors following their delivery into the host cell. The results reveal extensive ordered synergistic and antagonistic relationships and their relative potency, and illuminate an unexpectedly sophisticated signaling network evolved through longstanding pathogen-host interaction.