Objective. To determine the expression of molecular markers of prostanoidufatty acid signalling i... more Objective. To determine the expression of molecular markers of prostanoidufatty acid signalling in leucocytes of patients with systemic sclerosis (SSc). Methods. Gene expression in patient leucocytes was analysed using real-time fluorescence reverse transcriptase polymerase chain reaction for tumour necrosis factor a (TNF-a), thromboxane synthase (TXAS, CYP5A), prostacyclin synthase (CYP8A), monocyte chemoattractant protein-1 (MCP-1), peroxisome proliferator-activated receptors (PPAR) a, d and c, low-density lipoprotein-associated lipoprotein lipase A 2 (LDL-PLA 2), apolipoprotein E (apoE) and cholesterol 27-hydroxylase (CYP27). Results. Both TNF-a and TXAS showed an increase in mean expression in the diseased group (6.3-fold and 5.6-fold respectively, P < 0.0001). These two markers, along with CYP27, PPARc and apoE, provided predictive markers for the development of carotid artery disease within the SSc patient population. Conclusion. The elevated levels of TNF-a and thromboxane seen in SSc patient sera are paralleled by increases in the expression of the appropriate genes in leucocytes. This method will allow us to screen for a large number of candidate markers of disease in order to increase our understanding of the processes underlying the pathology of SSc.
Suppression subtractive hybridisation was used to isolate 21 cDNAs ( bmi1- bmi21) up-regulated 1-... more Suppression subtractive hybridisation was used to isolate 21 cDNAs ( bmi1- bmi21) up-regulated 1-5 h post-inoculation (hpi) in a barley ( Hordeum vulgare L. cv. Pallas) near-isogenic line (NIL) P11 ( Mla13) challenged with either avirulent or virulent isolates of Blumeria graminis f. sp. hordei. Transcriptional changes at these time-points are crucial for the Mla-mediated hypersensitive response [W.R. Bushnell and Z. Liu (1994) Physiol Mol Plant Pathol 44:389-402]. Seven sequences were up-regulated by 1 hpi, when the pathogen has formed only the primary germ tube. Some transcripts were similar to genes with a role in regulating programmed cell death in animals, including NF kappaB and oxysterol-binding protein. Moreover, bmi7, similar to rice resistance gene Xa21, was rapidly up-regulated in both compatible and incompatible interactions, but was then down-regulated by 5 hpi in the virulent interaction. Only nine of the transcripts were up-regulated in mlo5 resistance in cv. Pallas NIL P22, confirming differential pathway induction between Mla13 and mlo5. However, eight sequences up-regulated in the Mla13 response in P11 were already highly elevated in uninoculated mlo5 mutant P22, suggesting that they may be negatively regulated by wild-type Mlo. Regulation of bmi sequences was investigated using salicylic acid, methyl jasmonate, ethylene, H(2)O(2), abscisic acid, wounding and a glucan elicitor. No single stimulus up-regulated all genes, suggesting either combinations of these stimuli, or additional stimuli, are involved in early Mla13 and mlo5 resistances. Whereas H(2)O(2) up- or down-regulated 17 of the transcripts detected in Northern analyses, salicylic acid stimulated only down-regulation of 5 transcripts.
... How to Cite. Cooke, DEL, Young, V., Birch, PRJ, Toth, R., Gourlay, F., Day, JP, Carnegie, SF ... more ... How to Cite. Cooke, DEL, Young, V., Birch, PRJ, Toth, R., Gourlay, F., Day, JP, Carnegie, SF and Duncan, JM (2003), Phenotypic and genotypic diversity of Phytophthora infestans populations in Scotland (1995–97). ... SEARCH BY CITATION. Volume: Issue: Page: ...
Phenylamide fungicides have been widely used for the control of oomycete-incited plant diseases f... more 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.
Oomycete plant pathogens cause a wide variety of economically and environmentally important plant... more 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 H2O. 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.
Phytophthora infestans causes late-blight, a devastating and re-emerging disease of potato crops.... more Phytophthora infestans causes late-blight, a devastating and re-emerging disease of potato crops. During the early stages of infection, P. infestans differentiates infection-specific structures such as appressoria for host epidermal cell penetration, followed by infection vesicles, and haustoria to establish a biotrophic phase of interaction. Here we report the cloning, from a suppression subtractive hybridization library, of a P. infestans gene called Pihmp1 encoding a putative glycosylated protein with four closely spaced transmembrane helices. Pihmp1 expression is upregulated in germinating cysts and in germinating cysts with appressoria, and significantly upregulated throughout infection of potato. Transient gene silencing of Pihmp1 led to loss of pathogenicity and indicated involvement of this gene in the penetration and early infection processes of P. infestans. P. infestans transformants expressing a Pihmp1::monomeric red fluorescent protein (mRFP) fusion demonstrated that Pihmp1 was translated in germinating sporangia, germinating cysts and appressoria, accumulated in the appressorium, and was located at the haustorial membrane during infection. Furthermore, we discovered that haustorial structures are formed over a 3 h period, maturing for up to 12 h, and that their formation is initiated only at sites on the surface of intercellular hyphae where Pihmp1::mRFP is localized. We propose that Pihmp1 is an integral membrane protein that provides physical stability to the plasma membrane of P. infestans infection structures. We have provided the first evidence that the surface of oomycete haustoria possess proteins specific to these biotrophic structures, and that formation of biotrophic structures (infection vesicles and haustoria) is essential to successful host colonization by P. infestans.
Unfortunately, the 9th author name was incorrectly published in the original publication. The com... more Unfortunately, the 9th author name was incorrectly published in the original publication. The complete correct name is given below. Chun-Peng Song The original article has been corrected.
Objective. To determine the expression of molecular markers of prostanoidufatty acid signalling i... more Objective. To determine the expression of molecular markers of prostanoidufatty acid signalling in leucocytes of patients with systemic sclerosis (SSc). Methods. Gene expression in patient leucocytes was analysed using real-time fluorescence reverse transcriptase polymerase chain reaction for tumour necrosis factor a (TNF-a), thromboxane synthase (TXAS, CYP5A), prostacyclin synthase (CYP8A), monocyte chemoattractant protein-1 (MCP-1), peroxisome proliferator-activated receptors (PPAR) a, d and c, low-density lipoprotein-associated lipoprotein lipase A 2 (LDL-PLA 2), apolipoprotein E (apoE) and cholesterol 27-hydroxylase (CYP27). Results. Both TNF-a and TXAS showed an increase in mean expression in the diseased group (6.3-fold and 5.6-fold respectively, P < 0.0001). These two markers, along with CYP27, PPARc and apoE, provided predictive markers for the development of carotid artery disease within the SSc patient population. Conclusion. The elevated levels of TNF-a and thromboxane seen in SSc patient sera are paralleled by increases in the expression of the appropriate genes in leucocytes. This method will allow us to screen for a large number of candidate markers of disease in order to increase our understanding of the processes underlying the pathology of SSc.
Suppression subtractive hybridisation was used to isolate 21 cDNAs ( bmi1- bmi21) up-regulated 1-... more Suppression subtractive hybridisation was used to isolate 21 cDNAs ( bmi1- bmi21) up-regulated 1-5 h post-inoculation (hpi) in a barley ( Hordeum vulgare L. cv. Pallas) near-isogenic line (NIL) P11 ( Mla13) challenged with either avirulent or virulent isolates of Blumeria graminis f. sp. hordei. Transcriptional changes at these time-points are crucial for the Mla-mediated hypersensitive response [W.R. Bushnell and Z. Liu (1994) Physiol Mol Plant Pathol 44:389-402]. Seven sequences were up-regulated by 1 hpi, when the pathogen has formed only the primary germ tube. Some transcripts were similar to genes with a role in regulating programmed cell death in animals, including NF kappaB and oxysterol-binding protein. Moreover, bmi7, similar to rice resistance gene Xa21, was rapidly up-regulated in both compatible and incompatible interactions, but was then down-regulated by 5 hpi in the virulent interaction. Only nine of the transcripts were up-regulated in mlo5 resistance in cv. Pallas NIL P22, confirming differential pathway induction between Mla13 and mlo5. However, eight sequences up-regulated in the Mla13 response in P11 were already highly elevated in uninoculated mlo5 mutant P22, suggesting that they may be negatively regulated by wild-type Mlo. Regulation of bmi sequences was investigated using salicylic acid, methyl jasmonate, ethylene, H(2)O(2), abscisic acid, wounding and a glucan elicitor. No single stimulus up-regulated all genes, suggesting either combinations of these stimuli, or additional stimuli, are involved in early Mla13 and mlo5 resistances. Whereas H(2)O(2) up- or down-regulated 17 of the transcripts detected in Northern analyses, salicylic acid stimulated only down-regulation of 5 transcripts.
... How to Cite. Cooke, DEL, Young, V., Birch, PRJ, Toth, R., Gourlay, F., Day, JP, Carnegie, SF ... more ... How to Cite. Cooke, DEL, Young, V., Birch, PRJ, Toth, R., Gourlay, F., Day, JP, Carnegie, SF and Duncan, JM (2003), Phenotypic and genotypic diversity of Phytophthora infestans populations in Scotland (1995–97). ... SEARCH BY CITATION. Volume: Issue: Page: ...
Phenylamide fungicides have been widely used for the control of oomycete-incited plant diseases f... more 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.
Oomycete plant pathogens cause a wide variety of economically and environmentally important plant... more 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 H2O. 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.
Phytophthora infestans causes late-blight, a devastating and re-emerging disease of potato crops.... more Phytophthora infestans causes late-blight, a devastating and re-emerging disease of potato crops. During the early stages of infection, P. infestans differentiates infection-specific structures such as appressoria for host epidermal cell penetration, followed by infection vesicles, and haustoria to establish a biotrophic phase of interaction. Here we report the cloning, from a suppression subtractive hybridization library, of a P. infestans gene called Pihmp1 encoding a putative glycosylated protein with four closely spaced transmembrane helices. Pihmp1 expression is upregulated in germinating cysts and in germinating cysts with appressoria, and significantly upregulated throughout infection of potato. Transient gene silencing of Pihmp1 led to loss of pathogenicity and indicated involvement of this gene in the penetration and early infection processes of P. infestans. P. infestans transformants expressing a Pihmp1::monomeric red fluorescent protein (mRFP) fusion demonstrated that Pihmp1 was translated in germinating sporangia, germinating cysts and appressoria, accumulated in the appressorium, and was located at the haustorial membrane during infection. Furthermore, we discovered that haustorial structures are formed over a 3 h period, maturing for up to 12 h, and that their formation is initiated only at sites on the surface of intercellular hyphae where Pihmp1::mRFP is localized. We propose that Pihmp1 is an integral membrane protein that provides physical stability to the plasma membrane of P. infestans infection structures. We have provided the first evidence that the surface of oomycete haustoria possess proteins specific to these biotrophic structures, and that formation of biotrophic structures (infection vesicles and haustoria) is essential to successful host colonization by P. infestans.
Unfortunately, the 9th author name was incorrectly published in the original publication. The com... more Unfortunately, the 9th author name was incorrectly published in the original publication. The complete correct name is given below. Chun-Peng Song The original article has been corrected.
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