The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Qiang Sheng - One of the best experts on this subject based on the ideXlab platform.
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enzyme assay of curvularia eragrostidis strain qz 2000 on Digitaria sanguinalis
Journal of Henan Agricultural Sciences, 2010Co-Authors: Wang Jianshu, Zhu Yunzhi, Liu Guiqiao, Qiang ShengAbstract:It was measured that enzyme assay in conidia of Curvularia eragrostidis strain QZ-2000 storaged for different time and in Digitaria sanguinalis infected by conidial suspension of Curvularia eragrostidis,low dosage chemical herbicide and combination.The esterase isozymes showed different activities and mobility by polyacrylamide gel electrophoresis in Digitaria sanguinalis treated and in conidia of Curvularia eragrostidis strain QZ-2000.
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synergy of the mixture of curvularia eragrostidis strain qz 2000 and low rate herbicide to Digitaria sanguinalis indicated by some physiological parameters
Journal of Henan Agricultural Sciences, 2010Co-Authors: Wang Jianshu, Zhu Yunzhi, Qiang ShengAbstract:Curvularia eragrostidis strain QZ-2000 has a potential for biological control of large crabgrass(Digitaria sanguinalis).Its control efficacy,which is affected by environmental humidity conditions,can be improved and the dependence on the environment can be reduced through application of the mixture of Curvularia eragrostidis strain QZ-2000 conidia and low-rate herbicide.It is difficult to assess conidia or herbicide playing a main role in synergy only based on injured morphological symptoms of large crabgrass.The chlorophyll,soluble protein and MDA content in treated large crabgrass leaves were tested to enunciate the change of those physiological parameters and analyze the synergistic mechanism.The results showed chlorophyll and soluble protein content decreased and MDA content increased in all treatments.The mixture of conidia and low-rate herbicide demonstrated the most significant decrease of chlorophyll and soluble protein content while the most significant increase of MDA content.This indicated that there was synergy between conidia and low-rate herbicide,in which conidia played the predominant role.
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the effect of the mycotoxin of α β dehydrocurvularin from curvularia eragrostidis on ps ii in Digitaria sanguinalis
Scientia Agricultura Sinica, 2005Co-Authors: Jiang Shujun, Qiang ShengAbstract:Curvularia eragrostidis strain QZ2000, a potential biocontrol candidate for large crabgrass [Digitaria sanguinalis (L.) Scop], produced a mycotoxin with herbicidal activity, which was identified as α,β-dehydrocurvularin. Inhibition of photosynthetic electron transport in isolated thylakoids from large crabgrass was investigated. The electron transport activities of the photosystem II (PS II) in isolated thylakoids was significantly inhibited by the mycotoxin. At a concentration of 0.688 mmol·L-1, the electron transport rate of PS II was reduced by 19.37%. The mycotoxin had a little effect on the electron transport rate of the photosystemⅠ (PSⅠ). When the detached leaves were treated with mycotoxin (0.516 mmol·L-1) for 24 h, Fv/Fo, Fv/Fm, ΦPSⅡ, qP, qN, Fm values of large crabgrass declined significantly, but Fo values increased considerably. In the experiment, the changes of chlorophyll fluorescence parameter suggested that the mycotoxin was similar as herbicides atrazine, simazine, and diuron with inhibitory activities on the PS II, namely, the mycotoxin may damage the PS II reaction center and blocks the reoxidation of the primary electron acceptor (QA). These results indicate that the mode of action of mycotoxin might be the damage of PS II reaction center and inhibition of the reoxidation of the primary electron acceptor (QA), which resulted in the inhibition in electron transport between PS II reaction center and QA or between QA and the second electron acceptor (QB). Sequentially photophosphorylation and carbon assimilation were inhibited and metabolism of large crabgrass was disturbed. The decrease of qN value suggested that mycotoxin caused the accumulation of reductive electron acceptor and increased the production of the free radicals. This could be the cause of the damage of PS II reaction center.
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isolation and pathogenicity of indigenous fungi to Digitaria sanguinalis
Journal of Biological Control, 2004Co-Authors: Qiang ShengAbstract:Six pathogenic fungi were isolated from naturally infected plant of Digitaria sanguinalis. They were identified as Curvularia intermedia, C. lunata, Helminthosporium nodulosum, Piricularia grisea, Altarnaria alternata and Fusarium roseum. Among them, C. lunata and H. nodulosum infected corn and P. grisea infected rice slightly. Under the condition of 48h dew period, A. alternata and F. roseum did not cause death of D. sanguinalis seedlings at the 1-3 leaf stage, but C. intermedia provided good control (90%-100% in greenhouse and 75% in field) of the weed at the 1-3.5 leaf stage. Initial host range test were done with C. intermedia. The pathogen did not infect rice, corn, soybean, cotton, wheat, sunflower, peanut, and lawn. C. intermedia may be a potential agent as bioherbicide to control crabgrass.
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influence of some factors on pathogenicity of strain qz 2000 to Digitaria sanguinalis
Journal of Nanjing Agricultural University, 2004Co-Authors: Qiang ShengAbstract:The effect of dew duration,inoculum potential,host-plant growth stage,temperature,photoperiod in dew duration,spray volume and media on the pathogenicity of strain QZ-2000 to crabgrass(Digitaria sanguinalis)was studied.It was showed that strain QZ-2000 could cause severe disease on crabgrass seedlings from 1 to 4 leaf stage.For the disease development,the optimal temperature after the inoculation of strain QZ-2000 was 1530 ℃.The pathogenicity of the strain was enhanced with the increase of spore concentration and dew duration.A spore concentration of 10 6 mL -1 caused 100% mortality of the first to third leaf stage plants after being experienced for a 24 h dew duration.The need for a long dew duration(at least 24 h)for infection and disease development could be decreased by adding oil emulsion.Spray volume significantly affected the pathogenic efficiency.It was indicated that the strain QZ-2000 could be used as potential mycoherbicide under specific environmental conditions against crabgrass.
Jean Vidal - One of the best experts on this subject based on the ideXlab platform.
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in situ c4 phosphoenolpyruvate carboxylase activity and kinetic properties in isolated Digitaria sanguinalis mesophyll cells
Photosynthesis Research, 2004Co-Authors: Jeannoel Pierre, Joseluis Prieto, Pierre Gadal, Jean VidalAbstract:Isolated mesophyll cells from darkened leaves of the C4 plant Digitaria sanguinalis keep functional plasmodesmata that allow the free exchange of low molecular mass compounds with the surrounding medium. This cell suspension system has been used to measure C4 PEPC activity in situ using a spectrophotometric assay. Compared to the extracted enzyme assayed in vitro, the essentially non-phosphorylated ‘in-cell’ C4 PEPC showed altered functional and regulatory properties. While the S0.5 for PEP at pH 7.3 was only modestly changed (0.4–0.6 mM), the response to pH was shifted towards the acidic range, being close to the maximal value at pH 7.3. Using expected physiological concentrations of the metabolites, at pH 7.3, the IC50 for malate showed a five-fold increase, from 1.5 to 8 mM, and was increased further to 22 mM in the presence of the allosteric activator glucose-6-phosphate (4 mM). Thiol compounds like DTT, mercaptoethanol and reduced glutathione weakened the in-situ sensitivity of C4 PEPC to malate. However, none of them had any effect on this process in vitro. This was not due to thioredoxin-mediated or phoshorylation-dependent processes. Since glutathione is a physiological compound that is present mostly in the reduced state in the cell cytosol, a possible contribution of this thiol to the protection of the enzyme against malate in situ is proposed.
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a ca2 dependent protein kinase with characteristics of protein kinase c in leaves and mesophyll cell protoplasts from Digitaria sanguinalis possible involvement in the c4 phosphoenolpyruvate carboxylase phosphorylation cascade
Biochemical and Biophysical Research Communications, 2004Co-Authors: Lidia Osuna, Sylvie Coursol, Jeannoel Pierre, Jean VidalAbstract:Abstract In mesophyll cells (MC) of Digitaria sanguinalis, the C4-phosphoenolpyruvate carboxylase (C4-PEPC) initiating the photosynthetic pathway is controlled by a complex light-dependent phosphorylation process. We showed previously that the transduction cascade involves the phosphoinositide pathway and a Ca2+-dependent step, which precedes the upregulation of the PEPC kinase (PEPCk). We have now further characterized the cascade component requiring Ca2+. A Ca2+-dependent protein kinase that shows several characteristics of the conventional type of mammalian protein kinase C (PKC) was detected in protein extracts from mesophyll cell protoplasts (MCPs). It catalyzed the in vitro phosphorylation of the C1-peptide PKC substrate and was markedly inhibited by a PKC-specific pseudosubstrate domain. However, it was only modestly activated by the phospholipids phosphatidylserine and lysophosphatidylcholine, while choline, oleyl acetylglycerol, phosphatidylinositol, and the phorbol ester phorbol 12-myristate 13-acetate did not show any effect. Nevertheless, its activity was found to be associated with a polypeptide of 75 kDa that was recognized by a PKC antibody raised against the C-terminus of rabbit PKCβ II. In addition, this protein kinase was also inhibited by the Ca2+-dependent protein kinase (CDPK)/PKC inhibitors W7, H7, and staurosporine. Surprisingly, it was found to be phosphorylated in dark-adapted MCPs, albeit to a low extent, and this did not change during protoplast induction by light. W7, H7, and staurosporine were shown to markedly inhibit C4-PEPC phosphorylation in light-treated MCPs. These results support the view that this protein kinase is a good candidate to represent the Ca2+-activated component of the C4-PEPC phosphorylation cascade.
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cloning and characterization of a phospholipase c from the c4 plant Digitaria sanguinalis
Journal of Experimental Botany, 2002Co-Authors: Sylvie Coursol, Jeannoel Pierre, Jean Vidal, Jeanine GrisvardAbstract:As a PLC activity was implicated in the light transduction pathway that controls C4 photosynthesis in Digitaria sanguinalis, a full length PLC cDNA (DsPLC2) was cloned. The proteins encoded by the two possible open reading frames were produced in Escherichia coli; they both harbour a PLC activity but with different response to Ca 2q concentration, and with different sensitivity to the PLC inhibitor U-73122.
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an increase in phosphoinositide specific phospholipase c activity precedes induction of c4 phosphoenolpyruvate carboxylase phosphorylation in illuminated and nh4cl treated protoplasts from Digitaria sanguinalis
Plant Journal, 2000Co-Authors: Sylvie Coursol, Jean Vidal, Nathalie Giglioliguivarch, Jeannoel PierreAbstract:A Ca 2+ -dependent phosphoinositide-specific phospholipase C (PI-PLC) activity has been characterized in the microsomal fraction of Digitaria sanguinalis mesophyll cell protoplasts. Microsomal PI-PLC was found to be inhibited in vitro by a mammalian anti-PLC-δ1 antibody and by the aminosteroide U-73122, an inhibitor of PI-PLC activity in animal cells. In Western blot experiments, the antibody recognized an 85kDa protein in both microsomal protein extracts from mesophyll protoplasts and rat brain protein extracts containing the authentic enzyme. The involvement of the microsomal PI-PLC in the light-dependent transduction pathway leading to the phosphorylation of C4 phosphoenolpyruvate carboxylase (PEPC) was investigated in D. sanguinalis protoplasts. A transient increase in the PI-PLC reaction product inositol-1,4,5-trisphosphate (Ins(1,4,5)P 3 ) was observed in situ during early induction of the C4 PEPC phosphorylation cascade. U-73122, but not the inactive analogue U-73343, efficiently blocked the transient accumulation of Ins(1,4,5)P3, and both the increase in C4 PEPC kinase activity and C4 PEPC phosphorylation in illuminated and weak base-treated protoplasts. Taken together, these data suggest that PI-PLC-based signalling is a committed step in the cascade controlling the regulation of C4 PEPC phosphorylation in C4 leaves.
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An increase in phosphoinositide‐specific phospholipase C activity precedes induction of C4 phosphoenolpyruvate carboxylase phosphorylation in illuminated and NH4Cl‐treated protoplasts from Digitaria sanguinalis
Plant Journal, 2000Co-Authors: Sylvie Coursol, Jean Vidal, Nathalie Giglioli-guivarc’h, Jeannoel PierreAbstract:A Ca 2+ -dependent phosphoinositide-specific phospholipase C (PI-PLC) activity has been characterized in the microsomal fraction of Digitaria sanguinalis mesophyll cell protoplasts. Microsomal PI-PLC was found to be inhibited in vitro by a mammalian anti-PLC-δ1 antibody and by the aminosteroide U-73122, an inhibitor of PI-PLC activity in animal cells. In Western blot experiments, the antibody recognized an 85kDa protein in both microsomal protein extracts from mesophyll protoplasts and rat brain protein extracts containing the authentic enzyme. The involvement of the microsomal PI-PLC in the light-dependent transduction pathway leading to the phosphorylation of C4 phosphoenolpyruvate carboxylase (PEPC) was investigated in D. sanguinalis protoplasts. A transient increase in the PI-PLC reaction product inositol-1,4,5-trisphosphate (Ins(1,4,5)P 3 ) was observed in situ during early induction of the C4 PEPC phosphorylation cascade. U-73122, but not the inactive analogue U-73343, efficiently blocked the transient accumulation of Ins(1,4,5)P3, and both the increase in C4 PEPC kinase activity and C4 PEPC phosphorylation in illuminated and weak base-treated protoplasts. Taken together, these data suggest that PI-PLC-based signalling is a committed step in the cascade controlling the regulation of C4 PEPC phosphorylation in C4 leaves.
Jeannoel Pierre - One of the best experts on this subject based on the ideXlab platform.
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in situ c4 phosphoenolpyruvate carboxylase activity and kinetic properties in isolated Digitaria sanguinalis mesophyll cells
Photosynthesis Research, 2004Co-Authors: Jeannoel Pierre, Joseluis Prieto, Pierre Gadal, Jean VidalAbstract:Isolated mesophyll cells from darkened leaves of the C4 plant Digitaria sanguinalis keep functional plasmodesmata that allow the free exchange of low molecular mass compounds with the surrounding medium. This cell suspension system has been used to measure C4 PEPC activity in situ using a spectrophotometric assay. Compared to the extracted enzyme assayed in vitro, the essentially non-phosphorylated ‘in-cell’ C4 PEPC showed altered functional and regulatory properties. While the S0.5 for PEP at pH 7.3 was only modestly changed (0.4–0.6 mM), the response to pH was shifted towards the acidic range, being close to the maximal value at pH 7.3. Using expected physiological concentrations of the metabolites, at pH 7.3, the IC50 for malate showed a five-fold increase, from 1.5 to 8 mM, and was increased further to 22 mM in the presence of the allosteric activator glucose-6-phosphate (4 mM). Thiol compounds like DTT, mercaptoethanol and reduced glutathione weakened the in-situ sensitivity of C4 PEPC to malate. However, none of them had any effect on this process in vitro. This was not due to thioredoxin-mediated or phoshorylation-dependent processes. Since glutathione is a physiological compound that is present mostly in the reduced state in the cell cytosol, a possible contribution of this thiol to the protection of the enzyme against malate in situ is proposed.
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a ca2 dependent protein kinase with characteristics of protein kinase c in leaves and mesophyll cell protoplasts from Digitaria sanguinalis possible involvement in the c4 phosphoenolpyruvate carboxylase phosphorylation cascade
Biochemical and Biophysical Research Communications, 2004Co-Authors: Lidia Osuna, Sylvie Coursol, Jeannoel Pierre, Jean VidalAbstract:Abstract In mesophyll cells (MC) of Digitaria sanguinalis, the C4-phosphoenolpyruvate carboxylase (C4-PEPC) initiating the photosynthetic pathway is controlled by a complex light-dependent phosphorylation process. We showed previously that the transduction cascade involves the phosphoinositide pathway and a Ca2+-dependent step, which precedes the upregulation of the PEPC kinase (PEPCk). We have now further characterized the cascade component requiring Ca2+. A Ca2+-dependent protein kinase that shows several characteristics of the conventional type of mammalian protein kinase C (PKC) was detected in protein extracts from mesophyll cell protoplasts (MCPs). It catalyzed the in vitro phosphorylation of the C1-peptide PKC substrate and was markedly inhibited by a PKC-specific pseudosubstrate domain. However, it was only modestly activated by the phospholipids phosphatidylserine and lysophosphatidylcholine, while choline, oleyl acetylglycerol, phosphatidylinositol, and the phorbol ester phorbol 12-myristate 13-acetate did not show any effect. Nevertheless, its activity was found to be associated with a polypeptide of 75 kDa that was recognized by a PKC antibody raised against the C-terminus of rabbit PKCβ II. In addition, this protein kinase was also inhibited by the Ca2+-dependent protein kinase (CDPK)/PKC inhibitors W7, H7, and staurosporine. Surprisingly, it was found to be phosphorylated in dark-adapted MCPs, albeit to a low extent, and this did not change during protoplast induction by light. W7, H7, and staurosporine were shown to markedly inhibit C4-PEPC phosphorylation in light-treated MCPs. These results support the view that this protein kinase is a good candidate to represent the Ca2+-activated component of the C4-PEPC phosphorylation cascade.
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cloning and characterization of a phospholipase c from the c4 plant Digitaria sanguinalis
Journal of Experimental Botany, 2002Co-Authors: Sylvie Coursol, Jeannoel Pierre, Jean Vidal, Jeanine GrisvardAbstract:As a PLC activity was implicated in the light transduction pathway that controls C4 photosynthesis in Digitaria sanguinalis, a full length PLC cDNA (DsPLC2) was cloned. The proteins encoded by the two possible open reading frames were produced in Escherichia coli; they both harbour a PLC activity but with different response to Ca 2q concentration, and with different sensitivity to the PLC inhibitor U-73122.
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an increase in phosphoinositide specific phospholipase c activity precedes induction of c4 phosphoenolpyruvate carboxylase phosphorylation in illuminated and nh4cl treated protoplasts from Digitaria sanguinalis
Plant Journal, 2000Co-Authors: Sylvie Coursol, Jean Vidal, Nathalie Giglioliguivarch, Jeannoel PierreAbstract:A Ca 2+ -dependent phosphoinositide-specific phospholipase C (PI-PLC) activity has been characterized in the microsomal fraction of Digitaria sanguinalis mesophyll cell protoplasts. Microsomal PI-PLC was found to be inhibited in vitro by a mammalian anti-PLC-δ1 antibody and by the aminosteroide U-73122, an inhibitor of PI-PLC activity in animal cells. In Western blot experiments, the antibody recognized an 85kDa protein in both microsomal protein extracts from mesophyll protoplasts and rat brain protein extracts containing the authentic enzyme. The involvement of the microsomal PI-PLC in the light-dependent transduction pathway leading to the phosphorylation of C4 phosphoenolpyruvate carboxylase (PEPC) was investigated in D. sanguinalis protoplasts. A transient increase in the PI-PLC reaction product inositol-1,4,5-trisphosphate (Ins(1,4,5)P 3 ) was observed in situ during early induction of the C4 PEPC phosphorylation cascade. U-73122, but not the inactive analogue U-73343, efficiently blocked the transient accumulation of Ins(1,4,5)P3, and both the increase in C4 PEPC kinase activity and C4 PEPC phosphorylation in illuminated and weak base-treated protoplasts. Taken together, these data suggest that PI-PLC-based signalling is a committed step in the cascade controlling the regulation of C4 PEPC phosphorylation in C4 leaves.
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An increase in phosphoinositide‐specific phospholipase C activity precedes induction of C4 phosphoenolpyruvate carboxylase phosphorylation in illuminated and NH4Cl‐treated protoplasts from Digitaria sanguinalis
Plant Journal, 2000Co-Authors: Sylvie Coursol, Jean Vidal, Nathalie Giglioli-guivarc’h, Jeannoel PierreAbstract:A Ca 2+ -dependent phosphoinositide-specific phospholipase C (PI-PLC) activity has been characterized in the microsomal fraction of Digitaria sanguinalis mesophyll cell protoplasts. Microsomal PI-PLC was found to be inhibited in vitro by a mammalian anti-PLC-δ1 antibody and by the aminosteroide U-73122, an inhibitor of PI-PLC activity in animal cells. In Western blot experiments, the antibody recognized an 85kDa protein in both microsomal protein extracts from mesophyll protoplasts and rat brain protein extracts containing the authentic enzyme. The involvement of the microsomal PI-PLC in the light-dependent transduction pathway leading to the phosphorylation of C4 phosphoenolpyruvate carboxylase (PEPC) was investigated in D. sanguinalis protoplasts. A transient increase in the PI-PLC reaction product inositol-1,4,5-trisphosphate (Ins(1,4,5)P 3 ) was observed in situ during early induction of the C4 PEPC phosphorylation cascade. U-73122, but not the inactive analogue U-73343, efficiently blocked the transient accumulation of Ins(1,4,5)P3, and both the increase in C4 PEPC kinase activity and C4 PEPC phosphorylation in illuminated and weak base-treated protoplasts. Taken together, these data suggest that PI-PLC-based signalling is a committed step in the cascade controlling the regulation of C4 PEPC phosphorylation in C4 leaves.
Wang Jianshu - One of the best experts on this subject based on the ideXlab platform.
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enzyme assay of curvularia eragrostidis strain qz 2000 on Digitaria sanguinalis
Journal of Henan Agricultural Sciences, 2010Co-Authors: Wang Jianshu, Zhu Yunzhi, Liu Guiqiao, Qiang ShengAbstract:It was measured that enzyme assay in conidia of Curvularia eragrostidis strain QZ-2000 storaged for different time and in Digitaria sanguinalis infected by conidial suspension of Curvularia eragrostidis,low dosage chemical herbicide and combination.The esterase isozymes showed different activities and mobility by polyacrylamide gel electrophoresis in Digitaria sanguinalis treated and in conidia of Curvularia eragrostidis strain QZ-2000.
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synergy of the mixture of curvularia eragrostidis strain qz 2000 and low rate herbicide to Digitaria sanguinalis indicated by some physiological parameters
Journal of Henan Agricultural Sciences, 2010Co-Authors: Wang Jianshu, Zhu Yunzhi, Qiang ShengAbstract:Curvularia eragrostidis strain QZ-2000 has a potential for biological control of large crabgrass(Digitaria sanguinalis).Its control efficacy,which is affected by environmental humidity conditions,can be improved and the dependence on the environment can be reduced through application of the mixture of Curvularia eragrostidis strain QZ-2000 conidia and low-rate herbicide.It is difficult to assess conidia or herbicide playing a main role in synergy only based on injured morphological symptoms of large crabgrass.The chlorophyll,soluble protein and MDA content in treated large crabgrass leaves were tested to enunciate the change of those physiological parameters and analyze the synergistic mechanism.The results showed chlorophyll and soluble protein content decreased and MDA content increased in all treatments.The mixture of conidia and low-rate herbicide demonstrated the most significant decrease of chlorophyll and soluble protein content while the most significant increase of MDA content.This indicated that there was synergy between conidia and low-rate herbicide,in which conidia played the predominant role.
Sylvie Coursol - One of the best experts on this subject based on the ideXlab platform.
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a ca2 dependent protein kinase with characteristics of protein kinase c in leaves and mesophyll cell protoplasts from Digitaria sanguinalis possible involvement in the c4 phosphoenolpyruvate carboxylase phosphorylation cascade
Biochemical and Biophysical Research Communications, 2004Co-Authors: Lidia Osuna, Sylvie Coursol, Jeannoel Pierre, Jean VidalAbstract:Abstract In mesophyll cells (MC) of Digitaria sanguinalis, the C4-phosphoenolpyruvate carboxylase (C4-PEPC) initiating the photosynthetic pathway is controlled by a complex light-dependent phosphorylation process. We showed previously that the transduction cascade involves the phosphoinositide pathway and a Ca2+-dependent step, which precedes the upregulation of the PEPC kinase (PEPCk). We have now further characterized the cascade component requiring Ca2+. A Ca2+-dependent protein kinase that shows several characteristics of the conventional type of mammalian protein kinase C (PKC) was detected in protein extracts from mesophyll cell protoplasts (MCPs). It catalyzed the in vitro phosphorylation of the C1-peptide PKC substrate and was markedly inhibited by a PKC-specific pseudosubstrate domain. However, it was only modestly activated by the phospholipids phosphatidylserine and lysophosphatidylcholine, while choline, oleyl acetylglycerol, phosphatidylinositol, and the phorbol ester phorbol 12-myristate 13-acetate did not show any effect. Nevertheless, its activity was found to be associated with a polypeptide of 75 kDa that was recognized by a PKC antibody raised against the C-terminus of rabbit PKCβ II. In addition, this protein kinase was also inhibited by the Ca2+-dependent protein kinase (CDPK)/PKC inhibitors W7, H7, and staurosporine. Surprisingly, it was found to be phosphorylated in dark-adapted MCPs, albeit to a low extent, and this did not change during protoplast induction by light. W7, H7, and staurosporine were shown to markedly inhibit C4-PEPC phosphorylation in light-treated MCPs. These results support the view that this protein kinase is a good candidate to represent the Ca2+-activated component of the C4-PEPC phosphorylation cascade.
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cloning and characterization of a phospholipase c from the c4 plant Digitaria sanguinalis
Journal of Experimental Botany, 2002Co-Authors: Sylvie Coursol, Jeannoel Pierre, Jean Vidal, Jeanine GrisvardAbstract:As a PLC activity was implicated in the light transduction pathway that controls C4 photosynthesis in Digitaria sanguinalis, a full length PLC cDNA (DsPLC2) was cloned. The proteins encoded by the two possible open reading frames were produced in Escherichia coli; they both harbour a PLC activity but with different response to Ca 2q concentration, and with different sensitivity to the PLC inhibitor U-73122.
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an increase in phosphoinositide specific phospholipase c activity precedes induction of c4 phosphoenolpyruvate carboxylase phosphorylation in illuminated and nh4cl treated protoplasts from Digitaria sanguinalis
Plant Journal, 2000Co-Authors: Sylvie Coursol, Jean Vidal, Nathalie Giglioliguivarch, Jeannoel PierreAbstract:A Ca 2+ -dependent phosphoinositide-specific phospholipase C (PI-PLC) activity has been characterized in the microsomal fraction of Digitaria sanguinalis mesophyll cell protoplasts. Microsomal PI-PLC was found to be inhibited in vitro by a mammalian anti-PLC-δ1 antibody and by the aminosteroide U-73122, an inhibitor of PI-PLC activity in animal cells. In Western blot experiments, the antibody recognized an 85kDa protein in both microsomal protein extracts from mesophyll protoplasts and rat brain protein extracts containing the authentic enzyme. The involvement of the microsomal PI-PLC in the light-dependent transduction pathway leading to the phosphorylation of C4 phosphoenolpyruvate carboxylase (PEPC) was investigated in D. sanguinalis protoplasts. A transient increase in the PI-PLC reaction product inositol-1,4,5-trisphosphate (Ins(1,4,5)P 3 ) was observed in situ during early induction of the C4 PEPC phosphorylation cascade. U-73122, but not the inactive analogue U-73343, efficiently blocked the transient accumulation of Ins(1,4,5)P3, and both the increase in C4 PEPC kinase activity and C4 PEPC phosphorylation in illuminated and weak base-treated protoplasts. Taken together, these data suggest that PI-PLC-based signalling is a committed step in the cascade controlling the regulation of C4 PEPC phosphorylation in C4 leaves.
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An increase in phosphoinositide‐specific phospholipase C activity precedes induction of C4 phosphoenolpyruvate carboxylase phosphorylation in illuminated and NH4Cl‐treated protoplasts from Digitaria sanguinalis
Plant Journal, 2000Co-Authors: Sylvie Coursol, Jean Vidal, Nathalie Giglioli-guivarc’h, Jeannoel PierreAbstract:A Ca 2+ -dependent phosphoinositide-specific phospholipase C (PI-PLC) activity has been characterized in the microsomal fraction of Digitaria sanguinalis mesophyll cell protoplasts. Microsomal PI-PLC was found to be inhibited in vitro by a mammalian anti-PLC-δ1 antibody and by the aminosteroide U-73122, an inhibitor of PI-PLC activity in animal cells. In Western blot experiments, the antibody recognized an 85kDa protein in both microsomal protein extracts from mesophyll protoplasts and rat brain protein extracts containing the authentic enzyme. The involvement of the microsomal PI-PLC in the light-dependent transduction pathway leading to the phosphorylation of C4 phosphoenolpyruvate carboxylase (PEPC) was investigated in D. sanguinalis protoplasts. A transient increase in the PI-PLC reaction product inositol-1,4,5-trisphosphate (Ins(1,4,5)P 3 ) was observed in situ during early induction of the C4 PEPC phosphorylation cascade. U-73122, but not the inactive analogue U-73343, efficiently blocked the transient accumulation of Ins(1,4,5)P3, and both the increase in C4 PEPC kinase activity and C4 PEPC phosphorylation in illuminated and weak base-treated protoplasts. Taken together, these data suggest that PI-PLC-based signalling is a committed step in the cascade controlling the regulation of C4 PEPC phosphorylation in C4 leaves.