The Experts below are selected from a list of 219 Experts worldwide ranked by ideXlab platform
Sylvain Raffaele - One of the best experts on this subject based on the ideXlab platform.
-
A Chromosome-Scale Genome Assembly Resource for Myriosclerotinia sulcatula Infecting Sedge Grass ( Carex sp.)
Molecular Plant-Microbe Interactions, 2020Co-Authors: Stefan Kusch, Heba Ibrahim, Catherine Zanchetta, Celine Lopez-roques, Cécile Donnadieu, Sylvain RaffaeleAbstract:The fungus Myriosclerotinia sulcatula is a close relative of the notorious polyphagous plant pathogens Botrytis cinerea and Sclerotinia sclerotiorum but exhibits a host range restricted to plants from the Carex genus (Cyperaceae family). To date, there are no genomic resources available for fungi in the Myriosclerotinia genus. Here, we present a chromosome-scale reference genome assembly for M. sulcatula. The assembly contains 24 contigs with a total length of 43.53 Mbp, with scaffold N50 of 2,649.7 kbp and N90 of 1,133.1 kbp. BRAKER-predicted gene models were manually curated using WebApollo, resulting in 11,275 protein-coding genes that we functionally annotated. We provide a high-quality reference genome assembly and annotation for M. sulcatula as a resource for studying evolution and pathogenicity in fungi from the Sclerotiniaceae family.
-
shifts in diversification rates and host jump frequencies shaped the diversity of host range among Sclerotiniaceae fungal plant pathogens
Molecular Ecology, 2018Co-Authors: Olivier Navaud, Adelin Barbacci, Andrew Taylor, John P Clarkson, Sylvain RaffaeleAbstract:The range of hosts that a parasite can infect in nature is a trait determined by its own evolutionary history and that of its potential hosts. However, knowledge on host range diversity and evolution at the family level is often lacking. Here, we investigate host range variation and diversification trends within the Sclerotiniaceae, a family of Ascomycete fungi. Using a phylogenetic framework, we associate diversification rates, the frequency of host jump events and host range variation during the evolution of this family. Variations in diversification rate during the evolution of the Sclerotiniaceae define three major macro-evolutionary regimes with contrasted proportions of species infecting a broad range of hosts. Host-parasite cophylogenetic analyses pointed towards parasite radiation on distant hosts long after host speciation (host jump or duplication events) as the dominant mode of association with plants in the Sclerotiniaceae. The intermediate macro-evolutionary regime showed a low diversification rate, high frequency of duplication events and the highest proportion of broad host range species. Our findings suggest that the emergence of broad host range fungal pathogens results largely from host jumps, as previously reported for oomycete parasites, probably combined with low speciation rates. These results have important implications for our understanding of fungal parasites evolution and are of particular relevance for the durable management of disease epidemics.
-
Common protein sequence signatures associate with Sclerotinia borealis lifestyle and secretion in fungal pathogens of the Sclerotiniaceae.
Frontiers in Plant Science, 2015Co-Authors: Thomas Badet, Rémi Peyraud, Sylvain RaffaeleAbstract:Fungal plant pathogens produce secreted proteins adapted to function outside fungal cells to facilitate colonization of their hosts. In many cases such as for fungi from the Sclerotiniaceae family the repertoire and function of secreted proteins remains elusive. In the Sclerotiniaceae, whereas Sclerotinia sclerotiorum and Botrytis cinerea are cosmopolitan broad host-range plant pathogens, Sclerotinia borealis has a psychrophilic lifestyle with a low optimal growth temperature, a narrow host range and geographic distribution. To spread successfully, S. borealis must synthesize proteins adapted to function in its specific environment. The search for signatures of adaptation to S. borealis lifestyle may therefore help revealing proteins critical for colonization of the environment by Sclerotiniaceae fungi. Here, we analyzed amino acids usage and intrinsic protein disorder in alignments of groups of orthologous proteins from the three Sclerotiniaceae species. We found that enrichment in Thr, depletion in Glu and Lys, and low disorder frequency in hot loops are significantly associated with S. borealis proteins. We designed an index to report bias in these properties and found that high index proteins were enriched among secreted proteins in the three Sclerotiniaceae fungi. High index proteins were also enriched in function associated with plant colonization in S. borealis, and in in planta-induced genes in S. sclerotiorum. We highlight a novel putative antifreeze protein and a novel putative lytic polysaccharide monooxygenase identified through our pipeline as candidate proteins involved in colonization of the environment. Our findings suggest that similar protein signatures associate with S. borealis lifestyle and with secretion in the Sclerotiniaceae. These signatures may be useful for identifying proteins of interest as targets for the management of plant diseases.
Monica Höfte - One of the best experts on this subject based on the ideXlab platform.
-
enhancement of fungicidal and insecticidal activity by reductive alkylation of chitosan
Pest Management Science, 2006Co-Authors: Entsar I Rabea, Mohamed E I Badawy, Tina Rogge, Christian V. Stevens, Monica Höfte, Walter Steurbaut, Guy SmaggheAbstract:A series of N-alkyl chitosan (NAC) derivatives were synthesized using a reductive alkylation reaction to examine their fungicidal and insecticidal activity. The chemical structures were characterized by IR and 1H NMR spectroscopy, and the degree of substitution (DS) ranged from 0.02 to 0.37. Their fungicidal activity was evaluated against the grey mould Botrytis cinerea Pers ex Fr (Leotiales: Sclerotiniaceae) and the rice leaf blast pathogen Pyricularia grisea Sacc [Teleomorph: Magnaporthe grisea (Hebert) Barr] by a radial growth bioassay. It was of interest that most of the NAC derivatives were more active against both fungi than chitosan itself. The most active derivative was N-(2,2-diphenylethyl)chitosan with EC50 values of 0.031 and 0.23 g L−1 against B. cinerea and P. grisea respectively. In addition, some derivatives, at higher concentrations up to 1.0 g L−1, inhibited the mycelial growth and spore formation of P. grisea. Bioassays against larvae of the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) with the NAC derivatives at a rate of 5.0 g kg−1 in artificial diet demonstrated that N-(3-phenylbutyl)chitosan was the most active compound. In addition, N-propylchitosan, N-undecanylchitosan and N-(3-phenylpropyl)chitosan derivatives strongly inhibited larval weight gain in S. littoralis, with respective reductions of 76, 66 and 65% after 4 days of feeding on treated diet. Copyright © 2006 Society of Chemical Industry
-
insecticidal and fungicidal activity of new synthesized chitosan derivatives
Pest Management Science, 2005Co-Authors: Entsar I Rabea, Mohamed E I Badawy, Tina Rogge, Christian V. Stevens, Monica Höfte, Walter Steurbaut, Guy SmaggheAbstract:Chitosan, the N-deacetylated derivative of chitin, is a potential biopolysaccharide owing to its specific structure and properties. In this paper, we report on the synthesis of 24 new chitosan derivatives, N-alkyl chitosans (NAC) and N-benzyl chitosans (NBC), that are soluble in dilute aqueous acetic acid. The different derivatives were synthesized by reductive amination and analyzed by 1 H NMR spectroscopy. A high degree of substitution (DS) was obtained with N-(butyl)chitosan (DS 0.36) at a 1:1 mole ratio for NAC derivatives and N-(2,4-dichlorobenzyl)chitosan (DS 0.52) for NBC derivatives. Their insecticidal and fungicidal activities were tested against larvae of the cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae), the grey mould Botrytis cinerea Pers (Leotiales: Sclerotiniaceae) and the rice leaf blast Pyricularia grisea Cavara (Teleomorph: Magnaporthe grisea (Hebert) Barr). The oral feeding bioassay indicated that all the derivatives had significant insecticidal activity at 5gkg −1 in artificial diet. The most active wasN-(2-chloro-6-fluorobenzyl)chitosan, which caused 100% mortality at 0.625gkg −1 , with an estimated LC50 of 0.32gkg −1 . Treated larvae ceased feeding after 2-3days; the mechanism of action remains unknown. In a radial hyphal growth bioassay with both plant pathogens, all derivatives showed a higher fungicidal action than chitosan. N-Dodecylchitosan, N-(p-isopropylbenzyl)chitosan and N-(2,6-dichlorobenzyl)chitosan were the most active against B cinerea ,w ith EC50 values of 0.57, 0.57 and 0.52glitre −1 , respectively. Against Pg risea, N-(m-nitrobenzyl)chitosan was the most active, with 77% inhibition at 5glitre −1 . The effect of different substitutions is discussed in relation to insecticidal and
-
fungicidal and insecticidal activity of o acyl chitosan derivatives
Polymer Bulletin, 2005Co-Authors: Mohamed E I Badawy, Entsar I Rabea, Tina Rogge, Christian V. Stevens, Monica Höfte, Walter Steurbaut, Guy SmaggheAbstract:A series of O-(acyl) chitosan (OAC) derivatives with a degree of substitution (DS) between 0.02 and 0.28 were synthesized by reaction of alkanoic acid derivatives with chitosan in the presence of H2SO4 as a catalyst. The reaction was performed at 80 °C for 4 h with different mol ratios of alkanoic acids to chitosan. The synthesized compounds were analyzed by 1H- and 13C-NMR spectroscopy. A high DS was obtained with O-(butyroyl) chitosan (DS 0.28) at a mol ratio of (1:5) chitosan to butyric acid. Their fungicidal activity against the grey mould Botrytis cinerea (Leotiales: Sclerotiniaceae) and the rice leaf blast pathogen Pyricularia grisea (Teleomorph: Magnaportha grisea) has been evaluated. O-(decanoyl) chitosan at mol ratio of 1:2 (chitosan to decanoic acid) was the most active compound against B. cinerea (EC50=1.02 g.l-1) and O-(hexanoyl) chitosan displayed the highest activity against P. grisea (EC50=1.11 g.l-1). It has been mentioned that some derivatives also repressed spore formation at rather high concentrations (1.0, 2.0 and 5.0 g.l-1). The insecticidal activity has been screened at 5 g.kg-1 artificial diet against the larvae of the cotton leafworm Spodoptera littoralis (Lepidoptera: Noctuidae). The results revealed that all of the synthesized derivatives showed high inhibition of growth of the larvae of S. littoralis compared to chitosan (7% growth inhibition) and the most active one was O-(decanoyl) chitosan (64% growth inhibition) after 5 days of feeding on treated artificial diet.
-
synthesis and fungicidal activity of new n o acyl chitosan derivatives
Biomacromolecules, 2004Co-Authors: Mohamed E I Badawy, Entsar I Rabea, Tina Rogge, Christian V. Stevens, Walter Steurbaut, Guy Smagghe, Monica HöfteAbstract:Novel N,O-acyl chitosan (NOAC) derivatives were synthesized to examine their fungicidal activity against the gray mould fungus Botrytis cinerea (Leotiales: Sclerotiniaceae) and the rice leaf blast fungus Pyricularia oryzae (Teleomorph: Magnaporth grisea). The fungicidal activity was evaluated by the radial growth bioassay. NOAC derivatives were more active against the two plant pathogens than chitosan itself, and the effect was concentration dependent. Against B. cinerea, 4-chlorobutyryl chitosan (EC50 = 0.043%), decanoyl chitosan (EC50 = 0.044%), cinnamoyl chitosan (EC50 = 0.045%), and p-methoxybenzoyl chitosan (EC50 = 0.050%) were the most active (12−13-fold more active than chitosan). (Un)-substituted benzoyl chitosan derivatives were more active against B. cinerea than most of these with N,O-alkyl derivatives. Against P. oryzae chitosan derivatives with lauroyl, methoxy acetyl, methacryloyl and decanoyl were the most active.
-
synthesis and fungicidal activity of new n o acyl chitosan derivatives
Biomacromolecules, 2004Co-Authors: Mohamed E I Badawy, Entsar I Rabea, Tina Rogge, Christian V. Stevens, Walter Steurbaut, Guy Smagghe, Monica HöfteAbstract:Novel N,O-acyl chitosan (NOAC) derivatives were synthesized to examine their fungicidal activity against the gray mould fungus Botrytis cinerea (Leotiales: Sclerotiniaceae) and the rice leaf blast fungus Pyricularia oryzae (Teleomorph: Magnaporth grisea). The fungicidal activity was evaluated by the radial growth bioassay. NOAC derivatives were more active against the two plant pathogens than chitosan itself, and the effect was concentration dependent. Against B. cinerea, 4-chlorobutyryl chitosan (EC50 = 0.043%), decanoyl chitosan (EC50 = 0.044%), cinnamoyl chitosan (EC50 = 0.045%), and p-methoxybenzoyl chitosan (EC50 = 0.050%) were the most active (12−13-fold more active than chitosan). (Un)-substituted benzoyl chitosan derivatives were more active against B. cinerea than most of these with N,O-alkyl derivatives. Against P. oryzae chitosan derivatives with lauroyl, methoxy acetyl, methacryloyl and decanoyl were the most active.
Guy Smagghe - One of the best experts on this subject based on the ideXlab platform.
-
enhancement of fungicidal and insecticidal activity by reductive alkylation of chitosan
Pest Management Science, 2006Co-Authors: Entsar I Rabea, Mohamed E I Badawy, Tina Rogge, Christian V. Stevens, Monica Höfte, Walter Steurbaut, Guy SmaggheAbstract:A series of N-alkyl chitosan (NAC) derivatives were synthesized using a reductive alkylation reaction to examine their fungicidal and insecticidal activity. The chemical structures were characterized by IR and 1H NMR spectroscopy, and the degree of substitution (DS) ranged from 0.02 to 0.37. Their fungicidal activity was evaluated against the grey mould Botrytis cinerea Pers ex Fr (Leotiales: Sclerotiniaceae) and the rice leaf blast pathogen Pyricularia grisea Sacc [Teleomorph: Magnaporthe grisea (Hebert) Barr] by a radial growth bioassay. It was of interest that most of the NAC derivatives were more active against both fungi than chitosan itself. The most active derivative was N-(2,2-diphenylethyl)chitosan with EC50 values of 0.031 and 0.23 g L−1 against B. cinerea and P. grisea respectively. In addition, some derivatives, at higher concentrations up to 1.0 g L−1, inhibited the mycelial growth and spore formation of P. grisea. Bioassays against larvae of the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) with the NAC derivatives at a rate of 5.0 g kg−1 in artificial diet demonstrated that N-(3-phenylbutyl)chitosan was the most active compound. In addition, N-propylchitosan, N-undecanylchitosan and N-(3-phenylpropyl)chitosan derivatives strongly inhibited larval weight gain in S. littoralis, with respective reductions of 76, 66 and 65% after 4 days of feeding on treated diet. Copyright © 2006 Society of Chemical Industry
-
insecticidal and fungicidal activity of new synthesized chitosan derivatives
Pest Management Science, 2005Co-Authors: Entsar I Rabea, Mohamed E I Badawy, Tina Rogge, Christian V. Stevens, Monica Höfte, Walter Steurbaut, Guy SmaggheAbstract:Chitosan, the N-deacetylated derivative of chitin, is a potential biopolysaccharide owing to its specific structure and properties. In this paper, we report on the synthesis of 24 new chitosan derivatives, N-alkyl chitosans (NAC) and N-benzyl chitosans (NBC), that are soluble in dilute aqueous acetic acid. The different derivatives were synthesized by reductive amination and analyzed by 1 H NMR spectroscopy. A high degree of substitution (DS) was obtained with N-(butyl)chitosan (DS 0.36) at a 1:1 mole ratio for NAC derivatives and N-(2,4-dichlorobenzyl)chitosan (DS 0.52) for NBC derivatives. Their insecticidal and fungicidal activities were tested against larvae of the cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae), the grey mould Botrytis cinerea Pers (Leotiales: Sclerotiniaceae) and the rice leaf blast Pyricularia grisea Cavara (Teleomorph: Magnaporthe grisea (Hebert) Barr). The oral feeding bioassay indicated that all the derivatives had significant insecticidal activity at 5gkg −1 in artificial diet. The most active wasN-(2-chloro-6-fluorobenzyl)chitosan, which caused 100% mortality at 0.625gkg −1 , with an estimated LC50 of 0.32gkg −1 . Treated larvae ceased feeding after 2-3days; the mechanism of action remains unknown. In a radial hyphal growth bioassay with both plant pathogens, all derivatives showed a higher fungicidal action than chitosan. N-Dodecylchitosan, N-(p-isopropylbenzyl)chitosan and N-(2,6-dichlorobenzyl)chitosan were the most active against B cinerea ,w ith EC50 values of 0.57, 0.57 and 0.52glitre −1 , respectively. Against Pg risea, N-(m-nitrobenzyl)chitosan was the most active, with 77% inhibition at 5glitre −1 . The effect of different substitutions is discussed in relation to insecticidal and
-
fungicidal and insecticidal activity of o acyl chitosan derivatives
Polymer Bulletin, 2005Co-Authors: Mohamed E I Badawy, Entsar I Rabea, Tina Rogge, Christian V. Stevens, Monica Höfte, Walter Steurbaut, Guy SmaggheAbstract:A series of O-(acyl) chitosan (OAC) derivatives with a degree of substitution (DS) between 0.02 and 0.28 were synthesized by reaction of alkanoic acid derivatives with chitosan in the presence of H2SO4 as a catalyst. The reaction was performed at 80 °C for 4 h with different mol ratios of alkanoic acids to chitosan. The synthesized compounds were analyzed by 1H- and 13C-NMR spectroscopy. A high DS was obtained with O-(butyroyl) chitosan (DS 0.28) at a mol ratio of (1:5) chitosan to butyric acid. Their fungicidal activity against the grey mould Botrytis cinerea (Leotiales: Sclerotiniaceae) and the rice leaf blast pathogen Pyricularia grisea (Teleomorph: Magnaportha grisea) has been evaluated. O-(decanoyl) chitosan at mol ratio of 1:2 (chitosan to decanoic acid) was the most active compound against B. cinerea (EC50=1.02 g.l-1) and O-(hexanoyl) chitosan displayed the highest activity against P. grisea (EC50=1.11 g.l-1). It has been mentioned that some derivatives also repressed spore formation at rather high concentrations (1.0, 2.0 and 5.0 g.l-1). The insecticidal activity has been screened at 5 g.kg-1 artificial diet against the larvae of the cotton leafworm Spodoptera littoralis (Lepidoptera: Noctuidae). The results revealed that all of the synthesized derivatives showed high inhibition of growth of the larvae of S. littoralis compared to chitosan (7% growth inhibition) and the most active one was O-(decanoyl) chitosan (64% growth inhibition) after 5 days of feeding on treated artificial diet.
-
synthesis and fungicidal activity of new n o acyl chitosan derivatives
Biomacromolecules, 2004Co-Authors: Mohamed E I Badawy, Entsar I Rabea, Tina Rogge, Christian V. Stevens, Walter Steurbaut, Guy Smagghe, Monica HöfteAbstract:Novel N,O-acyl chitosan (NOAC) derivatives were synthesized to examine their fungicidal activity against the gray mould fungus Botrytis cinerea (Leotiales: Sclerotiniaceae) and the rice leaf blast fungus Pyricularia oryzae (Teleomorph: Magnaporth grisea). The fungicidal activity was evaluated by the radial growth bioassay. NOAC derivatives were more active against the two plant pathogens than chitosan itself, and the effect was concentration dependent. Against B. cinerea, 4-chlorobutyryl chitosan (EC50 = 0.043%), decanoyl chitosan (EC50 = 0.044%), cinnamoyl chitosan (EC50 = 0.045%), and p-methoxybenzoyl chitosan (EC50 = 0.050%) were the most active (12−13-fold more active than chitosan). (Un)-substituted benzoyl chitosan derivatives were more active against B. cinerea than most of these with N,O-alkyl derivatives. Against P. oryzae chitosan derivatives with lauroyl, methoxy acetyl, methacryloyl and decanoyl were the most active.
-
synthesis and fungicidal activity of new n o acyl chitosan derivatives
Biomacromolecules, 2004Co-Authors: Mohamed E I Badawy, Entsar I Rabea, Tina Rogge, Christian V. Stevens, Walter Steurbaut, Guy Smagghe, Monica HöfteAbstract:Novel N,O-acyl chitosan (NOAC) derivatives were synthesized to examine their fungicidal activity against the gray mould fungus Botrytis cinerea (Leotiales: Sclerotiniaceae) and the rice leaf blast fungus Pyricularia oryzae (Teleomorph: Magnaporth grisea). The fungicidal activity was evaluated by the radial growth bioassay. NOAC derivatives were more active against the two plant pathogens than chitosan itself, and the effect was concentration dependent. Against B. cinerea, 4-chlorobutyryl chitosan (EC50 = 0.043%), decanoyl chitosan (EC50 = 0.044%), cinnamoyl chitosan (EC50 = 0.045%), and p-methoxybenzoyl chitosan (EC50 = 0.050%) were the most active (12−13-fold more active than chitosan). (Un)-substituted benzoyl chitosan derivatives were more active against B. cinerea than most of these with N,O-alkyl derivatives. Against P. oryzae chitosan derivatives with lauroyl, methoxy acetyl, methacryloyl and decanoyl were the most active.
Mohamed E I Badawy - One of the best experts on this subject based on the ideXlab platform.
-
enhancement of fungicidal and insecticidal activity by reductive alkylation of chitosan
Pest Management Science, 2006Co-Authors: Entsar I Rabea, Mohamed E I Badawy, Tina Rogge, Christian V. Stevens, Monica Höfte, Walter Steurbaut, Guy SmaggheAbstract:A series of N-alkyl chitosan (NAC) derivatives were synthesized using a reductive alkylation reaction to examine their fungicidal and insecticidal activity. The chemical structures were characterized by IR and 1H NMR spectroscopy, and the degree of substitution (DS) ranged from 0.02 to 0.37. Their fungicidal activity was evaluated against the grey mould Botrytis cinerea Pers ex Fr (Leotiales: Sclerotiniaceae) and the rice leaf blast pathogen Pyricularia grisea Sacc [Teleomorph: Magnaporthe grisea (Hebert) Barr] by a radial growth bioassay. It was of interest that most of the NAC derivatives were more active against both fungi than chitosan itself. The most active derivative was N-(2,2-diphenylethyl)chitosan with EC50 values of 0.031 and 0.23 g L−1 against B. cinerea and P. grisea respectively. In addition, some derivatives, at higher concentrations up to 1.0 g L−1, inhibited the mycelial growth and spore formation of P. grisea. Bioassays against larvae of the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) with the NAC derivatives at a rate of 5.0 g kg−1 in artificial diet demonstrated that N-(3-phenylbutyl)chitosan was the most active compound. In addition, N-propylchitosan, N-undecanylchitosan and N-(3-phenylpropyl)chitosan derivatives strongly inhibited larval weight gain in S. littoralis, with respective reductions of 76, 66 and 65% after 4 days of feeding on treated diet. Copyright © 2006 Society of Chemical Industry
-
insecticidal and fungicidal activity of new synthesized chitosan derivatives
Pest Management Science, 2005Co-Authors: Entsar I Rabea, Mohamed E I Badawy, Tina Rogge, Christian V. Stevens, Monica Höfte, Walter Steurbaut, Guy SmaggheAbstract:Chitosan, the N-deacetylated derivative of chitin, is a potential biopolysaccharide owing to its specific structure and properties. In this paper, we report on the synthesis of 24 new chitosan derivatives, N-alkyl chitosans (NAC) and N-benzyl chitosans (NBC), that are soluble in dilute aqueous acetic acid. The different derivatives were synthesized by reductive amination and analyzed by 1 H NMR spectroscopy. A high degree of substitution (DS) was obtained with N-(butyl)chitosan (DS 0.36) at a 1:1 mole ratio for NAC derivatives and N-(2,4-dichlorobenzyl)chitosan (DS 0.52) for NBC derivatives. Their insecticidal and fungicidal activities were tested against larvae of the cotton leafworm Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae), the grey mould Botrytis cinerea Pers (Leotiales: Sclerotiniaceae) and the rice leaf blast Pyricularia grisea Cavara (Teleomorph: Magnaporthe grisea (Hebert) Barr). The oral feeding bioassay indicated that all the derivatives had significant insecticidal activity at 5gkg −1 in artificial diet. The most active wasN-(2-chloro-6-fluorobenzyl)chitosan, which caused 100% mortality at 0.625gkg −1 , with an estimated LC50 of 0.32gkg −1 . Treated larvae ceased feeding after 2-3days; the mechanism of action remains unknown. In a radial hyphal growth bioassay with both plant pathogens, all derivatives showed a higher fungicidal action than chitosan. N-Dodecylchitosan, N-(p-isopropylbenzyl)chitosan and N-(2,6-dichlorobenzyl)chitosan were the most active against B cinerea ,w ith EC50 values of 0.57, 0.57 and 0.52glitre −1 , respectively. Against Pg risea, N-(m-nitrobenzyl)chitosan was the most active, with 77% inhibition at 5glitre −1 . The effect of different substitutions is discussed in relation to insecticidal and
-
fungicidal and insecticidal activity of o acyl chitosan derivatives
Polymer Bulletin, 2005Co-Authors: Mohamed E I Badawy, Entsar I Rabea, Tina Rogge, Christian V. Stevens, Monica Höfte, Walter Steurbaut, Guy SmaggheAbstract:A series of O-(acyl) chitosan (OAC) derivatives with a degree of substitution (DS) between 0.02 and 0.28 were synthesized by reaction of alkanoic acid derivatives with chitosan in the presence of H2SO4 as a catalyst. The reaction was performed at 80 °C for 4 h with different mol ratios of alkanoic acids to chitosan. The synthesized compounds were analyzed by 1H- and 13C-NMR spectroscopy. A high DS was obtained with O-(butyroyl) chitosan (DS 0.28) at a mol ratio of (1:5) chitosan to butyric acid. Their fungicidal activity against the grey mould Botrytis cinerea (Leotiales: Sclerotiniaceae) and the rice leaf blast pathogen Pyricularia grisea (Teleomorph: Magnaportha grisea) has been evaluated. O-(decanoyl) chitosan at mol ratio of 1:2 (chitosan to decanoic acid) was the most active compound against B. cinerea (EC50=1.02 g.l-1) and O-(hexanoyl) chitosan displayed the highest activity against P. grisea (EC50=1.11 g.l-1). It has been mentioned that some derivatives also repressed spore formation at rather high concentrations (1.0, 2.0 and 5.0 g.l-1). The insecticidal activity has been screened at 5 g.kg-1 artificial diet against the larvae of the cotton leafworm Spodoptera littoralis (Lepidoptera: Noctuidae). The results revealed that all of the synthesized derivatives showed high inhibition of growth of the larvae of S. littoralis compared to chitosan (7% growth inhibition) and the most active one was O-(decanoyl) chitosan (64% growth inhibition) after 5 days of feeding on treated artificial diet.
-
synthesis and fungicidal activity of new n o acyl chitosan derivatives
Biomacromolecules, 2004Co-Authors: Mohamed E I Badawy, Entsar I Rabea, Tina Rogge, Christian V. Stevens, Walter Steurbaut, Guy Smagghe, Monica HöfteAbstract:Novel N,O-acyl chitosan (NOAC) derivatives were synthesized to examine their fungicidal activity against the gray mould fungus Botrytis cinerea (Leotiales: Sclerotiniaceae) and the rice leaf blast fungus Pyricularia oryzae (Teleomorph: Magnaporth grisea). The fungicidal activity was evaluated by the radial growth bioassay. NOAC derivatives were more active against the two plant pathogens than chitosan itself, and the effect was concentration dependent. Against B. cinerea, 4-chlorobutyryl chitosan (EC50 = 0.043%), decanoyl chitosan (EC50 = 0.044%), cinnamoyl chitosan (EC50 = 0.045%), and p-methoxybenzoyl chitosan (EC50 = 0.050%) were the most active (12−13-fold more active than chitosan). (Un)-substituted benzoyl chitosan derivatives were more active against B. cinerea than most of these with N,O-alkyl derivatives. Against P. oryzae chitosan derivatives with lauroyl, methoxy acetyl, methacryloyl and decanoyl were the most active.
-
synthesis and fungicidal activity of new n o acyl chitosan derivatives
Biomacromolecules, 2004Co-Authors: Mohamed E I Badawy, Entsar I Rabea, Tina Rogge, Christian V. Stevens, Walter Steurbaut, Guy Smagghe, Monica HöfteAbstract:Novel N,O-acyl chitosan (NOAC) derivatives were synthesized to examine their fungicidal activity against the gray mould fungus Botrytis cinerea (Leotiales: Sclerotiniaceae) and the rice leaf blast fungus Pyricularia oryzae (Teleomorph: Magnaporth grisea). The fungicidal activity was evaluated by the radial growth bioassay. NOAC derivatives were more active against the two plant pathogens than chitosan itself, and the effect was concentration dependent. Against B. cinerea, 4-chlorobutyryl chitosan (EC50 = 0.043%), decanoyl chitosan (EC50 = 0.044%), cinnamoyl chitosan (EC50 = 0.045%), and p-methoxybenzoyl chitosan (EC50 = 0.050%) were the most active (12−13-fold more active than chitosan). (Un)-substituted benzoyl chitosan derivatives were more active against B. cinerea than most of these with N,O-alkyl derivatives. Against P. oryzae chitosan derivatives with lauroyl, methoxy acetyl, methacryloyl and decanoyl were the most active.
Anantanarayanan Raman - One of the best experts on this subject based on the ideXlab platform.
-
botrytis cinerea helotiales Sclerotiniaceae induced changes in vitis vinifera vitales vitaceae leaves influence the oviposition behaviour and life history of epiphyas postvittana lepidoptera tortricidae
Ethology Ecology & Evolution, 2017Co-Authors: Syed Rizvi, Anantanarayanan RamanAbstract:Insects use sensory cues to select plants for feeding and oviposition. For a better offspring survival and life-history performance, the oviposition-site selection by gravid females usually corresponds with plant suitability for the best offspring development. To test this, we used the three-component interacting system involving Botrytis cinerea, a pathogenic fungus on Vitis vinifera, and the plant-feeding Epiphyas postvittana. We hypothesised that the gravid females of E. postvittana discriminate between B. cinerea-infected and uninfected leaves of V. vinifera for oviposition to maximise their offspring performance. We characterised volatiles from B. cinerea-infected and uninfected leaves of V. vinifera. We tested the effect of volatiles from B. cinerea-infected leaves on the olfactory behaviour of E. postvittana using a wind-tunnel assay. We raised the neonate larvae of E. postvittana on B. cinerea-infected and uninfected leaves to characterise their development and life-history performance. The key vo...
-
oviposition preference and larval performance of epiphyas postvittana lepidoptera tortricidae on botrytis cinerea helotiales Sclerotiniaceae infected berries of vitis vinifera vitales vitaceae
Insect Science, 2016Co-Authors: Syed Rizvi, Anantanarayanan Raman, Warwick Wheatley, Geoffrey CookAbstract:在这份报纸，我们在为因此有益于后代性能的 oviposition 选择大多数适当的地点测试了怀孕 Epiphyas postvittana 的行为。我们的假设在 Jaenikes 偏爱表演假设上被造(也叫作 “mother-knows-the-best”假设) 。测试这，我们使用了交往的 Epiphyas postvittana，它的主人 Vitis vinifera，和病原的微生物 Botrytis cinerea 系统。E 的人口。postvittana 和 B。cinerea 经常在 V 上并发地存在。在澳大利西亚和他们的相互作用和相互的影响的 vinifera 当前正在被探索，尽管建议目前是在 E 之间的关系。postvittana 和 B。cinerea 是 mutualistic。我们从 B 测试了 volatiles 的效果。感染 cinerea 的果浆和 uninfected (控制) V 的果浆。E 的 oviposition 行为上的 vinifera。postvittana。我们也描绘了 B 的效果。V 的果浆上的 cinerea 感染。E 的生长和发展上的 vinifera。postvittana。与偏爱表演假设相反， oviposition 选择由怀孕 E 做了。postvittana 没导致最好的后代幸存，开发，和性能。为由 E 的 oviposition 的偏爱。postvittana 被嗅觉、触觉的暗示强烈影响。她在 B 上生了更少鸡蛋。与 V 的 uninfected 果浆相比的感染 cinerea 的果浆。vinifera。E 的幼虫。postvittana 没显示出偏爱到 V 的 uninfected 果浆。vinifera。在 B 上喂的幼虫。V 的感染 cinerea 的果浆。显示出更大的幸存率的 vinifera，化蛹的更短的时间，更大的蛹的质量，并且在成为成年人以后，他们比被使能在 uninfected 上喂果浆的幼虫放了鸡蛋的更多的数字。E 的幼虫。postvittana 运输 B 的 conidia。cinerea 并且把灰模子的疾病传给 V 的 uninfected 果浆。vinifera。
-
oviposition preference and larval performance of epiphyas postvittana lepidoptera tortricidae on botrytis cinerea helotiales Sclerotiniaceae infected berries of vitis vinifera vitales vitaceae
Insect Science, 2016Co-Authors: Syed Rizvi, Anantanarayanan Raman, Warwick Wheatley, Geoffrey CookAbstract:In this paper we tested the behavior of gravid Epiphyas postvittana in select- ing the most-appropriate site for oviposition thus benefitting offspring performance. Our hypothesis was built on Jaenike's preference-performance hypothesis (also referred to as the "mother-knows-the-best" hypothesis). To test this, we used the interacting Epiphyas postvittana, its host Vitis vinifera, and the pathogenic microbe Botrytis cinerea system. Populations of E. postvittana and B. cinerea often exist concurrently on V. vinifera in Aus- tralasia and their interaction and mutual influence are currently being explored, although the suggestion presently is that the relationship between E. postvittana and B. cinerea is mutualistic. We tested the effect of volatiles from B. cinerea-infected berries and unin- fected (control) berries of V. vinifera on the oviposition behavior of E. postvittana .W e also characterized the effects of B. cinerea infection on the berries of V. vinifera on the growth and development of E. postvittana. Contrary to the preference-performance hy- pothesis, oviposition choices made by gravid E. postvittana did not result in the best offspring survival, development, and performance. The preference for oviposition by E.postvittanawasstrongly influenced bythe olfactory and tactile cues.Shelaid fewereggs on B. cinerea-infected berries compared to uninfected berries of V. vinifera. The larvae of E. postvittana showed no preference to uninfected berries of V. vinifera .T he larvae fed on B. cinerea-infected berries of V. vinifera showing greater survival rate, shorter time to pupation, greater pupal mass, and on becoming adults they laid more numbers of eggs than the larvae that were enabled to feed on uninfected berries. The larvae of E. postvittana transport the conidia of B. cinerea and transmit grey-mould disease to uninfected berries of V. vinifera.
-
epiphyas postvittana lepidoptera tortricidae botrytis cinerea helotiales Sclerotiniaceae vitis vinifera vitales vitaceae interaction the role of b cinerea on the development of e postvittana in synthetic nutritional media
Journal of Economic Entomology, 2015Co-Authors: Syed Rizvi, Anantanarayanan RamanAbstract:ABSTRACT Epiphyas postvittana (Walker) (light-brown apple moth) is a polyphagous herbivore of economic significance, which also feeds on Vitis vinifera L. The E. postvittana—V. vinifera interacting system also involves the participation of the fungus Botrytis cinerea Persoon ex Fries. We have been exploring the relationship among E. postvittana—V. vinifera—B. cinerea over the past two years. In this article, we report the preference and performance of the larvae of E. postvittana raised solely on a synthetic diet incorporated with the mycelial material of B. cinerea (Diet B). To characterize the effect of fungus on the development of E. postvittana, another synthetic diet was prepared that included the lyophilized leaf material of V. vinifera (Diet C). When raised on Diets B and C, a decrease in the duration of larval development and an increase in the survival and fecundity rate of E. postvittana occurred. Diet B influenced the pupal mass, but a significant increase occurred when the larvae were fed on D...
-
epiphyas postvittana lepidoptera tortricidae botrytis cinerea helotiales Sclerotiniaceae vitis vinifera vitales vitaceae interaction the role of b cinerea on the development of e postvittana in synthetic nutritional media
Journal of Economic Entomology, 2015Co-Authors: Syed Rizvi, Anantanarayanan RamanAbstract:Epiphyas postvittana (Walker) (light-brown apple moth) is a polyphagous herbivore of economic significance, which also feeds on Vitis vinifera L. The E. postvittana-V. vinifera interacting system also involves the participation of the fungus Botrytis cinerea Persoon ex Fries. We have been exploring the relationship among E. postvittana-V. vinifera-B. cinerea over the past two years. In this article, we report the preference and performance of the larvae of E. postvittana raised solely on a synthetic diet incorporated with the mycelial material of B. cinerea (Diet B). To characterize the effect of fungus on the development of E. postvittana, another synthetic diet was prepared that included the lyophilized leaf material of V. vinifera (Diet C). When raised on Diets B and C, a decrease in the duration of larval development and an increase in the survival and fecundity rate of E. postvittana occurred. Diet B influenced the pupal mass, but a significant increase occurred when the larvae were fed on Diet C. The larval emergence rate was the greatest in E. postvittana raised on Diet B, followed by those on Diet C. The F(2) generation of the larvae reared on Diet B showed similar effects as F(1) on the life-history performance of the larvae. Diet B enhanced the life-history performance of E. postvittana, although the larvae of E. postvittana showed little preference to Diet B. The greater fertility rate of E. postvittana reared on Diet B suggests the importance of sterols as shown in Lobesia botrana (Denis & Schiffermuller) (Lepidoptera: Tortricidae) and in a few Myrmicinae (Hymenoptera: Formicidae), which serve as precursors to different ecdysteroids that regulate many critical processes through embryonic development.