Rabab Elamawi - Academia.edu (original) (raw)

Papers by Rabab Elamawi

Egyptian Journal of Biological Pest Control, Mar 8, 2018

An efficient biosynthesis process for the rapid production of nanoparticles would enable the deve... more An efficient biosynthesis process for the rapid production of nanoparticles would enable the development of a "microbial nanotechnology" for mass-scale production. In the present research, biological silver nanoparticle was synthesized extracellularly by using the fungus, Trichoderma longibrachiatum, where the cell filtrate of the fungus was used as a reducing and stabilizing agent in the process of nanoparticle synthesis. Different physical parameters such as fungal biomass concentration (1, 5, 10, 15, and 20 g), temperature (25, 28, and 33°C), incubation time (0-120 h) , and agitation (shaken or not shaken) were investigated, in order to determine the optimal conditions for nanoparticle biosynthesis. The stability and antifungal properties of the synthesized silver nanoparticles (AgNPs) were also determined. Data revealed that a combination of 10 g fungal biomass, a reaction temperature of 28°C, a 72-h incubation time, and without shaking were the optimum conditions for the synthesis of the silver nanoparticles. Visual observation of brown color is an indication of silver nanoparticle production. UV-vis spectroscopy showed maximum absorption at 385 nm with the optimum conditions. Transmission electron microscopy (TEM) revealed the formation of monodispersed spherical shape with a mean diameter of 10 nm. Fourier transformation infrared (FTIR) showed bands at1634.92 and 3269. 31 cm −1. Dynamic light scattering (DLS) supported that the Z-average size was 24.43 and 0.420 PdI value. Zeta potential showed − 19.7 mV with a single peak. The AgNPs synthesized through this biosystem approach were relatively stable up to 2 months after synthesis. The use of AgNPs as antifungal led to significant reductions in the number of forming colonies for many plant pathogenic fungi, with efficiencies reaching up to 90% against Fusarium verticillioides, Fusarium moniliforme, Penicillium brevicompactum, Helminthosporium oryzae, and Pyricularia grisea. However, further research should be carried out in order to determine the toxic effect of AgNPs before mass production and use of agricultural applications.

Egyptian Journal of Botany, Jan 8, 2024

Journal of Plant Protection and Pathology, 2010

Rice is the second staple food crop after wheat in Egypt. White tip disease of rice leaves induce... more Rice is the second staple food crop after wheat in Egypt. White tip disease of rice leaves induced by the rice leaf nematode, Aphelenchoides besseyi (Christie, 1942), is widespread nearly in all rice ecosystems all over the world, causing remarkable yield reduction to susceptible cultivars. The losses reach to 47% in Egyptian rice Reiho cultivar. Rice seeds are known as the main source of the disease. The present study was conducted to evaluate the effect of seed priming on white tip nematode infection in rice and seed-borne fungi at different plant growth stages. Severely-infected Reiho rice seeds were primed for 48 hr in solutions of NaCl, CaCl2, Na2CO3, MgSO4, CuSO4 and micronized sulfur, separately or in mixtures of two salts except for the sulfur treatment. The primed seeds and the corresponding control nonprimed counterparts were then rinsed for three times using tap water and incubated at 30 o C to asses the germination percentage, which ranged between 96 to 100% with no significant difference between the primed and non-primed seed treatments. In the lab testing, the maximum seedling vigor index and root / shoot ratio were obtained using seedlings raised from seeds primed with 5 g/L solutions of sulfur (80%WP) followed by sulfur + CaCl2, NaCl and CuSO4. At nursery level, root/shoot ratio increased with all primed seed treatments except with those treated with NaCl solution. Two field experiments were conducted during the 2007and 2008 rice growing seasons. All seed priming treatments significantly enhanced most of the agronomic traits and increased yield in comparison with the non-primed infected or healthy seeds. Soaking in sulfur solution at the concentration of 5g/L and its combinations with the other salts at half dose of each gave the highest mortality of white tip nematode, lowest percentage of white tip infection, and least disease severity. Sulfur and NaCl is then proved to be the most effective priming mixture that can reduce white tip nematode infection. For seedborne fungi, the treatment with CaCl2 alone or in its all combinations has positive effects in elimination of the Fusarium Moniliforme, Helminthosporium oryzae and Alternaria padwickii in comparison with the water treatment control. CaCl2 completely eradiated F. moniliforme. Seed treatment with mixtures of salts reduced the fungal growth more than did one salt alone. Generally, all seeds primed with salts showed lower levels of infection with F. moniliforme comparing with the control. The treatment with CuSO4 solution at 1.5g/L gave complete protection from seed-borne fungi.

Environmental Science and Pollution Research, 2018

Due to the accelerating use of manufactured nanomaterials, more research is needed to define thei... more Due to the accelerating use of manufactured nanomaterials, more research is needed to define their impact on plants. The present investigation aimed at evaluating the effect of different levels (0.0, 10, 25, 50, and 100 mg/L) of ZnO nanoparticles (NPs) on Vicia faba during seed germination and seedling establishment. Additionally, V. faba root meristems were used as a model to monitor the cytotoxic and genotoxic effects resulting from exposure to ZnO NPs. The influence of ZnO NPs on three isoenzyme systems, peroxidase, α, and β esterase, was also evaluated using native-PAGE. Our results showed that lower concentrations of ZnO NPs (especially 10 and 25 mg/L) enhanced seed germination and improved seedling growth, while higher concentrations (100 and 200 mg/L) resulted in phytotoxicity. Cytological investigations of ZnO NPs-treated V. faba root cells denoted the clastogenic and aneugenic nature of ZnO NPs. Differential increase in mitotic index and significant alterations in cell cycle were observed upon exposure to ZnO NPs. High concentrations of ZnO NPs markedly induced chromosomal aberration, micronuclei, and vacuolated nuclei formation. Chromosomal breakage, chromosomal bridges, ring chromosomes, laggard chromosomes, and stickiness were also observed at a higher rate. The PAGE analysis showed that ZnO NPs treatments altered the expression patterns of all studied enzyme systems. Collectively, results from this work will help to further understand the phytotoxic effects of nanomaterials.

Journal of Molecular Modeling, 2016

Histone lysine acetylation is a reversible posttranslational modification that does not involve c... more Histone lysine acetylation is a reversible posttranslational modification that does not involve changes in DNA sequences. Enzymes play an important role in developmental processes and their deregulation has been linked to the progression of diverse disorders. The HAT enzyme family fulfills an important role in various developmental processes mediated by the state of chromatin, and have been attributed to its deregulation. To understand acetylation mechanisms and their role in cell signaling, transcriptional regulation, and apoptosis, it is crucial to identify and analyze acetylation sites. Bioinformatics methods can be used to generate relatively precise predictions. Here we applied classical bioinformatics methods-sequence alignment, homology modeling, and docking-to compare approved and predicted lysine acetylation processes in different organisms. HAM1 and HAM2 are analogs of KAT8 and KAT7 (MYST1 and MYST2), members of the MYST histone acetyltransferase family, and our results show that HAM1 and HAM2 have much in common with other representatives of MYST families from various organisms. One function of acetyl-CoA binding was predicted with a high level of probability by computational methods. Based on our data, we conclude that, despite huge genetic distances and some structural differences between animal and plant species, a closer look at acetylation mechanism shows that they have much in common.

Journal of Plant Protection and Pathology, 2016

The present study investigates the effect of zinc oxide nanoparticles (ZnO-NPs) on rice plants gr... more The present study investigates the effect of zinc oxide nanoparticles (ZnO-NPs) on rice plants growth and their role in management of brown spot disease caused by the causal agent Helmenthosporium oryza. The antifungal activity of ZnO-NPs (20 to 35 nm particle size) was evaluated at different concentrations. Spores germination percentage, colony formation and sporulation of H. oryza were reduced at concentrations 25 and 50 ppm, in vitro. The greenhouse results showed that seed soaking treatment and foliar spray 5 day before inoculation (DBI) of ZnO-NPs leaded to reduce infection percentage of brown spot without significant difference between ZnO-NPs concentrations. Foliar spray ٢ days post-inoculation (DPI) with the lower concentrations 10 and 25 ppm of ZnO-NPs were able to reduce infection percentage of brown spot. Under field conditions, During 2013 and 2014 seasons at El-sirw Agriculture Research Station, Dammietta, Egypt, rice varieties Giza 177, Giza 178 and Giza 179 under ZnO-NPs level (0, 10, 20 and 30 ppm) as foliar spray twice at mid tillering and panicle initiation stages were evaluated. Application of ZnO-NPs at level 20 ppm effectively reduced brown spot disease severity and discolored grains of all tested varieties. The studied rice varieties were varied in their growth, yield attributes, grain yield and brown spot severity whereas Giza 178 and Giza 179 had good performance under ZnO-NPs treatments. Therefore both Giza 178 and Giza 179 had showed significant salt tolerance at 20 ppm of ZnO-NPs. The performance of Giza 177 as a salinity-sensitive variety was improved at 20 ppm ZnO-NPs. The all ZnO-NPs treatment positively improved rice growth, yield attributes, rice grain yield and brown spot severity over control treatment. Finally, ZnO-NPs can be used as future "nanofertilizers".

Journal of Plant Protection and Pathology, 2016

The present study investigates the effect of zinc oxide nanoparticles (ZnO-NPs) on rice plants gr... more The present study investigates the effect of zinc oxide nanoparticles (ZnO-NPs) on rice plants growth and their role in management of brown spot disease caused by the causal agent Helmenthosporium oryza. The antifungal activity of ZnO-NPs (20 to 35 nm particle size) was evaluated at different concentrations. Spores germination percentage, colony formation and sporulation of H. oryza were reduced at concentrations 25 and 50 ppm, in vitro. The greenhouse results showed that seed soaking treatment and foliar spray 5 day before inoculation (DBI) of ZnO-NPs leaded to reduce infection percentage of brown spot without significant difference between ZnO-NPs concentrations. Foliar spray ٢ days post-inoculation (DPI) with the lower concentrations 10 and 25 ppm of ZnO-NPs were able to reduce infection percentage of brown spot. Under field conditions, During 2013 and 2014 seasons at El-sirw Agriculture Research Station, Dammietta, Egypt, rice varieties Giza 177, Giza 178 and Giza 179 under ZnO-NPs level (0, 10, 20 and 30 ppm) as foliar spray twice at mid tillering and panicle initiation stages were evaluated. Application of ZnO-NPs at level 20 ppm effectively reduced brown spot disease severity and discolored grains of all tested varieties. The studied rice varieties were varied in their growth, yield attributes, grain yield and brown spot severity whereas Giza 178 and Giza 179 had good performance under ZnO-NPs treatments. Therefore both Giza 178 and Giza 179 had showed significant salt tolerance at 20 ppm of ZnO-NPs. The performance of Giza 177 as a salinity-sensitive variety was improved at 20 ppm ZnO-NPs. The all ZnO-NPs treatment positively improved rice growth, yield attributes, rice grain yield and brown spot severity over control treatment. Finally, ZnO-NPs can be used as future "nanofertilizers".

This article cites 28 articles, 16 of which can be accessed free

Egyptian Journal of Phytopathology

ice blast caused by Magnaporthe oryzae is the major biotic stress influences rice yield. The curr... more ice blast caused by Magnaporthe oryzae is the major biotic stress influences rice yield. The current investigation aimed to estimate the antifungal activity and phytotoxicity effect of different concentrations of ZnO nanoparticles (0.0, 10, 25, 50, 100 and 200 mg/L) on M. oryzae and rice cultivar Sakha101 using morphological, biochemical and molecular markers. Five ISSR markers and seven RAPD primers were utilized to estimate the potentiality effects of ZnO nanoparticles (NPs). The effect of different rates and applications of ZnO NPs used to control rice blast disease and improve grain yield were estimated in the field during 2017 and 2018 growing seasons. The results showed that, in vitro antifungal assay of ZnO NPs showed a significant decrease in colony formation in comparison to control. Foliar application of ZnO NPs at 25 mg/L was the most effective treatments for mitigation rice blast at five days before inoculation. While under field conditions, foliar spray with 25 mg/L at nursery increased the grain yield to 4.366 ton/fed in season 2017 and to 4.625 ton/fed in 2018. Foliar spray with ZnO NPs of rice offer a practical and useful approach to improve rice grain yield and reduce leaf blast disease when applied at optimal concentrations. ZnO NPs at lower concentrations (10 and 25 mg/L) enhanced seed germination and improved seedling growth, while the higher concentrations (100 and 200 mg/L) resulted in phytotoxicity. ZnO NPs treatments altered the expression patterns of seeds storage protein; induced newly synthesized isoforms and disappearance of existing ones. The obtained results using molecular markers confirmed that the lower concentrations of ZnO-NPs (10 and 25 mg/L) are considered as a good enhancement agent, as in case of rice cultivar Sakha101, using UBC 825 primer with 306 bp at concentration of 25 mg/L and OPA-9 primer with 948 bp at concentration of 10 mg/L.

Journal of Plant Protection and Pathology

Archives of Phytopathology and Plant Protection

Journal of Plant Protection and Pathology

The systemic fungicides tricyclazole (Beam 75% WP) and isoprothiolane (Fuji-one 40% EC) are widel... more The systemic fungicides tricyclazole (Beam 75% WP) and isoprothiolane (Fuji-one 40% EC) are widely used to control Pyricularia oryzae infection causing rice blast disease in Egypt. A field experiment was conducted at Rice Research and Training Center farm, Sakha, Kafrelsheikh, Egypt during 2015 and 2016 seasons on susceptible cultivar Sakha 101. The impact of tricyclazole (0.5 mg/L) and isoprothiolane (2 ml/L) on P. oryzae infection, yield and its components, grain quality and chemical components of rice were evaluated. Meanwhile, the fungicides residue dynamics on rice straw, husk and milled rice were determined using Quick Easy Cheap Effective Rugged and Safe (QuEChERS) method combined with HPLC-MS/MS detection after 30 and 60 days post-harvest. The results indicated that tricyclazole and isoprothiolane were significantly possessed a high level of controlling blast disease whereas, both fungicides reduced disease severity, areas under disease progress curve (AUDPC), and rate of leaf blast progress (r-value) disease parameters in both seasons. Residue analysis of tricyclazole in rice straw (1.06 mg/kg) was higher than the residue in the husk and milled rice (0.19 and 0.14 mg/kg, respectively) after 30 days post-harvest. The residues of tricyclazole in the husk and milled rice were lower than the Maximum Residue Limit (MRL). Also, isoprothiolane residue analysis in milled rice was 0.58 mg/kg after 60 days post-harvest and below the MRL. Also, most of the yield and yield components were significantly increased by the application of both fungicides over the untreated plots. Tricyclazole and isoprothiolane treatments enhanced the grain chemical components concentration as carbohydrates, fats, ash, and fiber. Finally, the investigation revealed that tricyclazole and isoprothiolane were effective against rice blast disease and considered safe fungicides according to the European Food Safety Authority. Based on our residue analysis results and Egyptian rice consumption, we suggested that determine our own Egyptian MRL. Whereas, our total rice consumption reaching 4 million ton/year in 2016, it was considered fourth fold than Europe consumption (1 million ton/year).

Archives of Phytopathology and Plant Protection

Egyptian Journal of Biological Pest Control

An efficient biosynthesis process for the rapid production of nanoparticles would enable the deve... more An efficient biosynthesis process for the rapid production of nanoparticles would enable the development of a "microbial nanotechnology" for mass-scale production. In the present research, biological silver nanoparticle was synthesized extracellularly by using the fungus, Trichoderma longibrachiatum, where the cell filtrate of the fungus was used as a reducing and stabilizing agent in the process of nanoparticle synthesis. Different physical parameters such as fungal biomass concentration (1, 5, 10, 15, and 20 g), temperature (25, 28, and 33°C), incubation time (0-120 h) , and agitation (shaken or not shaken) were investigated, in order to determine the optimal conditions for nanoparticle biosynthesis. The stability and antifungal properties of the synthesized silver nanoparticles (AgNPs) were also determined. Data revealed that a combination of 10 g fungal biomass, a reaction temperature of 28°C, a 72-h incubation time, and without shaking were the optimum conditions for the synthesis of the silver nanoparticles. Visual observation of brown color is an indication of silver nanoparticle production. UV-vis spectroscopy showed maximum absorption at 385 nm with the optimum conditions. Transmission electron microscopy (TEM) revealed the formation of monodispersed spherical shape with a mean diameter of 10 nm. Fourier transformation infrared (FTIR) showed bands at1634.92 and 3269. 31 cm −1. Dynamic light scattering (DLS) supported that the Z-average size was 24.43 and 0.420 PdI value. Zeta potential showed − 19.7 mV with a single peak. The AgNPs synthesized through this biosystem approach were relatively stable up to 2 months after synthesis. The use of AgNPs as antifungal led to significant reductions in the number of forming colonies for many plant pathogenic fungi, with efficiencies reaching up to 90% against Fusarium verticillioides, Fusarium moniliforme, Penicillium brevicompactum, Helminthosporium oryzae, and Pyricularia grisea. However, further research should be carried out in order to determine the toxic effect of AgNPs before mass production and use of agricultural applications.

Beni-Suef University Journal of Basic and Applied Sciences

The present study investigates the effect of zinc oxide nanoparticles (ZnO-NPs) on rice plants gr... more The present study investigates the effect of zinc oxide nanoparticles (ZnO-NPs) on rice plants growth and their role in management of brown spot disease caused by the causal agent Helmenthosporium oryza. The antifungal activity of ZnO-NPs (20 to 35 nm particle size) was evaluated at different concentrations. Spores germination percentage, colony formation and sporulation of H. oryza were reduced at concentrations 25 and 50 ppm, in vitro. The greenhouse results showed that seed soaking treatment and foliar spray 5 day before inoculation (DBI) of ZnO-NPs leaded to reduce infection percentage of brown spot without significant difference between ZnO-NPs concentrations. Foliar spray ٢ days post-inoculation (DPI) with the lower concentrations 10 and 25 ppm of ZnO-NPs were able to reduce infection percentage of brown spot. Under field conditions, During 2013 and 2014 seasons at El-sirw Agriculture Research Station, Dammietta, Egypt, rice varieties Giza 177, Giza 178 and Giza 179 under ZnO-NPs level (0, 10, 20 and 30 ppm) as foliar spray twice at mid tillering and panicle initiation stages were evaluated. Application of ZnO-NPs at level 20 ppm effectively reduced brown spot disease severity and discolored grains of all tested varieties. The studied rice varieties were varied in their growth, yield attributes, grain yield and brown spot severity whereas Giza 178 and Giza 179 had good performance under ZnO-NPs treatments. Therefore both Giza 178 and Giza 179 had showed significant salt tolerance at 20 ppm of ZnO-NPs. The performance of Giza 177 as a salinity-sensitive variety was improved at 20 ppm ZnO-NPs. The all ZnO-NPs treatment positively improved rice growth, yield attributes, rice grain yield and brown spot severity over control treatment. Finally, ZnO-NPs can be used as future " nanofertilizers " .

Egyptian Journal of Biological Pest Control, Mar 8, 2018

An efficient biosynthesis process for the rapid production of nanoparticles would enable the deve... more An efficient biosynthesis process for the rapid production of nanoparticles would enable the development of a "microbial nanotechnology" for mass-scale production. In the present research, biological silver nanoparticle was synthesized extracellularly by using the fungus, Trichoderma longibrachiatum, where the cell filtrate of the fungus was used as a reducing and stabilizing agent in the process of nanoparticle synthesis. Different physical parameters such as fungal biomass concentration (1, 5, 10, 15, and 20 g), temperature (25, 28, and 33°C), incubation time (0-120 h) , and agitation (shaken or not shaken) were investigated, in order to determine the optimal conditions for nanoparticle biosynthesis. The stability and antifungal properties of the synthesized silver nanoparticles (AgNPs) were also determined. Data revealed that a combination of 10 g fungal biomass, a reaction temperature of 28°C, a 72-h incubation time, and without shaking were the optimum conditions for the synthesis of the silver nanoparticles. Visual observation of brown color is an indication of silver nanoparticle production. UV-vis spectroscopy showed maximum absorption at 385 nm with the optimum conditions. Transmission electron microscopy (TEM) revealed the formation of monodispersed spherical shape with a mean diameter of 10 nm. Fourier transformation infrared (FTIR) showed bands at1634.92 and 3269. 31 cm −1. Dynamic light scattering (DLS) supported that the Z-average size was 24.43 and 0.420 PdI value. Zeta potential showed − 19.7 mV with a single peak. The AgNPs synthesized through this biosystem approach were relatively stable up to 2 months after synthesis. The use of AgNPs as antifungal led to significant reductions in the number of forming colonies for many plant pathogenic fungi, with efficiencies reaching up to 90% against Fusarium verticillioides, Fusarium moniliforme, Penicillium brevicompactum, Helminthosporium oryzae, and Pyricularia grisea. However, further research should be carried out in order to determine the toxic effect of AgNPs before mass production and use of agricultural applications.

Egyptian Journal of Botany, Jan 8, 2024

Journal of Plant Protection and Pathology, 2010

Rice is the second staple food crop after wheat in Egypt. White tip disease of rice leaves induce... more Rice is the second staple food crop after wheat in Egypt. White tip disease of rice leaves induced by the rice leaf nematode, Aphelenchoides besseyi (Christie, 1942), is widespread nearly in all rice ecosystems all over the world, causing remarkable yield reduction to susceptible cultivars. The losses reach to 47% in Egyptian rice Reiho cultivar. Rice seeds are known as the main source of the disease. The present study was conducted to evaluate the effect of seed priming on white tip nematode infection in rice and seed-borne fungi at different plant growth stages. Severely-infected Reiho rice seeds were primed for 48 hr in solutions of NaCl, CaCl2, Na2CO3, MgSO4, CuSO4 and micronized sulfur, separately or in mixtures of two salts except for the sulfur treatment. The primed seeds and the corresponding control nonprimed counterparts were then rinsed for three times using tap water and incubated at 30 o C to asses the germination percentage, which ranged between 96 to 100% with no significant difference between the primed and non-primed seed treatments. In the lab testing, the maximum seedling vigor index and root / shoot ratio were obtained using seedlings raised from seeds primed with 5 g/L solutions of sulfur (80%WP) followed by sulfur + CaCl2, NaCl and CuSO4. At nursery level, root/shoot ratio increased with all primed seed treatments except with those treated with NaCl solution. Two field experiments were conducted during the 2007and 2008 rice growing seasons. All seed priming treatments significantly enhanced most of the agronomic traits and increased yield in comparison with the non-primed infected or healthy seeds. Soaking in sulfur solution at the concentration of 5g/L and its combinations with the other salts at half dose of each gave the highest mortality of white tip nematode, lowest percentage of white tip infection, and least disease severity. Sulfur and NaCl is then proved to be the most effective priming mixture that can reduce white tip nematode infection. For seedborne fungi, the treatment with CaCl2 alone or in its all combinations has positive effects in elimination of the Fusarium Moniliforme, Helminthosporium oryzae and Alternaria padwickii in comparison with the water treatment control. CaCl2 completely eradiated F. moniliforme. Seed treatment with mixtures of salts reduced the fungal growth more than did one salt alone. Generally, all seeds primed with salts showed lower levels of infection with F. moniliforme comparing with the control. The treatment with CuSO4 solution at 1.5g/L gave complete protection from seed-borne fungi.

Environmental Science and Pollution Research, 2018

Due to the accelerating use of manufactured nanomaterials, more research is needed to define thei... more Due to the accelerating use of manufactured nanomaterials, more research is needed to define their impact on plants. The present investigation aimed at evaluating the effect of different levels (0.0, 10, 25, 50, and 100 mg/L) of ZnO nanoparticles (NPs) on Vicia faba during seed germination and seedling establishment. Additionally, V. faba root meristems were used as a model to monitor the cytotoxic and genotoxic effects resulting from exposure to ZnO NPs. The influence of ZnO NPs on three isoenzyme systems, peroxidase, α, and β esterase, was also evaluated using native-PAGE. Our results showed that lower concentrations of ZnO NPs (especially 10 and 25 mg/L) enhanced seed germination and improved seedling growth, while higher concentrations (100 and 200 mg/L) resulted in phytotoxicity. Cytological investigations of ZnO NPs-treated V. faba root cells denoted the clastogenic and aneugenic nature of ZnO NPs. Differential increase in mitotic index and significant alterations in cell cycle were observed upon exposure to ZnO NPs. High concentrations of ZnO NPs markedly induced chromosomal aberration, micronuclei, and vacuolated nuclei formation. Chromosomal breakage, chromosomal bridges, ring chromosomes, laggard chromosomes, and stickiness were also observed at a higher rate. The PAGE analysis showed that ZnO NPs treatments altered the expression patterns of all studied enzyme systems. Collectively, results from this work will help to further understand the phytotoxic effects of nanomaterials.

Journal of Molecular Modeling, 2016

Histone lysine acetylation is a reversible posttranslational modification that does not involve c... more Histone lysine acetylation is a reversible posttranslational modification that does not involve changes in DNA sequences. Enzymes play an important role in developmental processes and their deregulation has been linked to the progression of diverse disorders. The HAT enzyme family fulfills an important role in various developmental processes mediated by the state of chromatin, and have been attributed to its deregulation. To understand acetylation mechanisms and their role in cell signaling, transcriptional regulation, and apoptosis, it is crucial to identify and analyze acetylation sites. Bioinformatics methods can be used to generate relatively precise predictions. Here we applied classical bioinformatics methods-sequence alignment, homology modeling, and docking-to compare approved and predicted lysine acetylation processes in different organisms. HAM1 and HAM2 are analogs of KAT8 and KAT7 (MYST1 and MYST2), members of the MYST histone acetyltransferase family, and our results show that HAM1 and HAM2 have much in common with other representatives of MYST families from various organisms. One function of acetyl-CoA binding was predicted with a high level of probability by computational methods. Based on our data, we conclude that, despite huge genetic distances and some structural differences between animal and plant species, a closer look at acetylation mechanism shows that they have much in common.

Journal of Plant Protection and Pathology, 2016

The present study investigates the effect of zinc oxide nanoparticles (ZnO-NPs) on rice plants gr... more The present study investigates the effect of zinc oxide nanoparticles (ZnO-NPs) on rice plants growth and their role in management of brown spot disease caused by the causal agent Helmenthosporium oryza. The antifungal activity of ZnO-NPs (20 to 35 nm particle size) was evaluated at different concentrations. Spores germination percentage, colony formation and sporulation of H. oryza were reduced at concentrations 25 and 50 ppm, in vitro. The greenhouse results showed that seed soaking treatment and foliar spray 5 day before inoculation (DBI) of ZnO-NPs leaded to reduce infection percentage of brown spot without significant difference between ZnO-NPs concentrations. Foliar spray ٢ days post-inoculation (DPI) with the lower concentrations 10 and 25 ppm of ZnO-NPs were able to reduce infection percentage of brown spot. Under field conditions, During 2013 and 2014 seasons at El-sirw Agriculture Research Station, Dammietta, Egypt, rice varieties Giza 177, Giza 178 and Giza 179 under ZnO-NPs level (0, 10, 20 and 30 ppm) as foliar spray twice at mid tillering and panicle initiation stages were evaluated. Application of ZnO-NPs at level 20 ppm effectively reduced brown spot disease severity and discolored grains of all tested varieties. The studied rice varieties were varied in their growth, yield attributes, grain yield and brown spot severity whereas Giza 178 and Giza 179 had good performance under ZnO-NPs treatments. Therefore both Giza 178 and Giza 179 had showed significant salt tolerance at 20 ppm of ZnO-NPs. The performance of Giza 177 as a salinity-sensitive variety was improved at 20 ppm ZnO-NPs. The all ZnO-NPs treatment positively improved rice growth, yield attributes, rice grain yield and brown spot severity over control treatment. Finally, ZnO-NPs can be used as future "nanofertilizers".

Journal of Plant Protection and Pathology, 2016

The present study investigates the effect of zinc oxide nanoparticles (ZnO-NPs) on rice plants gr... more The present study investigates the effect of zinc oxide nanoparticles (ZnO-NPs) on rice plants growth and their role in management of brown spot disease caused by the causal agent Helmenthosporium oryza. The antifungal activity of ZnO-NPs (20 to 35 nm particle size) was evaluated at different concentrations. Spores germination percentage, colony formation and sporulation of H. oryza were reduced at concentrations 25 and 50 ppm, in vitro. The greenhouse results showed that seed soaking treatment and foliar spray 5 day before inoculation (DBI) of ZnO-NPs leaded to reduce infection percentage of brown spot without significant difference between ZnO-NPs concentrations. Foliar spray ٢ days post-inoculation (DPI) with the lower concentrations 10 and 25 ppm of ZnO-NPs were able to reduce infection percentage of brown spot. Under field conditions, During 2013 and 2014 seasons at El-sirw Agriculture Research Station, Dammietta, Egypt, rice varieties Giza 177, Giza 178 and Giza 179 under ZnO-NPs level (0, 10, 20 and 30 ppm) as foliar spray twice at mid tillering and panicle initiation stages were evaluated. Application of ZnO-NPs at level 20 ppm effectively reduced brown spot disease severity and discolored grains of all tested varieties. The studied rice varieties were varied in their growth, yield attributes, grain yield and brown spot severity whereas Giza 178 and Giza 179 had good performance under ZnO-NPs treatments. Therefore both Giza 178 and Giza 179 had showed significant salt tolerance at 20 ppm of ZnO-NPs. The performance of Giza 177 as a salinity-sensitive variety was improved at 20 ppm ZnO-NPs. The all ZnO-NPs treatment positively improved rice growth, yield attributes, rice grain yield and brown spot severity over control treatment. Finally, ZnO-NPs can be used as future "nanofertilizers".

This article cites 28 articles, 16 of which can be accessed free

Egyptian Journal of Phytopathology

ice blast caused by Magnaporthe oryzae is the major biotic stress influences rice yield. The curr... more ice blast caused by Magnaporthe oryzae is the major biotic stress influences rice yield. The current investigation aimed to estimate the antifungal activity and phytotoxicity effect of different concentrations of ZnO nanoparticles (0.0, 10, 25, 50, 100 and 200 mg/L) on M. oryzae and rice cultivar Sakha101 using morphological, biochemical and molecular markers. Five ISSR markers and seven RAPD primers were utilized to estimate the potentiality effects of ZnO nanoparticles (NPs). The effect of different rates and applications of ZnO NPs used to control rice blast disease and improve grain yield were estimated in the field during 2017 and 2018 growing seasons. The results showed that, in vitro antifungal assay of ZnO NPs showed a significant decrease in colony formation in comparison to control. Foliar application of ZnO NPs at 25 mg/L was the most effective treatments for mitigation rice blast at five days before inoculation. While under field conditions, foliar spray with 25 mg/L at nursery increased the grain yield to 4.366 ton/fed in season 2017 and to 4.625 ton/fed in 2018. Foliar spray with ZnO NPs of rice offer a practical and useful approach to improve rice grain yield and reduce leaf blast disease when applied at optimal concentrations. ZnO NPs at lower concentrations (10 and 25 mg/L) enhanced seed germination and improved seedling growth, while the higher concentrations (100 and 200 mg/L) resulted in phytotoxicity. ZnO NPs treatments altered the expression patterns of seeds storage protein; induced newly synthesized isoforms and disappearance of existing ones. The obtained results using molecular markers confirmed that the lower concentrations of ZnO-NPs (10 and 25 mg/L) are considered as a good enhancement agent, as in case of rice cultivar Sakha101, using UBC 825 primer with 306 bp at concentration of 25 mg/L and OPA-9 primer with 948 bp at concentration of 10 mg/L.

Journal of Plant Protection and Pathology

Archives of Phytopathology and Plant Protection

Journal of Plant Protection and Pathology

The systemic fungicides tricyclazole (Beam 75% WP) and isoprothiolane (Fuji-one 40% EC) are widel... more The systemic fungicides tricyclazole (Beam 75% WP) and isoprothiolane (Fuji-one 40% EC) are widely used to control Pyricularia oryzae infection causing rice blast disease in Egypt. A field experiment was conducted at Rice Research and Training Center farm, Sakha, Kafrelsheikh, Egypt during 2015 and 2016 seasons on susceptible cultivar Sakha 101. The impact of tricyclazole (0.5 mg/L) and isoprothiolane (2 ml/L) on P. oryzae infection, yield and its components, grain quality and chemical components of rice were evaluated. Meanwhile, the fungicides residue dynamics on rice straw, husk and milled rice were determined using Quick Easy Cheap Effective Rugged and Safe (QuEChERS) method combined with HPLC-MS/MS detection after 30 and 60 days post-harvest. The results indicated that tricyclazole and isoprothiolane were significantly possessed a high level of controlling blast disease whereas, both fungicides reduced disease severity, areas under disease progress curve (AUDPC), and rate of leaf blast progress (r-value) disease parameters in both seasons. Residue analysis of tricyclazole in rice straw (1.06 mg/kg) was higher than the residue in the husk and milled rice (0.19 and 0.14 mg/kg, respectively) after 30 days post-harvest. The residues of tricyclazole in the husk and milled rice were lower than the Maximum Residue Limit (MRL). Also, isoprothiolane residue analysis in milled rice was 0.58 mg/kg after 60 days post-harvest and below the MRL. Also, most of the yield and yield components were significantly increased by the application of both fungicides over the untreated plots. Tricyclazole and isoprothiolane treatments enhanced the grain chemical components concentration as carbohydrates, fats, ash, and fiber. Finally, the investigation revealed that tricyclazole and isoprothiolane were effective against rice blast disease and considered safe fungicides according to the European Food Safety Authority. Based on our residue analysis results and Egyptian rice consumption, we suggested that determine our own Egyptian MRL. Whereas, our total rice consumption reaching 4 million ton/year in 2016, it was considered fourth fold than Europe consumption (1 million ton/year).

Archives of Phytopathology and Plant Protection

Egyptian Journal of Biological Pest Control

An efficient biosynthesis process for the rapid production of nanoparticles would enable the deve... more An efficient biosynthesis process for the rapid production of nanoparticles would enable the development of a "microbial nanotechnology" for mass-scale production. In the present research, biological silver nanoparticle was synthesized extracellularly by using the fungus, Trichoderma longibrachiatum, where the cell filtrate of the fungus was used as a reducing and stabilizing agent in the process of nanoparticle synthesis. Different physical parameters such as fungal biomass concentration (1, 5, 10, 15, and 20 g), temperature (25, 28, and 33°C), incubation time (0-120 h) , and agitation (shaken or not shaken) were investigated, in order to determine the optimal conditions for nanoparticle biosynthesis. The stability and antifungal properties of the synthesized silver nanoparticles (AgNPs) were also determined. Data revealed that a combination of 10 g fungal biomass, a reaction temperature of 28°C, a 72-h incubation time, and without shaking were the optimum conditions for the synthesis of the silver nanoparticles. Visual observation of brown color is an indication of silver nanoparticle production. UV-vis spectroscopy showed maximum absorption at 385 nm with the optimum conditions. Transmission electron microscopy (TEM) revealed the formation of monodispersed spherical shape with a mean diameter of 10 nm. Fourier transformation infrared (FTIR) showed bands at1634.92 and 3269. 31 cm −1. Dynamic light scattering (DLS) supported that the Z-average size was 24.43 and 0.420 PdI value. Zeta potential showed − 19.7 mV with a single peak. The AgNPs synthesized through this biosystem approach were relatively stable up to 2 months after synthesis. The use of AgNPs as antifungal led to significant reductions in the number of forming colonies for many plant pathogenic fungi, with efficiencies reaching up to 90% against Fusarium verticillioides, Fusarium moniliforme, Penicillium brevicompactum, Helminthosporium oryzae, and Pyricularia grisea. However, further research should be carried out in order to determine the toxic effect of AgNPs before mass production and use of agricultural applications.

Beni-Suef University Journal of Basic and Applied Sciences

The present study investigates the effect of zinc oxide nanoparticles (ZnO-NPs) on rice plants gr... more The present study investigates the effect of zinc oxide nanoparticles (ZnO-NPs) on rice plants growth and their role in management of brown spot disease caused by the causal agent Helmenthosporium oryza. The antifungal activity of ZnO-NPs (20 to 35 nm particle size) was evaluated at different concentrations. Spores germination percentage, colony formation and sporulation of H. oryza were reduced at concentrations 25 and 50 ppm, in vitro. The greenhouse results showed that seed soaking treatment and foliar spray 5 day before inoculation (DBI) of ZnO-NPs leaded to reduce infection percentage of brown spot without significant difference between ZnO-NPs concentrations. Foliar spray ٢ days post-inoculation (DPI) with the lower concentrations 10 and 25 ppm of ZnO-NPs were able to reduce infection percentage of brown spot. Under field conditions, During 2013 and 2014 seasons at El-sirw Agriculture Research Station, Dammietta, Egypt, rice varieties Giza 177, Giza 178 and Giza 179 under ZnO-NPs level (0, 10, 20 and 30 ppm) as foliar spray twice at mid tillering and panicle initiation stages were evaluated. Application of ZnO-NPs at level 20 ppm effectively reduced brown spot disease severity and discolored grains of all tested varieties. The studied rice varieties were varied in their growth, yield attributes, grain yield and brown spot severity whereas Giza 178 and Giza 179 had good performance under ZnO-NPs treatments. Therefore both Giza 178 and Giza 179 had showed significant salt tolerance at 20 ppm of ZnO-NPs. The performance of Giza 177 as a salinity-sensitive variety was improved at 20 ppm ZnO-NPs. The all ZnO-NPs treatment positively improved rice growth, yield attributes, rice grain yield and brown spot severity over control treatment. Finally, ZnO-NPs can be used as future " nanofertilizers " .