Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) biosynthetic genes ( ect. ABC )... more Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) biosynthetic genes ( ect. ABC ) from Halomonas elongata were introduced to tobacco plants using an Agrobacterium -mediated gene delivery system. The genes for ectoine biosynthesis were integrated in a stable manner into the tobacco genome and the corresponding transcripts were expressed. The concentration of ectoine under saltstress conditions was higher in the roots than in leaves. A close relationship was found between stomatal conductance and the amount of transported nitrogen, suggesting that water transport through the xylem in the stem and transpiration may be involved in nitrogen transport to leaves. The data indicate that the turgor values of the ectoine transgenic lines increased with increasing salt concentration. The data revealed two ways in which ectoine enhanced salinity tolerance of tobacco plants. First, ectoine improved the maintenance of root function so that water is taken up consistently and supplied to shoots under saline conditions. Second, ectoine enhanced the nitrogen supply to leaves by increasing transpiration and by protecting Rubisco proteins from deleterious effects of salt, thereby improving the rate of photosynthesis.
Five bacterial strains were isolated from the hemocoel of the greater wax moth larvae (Galleria m... more Five bacterial strains were isolated from the hemocoel of the greater wax moth larvae (Galleria mel-lonella) infected with the entomopathogenic nematodes:
Two gramineae species, Panicum maximum and Eleusine coracana, were exposed to salinity stress and... more Two gramineae species, Panicum maximum and Eleusine coracana, were exposed to salinity stress and leaf water status, solute concentrations in cell sap, levels of betaine aldehyde dehydrogenase (BADH) and BADH mRNA were measured. Panicum maximum was able to maintain a high turgor and high relative water content at low leaf water potentials, and this was associated with the greater capacity for osmotic adjustment. Major osmotica in Panicum maximum leaves were Na+, Cl-, sugar and glycinebetaine, and these solutes were increased by salinity. Na+ and glycinebetaine concentrations in Eleusine coracana leaves also were increased by salt stress, but these solutes were in significantly lower concentrations than those measured in Panicum maximum. BADH enzyme activity and BADH mRNA levels in Panicum maximum leaves were both increased by salt stress, and their expression coincided with the observed betaine accumulation. Although the addition of abscisic acid (ABA) to leaf disks of Panicum maxim...
Research Journal of Agriculture and Biological Sciences, 2009
... Ahmed M. El-Sharkawy, Sawsan S. Youssef, Reda EA Moghaieb, Eman Sobhy, 1 1 1 2 Rabab G. El Me... more ... Ahmed M. El-Sharkawy, Sawsan S. Youssef, Reda EA Moghaieb, Eman Sobhy, 1 1 1 2 Rabab G. El Mergawy and Etr HK Mohammed 1 1 ... Primer Total scorable band Polymorphic band Polymorphism % Band size range OPE A-10 11 3 27 280-2000 ...
Abs tract: Seven agronomically and genetically different rice (Oryza sativa L.) c u lt iv a rs we... more Abs tract: Seven agronomically and genetically different rice (Oryza sativa L.) c u lt iv a rs were compared for their capacity for callus induction and plant regene ra t io n from mature zygotic embryos . W hite embryonic calli were formed within three weeks in the pres ence of 3 mgl 2,4,D . T h e s o matic -1 e mb ryos directly originated from the embryogenic callus in the presence of 3 mg l BA . The cult iv a r -1 Giza 178 s howed high regeneration fre q u e ncy (39%) followed by Giza 175 (38%) where the cultivar H1 s howed the lowes t record (24%). The data obtained fro m t h e random amplified polymorphic DNA analys is s howed that a total of 45 DNA markers were detected among the s e v e n ric e cultivars of wh ich, 29 bands were polymorphic (64.4%) and can be cons idered as us eful RA PD markers for th e rice cultivars us ed. Based on the data obtained by RA PD analys is , it was pos s ible to dis c riminate between the different genotyp e s u s e d . Sixteen out of the twenty nine polymorphic RAPD markers generated were found to be genotype-specific. Thes e markers can be verified as being RAPD markers ass ociated with the rege n e ra t io n c a pacity in the s even rice genotypes. Genetic s tability in tis s uecultured rice plants was examined by randomly amplified polymorphic DNA (RA PD) an a ly s is . T he genetic s imilarity between the mother and the regenerated plants was hig h fo r Giza 178 (91%) and it w a s 87.5 and 82 for Giza 175 and Sakha 102 respectively. The cultivar Giza 178 proved t o b e a us eful genetic res ource with unique regeneration ability and can be us ed for efficient generation of trans genic rice plants .
Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) biosynthetic genes ( ect. ABC )... more Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) biosynthetic genes ( ect. ABC ) from Halomonas elongata were introduced to tobacco plants using an Agrobacterium -mediated gene delivery system. The genes for ectoine biosynthesis were integrated in a stable manner into the tobacco genome and the corresponding transcripts were expressed. The concentration of ectoine under saltstress conditions was higher in the roots than in leaves. A close relationship was found between stomatal conductance and the amount of transported nitrogen, suggesting that water transport through the xylem in the stem and transpiration may be involved in nitrogen transport to leaves. The data indicate that the turgor values of the ectoine transgenic lines increased with increasing salt concentration. The data revealed two ways in which ectoine enhanced salinity tolerance of tobacco plants. First, ectoine improved the maintenance of root function so that water is taken up consistently and supplied to shoots under saline conditions. Second, ectoine enhanced the nitrogen supply to leaves by increasing transpiration and by protecting Rubisco proteins from deleterious effects of salt, thereby improving the rate of photosynthesis.
In order to investigate the influence of genetic makeup on salt tolerance in wheat, seedlings of ... more In order to investigate the influence of genetic makeup on salt tolerance in wheat, seedlings of seven T. aestivum and two T. durum cultivars were subjected to salt stress for two weeks. Leaf osmotic adjustment, total sugars, free amino acids and proline under salt stress were studied. The concentration of total sugars, total free amino acids and free proline were increased by salinity. Salt stress decreased leaf osmotic potential in all cultivars. The difference in osmotic adjustment between the cultivars was correlated with the concentrations of minerals examined such as Na+ and K+. The salt tolerance in the T. aestivum cultivar Gemmeiza 10, and in T. durum cultivars Sohag and Beni Sweif is due to higher ability to maintain osmotic potential of the cells than the other cultivars by increases in osmoticum concentration under salt stress. The cultivars Gemmeiza10, Sohag and Beni Sweif showed higher peroxidase band intensity under salinity stress compared with the other cultivars use...
The objective of the present investigation is to develop an efficient method for shoot and plant ... more The objective of the present investigation is to develop an efficient method for shoot and plant regeneration using five commercial Egyptian clover (Trifolium alexandrinum) cultivars grown under the Egyptian agricultural conditions. The regeneration efficiency from hypocotyls and petiole explants was examined. The data indicated that embryonic calli were formed within one week in the presence of 1.5 mgl -1 2,4-D. Adventitious shoots emerged from the embryonic callus in the presence of 1.5 mgl -1 BA. The petiole explants show higher callus and shoot induction percentages compared with the hypocotyls in all cultivars tested. The cultivars showed a varied response to shoot regeneration. Regeneration frequency was high in the cultivar Serw 1 follwed by Helaly 22 and 19% respectively compared with the other cultivars tested. Petiole explants from the cultivars Serw 1 and Helaly were inoculated and co-cultivated with Agrobacterium tumefaciens strain LBA4404 harboring a binary vector pBI-121 containing the βglucurodinase (gus) gene under the genetic control of CaMV-35S promoter and nopalinsynthase terminator. The resulted putative transgenic plantlets were able to grow under knanamycin containing medium. The stable integration of the gus gene into the plant genomes was confirmed by dot blot and by PCR analysis using 35 S promoter specific primers. The transformation percentage of the clover cultivars Serw 1 and Helaly was 56.2 and 28 % respectively. The gus gene expression can be detected only in the transgenic plants. The developed protocol for regeneration of transgenic plants in the present study is repeatable and can be used to regenerate transgenic clover plants expressing the genes present in A. tumifaciens binary vectors.
Ectoine is a common compatible solute in halophilic bacteria. Its biosynthesis originates from L-... more Ectoine is a common compatible solute in halophilic bacteria. Its biosynthesis originates from L-aspartate β-semialdehyde and requires three enzymes: L-2, 4-diaminobutyric acid aminotransferase (gene: ect B), L-2,4-diaminobutyric acid acetyl transferase (gene: ect A) and L-ectoine synthase (gene: ect C). Genetically engineered tomato plants expressing the three H. elongata genes (ectA, ectB, and ectC) generated showed no phenotypic abnormality. Expression of the ectoine biosynthetic genes was detected in the T3 transgenic plants by Northern blot analysis. The ectoine accumulating T3 plants were evaluated for salt tolerance by examining their photosynthestic activity, osmotic adjustment and carbon partitioning. Nuclear magnetic resonance (NMR) detected the accumulation of ectoine. The concentration of ectoine increased with increasing salinity. The transgenic lines showed higher activities of peroxidase, while the malondialdehyde (MDA) concentration was decreased under salinity stres...
To study the influence of genetic background on the transformation and regeneration of cultivated... more To study the influence of genetic background on the transformation and regeneration of cultivated tomato plants, hairy root lines of tomato (Lycopersicon esculentum) were obtained by inoculating the hypocotyl explants of three tomato cultivars with the Agrobacterium rhizogenes strain DCAR-2, which harbors the pBI-121 binary vector. The Ri-T-DNA transformation into the plant DNA was confirmed by both of mikimopine and GUS assay analyses. The regeneration efficiency from hairy root explants was assessed. The data indicated that white embryonic calli were formed within two weeks in the presence of 2 mgl(-1) 2, 4-D plus 0.25 mgl(-1) kinetin. Adventitious shoots emerged from the embryonic callus in the presence of 1 mgl(-1) GA3 along with 0.5 mgl(-1) NAA. The regeneration frequency was higher in the cultivar UC-97, followed by Momotaro and then Edkawi. Molecular confirmation of the integration of the GUS gene into the hairy root-derived plants genomes was done via PCR using GUS-specific ...
The objective of the present investigation is to develop an efficient method for shoot and plant ... more The objective of the present investigation is to develop an efficient method for shoot and plant regeneration using five commercial Egyptian clover (Trifolium alexandrinum) cultivars grown under the Egyptian agricultural conditions. The regeneration efficiency from hypocotyls and petiole explants was examined. The data indicated that embryonic calli were formed within one week in the presence of 1.5 mgl -1 2,4-D. Adventitious shoots emerged from the embryonic callus in the presence of 1.5 mgl -1 BA. The petiole explants show higher callus and shoot induction percentages compared with the hypocotyls in all cultivars tested. The cultivars showed a varied response to shoot regeneration. Regeneration frequency was high in the cultivar Serw 1 follwed by Helaly 22 and 19% respectively compared with the other cultivars tested. Petiole explants from the cultivars Serw 1 and Helaly were inoculated and co-cultivated with Agrobacterium tumefaciens strain LBA4404 harboring a binary vector pBI-121 containing the βglucurodinase (gus) gene under the genetic control of CaMV-35S promoter and nopalinsynthase terminator. The resulted putative transgenic plantlets were able to grow under knanamycin containing medium. The stable integration of the gus gene into the plant genomes was confirmed by dot blot and by PCR analysis using 35 S promoter specific primers. The transformation percentage of the clover cultivars Serw 1 and Helaly was 56.2 and 28 % respectively. The gus gene expression can be detected only in the transgenic plants. The developed protocol for regeneration of transgenic plants in the present study is repeatable and can be used to regenerate transgenic clover plants expressing the genes present in A. tumifaciens binary vectors.
Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) biosynthetic genes ( ect. ABC )... more Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) biosynthetic genes ( ect. ABC ) from Halomonas elongata were introduced to tobacco plants using an Agrobacterium -mediated gene delivery system. The genes for ectoine biosynthesis were integrated in a stable manner into the tobacco genome and the corresponding transcripts were expressed. The concentration of ectoine under saltstress conditions was higher in the roots than in leaves. A close relationship was found between stomatal conductance and the amount of transported nitrogen, suggesting that water transport through the xylem in the stem and transpiration may be involved in nitrogen transport to leaves. The data indicate that the turgor values of the ectoine transgenic lines increased with increasing salt concentration. The data revealed two ways in which ectoine enhanced salinity tolerance of tobacco plants. First, ectoine improved the maintenance of root function so that water is taken up consistently and supplied to shoots under saline conditions. Second, ectoine enhanced the nitrogen supply to leaves by increasing transpiration and by protecting Rubisco proteins from deleterious effects of salt, thereby improving the rate of photosynthesis.
Five bacterial strains were isolated from the hemocoel of the greater wax moth larvae (Galleria m... more Five bacterial strains were isolated from the hemocoel of the greater wax moth larvae (Galleria mel-lonella) infected with the entomopathogenic nematodes:
Two gramineae species, Panicum maximum and Eleusine coracana, were exposed to salinity stress and... more Two gramineae species, Panicum maximum and Eleusine coracana, were exposed to salinity stress and leaf water status, solute concentrations in cell sap, levels of betaine aldehyde dehydrogenase (BADH) and BADH mRNA were measured. Panicum maximum was able to maintain a high turgor and high relative water content at low leaf water potentials, and this was associated with the greater capacity for osmotic adjustment. Major osmotica in Panicum maximum leaves were Na+, Cl-, sugar and glycinebetaine, and these solutes were increased by salinity. Na+ and glycinebetaine concentrations in Eleusine coracana leaves also were increased by salt stress, but these solutes were in significantly lower concentrations than those measured in Panicum maximum. BADH enzyme activity and BADH mRNA levels in Panicum maximum leaves were both increased by salt stress, and their expression coincided with the observed betaine accumulation. Although the addition of abscisic acid (ABA) to leaf disks of Panicum maxim...
Research Journal of Agriculture and Biological Sciences, 2009
... Ahmed M. El-Sharkawy, Sawsan S. Youssef, Reda EA Moghaieb, Eman Sobhy, 1 1 1 2 Rabab G. El Me... more ... Ahmed M. El-Sharkawy, Sawsan S. Youssef, Reda EA Moghaieb, Eman Sobhy, 1 1 1 2 Rabab G. El Mergawy and Etr HK Mohammed 1 1 ... Primer Total scorable band Polymorphic band Polymorphism % Band size range OPE A-10 11 3 27 280-2000 ...
Abs tract: Seven agronomically and genetically different rice (Oryza sativa L.) c u lt iv a rs we... more Abs tract: Seven agronomically and genetically different rice (Oryza sativa L.) c u lt iv a rs were compared for their capacity for callus induction and plant regene ra t io n from mature zygotic embryos . W hite embryonic calli were formed within three weeks in the pres ence of 3 mgl 2,4,D . T h e s o matic -1 e mb ryos directly originated from the embryogenic callus in the presence of 3 mg l BA . The cult iv a r -1 Giza 178 s howed high regeneration fre q u e ncy (39%) followed by Giza 175 (38%) where the cultivar H1 s howed the lowes t record (24%). The data obtained fro m t h e random amplified polymorphic DNA analys is s howed that a total of 45 DNA markers were detected among the s e v e n ric e cultivars of wh ich, 29 bands were polymorphic (64.4%) and can be cons idered as us eful RA PD markers for th e rice cultivars us ed. Based on the data obtained by RA PD analys is , it was pos s ible to dis c riminate between the different genotyp e s u s e d . Sixteen out of the twenty nine polymorphic RAPD markers generated were found to be genotype-specific. Thes e markers can be verified as being RAPD markers ass ociated with the rege n e ra t io n c a pacity in the s even rice genotypes. Genetic s tability in tis s uecultured rice plants was examined by randomly amplified polymorphic DNA (RA PD) an a ly s is . T he genetic s imilarity between the mother and the regenerated plants was hig h fo r Giza 178 (91%) and it w a s 87.5 and 82 for Giza 175 and Sakha 102 respectively. The cultivar Giza 178 proved t o b e a us eful genetic res ource with unique regeneration ability and can be us ed for efficient generation of trans genic rice plants .
Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) biosynthetic genes ( ect. ABC )... more Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) biosynthetic genes ( ect. ABC ) from Halomonas elongata were introduced to tobacco plants using an Agrobacterium -mediated gene delivery system. The genes for ectoine biosynthesis were integrated in a stable manner into the tobacco genome and the corresponding transcripts were expressed. The concentration of ectoine under saltstress conditions was higher in the roots than in leaves. A close relationship was found between stomatal conductance and the amount of transported nitrogen, suggesting that water transport through the xylem in the stem and transpiration may be involved in nitrogen transport to leaves. The data indicate that the turgor values of the ectoine transgenic lines increased with increasing salt concentration. The data revealed two ways in which ectoine enhanced salinity tolerance of tobacco plants. First, ectoine improved the maintenance of root function so that water is taken up consistently and supplied to shoots under saline conditions. Second, ectoine enhanced the nitrogen supply to leaves by increasing transpiration and by protecting Rubisco proteins from deleterious effects of salt, thereby improving the rate of photosynthesis.
In order to investigate the influence of genetic makeup on salt tolerance in wheat, seedlings of ... more In order to investigate the influence of genetic makeup on salt tolerance in wheat, seedlings of seven T. aestivum and two T. durum cultivars were subjected to salt stress for two weeks. Leaf osmotic adjustment, total sugars, free amino acids and proline under salt stress were studied. The concentration of total sugars, total free amino acids and free proline were increased by salinity. Salt stress decreased leaf osmotic potential in all cultivars. The difference in osmotic adjustment between the cultivars was correlated with the concentrations of minerals examined such as Na+ and K+. The salt tolerance in the T. aestivum cultivar Gemmeiza 10, and in T. durum cultivars Sohag and Beni Sweif is due to higher ability to maintain osmotic potential of the cells than the other cultivars by increases in osmoticum concentration under salt stress. The cultivars Gemmeiza10, Sohag and Beni Sweif showed higher peroxidase band intensity under salinity stress compared with the other cultivars use...
The objective of the present investigation is to develop an efficient method for shoot and plant ... more The objective of the present investigation is to develop an efficient method for shoot and plant regeneration using five commercial Egyptian clover (Trifolium alexandrinum) cultivars grown under the Egyptian agricultural conditions. The regeneration efficiency from hypocotyls and petiole explants was examined. The data indicated that embryonic calli were formed within one week in the presence of 1.5 mgl -1 2,4-D. Adventitious shoots emerged from the embryonic callus in the presence of 1.5 mgl -1 BA. The petiole explants show higher callus and shoot induction percentages compared with the hypocotyls in all cultivars tested. The cultivars showed a varied response to shoot regeneration. Regeneration frequency was high in the cultivar Serw 1 follwed by Helaly 22 and 19% respectively compared with the other cultivars tested. Petiole explants from the cultivars Serw 1 and Helaly were inoculated and co-cultivated with Agrobacterium tumefaciens strain LBA4404 harboring a binary vector pBI-121 containing the βglucurodinase (gus) gene under the genetic control of CaMV-35S promoter and nopalinsynthase terminator. The resulted putative transgenic plantlets were able to grow under knanamycin containing medium. The stable integration of the gus gene into the plant genomes was confirmed by dot blot and by PCR analysis using 35 S promoter specific primers. The transformation percentage of the clover cultivars Serw 1 and Helaly was 56.2 and 28 % respectively. The gus gene expression can be detected only in the transgenic plants. The developed protocol for regeneration of transgenic plants in the present study is repeatable and can be used to regenerate transgenic clover plants expressing the genes present in A. tumifaciens binary vectors.
Ectoine is a common compatible solute in halophilic bacteria. Its biosynthesis originates from L-... more Ectoine is a common compatible solute in halophilic bacteria. Its biosynthesis originates from L-aspartate β-semialdehyde and requires three enzymes: L-2, 4-diaminobutyric acid aminotransferase (gene: ect B), L-2,4-diaminobutyric acid acetyl transferase (gene: ect A) and L-ectoine synthase (gene: ect C). Genetically engineered tomato plants expressing the three H. elongata genes (ectA, ectB, and ectC) generated showed no phenotypic abnormality. Expression of the ectoine biosynthetic genes was detected in the T3 transgenic plants by Northern blot analysis. The ectoine accumulating T3 plants were evaluated for salt tolerance by examining their photosynthestic activity, osmotic adjustment and carbon partitioning. Nuclear magnetic resonance (NMR) detected the accumulation of ectoine. The concentration of ectoine increased with increasing salinity. The transgenic lines showed higher activities of peroxidase, while the malondialdehyde (MDA) concentration was decreased under salinity stres...
To study the influence of genetic background on the transformation and regeneration of cultivated... more To study the influence of genetic background on the transformation and regeneration of cultivated tomato plants, hairy root lines of tomato (Lycopersicon esculentum) were obtained by inoculating the hypocotyl explants of three tomato cultivars with the Agrobacterium rhizogenes strain DCAR-2, which harbors the pBI-121 binary vector. The Ri-T-DNA transformation into the plant DNA was confirmed by both of mikimopine and GUS assay analyses. The regeneration efficiency from hairy root explants was assessed. The data indicated that white embryonic calli were formed within two weeks in the presence of 2 mgl(-1) 2, 4-D plus 0.25 mgl(-1) kinetin. Adventitious shoots emerged from the embryonic callus in the presence of 1 mgl(-1) GA3 along with 0.5 mgl(-1) NAA. The regeneration frequency was higher in the cultivar UC-97, followed by Momotaro and then Edkawi. Molecular confirmation of the integration of the GUS gene into the hairy root-derived plants genomes was done via PCR using GUS-specific ...
The objective of the present investigation is to develop an efficient method for shoot and plant ... more The objective of the present investigation is to develop an efficient method for shoot and plant regeneration using five commercial Egyptian clover (Trifolium alexandrinum) cultivars grown under the Egyptian agricultural conditions. The regeneration efficiency from hypocotyls and petiole explants was examined. The data indicated that embryonic calli were formed within one week in the presence of 1.5 mgl -1 2,4-D. Adventitious shoots emerged from the embryonic callus in the presence of 1.5 mgl -1 BA. The petiole explants show higher callus and shoot induction percentages compared with the hypocotyls in all cultivars tested. The cultivars showed a varied response to shoot regeneration. Regeneration frequency was high in the cultivar Serw 1 follwed by Helaly 22 and 19% respectively compared with the other cultivars tested. Petiole explants from the cultivars Serw 1 and Helaly were inoculated and co-cultivated with Agrobacterium tumefaciens strain LBA4404 harboring a binary vector pBI-121 containing the βglucurodinase (gus) gene under the genetic control of CaMV-35S promoter and nopalinsynthase terminator. The resulted putative transgenic plantlets were able to grow under knanamycin containing medium. The stable integration of the gus gene into the plant genomes was confirmed by dot blot and by PCR analysis using 35 S promoter specific primers. The transformation percentage of the clover cultivars Serw 1 and Helaly was 56.2 and 28 % respectively. The gus gene expression can be detected only in the transgenic plants. The developed protocol for regeneration of transgenic plants in the present study is repeatable and can be used to regenerate transgenic clover plants expressing the genes present in A. tumifaciens binary vectors.
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