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Low-stringency single specific primer polymerase chain reaction (LSSP)-PCR was assessed for its suitability in detecting the genotoxic effect of paranitrophenol (PNP) in the dwarf bean (Phaseolus vulgaris) exposed to different concentrations of PNP. DNA was extracted from both PNP-treated and non-treated shoots that was amplified by specific PCR, using universal primers of maturase K chloroplast DNA. PCR products of approximately 776 bp were subsequently used as a template for LSSP-PCR analysis. We detected the genotoxic effect based on LSSP-PCR profiles of the DNA generated in PNP-treated over the non-treated control of bean shoots. A complex electrophoretic pattern consisting of many bands was obtained from control and treated samples. Surprisingly, DNA sequencing data revealed that the homology among the maturase gene amplified from PNP-treated vs. non-treated samples of dwarf beans are comparable. These results showed that the use of LSSP-PCR analysis is not a proper tool to detect genotoxic effect in bean, at least in bean shoots that were exposed to PNP.

Reyes L.H.,Texas A&M University | Abdelaal A.S.,Agricultural Genetic Engineering Research Institute AGERI | Kao K.C.,Texas A&M University
Applied and Environmental Microbiology | Year: 2013

Cross-tolerance and antagonistic pleiotropy have been observed between different complex phenotypes in microbial systems. These relationships between adaptive landscapes are important for the design of industrially relevant strains, which are generally subjected to multiple stressors. In our previous work, we evolved Escherichia coli for enhanced tolerance to the biofuel n-butanol and discovered a molecular mechanism of n-butanol tolerance that also conferred tolerance to the cationic antimicrobial peptide polymyxin B in one specific lineage (green fluorescent protein [GFP] labeled) in the evolved population. In this work, we aim to identify additional mechanisms of n-butanol tolerance in an independent lineage (yellow fluorescent protein [YFP] labeled) from the same evolved population and to further explore potential cross-tolerance and antagonistic pleiotropy between n-butanol tolerance and other industrially relevant stressors. Analysis of the transcriptome data of the YFP-labeled mutants allowed us to discover additional membrane-related and osmotic stress-related genes that confer n-butanol tolerance in E. coli. Interestingly, the n-butanol resistance mechanisms conferred by the membrane-related genes appear to be specific to n-butanol and are in many cases antagonistic with isobutanol and ethanol. Furthermore, the YFP-labeled mutants showed cross-tolerance between n-butanol and osmotic stress, while the GFP-labeled mutants showed antagonistic pleiotropy between n-butanol and osmotic stress tolerance. © 2013, American Society for Microbiology.

Hussein G.M.,Agricultural Genetic Engineering Research Institute AGERI
GM crops & food | Year: 2013

Low transformation efficiency and long generation time for production of transgenic Gerbera jemosonii plants leads to vulnerable gene function studies. Thus, transient expression of genes would be an efficient alternative. In this investigation, a transient expression system for gerbera petals based on the Agrobacterium infiltration protocol was developed using the reporter genes β-glucuronidase (gus) and green florescence protein (gfp). Results revealed the incapability of using the gfp gene as a reporter gene for transient expression study in gerbera flowers due to the detection of green fluorescent color in the non-infiltrated gerbera flower petals. However, the gus reporter gene was successfully utilized for optimizing and obtaining the suitable agroinfiltration system in gerbera flowers. The expression of GUS was detectable after three days of agroinfiltration in gerbera cultivars "Express" and "White Grizzly" with dark pink and white flower colors, respectively. The vacuum agroinfiltration protocol has been applied on the cultivar "Express" for evaluating the transient expression of the two genes involved in the anthocyanin pathway (iris-dfr and petunia-f3' 5'h), which is responsible for the color in flowers. In comparison to the control, transient expression results showed change in the anthocyanin pigment in all infiltrated flowers with color genes. Additionally, blue color was detected in the stigma and pollen grains in the infiltrated flowers. Moreover, blue colors with variant intensities were observed in produced calli during the routine work of stable transformation with f3' 5'h gene.

Mahfouz M.M.,King Abdullah University of Science and Technology | Mahfouz M.M.,Agricultural Genetic Engineering Research Institute AGERI
Plant Signaling and Behavior | Year: 2010

Epigenetic RNA based gene silencing mechanisms play a major role in genome stability and control of gene expression. Transcriptional gene silencing via RNA-directed DNA methylation (RdDM) guides the epigenetic regulation of the genome in response to disease states, growth, developmental and stress signals. RdDM machinery is composed of proteins that produce and modify 24-nt-long sirNAs, recruit the RdDM complex to genomic targets, methylate DNA and remodel chromatin. The final DNA methylation pattern is determined by either DNA methyltransferase alone or by the combined action of DNA methyltransferases and demethylases. The dynamic interaction between RdDM and demethylases may render the plant epigenome plastic to growth, developmental and environmental cues. The epigenome plasticity may allow the plant genome to assume many epigenomes and to have the right epigenome at the right time in response to intracellular or extracellular stimuli. This review discusses recent advances in RdDM research and considers future perspectives. © 2010 Landes Bioscience.

Ashoub A.,Biodiversity and Climate Research Center | Ashoub A.,Agricultural Genetic Engineering Research Institute AGERI | Ashoub A.,Goethe University Frankfurt | Beckhaus T.,Goethe University Frankfurt | And 4 more authors.
Planta | Year: 2013

The adaptive response of Egyptian barley land races to drought stress was analyzed using difference gel electrophoresis (DIGE). Physiological measurements and proteome alterations of accession number 15141, drought tolerant, and accession number 15163, drought sensitive, were compared. Differentially expressed proteins were subjected to MALDI-TOF-MS analysis. Alterations in proteins related to the energy balance and chaperons were the most characteristic features to explain the differences between the drought-tolerant and the drought-sensitive accessions. Further alterations in the levels of proteins involved in metabolism, transcription and protein synthesis are also indicated. © 2012 Springer-Verlag Berlin Heidelberg.

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