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Ongoing Research

Microbial typing is most accurately determined by genomic fingerprinting methods. Several methodologies are commonly employed, including pulsed-field electrophoresis, ribotyping, restriction endonuclease analysis, multilocus enzyme electrophoresis, and PCR-based procedures. Molecular markers methods can be utilized to determine variations in DNA sequences among closely related species, thus allowing subtype differentiation.

DNA-based Technologies. Deoxyribonucleic acid (DNA) is our hereditary, or genetic, material. DNA is contained inside each individual cell of all plants and animals, including humans. Each cell of an individual, whether a plant or an animal, contains an identical copy of that individual's DNA. All DNA is constructed from the same four building blocks, called bases; it is only the arrangement, or sequence, of the building blocks that differs between.Scientists first discovered the structure of DNA back in the 1950s. Subsequent breakthroughs in technology have enabled scientists to remove the DNA from a cell and reproduce it in a test tube. Together, these discoveries have led to an increasing amount of research focussing in at the DNA-level to identify the similarities and differences between species and occasionally, and more contentiously, to modify the genetic material of an individual by introducing a piece of DNA from a different individual into its cell.

At the MML, DNA-based technologies are used to support:

1-Genetic Diversity Studies.An understanding of the genetic diversity in a plant population, or the genetic diversity of a pathogen or pest, is a necessary first step to understanding a disease or pest problem. Many pathogens have more than one form, called a 'race', similar to the genetic diversity of the human race. Not all races of the one pathogen may cause disease, and/or their pathogenicity may be specific to a species of plant, or to a specific cultivar, or breed, of a plant species. Similarly, some plants may have a naturally higher tolerance to attack from a specific pathogen or pest, or may be totally resistant to a disease. It is now possible to detect these differences at the DNA level.Clearly, the disease-plant interaction can be quite complex, and DNA technology can help us unravel this complexity.

Research projects about genetic diversity at the MML:

1-Genetic diversity and molecular phylogeny of Fusarium spp. isolated from Egyptian cotton cultivars.

2-Molecular phylogeny of Rhizoctonia solani AGs using AFLP, PCR-RFLP techniques.

3-Genetic diversity and vegetative compatibility among Trichoderma spp. isolates.

2-DNA-based Diagnostics. Sensitive detection as well as knowledge of the genetic variability of pest/host populations form essential parts of any integrated pest/disease management strategy. The Molecular Diagnostics Group develops nucleic acid-based diagnostic tools for sensitive detection and discrimination of plant pathogens and their vectors. In addition, molecular marker methods are being employed to identify host resistance genes.The Molecular Diagnostics Group carries out strategic and applied nucleic-acid based research to provide tools for the detection of pathogens or pests, and to allow epidemiological questions to be answered.

Research projects about DNA-based Diagnostics at the MML:

1-Development of DNA- or RNA-based methods for pathogen diagnosis.

2-DNA diagnostics technology for Fusarium wilt of cotton in Egypt.

3-Routine DNA based diagnostic tests for Phytophthora infestans.

4-Development of sensitive PCR-based tests to detect and differentiate sub-groups of Ralstonia solanacearum, causal agent of bacterial wilt.

3-Gene Discovery. Genes are the pieces of DNA that actually carry the information for specific functions. Sequencing all of the genetic material of plants and animals may be useful for generally identifying areas that are the same or different between them, but it is still necessary to locate the genes that are buried within the sequence to be able to determine which specific parts of the genetic information are involved in various functions, for example providing disease resistance.

Research projects about gene discovery at the MML:

1-Cloning yellow rust resistance genes from wheat.

4- Molecular epidemiology. Detection of certain markers in these genomes can highlight the presence of genetic variability between pathogenic agents of the same population previously assumed to be uniform-the population can thus be divided into subgroups. The evolution of each subgroup can be monitored to study the dynamics of pathogen populations. This qualitative approach, now called "molecular epidemiology", has revolutionized the work of epidemiologists. Some markers, associated with biological functions, are of particular interest. In epidemiology, for example, it is important to distinguish between individuals on the basis of their pathogenicity or origin.

Research projects about molecular epidemiology at the MML:

1- Genetic mapping of virulence gene in wheat rusts.

5- Bioinformatics.

1-Training and formal teaching on molecular diagnostic methods, including (RT)-PCR, RAPD and AFLP fingerprinting.