الفهرس 
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Abstract
Due to their wide use as biological control agents because they contain antibiotic
resistance and some enzymes that enable them to withstand in the soil and resist plant
pathogens, the choice was for the Pseudomonas bacteria to be the focus of the research, so
we used them as effective biological control agents in the face of a fierce parasite that
threatens life. The plant causes losses of millions of tons annually in economic crops, which
are nematodes, especially the root-knot nematode, which is called Meloidogyne. where we
studied the genetic identification of these types of bacteria resistant to nematodes as well
as nematodes, all through some of the genetic identification genes of these organisms. We
also studied some of the characteristics of genes affected by Pseudomonas bacteria inside
nematode cells, which led to their death and the end of their danger, as the content of the
research was in two points as follows:
First: Identification
Through the polymerase chain reaction (PCR) using primers such as 16S for bacteria and
SCAR for nematodes, we were able to define the bacteria and nematodes genetically, as
we confirmed with similarity rates exceeding 90% by comparing them on GenBank that
the types of bacteria were (Pseudomonas Fluorescens, Pseudomonas Putida) and the
parasitic nematode type of root-knot nematode It was Meloidogene incognita. Also, using
the ITS primer, we identified some types of fungi surrounding the roots that are affected
and affected by nematodes and their metabolism, and among them was a nematodetrappimg fungus called (Monacrosporium drechsleri).
Second: characterization of some nematode genes
To obtain some genes that were affected by infection with bacteria inside nematode cells,
it was necessary to extract the mRNA of those genes, and in order to do that, the first
experiment was the Bioassay, where we treated nematodes with two types of bacteria for
five known times, which were as follows (6 hours, 12 hours, and 24 hours And 3 days and
7 days) Then, we proceeded directly to the extraction of mRNA from those samples by
extracting the RNA and converting it into cDNA by some of the chemicals that were
mentioned in the research.
After we extracted the cDNA from nematode cells in the presence of bacteria, we used
DD-PCR to note the genes that we succeeded in extracting and the density of each gene
using gel electrophoresis.
Then we used the RT-PCR reaction to find out the extent of gene expression for each gene
separately and how those genes in the nematode were affected by the biological resistance
of Pseudomonas bacteria.
All the genes used were negatively affected by the bacteria, as their gene expression
decreased, which led to disturbances and death within the nematode cells. Those genes
used were as follows:
Summary
82
MIGA gene, which is the gene responsible for the formation of the mitochondrial wall
inside the nematode cells, and when its gene expression decreased, this caused the
deterioration of the mitochondria and caused the death of the nematode.
APX gene is responsible for the production of the Ascorbate Peroxidase enzyme, and its
function is to give cells the ability to absorb oxygen from the soil and convert H2o2 into
H2o and O2, which facilitates the breathing process for nematodes because they are aerobic
organisms, that is, they need oxygen to breathe and carry out their vital processes, and any
effect by it causes direct death of the nematode .
P27 gene is responsible for the production of the prion protein, and this protein is primarily
responsible for the formation of parts of the neurons in the brain. The effect of bacteria on
this gene was a major cause of the death of nematodes and their slow movement over time
under the microscope.
CYP 82 gene, which is part of the cytochrome group, is responsible for the production of
antibiotic sensitivity genes and gives the organism the ability to resist bacteria that affect
its immune system.
Previously, it was found that at the genetic level, Pseudomonas bacteria were very effective
as biological control agents in eliminating the Meloidogyne root-knot nematode, and
directly affected some of the genes essential to the life of these nematodes, and any
violation of them affects them and causes their death.