الفهرس 
Material and methodsOnly 14 pages are availabe for public view
Abstract
Summary
This work is an attempet to produce plants can resist salt stress and also
drought stress, two screening strategies can be applied using T- DNA mutants
from Arabidopsis ecotype Wassilevskija using the binary vector pGKB5 which
possesses the reporter GUS promoterless gene from Versailles lines INRA.
Screening for. 44 pools of 100 with two strategies permitted obtaining of
Arabidopsis putative mutants can resist high salt concentration (300 111M: NaCl) .
• The first strategy (loss -of - function screening) :-
This strategy depending on isolating mutants, their genomes, were interrupted
by the GUS promoterless gene that resulting in loosing the function of these
genes (susceptibility to salt stress). 44 pools of 100 from Versailles lines were
screened with selection system for salt resistance in addition to the pools of 20
and their individuals which gave positive results. We set up this screening with
wild type and the chosed lethal concentration was 300 mM which kills the
seedlings of wild type completely after ~ 15 days. The survival seedlings which
can grow and exhibited vigorus growth after the death of the wild type as a
control are considered survivals (putative mutants).
Two mutant lines were obtained through this screening from pools of 20
(N5308-1 and N5308-2), two Kan. mutants resistant, germinated on Kan.
(50pg/ml) with the ratio 3-1, it means that these mutants have one copy of
integrated T - DNA .So through screening of 44 pools of 100, and pools of20
which belong to 15 pools of 100 gave positive results, we could isolate two
mutant lines that can resist salinty / drought stress.
These mutants have one copy of the T-DNA integrated, so one copy of the
gene facilitates its isolation and using it to transform plants susceptible to salt
and drought stress to be resistant .
• The Second Strategy (Gene -Activation Screening):-
This strategy aimed to get genes which had been activated or stimulated by
salt _ ~tre_~s(300rnM NaCI). We used GUS assay of (Jefferson, 1987) with
modifications in the initial conditions of this assayUsing Lti 78 gus mutants we
concluded that vacuum infiltration and incubation at 37”C over night are not
necessary to be used any more. In this strategy we screened 44 pools of 100, 27
pools of them gave positive results as different blue parts with different staining
intensities.
Pools of 20 of these 27 pools of 100 were screened in the same way in two
individual experiments using a control (without induction) to eleminate
constitutive genes. The results of the pools of 20 were classified into four
categories as follows :-
t” category :
2 individual experiments are okay: the control doesn’t show positive results
or the numbers of the control are less (to a significant degree) than the induced,
and fits the result of pool of 100, such as N5356, N5541 and N5566.
2nd category :
The 2 individual experiments are okay and fit the pool of 100 partially, such
as N53S4 and NS581.
3rd category :
One of the 2 individual experiments is okay and fits pool of 100 , the second
experiment is not okay. Such as N5563 , N5578 , N5532, N5374, N5376 and
N5380.
4th category :
One of the 2 individual experiments_fits pool of 100 partially while the other
is zero - such as N5533 , N5548 , N5511, N5302 and N5480.
So, we chosed the next pools of20 to screen their individuals N5356, N5541,
N5566, N5354, N5581, N5563, N5578, N5532, N5533, N5548 and N5511.
The individuals of these 11 pools of 20 were also screened.
So we got individuals which may have gene (s) resistant for salt stress and
some of them may be activated not only by salt stress but also by heat.
This gives a variable putative mutants resist salinity / drought stress, from
which different genes could be isolated and using them to transform other plants
to be tolerant to salinity / drought stress.