Abstract:
Salinity is a major abiotic stress that reduces cro
p productivity in arid and semiarid
soils. About 25% of the country's arable land is af
fected by different levels of salt. A
considerable part of this land is under wheat culti
vation each year as the country's most
important crop. ACC deaminase producing bacteria in
crease plant resistance to stress
condition by reducing stress ethylene in a variety
of environmental stresses such as
salinity. In this study, 167 halotolerant bacterial
strains were isolated from the saline
habitats and screened for growth at different NaCl
concentrations. These
halotolerant
bacterial strains were then tested for 1 AminoCyclo
propane-1-Carboxylic acid (ACC)
deaminase activity. Among six isolates of halotoler
ant bacteria containing ACC
deaminase, the K78 strain produced the highest leve
l of this enzyme. Phylogenetic
analysis of the 16S rRNA gene sequence of this bact
erium indicated that this strain
belonged to
Bacillus mojavensis
. Inoculation of
Bacillus mojavensis
to salt stressed wheat
plants produced an increase in root and shoot weigh
t, chlorophyll content, and nutrient
uptake in comparison with the un-inoculated soils.
In summary, this study indicates that
the use of ACC deaminase-producing halotolerant bac
teria mitigates salinity stress effects
on growth of wheat plants by reducing salt-stress-i
nduced ethylene production.
Keywords
: Abiotic stress,
Bacillus
, Ethylene production, Root growth , Salinity.
