Biology Reference
In-Depth Information
Drought constitutes another form of water stress that results
from shortage of water. Unlike fl ooding, drought induces osmotic
stress, which affects plants metabolisms and yield. Mohammadi
et al. [
31
] have recently investigated the response of 3-day-old soy-
bean seedlings to drought and polyethylene glycol (PEG)-induced
osmotic stress. Proteomic study revealed that root was the most
drought-responsive organ as evident from 32, 13, and 12 proteins
with altered expressions in response to drought stress, PEG treat-
ment, and both, respectively. Expressions of metabolism-related
proteins were shown to be increased in leaves of both PEG-treated
and drought-stressed seedlings, while proteins related to energy
production- and protein synthesis were decreased. In contrast to
waterlogging stress, increased APX abundance was evident in
drought stressed soybeans. Down regulation of methionine syn-
thase both at mRNA and protein levels of drought-stressed plants
irrespective of organs indicates its possible role in impairment of
seedling growth under drought condition.
Soil salinity is considered as one of the environmental constrains
that limits productivity of crop plants including legumes. To eluci-
date the response of soybean to salt stress, the related changes in
protein expressions were investigated using proteomic approach
[
32
]. Proteins from the hypocotyls and roots of 100 mM NaCl
treated soybean were extracted and separated by 2-DE. MS analysis
revealed increase of late embryogenesis-abundant protein,
β
-conglycinin, elicitor peptide three precursors, and basic/helix-
loop-helix protein, while protease inhibitor, lectin, and stem 31-kDa
glycoprotein precursor were decreased. Expressions of metabolism
related proteins are mostly affected by salt stress. Sobhanian et al.
[
33
] reported signifi cant decrease of glyceraldehyde-3-phosphate
dehydrogenase and fructokinase 2 in hypocotyls of 1-week-old soy-
bean seedlings exposed to 40 mM NaCl treatment. Low expression
of glyceraldehyde-3-phosphate dehydrogenase at both protein and
mRNA levels coupled with decreased plant growth indicates that
metabolism of glucose through glycolysis is important to meet the
required energy to overcome the salinity stress.
Contamination of agricultural soil by heavy metals has become
a global concern. High accumulation of toxic metals signifi cantly
affects soybean growth and development. Soybean cultivars
although differ in their ability to uptake, accumulation and trans-
location of cadmium to aerial part, little attention has been paid so
far to unravel the underlying molecular mechanism of cadmium
tolerance. Ahsan et al. [
34
] investigated differential responses of
root microsomal proteins in contrasting cadmium accumulating
soybean cultivars exposed to 100
M of CdCl
2
. Combined pro-
teomic and metabolomics analyses reveal that proteins and amino
acids associated with cadmium chelating pathways are highly active
in low root-to-shoot cadmium translocating cultivar. In addition,
proteins involved in lignin biosynthesis were shown to be increased
μ
