Biology Reference
In-Depth Information
lignin staining confi rmed suppression of lignifi cation in the roots of
fl ooding stressed soybeans. Results suggested that the suppression
of cell wall lignifi cation was caused by down regulation of jasmo-
nate biosynthesis following fl ooding stress.
Plasma membrane acts as the communication interface between
the cellular cytoplasm and the extracellular environment. It has
been a subject of interest of many proteomic researchers as pro-
cessing of biotic and abiotic stress signals primarily occur in the
plasma membrane. Komatsu et al. [
40
] explored the effects of
fl ooding stress on soybean plasma membrane proteins using an
aqueous two-phase partitioning method. 2-DE MS/protein
sequencer-based proteomics and nanoLC-MS/MS-based pro-
teomic techniques were compared to identify the fl ooding stress
responsive proteins. Higher abundance of cell wall proteins in the
plasma membrane of fl ooded plants suggests the contribution of
plasma membrane in constructing cell wall. In addition, increased
expression of superoxide dismutase indicates that the antioxidative
system play a crucial role in protecting cells from oxidative stress
damage following exposure to fl ooding stress. Moreover, heat
shock cognate 70 kDa protein likely play a signifi cant role in pro-
tecting other proteins from denaturation and degradation during
fl ooding stress. Authors suggest that signaling proteins, such as
14-3-3 and serine/threonine protein kinase and band 7 family
proteins, might work cooperatively to regulate plasma membrane
H
+
-ATPase and thus maintain ion homeostasis.
Nouri and Komatsu [
41
] compared both gel-based and LC
MS/MS-based proteomic techniques to study the PEG mediated
osmotic stress induced changes in soybean plasma membrane pro-
teome. Interestingly, LC MS/MS-based method was found to be
more effective in identifying most of the transporter proteins and
proteins with high number of transmembrane helices as well as low-
abundance proteins. Using the gel-based proteomics, four and eight
protein spots were identifi ed as increased and decreased, respectively,
while in the nanoLC MS/MS approach, 11 and 75 proteins were
found as increased and decreased, respectively, under PEG treat-
ment. Among the identifi ed proteins, only seven were found to be
mutual in two proteomics techniques. Increased abundance of cal-
nexin protein was evident under osmotic stress by both proteomic
approaches. Activation of plasma membrane H
+
-ATPase protein
implies acceleration of ion effl ux under hyperosmotic condition.
4.2 Plasma
Membrane Proteomics
4.3 Mitochondrial
Proteomics
Mitochondria have been a target for subcellular proteomic as most
of the abiotic stresses primarily impair mitochondrial electron trans-
port chain resulting excess ROS generation. Proteomics technique
coupled with metabolomics was successfully used to elucidate the
fl ooding stress impacts on mitochondrial function of fl ooded soy-
beans [
42
]. 2-DE and blue-native PAGE followed by nanoLC
MS/MS were used to separate and identify the differentially
