Biology Reference
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identify 422 proteins primarily involved in plant metabolism,
protein destination and storage, metabolite transport, and disease/
defense. An overall decrease in metabolism-related proteins versus
an increase in proteins associated with destination and storage was
observed during seed fi lling. A user-intuitive database (
http://oil-
seedproteomics.missouri.edu
)
was constructed to access all expres-
sion profi le data for proteomics research on soybean and other
oilseeds plants.
Barbosa et al. [
21
] have recently compared the expression pat-
terns of seed proteins of non-transgenic soybean variety with that
of transgenic soybean which confers resistance to the herbicide
glyphosate-
N
-(phosphonomethyl)glycine. After separation of seed
proteins by 2-DE, 192 proteins were identifi ed using MALDI
quadrupole time-of-fl ight (QTOF) MS and electrospray ionization
(ESI) QTOF MS. Majority of the identifi ed proteins (50 %) were
related to storage function. The second most abundant class of
proteins (18 %) was found to be involved in cell growth/cell divi-
sion. Authors were successful in identifying the enzyme CP4
EPSPS, involved in the genetic modifi cation by ESI-QTOF MS/
MS and using trypsin as a cleavage enzyme. Using two-dimensional
difference gel electrophoresis (2D-DIGE) technique actin frag-
ment, cytosolic glutamine synthetase, glycinin subunit G1, and
glycine-rich RNA-binding protein were shown to be differentially
expressed in transgenic seeds. In addition, transgenic seeds
exhibited higher level of lipid peroxidation and increased activity of
reactive oxygen species (ROS) scavenging enzymes. These fi ndings
led them conclude that the transgenic seeds experienced higher
level of stress even when no herbicides were used.
Stress induced changes in protein profi ling of soybean at young
seedling stage have been well explored. Alam et al. [
27
] carried out
proteomic analysis of 2 weeks old soybean roots exposed to water-
logging stress. 2-DE technique was exploited to separate the pro-
tein spots. Five novel proteins viz. translation initiation factor,
apyrase, auxin-amidohydrolase and coproporphyrinogen oxidase
induced under waterlogging condition were identifi ed by MALDI-
TOF MS or ESI-MS/MS analysis. Functional analysis revealed
that these proteins were involved in signal transduction, pro-
grammed cell death, RNA processing, redox homeostasis and
metabolisms of energy. Waterlogging induces progressive reduc-
tion in soil O
2
concentration, creating an anaerobic condition
around the root zone. Higher abundance of proteins involved in
glycolysis and fermentation pathway suggests that stressed plants
meet their energy requirement through fermentation process.
Authors propose that the soybean plant cope with the waterlogged
condition through the management of carbohydrate consumption
and by regulating programmed cell death.
3.2 Young Seedling
Stage
