Omics approaches and abiotic stress tolerance in legumes - Legumes Under Environmental Stress: Yield, Improvement and Adaptations - page 221

Control condition Abiotic stress condition

Proteome pro ling Proteome pro ling

Differential analysis

Stress induced
candidate proteins

Figure 13.2

patterns, the long-term abiotic stress-induced response
in soybean was traced and the similarities along with the
differences between the responses to osmotic stress and
cold stress were distinguished.
The effects of flooding on the cultivation of soybean
have also been studied by employing proteomics tech-
niques (Komatsu et al., 2012; Ohyanagi et al., 2012).
Flooding is highly detrimental as it causes a marked
reduction in growth and grain yield of soybean.
Komatsu and colleagues used two proteomics tech-
niques to investigate the extent of alteration in the
endoplasmic reticulum (ER)-enriched fraction of
soybean exposed to the stress of flood. Two-day-old
soybean seedlings were exposed to flood stress for 2
days, after which the purified rough ER-enriched
fraction was obtained from the root tips. The flooding-
responsive proteins of this fraction were then identified
using gel-free as well as 1D-gel-based proteomics tech-
niques. Comparative proteomics analysis yielded an
increase of 117 proteins and a decrease of 212 proteins
in the soybean root tips exposed to flooding conditions.
A total of 111 of these proteins were found to be
involved in the synthesis of proteins, post-translational
modification, protein folding, protein activation and
protein degradation. Analysis of the mRNA expression
levels of 14 of the differentially regulated proteins

thought to be localized in the ER was carried out.
Under 1 day of the flooding condition, 3-ketoacyl-CoA
reductase 1 up-regulation was observed, whereas the
downregulation of eight genes related to hormone
metabolism, cell wall repair and DNA repair was
observed. Specific induction of the expression of lumi-
nal-binding protein 5 also occurred in these roots,
while methyltransferase PMT 2 along with arabinoga-
lactan protein 2 were found to be downregulated. The
results showed that flooding significantly affects the
profile and level of protein synthesis and also glycosyl-
ation in the endoplasmic reticulum in the root tips of
the soybean plants exposed to flooding stress.
These studies show that a proteomics approach can be
used not only to differentially analyse the proteome of
legumes under various abiotic stress conditions as well as
control conditions, but also to identify candidate proteins
that can help decipher the stress-responsive mechanisms
of commercially important legumes (Figure 13.2).

13.5 Metabolomics

Metabolites are a reflection of the expression of genes,
the interaction of proteins and various other processes
responsible for gene regulation; they are closer to the