Omics approaches and abiotic stress tolerance in legumes - Legumes Under Environmental Stress: Yield, Improvement and Adaptations - page 217

Genomics

Functional

Genetic

genomics
Transgenomics

Transcriptomics

Molecular Proteomics

Response

Abiotic stress

Metabolic Metabolomics

Phenotypic

Phenomics

Figure 13.1

genomic data available on legumes, and the synteny
(similarity) present between various legume genomes
has further increased the applicability of the data avail-
able (Kalo et al., 2004; Stracke et al., 2004). These factors
make the two models extremely valuable for the study
of molecular and genetic responses of legumes to biotic
as well as abiotic stresses that hinder the yield of food
legume crops. Moreover, the sequencing of the soybean
genome and its high similarity with the model legume
systems can potentially facilitate various genetic proce-
dures for these studies, such as positional cloning. These
factors make the two models extremely valuable for the
study of molecular and genetic responses of legumes to
biotic as well as abiotic stresses that hinder the yield of
food legume crops.
Even though genome sequence information is of
great value and is a very important starting point, it is
not enough to decipher gene function, and the various
metabolic responses and regulatory pathways that are
activated when the legume is under stress conditions. In
order to circumvent these obstacles, approaches like the
quantitative and qualitative analysis of the products of
gene expression are very important. These need to be
carried out at the transcriptomic level as well as the
proteomic and metabolomic levels. Such expansive
knowledge will also facilitate a more targeted use of
transgenics and marker-assisted selection (Dita et al.,
2006). The 'omics' comprise of genomics, transcrip-
tomics, proteomics, metabolomics, functional genomics,
transgenomics and phenomics. Recent developments in

these various omics have substantially contributed to
greater comprehension of the molecular and genetic
levels of stress responses (Langridge & Fleury, 2011),
which were previously a bottleneck for transgenic
breeding and genetic modification of legumes. Significant
progress has been made in this regard on major legumes
like soybean, peanut and chickpea, which will be dis-
cussed in the chapter (Figure 13.1).

13.3 transcriptomics

The expression of any gene in a certain cell can only be
carried out once the gene has been transcribed. The link
between a gene and its translation into the protein
product is messenger RNA (mRNA), which is a result of
transcription. The set of all the mRNAs in a cell is known
as its transcriptome. Thus the investigation of various
populations of mRNAs in a cell, tissue or organism is
known as transcriptomics.
A very powerful tool for the study of gene expression,
transcriptomics gives an accurate representation of
the qualitative and quantitative gene expression of a
particular cell or tissue. Hence it can help identify candi-
date genes and reveal the crosstalk between different
gene regulatory pathways that take part in various
responses, as in a plant's response to abiotic stress
(Palovaara et al., 2013). Plants under abiotic stresses
usually face dehydration at the cellular level, and the
cellular water deficit mostly triggers genes normally