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Molecular Plant Breeding 2011, Vol.2, No.14, 98
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of the most important cereals in our food chain on this
planet. One major challenge for agriculture is to
produce more food with less water. Rice is mainly
grown in submerged conditions, but there is a need to
develop strategies for growing rice under low
moisture conditions (Bouman and Tuong, 2001).
Looking at the present climatic changes, it is predicted
that there will be frequent and severe droughts in the future.
OMICS based technologies are of great value for crop
improvement. Genomics based approaches such as
utilization of molecular markers has uncovered its
potential for crop improvement. Ma et al., (2004)
conducted bulked segregant analysis experiment using
microsatellite and expressed sequence tag (EST)-
based PCR markers for mapping Si transporter gene.
The gene was mapped to chromosome 2, and the
microsatellite marker RM5303 and EST-based PCR
marker E60168 were shown to flank this gene.
So taking into consideration the role of Si in
enhancing tolerance to various biotic and abiotic
stresses, importance of rice and the potential of
OMICS based technologies we here propose the
strategies that can be utilized for improvement of rice crop.
1 OMICS based strategy for exploring the
potential of Si in rice crop improvement
Genomics and proteomics technologies are presently
well utilized to mine novel genes and potential
candidate proteins. Though genomics will cover large
number of approaches, here we will focus on
Molecular Marker Assisted Back Cross (MABC)
approach for accumulation of higher Si in rice. In case
of proteomics study we will discuss a strategy through
which novel proteins can be identified and used as the
candidates for manipulating various metabolic proce-
sses to enhance tolerance of rice to various stresses.
1.1 Molecular breeding for enhancing accumulation
of Si in rice
Through molecular breeding, it is feasible to transfer
higher Si accumulation trait in elite rice cultivars. As
Si transporter gene has been mapped on chromosome
2 by EST and microsatellite marker (Ma et al., 2004)
the molecular markers linked to
lsi
1 are known (Ma
et al., 2006). Hence these markers can be utilized in
screening the available rice germplasm to identify the
parental sources. The cultivar with highest Si content
can be used as a donor parent for transferring the trait
in an elite variety through backcrossing. The molecular
markers can be utilized for both background and
foreground selection after every back cross, to have
higher Si accumulation trait in the elite cultivar. For
background selection markers will be selected
randomly from all 12 rice chromosomes of rice
genetic map. It will be desirable to select the markers
in such a way that whole chromosome is covered
(equal distributed markers). Such marker should show
polymorphism among the parents. And for foreground
selection the already mapped markers can be uitilised
(RM5303 and E60168) along with fine mapped
markers that can be identified from the rice genetic
map. It is desirable to go for selection after every back
cross, so that after three backcrosses and selfing
(BC3F3), we can get the plants with desirable trait
(higher Si accumulation). The strategy is explained in
Figure 1.
Figure 1 Molecular marker assisted backcrossing for trans-
ferring of high Si accumulation trait in an elite cultivar
1.2 Proteomics based strategy to identify novel
proteins induced due to application of Si
In this approach, it will be possible to resolve and
identify all the proteins that get differentially regulated
by application of Si. 2
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DGE (two dimensional gel