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Epigenetics unlocks
potential for
future crop improvement
I
n the current extreme climatic and economic conditions being
experienced across the world, researchers need to refocus on
required crop research.
Climate change is here to stay and the current severe drought
in South Africa is evidence of this. There is a need for research-
ers to adapt, fast track the adoption of new technologies, work
in larger international collaborations and refocus our areas of re-
search to supply producers with the tools to combat these climate
change challenges.
It has been well documented by world renowned scientists that the
21st century will bring with it increasingly severe fluctuations in
climatic conditions, causing more frequent drought (short and long-
term), flash flooding, dust storms and reduction in overall soil qual-
ity. Therefore, there is a pressing need to enhance the ability of crops
to grow, survive and perform in adverse environmental conditions.
Ultimately, breeders and pre-breeders still have only one long-term
goal in mind, to develop higher yielding cultivars that are more sta-
ble and able to produce good quality grain by means of better toler-
ance to extreme environments. This approach to crop improvement
will better equip the already challenged producers of South Africa.
Phenotypic variation or natural variation within crops is primarily
driven and exploited by the natural occurrence of genetic diversity.
Genetic diversity (variation) relates to differences (polymorphisms)
at the DNA sequence level that alter/modify gene expression, result-
ing in a particular phenotype being observed.
This genotype would be selected based on its superior performance,
stability and response to abiotic stresses across multiple environ-
ments and years. As a result, the design of any crop improvement or
plant breeding programme for decades has traditionally focused on
exploiting genetic variation.
However, a renewed research interest in epigenetics has gained
much importance and momentum in the last decade. It is the opinion
of plant researchers around the world that ‘epigenetics has begun to
leave a significant mark on future crop improvement and agriculture
in general’.
What is epigenetics?
Conrad H Waddington lay claim to the term epigenetics in 1942,
which was derived from the Greek word ‘epigenesis’ which originally
described the influence of genetic processes on development.
Epigenetics literally means ‘above’ or ‘on top of’ or ‘in addition to’
genetics. Epigenetics is a term generally used to describe the study
of a heritable change in gene expression that is independent of
DNA sequence.
The mechanism by which epigenetic information is inherited is
still unclear. Epigenetics forms part of the larger field of genetics.
SCOTT SYDENHAM,
ARC-Small Grain Institute, Bethlehem
Figure 1: The three main mechanisms for epigenetic gene regulation in plants: DNA methylation, histone modifications and RNA interference.
Saad
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March 2016