Epigenetics: Applications in crop improvement
Author: Dr. Sunil Gomashe Co-authors: Ganapathy, KN and Smita Shingane

Epigenetics has gained much importance from last decade. It has made significant mark in crop improvement and ultimately to agriculture. Epigenetics deals with the heritable processes that are not coded by the major genetic material i.e. DNA and RNA. Plants mostly use three mechanisms for epigenetic gene regulation viz., DNA methylation, histone modifications and RNA interference (RNAi). Epigenetic changes once established then these can be inherited generation to generation. These are inherited through epigenetic alleles and this may give rise to higher polymorphism and ultimately to newer phenotypes. The crop improvement process is mainly dependent on the new source of variation.

This heritable variation provides basis for selection in plant breeding. Due to availability of novel phenotypes through epigenetic processes it has lot of applications in crop improvement.

1) Improvement in Nutritional value
By using the RNAi technology the genes can be expressed at specific stage of the crop. It has been used in many crops for nutritional improvement like in cotton it was used to develop low gossypol lines, for increasing grain amylase content in wheat, in bringing down BOAA (β- oxalylamino alanine-L-alanine) levels from Lathyrus , fruit quality in tomato, coffee with very low caffeine content (Angaji et al. 2010).

2) Dosage compensation or parental imprinting
Epigenetic studies have been conducted to know its implications in controlling the contribution of parents in seeds or endosperm development. It was observed that the characteristics of seeds in Arabidopsis were significantly affected due to changes in parental genome dosage (Scott et al. 1998). This could be very useful in heterosis breeding to manipulate contribution of parents.

3) Increasing stress tolerance in plants
These technologies could be effectively used for the down regulation of the stress related genes for drought, salinity, heat, cold etc. In rice the RNA mediated disruption of some genes resulted in the drought tolerance at vegetative and reproductive stages (Manavalan et al. 2012).

4) Improvement in virus resistance in plants
RNAi technology has been fruitfully used in banana for production of varieties resistant to Banana Bract Mosaic Virus (BBrMV) and in barley for Barley Yellow Dwarf Virus (BYDV).

In addition to these applications, epigenetic research has greater role in manipulating plant architecture, flower colour, flowering time, in forestry for wood quality etc.

1. Angaji, A,S. et al. 2010, Application of RNA interference in plant.Plant Omics Journal, 3:77-84
2. Manavalan, L. P. et al 2012, RNAi-mediated disruption of squalene synthase improves drought tolerance and yield in rice, Journal of Experimental Botany, 63: 163-175.
3. Scott, R.J.,1998, Parent-of-origin effects on seed development in Arabidopsis thaliana. Development 125:3329-3341.

About Author / Additional Info:
Scientist working in Indian Council of Agricultural Research (ICAR)