Epigenetics – The Molecular Tool in Understanding Abiotic Stress Response in Plants

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3’-CDS of ADH1 as well as PDC1 were methylated between H3K4me2 to

H3K4me3, whereas acetylation of H3 increased with longer exposure across

the ADH1 and PDC1 genes. Environmental stressors govern progressive

and bidirectional changes in H3K4 methylation and H3 acetylation under

stress-responsive genes of vascular plants (Tsuji et al., 2006). Plant cells

must recognize changes in O2 levels to activate hypoxia-reoxygenation

reactions. For plant cells to sense O2 levels, the integrity of transcriptional

regulators of group VII of the ethylene response factor family (ERFVIIS) is

crucial. Ethylene response factors VII (ERFVIIs) play a key role in ethylene

signaling and plant flooding responses; have an AP2 DNA-binding domain.

In Arabidopsis thaliana based on stage of development plants are confronted

by stress conditions. ERF-VII proteins have a dual role under submergence:

as activator of the hypoxic response and as negative modulator of the

oxidative-stress associated gene (Giuntoli et al., 2017).

Azahar et al. in 2020 discovered and characterized submergence sensi­

tive miRNAs in maize seedlings using two sRNA libraries of normal and

treated (submergence) maize roots. They discovered 524 identified miRNAs

as well as 48 new ones. Submergence responsive miRNAs have been

linked to a number of cellular activities, involving growth and development

(miR172a, miR393b-3p), hormone signaling routes (miR159c,f, miR160f­

5p, miR167d-3p, miR172a, miR393a-5p), and oxidoreduction equilibrium

(miR164a,b,c-5p, miR166h, a-3p, miR167 (miR156d-3p, miR159c,f,

miR169c-3p Overexpression of ERTF RAP2-7 ISOFORM X2 by miR172a

may have been a basic requirement for the change from oxygenated to less

efficient non-oxygenated fermentation, resulting in limited plant develop­

ment during submerged conditions. The data suggest that dysregulation of

the ROS scavenging system may be a key determinant in maize seedlings’

poor performance under submerged conditions. The study contributes new

perspectives of maize saplings’ post-transcriptional stress response mecha­

nisms to submergence stress.

12.3 ENVIRONMENTAL STRESS AND AGRICULTURE

Abrupt environmental changes have a significant impact on the ecosystem,

public health, as well as crop yield (Arunanondchai et al., 2018). The fast

expansion of the global population has resulted in a proportionate increase in

food consumption. Agricultural productivity is heavily influenced by water

supply, poor air quality, and soil nutrients (Noya et al., 2018). In response to