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

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al., 2010). Arsenic (As) is a non-essential, extremely toxic, class-I carci­

nogenic metalloid that is harmful to all living things, including plants. It is

that is widely dispersed in the earth’s crust and poses serious health risks to

humans when it enters the food chain via contaminated food crops. Arsenic

reaches plants through phosphate transporters or aquaglycoporins as a

phosphate analog. Arsenic uptake in plant tissues has a negative impact on

plant metabolism and causes a variety of physiological as well as structural

problems (Srivastava et al., 2012). For exploring more about miRNA’s

function in selenium’s antagonistic impact on arsenic stress of rice saplings,

researchers discovered that combination of Se and As reduced detrimental

roles of As on sapling sprouting, root-shoot development, chlorophyll, and

protein content. When rice seedlings were exposed to As, Se, or As with Se,

miRNA microarray analysis revealed significant modulation of 46 miRNAs

relative to the unmodified control. Depending on the dosage, 18 of such

miRNAs had varying levels of regulation. There may be a probable effect

of miR395 and miR398 in the counter effect on the unfavorable response

of As in rice seedlings in the existence of Se (Pandey et al., 2015). The

impact of As-stress on rice plants was investigated at several developmental

phases (saplings, tillering, and blooming) and varied tissues of the foliage,

stem, and root under a 25 M arsenite [As(III)] exposure (at 0, 24, 48, and

72 h). Expression of Osa-miR156j, an associate of the miR156 gene group

that regulates plant growth and development was studied under the effect

of arsenic toxicity at various phases of physiological growths. In various

developmental phases, the expression of Osa-miR156j revealed a temporal

↓ in multiple organs. In comparison to other tissues, the ↓ was evident high

in root tissues at saplings, plant with a tiller, and blooming phases in 0–72

h with arsenite treatment. From this study, it is evident that the microRNA

Osa-miR156j could be beneficial in the generation of arsenic-tolerant plants

(Pandey et al., 2020). Aluminum (Al) is a major poisonous factor for crop

production since they adhere to –COOH and PO4 groups in the root cell

wall, causing architectural alterations, inhibition of cell wall extension, and

reduced root expansion. Through miRNA expression patterns and in silico

study of target genes, a group of researchers studied the probable Al³⁺ stress

tolerating mechanisms of sugarcane. They found miR395 is associated with

Al³⁺ elimination, while miR160, miR6225-5p, and miR167 were found to be

involved in lateral root development, conferring genotype tolerance. These

results could aid funding to future genetic improvement programs focused on

developing sugarcane genotypes that are resistant to abiotic stress, as well as

biotechnological efforts aiming at miRNA suppression or gene upregulation.