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Biology and Biotechnology of Environmental Stress Tolerance in Plants, Volume 3

have multiple responses to environmental stresses is very important for the

resilience of crops to environmental distresses.

8.1 INTRODUCTION

Environmental stress are some of the factors limiting the growth and yield of

crops and plays an important role in the ecological distribution of plants. The

most important environmental stresses are heat, cold, salinity, and drought. To

deal with these stresses, plants regulate the expression of various genes in the

nucleus, cytoplasm, chloroplasts, and other organelles (Zhang et al., 2020).

In plant adaptation to stress, several mechanisms are activated at the

molecular, biochemical, and physiological levels that contribute to yield

stability. The ability to respond to environmental stresses in different types

of plants, and even different plant species is different and needs further

investigation. Studies have shown that several systems of regulation of gene

expression are involved in the response to stress (Shinozaki & Yamaguchi-

Shinozaki, 1997). Accurate knowledge of tolerance mechanisms and genes

involved in stress response can improve tolerance to various stresses in crops

by methods such as genetic engineering. Therefore, identifying and under­

standing different pathways of response to stresses has a very important role

in improving plant performance (Lee et al., 2005).

Transcriptomics refers to RNA copies of a particular type of cell or tissue

under specific developmental, physiological, and environmental conditions

and includes rRNA, tRNA, mRNA, and non-coding RNA. The transcriptome

of each cell is the expression pattern of actively expressed genes at a particular

time; mRNA degradation also affects the transcriptome. Transcriptomics

focuses on the expression of genes by examining RNAlevels (Taft et al., 2010).

Microarray technology is one of the first tools for transcriptome analysis

in the last two decades, which can study the expression levels of thousands

of genes simultaneously and provides a profile of the gene expression

under stress. In addition, DNA microarray today provides the basis for next

generation sequencing (NGS) (Wöhrle et al., 2020) and the models in how

the research, techniques, and knowledge in life sciences and biotechnology

(including genomics, proteomics, and bioinformatics) would be conducted,

presented, and used (Fajriyah, 2021). Identification and selection of respon­

sive genes that increase resistance to environmental stresses in plants is very

important. Using techniques such as DNA microarrays, hub genes can be

introduced and then used to improve plant resistance to stress. The different

aspects of using the microarray technique are explained in this chapter.