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

since few decades it has gained the focus of extensive research to unlock the

complicated mechanisms entailed in salt tolerance in plants. In comparison

to other abiotic stresses, salinity is quite complex as it exerts both osmotic

and ionic action that accelerates its toxicity greatly (Parmar et al., 2020).

Plants also develop various adaptive measures to exclude excess salt from

the cell and also develop some modifications to tolerate salt within their cells

for survival under salinity (Munns & Tester, 2008). Different plant species

show different adaptive features under salinity and their responses also vary

to salinity. In most cases, salt-sensitive plants experience osmotic stress,

ionic toxicity, and oxidative stress and in severe cases, salinity causes the

death of the plant; on the contrary, to cope with salinity, salt-tolerant plants

employ a variety of morphological, physiological, and molecular processes

(Bartels & Sunkar, 2005; Munns & Tester, 2005; Zhang & Shi, 2013). Excess

salinity inhibits water uptake by the root system and reduces turgor pressure

water efflux from the vacuole, thereby causing insufficient osmotic imbal­

ance (Devkar et al., 2020). Any salt-sensitive plant growing under salinity

suffers from triple-fold impacts, viz. osmotic stress, ionic stress, and oxida­

tive stress and thus become incapable to grow further (Khare et al., 2015;

Surekha et al., 2015; Wani & Gosal, 2010). There is a real need for some

effective strategies for developing salt-tolerant cultivars and salt remedia­

tion. Most of the crop plants that are salt sensitive are called glycophytes. To

defend and survive during salt-induced stress conditions glycophytic plants

have developed elaborate and systematic sensory and adaptive responses

including gene transcription network and activation of signaling cascade

(Joshi et al., 2016; Kinoshita & Seki, 2014; Wani et al., 2013). Plant stress

tolerance usually associated with morphological, physio-chemical, and

molecular mechanisms, which are ultimately regulated by genes. Based on

the model plant Arabidopsis researchers have identified many genes which

are required for salt tolerance and a few of them are successfully used to

increase salt tolerance levels in some agriculturally important crop cultivars

through genetic engineering and biotechnological approaches (Zhao et al.,

2020). Plant breeders of every corner of the world seek to develop and

identify cultivars that are more tolerant towards salinity. Many genes are

critically involved in several kinds of plant responses against salt-induced

stress. Some of the genes are associated with the activation of ion chan­

nels, whereas others are count in signal transduction and modification of

growth-regulating factors for plant architecture, chiefly root morphology

(Mirlohi & He, 2016). Every response of plants to salt stress is the result of

a complex and dynamic mechanism governed by many gene loci and carried