435

Advances in Metabolomics Research in Environmental Stress Response in Plants

allows the examination of samples in their natural state (Kang et al., 2019).

Integration of MS along with HPLC and ultra-high performance liquid chro­

matography (UPLC) provide a wide range for analysis of plant metabolome

profile (Theodoridis et al., 2012). Moreover, GC-MS further enhances the

importance of mass spectrometry due to its ability to detect volatile and

thermally unstable metabolites (Jorge et al., 2016). It can further be utilized

for probing primary metabolites such as sugar-phosphates, amino acids,

peptides, sugars, alkaloids, organic acids, ketones, and lipids. With recent

integration of other highly efficient mass spectroscopy techniques such as

matrix-assisted laser desorption ionization (MALDI) and desorption electro­

spray ionization mass spectrometry (DESI), it is possible to obtain high reso­

lution images that help us to completely understand the distribution of any

metabolite in any specific plant tissue or cell (Enomoto et al., 2018). Thus,

with all recent advancements, the metabolomics approach has appeared as

one of the more versatile strategies for studying the effects of abiotic stress in

plants as compared to that of genomics and proteomics approaches.

14.3 ELUCIDATION OF DROUGHT STRESS TOLERANCE IN PLANTS

Water scarcity or drought is an inevitable factor that hampers plant biomass,

energy production and grain yield. According to Brodersen et al. (2019);

and Abbasi & Abbasi (2010), around 80–95% of fresh biomass of plants is

mainly composed of water that plays a pivotal role in various physiological

processes of plants such as their metabolism, and growth and development.

Due to such wide role of water in plant physiology, some consider drought as

one of the main environmental stresses for plants that can eventually hamper

the food supply for the continuously growing population of the world in future

(Okorie et al., 2019). Passioura & Angus (2010) stated that the appearance of

drought stress depends on the uneven and undependable distribution of rain­

fall, water holding capacity of soil and evapotranspiration rate of that area.

Additionally, in some cases, in spite of water availability, plants are unable to

uptake that water from the soil, a phenomenon commonly known as pseudo-

drought or physiological drought (Salehi-Lisar & Bakhshayeshan-Agdam,

2020). Environmental factors such as drought frequency and intensity, plant

growth condition, characteristic of soil and plant species determines the

extent of negative effects of drought stress on plants (Zoghi et al., 2019).

Symptoms of water scarcity in plants can range from the production of ROS

that result in higher membrane lipid peroxidation, reduced photosynthesis,

CO2 uptake, ATP synthesis obstruction and oxidative damages in chloroplast