Molecular and Morphophysiological Analysis of Drought Stress in Plants

Abstract

Drought is a major environmental stress factor that affects the growth and development of plants. Most of the physiological traits associated with drought tolerance are quantitative in nature. An important research strategy that has been widely used to deal with such complexity is to use molecular markers to identify quantitative trait loci (QTLs) in appropriate mapping populations. In response to drought brought about by soil water deficit, plants can exhibit either drought escape or drought resistance mechanisms, with resistance further classified into drought avoidance and drought tolerance. Drought escape is the ability of plants to complete the life cycle before severe stress arrives. Drought avoidance is the maintenance of high tissue water potential in spite of soil water deficit. Drought avoidance is consequence of improved water uptake under stress and the capacity of plant cells to hold acquired water that reduces water loss. Drought tolerance is the ability to withstand water deficit with low tissue water potential. Plant water status that includes leaf water potential, osmotic potential and relative water content (RWC) represents an easy measure of water deficit and provides best sensor for stress. Genomics-assisted breeding (GAB) approaches, such as markerassisted selection (MAS), can greatly improve precision and efficiency of selection in crop breeding. Molecular markers can facilitate indirect selection for traits that are difficult or inconvenient to score directly, pyramiding genes from different sources and combining resistance to multiple stresses. Conventional breeding for developing drought-tolerant crop varieties is time-consuming and labor intensive due to the quantitative nature of drought tolerance and difficulties in selection for drought tolerance. The identification of genomic regions associated with drought tolerance would enable breeders to develop improved cultivars with increased drought tolerance using marker-assisted selection (MAS). This requires integration of knowledge from plant physiology and biotechnology into plant breeding. The availability of a large number of molecular markers, dense genetic maps and markers associated with traits and transcriptomics resources have made it possible to integrate genomics technologies into chickpea improvement.

Irrigation affects characteristics of narrow-leaved lupin (Lupinus angustifolius L.) seeds

“…Drought tolerance is an ability to endure low water potential by, e.g., accumulation of osmolytes increasing the osmotic potential and higher water uptake by roots. Shortage of water is accompanied by oxidative stress and excessive formation of ROS may cause damages in photosystems or cell membranes (Moran et al 1994;Farooq et al 2009;Osakabe et al 2014;Yadav and Sharma 2016).…”

“…Since shortage of water reduces crop yield, intensive research to produce drought resistant crops is being conducted. However, the complexity of responses to drought makes these studies difficult and time-consuming (Farooq et al 2009;Yadav and Sharma 2016;Cantale et al 2018). Thus, different methods of irrigation are still the most common approach to reduce adverse effects of water deficit in agriculture.…”

Drought tolerance during reproductive development is important for increasing wheat yield potential under climate change in Europe

“…Ph was smaller in the DS ideotype compared with DT, indicating a relatively higher chance for DS to escape any terminal drought by early flowering and maturity due to the shorter vegetative stage. Early flowering and maturity are important drought escape traits for many crops including wheat (Yadav and Sharma, 2016; Shavrukov et al , 2017). Greater Ru values for DS compared with DT indicate that drought-sensitive cultivars could take up soil water faster to avoid current drought stress.…”

“…Plants deploy many strategies and adaptations for survival and complete the life cycle in different ways under water stress, viz. drought escape, avoidance, and tolerance (Farooq et al , 2014; Yadav and Sharma, 2016). Drought tolerance is a complex trait controlled by many individual plant traits with small contributions (Semenov and Halford, 2009; Fleury et al , 2010; Hu and Xiong, 2014).…”

QTL Mapping for Drought-Responsive Agronomic Traits Associated with Physiology, Phenology, and Yield in an Andean Intra-Gene Pool Common Bean Population

“…Drought avoidance is facilitated by the maximization of water uptake by the root system and optimization of water consumption by shoots resulting in greater biomass production in relation to transpired water [5]. An important characteristic of drought tolerance is osmotic adjustment with an accumulation of compatible solutes [6].…”