Scrutinizing the impact of water deficit in plants: Transcriptional regulation, signaling, photosynthetic efficacy, and management

Abstract

Suboptimal availability of water limits plant growth, development, and performance.Drought is one of the leading factors responsible for worldwide crop yield reduction. In the future, owing to climate changes, more agricultural land will be affected by prolonged periods of water deficit. Thus, understanding the fundamental mechanism of drought response is a major scientific concern for improvement of crop production. To combat drought stress, plants deploy varied mechanistic strategies and alter their morphological, physiochemical, and molecular attributes. This helps plant to enhance water uptake and storage, reduce water loss and avoid wilting. Induction of several transcription factors and drought responsive genes leads to synthesis of stress proteins, regulation of water channels i.e. aquaporins and production of osmolytes that are essential for maintenance of osmotic balance at the cellular level. Self-and hormone-regulated signaling pathways are often stimulated by plants after receiving drought stress signals via secondary messengers, mitogen-activated protein kinases, and stress hormones. These signaling cascades often leads to stomatal closure and reduction in transpiration rates. Reduced carbon dioxide diffusion in chloroplast, lowered efficacy of photosystems, and other metabolic constraints limits the key regulatory photosynthetic process during water deficit. The impact of these stomatal and nonstomatal limitations varies with stress intensity, superimposed stresses and plant species. A clear understanding of the drought resistance process is thus important before adopting strategies for imparting drought tolerance in plants. These management practices at present include exogenous hormone application, breeding, and genetic engineering techniques for combating the water deficit issues.

Leafamine®, a Free Amino Acid-Rich Biostimulant, Promotes Growth Performance of Deficit-Irrigated Lettuce

“…During a water shortage, plants can establish molecular and biochemical responses [3,4] that cause morphological and physiological changes in fine. Although the understanding of the signaling network underlying these changes is still in progress [5,6], plant responses to water deficit are well characterized. They include morphological changes, mainly marked by a reduction of the leaf area and biomass [4].…”

New drought‐adaptive loci underlying candidate genes on wheat chromosome 4B with improved photosynthesis and yield responses

“…Plant drought resistance is associated with drought escape via a short life cycle or developmental flexibility (early germination, faster plant growth, early flowering, and maturity; Manavalan et al 2009), drought avoidance as a means of enhanced water uptake, reduced water loss, leaf rolling, reduced leaf area, decline in leaf growth, and adjustment in root growth (Tardieu & Parent 2017). More importantly, photosynthesis is a key physiological process in plants, diversely affected by drought stress (Bano et al 2021;Kaur et al 2021). The mechanism underlying photosynthesis decline in response to drought stress is owed to (1) a reduction in chlorophyll biosynthesis, (2) stomatal and nonstomatal limitations, (3) a decrease in mesophyll conductance to CO 2 , (4) an increase in accumulation of reactive oxygen species (ROS) that rapidly react with the cellular lipids and proteins, and (5) inhibitions of enzymatic activities involved in carboxylation processes (Flexas et al 2004;Farooq et al 2009;Flexas et al 2009).…”

Physiological and Molecular Aspects of Two Thymus Species Differently Sensitive to Drought Stress

“…As expected, the four irrigation regimes resulted in a reduction in RWC because of the decreased water availability. RWC reduction causes an alteration in the transpiration processes, leading to stomata closure [42]. This event determines a reduction in the photosynthetic processes due to a decrease in CO 2 [43].…”