Phytohormones as Growth Regulators During Abiotic Stress Tolerance in Plants

Abstract

Phytohormones (PHs) play crucial role in regulation of various physiological and biochemical processes that govern plant growth and yield under optimal and stress conditions. The interaction of these PHs is crucial for plant survival under stressful environments as they trigger signaling pathways. Hormonal cross regulation initiate a cascade of reactions which finely tune the physiological processes in plant architecture that help plant to grow under suboptimal growth conditions. Recently, various studies have highlighted the role of PHs such as abscisic acid, salicylic acid, ethylene, and jasmonates in the plant responses toward environmental stresses. The involvement of cytokinins, gibberellins, auxin, and relatively novel PHs such as strigolactones and brassinosteroids in plant growth and development has been documented under normal and stress conditions. The recent identification of the first plant melatonin receptor opened the door to this regulatory molecule being considered a new plant hormone. However, polyamines, which are not considered PHs, have been included in this chapter. Various microbes produce and secrete hormones which helped the plants in nutrient uptake such as N, P, and Fe. Exogenous use of such microbes help plants in correcting nutrient deficiency under abiotic stresses. This chapter focused on the recent developments in the knowledge related to PHs and their involvement in abiotic stresses of anticipation, signaling, cross-talk, and activation of response mechanisms. In view of role of hormones and capability of microbes in producing hormones, we propose the use of hormones and microbes as potential strategy for crop stress management.

Impact of 24-epibrassinolide, spermine, and silicon on plant growth, antioxidant defense systems, and osmolyte accumulation of maize under water stress

“…The two hormones, ABA and ethylene, have been extensively investigated to date and have shown activation and provision of tolerance under conditions of low water deficit 26 , 27 . During drought, the other key hormones, including auxin, CKs, and GA, also play a substantial role, albeit the molecular processes behind these hormones are only poorly known 28 , 29 . In addition, the other growth regulators such as brassinosteroids, SA, and jasmonic acid (JA), are also crucial in coping with drought 30 .…”

Physiological and biochemical responses of selected weed and crop species to the plant-based bioherbicide WeedLock

“…Salicylic acid potentially controls, either directly or indirectly, the activity of antioxidant defence enzymes and alters plant responses to multiple stress 52 , 53 , including those caused by herbicides 54 , 55 . Both phytohormone-ethylene and gibberellin serve important roles in mitigating stress by activating defence regulatory genes 56 . Several genes were associated with gibberellin and phytoalexin production and Mitogen activated protein kinase signaling were downregulated by caffeic acid, resulting in growth inhibition of Setaria viridis (L.) P.Beauv 57 .…”

On the human health benefits of microalgal phytohormones: An explorative in silico analysis

“…Phytohormones (PHs) are among the less investigated secondary metabolites in microalgae and therefore require scientific efforts to unravel their potential biotechnological interests [8] , [9] . Phytohormones, a group of small bioactive secondary metabolites present in all photosynthetic organisms [10] are conserved polyfunctional molecules from different families, including auxins (AUXs), cytokinins (CKs), gibberellins (GAs), jasmonic acid (JA), abscisic acid (ABA), salicylic acid (SA), strigolactones (SLs) and brassinosteroids (BRs). They contribute into many relevant plant functions, such as cell division, homeostasis, growth, modulation of plant-microbe interactions, defense against pathogens, phototropism or memory [10] .…”