Prospects for the application of jasmonates, salicylates, and abscisic acid in agriculture to increase plant stress resistance (review)

Nowadays, the search for new effective methods and approaches based on using natural bioactive compounds that control plant growth, development, and plant productivity with minimal impact to the environment and human health is still in great demand. One of the directions developing during the last decades contributing to the “greening” of agricultural production is the application agrochemicals based on phytohormones with protective functions, such as abscisic acid, salicylic acid, and jasmonates. The use of these phytohormones is very promising since it can significantly increase plant tolerance to unfavorable factors of biotic and abiotic nature. This review summarizes the current information on the biological functions of abscisic acid, jasmonates, and salicylates, presents the examples demonstrating crop species treatment with the agrochemicals based on these phytohormones, and discusses the promising directions for the phytohormones application in agriculture. Abscisic acid, jasmonates, and salicylates are often referred to as stress hormones because they regulate the plant adaptive responses to adverse environmental conditions. Abscisic acid is a regulator of plant growth and development throughout ontogenesis, as well as tolerance to abiotic and biotic stress factors (J. Li et al., 2017), plays a role in the stomata closure, regulating the ion flow in the guard cells, controls all stages of seed maturation (K. Chen et al., 2020). Abscisic acid can play positive and negative roles in plant protection against pathogens (L. Lievens et al., 2017; K. Xie et al., 2018) and influence the symbiotic relationships with fungi and bacteria (A. Tsyganova, V. Tsyganov, 2015). Salicylic acid controls plant tolerance to pathogens (A. Vlot et al., 2009; P. Ding, Y. Ding, 2020), plays a role in the development of hypersensitive response, death of infected cells (D. Klessig and J. Malamy, 1994; M. Alvarez, 2000), and formation of tolerance in unaffected plant parts (systemic acquired resistance) (M. Bürger, J. Chory, 2019). Salicylic acid may also be involved in the enhancement of plant tolerance to salt and low temperature stress (E. Horvath et al., 2015; Yu. Kolupaev, Yu. Karpets, 2021; W. Wang et al., 2018) and maintenance of the root zone microbiome (S. Lebeis et al., 2015). The range of regulatory effects of jasmonates is broad, but their functions are primarily associated with the regulation of mechanisms that determine plant tolerance to necrotrophic pathogens and insects, including root pests (C. Rohwer, J. Erwin, 2008; S. Johnson et al., 2018). Jasmonates also control plant tolerance to low temperature, salt stress, flooding, drought, ozone, heavy metals, and ultraviolet radiation (T. Savchenko et al., 2014; D. Pandita, 2022; T. Savchenko et al., 2019; K. Kazan, 2015; H. Kim et al., 2021). The high biological activity of abscisic acid, salicylates and jasmonates determines the significant potential of their application in agriculture to increase plant stress tolerance. At the same time, according to published data, the increase in plant tolerance mediated by the mentioned phytohormones is often accompanied by the suppression of growth-related processes, which can adversely affect crop yields and product quality. To assess the prospects for the practical use of agrochemicals based on abscisic acid, jasmonates, and salicylic acid, a comprehensive analysis of the available data on the physiological effects caused by these substances is necessary due to their spectrum of actions, dependent on species/variety specificity, phase of plant development, susceptibility of the target tissue, chemicals concentration, duration of treatment and conditions of application.