Nitric oxide and phytohormone interactions: current status and perspectives

Abstract

Nitric oxide (NO) is currently considered a ubiquitous signal in plant systems, playing significant roles in a wide range of responses to environmental and endogenous cues. During the signaling events leading to these plant responses, NO frequently interacts with plant hormones and other endogenous molecules, at times originating remarkably complex signaling cascades. Accumulating evidence indicates that virtually all major classes of plant hormones may influence, at least to some degree, the endogenous levels of NO. In addition, studies conducted during the induction of diverse plant responses have demonstrated that NO may also affect biosynthesis, catabolism/conjugation, transport, perception, and/or transduction of different phytohormones, such as auxins, gibberellins, cytokinins, abscisic acid, ethylene, salicylic acid, jasmonates, and brassinosteroids. Although still not completely elucidated, the mechanisms underlying the interaction between NO and plant hormones have recently been investigated in a number of species and plant responses. This review specifically focuses on the current knowledge of the mechanisms implicated in NO–phytohormone interactions during the regulation of developmental and metabolic plant events. The modifications triggered by NO on the transcription of genes encoding biosynthetic/degradative enzymes as well as proteins involved in the transport and signal transduction of distinct plant hormones will be contextualized during the control of developmental, metabolic, and defense responses in plants. Moreover, the direct post-translational modification of phytohormone biosynthetic enzymes and receptors through S-nitrosylation will also be discussed as a key mechanism for regulating plant physiological responses. Finally, some future perspectives toward a more complete understanding of NO–phytohormone interactions will also be presented and discussed.

Salinity effects on photosynthetic pigments, proline, biomass and nitric oxide in Salvinia auriculata Aubl.

“…The increases observed in S. auriculata FW and DW associated to higher NO content have been demonstrated in other studies, resulting in leaf expansion, for example (An et Regarding NO diffusion, NO can also diffuse into the cell from production sites, such as the mitochondria, to other regions of the cell, which can then produce an effect by interaction with target proteins (Freschi, 2013). It is also possible that NO can diffuse out of the cell through the plasma membrane to adjacent cells to stimulate its effect (Neill et al, 2008).…”

NO signaling is a key component of the root growth response to nitrate inZea maysL.

“…Moreover, since NO and auxin act synergically to control diverse aspects of root biology (for a review see Freschi et al 84 ) and lateral root development in response to nitrate is strongly auxin dependent, 85 a role of NO as a coordinator of nitrate and auxin signaling to control the overall root response to the anion cannot be excluded. The involvement of nitric oxide homeostasis control in the root elongation response to nitrate 68 adds a novel component to the complicated puzzle of the root adaptation to nitrate fluctuations in soil (Fig.…”

Exogenous nitric oxide donor sodium nitroprusside ameliorates root architecture and growth performance in young budding polybagged plants of rubber (<em>Hevea brasiliensis</em>)

“…Studies conducted during the induction of diverse plant responses have demonstrated that NO may also affect biosynthesis, catabolism/ conjugation, transport, perception, and/or transduction of almost all the phytohormones, i.e. auxins, gibberellins, cytokinins, abscisic acid, ethylene, salicylic acid, jasmonates, and brassinosteroids (Freschi, 2013). During the signaling events leading to these plant responses, NO frequently interacts with plant hormones and other endogenous molecules, at times originating remarkably complex signaling cascades (Freschi, 2013).…”

“…auxins, gibberellins, cytokinins, abscisic acid, ethylene, salicylic acid, jasmonates, and brassinosteroids (Freschi, 2013). During the signaling events leading to these plant responses, NO frequently interacts with plant hormones and other endogenous molecules, at times originating remarkably complex signaling cascades (Freschi, 2013). Instead of a unique or very few receptors, NO likely interacts with a wide range of target proteins via direct modification of protein structure (Freschi, 2013).…”

“…To effectively carry out such critical function, distinct plant hormones intensively interact among themselves and also with other endogenous signaling substances (Santner et al, 2009). Among these hormone-interacting molecules, the gaseous free radical nitric oxide (NO) has recently gained special interest in the research community given its involvement in a number of signaling cascades controlling plant responses ranging from seed germination to plant senescence (Mur et al, 2012;Freschi, 2013;Kong et al, 2014). NO is required for root organogenesis (Pagnussat et al 2002), the formation of adventitious roots (Pagnussat et al, 2003), lateral root development (CorreaAragunde et al, 2004) and root hair formation (Lombardo et al, 2006).…”