Nitric Oxide Mediates the Indole Acetic Acid Induction Activation of a Mitogen-Activated Protein Kinase Cascade Involved in Adventitious Root Development

Abstract

Recently, it was demonstrated that nitric oxide (NO) and cGMP are involved in the auxin response during the adventitious rooting process in cucumber (Cucumis sativus; Pagnussat et al., 2002Pagnussat et al., , 2003. However, not much is known about the complex molecular network operating during the cell proliferation and morphogenesis triggered by auxins and NO in that process. Anatomical studies showed that formation of adventitious root primordia was clearly detected in indole acetic acid (IAA)-and NO-treated cucumber explants, while neither cell proliferation nor differentiation into root primordia could be observed in control explants 3 d after primary root was removed. In order to go further with signal transduction mechanisms that operate during IAA-and NO-induced adventitious root formation, experiments were designed to test the involvement of a mitogenactivated protein kinase (MAPK) cascade in that process. Cucumber explants were treated with the NO-donor sodium nitroprusside (SNP) or with SNP plus the specific NO-scavenger cPTIO. Protein extracts from those explants were assayed for protein kinase (PK) activity by using myelin basic protein (MBP) as substrate in both in vitro and in-gel assays. The activation of a PK of approximately 48 kD could be detected 1 d after NO treatment with a maximal activation after 3 d of treatment. In control explants, a PK activity was detected only after 4 d of treatment. The MBP-kinase activity was also detected in extracts from IAA-treated explants, while no signal was observed in IAA 1 cPTIO treatments. The PK activity could be inhibited by the cell-permeable MAPK kinase inhibitor PD098059, suggesting that the NO-dependent MBP-kinase activity is a MAPK. Furthermore, when PD098059 was administered to explants treated with SNP or IAA, it produced a delay in root emergence and a dose-dependent reduction in root number. Altogether, our results suggest that a MAPK signaling cascade is activated during the adventitious rooting process induced by IAA in a NO-mediated but cGMP-independent pathway. The activation of MAPKs is discussed in relation to the cell responses modulating mitotic process.Auxins play a central role in numerous developmental processes functioning as a signal for cell division, elongation and differentiation. Among auxin actions, an indole acetic acid (IAA) dependence of root formation, apical dominance, and tropic responses have been described (Theologis, 1986;Estelle, 1992;Davies, 1995). The molecular basis of auxin action is an area of intense study. Genetic approaches to dissect how this hormone triggers a variety of effects in plants rely on the analysis of mutants modified in their response to auxin (Walden and Lubenow, 1996). The available mutants display an array of phenotypes that indicates changes in auxin action or response including altered growth, changes in root length and apical dominance, and reduced gravitropism (Lincoln et al., 1990;Pickett et al., 1990;Wilson et al., 1990;Hobbie and Estelle, 1995;Leyser et al., 1996).Adventitious root for...

S-Nitrosylation — another biological switch like phosphorylation?

“…Signal transduction mechanism operating during IAA and NO induced adventitious root formation shows the involvement of mitogen activated protein kinase (MAPK) cascade (Pagnussat et al, 2004). NO induced activation of MAPK is reported in tobacco (Kumar and Klessig, 2000) and Arabidopsis (Clarke et al, 2000).…”

N-3-Oxo-Decanoyl-l-Homoserine-Lactone Activates Auxin-Induced Adventitious Root Formation via Hydrogen Peroxide- and Nitric Oxide-Dependent Cyclic GMP Signaling in Mung Bean

“…Adventitious roots are derived primarily from plant stems and are essential for plant adaptation to environmental stress; studying the adventitious root formation is also significant for both fundamental and applied plant biology. The phytohormone auxin plays an essential role in stimulating adventitious root formation (Pagnussat et al, 2003(Pagnussat et al, , 2004. Significant progress has been made to elucidate the molecular mechanism of auxin action via the auxin/ indole-3-acetic acid (Aux/IAA) and auxin-response factor (ARF) gene families.…”

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

“…Through these chemical modifications of target proteins, NO may trigger changes in their activities and cellular functions, ultimately leading to the transduction of the NO message into plant responses. Synergistic effects of auxin and NO have been observed during the regulation of a series of plant responses, including the interplay between these molecules during adventitious roots formation (Pagnussat et al, 2004), lateral root development (CorreaAragunde et al, 2004) and root hair initiation and elongation (Lombardo et al, 2006). In virtually all of these cases, NO was identified to function downstream of auxins, apparently through linear signaling pathways.…”

“…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). Various nitric oxide donors such as Sodium nitroprusside (SNP), S-nitroso-N-acetylpenicillamine (SNAP) and Snitrosoglutathione (GSNO) have been developed (Mur et al, 2012) but SNP is frequently used (Correa-Aragunde et al, 2004;Mur et al, 2012;Chohan et al, 2012;Kong et al, 2014).…”