Signaling in plants

Abstract

This paper serves as a summary of a symposium session as part of the Frontiers of Science series, held November 7-9, 1996, at the Arnold and Mabel Beckman Center of the National Academies of Sciences and Engineering in Irvine, CA. Signaling in plants ABSTRACTHigher plants are sessile organisms that perceive environmental cues such as light and chemical signals and respond by changing their morphologies. Signaling pathways utilize a complex network of interactions to orchestrate biochemical and physiological responses such as f lowering, fruit ripening, germination, photosynthetic regulation, and shoot or root development. In this session, the mechanisms of signaling systems that trigger plant responses to light and to the gaseous hormone, ethylene, were discussed. These signals are first sensed by a receptor and transmitted to the nucleus by a complex network. A signal may be transmitted to the nucleus by any of several systems including GTP binding proteins (G proteins), which change activity upon GTP binding; protein kinase cascades, which sequentially phosphorylate and activate a series of proteins; and membrane ion channels, which change ionic characteristics of the cells. The signal is manifested in the nucleus as a change in the activity of DNA-binding proteins, which are transcription factors that specifically interact and modulate the regulatory regions of genes. Thus, detection of an environmental signal is transmitted through a transduction pathway, and changes in transcription factor activity may coordinate changes in the expression of a portfolio of genes to direct new developmental programs.

Action potentials in abscisic acid-deficient tomato mutant generated spontaneously and evoked by electrical stimulation

“…In the twentieth century, after the discovery of plant hormones (Audus 1959), the scientists turned their attention to these substances such as auxin, gibberellins, abscisic acid, ethylene, cytokinins, brassinosteroids, salicylic acid, and jasmonic acid (Davies 2010). With the advent of molecular biology, the understanding of the mechanisms of cell-cell and organ-organ communication by phytohormones, peptides, nucleotides, fatty acids, reactive oxygen species, and others, has been improved; evidencing chemical signals as having a major role in signaling processes (Mulligan et al 1997;Apel and Hirt 2014;Kushwah and Laxmi 2014;Sanchita et al 2014).…”

A Mutation in the Arabidopsis HYL1 Gene Encoding a dsRNA Binding Protein Affects Responses to Abscisic Acid, Auxin, and Cytokinin

“…The implication is that individual proteins can be responsible for such interconnections, either transmitting multiple signals or participating in distinct complexes that transmit different signals (Elion, 1998). Proteins can receive information from a small molecule, such as a hormone, and transmit it to a macromolecule, such as another protein, commonly through either a covalent modification, such as phosphorylation, or protein binding (Mulligan et al, 1997;Trewavas and Malho, 1997;Moller and Chua, 1999;Nambara and McCourt, 1999). Proteins can also receive and transmit information at the macromolecular level through protein-protein interactions, phosphorylation or other structural modifications, and protein-nucleic acid interactions.…”

“…Hormones have long been known to be important internal mediating signals in plants, but the components of the underlying cellular machinery are just beginning to be identified and characterized (Trewavas and Malho, 1997; Grill and Himmelbach, 1998;Solano and Ecker, 1998;D'Agostino and Kieber, 1999). The range of proteins involved in receiving, transmitting, and responding to external signals includes receptorlike and other kinds of protein kinases, phosphatases, and transcription factors, as well as enzymes such as thioredoxin and farnesyltransferase, which influence protein structure or localization through mechanisms other than phosphorylation (Mulligan et al, 1997; Becraft, 1998;Bonetta and McCourt, 1998; Hooley, 1998;Bleecker, 1999;Thornton et al, 1999; Hirt, 2000;Urao et al, 2000).…”

“…Hormones have long been known to be important internal mediating signals in plants, but the components of the underlying cellular machinery are just beginning to be identified and characterized (Trewavas and Malho, 1997; Grill and Himmelbach, 1998;Solano and Ecker, 1998;D'Agostino and Kieber, 1999). The range of proteins involved in receiving, transmitting, and responding to external signals includes receptorlike and other kinds of protein kinases, phosphatases, and transcription factors, as well as enzymes such as thioredoxin and farnesyltransferase, which influence protein structure or localization through mechanisms other than phosphorylation (Mulligan et al, 1997; Becraft, 1998;Bonetta and McCourt, 1998; Hooley, 1998;Bleecker, 1999;Thornton et al, 1999; Hirt, 2000;Urao et al, 2000).Ample physiological evidence supports the presence of interconnections among plant responses to different environmental stimuli; moreover, evidence is accumulating that certain mutations can simultaneously influence the response to more than one hormone or altered physical parameter (Wilson et al, 1990;Clouse et al, 1996;Nemeth et al, 1998;Ephritikhine et al, 1999a; Beaudoin et al, 2000; Ghassemian et al, 2000). The implication is that individual proteins can be responsible for such interconnections, either transmitting multiple signals or participating in distinct complexes that transmit different signals (Elion, 1998).…”

Regulation of the Dual Specificity Protein Phosphatase, DsPTP1, through Interactions with Calmodulin

“…In most cases, the active form of CaM (Ca 2ϩ -bound) regulates the activity and function of a wide range of CaM-binding proteins (CaMBP), including metabolic enzymes, transcription factors, ion channels, protein kinases/phosphatases, and structural proteins (10,11). Therefore, CaM acts as a multifunctional protein in Ca 2ϩ -mediated signal transduction networks and regulates the activities of proteins that are structurally distinct and opposite proteins, such as protein phosphorylation and dephosphorylation (12)(13)(14).…”