Cyclic ADP-ribose and ABA signal transduction

Abstract

A new assay system utilizing ABA-inducible gene expression in tomato hypocotyl cells has placed cADPR firmly in the signal transduction cascade of this hormone[1xAbscisic acid signaling through cyclic ADP-ribose in plants. Wu, Y. et al. Science. 1997; 278: 2126–2130Crossref | PubMed | Scopus (273)See all References][1]. Furthermore, similar transduction pathways utilizing cADPR appear to be activated regardless of whether the cellular response to ABA is gene expression or stomatal closure (Fig. 2Fig. 2). Striking similarities are evident between cADPR action in plant and animal cells.Fig. 2Schematic representation of ABA signal-transduction pathways that involve cyclic ADP-ribose (cADPR) and result in gene expression in tomato hypocotyl cells or loss of guard cell turgor. The upper part shows ABA perception and transduction in tomato hypocotyls, resulting in gene expression mediated by cADPR and elevation of cytosolic Ca2+ concentration[1xAbscisic acid signaling through cyclic ADP-ribose in plants. Wu, Y. et al. Science. 1997; 278: 2126–2130Crossref | PubMed | Scopus (273)See all References][1]. The lower part shows ABA perception and transduction in guard cells, resulting in loss of cell turgor mediated by cADPR and elevation of cytosolic Ca2+ concentration.View Large Image | Download PowerPoint Slide