Involvement of phosphoinositide turnover in tracheary element differentiation in Zinnia elegans L. cells

• Published in: Planta 2002-06, Vol.215 (2), p.312-318
• Main Authors: Zhang, Xianchao G., Coté, Gary G., Crain, Richard C.
• Format: Article
• Language: English
• Subjects: Asteraceae - cytology; Asteraceae - drug effects; Asteraceae - metabolism; Biological and medical sciences; Calcium - pharmacology; Cell culture techniques; Cell differentiation; Cell Differentiation - drug effects; Cell Differentiation - physiology; Cell physiology; Cell walls; Cultured cells; Estrenes - pharmacology; Fundamental and applied biological sciences. Psychology; Inositol 1,4,5-Trisphosphate - analogs & derivatives; Inositol 1,4,5-Trisphosphate - antagonists & inhibitors; Inositol 1,4,5-Trisphosphate - biosynthesis; Inositols; Mesophyll cells; Pertussis Toxin; Phosphatidylinositols - metabolism; Plant cells; Plant physiology and development; Plant Structures - cytology; Plant Structures - drug effects; Plant Structures - metabolism; Plants; Pyrrolidinones - pharmacology; Toxins; Tracheary elements; Type C Phospholipases - metabolism; Virulence Factors, Bordetella - pharmacology; Whooping cough
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-002-0739-z

Mesophyll cells of Zinnia elegans L., cultured in the presence of phytohormones, will transdifferentiate and undergo programmed cell death to become tracheary elements, thick-walled cells of the xylem. This system is a model system for study of plant cell development and differentiation. We report that a high concentration of extracellular Ca2+ is necessary during the first 6 h of culturing for tracheary elements to form. Extracellular Ca2+ is still required at later times, but at a much lower concentration. When cells transdifferentiate in adequate Ca2+, microsomal phospholipase C activity increases and levels of inositol 1,4,5-trisphosphate rise at about hour 4 of culturing. The production of inositol 1,4,5-trisphosphate appears to be important for tracheary element formation, since inhibitors of phospholipase C inhibit both inositol 1,4,5-trisphosphate production and tracheary element formation. Pertussis toxin, an inhibitor of GTP-binding proteins, inhibits transdifferentiation and eliminates inositol 1,4,5-trisphosphate production. Tracheary element formation was not completely abolished by inhibitors that eliminated inositol 1,4,5-trisphosphate production, suggesting the involvement of other pathways in regulating transdifferentiation.