Desiccation and osmotic stress increase the abundance of mRNA of the tonoplast aquaporin BobTIP26-1 in cauliflower cells

• Published in: Planta Vol. 209; no. 1; pp. 77 - 86
• Main Authors: Barrieu, François, Marty-Mazars, Danièle, Thomas, Dominique, Chaumont, François, Charbonnier, Maryse, Marty, Francis
• Format: Journal Article
• Language: English
• Published: Berlin Springer-Verlag 01.07.1999; Springer
• Subjects: Agronomy. Soil science and plant productions; Animals; Aquaporins; Aquaporins - genetics; Biological and medical sciences; biosynthesis; Brassica; Brassica - genetics; Brassica oleracea var. botrytis; Cauliflower; cell growth; Cell membranes; cell suspension culture; Cell walls; Complementary DNA; Dehydration; Economic plant physiology; flowers; Fundamental and applied biological sciences. Psychology; gene expression; genetics; Membrane Proteins; Membrane Proteins - genetics; meristems; Messenger RNA; nucleic acid hybridization; Oocytes; Osmosis; Plant physiology and development; plant proteins; Plant Proteins - genetics; RNA; RNA, Messenger; RNA, Messenger - biosynthesis; RNA, Plant; RNA, Plant - biosynthesis; shrinkage; Tonoplast; vacuoles; Water; Water and solutes. Absorption, translocation and permeability; Water relations, transpiration, stomata; water stress; Xenopus; Brassica oleracea var. botrytis; Tonoplast; Cytology; Gene expression; Vacuole; Water stress; Vegetable crop; Cruciferae; Water regime; Ultrastructure; Dicotyledones; Angiospermae; Spermatophyta; Aquaporin
• DOI: 10.1007/s004250050608
• ISSN: 0032-0935

Changes in vacuolar structure and the expression at the RNA level of a tonoplast aquaporin (BobTIP26-1) were examined in cauliflower (Brassica oleracea L. var. botrytis) under water-stress conditions. Gradual drying out of slices of cauliflower floret tissue caused its collapse, with a shrinkage in tissue and cell volumes and an apparent vesiculation of the central vacuole, whereas osmotic stress resulted in plasmolysis with a collapse of the cytoplasm and the central vacuole within. Osmotic stress caused a rapid and substantial increase in BobTIP26 mRNA in slices of floret tissue. Exposure of tissue slices to a regime of desiccation showed a slower but equally large rise in BobTIP26 mRNA followed by a rapid decline upon rehydration. In situ hybridization showed that BobTIP26-2 mRNA is expressed most highly in meristematic and expanding cells of the cauliflower florets and that desiccation strongly increased the expression in those cells and in differentiated cells near the xylem vessels. These data indicate that under water-deficit conditions, expression of the tonoplast aquaporin gene in cauliflower is subject to a precise regulation that can be correlated with important cytological changes in the cells.