Immunolocalization of actin in root statocytes of Lens culinaris L

• Published in: Journal of experimental botany Vol. 51; no. 344; pp. 521 - 528
• Main Authors: Driss‐Ecole, D., Vassy, J., Rembur, J., Guivarc'h, A., Prouteau, M., Dewitte, W., Perbal, G.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-03-2000; OXFORD UNIVERSITY PRESS
• Subjects: 5‐bromo‐4‐chloro‐3‐indolyl phosphatase/nitroblue tetrazolium; Actin; Actins; Actins - chemistry; Actins - ultrastructure; Agronomy. Soil science and plant productions; Amyloplasts; Antibodies; Antibodies, Monoclonal; anti‐chicken gizzard actin IgG; BCIP/NBT; Biological and medical sciences; Biomedicals; Blocking buffer; bovine serum albumin; BSA; Cell and Molecular Biology, Biochemistry and Molecular Physiology; Cell Polarity; CRA; cress root actin antibody; Cytoplasm; cytoskeleton; Cytoskeleton - chemistry; Cytoskeleton - ultrastructure; dimethylsulphoxide; DMSO; Economic plant physiology; EDTA; EGTA; ethylenediaminetetraacetic acid; ethyleneglycol‐bis‐(β‐aminoethylether)‐N; Fabaceae - cytology; Fabaceae - ultrastructure; Fluorescent Dyes; Fundamental and applied biological sciences. Psychology; ICN; Immunoblotting; Immunohistochemistry; immunolocalization; lentil root; Lentils; MBS; Meckenheim/Germany; Microfilaments; Monoclonal antibodies; m‐maleimidobenzoyl N‐hydroxysuccinimide ester; NaN3; NBT; NGS; normal goat serum; N′‐bis(2‐ethane‐sulphonic acid); N′‐tetraacetic acid; Organelles; PBS; Phalloidine; phenylmethylsulfonyl fluoride; phosphate‐buffered saline; Physical agents; piperazine‐N; PIPES; Plant cells; Plant physiology and development; Plant roots; Plant Roots - cytology; Plant Roots - ultrastructure; Plants, Medicinal; PMSF; pre‐embedding technique; p‐nitroblue tetrazolium chloride; Rhodamines; sodium azide; statocyte; TBS; Tris‐buffered saline; Tropism and nastic movements; Vegetative apparatus, growth and morphogenesis. Senescence; Intracellular movement; Immunogold labelling; Cell organelle; Root; Microfilament; Lens culinaris; Electron microscopy; Orientation; Grain legume; Signal transduction; Leguminosae; Actin; Dicotyledones; Angiospermae; Distribution; Cytoskeleton; Gravitropism; Perception; Spermatophyta; Gravity
• DOI: 10.1093/jexbot/51.344.521
• EISSN: 1460-2431
• ISSN: 0022-0957; 1460-2431

Lentil root statocytes show a strict structural polarity of their organelles with respect to the g vector. These cells are involved in the perception of gravity and are responsible for the orientation of the root. Actin filaments take part in the positioning of their organelles and could also be involved in the transduction of the gravitropic signal. A pre‐embedding immunogold silver technique was carried out with a monoclonal antibody in order to study the distribution of actin cytoskeleton in the statocytes at the electron microscopic level. Some areas were never labelled (cell wall, vacuole, nucleoplasm, mitochondria, starch grains of the amyloplasts) or very slightly labelled (stroma of the amyloplasts). The labelling was scattered in the cytoplasm always close to, or on the nuclear and amyloplast envelopes and the tonoplast. Associations of 2 to 6 dots in file were observed, but these short files were not oriented in one preferential direction. They corresponded to a maximum distance of 0.9 μm. This work demonstrated that each statocyte organelle was enmeshed in an actin web of short filaments arranged in different ways. The images obtained by rhodamine‐phalloidin staining were in accordance with those of immunogold labelling. The diffuse fluorescence of the cytoplasm could be explained by the fact that the meshes of the web should be narrow. The vicinity of actin and of the amyloplasts envelope could account for the movement of these organelles that was observed in spatial microgravity.