Effects of (+)-8',8',8'-trifluoroabscisic acid on alpha-amylase expression and sugar accumulation in rice cells

• Published in: Planta Vol. 205; no. 3; pp. 319 - 326
• Main Authors: Kashem, M.A, Hori, H, Itoh, K, Hayakawa, T, Todoroki, Y, Hirai, N, Ohigashi, H, Mitsui, T
• Format: Journal Article
• Language: English
• Published: Berlin Springer-Verlag 01.07.1998; Springer
• Subjects: abscisic acid; Abscisic Acid - analogs & derivatives; Abscisic Acid - pharmacology; Acetates; Agronomy. Soil science and plant productions; Aleurone layer; alpha-amylase; alpha-Amylases; alpha-Amylases - metabolism; analogs; analogs & derivatives; Antibodies; Biological and medical sciences; Carbohydrate Metabolism; cell suspension culture; Cells, Cultured; Chemical suspensions; drug effects; Economic plant physiology; embryo (plant); Embryos; endosperm; enzyme activity; Fundamental and applied biological sciences. Psychology; gene expression; genetic regulation; Germination; gibberellic acid; Gibberellins; Gibberellins - pharmacology; glucose; Hormones; inhibition; Metabolism; Net assimilation, photosynthesis, carbon metabolism. Photorespiration, respiration, fermentation (anoxia, hypoxia); nutrient uptake; Nutrition. Photosynthesis. Respiration. Metabolism; Oryza; Oryza - drug effects; Oryza - metabolism; Oryza - physiology; Oryza sativa; pharmacology; Photosynthesis, respiration. Anabolism, catabolism; physiology; Plant Growth Regulators; Plant Growth Regulators - pharmacology; Plant physiology and development; protein synthesis; Rice; scutellum; Secretion; Seeds; Seeds - metabolism; Seeds - physiology; sucrose; Sugars; transcription (genetics); Cell culture; Monocotyledones; Embryo; Transcription; Enzyme; Glucose; Gene expression; Metabolism; Cereal crop; Biological activity; Oryza sativa; Regulation(control); Gramineae; Glycosidases; Analog; Seed; Angiospermae; Abscisic acid; Hydrolases; Plant growth substance; Spermatophyta; α-Amylase; Biological accumulation; O-Glycosidases
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s004250050326

The effects of (+)-8',8',8'-trifluoroabscisic acid (trifluoro-ABA) on alpha-amylase expression were studied in rice embryoless half-seeds, scutella, and suspension-cultured cells derived from the embryo, and the effects of the analog on sugar accumulation were also studied in scutella and suspension-cultured cells. Treatment with (+)-trifluoro-ABA strongly inhibited the gibberellic acid-inducible expression of alpha-amylase I-1 encoded by RAmy1A in the aleurone layers of embryoless half-seeds at the levels of transcription, protein synthesis, and enzyme activity. It was also found that (+)-trifluoro-ABA stimulated (i) the uptake of glucose from the incubation medium and (ii) the synthesis of sucrose in scutellar tissues and suspension-cultured cells of rice. The biological activity of (+)-trifluoro-ABA was found to be more potent and persistent than that of natural ABA. We further examined the effects of trifluoro-ABA on the expression of alpha-amylase I-1 in scutellar tissues and suspension-cultured cells. It was found that (+)-trifluoro-ABA did not inhibit the formation of alpha-amylase I-1 in the absence of external glucose. However, glucose and (+)-trifluoro-ABA cooperatively suppressed the formation of alpha-amylase I-1. Judging from these results, we conclude that the regulatory mechanism for the expression of alpha-amylase I-1 in the scutellar epithelium is distinguishable from that operating in the aleurone layer.