Phosphate Availability Alters Architecture and Causes Changes in Hormone Sensitivity in the Arabidopsis Root System

• Published in: Plant physiology (Bethesda) Vol. 129; no. 1; pp. 244 - 256
• Main Authors: López-Bucio, José, Esmeralda Hernández-Abreu, Sánchez-Calderón, Lenin, María Fernanda Nieto-Jacobo, Simpson, June, Herrera-Estrella, Luis
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Biologists 01-05-2002; American Society of Plant Physiologists
• Subjects: 1-aminocyclopropane-1-carboxylic acid; 2,4-Dichlorophenoxyacetic Acid - pharmacology; Amino Acids, Cyclic - pharmacology; Arabidopsis; Arabidopsis - drug effects; Arabidopsis - genetics; Arabidopsis - growth & development; Architectural control; Architecture; Auxins; Biological and medical sciences; Biological Transport - physiology; Carboxylic acids; Chemical agents; Cytokinins - pharmacology; Dose-Response Relationship, Drug; Environmental conditions; Environmental Stress and Adaptation; Essential nutrients; Ethylenes - pharmacology; Fundamental and applied biological sciences. Psychology; Indoleacetic Acids - pharmacology; Mutation; Nutrient availability; Phosphates; Phosphates - pharmacology; Plant Growth Regulators - pharmacology; Plant physiology and development; Plant roots; Plant Roots - drug effects; Plant Roots - growth & development; Plant Shoots - drug effects; Plant Shoots - growth & development; Plants; Root growth; Root hairs; Root systems; Roots; Seedlings; Triiodobenzoic Acids - pharmacology; Vegetative apparatus, growth and morphogenesis. Senescence; Zeatin - pharmacology; Phosphates; Auxin; Growth; Available nutrient; Ethylene; Root hair; Rhizogenesis; Inorganic element; Arabidopsis thaliana; Cruciferae; Dicotyledones; Angiospermae; Plant growth substance; Nutrition; Root; Landrace(plant); Deficiency; Lateral; Genetic variant; Cytokinin; Plant architecture; Nutrient; Spermatophyta; Phytohormone; Mutation; Experimental plant
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.010934

The postembryonic developmental program of the plant root system is plastic and allows changes in root architecture to adapt to environmental conditions such as water and nutrient availability. Among essential nutrients, phosphorus (P) often limits plant productivity because of its low mobility in soil. Therefore, the architecture of the root system may determine the capacity of the plant to acquire this nutrient. We studied the effect of P availability on the development of the root system in Arabidopsis. We found that at P-limiting conditions (<50 μM), the Arabidopsis root system undergoes major architectural changes in terms of lateral root number, lateral root density, and primary root length. Treatment with auxins and auxin antagonists indicate that these changes are related to an increase in auxin sensitivity in the roots of P-deprived Arabidopsis seedlings. It was also found that the axr1-3, axr2-1, and axr4-1 Arabidopsis mutants have normal responses to low P availability conditions, whereas the iaa28-1 mutant shows resistance to the stimulatory effects of low P on root hair and lateral root formation. Analysis of ethylene signaling mutants and treatments with 1-aminocyclopropane-1-carboxylic acid showed that ethylene does not promote lateral root formation under P deprivation. These results suggest that in Arabidopsis, auxin sensitivity may play a fundamental role in the modifications of root architecture by P availability.