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First published online January 27, 2006; 10.1104/pp.105.073825 Plant Physiology 140:879-889 (2006) © 2006 American Society of Plant Biologists Characterization of low phosphorus insensitive Mutants Reveals a Crosstalk between Low Phosphorus-Induced Determinate Root Development and the Activation of Genes Involved in the Adaptation of Arabidopsis to Phosphorus Deficiency1Departamento de Ingeniería Genética (L.S.-C., J.L.-B., A.C.-L., A.G.-O., E.H.-A.) and Laboratorio Nacional de Genómica (L.H.-E.), Centro de Investigación y de Estudios Avanzados, 36500 Irapuato, Guanajuato, Mexico
Low phosphorus (P) availability is one of the most limiting factors for plant productivity in many natural and agricultural ecosystems. Plants display a wide range of adaptive responses to cope with low P stress, which generally serve to enhance P availability in the soil and to increase its uptake by roots. In Arabidopsis (Arabidopsis thaliana), primary root growth inhibition and increased lateral root formation have been reported to occur in response to P limitation. To gain knowledge of the genetic mechanisms that regulate root architectural responses to P availability, we designed a screen for identifying Arabidopsis mutants that fail to arrest primary root growth when grown under low P conditions. Eleven low phosphorus insensitive (lpi) mutants that define at least four different complementation groups involved in primary root growth responses to P availability were identified. The lpi mutants do not show the typical determinate developmental program induced by P stress in the primary root. Other root developmental aspects of the low P rescue system, including increased root hair elongation and anthocyanin accumulation, remained unaltered in lpi mutants. In addition to the insensitivity of primary root growth inhibition, when subjected to P deprivation, lpi mutants show a reduced induction in the expression of several genes involved in the P starvation rescue system (PHOSPHATE TRANSPORTER 1 and 2, PURPLE ACID PHOSPHATASE 1, ACID PHOSPHATASE 5, and INDUCED BY PHOSPHATE STARVATION 1). Our results provide genetic support for the role of P as an important signal for postembryonic root development and root meristem maintenance and show a crosstalk in developmental and biochemical responses to P deprivation.
1 This work was supported by the Howard Hughes Medical Institute (grant no. Nbr55003677), Consejo Nacional de Ciencia y Tecnología (grant no. SEP2003C0243979), and the European Commission (grant no. ICA4CT200030017). 2 Present address: Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Edificio B3, Ciudad Universitaria, Morelia Michoacán, México. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Luis Herrera-Estrella (lherrera{at}ira.cinvestav.mx). Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.105.073825. * Corresponding author; e-mail lherrera{at}ira.cinvestav.mx; fax 52(462)6245846. Received November 7, 2005; returned for revision December 21, 2005; accepted December 26, 2005. This article has been cited by other articles:
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