Malate-dependent Fe accumulation is a critical checkpoint in the root developmental response to low phosphate

Low phosphate (Pi) availability constrains plant development and seed production in both natural and agricultural ecosystems. When Pi is scarce, modifications of root system architecture (RSA) enhance the soil exploration ability of the plant and lead to an increase in Pi uptake. In Arabidopsis, an...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2017-04, Vol.114 (17), p.E3563-E3572
Main Authors: Mora-Macías, Javier, Ojeda-Rivera, Jonathan Odilón, Gutiérrez-Alanís, Dolores, Yong-Villalobos, Lenin, Oropeza-Aburto, Araceli, Raya-González, Javier, Jiménez-Domínguez, Gabriel, Chávez-Calvillo, Gabriela, Rellán-Álvarez, Rubén, Herrera-Estrella, Luis
Format: Article
Language:English
Subjects:
Accumulation
Agricultural ecosystems
Aluminum
Apoplast
Arabidopsis
Availability
Biological Sciences
Cell differentiation
Cells
Computer architecture
Deprivation
Differentiation (biology)
Exploration
Exudation
Flowers & plants
Genes
Genomics
Genotype & phenotype
Iron
Malate
Media
Mutants
Phenotypes
Phosphates
PNAS Plus
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Summary:Low phosphate (Pi) availability constrains plant development and seed production in both natural and agricultural ecosystems. When Pi is scarce, modifications of root system architecture (RSA) enhance the soil exploration ability of the plant and lead to an increase in Pi uptake. In Arabidopsis, an iron-dependent mechanism reprograms primary root growth in response to low Pi availability. This program is activated upon contact of the root tip with low-Pi media and induces premature cell differentiation and the arrest of mitotic activity in the root apical meristem, resulting in a short-root phenotype. However, the mechanisms that regulate the primary root response to Pilimiting conditions remain largely unknown. Here we report on the isolation and characterization of two low-Pi insensitive mutants (lpi5 and lpi6), which have a long-root phenotype when grown in low-Pi media. Cellular, genomic, and transcriptomic analysis of low-Pi insensitive mutants revealed that the genes previously shown to underlie Arabidopsis Al tolerance via root malate exudation, known as SENSITIVE TO PROTON RHIZOTOXICITY (STOP1) and ALUMINUM ACTIVATED MALATE TRANSPORTER 1 (ALMT1), represent a critical checkpoint in the root developmental response to Pi starvation in Arabidopsis thaliana. Our results also show that exogenous malate can rescue the long-root phenotype of lpi5 and lpi6. Malate exudation is required for the accumulation of Fe in the apoplast of meristematic cells, triggering the differentiation of meristematic cells in response to Pi deprivation.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.1701952114