Zinc finger protein STOP1 is critical for proton tolerance in Arabidopsis and coregulates a key gene in aluminum tolerance

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 104; no. 23; pp. 9900 - 9905
• Main Authors: Iuchi, Satoshi, Koyama, Hiroyuki, Iuchi, Atsuko, Kobayashi, Yasufumi, Kitabayashi, Sadako, Kobayashi, Yuriko, Ikka, Takashi, Hirayama, Takashi, Shinozaki, Kazuo, Kobayashi, Masatomo
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 05-06-2007; National Acad Sciences
• Subjects: Acid soils; acidity; Aluminum; Aluminum - toxicity; Amino Acid Sequence; Arabidopsis; Arabidopsis - drug effects; Arabidopsis - genetics; Arabidopsis - growth & development; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Base Sequence; Biological Sciences; Botany; Cloning, Molecular; Computational Biology; Disease; DNA Primers; Gene Components; Gene Expression Regulation, Plant - genetics; Genes; Genetic Complementation Test; Genetic mutation; Hydroponics; Hypersensitivity; Malates - metabolism; metal tolerance; missense mutation; Molecular Sequence Data; mutants; Mutation, Missense - genetics; nucleotide sequences; Organic Anion Transporters - metabolism; phenotype; phytotoxicity; plant proteins; Plant Roots - drug effects; Plant Roots - genetics; Plant Roots - metabolism; Plants; Proteins; Protons; Reverse Transcriptase Polymerase Chain Reaction; Root growth; roots; Seedlings; Sequence Alignment; Sequence Analysis, DNA; signal transduction; STOP1 gene; STOP1 protein; stress tolerance; transcription factors; Transcription Factors - genetics; Zinc; zinc finger motif; zinc finger proteins; Zinc Fingers
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0700117104

Acid soil syndrome causes severe yield losses in various crop plants because of the rhizotoxicities of ions, such as aluminum (Al³⁺). Although protons (H⁺) could be also major rhizotoxicants in some soil types, molecular mechanisms of their tolerance have not been identified yet. One mutant that was hypersensitive to H⁺ rhizotoxicity was isolated from ethyl methanesulfonate mutagenized seeds, and a single recessive mutation was found on chromosome 1. Positional cloning followed by genomic sequence analysis revealed that a missense mutation in the zinc finger domain in a predicted Cys₂His₂-type zinc finger protein, namely sensitive to proton rhizotoxicity (STOP)1, is the cause of hypersensitivity to H⁺ rhizotoxicity. The STOP1 protein belongs to a functionally unidentified subfamily of zinc finger proteins, which consists of two members in Arabidopsis based on a Blast search. The stop1 mutation resulted in no effects on cadmium, copper, lanthanum, manganese and sodium chloride sensitivitities, whereas it caused hypersensitivity to Al³⁺ rhizotoxicity. This stop1 mutant lacked the induction of the AtALMT1 gene encoding a malate transporter, which is concomitant with Al-induced malate exudation. There was no induction of AtALMT1 by Al³⁺ treatment in the stop1 mutant. These results indicate that STOP1 plays a critical role in Arabidopsis tolerance to major stress factors in acid soils.