Zinc finger protein STOP1 is critical for proton tolerance in Arabidopsis and coregulates a key gene in aluminum tolerance.
Acid soil syndrome causes severe yield losses in various crop plants because of the rhizotoxicities of ions, such as aluminum (Al(3+)). 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 Cys(2)His(2)-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 Al(3+) 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 Al(3+) treatment in the stop1 mutant. These results indicate that STOP1 plays a critical role in Arabidopsis tolerance to major stress factors in acid soils.
Iuchi
Satoshi
S
BioResources Center, RIKEN, 3-1-1 Koyadai, Tsukuba, Ibaraki 305-0074, Japan. iuchi@brc.riken.jp
Koyama
Hiroyuki
H
Iuchi
Atsuko
A
Kobayashi
Yasufumi
Y
Kitabayashi
Sadako
S
Kobayashi
Yuriko
Y
Ikka
Takashi
T
Hirayama
Takashi
T
Shinozaki
Kazuo
K
Kobayashi
Masatomo
M
D000535:Aluminum / Q000633:toxicity*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D019295:Computational Biology; D017931:DNA Primers; D040461:Gene Components; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D005816:Genetic Complementation Test; D008293:Malates / Q000378:metabolism; D008969:Molecular Sequence Data; D020125:Mutation, Missense / Q000235:genetics; D027361:Organic Anion Transporters / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D011522:Protons; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics*; D016335:Zinc Fingers
C512361:ALMT1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D017931:DNA Primers; D008293:Malates; D027361:Organic Anion Transporters; D011522:Protons; C525886:STOP1 protein, Arabidopsis; D014157:Transcription Factors; C030298:malic acid; D000535:Aluminum