title: Characterization of AtSTOP1 orthologous genes in tobacco and other plant species.
abstract: Aluminum (Al) and proton (H⁺) tolerances are essential traits for plants to adapt to acid soil environments. In Arabidopsis (Arabidopsis thaliana), these tolerances are mediated by a zinc-finger transcription factor, SENSITIVE TO PROTON RHIZOTOXICITY1 (AtSTOP1), which regulates the transcription of multiple genes critical for tolerance to both stressors. Here, the functions of orthologous proteins (STOP1-like proteins) in other plant species were characterized by reverse genetics analyses and in planta complementation assays. RNA interference of a gene for NtSTOP1 repressed Al and H⁺ tolerances of tobacco (Nicotiana tabacum) roots. Tobacco roots released citrate in response to Al, concomitant with the up-regulated transcription of an ortholog of an Al tolerance gene encoding a citrate-transporting multidrug and toxic compound extrusion protein. The RNA interference repression of NtSTOP1 blocked this process and also repressed the transcription of another orthologous gene for Al tolerance, ALUMINUM SENSITIVE3, which encodes a prokaryote-type transporter. These results demonstrated that NtSTOP1 regulates Al tolerance in tobacco through the transcriptional regulation of these genes. The in planta complementation assays revealed that other plant species, including woody plants, a legume, and a moss (Physcomitrella patens), possess functional STOP1-like proteins that can activate several H⁺ and Al-tolerance genes in Arabidopsis. Knocking out the gene encoding the STOP1-like protein decreased the Al tolerance of P. patens. Together, our results strongly suggest that transcriptional regulation by STOP1-like proteins is evolutionarily conserved among land plants and that it confers the ability to survive in acid soils through the transcriptional regulation of Al- and H⁺-tolerance genes.
authors.affiliation: Plant Cell Technology, Faculty of Applied Biological Sciences, Gifu University, Gifu 501-1193, Japan.
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Ohyama
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ito
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Ikka
authors.forename: Akio
authors.initials: A
authors.lastname: Morita
authors.forename: Masatomo
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Ryujiro
authors.initials: R
authors.lastname: Imaizumi
authors.forename: Toshio
authors.initials: T
authors.lastname: Aoki
authors.forename: Kenji
authors.initials: K
authors.lastname: Komatsu
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Sakata
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iuchi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Koyama
mesh_terms: D000535:Aluminum / Q000633:toxicity; D000595:Amino Acid Sequence; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D019068:Bryopsida / Q000235:genetics / Q000254:growth & development; D002951:Citrates / Q000378:metabolism; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D018527:Hydroponics; D008293:Malates / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D034622:RNA Interference; D012987:Soil; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D016335:Zinc Fingers / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D002951:Citrates; D008293:Malates; D010940:Plant Proteins; C525886:STOP1 protein, Arabidopsis; D012987:Soil; D014157:Transcription Factors; D000535:Aluminum