Knockout of a bacterial-type ATP-binding cassette transporter gene, AtSTAR1, results in increased aluminum sensitivity in Arabidopsis.
ATP-binding cassette (ABC) transporters represent a large family in plants, but the functions of most of these transporters are unknown. Here we report a gene, AtSTAR1, only encoding an ATP-binding domain of a bacterial-type ABC transporter in Arabidopsis (Arabidopsis thaliana). AtSTAR1 is an ortholog of rice (Oryza sativa) OsSTAR1, which has been implicated in aluminum (Al) tolerance. Knockout of AtSTAR1 resulted in increased sensitivity to Al and earlier flowering. Unlike OsSTAR1, AtSTAR1 was expressed in both the roots and shoots and its expression was not induced by Al or other stresses. Investigation of tissue-specific localization of AtSTAR1 through beta-glucuronidase fusion revealed that AtSTAR1 was predominantly expressed at outer cell layers of root tips and developing leaves, whose localization is also different from those of OsSTAR1. However, introduction of OsSTAR1 into atstar1 mutant rescued the sensitivity of atstar1 to Al, indicating that AtSTAR1 has a similar function as OsSTAR1. Furthermore, we found that AtSTAR1 may interact with ALS3, a transmembrane-binding domain in Arabidopsis to form a complex because introduction of OsSTAR1, a functional substitute of AtSTAR1, into als3 mutant resulted in the loss of OsSTAR1 protein. All these findings indicate that AtSTAR1 is involved in the basic detoxification of Al in Arabidopsis.
Huang
Chao-Feng
CF
Institute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, Japan.
Yamaji
Naoki
N
Ma
Jian Feng
JF
D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000535:Aluminum / Q000494:pharmacology*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009154:Mutation; D018515:Plant Leaves / Q000378:metabolism; D018517:Plant Roots / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics
D018528:ATP-Binding Cassette Transporters; D029681:Arabidopsis Proteins; D018749:RNA, Plant; D000535:Aluminum