LjABCB1, an ATP-binding cassette protein specifically induced in uninfected cells of Lotus japonicus nodules.
Legume plants develop root nodules through symbiosis with rhizobia, and fix atmospheric nitrogen in this symbiotic organ. Development of root nodules is regulated by many metabolites including phytohormones. Previously, we reported that auxin is strongly involved in the development of the nodule vascular bundle and lenticel formation on the nodules of Lotus japonicus. Here we show that an ATP-binding cassette (ABC) protein, LjABCB1, which is a homologue of Arabidopsis auxin transporter AtABCB4, is specifically expressed during nodulation of L. japonicus. A reporter gene analysis indicated that the expression of LjABCB1 was restricted to uninfected cells adjacent to infected cells in the nodule, while no expression was observed in shoot apical meristems or root tips, in which most auxin transporter genes are expressed. The auxin transport activity of LjABCB1 was confirmed using a heterologous expression system.
Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji 611-0011, Japan.
Kojiro
K
Takanashi
Akifumi
A
Sugiyama
Shusei
S
Sato
Satoshi
S
Tabata
Kazufumi
K
Yazaki
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis* / Q000235:genetics; D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D000070116:Lotus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D009586:Nitrogen Fixation / Q000235:genetics*; D010940:Plant Proteins / Q000096:biosynthesis* / Q000235:genetics; D012231:Rhizobium / Q000378:metabolism; D053204:Root Nodules, Plant / Q000254:growth & development / Q000378:metabolism*; D013559:Symbiosis
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D002352:Carrier Proteins; D010940:Plant Proteins