Abstract
Legume plants establish nitrogen-fixing nodules with rhizobia in a species-specific manner. During the nodulation process and symbiotic nitrogen fixation (SNF), a large variety of metabolites are exchanged between plant cells and rhizobia via membrane transport. ATP binding-cassette (ABC) proteins, which constitute the largest transporter family in plants, may play important roles in these processes, and indeed several members of ABC protein gene are strongly expressed with different induction patterns during the nodulation formation.
Tissue specific expression study was done with real time PCR analysis to demonstrate that several members of the full-length ABCG subfamily are strongly up-regulated by rhizobial infection. cDNA array analysis during nodulation (Kouchi et al., DNA Research, 11: 263-274, 2004) suggested that one gene chr3.CM0026.74, which was designated as LjABCG1, was most prominently up-regulated in the early stage of infection.
