Abstract
Legume plants have an ability to fix atmospheric nitrogen via symbiosis with soil microbes. The transport of various metabolites between legume plants and rhizobia plays central roles in the establishment and physiological function of the nodules. ATP-binding cassette proteins constitute one of the largest protein families in plants, and have various functions in planta. cDNA array analysis revealed several ABC transporter genes are strongly induced during nodulation, suggesting the involvement of ABC proteins in nodulation processes. We have carried out a genome-wide analysis of ABC proteins in Lotus japonicus, and identified 91 putative ABC proteins. In this study, we focused one gene, named LjPDR1 (LjABCG1), which was specifically up-regulated in nodule formation. The expression of LjPDR1 was strongly induced by methyl jasmonate, and LjPDR1 was shown to be localized at the plasma membrane. We have created transgenic RNAi plants and are currently evaluating the phenotypes of these plants.
