Abstract
ABC (ATP-Binding Cassette) proteins constitute a large superfamily found in bacteria, fungi, plants and animals. cDNA array analysis of Lotus japonicus during nodulation was recently reported, in which we found one PDR (Pleiotropic Drug Resistance)-type ABC protein (LjPDR12) gene that shows up-regulation during the early stage of nodulation. LjPDR12 shares amino acid identity of 68%, 70% and 65% to AtPDR12, NpABC1 and SpTUR2, respectively.
We then treated L. japonicus seedlings with various chemicals including plant hormones. The expression of LjPDR12 was strongly increased by methyl jasmonate (MeJA). Detailed time-course analysis showed that the increment of the expression reached to ca. 10-fold from 3 to 48 hours after the treatment. Salicylic acid also increased the mRNA level of LjPDR12 up to 10-fold after 3 hours but the up-regulation was transient. In contrast, absisic acid suppressed the gene expression of LjPDR12. We are preparing RNAi plants to provide phenotype analyses.
