Abstract
More than 30 unknown trans-membrane proteins putatively act as transporters of metabolites across the tonoplast membrane. However, actual functions of these trans-membrane proteins have not been clarified yet. We are currently investigating functions of several unknown tonoplast trans-membrane proteins, and mechanisms with which they control cellular and vacuolar metabolisms. In this study, we report changes observed in metabolite profiles of transgenic lines of Arabidopsis plants that overexpress a gene encoding a putative vacuolar transporter protein (At3g21690). In rosette leaves of the transgenic plants, significant increase was observed in the accumulation of glucosinolates and isothiocyanates. These glucosinolates were also detected in the vacuole isolated from wild-type Arabidopsis leaves. The results suggested that the At3g21690 protein transports glucosinolate to vacuole in Arabidopsis leaves. To test this hypothesis, we are currently producing T87 cultured cell line that overexpresses both At3g21690 gene and Myb28 gene that encodes a transcription factor regulating glucosinolate biosynthesis. This work was partly supported by CREST, JST.
