Anthocyanin accumulation and related gene expression in Japanese parsley (Oenanthe stolonifera, DC.) induced by low temperature

Low temperature was found to induce the accumulation of anthocyanins in Jap anese parsley (Oenanthe stolonifera, DC.), and cyanidin was identified as t heir major component. Among three cultivars, cv. Jizeri responded most stro ngly to low-temperature stress, accumulating four-fold higher anthocyanin l evels in leaves of plants grown at 12 degreesC compared with those at 25 de greesC. RNA gel-blot analysis showed that expression of the dihydroflavonol 4-reductase gene (dir) was especially affected by low temperature. In the cv. Jizeri, the dfr transcripts were rapidly induced 6 to 7 days after tran sfer to low-temperature conditions, whereas dir expression was scarcely obs erved in the non-pigmented cultivar (cv. Matsuemidori). The phenylalanine a mmonia-lyase gene (pal) and chalcone synthase gene (chs) seemed to be expre ssed coordinately at both 12 degreesC and 25 degreesC in both cultivars. Th e pal and chs genes comprised multigene families, while the dir gene was de tected as being unique. These results suggest that the mechanism regulating dfr expression differs from those for pal and chs expression in Japanese p arsley, and that dir expression is a key step in the regulation by low-temp erature stress in the temperature-sensitive cultivars of Japanese parsley.