24.ストレス応答花成とフェニルアラニンアンモニアリアーゼで制御される代謝系(口頭発表)

概要

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A short-day plant (SDP), Pharbitis nil can be induced to flower by responding to poor nutrition stress under long days (LD). This LD flowering was inhibited by a phenylalanine ammonia-lyase (PAL) inhibitor and the inhibition was overcome by salicylic acid (SA). Exogenously applied SA did not induce to flower under non-stress condition. The treatment of P. nil with SA plus a DNA demethylating reagent, 5-azacytidine induced flowering, although the flowering response was weaker than that induced by the stress. This stress-induced flowering may be induced by SA, DNA demethylation and some other factor(s). Another SDP, Perilla frutescens, can be also induced to flower by low-light intensity stress under LD. This flowering was also inhibited by a PAL inhibitor. Thus, the metabolic pathway regulated by PAL, possibly that related to SA, may be involved in the regulation of stress-induced flowering in the both species. But, the effects of stresses on anthocyanine synthesis which is regulated by PAL were opposite between them. The expressions of PAL and other gene involved in the anthocyanine synthesis were analyzed in P. frutescens. PAL expression was suppressed by low-intensity light, and CHALCONE SYNTHASE (CHS) expression was not changed by light intensity. These results do not support the hypothesis that PAL-regulated SA synthesis is promoted to induce flowering under low-intensity light.
2008-10-06