Heterologous Expression of Chimeric Repressor of Arabidopsis ANAC046 Delays Chlorophyll Degradation in Petunia Flowers

摘要

We have previously found that a transcription factor, ANAC046, acts as a positive regulator of chlorophyll degradation and senescence in Arabidopsis leaves. In this study, we introduced overexpression (OX) or dominant negative (SRDX) constructs into petunia (Petunia hybrida) with a focus on the effect of the introduced gene on the flowers. The corolla limbs of the OX plants showed enhanced levels of chlorophyll catabolic genes resulting in lower chlorophyll content than those of wild-type plants. In the SRDX plants, chlorophyll catabolic genes were down-regulated and a higher level of chlorophyll was accumulated in the corolla limbs. There was no significant difference in the expression levels of senescence-associated genes and flower longevity between wild-type and transgenic plants. In petunia leaves, ANAC046 promoted chlorophyll degradation and senescence as previously observed in Arabidopsis leaves. We conclude that common or closely related transcription factors that regulate chlorophyll degradation may exist in the leaves and flowers, whereas those involved in senescence are different between them.