Abstract: The effect of ultraviolet-B (UV-B) radiation on plant growth, photosynthetic competence, nitrate content, and extractable activity of nitrate reductase (NR; EC 1.6.6.1) was evaluated in maize (Zea mays L.) seedlings during a 13 days growth period. The results showed that under our experimental conditions UV-B radiation decreased the O2 evolution rates and the sugar contents of maize leaves without affecting the chlorophyll content, the chloroplast ultrastructure or the plant weight. Furthermore, this treatment induced significant decreases of leaf and root NR activities and of nitrate content. In addition, the analysis of the transcript accumulation of genes encoding maize NR and of a gene encoding a maize 14-3-3 protein did not show significant differences between tissues of control and UV-B treated seedlings. Conversely, the activation state of NR was slightly lower in treated plants with respect to the control. Our results indicate that the effect of UV-B radiation on NR activity do not involve a transcriptional mechanism of regulation of the NR isoforms considered in this research, but may implicate its modulation at a post-transcriptional level or may require the involvement of the transcriptional regulation of some other NR isoform
Response of maize (Zea mays L.) nitrate reductase to UV-B radiation
QUAGGIOTTI, SILVIA;TRENTIN, ANNA RITA;DALLA VECCHIA, FRANCESCA;GHISI, ROSSELLA
2004
Abstract
Abstract: The effect of ultraviolet-B (UV-B) radiation on plant growth, photosynthetic competence, nitrate content, and extractable activity of nitrate reductase (NR; EC 1.6.6.1) was evaluated in maize (Zea mays L.) seedlings during a 13 days growth period. The results showed that under our experimental conditions UV-B radiation decreased the O2 evolution rates and the sugar contents of maize leaves without affecting the chlorophyll content, the chloroplast ultrastructure or the plant weight. Furthermore, this treatment induced significant decreases of leaf and root NR activities and of nitrate content. In addition, the analysis of the transcript accumulation of genes encoding maize NR and of a gene encoding a maize 14-3-3 protein did not show significant differences between tissues of control and UV-B treated seedlings. Conversely, the activation state of NR was slightly lower in treated plants with respect to the control. Our results indicate that the effect of UV-B radiation on NR activity do not involve a transcriptional mechanism of regulation of the NR isoforms considered in this research, but may implicate its modulation at a post-transcriptional level or may require the involvement of the transcriptional regulation of some other NR isoformPubblicazioni consigliate
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