Anthocyanins are flavonoid pigments that accumulate in the large central vacuole of most plants. Inside the vacuole, anthocyanins can be found uniformly distributed or as part of sub-vacuolar pigment bodies, the Antho...Anthocyanins are flavonoid pigments that accumulate in the large central vacuole of most plants. Inside the vacuole, anthocyanins can be found uniformly distributed or as part of sub-vacuolar pigment bodies, the Anthocyanic Vacuolar Inclusions （AVIs）. Using Arabidopsis seedlings grown under anthocyanin-inductive conditions as a model to un- derstand how AVIs are formed, we show here that the accumulation of AVIs strongly correlates with the formation of cyanidin 3-glucoside （C3G） and derivatives. Arabidopsis mutants that fail to glycosylate anthocyanidins at the 5-0 position （Sgt mutant） accumulate AVIs in almost every epidermal cell of the cotyledons, as compared to wild-type seedlings, where only a small fraction of the cells show AVIs. A similar phenomenon is observed when seedlings are treated with vanadate. Highlighting a role for autophagy in the formation of the AVIs, we show that various mutants that interfere with the autophagic process （atg mutants） display lower numbers of AVIs, in addition to a reduced accumulation of anthocyanins. Interestingly, vanadate increases the numbers of AVIs in the atg mutants, suggesting that several pathways might participate in AVl formation. Taken together, our results suggest novel mechanisms for the formation of sub-vacuolar compartments capable of accumulating anthocyanin pigments.展开更多
The translation of the genotype into phenotype, represented for example by the expression of genes encod- ing enzymes required for the biosynthesis of phytochemicals that are important for interaction of plants with t...The translation of the genotype into phenotype, represented for example by the expression of genes encod- ing enzymes required for the biosynthesis of phytochemicals that are important for interaction of plants with the environment, is largely carried out by transcription factors （TFs） that recognize specific cis-regulatory elements in the genes that they control. TFs and their target genes are organized in gene regulatory net- works （GRNs）, and thus uncovering GRN architecture presents an important biological challenge necessary to explain gene regulation. Linking TFs to the genes they control, central to understanding GRNs, can be car- ried out using gene- or TF-centered approaches. In this study, we employed a gene-centered approach uti- lizing the yeast one-hybrid assay to generate a network of protein-DNA interactions that participate in the transcriptional control of genes involved in the biosynthesis of maize phenolic compounds including gen- eral phenylpropanoids, lignins, and flavonoids. We identified 1100 protein-DNA interactions involving 54 phenolic gene promoters and 568 TFs. A set of 11 TFs recognized 10 or more promoters, suggesting a role in coordinating pathway gene expression. The integration of the gene-centered network with informa- tion derived from TF-centered approaches provides a foundation for a phenolics GRN characterized by in- terlaced feed-forward loops that link developmental regulators with biosynthetic genes.展开更多
Dear Editor, Flavonols are synthesized by flavonol synthase （FLS） enzymes （Martens et al., 2010）. These compounds absorb UV-B light in the 280-320-nm region and their concentration increases in plants exposed to ...Dear Editor, Flavonols are synthesized by flavonol synthase （FLS） enzymes （Martens et al., 2010）. These compounds absorb UV-B light in the 280-320-nm region and their concentration increases in plants exposed to environmental abiotic and biotic stresses, including UV-B; consequently, flavonols are thought to act as UV-B filters （Agati et al., 2011）. It has been also suggested that these metabolites function as reactive oxygen species （ROS） scavengers, as they contain an OH- group in the 3-position of the flavonoid skeleton, which allows them to chelate metals, inhibiting the formation of free radicals and ROS accumula- tion, once formed （Agati et al., 2009）. For these reasons, it has been suggested that flavonols play uncharacterized roles in UV responses （Verdan et al., 2011）. Nevertheless, despite the fact that the role of flavonols in UV-B protection has been inferred, the protection conferred by flavonols on the target sites of UV-B-damage has not been directly proven in planta.展开更多
文摘Anthocyanins are flavonoid pigments that accumulate in the large central vacuole of most plants. Inside the vacuole, anthocyanins can be found uniformly distributed or as part of sub-vacuolar pigment bodies, the Anthocyanic Vacuolar Inclusions （AVIs）. Using Arabidopsis seedlings grown under anthocyanin-inductive conditions as a model to un- derstand how AVIs are formed, we show here that the accumulation of AVIs strongly correlates with the formation of cyanidin 3-glucoside （C3G） and derivatives. Arabidopsis mutants that fail to glycosylate anthocyanidins at the 5-0 position （Sgt mutant） accumulate AVIs in almost every epidermal cell of the cotyledons, as compared to wild-type seedlings, where only a small fraction of the cells show AVIs. A similar phenomenon is observed when seedlings are treated with vanadate. Highlighting a role for autophagy in the formation of the AVIs, we show that various mutants that interfere with the autophagic process （atg mutants） display lower numbers of AVIs, in addition to a reduced accumulation of anthocyanins. Interestingly, vanadate increases the numbers of AVIs in the atg mutants, suggesting that several pathways might participate in AVl formation. Taken together, our results suggest novel mechanisms for the formation of sub-vacuolar compartments capable of accumulating anthocyanin pigments.
文摘The translation of the genotype into phenotype, represented for example by the expression of genes encod- ing enzymes required for the biosynthesis of phytochemicals that are important for interaction of plants with the environment, is largely carried out by transcription factors （TFs） that recognize specific cis-regulatory elements in the genes that they control. TFs and their target genes are organized in gene regulatory net- works （GRNs）, and thus uncovering GRN architecture presents an important biological challenge necessary to explain gene regulation. Linking TFs to the genes they control, central to understanding GRNs, can be car- ried out using gene- or TF-centered approaches. In this study, we employed a gene-centered approach uti- lizing the yeast one-hybrid assay to generate a network of protein-DNA interactions that participate in the transcriptional control of genes involved in the biosynthesis of maize phenolic compounds including gen- eral phenylpropanoids, lignins, and flavonoids. We identified 1100 protein-DNA interactions involving 54 phenolic gene promoters and 568 TFs. A set of 11 TFs recognized 10 or more promoters, suggesting a role in coordinating pathway gene expression. The integration of the gene-centered network with informa- tion derived from TF-centered approaches provides a foundation for a phenolics GRN characterized by in- terlaced feed-forward loops that link developmental regulators with biosynthetic genes.
文摘Dear Editor, Flavonols are synthesized by flavonol synthase （FLS） enzymes （Martens et al., 2010）. These compounds absorb UV-B light in the 280-320-nm region and their concentration increases in plants exposed to environmental abiotic and biotic stresses, including UV-B; consequently, flavonols are thought to act as UV-B filters （Agati et al., 2011）. It has been also suggested that these metabolites function as reactive oxygen species （ROS） scavengers, as they contain an OH- group in the 3-position of the flavonoid skeleton, which allows them to chelate metals, inhibiting the formation of free radicals and ROS accumula- tion, once formed （Agati et al., 2009）. For these reasons, it has been suggested that flavonols play uncharacterized roles in UV responses （Verdan et al., 2011）. Nevertheless, despite the fact that the role of flavonols in UV-B protection has been inferred, the protection conferred by flavonols on the target sites of UV-B-damage has not been directly proven in planta.
