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Anton R Schaffner - One of the best experts on this subject based on the ideXlab platform.
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kaempferol 3 o rhamnoside 7 o rhamnoside is an endogenous Flavonol inhibitor of polar auxin transport in arabidopsis shoots
New Phytologist, 2014Co-Authors: Werner Heller, Andreas Albert, Petre I Dobrev, Eva Zažimalova, Anton R SchaffnerAbstract:Polar auxin transport (PAT) plays key roles in the regulation of plant growth and development. Flavonoids have been implicated in the inhibition of PAT. However, the active flavonoid Derivative(s) involved in this process in vivo has not yet been identified. Here, we provide evidence that a specific Flavonol bis-glycoside is correlated with shorter plant stature and reduced PAT. Specific flavonoid-biosynthetic or flavonoid-glycosylating steps were genetically blocked in Arabidopsis thaliana. The differential Flavonol patterns established were analyzed by high-performance liquid chromatography (HPLC) and related to altered plant stature. PAT was monitored in stem segments using a radioactive [3H]-indole-3-acetic acid tracer. The flavonoid 3-O-glucosyltransferase mutant ugt78d2 exhibited a dwarf stature in addition to its altered Flavonol glycoside pattern. This was accompanied by reduced PAT in ugt78d2 shoots. The ugt78d2-dependent growth defects were flavonoid dependent, as they were rescued by genetic blocking of flavonoid biosynthesis. Phenotypic and metabolic analyses of a series of mutants defective at various steps of flavonoid formation narrowed down the potentially active moiety to kaempferol 3-O-rhamnoside-7-O-rhamnoside. Moreover, the level of this compound was negatively correlated with basipetal auxin transport. These results indicate that kaempferol 3-O-rhamnoside-7-O-rhamnoside acts as an endogenous PAT inhibitor in Arabidopsis shoots. Keywords: Arabidopsis thaliana, Flavonol biosynthesis, Flavonol glycoside, Flavonol glycosyltransferases, plant growth, polar auxin transport Introduction The phytohormone auxin, represented predominantly by indole-3-acetic acid (IAA), plays a crucial role in plant growth and development. Auxin needs to be transported from the sites of synthesis, mainly in the apices and young leaves, to the distal part of the plant to exert its function (Berleth et al., 2007). Auxin transporters, including ABCB proteins, AUX1/LAX family members and PIN proteins (Noh et al., 2001; Friml, 2003; Petrasek et al., 2006; Yang et al., 2006; Zažimalova et al., 2010; Peer et al., 2011), are responsible for the auxin fluxes and patterning in plants (Friml et al., 2003). Flavonoids, phenylpropanoic secondary metabolites, have been implicated in the blocking of auxin transport (Peer & Murphy, 2007). The supply of Flavonols to detached zucchini hypocotyls resulted in decreased polar auxin transport (PAT) (Jacobs & Rubery, 1988). In Arabidopsis, PAT was increased in transparent testa4 (tt4), a flavonoid-deficient mutant defective in the first step of flavonoid production (Shirley et al., 1995; Buer & Muday, 2004; Peer et al., 2004) (Fig.(Fig.1).1). Accordingly, tt4 roots exhibited delayed gravitropism, which was reversed by chemical complementation by naringenin, an intermediate of flavonoid biosynthesis (Buer & Muday, 2004). By contrast, PAT was reduced in the Flavonol over-production mutant tt3 defective in dihydroFlavonol reductase (Fig.(Fig.1),1), consistent with an inhibitory role of Flavonols in PAT (Peer et al., 2004). Despite these and other substantial pieces of evidence supporting a role of Flavonols in the modulation of auxin transport (Kuhn et al., 2011; Lewis et al., 2011; Grunewald et al., 2012), neither specific Flavonol aglycones nor their conjugates active in this process in vivo have been identified so far. Figure 1 Flavonoid biosynthesis pathway in Arabidopsis thaliana. (a) Scheme of flavonoid biosynthesis. CHS (TT4), chalcone synthase; F3′H (TT7), flavonoid 3′-hydroxylase; DFR (TT3), dihydroFlavonol 4-reductase; FLS, Flavonol synthase; ANS (TT18), ... The difficulty in relating specific Flavonols to auxin transport modulation is, in part, a result of the complex Flavonol modification in planta. Flavonol aglycones are intensively modified by UDP-dependent glycosyltransferases (UGTs), which include UGT78D1, UGT78D2, UGT78D3, UGT73C6 and UGT89C1 in the model plant Arabidopsis thaliana (Fig.(Fig.1)1) (Jones et al., 2003; Tohge et al., 2005; Yonekura-Sakakibara et al., 2007, 2008). The glycosides are distributed in an organ-specific manner. In contrast with the complex Flavonol profile in flowers, it is rather simple in inflorescence stems (Yonekura-Sakakibara et al., 2008; Stracke et al., 2010b). Thus, the inflorescence stem, which is implicated in basipetal auxin movement, is the optimal organ for searching for the Flavonol Derivative(s) active in auxin transport modulation. Here, we show that the loss of the flavonoid 3-O-glucosyltransferase UGT78D2 resulted in an altered Flavonol glycoside pattern and reduced PAT in shoots, which was accompanied by a reduced plant height and increased branching. Blocking of flavonoid biosynthesis and/or glycosylation at specific steps clearly related the enhanced accumulation of kaempferol 3-O-rhamnoside-7-O-rhamnoside (k1) to the growth defects of ugt78d2. Through analyses of auxin transport in several genotypes, which contained different levels of k1, an inverse correlation between basipetal auxin transport and k1 level was identified. Therefore, we propose that k1 acts as an endogenous auxin transport inhibitor in Arabidopsis shoots.
Erdem Yesilada - One of the best experts on this subject based on the ideXlab platform.
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bioassay guided isolation of kaempferol 3 o β d galactoside with anti inflammatory and antinociceptive activity from the aerial part of calluna vulgaris l
Journal of Ethnopharmacology, 2007Co-Authors: Ilkay Erdogan Orhan, Esra Kupeli, S Terzioglu, Erdem YesiladaAbstract:Calluna vulgaris L. (Ericaceae) is used for the treatment of various inflammatory ailments in traditional medicines. In order to evaluate this ethnobotanical information, its anti-inflammatory and antinociceptive activities were studied using in vivo experimental models in mice. The ethanolic extract of the plant was first fractionated into five extracts; namely, n-hexane, chloroform, ethyl acetate (EtOAc), n-butanol, and water fractions. Among them, the EtOAc Fr. was found to be the most effective and was further subjected to bioassay-guided fractionation and isolation procedures. After successive column chromatography applications, on Sephadex LH-20 and silica gel, a component, which is responsible for the above-mentioned activities of this species of Turkish origin, was isolated and its structure was elucidated as kaempferol-3-O-β-d-galactoside, a common Flavonol Derivative by means of spectral techniques.
Werner Heller - One of the best experts on this subject based on the ideXlab platform.
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kaempferol 3 o rhamnoside 7 o rhamnoside is an endogenous Flavonol inhibitor of polar auxin transport in arabidopsis shoots
New Phytologist, 2014Co-Authors: Werner Heller, Andreas Albert, Petre I Dobrev, Eva Zažimalova, Anton R SchaffnerAbstract:Polar auxin transport (PAT) plays key roles in the regulation of plant growth and development. Flavonoids have been implicated in the inhibition of PAT. However, the active flavonoid Derivative(s) involved in this process in vivo has not yet been identified. Here, we provide evidence that a specific Flavonol bis-glycoside is correlated with shorter plant stature and reduced PAT. Specific flavonoid-biosynthetic or flavonoid-glycosylating steps were genetically blocked in Arabidopsis thaliana. The differential Flavonol patterns established were analyzed by high-performance liquid chromatography (HPLC) and related to altered plant stature. PAT was monitored in stem segments using a radioactive [3H]-indole-3-acetic acid tracer. The flavonoid 3-O-glucosyltransferase mutant ugt78d2 exhibited a dwarf stature in addition to its altered Flavonol glycoside pattern. This was accompanied by reduced PAT in ugt78d2 shoots. The ugt78d2-dependent growth defects were flavonoid dependent, as they were rescued by genetic blocking of flavonoid biosynthesis. Phenotypic and metabolic analyses of a series of mutants defective at various steps of flavonoid formation narrowed down the potentially active moiety to kaempferol 3-O-rhamnoside-7-O-rhamnoside. Moreover, the level of this compound was negatively correlated with basipetal auxin transport. These results indicate that kaempferol 3-O-rhamnoside-7-O-rhamnoside acts as an endogenous PAT inhibitor in Arabidopsis shoots. Keywords: Arabidopsis thaliana, Flavonol biosynthesis, Flavonol glycoside, Flavonol glycosyltransferases, plant growth, polar auxin transport Introduction The phytohormone auxin, represented predominantly by indole-3-acetic acid (IAA), plays a crucial role in plant growth and development. Auxin needs to be transported from the sites of synthesis, mainly in the apices and young leaves, to the distal part of the plant to exert its function (Berleth et al., 2007). Auxin transporters, including ABCB proteins, AUX1/LAX family members and PIN proteins (Noh et al., 2001; Friml, 2003; Petrasek et al., 2006; Yang et al., 2006; Zažimalova et al., 2010; Peer et al., 2011), are responsible for the auxin fluxes and patterning in plants (Friml et al., 2003). Flavonoids, phenylpropanoic secondary metabolites, have been implicated in the blocking of auxin transport (Peer & Murphy, 2007). The supply of Flavonols to detached zucchini hypocotyls resulted in decreased polar auxin transport (PAT) (Jacobs & Rubery, 1988). In Arabidopsis, PAT was increased in transparent testa4 (tt4), a flavonoid-deficient mutant defective in the first step of flavonoid production (Shirley et al., 1995; Buer & Muday, 2004; Peer et al., 2004) (Fig.(Fig.1).1). Accordingly, tt4 roots exhibited delayed gravitropism, which was reversed by chemical complementation by naringenin, an intermediate of flavonoid biosynthesis (Buer & Muday, 2004). By contrast, PAT was reduced in the Flavonol over-production mutant tt3 defective in dihydroFlavonol reductase (Fig.(Fig.1),1), consistent with an inhibitory role of Flavonols in PAT (Peer et al., 2004). Despite these and other substantial pieces of evidence supporting a role of Flavonols in the modulation of auxin transport (Kuhn et al., 2011; Lewis et al., 2011; Grunewald et al., 2012), neither specific Flavonol aglycones nor their conjugates active in this process in vivo have been identified so far. Figure 1 Flavonoid biosynthesis pathway in Arabidopsis thaliana. (a) Scheme of flavonoid biosynthesis. CHS (TT4), chalcone synthase; F3′H (TT7), flavonoid 3′-hydroxylase; DFR (TT3), dihydroFlavonol 4-reductase; FLS, Flavonol synthase; ANS (TT18), ... The difficulty in relating specific Flavonols to auxin transport modulation is, in part, a result of the complex Flavonol modification in planta. Flavonol aglycones are intensively modified by UDP-dependent glycosyltransferases (UGTs), which include UGT78D1, UGT78D2, UGT78D3, UGT73C6 and UGT89C1 in the model plant Arabidopsis thaliana (Fig.(Fig.1)1) (Jones et al., 2003; Tohge et al., 2005; Yonekura-Sakakibara et al., 2007, 2008). The glycosides are distributed in an organ-specific manner. In contrast with the complex Flavonol profile in flowers, it is rather simple in inflorescence stems (Yonekura-Sakakibara et al., 2008; Stracke et al., 2010b). Thus, the inflorescence stem, which is implicated in basipetal auxin movement, is the optimal organ for searching for the Flavonol Derivative(s) active in auxin transport modulation. Here, we show that the loss of the flavonoid 3-O-glucosyltransferase UGT78D2 resulted in an altered Flavonol glycoside pattern and reduced PAT in shoots, which was accompanied by a reduced plant height and increased branching. Blocking of flavonoid biosynthesis and/or glycosylation at specific steps clearly related the enhanced accumulation of kaempferol 3-O-rhamnoside-7-O-rhamnoside (k1) to the growth defects of ugt78d2. Through analyses of auxin transport in several genotypes, which contained different levels of k1, an inverse correlation between basipetal auxin transport and k1 level was identified. Therefore, we propose that k1 acts as an endogenous auxin transport inhibitor in Arabidopsis shoots.
Ilkay Erdogan Orhan - One of the best experts on this subject based on the ideXlab platform.
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bioassay guided isolation of kaempferol 3 o β d galactoside with anti inflammatory and antinociceptive activity from the aerial part of calluna vulgaris l
Journal of Ethnopharmacology, 2007Co-Authors: Ilkay Erdogan Orhan, Esra Kupeli, S Terzioglu, Erdem YesiladaAbstract:Calluna vulgaris L. (Ericaceae) is used for the treatment of various inflammatory ailments in traditional medicines. In order to evaluate this ethnobotanical information, its anti-inflammatory and antinociceptive activities were studied using in vivo experimental models in mice. The ethanolic extract of the plant was first fractionated into five extracts; namely, n-hexane, chloroform, ethyl acetate (EtOAc), n-butanol, and water fractions. Among them, the EtOAc Fr. was found to be the most effective and was further subjected to bioassay-guided fractionation and isolation procedures. After successive column chromatography applications, on Sephadex LH-20 and silica gel, a component, which is responsible for the above-mentioned activities of this species of Turkish origin, was isolated and its structure was elucidated as kaempferol-3-O-β-d-galactoside, a common Flavonol Derivative by means of spectral techniques.
Andreas Albert - One of the best experts on this subject based on the ideXlab platform.
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kaempferol 3 o rhamnoside 7 o rhamnoside is an endogenous Flavonol inhibitor of polar auxin transport in arabidopsis shoots
New Phytologist, 2014Co-Authors: Werner Heller, Andreas Albert, Petre I Dobrev, Eva Zažimalova, Anton R SchaffnerAbstract:Polar auxin transport (PAT) plays key roles in the regulation of plant growth and development. Flavonoids have been implicated in the inhibition of PAT. However, the active flavonoid Derivative(s) involved in this process in vivo has not yet been identified. Here, we provide evidence that a specific Flavonol bis-glycoside is correlated with shorter plant stature and reduced PAT. Specific flavonoid-biosynthetic or flavonoid-glycosylating steps were genetically blocked in Arabidopsis thaliana. The differential Flavonol patterns established were analyzed by high-performance liquid chromatography (HPLC) and related to altered plant stature. PAT was monitored in stem segments using a radioactive [3H]-indole-3-acetic acid tracer. The flavonoid 3-O-glucosyltransferase mutant ugt78d2 exhibited a dwarf stature in addition to its altered Flavonol glycoside pattern. This was accompanied by reduced PAT in ugt78d2 shoots. The ugt78d2-dependent growth defects were flavonoid dependent, as they were rescued by genetic blocking of flavonoid biosynthesis. Phenotypic and metabolic analyses of a series of mutants defective at various steps of flavonoid formation narrowed down the potentially active moiety to kaempferol 3-O-rhamnoside-7-O-rhamnoside. Moreover, the level of this compound was negatively correlated with basipetal auxin transport. These results indicate that kaempferol 3-O-rhamnoside-7-O-rhamnoside acts as an endogenous PAT inhibitor in Arabidopsis shoots. Keywords: Arabidopsis thaliana, Flavonol biosynthesis, Flavonol glycoside, Flavonol glycosyltransferases, plant growth, polar auxin transport Introduction The phytohormone auxin, represented predominantly by indole-3-acetic acid (IAA), plays a crucial role in plant growth and development. Auxin needs to be transported from the sites of synthesis, mainly in the apices and young leaves, to the distal part of the plant to exert its function (Berleth et al., 2007). Auxin transporters, including ABCB proteins, AUX1/LAX family members and PIN proteins (Noh et al., 2001; Friml, 2003; Petrasek et al., 2006; Yang et al., 2006; Zažimalova et al., 2010; Peer et al., 2011), are responsible for the auxin fluxes and patterning in plants (Friml et al., 2003). Flavonoids, phenylpropanoic secondary metabolites, have been implicated in the blocking of auxin transport (Peer & Murphy, 2007). The supply of Flavonols to detached zucchini hypocotyls resulted in decreased polar auxin transport (PAT) (Jacobs & Rubery, 1988). In Arabidopsis, PAT was increased in transparent testa4 (tt4), a flavonoid-deficient mutant defective in the first step of flavonoid production (Shirley et al., 1995; Buer & Muday, 2004; Peer et al., 2004) (Fig.(Fig.1).1). Accordingly, tt4 roots exhibited delayed gravitropism, which was reversed by chemical complementation by naringenin, an intermediate of flavonoid biosynthesis (Buer & Muday, 2004). By contrast, PAT was reduced in the Flavonol over-production mutant tt3 defective in dihydroFlavonol reductase (Fig.(Fig.1),1), consistent with an inhibitory role of Flavonols in PAT (Peer et al., 2004). Despite these and other substantial pieces of evidence supporting a role of Flavonols in the modulation of auxin transport (Kuhn et al., 2011; Lewis et al., 2011; Grunewald et al., 2012), neither specific Flavonol aglycones nor their conjugates active in this process in vivo have been identified so far. Figure 1 Flavonoid biosynthesis pathway in Arabidopsis thaliana. (a) Scheme of flavonoid biosynthesis. CHS (TT4), chalcone synthase; F3′H (TT7), flavonoid 3′-hydroxylase; DFR (TT3), dihydroFlavonol 4-reductase; FLS, Flavonol synthase; ANS (TT18), ... The difficulty in relating specific Flavonols to auxin transport modulation is, in part, a result of the complex Flavonol modification in planta. Flavonol aglycones are intensively modified by UDP-dependent glycosyltransferases (UGTs), which include UGT78D1, UGT78D2, UGT78D3, UGT73C6 and UGT89C1 in the model plant Arabidopsis thaliana (Fig.(Fig.1)1) (Jones et al., 2003; Tohge et al., 2005; Yonekura-Sakakibara et al., 2007, 2008). The glycosides are distributed in an organ-specific manner. In contrast with the complex Flavonol profile in flowers, it is rather simple in inflorescence stems (Yonekura-Sakakibara et al., 2008; Stracke et al., 2010b). Thus, the inflorescence stem, which is implicated in basipetal auxin movement, is the optimal organ for searching for the Flavonol Derivative(s) active in auxin transport modulation. Here, we show that the loss of the flavonoid 3-O-glucosyltransferase UGT78D2 resulted in an altered Flavonol glycoside pattern and reduced PAT in shoots, which was accompanied by a reduced plant height and increased branching. Blocking of flavonoid biosynthesis and/or glycosylation at specific steps clearly related the enhanced accumulation of kaempferol 3-O-rhamnoside-7-O-rhamnoside (k1) to the growth defects of ugt78d2. Through analyses of auxin transport in several genotypes, which contained different levels of k1, an inverse correlation between basipetal auxin transport and k1 level was identified. Therefore, we propose that k1 acts as an endogenous auxin transport inhibitor in Arabidopsis shoots.