Showing papers on "Phytoalexin published in 2010"
TL;DR: The OsMKK4–OsMPK6 cascade plays a crucial role in reprogramming plant metabolism during MAMP-triggered defense responses and induces dynamic changes of metabolic flow from glycolysis to secondary metabolite biosynthesis while suppressing basic cellular activities.
Abstract: Plants recognize potential microbial pathogens through microbial-associated molecular patterns (MAMPs) and activate a series of defense responses, including cell death and the production of reactive oxygen species (ROS) and diverse anti-microbial secondary metabolites. Mitogen-activated protein kinase (MAPK) cascades are known to play a pivotal role in mediating MAMP signals; however, the signaling pathway from a MAPK cascade to the activation of defense responses is poorly understood. Here, we found in rice that the chitin elicitor, a fungal MAMP, activates two rice MAPKs (OsMPK3 and OsMPK6) and one MAPK kinase (OsMKK4). OsMPK6 was essential for the chitin elicitor-induced biosynthesis of diterpenoid phytoalexins. Conditional expression of the active form of OsMKK4 (OsMKK4(DD) ) induced extensive alterations in gene expression, which implied dynamic changes of metabolic flow from glycolysis to secondary metabolite biosynthesis while suppressing basic cellular activities such as translation and cell division. OsMKK4(DD) also induced various defense responses, such as cell death, biosynthesis of diterpenoid phytoalexins and lignin but not generation of extracellular ROS. OsMKK4(DD) -induced cell death and expression of diterpenoid phytoalexin pathway genes, but not that of phenylpropanoid pathway genes, were dependent on OsMPK6. Collectively, the OsMKK4-OsMPK6 cascade plays a crucial role in reprogramming plant metabolism during MAMP-triggered defense responses.
200 citations
TL;DR: It is verified that resveratrol has antibacterial activity against all tested Gram-positive bacteria using both the disk diffusion and broth microdilution methods and indicates that this compound may have potential as a natural antibacterial agent for both food preservation and medicinal use.
Abstract: Resveratrol (3,4′,5-trihydroxistilbene) is a phytoalexin commonly found in food and drinks, which is thought to possess antimicrobial activity. These effects together with its well known antioxidant properties are beneficial for the prevention of some diseases, e.g. cancer. In this study we have verified that resveratrol has antibacterial activity against all tested Gram-positive bacteria using both the disk diffusion and broth microdilution methods. Time kill assays of this compound against Gram-positive bacteria showed that its effects on the growth of bacterial cells were due to bacteriostatic action. The addition of resveratrol has allowed the identification of changes in cell morphology and DNA contents, which have been assessed through microscopic analysis and flow cytometry; this suggests that the cell cycle is affected by resveratrol. This study indicates that this compound may have potential as a natural antibacterial agent for both food preservation and medicinal use.
186 citations
TL;DR: The presence of SA, pyochelin, and/or pyoverdin in priming phytoalexin responses and induced grapevine resistance by 7NSK2 against B. cinerea suggests the production of bacterial compounds serving as inducers of disease resistance.
Abstract: Non-pathogenic rhizobacteria Pseudomonas spp. can reduce disease in plant tissues through induction of a defence state known as induced systemic resistance (ISR). This resistance is based on multiple bacterial determinants, but nothing is known about the mechanisms underlying rhizobacteria-induced resistance in grapevine. In this study, the ability of Pseudomonas fluorescens CHA0 and Pseudomonas aeruginosa 7NSK2 to induce resistance in grapevine against Botrytis cinerea is demonstrated. Both strains also triggered an oxidative burst and phytoalexin (i.e. resveratrol and viniferin) accumulation in grape cells and primed leaves for accelerated phytoalexin production upon challenge with B. cinerea. Treatment of cell cultures with crude cell extracts of bacteria strongly enhanced oxidative burst, but resulted in comparable amounts of phytoalexins and resistance to B. cinerea to those induced by living bacteria. This suggests the production of bacterial compounds serving as inducers of disease resistance. Using other strains with different characteristics, it is shown that P. fluorescens WCS417 (Pch-deficient), P. putida WCS358 (Pch- and SA-deficient) and P. fluorescens Q2-87 (a DAPG producer) were all capable of inducing resistance to an extent similar to that induced by CHA0. However, in response to WCS417 (Pch-negative) the amount of H2O2 induced is less than for the CHA0. WCS417 induced low phytoalexin levels in cells and lost the capacity to prime for phytoalexins in the leaves. This suggests that, depending on the strain, SA, pyochelin, and DAPG are potentially effective in inducing or priming defence responses. The 7NSK2 mutants, KMPCH (Pch- and Pvd-negative) and KMPCH-567 (Pch-, Pvd-, and SA-negative) induced only partial resistance to B. cinerea. However, the amount of H2O2 triggered by KMPCH and KMPCH-567 was similar to that induced by 7NSK2. Both mutants also led to a low level of phytoalexins in grapevine cells, while KMPCH slightly primed grapevine leaves for enhanced phytoalexins. This highlights the importance of SA, pyochelin, and/or pyoverdin in priming phytoalexin responses and induced grapevine resistance by 7NSK2 against B. cinerea.
171 citations
TL;DR: Results indicate that HR-associated rapid PA biosynthesis induces severe restriction of fungus, allowing higher PA accumulation in resistant rice, while in susceptible rice, failure of PA accumulation at the early infection stage allows fungal growth.
Abstract: Blast fungus-induced accumulations of major rice diterpene phytoalexins (PA), momilactones A and B, and phytocassanes A through E were studied, focusing on their biosynthesis and detoxification. In resistant rice, all PA started to accumulate at 2 days postinoculation (dpi), at which hypersensitive reaction (HR)-specific small lesions became visible and increased 500- to 1,000-fold at 4 dpi, while the accumulation was delayed and several times lower in susceptible rice. Expression of PA biosynthetic genes was transiently induced at 2 dpi only in resistant plants, while it was highly induced in both plants at 4 dpi. Fungal growth was severely suppressed in resistant plants by 2 dpi but considerably increased at 3 to 4 dpi in susceptible plants. Momilactone A treatment suppressed fungal growth in planta and in vitro, and the fungus detoxified the PA in vitro. These results indicate that HR-associated rapid PA biosynthesis induces severe restriction of fungus, allowing higher PA accumulation in resistant rice, while in susceptible rice, failure of PA accumulation at the early infection stage allows fungal growth. Detoxification of PA would be a tactic of fungus to invade the host plant, and prompt induction of PA biosynthesis upon HR would be a trait of resistant rice to restrict blast fungus.
159 citations
TL;DR: Analysis with virus-induced gene silencing suggested that resistance of N. benthamiana against hemibiotrophic P. infestans requires both SA-regulated appropriate induction of cell death and ET-induced production of phytoalexin.
Abstract: Phytophthora infestans, the agent of late blight disease of potato, is a hemibiotrophic pathogen with biotrophic action during early infection and necrotrophic in the later stage of colonization. Mature Nicotiana benthamiana was resistant to P. infestans, whereas relatively young plants were susceptible to this pathogen. Young plants became resistant following a pretreatment with acibenzolar-S-methyl, a functional analog of salicylic acid (SA), indicating that susceptibility of young plants is due to a lack of induction of SA signaling. Further analysis with virus-induced gene silencing indicated that NbICS1 and NbEIN2, the genes for SA biosynthesis and ethylene (ET) signaling, respectively, are required for the resistance of mature N. benthamiana against P. infestans. Furthermore, these genes are required for the production of reactive oxygen species (ROS) induced by treatment of the INF1 elicitor. In NbICS1-silenced plants, cell death induced by either INF1 or necrosis-inducing protein NPP1.1 was significantly accelerated. Expression of genes for phytoalexin (capsidiol) biosynthesis, NbEAS and NbEAH, were regulated by ET, and gene silencing of either of them compromised resistance of N. benthamiana to P. infestans. Together, these results suggest that resistance of N. benthamiana against hemibiotrophic P. infestans requires both SA-regulated appropriate induction of cell death and ET-induced production of phytoalexin.
106 citations
TL;DR: The data suggest that resveratrol is able to provide functional protection of renal tubular cells, at least in part, by directly scavenging the RNS peroxynitrite.
95 citations
TL;DR: SbFNSII appears to share a similar catalytic mechanism with the licorice and Medicago truncatula FNSIIs (CYP93B subfamily) by converting flavanones to flavone through the formation of 2-hydroxyflavanones.
Abstract: Following inoculation with the anthracnose pathogen Colletotrichum sublineolum, seedlings of the sorghum resistant cultivar SC748-5 showed more rapid and elevated accumulation of luteolin than the susceptible cultivar BTx623. On the other hand, apigenin was the major flavone detected in infected BTx623 seedlings. Luteolin was demonstrated to show stronger inhibition of spore germination of C. sublineolum than apigenin. Because of their pathogen-inducible and antifungal nature, both flavone aglycones are considered sorghum phytoalexins. The key enzyme responsible for flavone biosynthesis has not been characterized in monocots. A sorghum pathogen-inducible gene encoding a cytochrome P450 protein (CYP93G3) in the uncharacterized CYP93G subfamily was identified. Transgenic expression of the P450 gene in Arabidopsis demonstrated that the encoded protein is a functional flavone synthase (FNS) II in planta. The sorghum gene was then termed SbFNSII. It is a single-copy gene located on chromosome 2 and the first FNSII gene characterized in a monocot. Metabolite analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in precursor ion scan mode revealed the accumulation of 2-hydroxynaringenin and 2-hydroxyeriodictyol hexosides in the transgenic Arabidopsis plants. Hence, SbFNSII appears to share a similar catalytic mechanism with the licorice and Medicago truncatula FNSIIs (CYP93B subfamily) by converting flavanones to flavone through the formation of 2-hydroxyflavanones.
92 citations
TL;DR: It is revealed that 3-deoxyanthocyanidin accumulation and SbDFR3 expression were induced by methyl jasmonate treatment in sorghum roots but the stimulation effects were antagonized by salicylic acid.
Abstract: 3-Deoxyanthocyanidins are the unique phytoalexins synthesized by sorghum in response to fungal inoculation. They are structurally related to anthocyanins but the final steps of their pathogen-inducible biosynthesis are not fully understood. We have identified new flavonoid structural genes from the recently completed sorghum BTx623 genome sequence. The biochemical functions of the different expressed sorghum genes were established in planta by complementation in the appropriate Arabidopsis transparent testa mutants. There is a family of nine chalcone synthase genes which are all inducible by fungal inoculation in sorghum seedlings. Specific dihydroflavonol 4-reductase (DFR) genes responsive to conditions which stimulated anthocyanin accumulation (SbDFR1) or 3-deoxyanthocyanidin production (SbDFR3) were identified. Recombinant SbDFR1 and SbDFR3 were found to function as typical DFRs by accepting dihydroflavonol substrates. On the other hand, both DFRs showed substantially lower but detectable NADPH-dependent activities toward flavanones. Reduction of flavanones to flavan-4-ols is a reaction step required for 3-deoxyanthocyanidin production. Flavanone 3-hydroxylase (F3H) converts flavanones to dihydroflavonols for anthocyanin biosynthesis. In sorghum seedlings, expression of two F3H genes was either absent or strongly suppressed during the accumulation of 3-deoxyanthocyanidins. Under such conditions, most flavanones are expected to be reduced by the pathogen-induced SbDFR3 for the formation of flavan-4-ols. Our work also revealed that 3-deoxyanthocyanidin accumulation and SbDFR3 expression were induced by methyl jasmonate treatment in sorghum roots but the stimulation effects were antagonized by salicylic acid.
60 citations
TL;DR: Two new prenylated stilbene dimers named arahypin-6 and arahYPin-7 have been isolated from wounded peanut seeds challenged by an Aspergillus caelatus strain and may play a defensive role against invasive fungi.
Abstract: The peanut plant can resist fungal attacks by producing stilbene-derived phytoalexins. Once understood, such a natural phytoalexin-based mechanism of peanut resistance could be potentially manipulated to obtain fungal-resistant peanut breeding lines. Several simple stilbenoid phytoalexins from peanuts have been reported. However, more complex stilbenoid derivatives such as those that have been reported from other sources and considered important factors in plant defense have not been found in peanuts. The purpose of this research was to isolate and characterize further new oligomeric peanut stilbenoids that may act as phytoalexins. Two new prenylated stilbene dimers named arahypin-6 (3) and arahypin-7 (4) have been isolated from wounded peanut seeds challenged by an Aspergillus caelatus strain. The structures of these new putative phytoalexins were determined by analysis of NMR, MS, and UV spectroscopic data. Together with other known peanut stilbenoids that were also produced in the challenged seeds, these new compounds may play a defensive role against invasive fungi.
41 citations
TL;DR: The virulence phenotype of the cell-wall mutant Bcchs3a on the model plant Arabidopsis thaliana is described and a critical role is assigned to the BcCHS3a chitin synthase isoform, both in fungal virulence and plant defense response.
Abstract: The fungal cell wall is a dynamic structure that protects the cell from different environmental stresses suggesting that wall synthesizing enzymes are of great importance for fungal virulence Previously, we reported the isolation and characterization of a mutant in class III chitin synthase, Bcchs3a, in the phytopathogenic fungus Botrytis cinerea We demonstrated that virulence of this mutant is severely impaired Here, we describe the virulence phenotype of the cell-wall mutant Bcchs3a on the model plant Arabidopsis thaliana and analyze its virulence properties, using a variety of A thaliana mutants We found that mutant Bcchs3a is virulent on pad2 and pad3 mutant leaves defective in camalexin Mutant Bcchs3a was not more susceptible towards camalexin than the wild-type strain but induced phytoalexin accumulation at the infection site on Col-0 plants Moreover, this increase in camalexin was correlated with overexpression of the PAD3 gene observed as early as 18 h postinoculation The infection process of the mutant mycelium was always delayed by 48 h, even on pad3 plants, probably because of lack of mycelium adhesion No loss in virulence was found when Bcchs3a conidia were used as the inoculum source Collectively, these data led us to assign a critical role to the BcCHS3a chitin synthase isoform, both in fungal virulence and plant defense response
27 citations
TL;DR: The production of the major diterpenoid phytoalexins, momilactones and phytocassanes, was found to be induced by cytokinin treatment in both suspension-cultured rice cells and rice leaves, and also the upregulation of phy toalexin biosynthetic genes wasFindings suggest that cytokinins plays a key role in the production of diterPenoidphytoalxins in rice infected with a pathogen.
Abstract: The production of phytoalexins is a well-documented defense response against pathogen infection in rice. Although jasmonic acid has been suggested to be involved in the production of phytoalexins in both suspension-cultured rice cells and rice leaves, there has been almost no information on other secondary signaling molecules that regulate the production of phytoalexins in rice. In this study, the production of the major diterpenoid phytoalexins, momilactones and phytocassanes, was found to be induced by cytokinin treatment in both suspension-cultured rice cells and rice leaves, and also the upregulation of phytoalexin biosynthetic genes was found to be induced by cytokinin treatment. The roles of cytokinins in the production of diterpenoid phytoalexins in rice infected with a pathogen are discussed.
TL;DR: Disease resistance of Arabidopsis to Phytophthora brassicae is established by the combined action of iGS and camalexin, which are characteristic phytoanticipins of the Brassicaceae family includingArabidopsis.
Abstract: The model plant Arabidopsis thaliana contains a large arsenal of secondary metabolites that are not essential in development but have important ecological functions in counteracting attacks of pathogens and herbivores.1,2 Preformed secondary compounds are often referred to as phytoanticipins and metabolites, that are synthesized de novo in response to biotic stress are known as phytoalexins.3 Camalexin is the typical phytoalexin of Arabidopsis. It has antimicrobial activity towards some pathogens and was shown to be an important component of disease resistance in several plant pathogen interactions.4 Glucosinolates (GS) are characteristic phytoanticipins of the Brassicaceae family including Arabidopsis. GS are best known as repellents or attractants for herbivorous insects and their predators whereas their antimicrobial potential has received relatively little attention.5 The GS are glucosides and the biologically active aglycone is released upon biotic stress by glucohydrolase enzymes commenly called myrosinases. Because an Arabidopsis mutant susceptible to the oomycete pathogen Phytophthora brassicae shows a partial deficiency in both camalexin and iGS accumulation we became intrigued by the role of these secondary compounds in disease resistance.6,7 Our results show that disease resistance of Arabidopsis to P. brassicae is established by the combined action of iGS and camalexin.
TL;DR: Both yeast-form and mycelial growth of C. albicans were inhibited and yeast-to-hypha transition under serum-, pH-, and nutrient-induced hyphal growth conditions was impaired by resveratrol.
Abstract: The ability of the human fungal pathogen Candida albicans to undergo the morphological transition from a single yeast form to pseudohyphal and hyphal forms in response to various conditions is known to be important for its virulence. Many studies have shown the pharmacological effects of resveratrol, a phytoalexin polyphenolic compound. In this study, we investigated the antifungal activity of resveratrol against C. albicans. Both yeast-form and mycelial growth of C. albicans were inhibited by resveratrol. In addition, normal filamentation of C. albicans was affected and yeast-to-hypha transition under serum-, pH-, and nutrient-induced hyphal growth conditions was impaired by resveratrol.
TL;DR: The effects of SA treatment and the rolB transformation on VaPAL and VaSTS gene expression were found to be considerably different and compared with the earlier published data on PAL and STS genes of Vitis amurensis Rupr.
Abstract: Resveratrol is a phytoalexin with antibacterial, antiviral and cancer-preventing effects. The objective of the study was to identify PAL and STS genes of Vitis amurensis Rupr. encoding the phenylalanine ammonia-lyases (PAL) and stilbene synthases (STS), the key enzymes involved in the resveratrol biosynthesis. A V. amurensis Rupr. cell culture characterized by low resveratrol level was chosen as a model object. Salicylic acid (SA), a known secondary metabolism inducing agent, was used for enhancement of resveratrol production in this culture. PAL and STS gene expression was analyzed using the reverse transcription PCR and real-time PCR techniques. SA was originally found to specifically enhance the expression of VaPAL3, VaSTS2, VaSTS3, VaSTS4, VaSTS5, VaSTS6, and VaSTS8 of multigene families VaPAL and VaSTS. The results obtained were compared with the earlier published data on PAL and STS gene expression in the rolB transformed V. amurensis cell cultures characterized by high levels of resveratrol. The effects of SA treatment and the rolB transformation on VaPAL and VaSTS gene expression were found to be considerably different.
TL;DR: The regulatory mechanisms for phytoalexin biosynthesis through MAPK cascades and transcription factors in Arabidopsis and rice are discussed and compared.
Abstract: When plants sense the attack of microbial organisms, they initiate a series of defense responses. One of the most important defense components is the production of phytoalexins that are newly synthesized as anti-microbial secondary metabolites; however, knowledge about the signaling components regulating phytoalexin biosynthesis is limited. Mitogen-activated protein kinase (MAPK) cascades are key components in the defense signaling evoked by recognition of microbe-associated molecular patterns (MAMPs) that regulate several defense responses including phytoalexin biosynthesis. In Arabidopsis, biosynthesis of an indole-derived phytoalexin, camalexin, is regulated by MAPK cascades including AtMPK3, AtMPK4 and AtMPK6. Recently, we characterized a novel MAPK cascade in rice (OsMKK4-OsMPK3/OsMPK6) that induces production of diterpenoid phytoalexins by regulating the expression of their biosynthetic genes. Downstream signals of MAPK cascades are thought to be mediated by several transcription factors. To date, A...
TL;DR: Findings indicated that the production of phytoalexins in H. albus hairy roots yielded different products based on treatment with different chemicals (CuSO(4), MeJA, and MeJA-CuSO (4)).
Abstract: The production of sesquiterpene-type phytoalexins with a vetispyradiene skeleton by Hyoscyamus albus hairy roots induced by methyl jasmonate (MeJA) was reported in a previous paper. The production pattern on co-treatment with cupper sulfate and MeJA (CuSO4–MeJA) showed a TLC profile differing from that on treatment with MeJA. Thus, we studied the production of phytoalexins on hairy root culture involving co-treatment with CuSO4–MeJA. In the experiment, many sesquiterpene-type phytoalexins with a vetispyradiene skeleton were isolated, most of which were different from the products reported in the previous paper. Here, we isolated four new phytoalexins (1—4) along with known compounds 5—10 from the culture medium of H. albus hairy roots co-treated with MeJA–CuSO4. The structures of the new compounds (1—4) were determined as: (3R,4S,5R,7S,9R)-3-acetoxy-9-(2-methylpropionyloxy)solavetivone (1), (3R,4S,5R,7S,9R)-3-hydroxy-9-(3-methylbutanoyloxy)solavetivone (2), (3R,4S,5R,7S,9R)-3-acetoxy-9-(3-methyl-butanoyloxy)solavetivone (3), and (3R,4S,5R,7S,9R)-3-acetoxy-9-(3-methyl-2-butenoyloxy)-solavetivone (4) based on MS and NMR including 2D-NMR data. These findings indicated that the production of phytoalexins in H. albus hairy roots yielded different products based on treatment with different chemicals (CuSO4, MeJA, and MeJA–CuSO4).
TL;DR: A brief review of some biological, chemical and chemotaxonomic aspects of phytoalexin research is given in this article, focusing on the search for antifungal compounds in the plant families Leguminosae and Rosaceae, and in rice, Oryza sativa.
Abstract: A brief review is given of some biological, chemical and chemotaxonomic aspects of phytoalexin research. Emphasis is placed on the search for antifungal compounds in the plant families Leguminosae and Rosaceae, and in rice, Oryza sativa. The possible role of phytoalexins in the resistance of rice plants against the fungus Pyricularia oryzae (= Magnaporthe grisea) is discussed, and the future prospects of phytoalexin research are outlined.
Patent•
19 Nov 2010
TL;DR: In this article, a plant allelopathy effect or phyto-alexin production enhancing agent which includes an amino acid fermentation byproduct, a nucleic acid fermentation and amino acid or nucleic acids is applied to plants when cultivating the plants to suppress sprouting and growth of other plants at the periphery of the plants.
Abstract: PROBLEM TO BE SOLVED: To provide an allelopathy effect or phytoalexin production enhancing agent, increasing allelopathy effect or phytoalexin production like weeding effect and antibacterial action by performing foliar application or rhizosphere fertilization for grains, vegetables, fruit vegetables and plants such as garden plants, and maintaining an environment where weeds hardly grow, and to provide a method for enhancing allelopathy effect or phytoalexin production, using the agent.SOLUTION: This plant allelopathy effect or phytoalexin production enhancing agent which includes an amino acid fermentation byproduct, a nucleic acid fermentation byproduct, amino acid or nucleic acid is applied to plants when cultivating the plants to suppress sprouting and growth of other plants at the periphery of the plants.
TL;DR: In this paper, desoxyhemigossypol (dHG) and hemigossymol (HG), a phyto-alexin, were identified as part of the foliar resistance response to Xanthomonas campestris pv.
Abstract: Gossypium (cotton) spp. produce an array of sesquiterpenoid defense compounds, some of which accumulate in pigmof dHG and HG.ent glands and in root epidermis of healthy plants, and others which function as phytoalexins. Of the phytoalexins which accumulate in stem stele of Verticillium wilt-resistant cotton in response to Verticillium dahliae infection, Mace, Stipanovic and Bell (1985) Physiological Plant Pathology, 26, 209, have shown that desoxyhemigossypol (dHG) has the highest antifungal activity. Of the phytoalexins previously observed in foliar tissue of bacterial blight-resistant Gossypoium hirsutum in response to Xanthomonas campestris pv. malvacearum (Xcm) infection [2,7-dihydroxycadalene (DHC), lacinilene C, lacinilene C 7-methyl ether, and 2-hydroxy-7-methoxycadalene], DHC has the highest antibacterial activity. Both groups of phytoalexins have cadinane carbon skeletons, but they differ in the positions of oxygen-containing functional groups. dHG and its oxidation product hemigossypol (HG) have now been identified as part of the foliar resistance response to Xcm. A time course study showed that the bacterial blight-resistant, pigment-glandless G. hirsutum line WbMgl accumulated dHG and HG more quickly than the cadalene and lacinilene phytoalexins and to similar peak amounts (1–5 μmol/g fr. wt). Bioassays on logarithmically growing cultures of Xcm in defined liquid medium in the dark revealed that both dHG and HG have phytoalexin activity toward this pathogen, but are less potent than DHC. Whether dHG and HG contribute to resistance toward the infection by Xcm or play a different role depends on where these phytoalexins accumulate in inoculated cotyledons, which has yet to be determined.
Journal Article•
TL;DR: (E)-1,2-di(3,5-dimethoxyphenyl)ethene is evaluated as an obesity prevention agent and strongly downregulated the expression of fatty acid metabolism-related proteins such as fatty acid synthase and acetyl-CoA carboxylase.
Abstract: Resveratrol (trans-3,5,4'-trihydroxystilbene) is a phytoalexin found in diverse plant species, including grapes and peanuts. The antioxidant, anticancer, and cardioprotective properties of resveratrol have been well-characterized. The anti-obesity effect of resveratrol has also been demonstrated in previous studies. In this study, we evaluated the effects of a resveratrol analogue, (E)-1,2-di(3,5-dimethoxyphenyl)ethene, on adipocyte differentiation using 3T3-L1 cells. According to our results, the tested analogue potently inhibits the differentiation of 3T3-L1 adipocyte to a greater degree than resveratrol. Moreover, (E)-1,2-di(3,5-dimethoxyphenyl)ethene strongly downregulated the expression of fatty acid metabolism-related proteins such as fatty acid synthase and acetyl-CoA carboxylase. These results point to the potential of (E)-1,2-di(3,5-dimethoxyphenyl)ethene as an obesity prevention agent.
01 Jan 2010
TL;DR: In this paper, the authors focused upon the induction of resveratrol biosynthesis on in vitro vine culture conditions under the effect of AlCl3 as eliciting agent, which was performed through the high performance liquid chromatography (HPLC) using a Merck - Lunchrom pressure liquid chromatograph and a UV detector.
Abstract: Stillbenes are considered the most important phytoalexin group synthesized in the grapevine (Vitis vinifera) and they are known to contribute to the protection against various pathogens. The main typical stillbenes of grapevine, which show antifungal and pharmaceutical characteristics, are resveratrol and his derivatives. Recent studies highlight their benefit for the human health by their antifungal, anticarcinogen, hypolipidemic and antidiabetic properties, besides their already known fungitoxic characteristics. The present study focused upon the induction of resveratrol biosynthesis on in vitro vine culture conditions under the effect of AlCl3 as eliciting agent. The specific medium for vine multiplication (MS 0.03%; 0.05%). The resveratrol dosage was performed through the high performance liquid chromatography (HPLC), using a Merck - Lunchrom pressure liquid chromatograph and a UV detector. A more intensive resveratrol biosynthesis has been observed in the Cabernet Sauvignon variety, where the synthesized resveratrol quantity in the plant was up to 97.94 µg/g d.m. with a 0.05 % AlCl3 concentration in the culture medium.
TL;DR: An important group of isolates of the fungal species Leptosphaeria maculans, which is virulent to brown mustard, but not to canola, was used in this investigation and detoxified by the fungus, but none of the phytoalexins seemed to affect substantially the rate of brassilexin detoxification.
Abstract: The biotransformation of brassilexin, a potent phytoalexin produced by brown mustard (Brassica juncea L.), in the presence of various cruciferous phytoalexins was investigated. An important group of isolates of the fungal species Leptosphaeria maculans (Laird 2 and Mayfair 2), which is virulent to brown mustard, but not to canola, was used in this investigation. Brassilexin was detoxified by the fungus, but none of the phytoalexins seemed to affect substantially the rate of brassilexin detoxification; after 12 h of incubation, the amounts of brassilexin remaining in culture were as low as in controls, except in co-incubations with cyclobrassinin and sinalexin, which afforded intermediates that in solution oxidized spontaneously to brassilexin.
Journal Article•
TL;DR: Trans-resveratrol concentrations of wines produced from Cabernet sauvignon and Merlot black grapes which are grown in Ege, Marmara and Trakya regions of Turkey were determined by high performance liquid chromatography and correlation between the results and ecological conditions was researched.
Abstract: Phytoalexins are low molecular weight antimicrobial compounds whose production is elicited in plants in response to pathogen infection or treatment with various biotic and abiotic elicitors. Resveratrol (trans-3,5,4’-trihydroxystilbene) is a phytoalexin which can protect the host plant from fungal infection. Grapevine (Vitis vinifera), peanut (Arachis hypogaea) and several other plant species can accumulate resveratrol in leaves or in other parts at high concentrations. Resveratrol can be synthesized in different parts of the grapevine at high amounts, especially in the skin of berries which it passes into wine during wine making processes. The amount of resveratrol in pericarp of berries is higher than its flesh. Recently many researches were carried out on favorable impacts of resveratrol on human health due to its anticarcinogenic and antioxidant properties and its inclusion in daily diet is advised. In this study, trans-resveratrol concentrations of wines produced from Cabernet sauvignon and Merlot black grapes which are grown in Ege, Marmara and Trakya regions of Turkey were determined by high performance liquid chromatography and correlation between the results and ecological conditions was researched. It was observed that resveratrol concentrations can changes with grape type and ecological conditions.
01 Jun 2010
TL;DR: The findings indicated that metabolic engineering Carica papaya with heterologous phytoalexins, either under its own inducible promoter or a constitutive promoter, can improve plant defenses against fungal pathogens.
Abstract: Papaya (Carica papaya L.), one of the more important fruit crops of the tropics, has limited resistance to a range of fungal pathogens that may kill the plant or, at a minimum, reduce productivity and fruit quality. Phytoalexins have been shown to be important natural components in the defense of plants against pathogen infection. Several fruit crops, including grapes and peanuts, synthesize the stilbene-type phytoalexin, resveratrol, (trans-3,4', 5-trihydroxy-stilbene), when attacked by fungal pathogens such as, Botrytis circerea or Plasmopara viticola. The level of resistance to P. viticola was positively correlated with the capacity of Vitis spp. to synthesize stilbene. We conducted in-vitro pathogen inhibition assays to show that resveratrol also inhibited fungal pathogens of a tropical plant, papaya. Resveratrol at 1.0 mM in V8 agar culture medium inhibited mycelial growth of Phytophthora palmivora by up to 50%, as compared to the control. The compound was active against P. palmivora at concentrations as low as 100 μM. Resveratrol was not as effective against the anthracnose pathogen, Colletotrichum gloeosporiodes. Further, we transformed papaya embryogenic cultures with the stilbene synthase gene cloned from grapevine and driven by its own inducible promoter along with the hygromycin resistance or kanamycin resistance gene under the control of a CaMV35S promoter. The presence of the transgenes was confirmed by PCR and Southern blot analysis. Transgenic papaya plants were challenged with P. palmivora under greenhouse conditions. Data from greenhouse studies showed that the disease levels in transgenics plant were reduced to 35% of the disease levels in non-transformed control plants. Our findings indicated that metabolic engineering Carica papaya with heterologous phytoalexins, either under its own inducible promoter or a constitutive promoter, can improve plant defenses against fungal pathogens.
01 Jan 2010
TL;DR: Trans-resveratrol concentrations of wines produced from Cabernet sauvignon and Merlot black grapes which are grown in Ege, Marmara and Trakya regions of Turkey were determined by high performance liquid chromatography and correlation between the results and ecological conditions was researched.
Abstract: Phytoalexins are low molecular weight antimicrobial compounds whose production is elicited in plants in response to pathogen infection or treatment with various biotic and abiotic elicitors Resveratrol (trans-3,5,4’trihydroxystilbene) is a phytoalexin which can protect the host plant from fungal infection Grapevine (Vitis vinifera), peanut (Arachis hypogaea) and several other plant species can accumulate resveratrol in leaves or in other parts at high concentrations Resveratrol can be synthesized in different parts of the grapevine at high amounts, especially in the skin of berries which it passes into wine during wine making processes The amount of resveratrol in pericarp of berries is higher than its flesh Recently many researches were carried out on favorable impacts of resveratrol on human health due to its anticarcinogenic and antioxidant properties and its inclusion in daily diet is advised In this study, trans-resveratrol concentrations of wines produced from Cabernet sauvignon and Merlot black grapes which are grown in Ege, Marmara and Trakya regions of Turkey were determined by high performance liquid chromatography and correlation between the results and ecological conditions was researched It was observed that resveratrol concentrations can changes with grape type and ecological conditions