Phytoalexins produced in the leaves of Capsella bursa-pastoris (shepherd’s purse)

Jiménez, Lourdes Díaz; Ayer, William A.; Tewari, J. P.

doi:10.7202/706124ar

Cited by 34 publications

(19 citation statements)

References 15 publications

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“…1) is an indole phytoalexin that accumulates in various cruciferous plants, e.g. Camelina sativa, Arabidopsis thaliana, and Capsella bursa-pastoralis, in response to plant pathogen attack or abiotic stress [1][2][3]. It displays antimicrobial activity against some bacterial and fungal plant pathogens, including Pseudomonas syringae, Alternaria brassicicola, Alternaria brassicaeae, and Leptosphaeria maculans, reportedly via its cell membrane disrupting effect [4].…”

Section: Introductionmentioning

confidence: 99%

Camalexin induces apoptosis in T-leukemia Jurkat cells by increased concentration of reactive oxygen species and activation of caspase-8 and caspase-9

et al. 2011

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Camalexin, a major indole phytoalexin of Arabidopsis thaliana, accumulates in various cruciferous plants in response to environmental stress and reportedly displays antimicrobial activities against various plant pathogens. However, its cytotoxicity against eukaryotic cells and potential as a prospective drug for human diseases has been examined only in a limited context. Our data demonstrate the time- and concentration-dependent cytotoxicity of camalexin on human T-leukemia Jurkat cells in the micromolar range, and the lower potency of cytotoxic effects on human lymphoblasts and primary fibroblasts. Cytotoxicity of camalexin is enhanced by the glutathione-depleting agent buthionine sulfoximine and completely blocked by pan-caspase inhibitor Z-VAD-FMK. Treatment of Jurkat cells with camalexin resulted in activation of caspase-8, caspase-9, caspases-3/7, and apoptosis that was detected by the presence of a sub-G1 population of cells, externalization of phosphatidyl serine and decreased mitochondrial membrane potential. Staining with 2',7'-dichlorodihydrofluorescein diacetate and dihydroethidium bromide displayed increased concentration of reactive oxygen species (ROS) early in camalexin-treated Jurkat cells, prior to the onset of apoptosis, while staining with MitoSOX(™) dye identified mitochondria as a source of increased ROS. Our data suggest that this phytochemical, which has a wide range of predicted pharmacological activities, induces apoptosis in Jurkat leukemia cells through increased ROS followed by dissipation of mitochondrial membrane potential and execution of caspase-9- and caspase-8-initiated apoptosis. This is, to the best of our knowledge, the first report on antileukemic activity and mode of action of this unique indole phytoalexin.

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Section: Introductionmentioning

confidence: 99%

Camalexin induces apoptosis in T-leukemia Jurkat cells by increased concentration of reactive oxygen species and activation of caspase-8 and caspase-9

et al. 2011

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“…Although chemical diversification represents a widespread strategy in nature to enhance the toxicity of phytoalexins, simple camalexin derivatives, such as 6-methoxycamalexin or N-methylcamalexin, which were reported to occur in other camalexin producing species like Capsella bursa-pastoris (Jimenez et al, 1997) and Camelina sativa (Browne et al, 1991), were surprisingly lacking in Arabidopsis. Instead, major metabolic transformations of camalexin in leaf tissue include sequential hydroxylation, O-glycosylation, and malonylation, resulting in accumulation of two different hydroxycamalexin hexosides (2 and 3) and a malonyl derivative (4) as analogously reported for indole-3-carboxylate in Arabidopsis leaf and root tissue (Hagemeier et al, 2001;Bednarek et al, 2005).…”

Section: A Metabolomics Approach For the Detection Of Novel Biosynthementioning

confidence: 99%

The Multifunctional Enzyme CYP71B15 (PHYTOALEXIN DEFICIENT3) Converts Cysteine-Indole-3-Acetonitrile to Camalexin in the Indole-3-Acetonitrile Metabolic Network ofArabidopsis thaliana

et al. 2009

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Accumulation of camalexin, the characteristic phytoalexin of Arabidopsis thaliana, is induced by a great variety of plant pathogens. It is derived from Trp, which is converted to indole-3-acetonitrile (IAN) by successive action of the cytochrome P450 enzymes CYP79B2/B3 and CYP71A13. Extracts from wild-type plants and camalexin biosynthetic mutants, treated with silver nitrate or inoculated with Phytophthora infestans, were comprehensively analyzed by ultra-performance liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry. This metabolomics approach was combined with precursor feeding experiments to characterize the IAN metabolic network and to identify novel biosynthetic intermediates and metabolites of camalexin. Indole-3-carbaldehyde and indole-3-carboxylic acid derivatives were shown to originate from IAN. IAN conjugates with glutathione, g-glutamylcysteine, and cysteine [Cys(IAN)] accumulated in challenged phytoalexin deficient3 (pad3) mutants. Cys(IAN) rescued the camalexin-deficient phenotype of cyp79b2 cyp79b3 and was itself converted to dihydrocamalexic acid (DHCA), the known substrate of CYP71B15 (PAD3), by microsomes isolated from silver nitrate-treated Arabidopsis leaves. Surprisingly, yeast-expressed CYP71B15 also catalyzed thiazoline ring closure, DHCA formation, and cyanide release with Cys(IAN) as substrate. In conclusion, in the camalexin biosynthetic pathway, IAN is derivatized to the intermediate Cys (IAN), which serves as substrate of the multifunctional cytochrome P450 enzyme CYP71B15.

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“…Brassica pathogens including Alternaria brassicae has been associated with the production of camalexin as the major antifungal compound, as well as smaller quantities of a related compound, 6-methoxycamalexin (Jejelowo et al, 1991;Jimenez et al, 1997;). …”

Section: Capasella Sativa and C Bursa-pastoris To Differentmentioning

confidence: 99%

Induced plant secondary metabolites for phytopatogenic fungi control: a review

Ribera

Zúñiga

2012

J. Soil Sci. Plant Nutr.

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Pathogenic fungi constitute one of the main infectious agents in plants, causing alterations during developmental stages including post-harvest. Phytopathogenic fungi are controlled by synthetic fungicides; however, the use of these is progressively restricted due to both, the harmful effects of pesticides on the environment and human health and the appearance of highly resistant fungal strains. Therefore, there is a great demand for novel natural fungicides. Higher plants are rich source of bioactive secondary metabolites of wide variety such as tannins, terpenoids, saponins, alkaloids, flavonoids, and other compounds, reported to have in vitro antifungal properties. Thus, secondary metabolites with antifungal activity represent an alternative for achieving a sustainable control of phytopathogenic fungi and to reduce the heavy reliance of synthetic pesticides used to control them. Plant antifungal metabolites may be preformed inhibitors that are present constitutively in healthy plants (phytoanticipins), or they may be synthesized de novo in response to pathogen attack or another stress conditions (phytoalexins). These molecules may be used directly or considered as a precursor for developing better fungicidal molecules. This review presents a selection of antifungal agents induced in plants during fungal attack that can be potentially used for phytopathogenic fungi control in crops.

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Phytoalexins produced in the leaves of Capsella bursa-pastoris (shepherd’s purse)

Cited by 34 publications

References 15 publications

Camalexin induces apoptosis in T-leukemia Jurkat cells by increased concentration of reactive oxygen species and activation of caspase-8 and caspase-9

Camalexin induces apoptosis in T-leukemia Jurkat cells by increased concentration of reactive oxygen species and activation of caspase-8 and caspase-9

The Multifunctional Enzyme CYP71B15 (PHYTOALEXIN DEFICIENT3) Converts Cysteine-Indole-3-Acetonitrile to Camalexin in the Indole-3-Acetonitrile Metabolic Network ofArabidopsis thaliana

Induced plant secondary metabolites for phytopatogenic fungi control: a review

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