Mechanisms of resistance to self-produced toxic secondary metabolites in plants

Sirikantaramas, Supaart; Yamazaki, Mami; Saito, Kazuki

doi:10.1007/s11101-007-9080-2

Cited by 121 publications

(99 citation statements)

References 98 publications

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“…Even so, for most plants its toxicological effects are still poorly described (Jordan et al, 2010;Street, Stirk, & Van Staden, 2008). Despite the secondary metabolites' toxicity (Sirikantaramas, Yamazaki, & Saito, 2008), other internal components can be toxic, as heavy metals often bio-accumulated by aromatic plants (Broadley et al, 2001;F.M. Ferreira et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

Antioxidant capacity and toxicological evaluation ofPterospartum tridentatumflower extracts

Ferreira

Dinis

Azedo

et al. 2012

CyTA - Journal of Food

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Pterospartum tridentatum Willk. (prickled broom) is an autochthonous plant, common in Portuguese territory. The yellow flowers are used in traditional medicine, as a potential cure for all body illnesses, mainly to treat throat irritations or for diabetes, hypertension and hypercholesterolemia therapy. Despite its traditional use, no toxicological assessment has been performed to our knowledge. A high antioxidant activity of P. tridentatum flower water extract was found, in good agreement with its electrospray ionisation-mass spectroscopy (ESI-MS) spectrum which revealed the presence of several flavonoids, such as luteolin-O-(O-acetyl)-glucuronide, luteolin-Oglucuronide or isorhamnetin-O-hexoside. Mitocondrial respiratory rates (state 4, state 3 and FCCP-stimulated respiration) and respiratory indexes (respiratory control and P/O ratios) showed no consistent decrease of respiratory and phosphorylative efficiencies for the concentrations tested (up to 500 mg.mL 71 ). Cytotoxicity evaluation, using MTT assay, was in agreement with the previous results. In conclusion, for the concentration range commonly used, P. tridentatum flower usage can be regarded as harmless and credible.Keywords: antioxidant capacity; cytotoxicity; oxidative phosphorylation; phytotherapy; Pterospartum tridentatum (L.); Willk.; toxicologic evaluation Pterospartum tridentatum Willk. es una planta auto´ctona comu´n en el territorio portugue´s. Las flores amarillas se usan en medicina tradicional como cura potencial para todas las enfermedades, especialmente para tratamientos de irritacio´n de garganta o para tratamientos contra diabetes, hipertensio´n o hipercolesterolemia. A pesar de su uso tradicional, ninguna evaluacio´n toxicolo´gica se ha llevado a cabo. Se encontro´una alta actividad antioxidante de extracto acuoso de flor de P. Tridentatum, concordando con su espectro ESI-MS, el cual revelo´la presencia de varios flavonoides, como luteolina O-(O-acetil)-glucuro´nido, luteolina-Oglucuro´nido o isorramntina-O-hexo´sido. Las frecuencias respiratorias mitocondriales (estado 4, estado 3 y respiracio´n estimulada por FCCP) mostraron un descenso no consistente de eficiencia respiratoria y fosforilativa para las concentraciones analizadas (hasta 500 mg.mL -1 ). La evaluacio´n de citotoxicidad, usando ensayo MTT, coincidio´con los resultados previos. En conclusio´n, para las concentraciones comu´nmente empleadas, el uso de las flores de P. tridentatum se puede considerar inocuo y verosı´mil.Palabras claves: capacidad antioxidante; citotoxicidad; fosforilacio´n oxidativa; fitoterapia; Pterospartum tridentatum (L.) Willk; evaluacio´n toxicolo´gica Abbreviations: ESI, electrospray ionization; FCCP, carbonyl cyanide p-trifluoromethoxyphenylhydrazone; HepG2, a human hepatoma cell line; MS, mass spectrometry; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; P/O ratio, ratio of ADP molecules phosphorylated to atoms of oxygen consumed; RCR, respiratory control ratio (state 3 respiratory rate/state 4 respiratory rate)

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Section: Discussionmentioning

confidence: 99%

Antioxidant capacity and toxicological evaluation ofPterospartum tridentatumflower extracts

Ferreira

Dinis

Azedo

et al. 2012

CyTA - Journal of Food

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“…This result suggests that the class I CfTPS3 and CfTPS4 can accept the copal-8-ol diphosphate synthesized by CfTPS2 and catalyze the stereospecific formation of (13R) manoyl oxide. Plants have evolved both specialized mechanisms and specialized anatomical structures for the secretion, sequestration, and accumulation of defense-related and potentially toxic molecules (Morant et al, 2008;Schilmiller et al, 2008;Sirikantaramas et al, 2008). These metabolites may otherwise display adverse activities for the producing plant cell.…”

Section: In Planta Heterologous Expression and Functional Characterizmentioning

confidence: 99%

“…processes and structures, such as interaction with membrane integrity (Uribe et al, 1985;Gershenzon and Dudareva, 2007;Sirikantaramas et al, 2008;Zore et al, 2011). Plant anatomical features and cellular structures typically associated with the biosynthesis and storage of large amounts of terpenoids are well studied and include glandular trichomes (Gershenzon et al, 2000;Iijima et al, 2004;Siebert, 2004;Schilmiller et al, 2008;Xie et al, 2008;Chatzopoulou et al, 2010;Lane et al, 2010), laticifer cells (Mahlberg, 1993;Post et al, 2012), resin cells, resin blisters, or resin ducts (Martin et al, 2002;Zulak and Bohlmann, 2010), and glandular cavities lined by epithelial cells (Heskes et al, 2012;Voo et al, 2012).…”

Section: In Planta Heterologous Expression and Functional Characterizmentioning

confidence: 99%

Manoyl Oxide (13R), the Biosynthetic Precursor of Forskolin, Is Synthesized in Specialized Root Cork Cells in Coleus forskohlii

et al. 2014

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“…Plants produce tens of thousands of secondary metabolites, which are classified as phenolics, terpenoids, alkaloids, glucosinolates, cyanogenic glucosides, and betanins. Secondary metabolites are secreted from the infected cells and their surrounding cells after pathogen attack or are released, hydrolyzed, and become toxic when the cells are destroyed by pathogens (1), thus inhibiting pathogen growth on the plant. Many secondary metabolites are dangerous to the plants because of their toxicity to cellular metabolism.…”

mentioning

confidence: 99%

Arabidopsis ABCG34 contributes to defense against necrotrophic pathogens by mediating the secretion of camalexin

Khare

Choi

Huh

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Plant pathogens cause huge yield losses. Plant defense often depends on toxic secondary metabolites that inhibit pathogen growth. Because most secondary metabolites are also toxic to the plant, specific transporters are needed to deliver them to the pathogens. To identify the transporters that function in plant defense, we screened Arabidopsis thaliana mutants of full-size ABCG transporters for hypersensitivity to sclareol, an antifungal compound. We found that atabcg34 mutants were hypersensitive to sclareol and to the necrotrophic fungi Alternaria brassicicola and Botrytis cinerea. AtABCG34 expression was induced by A. brassicicola inoculation as well as by methyl-jasmonate, a defense-related phytohormone, and AtABCG34 was polarly localized at the external face of the plasma membrane of epidermal cells of leaves and roots. atabcg34 mutants secreted less camalexin, a major phytoalexin in A. thaliana, whereas plants overexpressing AtABCG34 secreted more camalexin to the leaf surface and were more resistant to the pathogen. When treated with exogenous camalexin, atabcg34 mutants exhibited hypersensitivity, whereas BY2 cells expressing AtABCG34 exhibited improved resistance. Analyses of natural Arabidopsis accessions revealed that AtABCG34 contributes to the disease resistance in naturally occurring genetic variants, albeit to a small extent. Together, our data suggest that AtABCG34 mediates camalexin secretion to the leaf surface and thereby prevents A. brassicicola infection.AtABCG34 | ABC transporters | camalexin | A. brassicicola | B. cinerea P lants are exposed to a multitude of pathogens, but they usually resist infection by using their unique defense systems and compounds, including secondary metabolites produced either constitutively (phytoanticipins) or in response to pathogen attack (phytoalexins). Plants produce tens of thousands of secondary metabolites, which are classified as phenolics, terpenoids, alkaloids, glucosinolates, cyanogenic glucosides, and betanins. Secondary metabolites are secreted from the infected cells and their surrounding cells after pathogen attack or are released, hydrolyzed, and become toxic when the cells are destroyed by pathogens (1), thus inhibiting pathogen growth on the plant. Many secondary metabolites are dangerous to the plants because of their toxicity to cellular metabolism. To avoid self-toxicity, plants either secrete these compounds to the leaf surface or sequester them in the vacuole, a compartment with low metabolic activity. In both cases, specific transporters are required either to deliver the secondary metabolites to the site where the pathogens are located or to store them as weapons against pathogen attack.Several full-size ABCG transporters are involved in the transport of secondary metabolites. Nicotiana plumbaginifolia PDR1/ABC1 and Nicotiana tabacum PDR1 are induced by jasmonate, a defense-related hormone highly expressed in the leaf epidermal cells and trichomes, and transport sclareol, a diterpene alcohol secreted by Nicotiana species in response to p...

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Mechanisms of resistance to self-produced toxic secondary metabolites in plants

Cited by 121 publications

References 98 publications

Antioxidant capacity and toxicological evaluation ofPterospartum tridentatumflower extracts

Antioxidant capacity and toxicological evaluation ofPterospartum tridentatumflower extracts

Manoyl Oxide (13R), the Biosynthetic Precursor of Forskolin, Is Synthesized in Specialized Root Cork Cells in Coleus forskohlii

Arabidopsis ABCG34 contributes to defense against necrotrophic pathogens by mediating the secretion of camalexin

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