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出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2013/10/07 15:37:21」(JST)
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Phytotoxin refers to a substance produced by a plant that is toxic or a substance that is toxic to the plant.[1] Many substances produced by plants are secondary metabolites and are the by-products of primary physiological processes.[2] Some examples of phytotoxins exist among the plant secondary compound classes of alkaloids, terpenes, and especially phenolics, though not all such compounds are phototoxic. They can be found as well in herbicides and substances produced by bacteria.
Contents
- 1 Toxins Produced By Plants
- 1.1 Alkaloids
- 1.2 Terpenes
- 1.3 Phenolics
- 2 Substances Toxic to Plants
- 2.1 Herbicides
- 2.2 Bacterial Phytotoxins
- 3 See also
- 4 References
Toxins Produced By Plants[edit]
Alkaloids[edit]
Alkaloids are derived from amino acids, and contain nitrogen.[3] They are medically important by interfering with components of the nervous system affecting membrane transport, protein synthesis, and enzyme activities. They generally have a bitter taste. Alkaloids usually end in -ine (caffeine, nicotine, cocaine, morphine, ephedrine).
Terpenes[edit]
Terpenes are made of water insoluble lipids, and synthesized from acetyl CoA or basic intermediates of glycolysis[4] They often end in -ol (menthol) and make the majority of plant essential oils.
- Monoterpenes are found in gymnosperms and collect in the resin ducts and maybe released after an insect begins to feed to attract the insect's natural enemies.
- Sesquiterpenes are bitter tasting to humans and are found on glandular hairs or subdermal pigments.
- Diterpenes are contained in resin and block and deter insect feeding. Taxol, an important anticancer drug is found in this group.
- Triterpenes mimic the insect molting hormone ecdysone, disrupting molting and development and is often lethal. They are usually found in citrus fruit, and produce a bitter substance called limonoid that deters insect feeding.
- Glycosides are made of one or more sugars combined with a non-sugar like aglycone, which usually determines the level of toxicity. Cyanogenic glycosides are found in many plant seeds like cherries, apples,and plums. Cyanogenic glycosides produce cyanide and are extremely poisonous.Cardenolides have a bitter taste and influence NA+/K+ activated ATPases in human heart, they may slow or strengthen the heart rate. Saponins have lipid and water soluble components with detergent properties. Saponins form complexes with sterols and interfere with their uptake.
Phenolics[edit]
Phenolics are made of a hydroxyl group bonded to an aromatic hydrocarbon. Furanocoumarin is a phenolic and is non-toxic until activated by light. Furancoumarin blocks the transcription and repair of DNA. Tannins are another group of phenolics and they are important in tanning leather. Lignins, also a group of phenolics, is the most common compound on earth and helps conduct water in plant stems and fill spaces in the cell.
Substances Toxic to Plants[edit]
Herbicides[edit]
Herbicides usually interfere with plant growth and often imitate plant hormones.
- ACCase Inhibitors kill grasses and inhibit the first step in lipid synthesis, acetyl coA carboxylase,thus affecting cell memebrane production in the meristems. They do not affect dicots plants.[5]
- ALS Inhibitors affect grasses and dicots by inhibiting the first step in some amino acid synthesis, acetolactate synthesis. The plants are slowly starved of theses amino acids and eventually DNA synthesis stops.
- ESPS Inhibitors affect grasses and dicots by inhibiting the first step in the synthesis of tryptophan, phenylalanine and tyrosine, enolpyruvylshikimate 3-phosphate synthase enzyme.
- Photosystem II Inhibitors reduce the electron flow from water to NADPH2+ causing electrons to accumulate on chlorophyll molecules and excess oxidation to occur. The plant will eventually die.
- Synthetic Auxin mimics plant hormones and can affect the plant cell membrane.
Bacterial Phytotoxins[edit]
- Tabtoxin is produced by Pseudomonas syringae pv. tabaci that may cause toxic concentrations of ammonia to build up. This build up of ammonia causes leaf chlorosis.[6]
- Glycopeptides are produced by a number of bacteria and have been indicated in disease development.[6] A glycopeptide from Corynebacterium sepedonicum causes rapid wilt and marginal necrosis. A toxin from Corynebacterium insidiosum causes plugging of the plant stem interfering with water movement between cells.[6] Amylovorin is a polysaccharide from Erwinia amylovora and causes wilting in rosaceous plants. A polysaccharide from Xanthomonas campestris obstructs water flow through phloem causing black rot in cabbage.
- Phaseolotoxin is a modified tripeptide [Nδ-(N′-sulfodiaminophosphinyl)-ornithyl-alanyl-homoarginine] produced by certains strains of Pseudomonas syringae pv. phaseolicola, Pseudomonas syringae pv. actinidiae and strain Pseudomonas syringae pv. syringae CFBP 3388.[7][8][9] Phaseolotoxin is a reversible inhibitor of the enzyme ornithine carbamoyltransferase (OCTase; EC 2.1.3.3), which catalyzes the formation of citrulline from ornithine and carbamoylphosphate in the arginine biosynthetic pathway. Phaseolotoxin is an effective inhibitor of OCTase activity from plant, mammalian, and bacterial sources and causes a phenotypic requirement for arginine. Additionally, phaseolotoxin inhibits the enzyme ornithine decarboxylase (EC 4.1.1.17), which is involved in the biosynthesis of polyamines.[10]
- Rhizobiotoxine produced by Rhizobium japonicum causes the root nodules of some soy bean plants to become chlorotic.
See also[edit]
References[edit]
- ^ "Science Encyclopedia:Biochemistry" http://science.jrank.org/pages/39180/phytotoxin.html 2010/4/5.
- ^ Raven, Peter H,Ray F. Evert, Susan E. Eichhorn: "Biology of Plants", pages 27-33.
- ^ Zeiger, L. Taiz: "Plant Physiology: Plant Defenses" pages 349-376.
- ^ Plant Sciences "Poisonous Plants". pages 170-175.
- ^ Pike, David R., Aaron Hager, "How Herbicides Work" http://wed.aces.uiuc.edu/vista/pdf_pubs/herbwork.pdf
- ^ a b c Strobel,Gary A. 1977. Annual Review Microbiology "Bacterial Phytotoxins. 31:205-224
- ^ Bender CL, Alarcón-Chaidez F, Gross DC, 1999. Pseudomonas syringae phytotoxins: mode of action, regulation, and biosynthesis by peptide and polyketide synthetases. Microbiology and Molecular Biology Reviews 63, 266-292
- ^ Tourte C, Manceau C, 1995. A strain of Pseudomonas syringae which does not belong to pathovar phaseolicola produces phaseolotoxin. European Journal of Plant Pathology 101, 483-490
- ^ Murillo J, Bardaji L, Navarro de la Fuente L, Führer ME, Aguilera S, Alvarez-Morales A, 2011. Variation in conservation of the cluster for biosynthesis of the phytotoxin phaseolotoxin in Pseudomonas syringae suggests at least two events of horizontal acquisition. Research in Microbiology 162, 253-261
- ^ Bachmann AS, Matile P, Slusarenko AJ, 1998. Inhibition of ornithine decarboxylase activity by phaseolotoxin: Implications for symptom production in halo blight of French bean. Physiological and Molecular Plant Pathology 53, 287-299.
English Journal
- Physicochemical characterization of sewage sludge and green waste for agricultural utilization.
- Ramdani N1, Hamou A, Lousdad A, Al-Douri Y.
- Environmental technology.Environ Technol.2015 Jun;36(12):1594-604. doi: 10.1080/09593330.2014.998716. Epub 2015 Jan 13.
- In order to valorize the organic wastes, a mixture composed of 60 kg of thick sewage sludge from a wastewater treatment plant, 30 kg of green wastes (made of 10 kg straw of wheat, 10 kg manure farm wastes, and 10 kg of dead leaves), and 10 kg of wood chips was prepared. The organic waste
- PMID 25517858
- Comparative phytotoxicity of ZnO NPs, bulk ZnO, and ionic zinc onto the alfalfa plants symbiotically associated with Sinorhizobium meliloti in soil.
- Bandyopadhyay S1, Plascencia-Villa G2, Mukherjee A1, Rico CM3, José-Yacamán M2, Peralta-Videa JR4, Gardea-Torresdey JL5.
- The Science of the total environment.Sci Total Environ.2015 May 15;515-516:60-9. doi: 10.1016/j.scitotenv.2015.02.014. Epub 2015 Feb 17.
- ZnO nanoparticles (NPs) are reported as potentially phytotoxic in hydroponic and soil media. However, studies on ZnO NPs toxicity in a plant inoculated with bacterium in soil are limited. In this study, ZnO NPs, bulk ZnO, and ZnCl2 were exposed to the symbiotic alfalfa (Medicago sativa L.)-Sinorhizo
- PMID 25698520
- Oxidative damage and cell-programmed death induced in Zea mays L. by allelochemical stress.
- Ciniglia C1, Mastrobuoni F, Scortichini M, Petriccione M.
- Ecotoxicology (London, England).Ecotoxicology.2015 May;24(4):926-37. doi: 10.1007/s10646-015-1435-7. Epub 2015 Mar 4.
- The allelochemical stress on Zea mays was analyzed by using walnut husk washing waters (WHWW), a by-product of Juglans regia post-harvest process, which possesses strong allelopathic potential and phytotoxic effects. Oxidative damage and cell-programmed death were induced by WHWW in roots of maize s
- PMID 25736610
Japanese Journal
- Phytotoxic α-pyrones produced by Pestalotiopsis guepinii, the causal agent of hazelnut twig blight
- EVIDENTE Antonio,ZONNO Maria Chiara,ANDOLFI Anna,TROISE Ciro,CIMMINO Alessio,VURRO Maurizio
- Journal of antibiotics 65(4), 203-206, 2012-04-25
- NAID 10030641331
- もみ殻培地を用いた循環式バラ養液栽培における光触媒による排出培養液処理
- 深山 陽子,原 靖英,橋本 和仁,砂田 香矢乃
- 植物環境工学 24(1), 31-37, 2012-03-01
- From the viewpoint of conservation-oriented agriculture, this study investigated a closed cultivation system using a combination of rice hull substrate and TiO2 photocatalytic treat-ment of the waste …
- NAID 10030349952
- Isolation of Borrelidin as a Phytotoxic Compound from a Potato Pathogenic Streptomyces Strain
- CAO Zhisheng,KHODAKARAMIAN Gholam,ARAKAWA Kenji,KINASHI Haruyasu
- Bioscience, biotechnology, and biochemistry 76(2), 353-357, 2012-02-23
- <I>Streptomyces</I> species strain GK18, isolated in Iran, induced deep-pitted lesions on potato tubers, lesions different from the raised lesions induced by the usual scab-causing phytoto …
- NAID 10030400084
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- phytotoxic / ˌfaɪ təˈtɒk sɪk / Show Spelled [fahy-t uh-tok-sik] Show IPA adjective 1. of or pertaining to phytotoxin. 2. inhibitory to the growth of or poisonous to plants. Origin: 1930–35; phyto-+ toxic Related forms phytotoxicity / ˌfaɪ toʊ ...
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