Biological activity of dhurrin and other compounds from Johnson grass (Sorghum halepense)

Nicollier, Gilles; Pope, Daniel F.; Thompson, A. C.

doi:10.1021/jf00118a016

Cited by 61 publications

(38 citation statements)

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“…Como se trabalhou com quantidades de palha equivalentes entre os genótipos, essas diferenças podem ser atribuídas a variações qualitativas e quantitativas na liberação de substâncias pela parte aérea das plantas em decomposição. Resíduos de sorgo em decomposição liberam quantidades expressivas de substâncias hidrofílicas, em sua maioria ácidos fenólicos, como ferúlico, vaní-lico, p-hidroxibenzóico, p-cumárico e siríngico (Guenzi & McCalla, 1966;Nicollier et al, 1983;Weston et al, 1999). As concentrações totais de substâncias fenólicas em plantas de sorgo variam entre genótipos, com a parte da planta e com a estação de crescimento (Ben-Hammouda et al, 1995).…”

Section: Resultsunclassified

“…Resíduos de sorgo em decomposição liberam compostos de natureza hidrofílica, em sua maioria ácidos fenólicos, como os ácidos ferú-lico, vanílico, siríngico, p-hidroxibenzóico e, especialmente, p-cumárico (Guenzi & McCalla, 1966;Nicollier et al 1983;Weston et al, 1999). Variações consideráveis desses compostos foram encontradas em tecidos vegetais e no solo quando foram comparados três genótipos de sorgo (Ben-Hammouda et al, 1995).…”

Section: Introductionunclassified

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Potencial de utilização de cobertura vegetal de sorgo e milheto na supressão de plantas daninhas em condição de campo: II - Efeitos da cobertura morta

Trezzi¹,

Vidal

2004

Planta daninha

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RESUMO -A capacidade de supressão de plantas daninhas por culturas de cobertura é bastante conhecida e explorada, embora seja pouco pesquisada a importância relativa dos efeitos físicos e alelopáticos sobre esse fenômeno. Dois experimentos foram realizados a campo, em 1999/2000 e 2000/2001, na área experimental da Faculdade de Agronomia da UFRGS, no delineamento experimental em blocos ao acaso, com quatro repetições, objetivando determinar os efeitos da cobertura morta de plantas de sorgo e de milheto sobre a supressão de plantas daninhas. Nos dois anos de condução dos experimentos, os tratamentos resultaram de um fatorial, em que o fator A foi constituído pelos genótipos de sorgo RS 11, BR 601 e BR 304, representantes de três classes de produção de extratos radiculares hidrofóbicos em laboratório, pelo genótipo de milheto Comum RS e por uma testemunha sem culturas; e o fator B, constituído por níveis de palha de cada genótipo sobre o solo. Em 1999/2000, níveis de palha de sorgo de 1,3 t ha -1 foram suficientes para reduzir 50% das infestações de Brachiaria plantaginea (BRAPL) e Sida rhombifolia (SIDRH). Em 2000/2001, 4 t ha -1 de palha de sorgo ou milheto foram suficientes para reduzir 91, 96 e 59% da população total de SIDRH, BRAPL e Bidens pilosa, respectivamente. A presença de resíduos da parte aérea de sorgo é mais importante na supressão de plantas daninhas do que a presença de resíduos das raízes dessa cultura.Palavras-chave : Sorghum spp., Pennisetum americanum, níveis de palha, alelopatia, fatores físicos. , in 1999/2000 and 2000/ 2001, at ABSTRACT -The weed supression capacity of cover crops is well known and explored, although only a few works have been conducted on the relative importance of the physical and allelopathic effects on this phenomenon. Two trials were carried out in the field

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Section: Resultsunclassified

Section: Introductionunclassified

Potencial de utilização de cobertura vegetal de sorgo e milheto na supressão de plantas daninhas em condição de campo: II - Efeitos da cobertura morta

Trezzi¹,

Vidal

2004

Planta daninha

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“…Sorghum species produce cyanogenic glycosides, tannins, several flavonoids, and phenolic acids such as ferulic, /?-coumaric, syringic, vanillic, and (116)(117)(118)(119)(120)(121)(122)(123)(124)(125). Recent evidence has added root exudate /7-benzoquinones, known as sorgoleone, to the chemicals causing Sorghum allelopathy (126)(127).…”

Section: Mechanism Of Sorghum Allelopathymentioning

confidence: 99%

Mechanism of Action of Allelochemicals in Allelopathy

Einhellig

1994

ACS Symposium Series

214

170

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The primary mode of action has not been established for any allelopathic compound, albeit some physiological actions are known. The array of compounds cuts across many chemical classes, and it is unlikely they have a common mechanism of action. Allelochemicals active against higher plants are typically characterized as suppressing seed germination, causing injury to root growth and other meristems, or inhibiting seedling growth.A primary action on ATP production is indicated for the two quinones, juglone and sorgoleone, since they inhibit chloroplast oxygen evolution (I 50 = 0.2 and 2.0 μM respectively) and strongly affect mitochondrial functions.The chloroplast block by sorgoleone is in the photosystem II complex. Cinnamic and benzoic acid derivatives alter membrane potential and have several physiological effects that suggest membrane perturbations are their initial site of action. Their thresholds (100 to 1000 μM) for inhibition of seedling growth, singly or in combinations, correlate with impairment of plant-water relationships. These phenolic compounds also alter mineral uptake, chlorophyll content, photosynthesis, carbon flow, and phytohormone activity. Phytotoxicity of many allelopathic chemicals may be from a generalized cellular disruption rather than a specific mechanism. A case study of Sorghum allelopathy suggests that inhibition of a receiving species results from the joint action of a number of allelochemicals with different cellular sites of action.Efforts to explain the phenomenon of allelopathy are ultimately challenged to identify the site, or sites, of action of the chemicals involved. However, this lofty goal has seldom come to fruition (1). Success has been greatest in localizing the subcellular target of activity for certain antibiotics and other microbial toxins (2-4).

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“…In grain sorghum and other sorghum species the cyanogenic glycoside dhurrin is a potential microbial toxicant but is best considered an insect feeding deterrent and phytotoxin rather than a stress metabolite (5)(6)(7). Dhurrin, present in relatively high concentration in uninfected tissue, does not increase following microbial infection (8,9) and the dhurrin content of tissue decreases with maturation (10).…”

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confidence: 99%

Phytoalexin synthesis by the sorghum mesocotyl in response to infection by pathogenic and nonpathogenic fungi

Nicholson

Kollipara²,

Vincent³

et al. 1987

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

127

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Infection of the sorghum mesocotyl by Helminthosporium maydis (a nonpathogen) and Colletotrichum graminicola (a pathogen) resulted in the rapid accumulation of a pigment complex by two sorghum cultivars. The components of the complex were fungitoxic. The principal compounds have been identified as the 3-deoxyanthocyanidins apigeninidin and luteolinidin. Apigeninidin accumulated in both sorghum cultivars in response to infection and was the predominant pigment. Luteolinidin accumulated in only one of the cultivars. Because of the speed of synthesis, occurrence only in response to inoculation, and fungitoxicity of the individual components, we propose that synthesis of the pigment complex constitutes a defense response and that the compounds apigeninidin and luteolinidin should be considered as phytoalexins.With the exception of the momilactones from rice (1, 2) and the avenalumins from oat (3, 4), phytoalexins have not been identified in members of the Gramineae. In grain sorghum and other sorghum species the cyanogenic glycoside dhurrin is a potential microbial toxicant but is best considered an insect feeding deterrent and phytotoxin rather than a stress metabolite (5-7). Dhurrin, present in relatively high concentration in uninfected tissue, does not increase following microbial infection (8, 9) and the dhurrin content of tissue decreases with maturation (10).The situation in sorghum is further complicated by the fact that seedling leaves exhibit few if any symptoms when inoculated with various fungi. Probably the most pronounced example of this phenomenon is foliar anthracnose caused by Colletotrichum graminicola. In this disease both resistant and susceptible cultivars are resistant in the seedling stage and plants must be about 5 weeks old before they will exhibit symptoms in response to inoculation (11). Such observations have led to the assumption that seedling resistance is the result of the presence of dhurrin (11). However, Fry and coworkers (8,9,12,13) have demonstrated that fungal pathogens of cyanogenic plants produce formamide hydrolyase, which detoxifies hydrogen cyanide, the toxic breakdown product of dhurrin, by converting it to formamide. Therefore, that dhurrin has a role in seedling resistance, either to pathogens or to nonpathogens, is not yet clear.The purpose of this investigation was to evaluate whether resistance in sorghum is associated with the accumulation of previously undetected toxic host metabolites. We describe the rapid accumulation of phytoalexins in the sorghum mesocotyl as a response to attempted infection by a speciespathogenic and a species-nonpathogenic fungus. MATERIALS AND METHODSPathogens, Plant Material, and Inoculation. The fungi Helminthosporium maydis Nisik. and Miy., race 0, and Colletotrichum graminicola (Ces.) Wils. were grown and spore suspensions were prepared for inoculum as described (14,15). Inoculum concentrations were 5 x i04 spores per ml for H. maydis and 106 spores per ml for C. graminicola.Tween 20 was used as a wetting agent (100 tkl per 100 ...

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Biological activity of dhurrin and other compounds from Johnson grass (Sorghum halepense)

Cited by 61 publications

References 6 publications

Potencial de utilização de cobertura vegetal de sorgo e milheto na supressão de plantas daninhas em condição de campo: II - Efeitos da cobertura morta

Potencial de utilização de cobertura vegetal de sorgo e milheto na supressão de plantas daninhas em condição de campo: II - Efeitos da cobertura morta

Mechanism of Action of Allelochemicals in Allelopathy

Phytoalexin synthesis by the sorghum mesocotyl in response to infection by pathogenic and nonpathogenic fungi

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