Hydroxylation of primisulfuron by an inducible cytochrome P450-dependent monooxygenase system from maize

Fonné‐Pfister, Raymonde; Gaudin, John; Kreuz, Klaus; Ramsteiner, K.; Ebert, E.

doi:10.1016/0048-3575(90)90122-i

Cited by 88 publications

(55 citation statements)

References 13 publications

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“…Seus sintomas, em plantas sensíveis, são caracterizados por clorose foliar, necrose e redução do crescimento (Brow, 1990;Fonne-Pfister et al, 1990). Dos herbicidas deste grupo químico, o nicosulfuron é utilizado principalmente em aplicações em pós-emergência, com enfoque no controle de gramíneas e algumas espécies dicotiledôneas (Rodrigues & Almeida, 1998).…”

Section: Introductionunclassified

Formação de pastagem via consórcio de Brachiaria brizantha com o milho para silagem no sistema de plantio direto

Freitas

Ferreira

et al. 2005

Planta daninha

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RESUMO -Este trabalho teve como objetivo avaliar arranjos de semeadura e manejo de plantas daninhas na implantação de pastagem de B. Brizantha cv. MG5 Vitória consorciada com milho para silagem no sistema de plantio direto. Foram avaliados cinco arranjos de semeadura (milho em monocultivo; B. brizantha em monocultivo; duas linhas de B. brizantha na entrelinha do milho, em semeadura simultânea; B. brizantha a lanço no dia da semeadura do milho e 30 dias após), combinados com dois manejos de plantas daninhas (1,50 kg ha -1 de atrazine aplicado isoladamente e a mistura no tanque de 1,50 kg ha de nicosulfuron), mais quatro testemunhas (milho e B. brizantha em monocultivo, com e sem capina), no delineamento de blocos ao acaso, em parcelas subdivididas, sendo os arranjos de semeadura colocados nas parcelas e os sistemas de manejo nas subparcelas, totalizando 14 tratamentos, com quatro repetições. A aplicação dos herbicidas foi feita aos 18 dias após a emergência do milho. Trinta dias depois da aplicação dos herbicidas e na colheita do milho para silagem, foram avaliadas as biomassas secas das plantas daninhas e de B. brizantha. Aos 60 dias após a colheita, fez-se nova avaliação da biomassa seca de braquiária. A infestação de plantas daninhas foi baixa e a produção de milho para silagem não foi influenciada pelos arranjos de semeadura nem pelos sistemas de manejo de plantas daninhas, demonstrando que, mesmo em semeadura simultânea, B. brizantha não afeta a produtividade do milho para silagem. Maior produção de biomassa seca de forragem foi obtida com o arranjo de duas linhas de B. brizantha na entrelinha do milho, em semeadura simultânea.Palavras-chave: consorciação, arranjos de semeadura, competição, manejo cultural. ABSTRACT -The objective of this work was to evaluate the arrangements of weed sowing and management for the implantation of

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Section: Introductionunclassified

Formação de pastagem via consórcio de Brachiaria brizantha com o milho para silagem no sistema de plantio direto

Freitas

Ferreira

et al. 2005

Planta daninha

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“…Diclofop hydroxylation was shown to be inhibited by tetcyclasis, an established Cyt P-450 inhibitor (20). Primsulfuron, a sulfonurea herbicide which inhibits plant acetohydroxyacid synthase in the branched chain amino acid pathway, was found to be hydroxylated in two different positions by maize seedling microsomes (7). Primsulfuron, chlorotoluron and diclofop hydroxylations all required 02 and were inhibited by CO with at least some reversal of the inhibition by white light, implicating a Cyt P-450 in each of the hydroxylations.…”

Section: Some Plant Cyt P-450 May Be Involved In Modification Of Herbmentioning

confidence: 99%

Multiple Forms of Plant Cytochromes P-450

Donaldson¹,

Luster²

1991

Plant Physiol.

159

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Accumulating evidence indicates that there is a multiplicity of cytochrome P-450 enzymes in plants. These monooxygenases are implicated in the metabolism of sterols, terpenes, gibberellins, isoflavonoids, and xenobiotics. Evidence that cytochromes P-450 are involved in the detoxification of herbicides (chlorotoluron, primsulfuron, and diclofop) includes photoreversible CO inhibition of the reactions, and a requirement for 02 and NADPH. Several cytochromes P-450, Mr 45,000 to 65,000, have been isolated, including hydroxylases of cinnamic acid, 3,9-dihydroxypterocarpan, and digitoxin. In some cases the purified cytochrome P-450 has been successfully reconstituted with NADPH:cytochrome P-450 reductase (Mr 72,000-84,000 protein). This reductase appears to be a nonspecific electron donor to different forms of cytochrome P-450. Immunological techniques and specific inhibitors (triazoles, imidazole derivatives) are being used to characterize plant cytochromes P-450 and the NADPH:cytochrome P-450 reductase. Specific cytochromes P-450 are induced by wounding or pathogens, others are expressed in specific cell types. Plant cytochromes P-450 are found in various subcellular locations, including endoplasmic reticulum, plasma membranes, glyoxysomes, and perhaps mitochondria. A cytochrome P-450 demethylase from avocado has recently been sequenced and found to have a hydrophobic N terminus similar to the membrane anchor of cytochromes P-450 from other organisms. The existence of cytochromes P-450 in different subcellular locations suggests that there are many genes for cytochromes P-450 in plants which have yet to be identified and classified.Cyt P-450 are membrane-bound heme-containing proteins which have been implicated in a variety of oxidative reactions in plant tissues. A wide range of reactions are mediated by specific forms of these proteins. Cyt P-450-linked enzymes have been implicated in biosynthetic pathways leading to the synthesis of lignin phenolics, membrane sterols, phytoalexins, and terpenoids (33). It has been postulated that plants have evolved highly specific Cyt P-450-linked secondary pathways to produce defense-related phytoalexins, while animals have evolved parallel less specific, Cyt P-450-linked systems to detoxify ingested phytoalexins and other xenobiotics (11,22 at the expense of the 450 nm peak (25). For this reason the CO-hemoprotein adduct with the 420 nm peak, termed P-420, is often considered to be a degradation product of Cyt P-450.In addition to the nonspecific inhibition by CO, certain Cyt P-450 activities are selectively inhibited by various imidazole, pyrimidine, and triazole derivatives. Inhibitor binding also can be determined spectrophotometrically by changes in difference spectra. A typical Cyt P-450 spectrum of any mem-669 www.plantphysiol.org on May 10, 2018 -Published by Downloaded from

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“…Tolerant species detoxify these herbicides very fast, turning them into non-phytotoxic compounds through the action of cytochrome P450 monooxygenases, in reactions of hydroxylation and glyoxylation (Fonne-Pfister, Gaudin, Kreuz, Ramsteiner, & Ebert, 1990).…”

Section: Resultsmentioning

confidence: 99%

Maximum quantum yield of photosystem II to assist in the measurement of herbicide selectivity in popcorn

Freitas¹,

Rodrigues²,

Amaral³

et al. 2014

Plant Sci Today

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The objective of this study was to evaluate the selectivity/phytotoxicity of herbicides (mesotrione, nicosulfuron, and tembotrione) using the maximum quantum yield of photosystem II associated with biometric analyses. The experiment was conducted using three popcorn genotypes (BRS Angela, IAC-125 and UENF-14) and three herbicides (mesotrione, tembotrione and nicosulfuron, and a control treatment "WITH WEEDING?". The quantum yield of photosystem II was obtained through a modulated light portable fluorometer MINI-PAM, from the chlorophyll a fluorescence. Regarding the biometric analyses, the following characteristics were evaluated: a) number medium of ears of the corn, b) grain yield in kg ha -1 , c) average weight of 100 grains, and d) popping expansion. The genotypes were sensitive to tembotrione with higher intensity for the IAC -125. The maximum quantum yield of photosystem II showed useful tool for studies of selectivity/phytotoxicity symptoms of herbicides used.

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Hydroxylation of primisulfuron by an inducible cytochrome P450-dependent monooxygenase system from maize

Cited by 88 publications

References 13 publications

Formação de pastagem via consórcio de Brachiaria brizantha com o milho para silagem no sistema de plantio direto

Formação de pastagem via consórcio de Brachiaria brizantha com o milho para silagem no sistema de plantio direto

Multiple Forms of Plant Cytochromes P-450

Maximum quantum yield of photosystem II to assist in the measurement of herbicide selectivity in popcorn

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