Tissue and cellular localization of acifluorfen-induced porphyrins in cucumber cotyledons

Lehnen, Larry P.; Sherman, Timothy D.; Becerril, José M.; Duke, Stephen O.

doi:10.1016/0048-3575(90)90130-t

Cited by 75 publications

(73 citation statements)

References 36 publications

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“…The image indicates that Proto IX possibly produced by the enzymatic oxidation of Protogen is distributed throughout the intracellular space. This pattern is similar to that reported by Lehnen et al 13) who showed that Proto IX fluorescence was distributed in acifluorfentreated cucumber disks. In the resistant cells, chlorophyll autofluorescence was observed in most of the nontreated cells (Fig.…”

Section: Discussionsupporting

confidence: 80%

Differential Accumulation of Protoporphyrin IX between Oxyfluorfen Resistant and Non-Resistant Soybean Cell Lines

2002

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The diphenyl ether herbicide oxyfluorfen causes an accumulation of protoporphyrin IX (Proto IX) in plants as a result of the inhibition of protoporphyrinogen oxidase (Protox). We previously reported that an oxyfluorfen-resistant soybean cell line selected by a stepwise selection method grew normally under 10-' M oxyfluorfen due to the overproduction of mitochondrial Protox. In the present study, the accumulation and localization of Proto IX in normal and resistant cells after treatment with oxyfluorfen were examined by spectrofluorometry and fluorescence microscopy. The normal cells accumulated great amounts of Proto IX in the presence of 10-6 and 10-M oxyfluorfen whereas the resistant cells accumulated much less. The level of Proto IX reached a maximum at 4 to 8 hr after treatment under illumination and then gradually decreased. In the dark, the Proto IX content increased linearly until 24 hr and fluorescence from Proto IX was detected in cytoplasm and plasma membrane in the oxyfluorfen-treated normal cells. In resistant cells, chlorophyll autofluorescence was detected in non-treated cells, and Proto IX fluorescence was not detectable. This autofluorescence, however, disappeared with 10-7M oxyfluorfen treatment. These results strongly support that the overproduction ofmitochondrial Protox is responsible for the resistance to oxyfluorfen in this selected soybean cell line.

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Section: Discussionsupporting

confidence: 80%

Differential Accumulation of Protoporphyrin IX between Oxyfluorfen Resistant and Non-Resistant Soybean Cell Lines

2002

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“…Protogen IX, being significantly less lipophilic than Proto IX, would have a tendency to escape the plastid envelope. Proto IX, being more lipophilic than Protogen IX, tends to accumulate in the PM, where it can be observed by fluorescence microscopy (Lehnen et al, 1990;Duke et al, 1991b). The latest results of Jacobs and Jacobs (1993) clearly demonstrate that Protogen IX is readily exported from intact, AFM-treated plastids.…”

Section: Discussionmentioning

confidence: 99%

“…Vol. 102,1993 however, there is some evidence of reentry in the absence of herbicidal damage in darkness (Lehnen et al, 1990).…”

mentioning

confidence: 99%

“…Thus, escape of the substrate, Protogen IX, to the cytoplasm in Protox-inhibited plastids is plausible. Furthermore, fluorescence microscopy revealed that Proto IX, which accumulates in these herbicide-treated cells, appeared to accumulate primarily outside the plastid (Lehnen et al, 1990;Duke et al, 1991b). Much of the porphyrin fluorescence appeared to be associated with the PM.…”

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confidence: 99%

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Cellular Localization of Protoporphyrinogen-Oxidizing Activities of Etiolated Barley (Hordeum vulgare L.) Leaves (Relationship to Mechanism of Action of Protoporphyrinogen Oxidase-Inhibiting Herbicides)

1993

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Seven-day-old, etiolated barley (Hordeum vulgare 1. var Post) leaves were fractionated into crude and purified etioplast, microsomal, and plasma membrane (PM) fractions. Protoporphyrinogen oxidase (Protox) specific activities of crude etioplast, purified etio- reduced the Protox activity of all fractions, except that microsomal Protox activity was slightly stimulated by NADPH. Ascorbate, CSH, or a combination of the two reductants enhanced Protox inhibition by AFM, and AFM inhibition of Protox was greatest in all fractions with DTT. NADPH enhanced AFM inhibition significantly only in etioplast fractions. Uroporphyrinogen I (Urogen I) and coproporphyrinogen I (Coprogen I) oxidase activities were found in all fractions; however, etioplast fractions had significantly more substrate specificity for protoporphyrinogen IX (Protogen IX) than the other fractions. Urogen I and Coprogen I oxidase activities were unaffected by AFM in all fractions, and 2 mM DTT almost completely inhibited these activities from all fractions. Diethyldithiocarbamate inhibited PM Protox activity by 62% but had less effect on microsome and little or no effect on etioplast Protox. juglone and duroquinone stimulated microsomal and PM Protox activity, whereas the lesser effect of these quinones on etioplast Protox activity was judged to be due to PM and/or microsomal contaminants. These data indicate that there are microsomal and PM Protogen IX-oxidizing activities that are not the same as those associated with the etioplast and that these activities are not inhibited i n vivo by AFM. In summary, these data support the view that the primary source of high protoporphyrin IX concentrations in AFM-treated plant tissues is from Protogen IX exported by plastids and oxidized by AFM-resistant extraorganellar oxidases.

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“…Due to the inhibition of the enzyme activity, protoporphyrinogen 1X accumulates in vivo. After its export from the plastids and nonspecific oxidation by herbicide-insensitive oxygenases in the plasma membrane (Lehnen et al, 1990;Jacobs and Jacobs, 1993), the resulting protoporphyrin IX undergoes rapid photooxidation. In the presence of O2 and light, protoporphyrin IX forms highly reactive oxygen radicals and singlet oxygen that damage membrane structures and ultimately lead to cell death (Jacobs and Jacobs, 1993).…”

Section: Biosynthesis Of Chlorophylls Hemes and Other Tetrapyrrolesmentioning

confidence: 99%

The Regulation of Enzymes Involved in Chlorophyll Biosynthesis

Reinbothe

1996

European Journal of Biochemistry

125

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All living organisms contain tetrapyrroles. In plants, chlorophyll (chlorophyll a plus chlorophyll b) is the most abundant and probably most important tetrapyrrole. It is involved in light absorption and energy transduction during photosynthesis. Chlorophyll is synthesized from the intact carbon skeleton of glutamate via the C, pathway. This pathway takes place in the chloroplast. It is the aim of this review to summarize the current knowledge on the biochemistry and molecular biology of the C,-pathway enzymes, their regulated expression in response to light, and the impact of chlorophyll biosynthesis on chloroplast development. Particular emphasis will be placed on the key regulatory steps of chlorophyll biosynthesis in higher plants, such as 5-aminolevulinic acid formation, the production of Mg*+-protoporphyrin IX, and light-dependent protochlorophyllide reduction.

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Tissue and cellular localization of acifluorfen-induced porphyrins in cucumber cotyledons

Cited by 75 publications

References 36 publications

Differential Accumulation of Protoporphyrin IX between Oxyfluorfen Resistant and Non-Resistant Soybean Cell Lines

Differential Accumulation of Protoporphyrin IX between Oxyfluorfen Resistant and Non-Resistant Soybean Cell Lines

Cellular Localization of Protoporphyrinogen-Oxidizing Activities of Etiolated Barley (Hordeum vulgare L.) Leaves (Relationship to Mechanism of Action of Protoporphyrinogen Oxidase-Inhibiting Herbicides)

The Regulation of Enzymes Involved in Chlorophyll Biosynthesis

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