Relationship between inhibitor binding by chloroplasts and inhibition of photosynthetic electron transport

Tischer, Wolfgang; Strotmann, Heinrich

doi:10.1016/0005-2728(77)90157-8

Cited by 361 publications

(202 citation statements)

References 22 publications

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“…The concentration of PSII reaction centers was determined by measuring the specific binding of ['4C]atrazine to the high affinity site on thylakoid membranes (30). Cyt f content was determined from reduced (hydroquinone) minus oxidized (potassium ferricyanide) difference spectra using an extinction coefficient of 18 mM-' cm-' (20).…”

Section: Analysis Of Thylakoid Membrane Componentsmentioning

confidence: 99%

“…Uncoupled photosynthetic electron transport was assayed as DCIP reduction at 580 nm (E580 = 18.0 mM-' cm-') with water as the electron donor (21). The assay contained 0.1 M sorbitol, 40 mM Tricine-NaOH (pH 8.0), 1 mm NH4Cl, 30 ,gM DCIP, and 2 Ag Chl/ml. Saturating actinic light was passed through a red filter (Corning 2-58) and the detector was protected with a blue filter (Coming 4-96).…”

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confidence: 99%

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Response of Soybean Photosynthesis and Chloroplast Membrane Function to Canopy Development and Mutual Shading

Burkey

Wells²

1991

Plant Physiol.

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The effect of natural shading on photosynthetic capacity and chloroplast thylakoid membrane function was examined in soybean (Glycine max. cv Young) under field conditions using a randomized complete block design. Seedlings were thinned to 15 plants per square meter at 20 days after planting. Leaves destined to function in the shaded regions of the canopy were tagged during early expansion at 40 days after planting. To investigate the response of shaded leaves to an increase in available light, plants were removed from certain plots at 29 or 37 days after tagging to reduce the population from 15 to three plants per square meter and alter the irradiance and spectral quality of light. During the transition from a sun to a shade environment, maximum photosynthesis and chloroplast electron transport of control leaves decreased by two-to threefold over a period of 40 days followed by rapid senescence and abscission. Senescence and abscission of tagged leaves were delayed by more than 4 weeks in plots where plant populations were reduced to three plants per square meter. Maximum photosynthesis and chloroplast electron transport activity were stabilized or elevated in response to increased light when plant populations were reduced from 15 to three plants per square meter. Several chloroplast thylakoid membrane components were affected by light environment. Cytochrome f and coupling factor protein decreased by 40% and 80%, respectively, as control leaves became shaded and then increased when shaded leaves acclimated to high light. The concentrations of photosystem I (PSI) and photosystem 11 (PSII) reaction centers were not affected by light environment or leaf age in field grown plants, resulting in a constant PSII/PSI ratio of 1.6 ± 0.3. Analysis of the chlorophyll-protein composition revealed a shift in chlorophyll from PSI to PSII as leaves became shaded and a reversal of this process when shaded leaves were provided with increased light. These results were in contrast to those of soybeans grown in a growth chamber where the PSII/ PSI ratio as well as cytochrome f and coupling factor protein levels were dependent on growth irradiance. To summarize, light environment regulated both the photosynthetic characteristics and the timing of senescence in soybean leaves grown under field conditions. ' Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the United States Department of Agriculture or the North Carolina Agricultural Research Service and does not imply its approval to the exclusion of other products that may also be suitable.Both light quantity and light quality regulate the photosynthetic properties of higher plants by controlling the activity and the composition of the photosynthetic apparatus (2, 5, 29). Thus, light environment plays a critical role during leaf expansion in determining the photosynthetic properties of the mature leaf. More recently, controlled environment studies with a number of species have shown that fully expanded leaves reta...

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Section: Analysis Of Thylakoid Membrane Componentsmentioning

confidence: 99%

mentioning

confidence: 99%

Response of Soybean Photosynthesis and Chloroplast Membrane Function to Canopy Development and Mutual Shading

Burkey

Wells²

1991

Plant Physiol.

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“…DCMU, or diuron, is a potent member of the urea class, and atrazine is a potent and widely used triazine. In addition to having nearly identical physiological effects, these various herbicides show competitive binding to the same site on the thylakoid membrane (29). All of the herbicides share the common structural feature of a sp2 hybrid orbital carbon bonded to a nitrogen atom (9).…”

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confidence: 99%

Non-Mendelian Inheritance of 3-(3,4-Dichlorophenyl)-1,1-dimethylurea-Resistant Thylakoid Membrane Properties in Chlamydomonas

Galloway

Mets²

1982

Plant Physiol.

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A uniparentally inherited 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU)-resistant mutant of Chiamydomonas reinhardii, Dr2, which has a resistance mechanism of the type defined as 'primary,' has been isolated. In vitro Hill reactions catalyzed by isolated thylakoid membranes reveal a reduced apparent affinity of the thylakoids for DCMU. These changes in membrane properties quantitatively account for the resistance of mutant Dr2 to herbicide inhibition of growth. There are several chemically distinct classes of herbicides which inhibit photosynthesis by blocking electron transport away from the reduced PSII acceptor, Q (20). DCMU, or diuron, is a potent member of the urea class, and atrazine is a potent and widely used triazine. In addition to having nearly identical physiological effects, these various herbicides show competitive binding to the same site on the thylakoid membrane (29). All of the herbicides share the common structural feature of a sp2 hybrid orbital carbon bonded to a nitrogen atom (9). At the same time, studies of substituent effects on the binding of different chemical classes show that one class may have important contacts with the binding site which are in a different spatial domain from some of the contacts which are important to a different class. Thus, it seems that each chemical class of these herbicides shares a portion of its binding site with all of the others, but that a portion is specific for that class (2).The derivative of atrazine which retains competitive binding to this site becomes covalently bonded to a 32,000 D thylakoid membrane polypeptide when the complex is UV irradiated (6). The reaction of this protein is dependent upon specific binding at the site, since it cannot be labeled in thylakoids from an atrazine-resistant biotype of Amaranthus which do not bind atrazine (23). Thus, this 32,000 D polypeptide is either part of or close to the binding site, but it is not known whether this part is shared with other herbicides or whether it interacts uniquely with triazines. Mattoo et al. (16) have shown that a 32,000 D polypeptide of Spirodela thylakoids, which is ordinarily quite sensitive to trypsin treatment of the membranes, is rendered resistant to digestion upon DCMU binding. If this protein is homologous with the azido-atrazine labeled protein, then it is apparent that it has important interactions with both triazines and ureas. Oettmeier et al. (21) found that an azido derivative of dinoseb (a dinitrophenol) acted as a photoaffinity label for a spinach thylakoid membrane polypeptide in the 40,000 D range. If this protein is not homologous to the atrazine-labeled protein, then one must conclude that the binding sites for the different classes of herbicides reach into the region of at least two proteins. It will be of interest to determine if herbicide resistance can arise from mutations in more than one thylakoid protein gene.We have initiated a study of resistance to DCMU in Chlamydomonas reinhardii with two main objectives (a) By using genetic variants, we hop...

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“…Its binding behaviour exhibits the same characteristics, specific and unspecific binding, like other photosystem II inhibitors [17,18]. A binding constant Kb = 0.14 (+ 0.02 ) FM (corresponding to a p& of 6.87 ( + 0.06) has been determined, which corresponds well to the p&o value of 6.4 (the latter is not extrapolated to zero chlorophyll concentration).…”

Section: Resultsmentioning

confidence: 68%

Anthraquinone inhibitors of photosystem II electron transport

1988

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Various substituted 9,10-anthraquinones were tested for their inhibitory activity on photosystem II electron transport. Maximal inhibitory activity was achieved if the positions adjacent to one of the quinone carbonyl groups were unsubstituted or substituted by hydroxyl groups only. The best anthraquinone type inhibitor found so far was 2,3,4-trichloro-lhydroxy-anthraquinone with a pl,, value of 7.75. This is well comparable to the most powerful known photosystem II

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Relationship between inhibitor binding by chloroplasts and inhibition of photosynthetic electron transport

Cited by 361 publications

References 22 publications

Response of Soybean Photosynthesis and Chloroplast Membrane Function to Canopy Development and Mutual Shading

Response of Soybean Photosynthesis and Chloroplast Membrane Function to Canopy Development and Mutual Shading

Non-Mendelian Inheritance of 3-(3,4-Dichlorophenyl)-1,1-dimethylurea-Resistant Thylakoid Membrane Properties in Chlamydomonas

Anthraquinone inhibitors of photosystem II electron transport

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