psbA Mutation (valine219 to isoleucine) inPoa annua resistant to metribuzin and diuron

Mengistu, Lemma W.; Mueller‐Warrant, George W.; Liston, Aaron; Barker, Randolph

doi:10.1002/(sici)1526-4998(200003)56:3<209::aid-ps117>3.0.co;2-8

Cited by 87 publications

(79 citation statements)

References 35 publications

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“…2A). Note that none of the previously described tolerance-conferring mutations, resulting in amino acid substitutions at Ser 264 and Val 219 (9,51,53,55,62,68), was found in any of the psbA haplotypes.…”

Section: Resultsmentioning

confidence: 99%

“…Mutations in psbA have emerged in plants growing in environments contaminated by PS II inhibitors as a consequence of their selection pressures (reviewed in references 24 and 81). The mutations result in amino acid substitutions in or close to the herbicide-binding region of D1 in either of two positions, Ser 264 and Val 219 (9,51,53,55,62,68), which are thought to give tolerance through a reduced affinity of the herbicide to the Q B -binding niche (45,97). Whereas eukaryotes have only one or two copies of psbA per chloroplast genome (26,27), cyanobacteria have from two to five paralogous psbA genes (19,73,107).…”

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confidence: 96%

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Community-Level Analysis of psbA Gene Sequences and Irgarol Tolerance in Marine Periphyton

Eriksson

Clarke

Franzén

et al. 2009

Appl Environ Microbiol

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This study analyzes psbA gene sequences, predicted D1 protein sequences, species relative abundance, and pollution-induced community tolerance in marine periphyton communities exposed to the antifouling compound Irgarol 1051. The mechanism of action of Irgarol is the inhibition of photosynthetic electron transport at photosystem II by binding to the D1 protein. The metagenome of the communities was used to produce clone libraries containing fragments of the psbA gene encoding the D1 protein. Community tolerance was quantified with a short-term test for the inhibition of photosynthesis. The communities were established in a continuous flow of natural seawater through microcosms with or without added Irgarol. The selection pressure from Irgarol resulted in an altered species composition and an inducted community tolerance to Irgarol. Moreover, there was a very high diversity in the psbA gene sequences in the periphyton, and the composition of psbA and D1 fragments within the communities was dramatically altered by increased Irgarol exposure. Even though tolerance to this type of compound in land plants often depends on a single amino acid substitution (Ser 264 3Gly) in the D1 protein, this was not the case for marine periphyton species. Instead, the tolerance mechanism likely involves increased degradation of D1. When we compared sequences from low and high Irgarol exposure, differences in nonconserved amino acids were found only in the so-called PEST region of D1, which is involved in regulating its degradation. Our results suggest that environmental contamination with Irgarol has led to selection for high-turnover D1 proteins in marine periphyton communities at the west coast of Sweden.Development of tolerance, or resistance, to anthropogenic toxicants released into the environment is an issue of increasing importance. Reports of tolerant organisms are increasing, and tolerance toward a variety of compounds has been found (22,44,46,100). This is essentially evolution in action and shows that toxicants can act as selective pressures in the environment. Even though high concentrations of toxicants can be released in episodes or pulses, the overall environmental concentrations of toxicants are often quite low, which implies that adaptation and nonlethal selection are more common than acute and/or lethal effects.Since sensitivities to a given toxicant differ within species and even more so between species (12), a toxicant-induced succession (TIS) will occur in toxicant-exposed communities, where sensitive species, individuals, or genotypes are replaced by more tolerant ones, giving an increase in average tolerance in the community. This chain of events is fundamental for the pollution-induced community tolerance (PICT) concept (14). PICT studies can be performed in natural or model ecosystems and have the important advantage of a causal link between exposure and effect. The concept has been used to demonstrate long-term selection pressure from toxicants on several types of communities, as reviewed by Blanck (10) and...

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 96%

Community-Level Analysis of psbA Gene Sequences and Irgarol Tolerance in Marine Periphyton

Eriksson

Clarke

Franzén

et al. 2009

Appl Environ Microbiol

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“…As previously mentioned, electron transfer processes in the PS II reaction center of weeds with a mutation at position 264 were slowed and the ecological fitness of the mutants was reduced. In contrast, no effect on electron transfer in the PS II reaction center was found for the Poa annua mutant with the valine 219 to isoleucine change, and it was supposed that this mutant may be ecologically as fit as the wild type [29].…”

Section: Inhibitors Of Photosystem II (Ps Ii)mentioning

confidence: 99%

HRAC Classification of Herbicides and Resistance Development

Menne¹,

Köcher²

2011

Modern Crop Protection Compounds

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“…It has been reported that resistance to DCMU is often acquired by an alteration of the herbicidebinding site (D1 protein) on the thylakoid membranes, which results in a reduced affinity of the herbicide with the binding site (Galloway & Mets, 1984;Erickson et al, 1989;Galloway & Mets, 1989). DCMU-resistant mutants of higher plants and green algae were shown to involve single amino-acid substitutions in the D1 protein (Hirschberg & McIntosh, 1983;Hirschberg et al, 1987;Erickson et al, 1989;Mengistu et al, 2000Mengistu et al, , 2005. Such mutants usually present additional pleiotropic effects, such as an increased sensitivity to strong illumination (Sundby et al, 1993;Alfonso et al, 1996), tolerance to irradiance (Singh & Singh, 1997), tolerance to heat stress (Alfonso et al, 2001) and tolerance to salt stress (Singh & Kshatriya, 2002).…”

Section: Introductionmentioning

confidence: 99%

DCMU-resistance mutation confers resistance to high salt stress in the red microalgaPorphyridiumsp. (Rhodophyta)

Manandhar-Shrestha

Arad

Vonshak

2009

European Journal of Phycology

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The response of photosynthesis to salinity stress in wild-type and DCMU-resistant (strain DC-2) Porphyridium sp. was investigated. Both wild-type and DC-2 were able to acclimate and establish a new steady state of growth when exposed to salt stress, but growth rate of the DC-2 mutant strain was 1.25-fold higher than growth rate of wild-type cells. Following establishment of a new steady state under the salt stress conditions, the maximal irradiance-saturated photosynthetic capacity (P max ), light saturation (I k ) and the photosynthetic efficiency () were 1.5-, 1.8-and 1.1-fold, respectively, higher in the DC-2 mutant cells than wild-type. Furthermore, salt-stressed DC-2 mutant cells exhibited 1.6-fold higher maximal efficiency of PS II (Fv/Fm) after 200 min exposure and 3-fold higher level of D1 protein after 24 h exposure to salt than wild-type cells. Exposing the salt-stressed cells to high photon flux density (3000 mmol m -2 s -1 ) for 1 h resulted in a higher resistance of mutant cells than wild-type to light stress, as reflected in 1.3-fold decline in the Fv/Fm. This finding corresponds well with the levels of the D1 protein measured in the cells. These observations indicate that the D1 protein of the PS II apparatus in the DC-2 mutant was more resistant to stress. However, under non-stressed (light and salt) conditions, no differences were observed between wild-type and the DC-2 mutant cells for all the parameters studied. The DC-2 mutant responded better than wild-type to environmental stresses, namely salinity and light due to the modification induced in PS II.

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psbA Mutation (valine219 to isoleucine) inPoa annua resistant to metribuzin and diuron

Cited by 87 publications

References 35 publications

Community-Level Analysis of psbA Gene Sequences and Irgarol Tolerance in Marine Periphyton

Community-Level Analysis of psbA Gene Sequences and Irgarol Tolerance in Marine Periphyton

HRAC Classification of Herbicides and Resistance Development

DCMU-resistance mutation confers resistance to high salt stress in the red microalgaPorphyridiumsp. (Rhodophyta)

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