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Genome‐wide study of glutathione transferases and their regulation in flufenacet susceptible and resistant black‐grass ( Alopecurus myosuroides Huds.)
No full textAbstract
BACKGROUND
Glutathione transferases (GSTs) are enzymes with a wide range of functions, including herbicide detoxification. Up‐regulation of GSTs and their detoxification activity enables the grass weed black‐grass (
Alopecurus myosuroides
Huds.) to metabolize the very‐long‐chain fatty acid synthesis inhibitor flufenacet and other herbicides leading to multiple herbicide resistance. However, the genomic organization and regulation of GSTs genes is still poorly understood.
RESULTS
In this genome‐wide study the location and expression of 115 GSTs were investigated using a recently published black‐grass genome. Particularly, the most abundant GSTs of class tau and phi were typically clustered and often followed similar expression patterns but possessed divergent upstream regulatory regions. Similarities were found in the promoters of the most up‐regulated GSTs, which are located next to each other in a cluster. The binding motif of the E2F/DP transcription factor complex in the promoter of an up‐regulated GST was identical in susceptible and resistant plants, however, adjacent sequences differed. This led to a stronger binding of proteins to the motif of the susceptible plant, indicating repressor activity.
CONCLUSIONS
This study constitutes the first analysis dealing with the genomic investigation of GST genes found in black‐grass and their transcriptional regulation. It highlights the complexity of the evolution of GSTs in black‐grass, their duplication and divergence over time. The large number of GSTs allows weeds to detoxify a broad spectrum of herbicides. Ultimately, more research is needed to fully elucidate the regulatory mechanisms of GST expression. © 2024 The Authors.
Pest Management Science
published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.Bayer https://doi.org/10.13039/10000432
Flufenacet activity is affected by GST inhibitors in blackgrass ( Alopecurus myosuroides ) populations with reduced flufenacet sensitivity and higher expression levels of GSTs
No full textAn intronless tau class glutathione transferase detoxifies several herbicides in flufenacet resistant ryegrass
No full textAbstract Resistance to pre-emergence herbicides, e.g., inhibitors of the biosynthesis of very-long-chain fatty acids (VLCFAs), is evolving in response to increased use of these compounds. Grass weeds such as ryegrasses (Lolium spp.) have accumulated resistance to various herbicide modes of action. Here, an RNA-Seq analysis was conducted using three ryegrass populations resistant to the VLCFA biosynthesis inhibitor flufenacet to investigate this phenomenon. Besides various transcripts, including putative long non-coding RNAs (lncRNAs), a single putatively functional tau class glutathione transferase (GST) was constitutively differentially expressed. It was further induced by herbicide application. This GST was expressed as a recombinant protein in Escherichia coli along with other GSTs and detoxified flufenacet rapidly in vitro. Detoxification rates of other herbicides tested in vitro were in accordance with cross-resistance patterns previously determined in vivo. A genome-wide GST analysis revealed that the candidate GST was located in a cluster of three intronless GSTs. Their intronless nature possibly results from the retroposition of cellular mRNAs followed by tandem duplication and may affect gene expression. The large number of GSTs (≥ 195) in the genome of rigid ryegrass (L. rigidum) compared to other plant organisms is likely a key factor in the ability of this weed to evolve resistance to different herbicide chemistries. However, in the case of flufenacet resistance, a single upregulated GST with high affinity for the substrate flufenacet possibly contributes over-proportionally to rapid herbicide detoxification in planta. The regulation of this gene and the role of differentially expressed transcripts, including various putative lncRNAs, require further investigation
Huds.) field populations
No full textBlack-grass (Alopecurus myosuroides Huds.) is a frequent grass weed that commonly occurs in winter wheat in temperate Europe. Evolving resistance to post-emergence herbicides, e.g. acetyl CoA carboxylase (ACCase) and acetolactate synthase (ALS) inhibitors requires more complex weed management strategies and ensuring good efficacy of pre-emergence treatments becomes increasingly important. Flufenacet, in particular, has become a key herbicide for the control of multiple-resistant A. myosuroides. However, in some of those populations, reduced flufenacet efficacy was already observed
spp.) field populations
No full textHerbicides inhibiting the synthesis of very long-chain fatty acids (HRAC group K3 , WSSA group 15), such as flufenacet, play an important role in weed management strategies, particularly when herbicide resistance to inhibitors with other modes of action, such as acetolactate synthase or acetyl coenzyme A carboxylase (ACCase), has already evolved. So far, only a few cases of resistance towards inhibitors of the synthesis of very long-chain fatty acids have been described. In this study, we characterized the level of flufenacet resistance in several Lolium spp. field populations and investigated the resistance mechanism
Huds.) form different flufenacet metabolites and differ in their interaction with pre‐ and post‐emergence herbicides
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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