Amino Acid Substitutions in the Acetolactate Synthase Gene of Red Rice (Oryza sativa) Confer Resistance to Imazethapyr

Weed Science ◽  
2008 ◽  
Vol 56 (4) ◽  
pp. 485-489 ◽  
Author(s):  
Marites A. Sales ◽  
Vinod K. Shivrain ◽  
Nilda R. Burgos ◽  
Yong I. Kuk
Keyword(s):  
Amino Acid ◽  
Conformational Changes ◽  
Weed Management ◽  
Acetolactate Synthase ◽  
Management Program ◽  
Amino Acid Substitutions ◽  
Red Rice ◽  
Cultivated Rice ◽  
Sequence Alignments ◽  
Geographical Regions

Two red rice accessions from Arkansas have been found to be resistant to the labeled rate of imazethapyr, which is used to control red rice in ClearfieldTMrice. Full-length amplification of the acetolactate synthase (ALS) gene in imazethapyr-resistant red rice revealed a coding sequence of 1,935 base pairs, which is the same as that of the cultivated rice. Coding sequences were generated from four red rice accessions collected from different geographical regions in Arkansas, consisting of accessions that were either resistant or susceptible to imazethapyr. Nucleotide sequence alignments identified six base polymorphisms, three of which resulted in amino acid substitutions in theALSgene. One amino acid substitution, Gly654Glu, involves a residue required for imazethapyr binding to the ALS. The other substitution, Val669Met, implies conformational changes in the ALS structure that enhances binding of thiamine diphosphate, an ALS cofactor. These novel amino acid substitutions first reported for ALS-resistant red rice accessions support the hypothesis that ALS-resistant red rice can evolve with sustained herbicide selection pressure. Thus, it behooves growers to integrate the Cleafield rice technology with other tools to achieve a successful, long-term weed management program.

Effectiveness of Herbicides for Control of Hairy Vetch (Vicia villosa) in Winter Wheat

2015 ◽  
Vol 29 (3) ◽  
pp. 509-518 ◽  
Author(s):  
William S. Curran ◽  
John M. Wallace ◽  
Steven Mirsky ◽  
Benjamin Crockett
Keyword(s):  
Winter Wheat ◽  
Weed Management ◽  
Acetolactate Synthase ◽  
Oxidase Inhibitor ◽  
Management Program ◽  
Integrated Weed Management ◽  
Hairy Vetch ◽  
Synthetic Auxins ◽  
Als Inhibitors ◽  
Tribenuron Methyl

A field experiment was conducted in 2009–2010 at Pennsylvania and Maryland locations, and repeated it in 2010–2011 to test the effectiveness of POST-applied herbicides at fall and spring timings on seeded hairy vetch in winter wheat. A total of 16 herbicide treatment combinations was tested that included synthetic auxins, acetolactate synthase (ALS) inhibitors, and a protoporphyrinogen oxidase inhibitor. Spring applications tended to be more effective than fall applications. Among synthetic auxins, clopyralid (105 g ae ha−1) and treatments containing dicamba (140 g ae ha−1) were effective at both timings, resulting in greater than 90% hairy vetch control at wheat harvest. Pyroxsulam and prosulfuron applied at 18 g ai ha−1 provided the most effective hairy vetch control (> 90%) at both application timings among ALS inhibitors. Spring applications of several herbicides provided moderate (> 80%) to high (> 90%) levels of hairy vetch control, including: 2,4-D amine (140 g ae ha−1), mesosulfuron-methyl (15 g ai ha−1), tribenuron-methyl (13 g ai ha−1), and thifensulfuron/tribenuron-methyl treatments (16 and 32 g ai ha−1). Winter wheat injury was evaluated, but symptoms were negligible for most treatments. Winter wheat yields declined with increasing hairy vetch biomass. Fall herbicides may be prioritized to reduce hairy vetch competition during the fall and early spring growing season. Our research has established that several synthetic auxin and ALS-inhibiting herbicides, applied POST in fall or spring, can be safely used in winter wheat to control hairy vetch in an integrated weed management program.

scholarly journals CRISPR/Cas9-Mediated Multi-Allelic Gene Targeting in Sugarcane Confers Herbicide Tolerance

2021 ◽  
Vol 3 ◽  
Author(s):  
Mehmet Tufan Oz ◽  
Angelika Altpeter ◽  
Ratna Karan ◽  
Aldo Merotto ◽  
Fredy Altpeter
Keyword(s):  
Amino Acid ◽  
Gene Targeting ◽  
Crop Improvement ◽  
Herbicide Tolerance ◽  
Acetolactate Synthase ◽  
Amino Acid Substitutions ◽  
Dna Double Strand Breaks ◽  
Nucleotide Substitutions ◽  
Multiple Alleles ◽  
Homology Directed Repair

Sugarcane is the source of 80% of the sugar and 26% of the bioethanol produced globally. However, its complex, highly polyploid genome (2n = 100 – 120) impedes crop improvement. Here, we report efficient and reproducible gene targeting (GT) in sugarcane, enabling precise co-editing of multiple alleles via template-mediated and homology-directed repair (HDR) of DNA double strand breaks induced by the programmable nuclease CRISPR/Cas9. The evaluation of 146 independently transformed plants from five independent experiments revealed a targeted nucleotide replacement that resulted in both targeted amino acid substitutions W574L and S653I in the acetolactate synthase (ALS) in 11 lines in addition to single, targeted amino acid substitutions W574L or S653I in 25 or 18 lines, respectively. Co-editing of up to three ALS copies/alleles that confer herbicide tolerance was confirmed by Sanger sequencing of cloned long polymerase chain reaction (PCR) amplicons. This work will enable crop improvement by conversion of inferior alleles to superior alleles through targeted nucleotide substitutions.

scholarly journals Impact of Amino Acid Substitutions in Region II and Helix K of HSV-1 and HCMV DNA Polymerases on Resistance to Foscarnet

2021 ◽  
Author(s):  
Karima Zarrouk ◽  
Xiaojun Zhu ◽  
Van Dung Pham ◽  
Nathalie Goyette ◽  
Jocelyne Piret ◽  
...  
Keyword(s):  
Amino Acid ◽  
Conformational Changes ◽  
Recombinant Dna ◽  
Three Dimensional ◽  
Amino Acid Substitutions ◽  
Herpes Simplex Virus 1 ◽  
Simplex Virus ◽  
The Impact ◽  
Region Ii ◽  
Hsv 1

Amino acid substitutions conferring resistance of herpes simplex virus 1 (HSV-1) and human cytomegalovirus (HCMV) to foscarnet (PFA) are respectively located in UL30 and UL54 genes encoding the DNA polymerase (pol). In this study, we analyzed the impact of substitutions located in helix K and region II that are involved in the conformational changes of the DNA pol. Theoretical substitutions were identified by sequences alignment of the helix K and region II of human herpesviruses (susceptible to PFA) and bacteriophages (resistant to PFA) and introduced in viral genomes by recombinant phenotyping. We characterized the susceptibility of HSV-1 and HCMV mutants to PFA. In UL30, substitutions I619K (helix K), V715S and A719T (both in region II) increased mean PFA EC50 by 2.5-, 5.6- and 2.0-fold compared to wild type (WT), respectively. In UL54, substitution Q579I (helix K) conferred hypersusceptibility to PFA (0.17-fold change) whereas substitutions Q697P, V715S and A719T (all in region II) increased mean PFA EC50 values by 3.8-, 2.8- and 2.5-fold compared to WT, respectively. These results were confirmed by enzymatic assays using recombinant DNA pol harboring these substitutions. Three-dimensional modeling suggests that substitutions conferring resistance/hypersusceptibility to PFA located in helix K and region II of UL30 and UL54 DNA pol favor an open/closed conformation of these enzymes resulting in a lower/higher drug affinity for the proteins. Thus, this study shows that both regions of UL30 and UL54 DNA pol are involved in the conformational changes of these proteins and can influence the susceptibility of both viruses to PFA.

scholarly journals The amino acids that constitute sequence gamma 268-282 of fibrinogen are not involved in fibrin monomer polymerization.

1993 ◽  
Vol 40 (4) ◽  
pp. 515-520
Author(s):  
A Janiak ◽  
T Plucinski ◽  
G Kupryszewski ◽  
C S Cierniewski
Keyword(s):  
Amino Acid ◽  
Conformational Changes ◽  
Single Amino Acid ◽  
Amino Acid Substitutions ◽  
Peptide Fragment ◽  
Specific Antibodies ◽  
Fibrin Monomer ◽  
Fibrin Monomers ◽  
Peptide Region

Congenitally abnormal fibrinogens with impaired fibrin monomer polymerization have been described to contain single amino-acid substitutions localized in certain positions of the gamma 275-330 peptide region. To evaluate the role of the amino-acid sequence in the vicinity of Arg275 in fibrin monomer polymerization, the peptide fragment corresponding to gamma 268-282 was synthesized and used to obtain peptide-specific antibodies. These antibodies, when purified immunochemically on the immobilized peptide, bound to the intact fibrinogen and fibrin monomers with the same binding affinity. However, they did not recognize the gamma 268-282 epitopes on the denatured and reduced fibrinogen molecules. The lack of influence of antipeptide antibodies on fibrin monomer polymerization indicates that the gamma 268-282 peptide is not directly involved in the structure of the polymerization site in the D domain of fibrinogen. It is suggested that substitution of Arg275 either by His or Cys in abnormal fibrinogens results probably in conformational changes which disturb a proper orientation of the polymerization site and reduce its expression.

scholarly journals Two residues in the extracellular domain convert a nonfunctional ASIC1 into a proton-activated channel

2010 ◽  
Vol 299 (1) ◽  
pp. C66-C73 ◽  
Author(s):  
Tianbo Li ◽  
Youshan Yang ◽  
Cecilia M. Canessa
Keyword(s):  
Amino Acid ◽  
Conformational Changes ◽  
Transmembrane Helix ◽  
Amino Acid Substitutions ◽  
Fast Kinetics ◽  
Acid Sensing Ion Channels ◽  
Inward Currents ◽  
Mammalian Counterpart ◽  
Opening And Closing ◽  
Kinetics Of

Acid-sensing ion channels (ASICs) are proton-activated sodium channels of the nervous system. Mammals express four ASICs, and orthologs of these genes have been found in all chordates examined to date. Despite a high degree of sequence conservation of all ASICs across species, the response to a given increase in external proton concentration varies markedly: from large and slowly inactivating inward currents to no detectable currents. The underlying bases of this functional variability and whether it stems from differences in proton-binding sites or in structures that translate conformational changes have not been determined yet. We show here that the ASIC1 ortholog of an early vertebrate, lamprey ASIC1, does not respond to protons; however, only two amino acid substitutions for the corresponding ones in rat ASIC1, Q77L and T85L, convert lamprey ASIC1 into a highly sensitive proton-activated channel with apparent H+ affinity of pH50 7.2. Addition of C73H increases the magnitude of the currents by fivefold, and W64R confers desensitization similar to that of the mammalian counterpart. Most amino acid substitutions in these four positions increase the rates of opening and closing the pore, whereas only few, namely, the ones in rat ASIC1, slow the rates. The four residues are located in a contiguous segment made by the β1-β2-linker, β1-strand, and the external segment of the first transmembrane helix. We conclude that the segment thus defined modulates the kinetics of opening and closing the pore and that fast kinetics of desensitization rather than lack of acid sensor accounts for the absence of proton-induced currents in the parent lamprey ASIC1.

Imazethapyr plus Residual Herbicide Programs for Imidazolinone-Resistant Rice

2012 ◽  
Vol 26 (3) ◽  
pp. 410-416 ◽  
Author(s):  
Eric P. Webster ◽  
Tyler P. Carlson ◽  
Michael E. Salassi ◽  
Justin B. Hensley ◽  
David C. Blouin
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Residual Activity ◽  
Field Studies ◽  
Management Program ◽  
Red Rice ◽  
Initial Application ◽  
Residual Herbicide ◽  
Herbicide Programs

Field studies were conducted in 2008 and 2009 near Crowley, LA to evaluate the addition of a herbicide with soil-residual activity in mixture with imazethapyr applied very early POST followed by an application of imazethapyr or imazamox 2 wk after the initial application. Weeds evaluated included red rice, barnyardgrass, and alligatorweed. Weed control with treatments including a herbicide with soil-residual activity was equivalent to or higher than imazethapyr applied alone followed by imazethapyr or imazamox. Yield and economical returns were maximized with quinclorac or penoxsulam mixed with imazethapyr followed by imazethapyr or imazamox. The addition of quinclorac or penoxsulam proved to be beneficial in a total weed management program.

Weed Management Practices and Needs in Arkansas and Mississippi Rice

2013 ◽  
Vol 27 (3) ◽  
pp. 623-630 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Jason Bond ◽  
Robert C. Scott
Keyword(s):  
Weed Management ◽  
Management Practices ◽  
Management Strategies ◽  
Mail Survey ◽  
Acetolactate Synthase ◽  
Palmer Amaranth ◽  
Red Rice ◽  
Rice Varieties ◽  
Herbicide Resistant ◽  
Control Options

Crop consultants in Arkansas and Mississippi were sent a direct-mail survey in fall of 2011 with questions concerning weed management in rice. The goal of the survey was to document the extent of imidazoline-resistant rice hectares, the herbicides most commonly recommended in rice, the weeds perceived to be most troublesome in rice including those resistant to herbicides, and suggested areas of research and educational focus that would improve weed management in rice. When appropriate, results from this survey were compared to a similar survey conducted in 2006. Completed rice surveys were returned by 43 consultants, accounting for 179,500 ha of scouted rice or 38% of the rice hectarage in Arkansas and Mississippi. Imidazolinone-resistant rice was grown on 64% of the hectares, and this technology was used continually for the past 5 yr on 11% of the rice hectares. Of the area planted to imidazolinone-resistant rice, 42% of this hectarage was treated solely with an acetolactate synthase (ALS)-inhibiting herbicide. Consultants listed improved control options for barnyardgrass and Palmer amaranth as the most important research and educational need in rice. The top five weeds in order of importance were (1) barnyardgrass, (2) sprangletops, (3) red rice, (4) northern jointvetch, and (5) Palmer amaranth. From a predetermined list of research and educational topics, consultants gave the highest ratings of importance to (1) control of herbicide-resistant weeds, (2) strategies to reduce the occurrence and spread of herbicide-resistant weeds, and (3) development of new economical herbicide-resistant rice varieties which was comparable to economical weed control options. Findings from this survey point to the overuse of imidazolinone-resistant rice and a lack of preemptive resistance management strategies such as crop rotation and use of multiple effective herbicide modes of action by some growers, which has likely contributed to selection for the ALS-resistant barnyardgrass and rice flatsedge recently confirmed in Arkansas and Mississippi rice.

Lessons Learned From the History of Herbicide Resistance

Weed Science ◽  
2014 ◽  
Vol 62 (2) ◽  
pp. 427-431 ◽  
Author(s):  
Dale L. Shaner
Keyword(s):  
Herbicide Resistance ◽  
Weed Management ◽  
Management System ◽  
Rapid Evolution ◽  
Acetolactate Synthase ◽  
Management Program ◽  
Lessons Learned ◽  
Triazine Resistance ◽  
Herbicide Resistant ◽  
Selection Of

The selection of herbicide-resistant weed populations began with the introduction of synthetic herbicides in the late 1940s. For the first 20 years after introduction, there were limited reported cases of herbicide-resistant weeds. This changed in 1968 with the discovery of triazine-resistant common groundsel. Over the next 15 yr, the cases of herbicide-resistant weeds increased, primarily to triazine herbicides. Although triazine resistance was widespread, the resistant biotypes were highly unfit and were easily controlled with specific alternative herbicides. Weed scientists presumed that this would be the case for future herbicide-resistant cases and thus there was not much concern, although the companies affected by triazine resistance were somewhat active in trying to detect and manage resistance. It was not until the late 1980s with the discovery of resistance to Acetyl Co-A carboxylase (ACCase) and acetolactate synthase (ALS) inhibitors that herbicide resistance attracted much more attention, particularly from industry. The rapid evolution of resistance to these classes of herbicides affected many companies, who responded by first establishing working groups to address resistance to specific classes of herbicides, and then by formation of the Herbicide Resistance Action Committee (HRAC). The goal of these groups, in cooperation with academia and governmental agencies, was to act as a forum for the exchange of information on herbicide-resistance selection and to develop guidelines for managing resistance. Despite these efforts, herbicide resistance continued to increase. The introduction of glyphosate-resistant crops in the 1995 provided a brief respite from herbicide resistance, and farmers rapidly adopted this relatively simple and reliable weed management system based on glyphosate. There were many warnings from academia and some companies that the glyphosate-resistant crop system was not sustainable, but this advice was not heeded. The selection of glyphosate resistant weeds dramatically changed weed management and renewed emphasis on herbicide resistance management. To date, the lesson learned from our experience with herbicide resistance is that no herbicide is invulnerable to selecting for resistant biotypes, and that over-reliance on a weed management system based solely on herbicides is not sustainable. Hopefully we have learned that a diverse weed management program that combines multiple methods is the only system that will work for the long term.

Recombinant Variants of Tissue-Type Plasminogen Activator Containing Amino Acid Substitutions in the Finger Domain

1992 ◽  
Vol 68 (06) ◽  
pp. 672-677 ◽  
Author(s):  
Hitoshi Yahara ◽  
Keiji Matsumoto ◽  
Hiroyuki Maruyama ◽  
Tetsuya Nagaoka ◽  
Yasuhiro Ikenaka ◽  
...  
Keyword(s):  
Amino Acid ◽  
Plasminogen Activator ◽  
Half Life ◽  
Tissue Type ◽  
Clot Lysis ◽  
Amino Acid Substitutions ◽  
Wild Type ◽  
Plasma Clot ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator

SummaryTissue-type plasminogen activator (t-PA) is a fibrin-specific agent which has been used to treat acute myocardial infarction. In an attempt to clarify the determinants for its rapid clearance in vivo and high affinity for fibrin clots, we produced five variants containing amino acid substitutions in the finger domain, at amino acid residues 7–9, 10–14, 15–19, 28–33, and 37–42. All the variants had a prolonged half-life and a decreased affinity for fibrin of various degrees. The 37–42 variant demonstrated about a 6-fold longer half-life with a lower affinity for fibrin. Human plasma clot lysis assay estimated the fibrinolytic activity of the 37–42 variant to be 1.4-fold less effective than that of the wild-type rt-PA. In a rabbit jugular vein clot lysis model, doses of 1.0 and 0.15 mg/kg were required for about 70% lysis in the wild-type and 37–42 variant, respectively. Fibrinogen was degraded only when the wild-type rt-PA was administered at a dose of 1.0 mg/kg. These findings suggest that the 37–42 variant can be employed at a lower dosage and that it is a more fibrin-specific thrombolytic agent than the wild-type rt-PA.

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