scholarly journals Genetic Variability of Acetolactate Synthase (ALS) Sequence in Centaurea cyanus Plants Resistant and Susceptible to Tribenuron-Methyl

Agronomy ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2311
Author(s):  
Barbara Wrzesińska ◽  
Tadeusz Praczyk
Keyword(s):  
Amino Acid ◽  
Genetic Variability ◽  
Amino Acid Sequence ◽  
Herbicide Resistance ◽  
Resistance Mechanism ◽  
Acetolactate Synthase ◽  
Sequence Information ◽  
Sequence Variability ◽  
Centaurea Cyanus ◽  
Tribenuron Methyl

Centaurea cyanus, belonging to the Asteraceae family, is an arable weed species encountered mainly in fields with cereals, sugar beet, and maize. The high genetic variability of C. cyanus has been recently reported; however, little is known about its sequence variability in the context of its herbicide resistance. C. cyanus resistance was found mainly against acetolactate synthase (ALS) inhibitors, but no ALS sequence information concerning the herbicide resistance mechanism has been published yet. The aim of this study was to determine the ALS sequences for biotypes susceptible and resistant to tribenuron-methyl in order to identify mutations that may be associated with the resistance emergence. DNA isolation from susceptible and resistant plants was followed by PCR amplification and ALS sequencing. As a result, different lengths of DNA products were obtained. Moreover, both nucleotide and amino acid sequence analysis revealed high sequence variability within one plant as well as between plants from the same biotype. In a few resistant plants, four changes in the amino acid sequence were identified in comparison to those in the susceptible ones. However, these preliminary studies require further investigation toward confirming the significance of these mutations in herbicide resistance development. This study provides preliminary information contributing to the research on the C. cyanus target-site resistance mechanism.

scholarly journals Genetic Variability of Acetolactate Synthase (ALS) Sequence in Centaurea Cyanus Plants Resistant and Susceptible to Tribenuron-methyl

2021 ◽  
Author(s):  
Barbara Wrzesinska ◽  
Tadeusz Praczyk ◽  
Aleksandra Obrępalska-Stęplowska
Keyword(s):  
Amino Acid ◽  
Genetic Variability ◽  
Amino Acid Sequence ◽  
Herbicide Resistance ◽  
Resistance Mechanism ◽  
Sequence Information ◽  
Sequence Variability ◽  
Centaurea Cyanus ◽  
Arable Weed ◽  
Tribenuron Methyl

Abstract Centaurea cyanus, belonging to the Asteraceae family, is an arable weed species being encountered mainly in the fields with cereals, sugar beet, and corn. C. cyanus high genetic variability has recently been reported, however, little is known about sequence variability in the context of herbicide resistance. C. cyanus resistance was found mainly against acetolactate inhibitors (ALS) inhibitors, but no ALS sequence information concerning herbicide resistance mechanism has been published yet. Therefore, the aim of this study was to determine ALS sequences for biotypes susceptible and resistant to tribenuron-methyl in order to identify possible mutations conferring the resistance. DNA isolation from susceptible and resistant plants was followed by PCR amplification and sequencing of ALS sequence. As a result different lengths of DNA products were obtained. Moreover, both nucleotide and amino acid sequence analysis revealed high sequence variability within one plant as well as between plants from the same biotype. In a few resistant plants, six changes in amino acid sequence were identified in comparison to susceptible ones. However, these preliminary studies require further investigation toward confirming the significance of these mutations in herbicide resistance development. This study provides the first attempt in the research on C. cyanus target-site resistance mechanism.

Acetolactate Synthase Gene Proline (197) Mutations Confer Tribenuron-Methyl Resistance in Flixweed (Descurainia sophia) Populations from China

Weed Science ◽  
2011 ◽  
Vol 59 (3) ◽  
pp. 376-379 ◽  
Author(s):  
Hai Lan Cui ◽  
Chao Xian Zhang ◽  
Shou Hui Wei ◽  
Hong Jun Zhang ◽  
Xiang Ju Li ◽  
...  
Keyword(s):  
Amino Acid ◽  
Molecular Basis ◽  
Resistance Mechanism ◽  
Point Mutations ◽  
Acetolactate Synthase ◽  
Amino Acid Position ◽  
Resistance Level ◽  
Coding Sequence ◽  
Whole Plant ◽  
Tribenuron Methyl

The molecular basis of resistance to tribenuron-methyl, an acetolactate synthase (ALS)–inhibiting herbicide was investigated in four resistant (R) and three susceptible (S) flixweed populations. The resistance level in the R populations was assessed in whole-plant pot experiments in a greenhouse, and resistance indices ranged from 723 to 1422. The ALS genes of the three S populations and four R populations were cloned and sequenced, and the full coding sequence of the ALS gene of flixweed was 2,004 bp. The sequences of the ALS genes of the three S populations collected from Shaanxi, Gansu, and Tianjin were identical. Comparison of the ALS gene sequences of the S and R populations withArabidopsisrevealed that proline at position 197 of the ALS gene was substituted by leucine in R population SSX-2, by alanine in R population SSX-3, and by serine in R populations TJ-2 and GS-2. In another study of two R flixweed populations from Hebei and Shaanxi, resistance was also related to mutation at position 197 of the ALS gene. Both studies confirmed tribenuron-methyl resistance in flixweed in China, with the resistance mechanism being conferred by specific ALS point mutations at amino acid position 197.

scholarly journals Genetic variability in cysteine protease genes ofHaemonchus contortus

Parasitology ◽  
2004 ◽  
Vol 128 (5) ◽  
pp. 549-559 ◽  
Author(s):  
A. RUIZ ◽  
J. M. MOLINA ◽  
A. NJUE ◽  
R. K. PRICHARD
Keyword(s):  
Amino Acid ◽  
Nucleotide Sequence ◽  
Genetic Variability ◽  
Amino Acid Sequence ◽  
Cysteine Protease ◽  
Haemonchus Contortus ◽  
Significant Variation ◽  
Nucleotide Diversity ◽  
Cysteine Proteases ◽  
Different Strains

To increase the existent genetic variability in cysteine proteases, a polymorphism study was performed inHaemonchus contortusby comparing 2 different strains of the parasite: North American (NA) and Spanish (SP) strains. For this purpose, the polymorphism of 5 previously reported genes (AC-1,AC-3,AC-4,AC-5andGCP-7) were analysed by PCR–SSCP and sequencing procedures. Based on the SSCP results, a total of 20 different alleles were identified for the 5lociassessed. Exceptlocus AC-5, all thelociwere polymorphic.Loci AC-1,AC-3,AC-4andGCP-7showed 5, 8, 2 and 4 alleles, respectively. The allelic frequencies ranged from 0·0070 to 0·8560 and were significantly different between strains. In addition, nucleotide diversity analyses showed a significant variation within and between strains. The variations in the nucleotide sequence of the different alleles were translated in some cases into changes in the amino acid sequence. Evidence of genetic variability in cysteine proteases from two different strains ofH. contortusfor the same set of genes had not been previously reported.

scholarly journals Molecular Identification of Family 38 α-Mannosidase of Bacillus sp. Strain GL1, Responsible for Complete Depolymerization of Xanthan

2002 ◽  
Vol 68 (6) ◽  
pp. 2731-2736 ◽  
Author(s):  
Hirokazu Nankai ◽  
Wataru Hashimoto ◽  
Kousaku Murata
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Cell Extract ◽  
Amino Acid Sequences ◽  
Glycoside Hydrolase Family ◽  
Sequence Information ◽  
Reading Frame ◽  
A Cell ◽  
Terminal Amino ◽  
Amino Acid Sequence Information

ABSTRACT When cells of Bacillus sp. strain GL1 were grown in a medium containing xanthan as a carbon source, α-mannosidase exhibiting activity toward p-nitrophenyl-α-d-mannopyranoside (pNP-α-d-Man) was produced intracellularly. The 350-kDa α-mannosidase purified from a cell extract of the bacterium was a trimer comprising three identical subunits, each with a molecular mass of 110 kDa. The enzyme hydrolyzed pNP-α-d-Man (Km = 0.49 mM) and d-mannosyl-(α-1,3)-d-glucose most efficiently at pH 7.5 to 9.0, indicating that the enzyme catalyzes the last step of the xanthan depolymerization pathway of Bacillus sp. strain GL1. The gene for α-mannosidase cloned most by using N-terminal amino acid sequence information contained an open reading frame (3,144 bp) capable of coding for a polypeptide with a molecular weight of 119,239. The deduced amino acid sequence showed homology with the amino acid sequences of α-mannosidases belonging to glycoside hydrolase family 38.

Target site–based penoxsulam resistance in barnyardgrass (Echinochloa crus-galli) from China

Weed Science ◽  
2019 ◽  
Vol 67 (3) ◽  
pp. 281-287 ◽  
Author(s):  
Jiapeng Fang ◽  
Tingting Liu ◽  
Yuhua Zhang ◽  
Jun Li ◽  
Liyao Dong
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Acetolactate Synthase ◽  
Target Site ◽  
Cross Resistance ◽  
Predicted Amino Acid Sequence ◽  
Sequence Analyses ◽  
Als Inhibitors ◽  
Higher Sensitivity

AbstractBarnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] is acknowledged to be the most troublesome weed in rice fields in Anhui and Jiangsu provinces of China. It cannot be effectively controlled using certain acetolactate synthase (ALS)-inhibiting herbicides, including penoxsulam. Echinochloa crus-galli samples with suspected resistance to penoxsulam were collected to identify the target site–based mechanism underlying this resistance. Populations AXXZ-2 and JNRG-2 showed 33- and 7.3-fold resistance to penoxsulam, respectively, compared with the susceptible JLGY-3 population. Cross-resistance to other ALS inhibitors was reported in AXXZ-2 but not in JNRG-2, and occasionally showed higher sensitivity than JLGY-3. In vitro ALS activity assays revealed that penoxsulam concentrations required to inhibit 50% of ALS activity were 11 and 5.2 times greater in AXXZ-2 and JNRG-2, respectively, than in JLGY-3. DNA and predicted amino acid sequence analyses of ALS revealed Ala-205-Val and Ala-122-Gly substitutions in AXXZ-2 and JNRG-2, respectively. Our results indicate that these substitutions in ALS are at least partially responsible for resistance to penoxsulam.

scholarly journals Enzymatic Properties and Ryegrass Resistance Mechanism to Iodosulfuron-Methyl-Sodium Herbicide

2019 ◽  
Vol 37 ◽  
Author(s):  
F. MARIANI ◽  
S.A. SENSEMAM ◽  
L. VARGAS ◽  
D. AGOSTINETO ◽  
L.A. ÁVILA ◽  
...  
Keyword(s):  
Amino Acids ◽  
Enzyme Activity ◽  
Herbicide Resistance ◽  
Lolium Multiflorum ◽  
Resistance Mechanism ◽  
Acetolactate Synthase ◽  
Enzymatic Properties ◽  
Michaelis Constant ◽  
In Vitro Characterization

ABSTRACT: Ryegrass(Lolium multiflorum)is one of the most worrisome species with regard to herbicide resistance. This study aimed at characterizing the acetolactate synthase (ALS) enzyme activity of resistant biotypes (NC and AR) and susceptible biotypes to iodosulfuron-methyl-sodium (iodosulfuron). Different concentrations of pyruvate (1, 10, 20, 40, 60, 80 and 100 mM), of iodosulfuron (0 to 100 µM for the resistant biotypes and 0 to 0.5 µM for the susceptible biotype) and concentrations of valine, leucine and isoleucine (0, 0.001, 0.01, 0.1, 1, 10 and 100 mM) were used for the in vitro characterization. According to the results, the Michaelis constant (Km) values (pyruvate) for the assessed biotypes were similar. With iodosulfuron, resistant biotypes needed 395 to 779 times more herbicide in order to inhibit 50% of the enzyme activity, compared to the susceptible biotype. This confirmed a sensitivity modification of the ALS enzyme in the resistant biotypes. The resistant biotypes were less sensitive to the inhibition of the enzyme activity in the presence of the three amino acids. It was possible to conclude that biotype resistance was due to the enzyme insensitivity to iodosulfuron.

Molecular Characterization of Genes Coding for Wild-Type and Sulfonylurea-Resistant Acetolactate Synthase in the Cyanobacterium Synechococcus PC C7942

1990 ◽  
Vol 45 (5) ◽  
pp. 538-543 ◽  
Author(s):  
D. Friedberg ◽  
J. Seijffers
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Molecular Characterization ◽  
Amino Acid Level ◽  
Acetolactate Synthase ◽  
Mutant Gene ◽  
Wild Type ◽  
E Coli

We present here the isolation and molecular characterization of acetolactate synthase (ALS) genes from the cyanobacterium Synechococcus PCC7942 which specify a sulfonylurea-sensitive enzyme and from the sulfonylurea-resistant mutant SM3/20, which specify resistance to sulfonylurea herbicides. The ALS gene was cloned and mapped by complementation of an Escherichia coli ilv auxotroph that requires branched-chain amino acids for growth and lacks ALS activity. The cyanobacterial gene is efficiently expressed in this heterologous host. The ALS gene codes for 612 amino acids and shows high sequence homology (46%) at the amino acid level with ALS III of E. coli and with the tobacco ALS. The resistant phenotype is a consequence of proline to serine substitution in residue 115 of the deduced amino acid sequence. Functional expression of the mutant gene in wild-type Synechococcus and in E. coli confirmed that this amino-acid substitution is responsible for the resistance. Yet the deduced amino-acid sequence as compared with othjer ALS proteins supports the notion that the amino-acid context of the substitution is important for the resistance.

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