The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Xu Wang - One of the best experts on this subject based on the ideXlab platform.
-
Target-site basis for resistance to imazethapyr in redroot amaranth (Amaranthus retroflexus L.).
Pesticide biochemistry and physiology, 2015Co-Authors: Zhaofeng Huang, Hongjuan Huang, Jinyi Chen, Jingchao Chen, Shouhui Wei, Chaoxian Zhang, Xinxin Zhou, Xu WangAbstract:Experiments were conducted to confirm imazethapyr resistance in redroot amaranth (Amaranthus retroflexus L.) and study the target-site based mechanism for the resistance. Whole-plant response experiments revealed that the resistant (R) population exhibited 19.16 fold resistance to imazethapyr compared with the susceptible (S) population. In vitro ALS activity assay demonstrated that the imazethapyr I50 value of the R population was 21.33 times greater than that of the S population. However, qRT-PCR analysis revealed that there is no difference in ALS gene expression between the R and S populations. Sequence analysis revealed an Asp-376-Glu substitution in ALS in the R population. In order to verify that the imazethapyr resistance was conferred by Asp-376-Glu mutation, the ALS-R and ALS-S genes were fused to the CaMV 35S promoter and introduced into Arabidopsis respectively. The expression of ALS-R in transgenic Arabidopsis plants exhibited 13.79 fold resistance to imazethapyr compared to ALS-S transgenic Arabidopsis.
-
Molecular basis of resistance to imazethapyr in redroot pigweed (Amaranthus retroflexus L.) populations from China.
Pesticide biochemistry and physiology, 2015Co-Authors: Jinyi Chen, Zhaofeng Huang, Hongjuan Huang, Jingchao Chen, Shouhui Wei, Chaoxian Zhang, Xu WangAbstract:Three putative resistant Amaranthus retroflexus L. populations were collected in Heilongjiang province in China. Whole plant bioassays indicated high resistance (RI > 10) to imazethapyr in the three populations. In vitro acetolactate synthase (ALS) assays revealed that ALS from populations H3, H17 and H39 was less sensitive to imazethapyr inhibition compared to the susceptible population H76. The half-maximal inhibitory concentration (I50) values for H3, H17 and H39 were 14.83, 15.27 and 268 times greater, respectively, than that of the susceptible population H76. Three nucleotide mutations resulted in three known resistance-endowing amino acid substitutions, Ala-205-Val, Trp-574-Leu and Ser-653-Thr in the three resistant populations respectively. Therefore, ALS target-site mutations in resistant A. retroflexus could be responsible for imazethapyr resistance.
Ivana Plačková - One of the best experts on this subject based on the ideXlab platform.
-
Location of Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa populations.
2012Co-Authors: Bohumil Mandák, Petr Zákravský, Václav Mahelka, Ivana PlačkováAbstract:Map showing the location of the 20 populations of each of the three species under study, i.e. Amaranthus retroflexus (empty circles), Carduus acanthoides (empty squares) and Pastinaca sativa (empty triangles). Four localities of each species were selected and used in the present study (highlighted by full symbols).
-
Analysis of molecular variance in Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa.
2012Co-Authors: Bohumil Mandák, Petr Zákravský, Václav Mahelka, Ivana PlačkováAbstract:Analysis of molecular variance among populations, among life history stages within populations, and within life history stages of Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa. Significance of variance components were tested by a permutation test (*P
-
Genetic diversity of Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa (from other studies).
2012Co-Authors: Bohumil Mandák, Petr Zákravský, Václav Mahelka, Ivana PlačkováAbstract:Comparison of genetic diversity within 20 populations of Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa based on allozyme loci (data taken from [45], [46] and Mandák et al., unpublished data, respectively). PL = percentage of polymorphic loci. A = average number of alleles per polymorphic locus. Ho = observed heterozygosity. He = expected heterozygosity. F, f, θ = Weir and Cockerham’s estimates of Wright’s F statistics (FIT, FIS and FST, respectively) which represents deviations from Hardy-Weinberg expectations over all populations, deviations within individual populations and the proportion of total genetic diversity partitioned among populations. * Significant deviation (P
-
Population genetic characteristics for individual life history stages of Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa.
2012Co-Authors: Bohumil Mandák, Petr Zákravský, Václav Mahelka, Ivana PlačkováAbstract:Statistical comparison of allelic richness (RS), observed heterozygosity (HO), gene diversity (HS), inbreeding coefficient (FIS) and levels of differentiation among populations (FST) for individual life history stages of Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa. WSB – winter seed bank, SSB – summer seed bank. Probability values for differences between life history stages are for two-sided t-tests after 10 000 permutations. * Significant deviation (P
-
Population genetic structure of the noxious weed Amaranthus retroflexus in Central Europe
Flora - Morphology Distribution Functional Ecology of Plants, 2011Co-Authors: Bohumil Mandák, Petr Zákravský, Petr Dostál, Ivana PlačkováAbstract:Abstract Genetic variation was assessed in a range of populations of Amaranthus retroflexus using isoenzyme analysis. Population genetic diversity was measured by evaluating patterns of variation at six putatively neutral isoenzyme loci (comprising 24 putative alleles) within and among 20 populations of A. retroflexus collected in different habitats: ruderal habitats, cereal fields and hop gardens. Amaranthus retroflexus is a noxious weed of North American origin that infests various crops. Overall, A. retroflexus displayed moderate levels of genetic diversity in comparison with other herbaceous plants. The percentage of polymorphic loci was 50.0%, with mean values of 2.01, 0.142 and 0.227 for the average number of alleles per polymorphic locus (A), observed heterozygosity (Ho) and expected heterozygosity (He), respectively. A discrepancy between observed and expected heterozygosity and significant differences from H-W expectation indicate that there is an excess of homozygotes in many populations. As a result, there is strong evidence of inbreeding within populations (FIS = 0.382) and significant population differentiation (FST = 0.270). Even though the species is partly autogamous, inbreeding does not lead to strong inbreeding depression resulting from self-pollination, as inbreeding has no effect on the success of the species in today's countryside. Moreover, allele frequencies detected in agricultural habitats (i.e., cereal fields and hop gardens) differed from those detected in populations collected from ruderal habitats, which is probably caused by systematic application of herbicides in agricultural ecosystems.
Zhaofeng Huang - One of the best experts on this subject based on the ideXlab platform.
-
Investigation of resistance mechanism to fomesafen in Amaranthus retroflexus L.
Pesticide biochemistry and physiology, 2020Co-Authors: Zhaofeng Huang, Hongjuan Huang, Chaoxian Zhang, Hailan Cui, Chunyu Wang, Shouhui WeiAbstract:Amaranthus retroflexus L. is one of the most troublesome weeds in autumn-crop fields in Northeast China. In recent years, field applications of fomesafen have failed to control an A. retroflexus population in Heilongjiang Province, China. Therefore, in this study, experiments were conducted to determine the resistance of A. retroflexus to fomesafen and investigate the molecular basis of herbicide resistance. Whole-plant dose-response experiments showed that the resistant (R) population exhibited 41.8-fold resistance to fomesafen compared with the susceptible (S) population. Target-gene sequence analysis revealed an Arg-128-Gly substitution in the protoporphyrinogen oxidase (PPO) in the R population. The response of PPO2 transgenic Arabidopsis thaliana to fomesafen demonstrated that the Arg-128-Gly substitution conferred high resistance to fomesafen. Cross- and multiple-resistance analyses indicated that the R population was cross-resistant to lactofen and carfentrazone-ethyl but was sensitive to imazethapyr, thifensulfuron-methyl, atrazine, and glyphosate. This study indicated that the Arg-128-Gly substitution is the main reason for A. retroflexus resistance to fomesafen. To our knowledge, this is the first report of a target-site based mechanism for the resistance to a PPO-inhibiting herbicide in A. retroflexus.
-
Nicosulfuron-resistant Amaranthus retroflexus L. in Northeast China
Crop Protection, 2019Co-Authors: Zhaofeng Huang, Hongjuan Huang, Jinyi Chen, Jingchao Chen, Shouhui Wei, Chaoxian ZhangAbstract:Abstract Amaranthus retroflexus L. is a troublesome broadleaf weed in autumn crop fields in China. Farmers complain that A. retroflexus cannot be controlled by nicosulfuron at the recommended field rate in maize fields in Heilongjiang Province. The aim of this study was to determine the molecular basis of nicosulfuron resistance in A. retroflexus. Whole-plant response assays revealed that two resistant populations (R1 and R2) exhibited resistance (14.50- and 44.24-fold) to nicosulfuron. In vitro acetolactate synthase (ALS) activity assays indicated that the nicosulfuron I50 values for R1 and R2 populations were 8.12 and 22.32 times higher than that for the susceptible population (S), respectively. Sequence analysis of ALS showed amino acid mutations Ser-653-Asn in R1 and Trp-574-Leu in R2. These two target-site mutations seem to play a primary role in A. retroflexus resistance to nicosulfuron, and this is the first time that the Ser-653-Asn mutation has been reported in this species.
-
Target-site basis for resistance to imazethapyr in redroot amaranth (Amaranthus retroflexus L.).
Pesticide biochemistry and physiology, 2015Co-Authors: Zhaofeng Huang, Hongjuan Huang, Jinyi Chen, Jingchao Chen, Shouhui Wei, Chaoxian Zhang, Xinxin Zhou, Xu WangAbstract:Experiments were conducted to confirm imazethapyr resistance in redroot amaranth (Amaranthus retroflexus L.) and study the target-site based mechanism for the resistance. Whole-plant response experiments revealed that the resistant (R) population exhibited 19.16 fold resistance to imazethapyr compared with the susceptible (S) population. In vitro ALS activity assay demonstrated that the imazethapyr I50 value of the R population was 21.33 times greater than that of the S population. However, qRT-PCR analysis revealed that there is no difference in ALS gene expression between the R and S populations. Sequence analysis revealed an Asp-376-Glu substitution in ALS in the R population. In order to verify that the imazethapyr resistance was conferred by Asp-376-Glu mutation, the ALS-R and ALS-S genes were fused to the CaMV 35S promoter and introduced into Arabidopsis respectively. The expression of ALS-R in transgenic Arabidopsis plants exhibited 13.79 fold resistance to imazethapyr compared to ALS-S transgenic Arabidopsis.
-
Molecular basis of resistance to imazethapyr in redroot pigweed (Amaranthus retroflexus L.) populations from China.
Pesticide biochemistry and physiology, 2015Co-Authors: Jinyi Chen, Zhaofeng Huang, Hongjuan Huang, Jingchao Chen, Shouhui Wei, Chaoxian Zhang, Xu WangAbstract:Three putative resistant Amaranthus retroflexus L. populations were collected in Heilongjiang province in China. Whole plant bioassays indicated high resistance (RI > 10) to imazethapyr in the three populations. In vitro acetolactate synthase (ALS) assays revealed that ALS from populations H3, H17 and H39 was less sensitive to imazethapyr inhibition compared to the susceptible population H76. The half-maximal inhibitory concentration (I50) values for H3, H17 and H39 were 14.83, 15.27 and 268 times greater, respectively, than that of the susceptible population H76. Three nucleotide mutations resulted in three known resistance-endowing amino acid substitutions, Ala-205-Val, Trp-574-Leu and Ser-653-Thr in the three resistant populations respectively. Therefore, ALS target-site mutations in resistant A. retroflexus could be responsible for imazethapyr resistance.
Shouhui Wei - One of the best experts on this subject based on the ideXlab platform.
-
Investigation of resistance mechanism to fomesafen in Amaranthus retroflexus L.
Pesticide biochemistry and physiology, 2020Co-Authors: Zhaofeng Huang, Hongjuan Huang, Chaoxian Zhang, Hailan Cui, Chunyu Wang, Shouhui WeiAbstract:Amaranthus retroflexus L. is one of the most troublesome weeds in autumn-crop fields in Northeast China. In recent years, field applications of fomesafen have failed to control an A. retroflexus population in Heilongjiang Province, China. Therefore, in this study, experiments were conducted to determine the resistance of A. retroflexus to fomesafen and investigate the molecular basis of herbicide resistance. Whole-plant dose-response experiments showed that the resistant (R) population exhibited 41.8-fold resistance to fomesafen compared with the susceptible (S) population. Target-gene sequence analysis revealed an Arg-128-Gly substitution in the protoporphyrinogen oxidase (PPO) in the R population. The response of PPO2 transgenic Arabidopsis thaliana to fomesafen demonstrated that the Arg-128-Gly substitution conferred high resistance to fomesafen. Cross- and multiple-resistance analyses indicated that the R population was cross-resistant to lactofen and carfentrazone-ethyl but was sensitive to imazethapyr, thifensulfuron-methyl, atrazine, and glyphosate. This study indicated that the Arg-128-Gly substitution is the main reason for A. retroflexus resistance to fomesafen. To our knowledge, this is the first report of a target-site based mechanism for the resistance to a PPO-inhibiting herbicide in A. retroflexus.
-
Nicosulfuron-resistant Amaranthus retroflexus L. in Northeast China
Crop Protection, 2019Co-Authors: Zhaofeng Huang, Hongjuan Huang, Jinyi Chen, Jingchao Chen, Shouhui Wei, Chaoxian ZhangAbstract:Abstract Amaranthus retroflexus L. is a troublesome broadleaf weed in autumn crop fields in China. Farmers complain that A. retroflexus cannot be controlled by nicosulfuron at the recommended field rate in maize fields in Heilongjiang Province. The aim of this study was to determine the molecular basis of nicosulfuron resistance in A. retroflexus. Whole-plant response assays revealed that two resistant populations (R1 and R2) exhibited resistance (14.50- and 44.24-fold) to nicosulfuron. In vitro acetolactate synthase (ALS) activity assays indicated that the nicosulfuron I50 values for R1 and R2 populations were 8.12 and 22.32 times higher than that for the susceptible population (S), respectively. Sequence analysis of ALS showed amino acid mutations Ser-653-Asn in R1 and Trp-574-Leu in R2. These two target-site mutations seem to play a primary role in A. retroflexus resistance to nicosulfuron, and this is the first time that the Ser-653-Asn mutation has been reported in this species.
-
Target-site basis for resistance to imazethapyr in redroot amaranth (Amaranthus retroflexus L.).
Pesticide biochemistry and physiology, 2015Co-Authors: Zhaofeng Huang, Hongjuan Huang, Jinyi Chen, Jingchao Chen, Shouhui Wei, Chaoxian Zhang, Xinxin Zhou, Xu WangAbstract:Experiments were conducted to confirm imazethapyr resistance in redroot amaranth (Amaranthus retroflexus L.) and study the target-site based mechanism for the resistance. Whole-plant response experiments revealed that the resistant (R) population exhibited 19.16 fold resistance to imazethapyr compared with the susceptible (S) population. In vitro ALS activity assay demonstrated that the imazethapyr I50 value of the R population was 21.33 times greater than that of the S population. However, qRT-PCR analysis revealed that there is no difference in ALS gene expression between the R and S populations. Sequence analysis revealed an Asp-376-Glu substitution in ALS in the R population. In order to verify that the imazethapyr resistance was conferred by Asp-376-Glu mutation, the ALS-R and ALS-S genes were fused to the CaMV 35S promoter and introduced into Arabidopsis respectively. The expression of ALS-R in transgenic Arabidopsis plants exhibited 13.79 fold resistance to imazethapyr compared to ALS-S transgenic Arabidopsis.
-
Molecular basis of resistance to imazethapyr in redroot pigweed (Amaranthus retroflexus L.) populations from China.
Pesticide biochemistry and physiology, 2015Co-Authors: Jinyi Chen, Zhaofeng Huang, Hongjuan Huang, Jingchao Chen, Shouhui Wei, Chaoxian Zhang, Xu WangAbstract:Three putative resistant Amaranthus retroflexus L. populations were collected in Heilongjiang province in China. Whole plant bioassays indicated high resistance (RI > 10) to imazethapyr in the three populations. In vitro acetolactate synthase (ALS) assays revealed that ALS from populations H3, H17 and H39 was less sensitive to imazethapyr inhibition compared to the susceptible population H76. The half-maximal inhibitory concentration (I50) values for H3, H17 and H39 were 14.83, 15.27 and 268 times greater, respectively, than that of the susceptible population H76. Three nucleotide mutations resulted in three known resistance-endowing amino acid substitutions, Ala-205-Val, Trp-574-Leu and Ser-653-Thr in the three resistant populations respectively. Therefore, ALS target-site mutations in resistant A. retroflexus could be responsible for imazethapyr resistance.
Bohumil Mandák - One of the best experts on this subject based on the ideXlab platform.
-
Location of Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa populations.
2012Co-Authors: Bohumil Mandák, Petr Zákravský, Václav Mahelka, Ivana PlačkováAbstract:Map showing the location of the 20 populations of each of the three species under study, i.e. Amaranthus retroflexus (empty circles), Carduus acanthoides (empty squares) and Pastinaca sativa (empty triangles). Four localities of each species were selected and used in the present study (highlighted by full symbols).
-
Analysis of molecular variance in Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa.
2012Co-Authors: Bohumil Mandák, Petr Zákravský, Václav Mahelka, Ivana PlačkováAbstract:Analysis of molecular variance among populations, among life history stages within populations, and within life history stages of Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa. Significance of variance components were tested by a permutation test (*P
-
Genetic diversity of Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa (from other studies).
2012Co-Authors: Bohumil Mandák, Petr Zákravský, Václav Mahelka, Ivana PlačkováAbstract:Comparison of genetic diversity within 20 populations of Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa based on allozyme loci (data taken from [45], [46] and Mandák et al., unpublished data, respectively). PL = percentage of polymorphic loci. A = average number of alleles per polymorphic locus. Ho = observed heterozygosity. He = expected heterozygosity. F, f, θ = Weir and Cockerham’s estimates of Wright’s F statistics (FIT, FIS and FST, respectively) which represents deviations from Hardy-Weinberg expectations over all populations, deviations within individual populations and the proportion of total genetic diversity partitioned among populations. * Significant deviation (P
-
Population genetic characteristics for individual life history stages of Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa.
2012Co-Authors: Bohumil Mandák, Petr Zákravský, Václav Mahelka, Ivana PlačkováAbstract:Statistical comparison of allelic richness (RS), observed heterozygosity (HO), gene diversity (HS), inbreeding coefficient (FIS) and levels of differentiation among populations (FST) for individual life history stages of Amaranthus retroflexus, Carduus acanthoides and Pastinaca sativa. WSB – winter seed bank, SSB – summer seed bank. Probability values for differences between life history stages are for two-sided t-tests after 10 000 permutations. * Significant deviation (P
-
Population genetic structure of the noxious weed Amaranthus retroflexus in
2011Co-Authors: Bohumil Mandák, Petr Zákravsk, Petr Dostál, Ivana PlaAbstract:Genetic variation was assessed in a range of populations of Amaranthus retroflexus using isoenzyme analysis. Population genetic diversity was measured by evaluating patterns of variation at six putatively neutral isoenzyme loci (comprising 24 putative alleles) within and among 20 populations of A. retroflexus collected in different habitats: ruderal habitats, cereal fields and hop gardens. Amaranthus retroflexus is a noxious weed of North American origin that infests various crops. Overall, A. retroflexus displayed moderate levels of genetic diversity in comparison with other herbaceous plants. The percentage of polymorphic loci was 50.0%, with mean values of 2.01, 0.142 and 0.227 for the average number of alleles per polymorphic locus (A), observed heterozygosity (Ho) and expected heterozygosity (He), respectively. A discrepancy between observed and expected heterozygosity and significant differences from H-W expectation indicate that there is an excess of homozygotes in many populations. As a result, there is strong evidence of inbreeding within populations (FIS = 0.382) and significant population differentiation (FST = 0.270). Even though the species is partly autogamous, inbreeding does not lead to strong inbreeding depression resulting from self-pollination, as inbreeding has no effect on the success of the species in today’s countryside. Moreover, allele frequencies detected in agricultural habitats (i.e., cereal fields and hop gardens) differed from those detected in populations collected from ruderal habitats, which is probably caused by systematic application of herbicides in agricultural ecosystems.