宁夏稻田稗草对氰氟草酯抗药性及多抗性与交互抗性研究

为明确宁夏地区稻田稗草对乙酰辅酶A羧化酶抑制剂类除草剂氰氟草酯的抗药性水平以及对其他除草剂可能存在的交互抗性与多抗性情况,采用整株生物测定法研究了采自宁夏稻田的36个稗草种群对氰氟草酯的抗药性, 并使用单剂量法测定了各种群对五氟磺草胺、嘧啶肟草醚、噁唑酰草胺、二氯喹啉酸和敌稗的交互抗性及多抗性。结果表明, 以氰氟草酯GR50数值最小的生物型为敏感生物型计算抗性指数(RI), 仅有1个稗草种群在推荐剂量下被完全杀死, RI≤ 3.0; 11个稗草种群的RI范围为3.3～9.4, 表现出低水平抗性, 发生频率为30.56%; 19个种群的RI范围为10.3~58.3, 表现出中等水平抗性; 发生频率为52.78%; 5个稗草种群的RI＞100, 表现出高水平抗性, 占比13.89%, 其中采自银川市贺兰县立岗镇通义村的稗草种群抗性水平最高。交互抗性和多抗性研究结果表明, 在田间最高推荐剂量下氰氟草酯对稗草鲜重抑制率低于90%的种群中, 58%的稗草种群对噁唑酰草胺产生了交互抗性, 对五氟磺草胺、嘧啶肟草醚、二氯喹啉酸和敌稗产生多抗性的种群所占百分率分别为94%、100%、100%和18%。研究发现宁夏地区水稻田多数稗草种群对氰氟草酯产生了不同程度的抗药性, 并对其他常用稻田除草剂产生了交互抗性与多抗性, 其中银北地区稗草种群抗药性水平最高, 部分地区稗草抗性已达到高抗水平, 宁夏水稻田亟须抗性稗草综合治理技术的研究。     

Amaranthus hybridus populations resistant to triazine and acetolactate synthase-inhibiting herbicides

Amaranthus hybridus L. populations (A, B and C) obtained from escapes in Massac County and Pope County fields in southern Illinois, USA were subjected to greenhouse and laboratory experiments to measure multiple resistance to triazine and acetolactate synthase (ALS)‐inhibiting herbicides and cross‐resistance between sulfonylurea and imidazolinone herbicides. Phytotoxicity responses of the three populations revealed that only population B exhibited multiple resistances to triazine and ALS‐inhibiting herbicides. This population was >167‐, >152‐ and >189‐fold resistant to atrazine, imazamox and thifensulfuron, respectively, at the whole plant level compared with the susceptible population. Population A was only resistant to triazines and population C was only resistant to ALS‐inhibiting herbicides. Results from in vivo ALS enzyme and chlorophyll fluorescence assays confirmed these findings and indicated that an altered site‐of‐action mediated resistance to both triazine and ALS‐inhibiting herbicides. Gene sequencing revealed that a glycine for serine substitution at residue 264 of the D1 protein, and a leucine for tryptophan substitution at residue 574 of ALS were the causes of resistance for the three populations.     

Monitoring the temporal changes in herbicide-resistant Amaranthus tuberculatus: a landscape-scale probability-based estimation in Iowa

Background

A landscape-scale probability-based sampling of Iowa soybean [Glycine max (L.) Merr.] fields was conducted in 2013 and 2019; Amaranthus tuberculatus [Moq.] J.D. Sauer seed was collected from 97 random geospatial selected fields. The objectives were to evaluate the prevalence and distribution of herbicide-resistant A. tuberculatus (waterhemp) in soybean fields and evaluate temporal changes over 6 years. Amaranthus tuberculatus seedlings were evaluated for resistance to imazethapyr, atrazine, glyphosate, lactofen and mesotrione at 1× and 4× label rates.

Results

Resistance to imazethapyr, glyphosate, lactofen and mesotrione at the 1× rate increased significantly from 2013 to 2019 and was found in 99%, 97%, 16% and 15% of Iowa A. tuberculatus populations in 2019, respectively. Resistance to atrazine at the 4× rate increased over time; atrazine resistance was found in 68% of populations in 2019. Three-way multiple herbicide-resistant A. tuberculatus was the most frequent and increased significantly to 4× rates from 16% in 2013 to 43% of populations in 2019. All A. tuberculatus populations resistant to HPPD-inhibitor herbicides also were resistant to atrazine.

Conclusion

To the best of our knowledge, this is the first probability-based study that presented evolution of A. tuberculatus herbicide resistance over time. The results demonstrated that imazethapyr, atrazine and glyphosate resistance in Iowa A. tuberculatus populations was frequent whereas resistance to lactofen and mesotrione was less frequent. Most Iowa A. tuberculatus populations evolved resistance to multiple sites of action over time. The results of our study are widely applicable given the similarities in weed management practices throughout the Midwest United States. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

The benefits of herbicide-resistant crops

Since 1996, genetically modified herbicide-resistant crops, primarily glyphosate-resistant soybean, corn, cotton and canola, have helped to revolutionize weed management and have become an important tool in crop production practices. Glyphosate-resistant crops have enabled the implementation of weed management practices that have improved yield and profitability while better protecting the environment. Growers have recognized their benefits and have made glyphosate-resistant crops the most rapidly adopted technology in the history of agriculture. Weed management systems with glyphosate-resistant crops have often relied on glyphosate alone, have been easy to use and have been effective, economical and more environmentally friendly than the systems they have replaced. Glyphosate has worked extremely well in controlling weeds in glyphosate-resistant crops for more than a decade, but some key weeds have evolved resistance, and using glyphosate alone has proved unsustainable. Now, growers need to renew their weed management practices and use glyphosate with other cultural, mechanical and herbicide options in integrated systems. New multiple-herbicide-resistant crops with resistance to glyphosate and other herbicides will expand the utility of existing herbicide technologies and will be an important component of future weed management systems that help to sustain the current benefits of high-efficiency and high-production agriculture. Copyright © 2012 Society of Chemical Industry     

Efficacy of cultural control methods for combating herbicide-resistant Lolium rigidum

Herbicide-resistant populations of annual ryegrass (Lolium rigidum) are estimated to affect crop production on about 5000 farms in southern Australia. In order to manage resistant populations, some farmers have adopted a two-to-three-year pasture phase which allows use of grazing by sheep, and non-selective herbicides to deplete the weed seed-bank. However, in low-to-medium rainfall zones, where financial returns from pastures are relatively low, farmers have generally combined cultural practices for weed management with the use of alternative herbicides, mainly trifluralin. Used singly, none of the currently available cultural techniques provides an adequate level of weed control. However, when used in carefully planned combinations, extremely effective ryegrass control can be achieved. Some of the important cultural practices for ryegrass control include delayed sowing (sometimes in conjunction with a shallow autumn cultivation); stubble burning; cutting the crop for hay or green manure, increased crop density and capture of weed seeds at harvest. Selection of crop species and cultivars with superior weed suppression potential is also receiving considerable attention. ©1997 SCI     

抗药性杂草与治理

抗药性杂草对农田杂草治理和农业生产构成严重威胁,成为备受全球关注的严重问题。随着长期、大量使用相对有限的化学除草剂,全球抗药性杂草发展迅猛,目前已有217种杂草对化学除草剂产生了抗药性,我国抗药性杂草发展也十分迅猛。本文在介绍杂草抗药性基本概念、抗药性杂草发展过程、抗药性杂草现状的基础上,重点描述了抗药性杂草治理策略,以期为我国抗药性杂草研究和治理提供参考。     

The ecological fitness of ALS-resistant Amaranthus retroflexus and multiple-resistant Amaranthus blitoides

Summary Field studies were conducted to evaluate the ecological fitness of Amaranthus spp. biotypes that evolved resistance to either acetolactate synthase (ALS) inhibitors ( A. retroflexus , SuR), to triazine herbicides ( A. blitoides , SuS/TR), or to both ( A. blitoides , SuR/TR), and estimate their ecological fitness under competitive conditions. The plants were grown in monoculture and in replacement series experiments. The examined mixtures were 100%S, 75%S/25%R, 50%S/50%R, 25%S/75%R and 100%R, at a constant stand of 400 plants m⁻². The SuR and SuS A. retroflexus biotypes attained similar shoot dry biomass per plant, biomass per plot and relative yield total (RYT) = 1. In monoculture, the final shoot biomass of A. blitoides biotypes SuS/TS plants was higher than that of SuR/TR and SuS/TR. A negative effect of association was observed, amensalism, when SuS/TS was grown in mixture with SuR/TR, in favour of the wild type. However, SuR/TR and SuS/TR biomass was not influenced by the presence of the competitor. These data support the hypothesis that the ALS-resistance trait in A. retroflexus and A. blitoides is not associated with growth penalty and did not incur ecological cost in the field. We suggest that the cause of the observed reduction in growth rendering the SuS/TR and SuR/TR less fit than the wild type is due to the triazine resistance, and may facilitate their dissipation.     

Influence of herbicide-resistant canola on the environmental impact of weed management

The growth of herbicide-resistant canola varieties increased from 10% of the canola area in Canada in 1996, when the technology was first introduced, to 80% in 2000. From 1995 to 2000, the amount of herbicide active ingredient applied per hectare of canola declined by 42.8% and the Environmental Impact (EI) per hectare, calculated using the Environmental Impact Quotient for individual herbicides and the amounts of active ingredients applied, declined 36.8%. The amount of herbicide active ingredient per hectare applied to conventional canola was consistently higher than that applied to herbicide-resistant canola each year between 1996 and 2000. Similarly, the EI of herbicide use per hectare in conventional canola was higher than that of herbicide-resistant canola during the same time period. Since 1996, herbicide use has shifted from broadcast applications of soil-active herbicides to post-emergence applications of herbicides with broad-spectrum foliar activity. The decline in herbicide use and EI since the introduction of herbicide-resistant varieties was due to increased use of chemicals with lower application rates, a reduced number of applications and a decreased need for herbicide combinations.     

Population structure of ALS-inhibiting herbicide-resistant Sonchus oleraceus in South Australia

Background

Annual sowthistle is a weed that is difficult to control in lentil crops in southern Australia due to a lack of herbicide options, widespread herbicide resistance and prolific production of highly mobile seed. This study investigates herbicide resistance in annual sowthistle in the Mid-North (MN) and Yorke Peninsula (YP) regions of South Australia, identifies and characterizes the mechanisms of acetolactate-synthase (ALS)-inhibitor resistance in this amphidiploid species, and combines this with analyses of population structure and gene flow.

Results

ALS-inhibitor-resistant annual sowthistle is widespread across the YP and MN of South Australia and is associated with a variety of Proline-197 mutations of the ALS gene, including leucine, alanine, arginine, serine, threonine and histidine. These mutations were found in different combinations on either of the two copies of the ALS gene. An additional 200 tissue samples were collected from across a single field on the YP and the ALS gene was sequenced for all these individuals. Different ALS-inhibitor resistance profiles were evident between mutation combinations and within mutation combinations, possibly mediated by differing subgenome assortment of the mutations, or altered gene experession of the two ALS homeologs. Population genetics analysis showed evidence of long-distance dispersal, resulting in highly mobile resistance genes, and multiple instances of resistance mutation evolution.

Conclusions

Continuing selection of Sonchus oleraceus populations with ALS-inhibiting herbicides has resulted in the accumulation of additional mutations within the ALS gene. New practices to control herbicide-resistant S. oleraceus should be examined, and control should focus on reducing seed set and dispersal to prevent the spread of emerging cases of resistance. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Sulfometuron-resistant Amaranthus retroflexus: cross-resistance and molecular basis for resistance to acetolactate synthase-inhibiting herbicides

A biotype of Amaranthus retroflexus L. is the first weed in Israel to develop resistance to acetolactate synthase (ALS)-inhibiting herbicides. The resistant biotype (Su-R) was collected from Ganot, a site that had been treated for more than 3 consecutive years with sulfometuron-methyl + simazine. On the whole-plant basis, the resistance ratio ( ED₅₀ Su-R)/( ED₅₀ Su-S) was 6–127 for sulfonylureas, 4–63 for imidazolinones, 20–35 for triazolopyrimidines and 11 for pyrithiobac-sodium. Similar levels of resistance were found also when the herbicides were applied before emergence. Based on a root elongation bioassay, Su-R was 3240-fold more resistant to sulfometuron-methyl than Su-S. In vitro studies have shown that the Su-R biotype was resistant at the enzyme level to all ALS inhibitors tested. The nucleotide sequences of two amplified regions between the Su-S and the Su-R differed in only one nucleotide. One substitution has occurred in domain A, cytosine by thymine (C C C to C T C) at position 248, that confers an exchange of the amino acid proline in the susceptible to leucine in the Su-R. The proline to leucine change in domain A is the only difference in the amino acid primary structure of the regions sequenced, indicating that it is responsible for the ALS-inhibitor resistance observed.     

Glutathione transferases in herbicide-resistant and herbicide-susceptible black-grass (Alopecurus myosuroides)

Glutathione transferase (GST) activities toward the selective herbicide fenoxaprop-ethyl, together with thiol contents, have been compared in seedlings of wheat (Triticum aestivum) and two populations of black-grass (Alopecurus myosuroides) which are resistant to a range of herbicides (Peldon and Lincs E1), and a black-grass population which is susceptible to herbicides (Rothamsted). GST activities toward the non-cereal herbicides metolachlor and fluorodifen were also determined. On the basis of enzyme specific activity, GST activities toward fenoxaprop-ethyl in the leaves were in the order wheat>Peldon=Lincs E1>Rothamsted, while with fluorodifen and metolachlor the order was Peldon=Lincs E1>Rothamsted>wheat. Using an antibody raised to the major GST from wheat, which is composed of 25-kDa subunits, it was shown that the enhanced GST activities in both Peldon and Lincs E1 correlated with an increased expression of a 25-kDa polypeptide and the appearance of novel 27-kDa and 28-kDa polypeptides. Leaves of both wheat and black-grass contained glutathione and hydroxymethylglutathione, with the concentrations of glutathione being in the order Peldon>Lincs E1=Rothamsted=wheat. However, in glasshouse dose-response assays, the Lincs E1 population showed much greater resistance to fenoxaprop-ethyl than Peldon. We conclude that high GST activities and the availability of glutathione may contribute partially to the relative tolerance of black-grass to herbicides detoxified by glutathione conjugation. Although herbicide-resistant populations show enhanced GST expression, in the case of fenoxaprop-ethyl the associated increased detoxifying activities alone cannot explain the differences between populations in the degree of resistance seen at the whole plant level. ©1997 SCI     

我国小麦田禾本科杂草对精噁唑禾草灵的抗药性研究进展

小麦是我国主要的粮食作物, 麦田草害的发生与危害严重影响小麦的产量与品质。我国小麦田的禾本科杂草主要包括日本看麦娘、看麦娘、菵草和多花黑麦草等, 田间杂草防除主要依靠化学除草剂。精噁唑禾草灵自20世纪80年代进入我国市场以来, 长期用于小麦田禾本科杂草防除, 已经报道麦田多种禾本科杂草对精噁唑禾草灵产生了高水平抗药性。为更加科学合理地控制小麦田杂草的发生与危害, 一些学者就麦田禾本科杂草对精噁唑禾草灵的抗药性水平监测和抗性机理进行了系统研究。本文系统总结了我国小麦田抗精噁唑禾草灵杂草的发生种群、抗性水平、靶标酶抗性机理与非靶标抗性机理, 还梳理了抗性杂草的交互抗性与多抗性发生情况, 分析了我国在抗性杂草治理方面的经验以及面临的问题, 为农田杂草防除提供指导。     

浙沪小麦田杂草调查及优势杂草化学防除技术研究

为了明确浙沪小麦田杂草发生情况及优势杂草控制技术,采用唐氏五级目测法和随机取样计数法相结合的方法,对上海和浙江的116块冬小麦田杂草进行了抽样调查,同时采用盆栽试验和田间小区试验测定了7种除草剂对主要危害杂草的防效。结果表明,浙沪冬小麦田共调查到杂草43种,隶属于14科,其中菊科杂草种类最多,有10种,其次是禾本科杂草9种,再次是石竹科杂草5种。杂草群落组成以禾本科杂草为主,优势杂草为日本看麦娘Alopecurus japonicus Steud.、菵草Beckmannia syzigachne(Steud.) Fern.、棒头草Polypogon fugax Nees ex Steud.、硬草Sclerochloa dura(L.) Beauv.、早熟禾Poa annua L.、鹅肠菜Myosoton aquaticum(L.) Moench、救荒野豌豆Vicia sativa L.、猪殃殃Galium spurium L.和小藜Chenopodium ficifolium Smith。室内除草活性及田间药效试验结果表明,日本看麦娘可用15%炔草酯WP、5%唑啉草酯EC、30 g/L...     

Sulfonylurea herbicide-resistant Monochoria vaginalis in Korean rice culture

Nine Monochoria vaginalis Pres1 accessions from Chonnam province, Korea were tested for resistance to the sulfonylurea herbicide, imazosulfuron, in whole-plant response bioassay. All accessions were confirmed resistant (R) to imazosulfuron. The GR50 (imazosulfuron concentration that reduced shoot dry weight by 50%) values of R accessions were 1112-3172 (accession #9) times higher than that of the standard susceptible (S) accession. Accession #9 exhibited cross-resistance to other sulfonylurea herbicides, bensulfuron-methyl, cyclosulfamuron and pyrazosulfuron-ethyl, but not to the imidazolinone herbicides, imazapyr and imazaquin. The R biotype could be controlled by other herbicides with different modes of action, such as mefenacet and pyrazolate, applied to soil at recommended rates. Foliar-applied herbicides, 2,4-D and bentazone, also controlled both the R and S biotypes. Sulfonylurea-based mixtures, except ethoxysulfuron plus fentrazamide, did not control resistant M. vaginalis. Rice yield was reduced 70% by resistant M. vaginalis that escaped pyrazosulfuron-ethyl plus molinate, compared with hand weeding in direct-seeded rice culture. In contrast, rice yield was reduced 44% by resistant M. vaginalis that survived the pyrazosulfuron-ethyl plus molinate treatment, compared with pyrazolate plus butachlor in transplanted rice culture. In vitro acetolactate synthase (ALS) activity of the R biotype was 183, 35, 130 and 31 times more resistant to imazosulfuron, bensulfuron-methyl, cyclosulfamuron and pyrazosulfuron-ethyl, respectively, than the S biotype. Imidazolinone herbicides, imazapyr and imazaquin had similar effect on in vitro ALS activity of the R and S biotypes. The in vivo ALS activity of the R biotype was also less affected than the S biotype by the sulfonylurea herbicides imazosulfuron and pyrazosulfuron-ethyl. Results of in vitro and in vivo ALS assays indicate that the resistance mechanism of M. vaginalis to sulfonylurea herbicides may be due, in part, to an alteration in the target enzyme, ALS. Since the level of resistance in the enzyme assay was much lower than that in the whole-plant assay, other mechanisms of resistance, such as herbicide metabolism, may be involved.     

The impact of altered herbicide residues in transgenic herbicide-resistant crops on standard setting for herbicide residues

The global area covered with transgenic (genetically modified) crops has rapidly increased since their introduction in the mid-1990s. Most of these crops have been rendered herbicide resistant, for which it can be envisaged that the modification has an impact on the profile and level of herbicide residues within these crops. In this article, the four main categories of herbicide resistance, including resistance to acetolactate-synthase inhibitors, bromoxynil, glufosinate and glyphosate, are reviewed. The topics considered are the molecular mechanism underlying the herbicide resistance, the nature and levels of the residues formed and their impact on the residue definition and maximum residue limits (MRLs) defined by the Codex Alimentarius Commission and national authorities. No general conclusions can be drawn concerning the nature and level of residues, which has to be done on a case-by-case basis. International residue definitions and MRLs are still lacking for some herbicide-crop combinations, and harmonisation is therefore recommended.     

Genetic diversity of herbicide-resistant and -susceptible Avena fatua populations in North Dakota and Minnesota

Genetic diversity within and among 20 herbicide-resistant (HR) and 16 herbicide-susceptible (HS) Avena fatua multi-field populations was determined using 82 polymorphic loci resulting from two intersimple sequence repeat (ISSR) primers and one long-primer random amplified polymorphic DNA (LP-RAPD) primer. Collections from the Red River Valley of North Dakota and Minnesota, sampled in 1964 and 2000, represented A. fatua populations before and after intensive exposure to herbicides. A 1995 collection from south-west North Dakota represented A. fatua exposed to low herbicide selection. Despite differences in years of herbicide exposure among collections, both HR and HS populations from every collection maintained nearly similar levels of ISSR and RAPD diversity. Genetic differentiation among populations (G_ST) varied from 11% to 13% among HR populations and from 9% to 16% among HS populations, indicating that 84–91% of total variation remained within HS or within HR populations. Minimal difference in gene diversity between HR and HS is consistent with multiple origins of resistance, where HR A. fatua most likely evolved from diverse founding individuals.     

Reduced translocation is involved in resistance to glyphosate and paraquat in Conyza bonariensis and Conyza canadensis from California

Resistance to glyphosate and paraquat has evolved in some populations of Conyza spp. from California, USA. This study evaluated whether herbicide absorption and translocation were involved in the mechanism of resistance to both herbicides. Three lines of each species were used: glyphosate‐paraquat‐susceptible (GPS), glyphosate‐resistant (GR) and glyphosate‐paraquat‐resistant (GPR). Radiolabelled herbicide was applied to a fully expanded leaf, and absorption and movement out of the treated leaf were monitored for up to 24 h for paraquat and 72 h for glyphosate. Plants treated with paraquat were incubated in darkness for the first 16 h and then subjected to light conditions. More glyphosate was absorbed in C. bonariensis (52.9–58.3%) compared with C. canadensis (28.5–37.6%), but no differences in absorption were observed among lines within a species. However, in both species, the GR and GPR lines translocated less glyphosate out of the treated leaf when compared with their respective GPS lines. Paraquat absorption was similar among lines and across species (71.3–77.6%). Only a fraction of paraquat was translocated in the GPR lines (3% or less) when compared with their respective GPS or GR lines (20% or more) in both species. Taken together, these results indicate that reduced translocation is involved in the mechanism of resistance to glyphosate and paraquat in C. bonariensis and C. canadensis.