磺酰脲类除草剂的微生物降解研究进展

磺酰脲类除草剂是使用最广泛的除草剂之一。微生物降解是磺酰脲类除草剂在土壤中降解的重要方式。本文简要概述了土壤微生物对磺酰脲类除草剂的降解、降解机理及影响微生物降解磺酰脲类除草剂的因素。     

除草剂靶酶-AHAS酶及基因突变体与除草剂设计(Ⅱ).AHAS及W464突变酶与除草活性分子的相互作用

乙酰羟基酸合成酶(AHAS)是磺酰脲类、咪唑啉酮类、三唑嘧啶磺酰胺类及水杨酸类除草剂的作用靶标,大田使用中杂草对这几类除草剂产生抗性的主要因素是AHAS酶的突变。利用大肠杆菌AHAS Ⅱ中464位的色氨酸突变体(W464A、W464F、W464L、W464Y),研究了野生型和突变酶对商品化除草剂(氯嘧磺隆、氯磺隆、咪唑乙烟酸、咪唑喹啉酸)以及烷硫基磺酰脲的敏感性。野生型E. coli AHAS Ⅱ对这些化合物的抑制作用较为敏感,而突变酶对其呈现出不同程度的抗性,使商品化除草剂的抑制常数增加了10~1.0×104倍不等,烷硫基磺酰脲的抑制常数增加幅度较小。烷硫基磺酰脲 1a 对W464L突变酶的高抑制活性,暗示着发展针对靶酶抗性的除草剂的可能性。     

磺酰脲类除草剂的使用与杂草抗药性

1970年首次报道了杂草对均三氮苯类除草剂产生抗性,杂草对除草剂的抗性也随着除草剂的使用而不断发展与蔓延。到目前为止,已有100种以上杂草对不同类型除草剂产生了抗性,其中涉及均三氮苯、联吡啶、苯氧羧酸、苯基脲、二硝基苯胺、芳氧苯氧丙酸、环己烯酮、三唑、咪唑啉酮、磺酰脲等,从而使杂草抗性成为除草剂品种开发及化学除草中的重要问题。在杂草对众多类型除草剂产生抗性的事例中,杂草对超高效除草剂磺酰脲类化合物的抗性最引人注目。     

杂草对磺酰脲类除草剂抗性的研究动态

杂草对磺酰脲类除草剂抗性的研究动态刘东卫，闻永星（江苏省农科院杂草研究中心南京２１００１４）（安徽白湖）磺酰脲类除草剂的开发始于７０年代末期。由于其具有极高的活性，杀草谱广，选择性强，标志除草剂新品种的开发进入了“超高效阶段”。正是由于这类除草剂的优...     

三唑并嘧啶磺酰胺类除草剂的研究概况

三唑并嘧啶磺酰胺类除草剂是将磺酰脲类除草剂通过脲桥的结构改造和修饰而得,它既保持了磺酰脲类除草剂的超高效性,又克服了一些磺酰脲类除草剂品种在土壤中残留期较长、易对后茬作物造成伤害等缺点。本文综述了三唑并嘧啶磺酰胺类除草剂的结构、主要品种、作用机理、应用研究和发展前景。     

延边地区稻田抗药性杂草防除技术研究

2002年在延边稻区首次发现抗磺酰脲类除草剂慈姑以来,稻田陆续出现抗磺酰脲类除草剂的雨久花、藨草、牛毛毡和抗二氯喹磷酸的稻稗生态型。其中,抗性藨草和稻稗生态型仍处于蔓延状态。抗药性特征的分析结果,抗性稻稗生态型的抗二氯喹磷酸程度因地而异,高抗生态型的抗性系数(R90/S90)达到60。在标准使用剂量条件下,有效防除抗二氯喹磷酸稻稗生态型的除草剂有氰氟草酯、五氟磺草胺、丙草胺、丁草胺;有效防除抗磺酰脲类除草剂的慈姑、雨久花、藨草、牛毛毡生态型的除草剂有灭草松、2甲4氯、五氟磺草胺、嘧啶肟草醚、吡唑特。     

磺酰脲类除草剂与杂草对其抗性的研究进展

1磺酰脲类除草剂的概况1.1磺酰脲类除草剂的发展20世纪70年代末,美国杜邦公司Levitt等首次开发和报道了磺酰脲类除草剂绿磺隆的除草活性[1]。80年代初,这一除草剂开始进行大规模商品化生产,此后,又不断研制和开发了许多磺酰脲类除草剂新品种。此类除草剂问世以后,以其活性高、选择性强、杀草谱广及对动物安全等特性在世界各地得到广泛应用。目前有关磺酰脲类除草剂的专利有400多项,已商品化的有30多种。这类除草剂有很高的除草效率,用量一般为2~100 g/hm2,比传统除草剂的除草效率高100~1 000倍[2]。磺酰脲类除草剂对动物低毒,在非靶标生物…     

微生物降解磺酰脲类除草剂的研究进展

磺酰脲类除草剂具有高效和高选择性等优点,但其微量残留在土壤环境中就会对敏感作物会产生药害。因此,解决其残留问题便成为当今的研究热点。其中微生物降解是磺酰脲类除草剂降解的最有效方法之一。本文综述了降解磺酰脲类除草剂微生物种类、降解机理及研究现状,并展望了微生物降解磺酰脲类除草剂修复污染土壤的前景。     

除草剂与乙酰乳酸合成酶相互作用的分子机理研究进展

综述了酵母乙酰乳酸合成酶(ScALS)与磺酰脲类除草剂氯嘧磺隆(chlorimuron-ethyl,CE)形成的复合物在0.28 nm分辨率下的晶体结构及拟南芥乙酰乳酸合成酶(AtALS)与磺酰脲类和咪唑啉酮类除草剂复合物的三维结构。除草剂的分子结构与酶、底物并不相似,但它们与酶形成的复合物可阻断底物进入酶活性位点通路而起抑制作用。连接磺酰脲的10个氨基酸残基同样连接咪唑喹啉酸,另有6个残基只与磺酰脲而不与咪唑喹啉酸相连,有2个残基只与咪唑喹啉酸而不与磺酰脲相连,即两种抑制剂占据了特别的重叠位点,但以不同方式连接。抗性杂草的产生是因为突变株ALS的残基位点变异,从而引起除草剂与ALS结合方式的变化。这些研究对进一步理解除草剂与靶分子的作用方式及除草剂的分子药物设计具有重要的指导作用。     

磺酰脲类除草剂的降解机制及代谢产物的研究进展

磺酰脲类除草剂是一类高效,低毒和高选择性的除草剂,该类除草剂能有效防除阔叶杂草,其中有些品种对禾本科杂草也有一定的抑制作用。但同时因其用量低、对哺乳动物低毒以及独特的除草活性等特点而得到广泛应用。因此,了解磺酰脲类除草剂在土壤中的环境行为及归趋对于其科学合理使用、防止作物药害和保护农业生态环境具有非常重要的意义。根据笔者对磺酰脲类除草剂的深入研究,并总结归纳国内外的相关文献报道,对磺酰脲类除草剂的降解机制及其代谢产物的研究进行了综述,最后展望了磺酰脲类除草剂未来的发展趋势。     

Sulfonylurea herbicide resistance in Sonchus asper biotypes in Alberta, Canada

Summary Two Sonchus asper (spiny annual sow-thistle) biotypes, suspected of being resistant to the sulfonylurea herbicide metsulfuron-methyl, were collected in 1996 from two barley ( Hordeum vulgare ) fields in central Alberta, Canada. Both fields had received at least six applications of acetolactate synthase (ALS)-inhibiting herbicide(s). The responses of the two resistant (R) biotypes and two susceptible (S) biotypes to several sulfonylurea herbicides, and to herbicides and herbicide mixtures with other mechanisms of action, were compared. Both R biotypes were highly resistant to all sulfonylurea herbicides, but their control with other herbicides and mixtures was effective and comparable to that of the S biotypes. ALS extracted from an R biotype was about 440 times more resistant to metsulfuron-methyl than that of an S biotype, indicating that resistance was conferred by an ALS enzyme that was less sensitive to inhibition by the herbicide. Competitiveness and seed production of S. asper varied among biotypes, but the differences were probably the result of ecotype differences rather than resistance or susceptibility to sulfonylurea herbicides. This is the first reported occurrence of target site-based S. asper resistance to ALS-inhibiting herbicides.     

Cross-resistance pattern and alternative herbicides for Cyperus difformis resistant to sulfonylurea herbicides in Korea

A Cyperus difformis L accession from Chonnam province, Korea was tested for resistance to the sulfonylurea herbicide, imazosulfuron. The accession was confirmed to be resistant (R) and was cross-resistant to other sulfonylurea herbicides, bensulfuron-methyl, cyclosulfamuron and pyrazosulfuron-ethyl, the pyrimidinyl thiobenzoate herbicide, bispyribac-sodium, and the imidazolinone herbicide imazapyr, but not to imazaquin. Multiple resistance was tested using twelve herbicides with target sites other than acetolactate synthase (ALS). The R biotype could be controlled by other herbicides with different modes of action such as butachlor, carfentrazone-ethyl, clomeprop, dithiopyr, esprocarb, mefenacet, oxadiazon, pretilachlor, pyrazolate and thiobencarb, applied to soil at recommended rates. Several sulfonylurea herbicide-based mixtures can control both the R and S biotypes of C difformis, except sulfonylurea plus dimepiperate, molinate or pyriftalid, and pyrazolate plus butachlor. Although mixtures of sulfonylurea herbicides might be more effective, they should be avoided and used only in special cases. In terms of in vitro ALS activity, the R biotype was 1139-, 3583-, 1482-, 416-, 5- and 9-fold more resistant to bensulfuron-methyl, cyclosulfamuron, imazosulfuron, pyrazosulfuron-ethyl, bispyribac-sodium and imazapyr, respectively, than the S biotype. The in vivo ALS activity of the R biotype was also less affected by the sulfonylurea herbicides, imazosulfuron and pyrazosulfuron-ethyl, than the S biotype. Results of in vitro and in vivo ALS assays indicated that the resistance mechanism of C difformis to ALS inhibitor herbicides was primarily due to an alteration in the target enzyme, ALS. Greenhouse experiments showed delayed flowering and reduced seed production of the R biotype, which could possibly result in reduced fitness. This unusual observation needs to be confirmed in field situations.     

Identification of resistance to either paraquat or ALS-inhibiting herbicides in two Western Australian Hordeum leporinum biotypes

BACKGROUND: Hordeum populations are becoming increasingly difficult to control in cropping fields. Two herbicide‐resistant H. leporinum populations were identified during a random crop survey after herbicides were applied. The study aimed to determine the herbicide resistance profile of these H. leporinum biotypes to a range of herbicides used for their control. RESULTS: Based on dose–response studies, one H. leporinum population was very highly resistant to sulfosulfuron and sulfometuron (both sulfonylurea herbicides) and also displayed low‐level resistance to imazamox (an imidazolinone herbicide). Reduced sensitivity of the ALS enzyme was identified with in vitro activity assays. Gene sequence analysis revealed a proline‐to‐threonine substitution at amino acid position 197 of ALS, which is likely to be the molecular basis for resistance in this population. Herbicide screening also revealed a different H. leporinum population with resistance to the bipyridyl herbicide paraquat. CONCLUSION: This study established the first cases of (1) sulfonylurea‐to‐imidazolinone cross‐resistance and (2) field‐evolved paraquat resistance in a Hordeum species in Western Australia. Copyright © 2012 Society of Chemical Industry     

Sulfonylurea resistance in Stellaria media [L.] Vill.

A sulfonylurea resistant biotype of common chickweed (Stellaria media L. Vill.) was found in a field treated with chlorsulfuron or metsulfuron for eight consecutive years. In pot experiments the biotype was resistant to postemergence treatments with the following acetolactate synthase (ALS) inhibitors: chlorsulfuron, metsulfuron, tribenuron, triasulfuron, rimsulfuron, sulfometuron, flumetsulam and imazapyr. The level of resistance to chlorsulfuron and sulfometuron was higher than to the other sulfonylurea herbicides. Whereas the level of cross resistance to the triazolopyrimidine herbicide, flumetsulam was comparable to that of metsulfuron, that of imazapyr was significantly lower. In contrast to imazapyr the biotype was not resistant to imazethapyr, an other imidazolinone herbicide. ALS in vitro assays revealed that resistance was due to an ALS enzyme that was less sensitive to ALS inhibiting herbicides. Herbicides with different modes of action were equally effective on the susceptible and resistant biotypes.     

A molecular genetic assessment of herbicide-resistant Sinapis arvensis

The acquisition of resistance to both the auxinic herbicide dicamba and the sulfonylurea herbicide chlorsulfuron has been recorded in Canadian populations of the weed species Sinapis arvensis L. (charlock, wild mustard) To study the effect of this selection for herbicide resistance on levels of genetic variation, polymerase chain reaction-based DNA fingerprinting techniques were used to characterize two herbicide-resistant and one susceptible population of S. arvensis . Analysis of the resultant DNA marker profiles revealed extensive polymorphism between individuals. However, segregation of the three biotypes was detectable despite high levels of intrabiotype polymorphism. No reduction in the levels of heterozygosity within the resistant populations were found compared with the susceptible population.     

Sulfonylurea resistance in Lindernia micrantha, an annual paddy weed in Japan

Resistance to sulfonylurea herbicides, including bensulfuron-methyl, pyrazosulfuron-ethyl, imazosulfuron and ethoxysulfuron, was discovered in naturally occurring populations of Lindernia micrantha D. Don in rice fields that had been treated with sulfonylurea-based herbicides for 3–7 consecutive years. The resistant biotype was approximately 80≈300 times more resistant than the susceptible one to the above four sulfonylurea herbicides. This is the second confirmed occurrence of herbicide resistance resulting from the use of sulfonylurea herbicides in Japan. Several herbicides with different modes of action, including pretilachlor, cafenstrole, bifenox, naproanilide, thiobencarb + simetryn + MCPB, MCPA-thioethyl + simetryn and cyhalofop-butyl + bentazone, effectively controlled the resistant biotype in pot trials.     

磺酰脲类除草剂的高效液相色谱法残留检测技术的研究进展

近年来,国内外学者对各环境介质中的磺酰脲类除草剂残留检测技术做了大量的研究,本文综述了高效液相色谱法在磺酰脲类除草剂残留检测方面的研究进展。     

Relationships between sulfonylurea herbicide treatment of host plants and the performance of herbivorous insects

Previous work had shown that the sulfonylurea herbicide chlorsulfuron affected the survival of a herbivorous insect species dwelling on a sub-lethally exposed host plant. Further experiments have been conducted to establish whether this negative effect was a single occurrence characteristics for the specific insect-plant interaction and the specific herbicide tested. Three insect-plant interactions were tested for the effects of selected sulfonylurea herbicides, i.e. metsulfuron-methyl, chlorsulfuron and tribenuron-methyl. The species pairs tested were Pieris brassicae/Brassica napus, Gastrophysa polygoni/Fallopia convolvulus and Sitobium avenae/Triticum aestivium. No significant effects on survival and relative growth rate of P brassicae or G polygoni were found when treating the host plants with sulfonylurea herbicides. However, the host plants had a significantly reduced root and shoot growth rate when treated with herbicide. Treating T aestivium with the recommended field rate of metasulfuron-methyl did not cause any change in development time, growth rate or fecundity of S avenae feeding on the host plants. The data presented suggest that the increased mortality observed for G polygoni larvae feeding on chlorsulfuron-treated host plants observed earlier was characteristic for this herbicide and for the specific plant-insect interaction only.     

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.     

Molecular characterisation of resistance to ALS-inhibiting herbicides in Hordeum leporinum biotypes

BACKGROUND: The acetolactate synthase (ALS)-inhibiting herbicide sulfosulfuron is registered in Australia for the selective control of Hordeum leporinum Link. in wheat crops. This herbicide failed to control H. leporinum on two farms in Western Australia on its first use. This study aimed to determine the level of resistance of three H. leporinum biotypes, identify the biochemical and molecular basis and develop molecular markers for diagnostic analysis of the resistance. RESULTS: Dose-response studies revealed very high level (>340-fold) resistance to the sulfonylurea herbicides sulfosulfuron and sulfometuron. In vitro ALS assays revealed that resistance was due to reduced sensitivity of the ALS enzyme to herbicide inhibition. This altered ALS sensitivity in the resistant biotypes was found to be due to a mutation in the ALS gene resulting in amino acid proline to serine substitution at position 197. In addition, two- to threefold higher ALS activities were consistently found in the resistant biotypes, compared with the known susceptible biotype. Two cleaved amplified polymorphic sequence (CAPS) markers were developed for diagnostic testing of the resistant populations. CONCLUSION: This study established the first documented case of evolved ALS inhibitor resistance in H. leporinum and revealed that the molecular basis of resistance is due to a Pro to Ser mutation in the ALS gene.