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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 总被引：3，自引：0，他引：3
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。 相似文献
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寻找新的除草剂靶标酶一直是生物学家和农药化学家不断探索的课题,每当发现一个新的作用靶标,就会有一批新的除草剂问世,并带来一场化学除草的革命。如乙酰乳酸合成酶（ＡＬＳ）的发现,将除草剂推入到一个超高效的时代,并开发出磺酰脲类、咪唑啉酮类、磺酰胺类、三唑... 相似文献
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植物乙酰乳酸合成酶抑制剂作用方式及机理研究进展 总被引：2，自引：2，他引：0
以拟南芥Arabidopsis thaliana等植物为主要对象,系统评述了乙酰乳酸合成酶(ALS)抑制剂在作用靶标、选择性机制、毒性机理及化学杀雄作用等方面的研究进展。ALS是磺酰脲类、咪唑啉酮类等多种除草剂的共同作用靶标,最新研究又发现苯磺隆、酰嘧磺隆等多种ALS抑制剂可作为敏感植物的化学杀雄剂。目前该研究领域的薄弱环节是ALS抑制剂的毒性机理,先后提出了支链氨基酸饥饿、核酸合成受阻、ALS底物积累、养分转运障碍、无氧呼吸等假说,但均未能被证实。借助高通量的代谢组学、转录组学、蛋白质组学检测技术将能够更全面地揭示ALS抑制剂的生理生化效应,为研究其毒性机理提供新证据。 相似文献
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作用靶标为乙酰乳酸合成酶（ＡＬＳ）的除草剂近年有了长足的发展，由最初的磺酰脲类，咪唑啉酮类除草剂发展至今的三唑并嘧啶磺酰苯胺类，嘧啶氧代苯甲酸类等品种，这些新品种具有活性高，用药量极低，对哺乳动物低毒，对环境影响较小等优异的特点，近年开发的一些新品种正代表着未来除草剂的发展方向，本文介绍了近年世界各大公司新开发的ＡＬＳ抑制剂，并就其在中国的应用前景进行了讨论。 相似文献
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磺酰脲类除草剂的开发及在我国的应用 总被引：1，自引：0，他引：1
磺酰脲类是近10年来开发的一类超高效除草剂,每公顷用药量由传统除草剂的公斤级降到以克为单位:对哺乳动物、鱼类、鸟类低毒:因用药量极少,对环境的污染远低于传统的除草剂。此类除草剂通过叶面或根部进入植物体,并传导到全株,通过抑制乙酰乳酸合成酶(支链氨基酸-缬氨酸、亮氨酸和异亮氨酸生物合成的关键酶)的合成,从而阻止细胞分裂达到杀草目的。对多种一年生或多 相似文献
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利用异源表达于酵母细胞中的小麦细胞色素P450cDNA(CYP71C6v1)研究了磺酰脲类除草剂绿磺隆、醚苯磺隆的代谢作用。结果表明,代谢产物5-羟基绿磺隆和5-羟基醚苯磺隆能够抑制乙酰乳酸合成酶(ALS酶)活性,且代谢产物与母体化合物绿磺隆、醚苯磺隆抑制ALS酶活性的IC50值差异小,但是代谢产物在茎叶喷雾小麦和菜豆时,均未表现出活性。绿磺隆及其代谢产物抑制小麦ALS酶活性的IC50值分别为7.1×10-9和7.9×10-9mol/L,抑制菜豆ALS酶活性的IC50分别为3.6×10-9和4.1×10-9mol/L;醚苯磺隆及其代谢产物抑制小麦ALS酶活性的IC50分别为4.6×10-9和5.3×10-9mol/L,抑制菜豆ALS酶活性的IC50分别为4.7×10-9和4.9×10-9mol/L。结果表明,在磺酰脲类分子苯环5位上进行结构改造,有可能得到高活性的化合物。 相似文献
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荠菜对乙酰乳酸合成酶抑制剂类除草剂的抗性水平及其分子机制 总被引：1，自引：1，他引：0
为明确荠菜种群对苯磺隆的抗性水平及其靶标抗性产生的分子机制,采用整株水平测定法测定了荠菜对苯磺隆及其他5种乙酰乳酸合成酶（ALS）抑制剂类除草剂的抗性水平,同时扩增和比对了荠菜抗性和敏感种群之间ALS基因的差异。结果显示:与敏感种群15-ZMD-1相比,抗性种群15-ZMD-5对苯磺隆产生了高水平抗性,抗性倍数为219.6;15-ZMD-5种群不同单株中共存在3种突变方式,分别为ALS基因197位点脯氨酸（CCT）突变为亮氨酸（CTT）、574位点色氨酸（TGG）突变为亮氨酸（TTG）以及单株同时发生上述197和574位点的氨基酸突变。15-ZMD-5抗苯磺隆种群对嘧草硫醚、啶磺草胺和氟唑磺隆均产生了高水平的交互抗性,抗性倍数分别为41.2、79.3和87.8;对双氟磺草胺和咪唑乙烟酸产生了低水平的交互抗性,抗性倍数分别为8.5和5.6。分析表明,荠菜抗性种群ALS基因发生的氨基酸突变可能是导致其对ALS抑制剂类除草剂产生抗性的重要原因之一。 相似文献
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从2004年开始,延边地区稻田大量发生抗磺酰脲类除草剂苄嘧磺隆的抗药性生态型雨久花。为解析其抗药性突变机制,采用离体法测定了抗、感性雨久花乙酰乳酸合成酶活性。结果表明,抑制抗、感性雨久花乙酰乳酸合成酶活性50%的苄嘧磺隆剂量为253.44×10-7mol/L和2.80×10-7mol/L;抑制抗、感性雨久花乙酰乳酸合成酶活性50%的吡嘧磺隆剂量为1802.15×10-7mol/L和20.85×10-7mol/L。抗药性雨久花对苄嘧磺隆和吡嘧磺隆的抗性系数(RI50/SI50)值分别为90.6和86.5,并存在交互抗药性。确认抗药性突变系由其乙酰乳酸合成酶对磺酰脲类除草剂苄嘧磺隆、吡嘧磺隆反应钝化所致。 相似文献
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V Kati L Scarabel D Thiery‐Lanfranchi V Kioleoglou S Liberopoulou C Dlye 《Weed Research》2019,59(5):367-376
The issue of cross‐ or multiple resistance to acetolactate synthase (ALS) inhibitors and the auxinic herbicide 2,4‐D was investigated in Papaver rhoeas L., a common and troublesome weed in winter cereals, in a broad‐scale study across four European countries. A combination of herbicide sensitivity bioassays and molecular assays targeting mutations involved in resistance was conducted on 27 populations of P. rhoeas originating from Greece (9), Italy (5), France (10) and Spain (3). Plants resistant to the field rate of 2,4‐D were observed in 25 of the 27 populations assayed, in frequencies ranging from 5% to 85%. Plants resistant to ALS‐inhibiting herbicides (sulfonylureas) were present in 24 of the 27 populations, in frequencies ranging from 4% to 100%. Plants resistant to 2,4‐D co‐occurred with plants resistant to sulfonylureas in 23 populations. In four of these, the probability of presence of plants with cross‐ or multiple resistance to 2,4‐D and sulfonylureas was higher than 0.5. ALS genotyping of plants from the field populations or of their progenies, identified ALS alleles carrying a mutation at codon Pro197 or Trp574 in 2,4‐D‐sensitive and in 2,4‐D‐resistant plants. The latter case confirmed multiple resistance to 2,4‐D and ALS inhibitors at the level of individual plants in all four countries investigated. This study is the first to identify individual plants with multiple resistance in P. rhoeas, an attribute rarely assessed in other weed species, but one with significant implications in designing chemical control strategies. 相似文献
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Several UK populations of the grass weed Alopecurus myosuroides were identified where high proportions of individuals showed resistance to the acetolactate synthase (ALS)‐inhibiting herbicides, mesosulfuron‐methyl + iodosulfuron‐methyl sodium mixture and sulfometuron‐methyl. Screening with sulfometuron, followed by DNA sequencing of the ALS gene from resistant and susceptible individuals, led to the identification of eight populations where a single point mutation segregated with resistance to sulfometuron. All highly resistant individuals from seven of eight populations showed a single‐nucleotide polymorphism (SNP) in the first position of the Pro197 codon of an A. myosuroides ALS gene, conferring a predicted proline to threonine target‐site change. One population showed resistant individuals with single‐nucleotide polymorphism in the second position of the Trp574 codon, conferring a predicted tryptophan to leucine substitution. No other mutations segregating with resistance were found. Enzyme assays confirmed that resistance was due to an altered form of ALS enzyme, which was less susceptible to inhibition by sulfonylureas, making this one of the first fully characterised cases of ALS target‐site resistance in a European grass weed. Increased information regarding the nature and distribution of ALS target‐site mutation may help support sustainable management strategies, allowing continued use of mesosulfuron + iodosulfuron against this weed in the UK. 相似文献
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The development of acetolactate synthase (ALS) tolerant sugar beet provides new opportunities for weed control in sugar beet cultivation. The system consists of an ALS?inhibiting herbicide (foramsulfuron + thiencarbazone‐methyl) and a herbicide‐tolerant sugar beet variety. Previously, the use of ALS‐inhibitors in sugar beet was limited due to the susceptibility of the crop to active ingredients from this mode of action. The postulated benefits of cultivation of the ALS‐tolerant sugar beet are associated with potential risks. Up to now, with no relevant proportion of herbicide‐tolerant crops in Germany, ALS‐inhibitors are used in many different crops. An additional use in sugar beet cultivation could increase the selection pressure for ALS‐resistant weeds. To evaluate the impact of varying intensity of ALS‐inhibitor use on two weed species (Alopecurus myosuroides and Tripleurospermum perforatum) in a crop rotation, field trials were conducted in Germany in two locations from 2014 to 2017. Weed densities, genetic resistance background and crop yields were annually assessed. The results indicate that it is possible to control ALS‐resistant weeds with an adapted herbicide strategy in a crop rotation including herbicide‐tolerant sugar beet. According to the weed density and species, the herbicide strategy must be extended to graminicide treatment in sugar beet, and a residual herbicide must be used in winter wheat. The spread of resistant biotypes in our experiments could not be attributed to the integration of herbicide‐tolerant cultivars, although the application of ALS‐inhibitors promoted the development of resistant weed populations. Annual use of ALS‐inhibitors resulted in significant high weed densities and caused seriously yield losses. Genetic analysis of surviving weed plants confirmed the selection of ALS‐resistant biotypes. 相似文献
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Herbicide resistance in Lolium rigidum is widespread across much of the agricultural land in Australia. As the incidence of herbicide resistance has increased, so has the incidence of multiple herbicide resistance. This reduces the herbicide options available for control of this weed. This study reports on the successful amplification and sequencing of the acetolactate synthase (ALS) gene of L. rigidum using primers designed from sequence information of related taxa. This enables, for the first time, the successful determination of a mutation in the ALS gene of this species that provides resistance to ALS‐inhibiting herbicides. This mutation causes amino acid substitution at Trp574 (numbering standardised to Arabidopsis thaliana) to Leu which had been reported to confer a high level of resistance against all classes of ALS inhibitor herbicides. In addition, multiple resistance to ALS‐inhibiting and acetyl‐coenzyme A carboxylase‐inhibiting herbicides is acquired through the independent accumulation of mutant alleles for the target sites. This may thus explain some of the irregular, mosaic resistance patterns that occur in this predominantly outcrossing species. 相似文献
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The joint action of soil-applied herbicide mixtures with similar or different modes of action has been assessed by using the additive dose model (ADM). The herbicides chlorsulfuron, metsulfuron-methyl, pendimethalin and pretilachlor, applied either singly or in binary mixtures, were used on rice (Oryza sativa L.). The growth (shoot) response curves were described by a logistic dose-response model. The ED50 values and their corresponding standard errors obtained from the response curves were used to test statistically if the shape of the isoboles differed from the reference model (ADM). Results showed that mixtures of herbicides with similar molecular targets, i.e. chlorsulfuron and metsulfuron (acetolactate synthase (ALS) inhibitors), and with different molecular targets, i.e. pendimethalin (microtubule assembly inhibitor) and pretilachlor (very long chain fatty acids (VLCFAs) inhibitor), followed the ADM. Mixing herbicides with different molecular targets gave different results depending on whether pretilachlor or pendimethalin was involved. In general, mixtures of pretilachlor and sulfonylureas showed synergistic interactions, whereas mixtures of pendimethalin and sulfonylureas exhibited either antagonistic or additive activities. Hence, there is a large potential for both increasing the specificity of herbicides by using mixtures and lowering the total dose for weed control, while at the same time delaying the development of herbicide resistance by using mixtures with different molecular targets. 相似文献
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Ten accessions of sulfonylurea‐resistant Schoenoplectus juncoides were collected from paddy fields in Japan. In order to characterize acetolactate synthase from sulfonylurea‐resistant S. juncoides, acetolactate synthase amino acid substitutions, whole‐plant growth inhibition and acetolactate synthase enzyme inhibition were examined. Schoenoplectus juncoides has two acetolactate synthase genes (ALS1 and ALS2). The sulfonylurea‐resistant accessions harbored amino acid substitutions at Pro197 or Trp574 in either ALS1 or ALS2 (the amino acid number is standardized to the Arabidopsis thaliana sequence). The whole plants of all the sulfonylurea‐resistant accessions showed resistance to imazosulfuron. The resistance level depended on the altered amino acid residues in acetolactate synthase. The acetolactate synthase enzyme that was partially purified from all the sulfonylurea‐resistant accessions was less sensitive to imazosulfuron, compared to the susceptible accession, suggesting that the resistance is related to the altered acetolactate synthase enzyme. In addition, the concentration–response inhibition of acetolactate synthase activity by imazosulfuron in the sulfonylurea‐resistant accessions was remarkably different with the presence of an amino acid substitution in either ALS1 or ALS2. Furthermore, the concentration–response inhibition of acetolactate synthase activity in the sulfonylurea‐resistant accessions with a P197S, P197T or W574L mutation showed a double‐sigmoid curve. The regression analysis of enzyme inhibition suggested that the abundance ratio of ALS1 to ALS2 enzymes was approximately 70:30%, with a range of ±15%. Taken together, these results suggest that the resistance of sulfonylurea‐resistant accessions of S. juncoides is related to altered acetolactate synthase in either ALS1 or ALS2, although the abundance of the altered acetolactate synthase in the plants is different among the sulfonylurea‐resistant accessions. 相似文献
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Guang-Xi Wang Mui-Keng Tan Hiromasa Saitoh Toshiyuki Imaizumi Tohru Tominaga 《Pesticide biochemistry and physiology》2007,88(2):143-148
TILLING (Targeting Induced Local Lesions IN Genomes) is a powerful reverse genetic technique that employs a mismatch-specific endonuclease to discover induced point mutations in genes of interest. The use of the TILLING technique to survey natural variation in genes is called Ecotilling. We report an adaptation of Ecotilling for rapid detection of single-nucleotide mutations in the acetolactate synthase (ALS) genes of sulfonylurea (SU)-resistant (R) Monochoria vaginalis (Pontederiaceae), a paddy weed, in Japan. Genomic DNA of a SU-R plant (target DNA) was mixed with the DNA of a SU-susceptible (S) plant (reference DNA). Ecotilling detected two nucleotide mutations in the ALS gene of SU-R M. vaginalis. These 2 mutations were confirmed by DNA sequencing. A single nucleotide mutation (C to A), in the codon CCT to CAT and another mutation (C to T), in the codon CCT to TCT were identified by sequencing. Both mutations result in the disruption of a Pro codon in the conserved Domain A region with the consequent substitution of a His residue in the first mutation and a Ser residue in the second. Substitution of the Pro residue in Domain A of the ALS gene has been reported to result in insensitivity to SUs in many weed biotypes. This study demonstrates that Ecotilling is a fast, reliable, economical method for detecting single-nucleotide mutations in genes arising from herbicide selection. 相似文献
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In 2003, a random survey was conducted across the Western Australian wheatbelt to establish the extent and frequency of herbicide resistance in Raphanus raphanistrum populations infesting crop fields. Five hundred cropping fields were visited, with 90 R. raphanistrum populations collected, representative of populations present in crop fields throughout the Western Australian wheatbelt. Collected populations were screened with four herbicides of various modes of action that are commonly used for the control of this weed. The majority of Western Australian R. raphanistrum populations were found to contain plants resistant to the acetolactate synthase (ALS)‐inhibiting herbicide chlorsulfuron (54%) and auxin analogue herbicide, 2,4‐D amine (60%). This survey also determined that over half (58%) of these populations were multiple resistant across at least two of the four herbicide modes of action used in the screening. Only 17% of R. raphanistrum populations have retained their initial status of susceptibility to all four herbicides. The distribution patterns of the herbicide‐resistant populations identified that there were higher frequencies of resistant and developing resistance populations occurring in the intensively cropped northern regions of the wheatbelt. These results clearly indicate that the reliance on herbicidal weed control in cropping systems based on reduced tillage and stubble retention will lead to higher frequencies of herbicide‐resistant weed populations. Therefore, within intensive crop production systems, there is a need to diversify weed management strategies and not rely entirely on too few herbicide control options. 相似文献
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《Pesticide biochemistry and physiology》2003,75(1-2):39-46
Responses of acetolactate synthase (ALS) from grass and broadleaf weed to sulfonylurea (SU) herbicide were compared in relation to the leaf position in a seedling and seedling age. The responses of Echinochloa crus-galli (L.) P. Beauv. and Eclipta prostrata L., dominant grass and broadleaf weed in paddy fields in Korea, respectively, to azimsulfuron were examined. In this study, in vivo ALS assay was used to verify the responsibility of selected weed species at different leaf stages to SU-herbicides. The data from in vivo ALS assay could be used for discriminating the degree of tolerance between weeds showed different susceptibility. In E. crus-galli and E. prostrata there was no apparent relationship between the chlorophyll concentrations and herbicide concentrations treated on leaves. Both in E. crus-galli and E. prostrata, the free amino acid concentrations, however, were increased as herbicide concentration increased in the younger leaves. The free amino acid concentrations were generally higher in older leaves than young leaves and were significantly increased concomitantly with increasing herbicide concentration. The ALS activity was decreased rapidly with higher azimsulfuron rates in old but not senescent leaves compared to juvenile leaves. Generally, ALS activity was less sensitive at the early leaf stage than late leaf stage. The activity of ALS in E. prostrata was highly responsive to application time and more susceptible to the herbicide as compared to E. crus-galli. The highest levels of acetoin were observed in the uppermost and youngest leaf in all species tested. 相似文献
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Herbicides that target the acetolactate synthase (ALS) are among the most widely used weed control chemicals since their introduction into the marketplace in the early 1980s, including five classes (sulfonylureas, imidazolinones, triazolopyrimidines, pyrimidinylthio (or oxy)-benzoates and sulfonylamino-carbonyltriazolinones). The mechanism researches have progressed unprecedentedly in the last two decades. Primary mode of action of the ALS-inhibiting herbicides that interfere with the activity of ALS enzyme seems no longer in doubt. Three lines of investigation from physiology, genetics, molecular and chemical structure aspects came together to prove that ALS is the site of action. Researches on the effects of branched chain amino acids (BCAAs) synthesis or protein metabolism caused by ALS-inhibiting herbicide elicit lots of disputations. Besides these two main works, other secondary effects of ALS inhibition, such as buildup of 2-ketobutyrate (α-ketobutyrate or 2-KB) or 2-aminobutyrate (2-AB, the transamination product of 2-KB), depletion of intermediates of the pathway for some critical processes, disruption of photosynthesis transport and respiration system etc., have also been implicated in the mechanism of plant death. However, there are still some disputations and doubts on the precise mechanisms that need further probing into. Further more, as many ALS-inhibiting herbicides and their derivatives are chiral with one or even more enantiomers, which may behave quite differently in biochemical processes, the effects and the environmental fate of chiral herbicides need to be investigated stereospecifically. By this, we can have a better understanding about the herbicides and avoid unnecessary pollution load. 相似文献