草甘膦作用机制和抗性研究进展

草甘膦是迄今为止最为重要、应用最广泛和最优秀的除草剂之一。然而,由于抗草甘膦转基因作物的广泛商业化导致草甘膦使用量迅速增长,杂草抗药性发生,这不仅对草甘膦的药效发挥和未来可持续应用造成了严重影响,而且对现代农业生产安全构成了威胁。本文通过对草甘膦的作用机理、草甘膦抗性杂草发展现状和抗性机制进行系统的总结和分析,以期为我国草甘膦的抗性研究和科学使用提供参考。     

抗草甘膦杂草的抗性机理研究进展

草甘膦因其独特而优异的理化特性,自上市起便受到广泛的关注,现在已经成为全世界应用最广的除草剂之一.但是随着草甘膦抗性杂草的不断出现,草甘膦的应用前景受到严峻的挑战.文章综述了草甘膦生产及应用现状、草甘膦作用机理和草甘膦抗性杂草的发展,重点阐述了草甘膦抗性杂草的抗性机理.最后对如何通过延缓草甘膦抗性杂草的出现,保护草甘膦提出建议.     

草甘膦抗性杂草的田间监测

北京的大兴区北藏村镇巴园子村的苦菜、节节草对草甘膦不敏感,防效仅为40%~60%;顺义区木林镇魏家店村的马唐对草甘膦不敏感,防效仅70%;通州区潞城镇小营村的藜对草甘膦不敏感,防效仅50%;延庆县井庄镇二司村的黄花蒿、刺儿菜、狗尾草、苦荬菜对草甘膦不敏感,防效仅40%~60%;延庆县农场的黄花蒿、刺儿菜、紫花地丁、苦荬菜对草甘膦不敏感,防效仅30%~50%;山东省淄博的铁苋菜对草甘膦不敏感,防效为70%;滕州的小飞蓬、苘麻、葎草对草甘膦不敏感,防效为40%~60%;广西的杂草对草甘膦都比较敏感,防效都在88%以上;其他杂草对草甘膦较敏感。     

对草甘膦有恶性抗性杂草的铲除方案

<正>1草甘膦抗性现状及面临的其他问题草甘膦为内吸传导型慢性广谱灭生性除草剂,主要抑制植物物体内烯醇丙酮基莽草素磷酸合成酶(EPSP),从而抑制莽草素向苯丙氨酸、酪氨酸及色氨酸的转化,使蛋白质的合成受到干扰,从而导致植物死亡。由于草甘膦优异的杀草活性、广泛的杀草谱、较低的土壤残留、较长的控草时间,加上抗除草剂转基因作物的广泛种植,使其成为全球销量第一的除草剂品种。然而由于长时间大量单一连续使用草甘膦,杂草的抗性问题已经非常突出。到目前已经公布了有31种     

广西进口粮谷中2种苋属杂草草甘膦抗性测定

为了解进境粮食中常见苋属杂草的抗草甘膦水平,采用整株检测法检测了主要进口粮谷携带的和广西境内的刺苋、反枝苋的草甘膦抗性。检测结果表明:在外来杂草的对比中,巴西大豆中的刺苋以及加拿大油菜籽中的反枝苋对草甘膦抗性强;大部分外来苋属杂草比国内苋属杂草对草甘膦的抗性强。     

巴斯夫问卷揭示美国草甘膦抗性

由巴斯夫开展的美国农户调查问卷发现,一半以上的调查对象承认他们的田间存在抗草甘膦的杂草。巴斯夫指出,80%以上的调查对象称他们愿意投入更多的资金控制这些具有抵抗性的杂草。     

美国发现新型抗性杂草

在美国内布拉斯加州一块种子用玉米生产土地上,发现一簇水萱麻杂草对苗后HPPD抑制类除草剂（如：Callisto,Laudis和Impact）产生抗性。这里已经连续5年反复使用这些HPPD抑制类除草剂。除了那些已经在该地发现的对草甘膦产生抗性的杂草如杉叶藻（marestail）、三裂豚草（giant ragweed）、地肤（kochia）,这是该州出现的新杂草抗性类型。     

2017年全球草甘膦市场规模有望达到135万t

据Global Industry Analysts的调研公司分析,全球草甘膦市场有望在2017年达到135万t的规模,耐草甘膦转基因作物的大量种植,免耕或少耕型农业耕作体系的大量推广,生物燃料作物的种植,以及草甘膦这个产品本身的不可替代性,将在未来几年内推动这个市场的增长。     

全球抗草甘膦杂草的发生概况与检疫思考

随着草甘膦在全球范围内的大量使用,杂草对草甘膦的抗药性也不断增强,给农业生产带来了严重的经济损失。本文综述了草甘膦的作用机理和杂草产生抗性的机制,重点阐述了多种草甘膦抗性杂草发生、分布与扩散概况;统计了我国在进口货物中截获与产生抗药性杂草同种类同来源国杂草的数据,分析了抗药性杂草随进口货物传入我国的风险;针对为何要加强抗药性杂草的检疫工作给出理由,并对预防抗药性杂草传入提出了几点建议。     

苏门白酒草对草甘膦等除草剂的多抗性检测及防治药剂筛选

苏门白酒草Conyza sumatrensis是中国华南地区常见的阔叶杂草,在果园和非耕地常造成严重危害。本研究采用整株剂量反应法,明确了采自广东省广州市的苏门白酒草疑似抗性种群 (GZ-R) 对草甘膦、百草枯和敌草快的抗性水平,比对了GZ-R种群和采自广东省清远市的敏感对照种群 (QY-S) 的草甘膦靶标酶基因EPSPS2片段的差异,并测定了灭草松、氯氟吡氧乙酸等5种茎叶处理剂对不同叶龄苏门白酒草的室内防除效果。结果表明:GZ-R种群对草甘膦和百草枯分别产生了中等水平和高水平抗性,并已对敌草快产生交互抗性,3种药剂对GZ-R种群的LD₅₀值分别是对QY-S种群LD₅₀值的7.2、72.3和6.6倍;与QY-S种群相比,GZ-R种群的EPSPS2基因106位由脯氨酸突变为苏氨酸。在灭草松、氯氟吡氧乙酸或2甲4氯钠推荐剂量下,于4~5叶期施药,苏门白酒草死亡率均为100%,但于6~7叶期和10~12叶期施药,苏门白酒草死亡率显著下降至44.4%~91.7%;而在草铵膦或苯嘧磺草胺推荐剂量下,不同叶龄期施药苏门白酒草的死亡率均为100%,因此在植株生长早期可使用草铵膦和苯嘧磺草胺防除已对草甘膦和百草枯等除草剂产生抗性的苏门白酒草。     

Glyphosate-resistant horseweed made sensitive to glyphosate: low-temperature suppression of glyphosate vacuolar sequestration revealed by 31P NMR

BACKGROUND: Horseweed has been the most invasive glyphosate‐resistant (GR) weed, spreading to 16 states in the United States and found on five continents. The authors have previously reported that GR horseweed employs rapid vacuolar sequestration of glyphosate, presumably via a tonoplast transporter, substantively to reduce cytosolic glyphosate concentrations. 1 It was hypothesized that glyphosate sequestration was the herbicide resistance mechanism. If resistance is indeed endowed by glyphosate sequestration, suppression of sequestration offers the potential for controlling GR horseweed at normal herbicide field‐use rates. RESULTS: Low‐temperature ³¹P NMR experiments performed in vivo with GR cold‐acclimated horseweed showed markedly suppressed vacuolar accumulation of glyphosate even 3 days after glyphosate treatment. [In stark contrast, 85% of the visible glyphosate was sequestered 24 h after spraying warm‐acclimated GR horseweed.] Cold‐acclimated GR horseweed treated at normal use rates and maintained at low temperature succumbed to the lethal effects of glyphosate over a 40 day period. Treatment of GR horseweed in the field when temperatures were cooler showed the predicted positive herbicidal response. CONCLUSIONS: Low temperature markedly diminishes vacuolar sequestration of glyphosate in the GR horseweed biotype, yielding a herbicide response equivalent to that of the sensitive biotype. This supports the recent hypothesis 1 that glyphosate sequestration is the resistance mechanism employed by GR horseweed. Copyright © 2011 Society of Chemical Industry     

Specific microbial responses to herbicides*

Examples from the literature and from the authors’own laboratory demonstrate that herbicides can exert adverse effects on the soil micro-flora, depending on concentration, though often at higher rates than the herbicidal dose. Examples refer to changes in microbial growth (asulam, linuron, paraquat) and equilibrium (metoxuron), respiration and nitrification in samples from field experiments (linuron, simazine) and laboratory experiments (bentazone, glyphosate, barban, etc.), enzyme activities (urease, phosphatase; barban, chlorpropham, linuron) and the decay of sprayed vegetation (glyphosate, paraquat).     

Simulation modelling to understand the evolution and management of glyphosate resistance in weeds

BACKGROUND: A simulation model is used to explore the influence of biological, ecological, genetic and operational (management) factors on the probability and rate of glyphosate resistance in model weed species. RESULTS: Glyphosate use for weed control prior to crop emergence is associated with low risks of resistance. These low risks can be further reduced by applying glyphosate in sequence with other broad-spectrum herbicides prior to crop seeding. Post-emergence glyphosate use, associated with glyphosate-resistant crops, very significantly increases risks of resistance evolution. Annual rotation with conventional crops reduces these risks, but the proportion of resistant populations can only be reduced to close to zero by mixing two of three post-emergence glyphosate applications with alternative herbicide modes of action. Weed species that are prolific seed producers with high seed bank turnover rates are most at risk of glyphosate resistance evolution. The model is especially sensitive to the initial frequency of R alleles, and other genetic and reproductive parameters, including weed breeding system, dominance of the resistance trait and relative fitness, influence rates of resistance. CONCLUSION: Changing patterns of glyphosate use associated with glyphosate-resistant crops are increasing risks of evolved glyphosate resistance. Strategies to mitigate these risks can be explored with simulation models. Models can also be used to identify weed species that are most at risk of evolving glyphosate resistance.     

Simulating evolution of glyphosate resistance in Lolium rigidum I: population biology of a rare resistance trait

Despite frequent use for the past 25 years, resistance to glyphosate has evolved in few weed biotypes. The propensity for evolution of resistance is not the same for all herbicides, and glyphosate has a relatively low resistance risk. The reasons for these differences are not entirely understood. A previously published two‐herbicide resistance model has been modified to explore biological and management factors that account for observed rates of evolution of glyphosate resistance. Resistance to a post‐emergence herbicide was predicted to evolve more rapidly than it did to glyphosate, even when both were applied every year and had the same control efficacy. Glyphosate is applied earlier in the growing season when fewer weeds have emerged and hence exerts less selection pressure on populations. The evolution of glyphosate resistance was predicted to arise more rapidly when glyphosate applications were later in the growing season. In simulations that assumed resistance to the post‐emergence herbicide did not evolve, the evolution of glyphosate resistance was less rapid, because post‐emergence herbicides were effectively controlling rare glyphosate‐resistant individuals. On their own, these management‐related factors could not entirely account for rates of evolution of resistance to glyphosate observed in the field. In subsequent analyses, population genetic parameter values (initial allele frequency, dominance and fitness) were selected on the basis of empirical data from a glyphosate‐resistant Lolium rigidum population. Predicted rates of evolution of resistance were similar to those observed in the field. Together, the timing of glyphosate applications, the rarity of glyphosate‐resistant mutants, the incomplete dominance of glyphosate‐resistant alleles and pleiotropic fitness costs associated with glyphosate resistance, all contribute to its relatively slow evolution in the field.     

Influence of weed management measures on glyphosate resistance and endophyte infection in naturalized Italian ryegrass (Lolium multiflorum)

Recently, glyphosate‐resistant Italian ryegrass (Lolium multiflorum Lam.) was found on rice paddy levees in a western region of Shizuoka Prefecture, Japan. Naturalized populations of Italian ryegrass are frequently infected with fungal Epichloë endophytes. Endophytes often confer benefits to their host grasses. This study investigated the influence of five weed management treatments on glyphosate resistance and endophyte infection in Italian ryegrass that was growing on paddy levees where glyphosate‐resistant individuals were dominant. The weed management treatments were: (i) mowing once before the grass flowered; (ii) mowing once during flowering; (iii) mowing twice during flowering; (iv) glyphosate application before flowering; and (v) no treatment. The seeds were collected from the treatment plots in 2013 and 2014. The seeds were examined for endophyte infection and the seedlings that had been grown from the seeds were tested for the frequency of glyphosate resistance. The seedlings that had been derived from the glyphosate treatment showed higher frequencies of glyphosate resistance than those seedlings that had been derived from all the other treatments. Endophytes were found in all populations of the seeds from the paddy levees, with higher infection rates in the seeds that had been derived from the glyphosate treatment and the twice‐mowed treatment. There was a significant relationship between the endophyte infection frequency in the seeds and glyphosate resistance in the seedlings that had been grown from the same populations. The results indicate that where glyphosate herbicides are frequently used, selection for glyphosate‐resistant Italian ryegrass occurs, and along with this, the frequency of endophyte infection also increases.     

Glyphosate-resistant weeds of South American cropping systems: an overview

Herbicide resistance is an evolutionary event resulting from intense herbicide selection over genetically diverse weed populations. In South America, orchard, cereal and legume cropping systems show a strong dependence on glyphosate to control weeds. The goal of this report is to review the current knowledge on cases of evolved glyphosate-resistant weeds in South American agriculture. The first reports of glyphosate resistance include populations of highly diverse taxa (Lolium multiflorum Lam., Conyza bonariensis L., C. canadensis L.). In all instances, resistance evolution followed intense glyphosate use in fruit fields of Chile and Brazil. In fruit orchards from Colombia, Parthenium hysterophorus L. has shown the ability to withstand high glyphosate rates. The recent appearance of glyphosate-resistant Sorghum halepense L. and Euphorbia heterophylla L. in glyphosate-resistant soybean fields of Argentina and Brazil, respectively, is of major concern. The evolution of glyphosate resistance has clearly taken place in those agroecosystems where glyphosate exerts a strong and continuous selection pressure on weeds. The massive adoption of no-till practices together with the utilization of glyphosate-resistant soybean crops are factors encouraging increase in glyphosate use. This phenomenon has been more evident in Argentina and Brazil. The exclusive reliance on glyphosate as the main tool for weed management results in agroecosystems biologically more prone to glyphosate resistance evolution.     

Rapid vacuolar sequestration: the horseweed glyphosate resistance mechanism

BACKGROUND: Glyphosate‐resistant (GR) weed species are now found with increasing frequency and threaten the critically important GR weed management system. RESULTS: The reported ³¹P NMR experiments on glyphosate‐sensitive (S) and glyphosate‐resistant (R) horseweed, Conyza canadensis (L.) Cronq., show significantly more accumulation of glyphosate within the R biotype vacuole. CONCLUSIONS: Selective sequestration of glyphosate into the vacuole confers the observed horseweed resistance to glyphosate. This observation represents the first clear evidence for the glyphosate resistance mechanism in C. canadensis. Copyright © 2010 Society of Chemical Industry     

耐草甘膦菜豆耐性机理的初步研究

采用液谱测定耐性、感性菜豆叶片对草甘膦的吸收及草甘膦传导入根中的量。耐性、感性菜豆吸收、传导草甘膦无差异。耐性、感性菜豆 EPSP合成酶提取物中的蛋白质含量分别为 3.0 0 mg/ m L和 3.0 8mg/ m L ,EPSP合成酶的比活性分别为 2 .13nmol· min-1· mg-1蛋白和 1.97nmol· min-1· mg-1蛋白 ,但耐性、感性菜豆 EPSP合成酶比活性被草甘膦不同浓度抑制的差异大 ,抑制耐性菜豆 EPSP合成酶活性的草甘膦浓度 I50 为 19.2μmol/ L ,而感性的 I50 为 6 .3μmol/ L。两种菜豆对草甘膦的耐性差异在于各自的 EPSP合成酶比活性被草甘膦的抑制程度不同。     

Mobility and leaching of glyphosate: a review

There is currently concern that glyphosate, a strongly sorbing non-selective herbicide which is widely used in Europe, may be leached from the root zone into drainage water and groundwater. The purpose of this review is to present and discuss the state of knowledge with respect to the mobility and leaching of glyphosate from agricultural soils. Specific attention is given to the adsorption behaviour of glyphosate and the analysis of available studies on glyphosate transport. In addition, there are a number of experimental and numerical studies indicating that other strongly sorbing substances may be transported rapidly to the sub-surface. The experimental studies analysed in the paper encompass column-, lysimeter- and field-scale experiments on glyphosate transport. The experimental findings, combined with transport studies on other strongly sorbing pesticides in the literature, support the hypothesis that transport of glyphosate may be caused by an interaction of high rainfall events shortly after application on wet soils showing the presence of preferential flow paths. Concentrations of glyphosate in European groundwater have been reported occasionally but monitoring is still limited.     

Fate of glyphosate in soil and the possibility of leaching to ground and surface waters: a review

The very wide use of glyphosate to control weeds in agricultural, silvicultural and urban areas throughout the world requires that special attention be paid to its possible transport from terrestrial to aquatic environments. The aim of this review is to present and discuss the state of knowledge on sorption, degradation and leachability of glyphosate in soils. Difficulties of drawing clear and unambiguous conclusions because of strong soil dependency and limited conclusive investigations are pointed out. Nevertheless, the risk of ground and surface water pollution by glyphosate seems limited because of sorption onto variable-charge soil minerals, e.g. aluminium and iron oxides, and because of microbial degradation. Although sorption and degradation are affected by many factors that might be expected to affect glyphosate mobility in soils, glyphosate leaching seems mainly determined by soil structure and rainfall. Limited leaching has been observed in non-structured sandy soils, while subsurface leaching to drainage systems was observed in a structured soil with preferential flow in macropores, but only when high rainfall followed glyphosate application. Glyphosate in drainage water runs into surface waters but not necessarily to groundwater because it may be sorbed and degraded in deeper soil layers before reaching the groundwater. Although the transport of glyphosate from land to water environments seems very limited, knowledge about subsurface leaching and surface runoff of glyphosate as well as the importance of this transport as related to ground and surface water quality is scarce.