吡唑解草酯对小麦细胞色素P450的诱导作用及其光谱特征

用吡唑解草酯浇灌小麦,试验结果表明,50μmol/L吡唑解草酯处理抗6号小麦,可使其细胞色素P450含量达到最大值108.18 pmol/mg蛋白质,为对照组的1.67倍;100μmol/L吡唑解草酯处理敏18号小麦,可使其细胞色素P450含量达到最大值80.97 pmol/mg蛋白质,为对照组的1.86倍。吡唑解草酯对两个小麦品种的细胞色素P450均有诱导作用,抗6号小麦更容易被诱导,这与两小麦品种的耐药性一致。室温(20±1)℃下扫描不同时间的细胞色素P450-CO结合光谱,结果表明,微粒体粗提液室温(20±1)℃保存200 min后,细胞色素P450完全转变为细胞色素P420。     

不同小麦品种对双氟磺草胺的耐药性差异及机理

室内采用平皿法和酶活力测定法探讨了不同小麦品种对双氟磺草胺的耐药性差异及其机理。结果表明,不同小麦品种根对双氟磺草胺的耐药性差异较大,其中济宁13对该药剂最为敏感,IC50值仅为0.221 2 μg/mL,烟农15、枣20-28、济南17与之相当(耐药性倍数为1.09~1.99),泰山9818、山农6号和潍麦8号耐药性较强(耐药性倍数为10.33~13.92)。酶活力测定结果表明:虽然耐药型品种潍麦8号和敏感型品种济南17对双氟磺草胺的耐药性差异显著,但其靶标酶乙酰乳酸合成酶(ALS)在离体条件下对该药剂的敏感性却无显著差异;在活体条件下,二者ALS活力均可很快恢复,其中潍麦8号恢复较快。经双氟磺草胺处理后,与济南17相比,潍麦8号的代谢酶谷胱甘肽- S -转移酶(GSTs)相对活力变化幅度较大且反应时间较短,在第2 d即可达到峰值1.460,而济南17在第3 d才达到峰值1.398。研究表明,不同小麦品种对双氟磺草胺的耐药性存在差异 的原因之一可能是由于GSTs对双氟磺草胺的代谢差异,而与靶标酶ALS对药剂的敏感程度无关。     

水稻不同品种或组合对甲磺隆耐药性差异的机制研究

以水稻乙酰乳酸合成酶(ALS)比活力为研究对象,通过在离体和活体条件下比较其对甲磺隆的敏感性水平,探讨了水稻不同品种或组合的耐药性差异机制。结果表明,离体条件下不同水稻品种或组合ALS对甲磺隆均较敏感,当甲磺隆浓度为100 μg/L时,对ALS比活力抑制率达60%以上,且活力百分比与甲磺隆浓度对数成直线负相关关系,相关程度显著或极显著;活体条件下ALS活力均受到甲磺隆不同程度的抑制,但同一品种ALS活力不随甲磺隆浓度的变化而呈现规律性变化。在甲磺隆浓度相同时,活体条件下所有供试水稻品种ALS活力均显著高于离体条件下的ALS活力,影响程度与植株耐药性差异基本一致,说明甲磺隆在水稻体内存在较强代谢失活作用,代谢失活差异是水稻不同品种或组合对甲磺隆的耐药性差异机制。     

不同小麦品种对苯磺隆耐药性差异及其机理

室内用砂培法测定11种小麦品种对苯磺隆的相对敏感性,其敏感性有较大差异.碧玛4号、维麦8号对苯磺隆有很强的耐药性,IC50可分别达到502.6和409.3aiμg/kg,济1 3号为156.9aiμg/kg,鲁麦22号、黄县大粒对苯磺隆较为敏感,IC50低于45.0 aiμg/kg.以上5种小麦离体ALS对苯磺隆的敏感性没有明显差异,敏感品种黄县大粒IC50为154.2nmol/L,甚至较维麦8号149.3nmol/L略高.ALS活体试验表明,小麦可以很快恢复苯磺隆对ALS活性的抑制,且耐药型品种恢复能力较强,碧玛4号、维麦8号ALS恢复活性只需1.5天,敏感品种需3天.碧玛4号、维麦8号除草剂解毒酶系GSTs相对于敏感品种对苯磺隆有较大的反应幅度和较短的反应时间,第2天就分别达到1.46、1.42的峰值,而济13号、鲁麦22号、黄县大粒变化幅度较小,第3天才达到峰值,活性分别为1.39、1.33和1.32.研究表明,小麦各品种对苯磺隆的耐药能力产生差异的主要原因之一是小麦GSTs对苯磺隆的代谢所致,而与小麦ALS对苯磺隆的敏感程度无关.     

不同玉米品种对氯吡嘧磺隆的耐药性差异及其机制

为科学评价氯吡嘧磺隆对玉米的安全性,采用室内盆栽法和酶活力测定法探讨不同玉米品种对氯吡嘧磺隆的耐药性差异及其机制。不同玉米品种对氯吡嘧磺隆的耐药性有较大差异,其中甜玉米耐药性最差,IC10仅为94.87g/hm2(有效成分,余同)。花糯1号、鲁单981、五岳97-1等品种表现出中等耐药性,耐药性倍数为1.51～1.97;五岳21、郑单958、强盛16等耐药性较强,耐药性倍数为2.05～2.43。强盛16、鲁单981和甜玉米对氯吡嘧磺隆的耐药性差异显著,但其靶标酶乙酰乳酸合成酶(ALS)在离体条件下对该药剂的敏感性差异不显著;在活体条件下,三者ALS活力均可很快恢复,且耐药性品种恢复能力较强。与甜玉米相比,经氯吡嘧磺隆处理后强盛16的谷胱甘肽-S-转移酶(GSTs)对氯吡嘧磺隆的反应幅度较大和反应时间较短,第72h相对活力就达到4.2的峰值,而甜玉米变化幅度相对较小,第96 h才达到2.6的峰值。研究表明,不同玉米品种对氯吡嘧磺隆耐药性的差异源于GSTs对氯吡嘧磺隆的代谢差异,而与靶标酶ALS对氯吡嘧磺隆的敏感程度无关。     

小麦田禾本科杂草适用除草剂及其使用技术

目前江苏省小麦生产上用于防除禾本科杂草的除草剂品种主要有7种:异丙隆、精(噁)唑禾草灵、甲基二磺隆、炔草酯、唑啉草酯、氟唑磺隆、啶草胺.本文介绍了这7种除草剂的除草特性和使用方法.     

双氟磺草胺的除草活性及对不同小麦品种的安全性评价

双氟磺草胺为三唑并嘧啶磺酰胺类除草剂,为了明确其在我国北方麦田的应用前景,采用室内生测法研究双氟磺草胺的杀草谱、除草活性及对不同小麦品种安全性。双氟磺草胺对麦田常见阔叶杂草活性较高,对麦田恶性杂草播娘蒿、麦瓶草、麦家公、猪殃殃和荠菜的除草活性均高于常用除草剂苯磺隆,毒力倍数分别为1.56、6.26、1.65、18.27和22.75。济南17和山优2号2种小麦对双氟磺草胺的耐药性分别为苯磺隆的2.57倍和11.66倍。双氟磺草胺在小麦与5种杂草之间的选择性指数(11.16～49.32)远优于苯磺隆。该除草剂对小麦苗期的株高及鲜重有抑制作用,且对不同小麦品种的影响差异显著,其中对临麦2号、济宁13及济南17的株高和鲜重抑制率相对较高,对潍麦8号、山农6号及泰山9818等相对较低。研究表明双氟磺草胺具有很好的应用前景。     

麦田抗性生物型猪殃殃对苯磺隆的抗性机制

为探讨猪殃殃Galium aparine抗药性生物型(R)对苯磺隆的抗性机制,测定了苯磺隆对猪殃殃抗性、敏感(S)生物型体内靶标酶 、代谢酶 及抗氧化酶 影响的差异。离体试验结果表明,苯磺隆对R、S生物型猪殃殃ALS的抑制中量(IC50)分别为0.682、0.718 μg/L(有效剂量),R、S生物型猪殃殃ALS对苯磺隆的敏感性不存在差异。活体试验结果表明,苯磺隆茎叶喷雾处理后,R、S生物型ALS活力均表现为先上升,但S生物型上升幅度小,且随后快速下降,第3 d即回落至对照之下,并维持在低于对照的水平,而R生物型ALS活力在第2 d可达对照的4.10倍,第5 d 基本回落至对照水平,之后基本维持在对照水平;R生物型GSTs活力在第1 d即开始上升,最高可达对照的 2.40 倍,而S生物型则表现为先下降,然后小幅回升,最高为对照的1.61倍,两者在10 d左右均回落至对照水平;R生物型SOD活力与对照基本相同,而S生物型虽略有下降,但R、S间不存在显著差异;两者POD活力虽均有大幅提高,但亦不存在显著差异。结果表明,低水平抗药性生物型猪殃殃对苯磺隆产生抗性的原因可能是ALS过量表达及GSTs对苯磺隆的代谢作用加强,而不是由于ALS的敏感性下降,同时POD、SOD在减轻药害中也具有一定作用。     

4种除草剂防除保护性耕作麦田早熟禾效果及其对作物的安全性

通过田间试验,比较4种除草剂药后不同时期对保护性耕作麦田早熟禾的防效及其增产效果,进而比较7．5％啶磺草胺WG、3．6％甲基二磺隆·甲基碘磺隆钠盐WG、15％炔草酸WP、6．9％精唑禾草灵EW 4种除草剂防除早熟禾效果和对小麦的安全性。采用田间药效试验方法,对麦田早熟禾采用喷雾处理,进行4种除草剂防除麦田早熟禾效果及其对作物的安全性试验。7．5％啶磺草胺WG 187．50 g/hm2和3．6％甲基二磺隆·甲基碘磺隆钠盐WG 450．00 g/hm2对早熟禾鲜质量防效分别为83．58％、84．87％。3．6％甲基二磺隆·甲基碘磺隆钠盐WG对春小麦通麦1号品种有一定的药害,药害程度：甲基二磺隆·甲基碘磺隆钠盐＞啶磺草胺。6．9％精唑禾草灵EW、15％炔草酸WP对早熟禾达未到防治要求。187．50 g/hm27．5％啶磺草胺WG,安全性好、防效高、持续期长,可进一步示范推广使用。     

河南省多花黑麦草对ACCase和ALS抑制剂的抗性及其靶标基因突变分析

为明确河南省部分地区的多花黑麦草Lolium multiflorum种群对乙酰辅酶A羧化酶（acetylCoA carboxylase,ACCase）和乙酰乳酸合成酶（acetolactate synthase,ALS）抑制剂类除草剂的抗性水平和抗性机理,采用整株生物测定法测定采自新乡市和驻马店市的多花黑麦草种群对ACCase抑制剂类除草剂精噁唑禾草灵、炔草酯、唑啉草酯和ALS抑制剂类除草剂甲基二磺隆、氟唑磺隆、啶磺草胺的抗性水平,并对多花黑麦草ACCase和ALS靶标酶编码基因进行克隆及氨基酸序列比对,分析其靶标抗性机理。结果显示,与多花黑麦草敏感种群HNXX01相比,HNZMD04和HNXX05种群对6种除草剂均产生了抗性,HNZMD04种群对精噁唑禾草灵和啶磺草胺的相对抗性倍数分别为44.65和40.31,对炔草酯和氟唑磺隆的相对抗性倍数分别为11.91和11.93;HNXX05种群对精噁唑禾草灵和氟唑磺隆的相对抗性倍数分别为27.70和25.67。HNZMD04和HNXX05抗性种群的ACCase基因均发生了D2078G突变,2个种群的突变率分别为55%和70%;HNZMD04...     

Acetolactate synthase activity and chlorsulfuron sensitivity of wheat cultivars

Differences were observed in the sensitivity of three wheat (Triticum aestivum L.) cultivars to chlorsulfuron. Shoot dry weight was reduced by foliar applications of chlorsulfuron to a greater extent in cv. Rongotea than in cvs Lancer and Kotare. There was no difference between these cultivars in the specific activity of acetolactate synthase (ALS) enzyme extracted from leaves or roots. Moreover, chlorsulfuron inhibited ALS from the wheat cultivars to the same extent in?vitro. ALS measurement in vivo showed that after 15 h of incubating excised leaf tissues with chlorsulfuron, there was a greater reduction in ALS enzyme activity in Rongotea than in the other cultivars. Furthermore, 1 day after a foliar application of chlorsulfuron, in vitro ALS activity in leaves was reduced more in Rongotea than in Lancer or Kotare. Recovery of the enzyme activity following chlorsulfuron application was quicker in Kotare than in Lancer or Rongotea. It is concluded that differences in sensitivity of these wheat cultivars to chlorsulfuron are not due to differential ALS sensitivity or level, but may be due to differential rates of herbicide metabolism.     

绿磺隆、醚苯磺隆及其体外代谢物对乙酰乳酸合成酶的离体抑制作用

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。     

Corn poppy (Papaver rhoeas) cross-resistance to ALS-inhibiting herbicides

BACKGROUND: Papaver rhoeas (L.) has evolved resistance to tribenuron in winter wheat fields in northern Greece owing to multiple Pro₁₉₇ substitutions. Therefore, the cross‐resistance pattern to other sulfonylurea and non‐sulfonylurea ALS‐inhibiting herbicides of the tribenuron resistant (R) and susceptible (S) corn poppy populations was studied by using whole‐plant trials and in vitro ALS catalytic activity assays. RESULTS: The whole‐plant trials revealed that tribenuron R populations were also cross‐resistant to sulfonylureas mesosulfuron + iodosulfuron, chlorsulfuron and triasulfuron. The whole‐plant resistance factors (RFs) calculated for pyrithiobac, imazamox and florasulam ranged from 12.4 to > 88, from 1.5 to 28.3 and from 5.6 to 25.4, respectively, and were lower than the respective tribenuron RF values (137 to > 2400). The ALS activity assay showed higher resistance of the ALS enzyme to sulfonylurea herbicides (tribenuron > chlorsulfuron) and lower resistance to non‐sulfonylurea ALS‐inhibiting herbicides (pyrithiobac > florasulam ≈ imazamox). CONCLUSION: These findings indicate that Pro₁₉₇ substitution by Ala, Ser, Arg or Thr in corn poppy results in a less sensitive ALS enzyme to sulfonylurea herbicides than to other ALS‐inhibiting herbicides. The continued use of sulfonylurea herbicides led to cross‐resistance to all ALS‐inhibiting herbicides, making their use impossible in corn poppy resistance management programmes. Copyright © 2011 Society of Chemical Industry     

Characterisation and molecular basis of ALS inhibitor resistance in the grass weed Alopecurus myosuroides

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.     

Differences between spring wheat cultivars in tolerance to <Emphasis Type="Italic">Fusarium</Emphasis> seedling blight under organic field conditions

Use of Fusarium-infected seed for cereal crops results in a reduced plant density due to seedling blight. This is especially a problem in organic agriculture, for which currently no practical seed disinfection methods are available. In the present paper we investigated whether spring wheat cultivars differ in tolerance to seedling blight in vivo, whether the possible differences could be linked to cultivar differences in initial growth rates, and whether differences in weed infestation were related to differences in emergence. Seed six spring wheat cultivars (Melon, Lavett, SW Kungsjett, Epos, Pasteur, Thasos), containing three Fusarium infection levels were obtained and sown in two field experiments in 2006 and 2007 and in an outdoor pot experiment in 2007. Results indicated that the six spring wheat cultivars differed in their tolerance to seedling blight, and consequently in the percentage of emergence of their seeds. The relative levels of tolerance to seedling blight of the six cultivars were robust in the three experiments performed. No clear relationship between initial growth rates and tolerance was found. In our experiments, no early and homogenous weed pressure was present, but in the 2007 field experiment a relationship between initial seedling emergence and weed infestation after anthesis was determined. Based on the presented results we suggest that additional to resistance to Fusarium head blight (FHB), differences in tolerance to seedling blight should also be considered during selection of wheat cultivars for organic agriculture.     

Resistance levels and chemical control options of sterile oat (Avena sterilis L.) in Northern Greece

Abstract

Whole-plant response experiments in pots and field experiments over two years were conducted to study the resistance levels and chemical control options of sterile oat (Avena sterilis L.) in typical wheat production areas of northern Greece. Data revealed high levels of resistance to the ACCase-inhibiting herbicides clodinafop-propargyl and fenoxaprop-p-ethyl in all sterile oat populations, noticeable levels of resistance of some populations to tralkoxydim and pinoxaden, and high susceptibility of four out of the five populations to the prepackage mixture [mesosulfuron?+?iodosulfuron]. The addition of chlorpyrifos did not improve the efficacy of all herbicides against the resistant populations, implying target-site resistance in the populations tested rather than resistance due to P450-mediated enhanced herbicide metabolism. These results indicated that all populations were at least four times more resistant to clodinafop-propargyl, fenoxaprop-p-ethyl and diclofop-methyl than the susceptible populations, but noticeable levels of resistance of some sterile oat populations to tralkoxydim, pinoxaden and the prepackage mixture [mesosulfuron?+?iodosulfuron] were also recorded. However, viable options for chemical control of this weed still exist.     

麦田茼草春季化学防除技术研究

通过田间试验筛选春季有效防除麦田茼草的除草剂配方。结果表明,40％肟草酮水分散粒剂60g／667m2＋50％异丙隆可湿性粉剂100g／667m2、7．5％啶磺草胺水分散粒剂11g／667m2＋30g／L甲基二磺隆油悬剂12g／667m2、40％肟草酮水分散粒剂60g／667m2＋30g／L甲基二磺隆油悬剂20g／667m。处理均可用于春季小麦田蔺草的有效防除,且对小麦相对安全。