A mutation confers Monochoria vaginalis resistance to sulfonylureas that target acetolactate synthase

Acetolactate synthase (ALS) is the target enzyme for four distinct families of compounds: sulfonylureas (SUs), imidazolinones, triazolopyrimidine sulfonanilides, and pyrimidinyl oxybenzoates. We cloned and sequenced the fragments encoding ALS genes from biotypes of Monochoria vaginalis susceptible (S) and resistant (R) to SU-herbicides. The nucleotide sequences of the 39 bp Domain A region for R M. vaginalis biotype differed from that of the S biotype by a single nucleotide substitution at variable Pro codon of Domain A (CCT to TCT), predicting a Pro in the S but a Ser in the R biotype. No nucleotide differences between S and R M. vaginalis were observed in Domain D. We suggest that the amino acid substitution at Domain A region is responsible for resistance to SU-herbicides in M. vaginalis collected from Ushiku City, Ibaraki Prefecture, Japan.     

磺酰脲类除草剂的应用及检测方法

磺酰脲类除草剂是上世纪80年代美国杜邦公司研发出来的一种除草剂,其具有高效、广谱、低毒、高选择性等优点,因此,一经问世就得到了广泛应用。但是,由其引起的土壤、地下水污染问题而饱受诟病。有些磺酰脲除草剂难以降解,可对环境造成持续的污染,更有甚者,农作物也会因此而造成农残超标。因此,磺酰脲类除草剂在环境、农产品中的残留问题及和检测技术研究进展值得我们关注。     

不同小麦品种对苯磺隆除草剂的耐药性研究

通过敏感性测定,明确了不同小麦品种对麦田磺酰脲类除草剂苯磺隆的耐药性。结果表明:河东TX耐药性较强;晋麦67、晋农66、晋麦47、长5456、农大3608耐药性居中;长006219、乐39耐药性较弱。长006219对苯磺隆药剂的敏感性最强,用药不当,易产生药害。对品种耐药性以及药剂抑制力的进行了综合分析。     

甲磺隆的应用技术及对后茬作物的安全性研究

在冬小麦 1～ 2叶期施用甲磺隆 1.8～ 2.5 g/hm2 ,可有效防除北京地区麦田常见阔叶杂草 ,优于当前常用除草剂苯磺隆 15g/hm2 春季施用的除草效果 ,安全性与春季施用苯磺隆 15g/hm2 相当。实验室降解结果表明 ,当甲磺隆初始浓度为 6.25μg/kg以下时 ,经过215d后 ,对后茬玉米安全。研究表明 ,向日葵是甲磺隆理想的生物测定试材 ,对甲磺隆的最低检出浓度达到 0.125μg/kg,其根长抑制率与除草剂浓度有高度的相关性 ,最佳的剂量 -反应模型为 y=a+b lnx     

Weed control with selected herbicides in acetolactate synthase-resistant sorghum

The recent development of grain sorghum hybrids with resistance to acetolactate synthase (ALS)-inhibiting herbicides has allowed for the use of several post-emergence applied (POST) ALS-inhibitors to control weeds in the crop. Field experiments were conducted at four sites in Kansas in 2008 to evaluate the efficacy of nicosulfuron and nicosulfuron + rimsulfuron applied alone or in combination with dicamba, metsulfuron methyl, and atrazine. All POST treatments slightly injured sorghum 2 weeks after treatment (WAT) at Garden City and Hesston, whereas at Hays and Manhattan, only treatments that included dicamba caused injury. Nicosulfuron + rimsulfuron applied alone provided 41, 83, 74, and 93% control of grasses 4 WAT at Garden City, Hays, Hesston, and Manhattan, respectively. However, to obtain the highest level broadleaf weed control, nicosulfuron or nicosulfuron + rimsulfuron need to be applied with other broadleaf herbicides. POST treatment of nicosulfuron + metsulfuron methyl + dicamba + atrazine provided 90% or greater control of all broadleaf weeds at sorghum flowering. Sorghum grain yield was greater following all herbicide treatments compared with the weedy check. The POST treatment that provided the highest yield at Garden City was nicosulfuron + rimsulfuron + atrazine, whereas in Hesston and Manhattan, nicosulfuron + metsulfuron methyl + dicamba + atrazine provided the highest yields. This research showed that many grasses can be effectively controlled with POST applications of nicosulfuron or nicosulfuron + rimsulfuron in ALS-resistant sorghum. The research also indicated that broadleaf weed control is greater when nicosulfuron or nicosulfuron + rimsulfuron are applied with other broadleaf-control herbicides such as dicamba, metsulfuron methyl, and atrazine.     

玉米对磺酰脲类除草剂敏感性及土壤残留的研究

采用室内模拟添加法、盆栽法和土壤残留动态试验法,分别研究了不同玉米品种对磺酰脲类除草剂的敏感性、磺酰脲类除草剂对敏感玉米品种苗期影响和磺酰脲类除草剂在土壤中的残留期。结果表明:供试玉米品种对磺酰脲类除草剂存在不同程度的敏感性差异,该类除草剂ED50以上浓度对玉米苗期的根长、株高、叶面积有明显的影响。同时,3种磺酰脲类除草剂苯磺隆、噻磺隆和苄嘧磺隆在土壤中的残留期分别为69、79和150d,并且存在着一定的差异。     

Sulfonylurea-resistant biotypes of Monochoria vaginalis generate higher ultraweak photon emissions than the susceptible ones

All living organisms spontaneously generate ultraweak photon emissions, which originate from biochemical reactions in cells. Current research uses the ultraweak photon emission from organisms as a novel indicator in nondestructive analyses of an organisms living state. This study indicates that ultraweak photon emissions from Monochoria vaginalis are different between resistant biotypes (R) to sulfonylurea (SU) and susceptible biotypes (S). In SU-R biotypes, distinct increases in photon emissions were observed, but there was little increase in SU-S biotypes. In addition, photon emissions from the resistant biotypes of M. vaginalis were suppressed by treatment with P450 inhibitors. This suggests that cytochrome P450 monooxygenase, which plays a crucial role in the metabolic detoxification of SUs, could be associated with the generation of ultraweak photon emissions. Ultraweak photon emissions have a potential use in a novel diagnosis system as an indicator in a nondestructive testing of weeds resistant to SUs.     

小麦中多种磺酰脲类除草剂的UPLC-MS/MS分析方法研究

[目的]用超高效液相色谱-串联四极杆质谱(UPLC-MS/MS),在多反应监测(MRM)模式下,建立小麦中11种磺酰脲类除草剂残留的定性定量分析方法。[方法]样品经乙腈提取,乙腈饱和的正己烷液-液分配,用弗罗里硅土小柱净化,采用UPLC-MS/MS(ESI+)测定。[结果]在2～200μg/L浓度范围内方法中各种磺酰脲类除草剂线性良好,相关系数在0.999 8和0.999 9之间。在5,25和50μg/kg 3个添加浓度水平下的平均回收率在76.2%和102.4%之间,相对标准偏差不大于10%。[结论]该方法快速简便,可满足小麦中多种磺酰脲类除草剂的检测要求。     

土壤中磺酰脲除草剂降解机制研究进展

磺酰脲除草剂是一种高效、低毒、低用量(10～40g/hm~2)的新型除草剂,广泛应用于水稻、小麦和玉米等田间杂草的控制,在土壤中降解途径主要为水溶性光分解、醇解、化学水解和微生物分解,且4种降解途径下各自产生不同的降解产物。对土壤中磺酰脲除草剂降解产物的测定多采用气相色谱、液相色谱、酶连免疫吸附和生物检测,各测定方法均有利弊,色谱法需繁琐的纯化程序提纯样品以达到检测极限0.1μg/kg,生物检测和免疫吸附法测定快速、灵敏度高但缺乏专一性。结合生物降解模型研究,阐述了磺酰脲除草剂的降解机制。     

化学杂交剂EXP对油菜的杀雄效果

化学杂交剂EXP的主要成分是一种磺酰脲类化合物,作用靶标是植物的乙酰乳酸合成酶（acetolactate synthase,ALS）,通过抑制酶活性,阻止支链氨基酸缬氨酸、亮氨酸和异亮氨酸的合成。在甘蓝型油菜自交系82089抽薹15～20 cm高,最大花蕾长度1～2 mm时期,单株用药量12～15 mL,用0.05 μg/mL、0.25 μg/mL EXP溶液处理可分别诱发92%和97%不育率。而0.25 μg/mL浓度处理不育株的育性较为稳定,自交结实率为6.6%,可以作为最佳用药浓度的参考值。EXP透导的不育株叶色变浅、株高降低、花蕾密集、花期推迟、花瓣褪色、花药干瘪无花粉。检测结果表明,不育株花蕾叶绿素和类胡萝卜素含量有所减少,处理雄蕊的过氧化物酶和酯酶活性降低,而水溶性蛋白质含量显著减少。同一时期用EXP处理芥菜型油菜和白菜型油菜也可诱导雄性不育,但芥菜型油菜不育持续时段较短,白菜型油菜结实性不好,不宜用于生产杂交种。本研究结果的意义在于,磺酰脲类ALS抑制剂种类非常多,有可能从中筛选到更高效、更持久的化学杂交剂。