手性酰胺类杀菌剂研究进展

手性农药在生物体和环境中表现出环境行为、生物活性等方面的差异,采用传统的评价方式不能全面的评估手性农药对环境乃至人类的风险大小。酰胺类杀菌剂对由担子菌及立枯丝核菌等引起的植物病害具有良好的防治效果,然而部分含有手性中心原子的酰胺类杀菌剂会因为对映体表现出的差异,影响其安全性评价的准确性。为了全面开展手性酰胺类杀菌剂的立体选择性研究,本文归纳了手性酰胺类杀菌剂在对映体分离方法、选择性环境行为、选择性毒性与生物活性等方面的研究进展,对其科学使用具有指导性意义。     

环境因子对脱氧雪腐镰刀菌烯醇在小麦中残留降解的影响（英文）

利用三重四级杆液质联用仪LCMSMS研究了环境因子对小麦籽粒中DON毒素的降解影响,不同处理得到的DON毒素降解半衰期范围在54.57~71.44 d,150 d后降解率为78.85%~87.00%,对毒素的降解有加快作用的是自然光强光(10 000 lx)黑暗,90%湿度50%湿度,而高温并不能加快毒素的降解。     

含OH11发酵液玉米种衣剂的研制及其对茎基腐病的效果评价

通过正交试验,筛选分散剂、乳化剂及增稠剂,利用湿法砂磨法,将OH11发酵液研制成30%悬浮种衣剂,将研制的玉米种衣剂不同药种比包衣后测定对玉米根长、苗长、鲜重指标影响,并通过菌土混合法,测定了药剂对玉米茎基腐防效。结果显示,30% OH11发酵液悬浮种衣剂最佳配方为OH11发酵液30%、木钠0.8%、PEG4000 3%、XG0.2%、红染4%、成膜剂3%,水余量。该种衣剂药种比1:200、1:500包衣对玉米生长发育影响不大,1:200时对玉米茎基腐（腐霉菌）防效达93.55%,1:500防效达80.51%,显著高于对照药剂30%戊唑醇悬浮种衣剂（39.16%）。结果显示30% OH11发酵液悬浮种衣剂能够很好的应用于玉米茎基腐（腐霉菌）病的防治。     

新奥霉素母药对5种非靶标生物的急性毒性

测定了新奥霉素 (xinaomycin)母药对5种非靶标生物——斑马鱼Brachydanio rerio、大型溞Daphnia magna Straus、羊角月芽藻Pseudokirchneriella subcapitata、意大利工蜂Apis mellifera L.和家蚕Bombyx mori的急性毒性。结果显示:新奥霉素母药对斑马鱼96 h-LC₅₀值大于100 mg/L;对大型溞48 h-EC₅₀值为1.48 mg/L;对羊角月芽藻72 h-EyC₅₀值为8.74 mg/L,72 h-ErC₅₀值为29.2 mg/L;对意大利工蜂急性经口96 h-LD₅₀值为31.3 μg/蜂,急性接触96 h-LD₅₀值为39.9 μg/蜂;对家蚕96 h-LC₅₀值大于2.00×103 mg/L。研究表明,新奥霉素母药对斑马鱼、羊角月芽藻、蜜蜂、家蚕均为低毒,对大型溞是中等毒性。     

Sensitivity of Rhizoctonia solani causing rice sheath blight to fluxapyroxad in China

Fluxapyroxad,3-(difluoromethyl)-1-methyl-N-(3’,4’,5’-trifluorobiphenyl-2-yl) pyrazole-4-carboxamide (C₁₈H₁₂F₅N₃O, Fig. 1), is a SDHI fungicide, which is a new active ingredient that interferes with succinate ubiquinone reductase in the electron transport chain of fungi. Between 2008 and 2010, a total of 128 isolates of Rhizoctonia solani from Anhui Province of China were characterized for the baseline sensitivity to fluxapyroxad. The isolates collected between 2008 and 2010 all showed similar sensitivity to fluxapyroxad. Baseline sensitivity was distributed as unimodal curves with an average EC₅₀ value of 0.054?±?0.014 μg ml^?1. However, EC₅₀ values of boscalid for inhibition of mycelial growth of R. solani isolates ranged from 1.89 to 2.68 μg/ml and the average (±SE) EC₅₀ value was 2.212?±?0.228 μg/ml, indicating that the R. solani isolates were less sensitive to boscalid than that of fluxapyroxad. Fluxapyroxad exhibited excellent protective and curative activity against rice sheath blight and provided 82.6–94.2 % protective or curative control efficacy. In field trials, control efficacy of fluxapyroxad at 100 g a.i/ha 15 days and 30 day after second application was 83.4–88.0 %, suggesting excellent activity against sheath blight. Control efficacy of boscalid at a dosage of 600 g a.i/ha 15 days and 30 day after second application was about 51.7–57.0 %. There was a significant difference in the efficacy between fluxapyroxad and boscalid or jinggangmycin. These results suggested that fluxapyroxad is a good alternative fungicide to jinggangmycin for the control of rice sheath blight.     

氟唑菌苯胺对蛋白核小球藻的立体选择性毒性效应

为了探究氟唑菌苯胺对水生生物的立体选择性毒性效应,测定了氟唑菌苯胺对映体对蛋白核小球藻的急性毒性以及光合色素含量的影响。结果表明,S-氟唑菌苯胺对蛋白核小球藻具有更高的急性毒性,是R-氟唑菌苯胺1.2倍。高剂量暴露浓度下,S-氟唑菌苯胺对小球藻叶绿素a、叶绿素b、类胡萝卜素生物合成的抑制率分别为35%、28%、37%,是R-对映体的2.1、1.9、2.8倍,表明氟唑菌苯胺对蛋白核小球藻的立体选择性急性毒性可能是由于对映体对光合色素生物合成抑制差异造成的。降解实验结果表明低毒对映体R-氟唑菌苯胺被优先降解,第7天时R-氟唑菌苯胺和S-氟唑菌苯胺降解率分别为82.5%和65.8%,EF值为0.12,且对映体构型稳定。研究结果为氟唑菌苯胺水生生态风险评价提供数据支撑,同时为手性农药立体选择性机制研究提供新的思路。     

甘肃酒泉发现坎诺单孢菌引起的甜瓜倒秧

2018年7月中旬在甘肃省酒泉市金塔县, 甜瓜成熟前10~20 d, 一些田块出现了严重的倒秧, 从罹病植株的褐腐根上分离到坎诺单孢菌Monosporascus cannonballus, 病株分出率达76.9%。致病性测定结果显示:在试验条件下(25℃±3℃), 菌株TG-84对甜瓜(品种:‘86-1’)的致病性强, 出苗后13 d, 倒苗率达80%。     

基于Wolff-Kishner-黄鸣龙法合成红火蚁告警信息素及其触角电位反应

告警信息素是红火蚁(Solenopsis invicta Buren)中一类重要的信息素物质,具有引诱、趋避和聚集等多种活性,能够引起红火蚁强烈的行为反应。 本研究通过Wolff-kishner-黄鸣龙还原法一步合成红火蚁告警信息素,并经气相色谱-质谱(GC-MS)和标准品对其结构进行鉴定和分析。结果表明,化合物纯度达到90.2%;该合成方法合理、简便和高效,反应条件可控,无安全隐患,适合工业化生产和应用。触角电位(EAG)实验表明,合成告警信息素能够引起红火蚁工蚁强烈的行为反应,并在100 μg剂量下EAG反应显著高于标准品(P<0.05)。     

白背飞虱在玉米上的取食行为和发育繁殖特征

为探究玉米能否作为白背飞虱Sogatella furcifera的过渡寄主,采用刺吸电位图谱技术对白背飞虱在玉米上的取食行为进行监测,并测定其取食玉米后的营养物质和繁殖力变化。结果显示,不同生育期玉米处理组中,N4-a波和N4-b波的总时间分别超过37.88 min和87.15 min,平均持续时间分别超过5.26 min和28.78 min;不同生育期玉米被取食部位的可溶性糖和游离氨基酸含量均显著降低,而在成虫虫体中这2种营养物质的含量均显著升高;2龄若虫与成虫的N4-a波和N4-b波的总时间分别为78.04、62.16 min和248.14、299.72 min,均无显著差异;取食玉米的白背飞虱产卵期和单雌产卵量分别为4.45 d和13.83粒,显著少于取食水稻组的10.90 d和162.12粒,且在玉米上孵化的若虫在3龄前全部死亡。表明白背飞虱成虫和若虫虽能在不同生育期玉米上进行有效取食,但无法完成继代繁殖,玉米只能作为白背飞虱的临时性过渡寄主。     

Characterization and Proteomic Analysis of Novel Rice Lesion Mimic Mutant with Enhanced Disease Resistance

Lesion mimic mutants(LMMs) are plants that spontaneously form lesions without pathogen infection or external stimulus and exhibit resistance to pathogens. Here, a rice LMM was created by ethyl methane sulfonate mutagenesis, named as hpil(hydrogen peroxide induced lesion). Diaminobenzidine and trypan blue staining showed that large amounts of H_2O_2 were produced and cell death was occurred at and around the parts of lesion mimic in the rice leaves. The phenotype of hpil is controlled by a single recessive gene, localized at a 2 Mb interval on chromosome 2. The data suggested that hpil is a novel LMM with enhanced bacterial and fungal disease resistance, and multiple pathogenesis-related proteins(PRs) were up-regulated. The proteomes of leaves at three positions(different degrees of lesion mimic severity) were characterized in hpil compared with its wild type plant. Differentially expressed proteins were detected by two dimensional difference gel electrophoresis and 274 proteins were identified by MALDI TOF/TOF~(TM). These proteins were related to metabolic process, cellular process and response to stimulus, with mostly down-regulated in hpil leaves. Many of these proteins were related to the Calvin cycle, photosynthetic electron transport chain, glycolysis/gluconeogenesis and phosphonates pathways. Some resistance-related proteins including 14-3-3 proteins, OsPR10 and antioxidases such as peroxidase, superoxide dismutase and ascorbate peroxidase were up-regulated in leaves with lesion mimic. These results provide the foundation for cloning of the target gene and shed light on the mechanism involved in autoimmunity of rice.