小菜蛾对杀螟丹抗药性的生化遗传研究

采用室内选育的小菜蛾对杀螟丹的抗性品系和敏感品系,研究了各杂交世代小菜蛾多功能氧化酶（ＭＦＯ）,乙酰胆碱酯酶（ＡｃｈＥ）和羧酸酯酶活性。结果表明：（１）抗性品系（抗性提高３５．５倍）多功能氧化酶环氧化活性比敏感品系高（１．８３倍）,并随着杂交后代中对杀螟丹抗性水平的下降而降低;（２）抗药性品系和敏感品系的ＡｃｈＥ和ＣａｒＥ活性没有明显差异。     

小菜蛾nAChR靶标敏感性与沙蚕毒素类药物的抗性关系

【目的】研究抗杀虫双、杀螟丹和溴氰菊酯品系的神经乙酰胆碱受体及与它们对沙蚕毒素类药物的抗性间的关系。【方法】测定不同品系小菜蛾的神经乙酰胆碱受体与125I标记的α-银环蛇毒素的结合率。【结果】抗杀虫双、杀螟丹品系小菜蛾的神经乙酰胆碱受体对沙蚕毒素药物有显著的靶标不敏感性,它们与配体的结合率大约分别是敏感品系的66%和60%,在溴氰菊酯抗性品系中没有明显变化。【结论】神经乙酰胆碱受体对杀虫剂敏感性下降可能是小菜蛾对沙蚕毒素药物产生抗性的一种作用机理。     

抗杀虫双和抗杀螟丹小菜蛾的等基因系的培育

将小菜蛾抗性品系与敏感品系杂交，Ｆ１代用能杀死全部敏感个体和部分杂合个体的剂量进行选择；存活人体与敏感品系回交，其后代再用上述适量药剂进行选择；存活个体与敏感品系回交。通过１２代回交，建立了抗杀虫双和抗杀螟丹近等基因系，并对我功能氧化酶环氧化活性和生物学特性进行比较研究。     

小菜蛾对溴氰菊酯的抗性遗传分析

用选育的小菜蛾敏感品系（Ｓ）和抗溴氰菊脂品系（Ｒ）为亲本,采用ＬＤ－Ｐ线法,分析了小菜蛾对溴氰菊酯的抗性遗传方式。结果表明,抗性为常染色体多基因遗传：正、反杂交Ｆ１的显性度Ｄ值分别为－０．５０８４和－０．４５５６,其主效基因为不完全隐性遗传效应。抗性现实遗传力ｈ＾２＝０．１３５,说明抗性产生速率较快,出现高抗生的风险较大。亲本和杂交后代幼虫多功能氧化酶（ＭＦＯ）环氧化活性与溴氰菊酯抗性水平呈正相关性。     

小菜蛾对杀虫双和溴氰菊酯抗性遗传的RDA分析

利用代表性差异分析技术（Representational Difference Analysis,RDA）初步分析了小菜蛾敏感品系及其抗杀虫双和抗溴氰菊酯近等基因系之间的遗传差异。用敏感品系基因组作驱赶扩增子，分别以抗杀虫双和抗溴氰菊酯近等基因系基因组DNA作检测扩增子，通过4轮消减杂交，在抗杀虫双近等基因系基因组中得到2条差异片段（150bp-300bp），两轮消减杂交后，在抗溴氰菊酯近等基因系中也获得了片段（150bp-300bp）。这些结果表明，RDA技术可有效用于小菜蛾抗性分子机理的研究。     

抗杀虫双和抗杀螟丹小菜蛾近等基因系的培育

将小菜蛾抗性品系与敏感品系杂交,Ｆ１代用能杀死全部敏感个体和部分杂合个体的剂量进行选择;存活个体与敏感品系回交,其后代再用上述适量药剂进行选择;存活个体与敏感品系回交。通过１２代回交,建立了抗杀虫双和抗杀螟丹近等基因系,并对其多功能氧化酶环氧化活性和生物学特性进行了比较研究。结果显示：（１）抗杀虫双和抗杀螟丹小菜蛾近等基因系的艾氏剂环氧化活性均高于敏感品系,分别为１．５６倍和１．９７倍;（２）在回交后代中,抗性水平逐代降低。小菜蛾对杀虫双和杀螟丹的抗性并未付出明显的生物学代价。     

生物源杀虫剂对小菜蛾毒效的比较试验

室内测定了6种生物源杀虫剂对小菜蛾卵、初孵幼虫和2龄幼虫的毒力,结果表明,6种生物源杀虫剂对小菜蛾不同虫态的活性差异较大,阿维菌素、菜喜对幼虫活性较高,但无杀卵作用;烟碱则具有明显的杀卵及抑制卵孵化作用,卵孵化率低于5％。对不同作用机制的药剂,生产上可结合使用。     

杀虫剂对小菜蛾的防治研究

用锐劲特、甲维盐、阿维菌素、高效氯氰菊酯对小菜蛾进行田间药效试验。结果表明,锐劲特和甲维盐对小菜蛾的防效基本一致,均优于阿维菌素,明显优于高效氯氰菊酯;且两者均具有高效、低残留、持效期长等特点。因此,锐劲特和甲维盐适宜在无公害蔬菜生产基地推广使用。     

Insensitive Acetylcholine Receptor Conferring Resistance of Plutella xylostella to Nereistoxin Insecticides

The combinative rate measurement of (3-[Ⅰ125] iodotyrosyl) α-bungarotoxin was applied in the analysis of the relation between nerve acetylcholine receptor and three types of insecticide resistance in diamondback moth, Plutella xylostella (L.). In the dimehypo-resistant strain and in the cartap-resistant strain, the nerve acetylcholine receptor showed the remarkable insensitivity to dimehypo and cartap, of which the binding rate to ligand was approximately 66 and 60%, respectively, of the susceptible strain. The sensitivity to deltamethrin in the deltamethrin-resistant strain did not show visible change. These results indicated that the decline in the sensitivity of nerve acetylcholine receptor to insecticide might be a potential mechanism to nereistoxin insecticides resistance in the diamondback moth.     

两种生物杀虫制剂防治蔬菜小菜蛾田间药效试验

两种生物杀虫制剂防治蔬菜小菜蛾试验结果表明：奥绿一号1000倍和触螟1000倍生物药剂对小菜蛾的防治效果分别达到96．18％、95．44％,高于对照化学药剂4．5％高效氯氰菊酯1500倍防效。在无公害蔬菜生产中,奥绿一号、触螟等生物杀虫剂是防治蔬菜害虫理想的药剂,可推广使用。     

Functional identification of C-type lectin in the diamondback moth,Plutella xylostella (L.) innate immunity

C-type lectins (CTLs) are a superfamily of Ca²+-dependent carbohydrate-recognition proteins, and an important pattern recognition receptor (PRR) in insect innate immunity which can mediate humoral and cellular immunity in insects. In this study, we report a novel dual carbohydrate-recognition domain (CRD) CTL from Plutella xylostella which we designate PxIML. PxIML is a protein with a 969 bp open reading frame (ORF) encoding 322 amino acids, containing a signal peptide and a dual-CRD with EPN (Glu₁₂₄-Pro₁₂₅-Asn₁₂₆) and QPD (Gln₂₇₄-Pro₂₇₅-Asp₂₇₆) motifs. The expression of PxIML mRNA in the fat body was significantly higher than in hemocytes and midgut. The relative expression levels of PxIML in the whole insect and the fat body were significantly inhibited after infection with Bacillus thuringiensis 8010 (Bt8010) at 18 h, while they were significantly upregulated after infection with Serratia marcescens IAE6 or Pichia pastoris. The recombinant PxIML (rPxIML) protein could bind to the tested pathogen-associated molecular patterns (PAMPs), and the bacteria of Enterobacter sp. IAE5, S. marcescens IAE6, Staphylococcus aureus, Escherichia coli BL21, and Bt8010 in a Ca²⁺-dependent manner, however, it showed limited binding to the fungus, P. pastoris. The rPxIML exhibited strong activity in the presence of Ca²⁺ to agglutinate Bt8010, Enterobacter sp. IAE5 and S. aureus, but it only weakly agglutinated with E. coli BL21, and could not agglutinate with S. marcescens IAE6 or P. pastoris. Furthermore, the rPxIML could bind to hemocytes, promote the adsorption of hemocytes to beads, and enhance the phenoloxidase (PO) activity and melanization of P. xylostella. Our results suggest that PxIML plays an important role in pathogen recognition and in mediating subsequent humoral and cellular immunity of P. xylostella.     

Insensitive Acetylcholine Receptor Conferring Resistance of Plutella xylostella to Nereistoxin Insecticides

The combinative rate measurement of （3-[I125] iodotyrosyl） α-bungarotoxin was applied in the analysis of the relation between nerve acetylcholine receptor and three types of insecticide resistance in diamondback moth, Plutella xylostella （L.）. In the dimehypo-resistant strain and in the cartap-resistant strain, the nerve acetylcholine receptor showed the remarkable insensitivity to dimehypo and cartap, of which the binding rate to ligand was approximately 66 and 60%, respectively, of the susceptible strain. The sensitivity to deltamethrin in the deltamethrin-resistant strain did not show visible change. These results indicated that the decline in the sensitivity of nerve acetylcholine receptor to insecticide might be a potential mechanism to nereistoxin insecticides resistance in the diamondback moth.     

小菜蛾触角的显微结构及其作用

采用扫描电镜观察小菜蛾触角 ,发现雄蛾有 9种感觉器 ,雌蛾有 8种感觉器 .触角切除试验表明 ,触角是小菜蛾重要的感觉器官 ,在搜寻寄主植物中发挥重要作用     

10%阿维·毒乳油对小菜蛾的田间药效评价

经过两年田间试验结果表明,10%阿维.毒乳油1500m l/hm2,药后3~7d对小菜蛾的防效为85.43%~87.03%,与对照药剂1.8%集琦虫螨克乳油450m l/hm2的防效相当,而与48%毒死蜱乳油600m l/hm2的防效达极显著差异。     

球孢白僵菌对小菜蛾呼吸作用的影响

利用红外 CO2 分析仪测定了小菜蛾感染球孢白僵菌后呼吸节律的变化 .结果表明 ,小菜蛾呼吸节律属于不规则波动型 ,染病幼虫呼出的 CO2 量显著低于对照组 .说明感染球孢白僵菌后 ,小菜蛾幼虫的生理代谢受到干扰 ,呼吸代谢水平降低