Induction of microsomal oxidases by host plants in the fall armyworm,Spodoptera frugiperda (J. E. Smith)

Larvae of the fall armyworm (Spodoptera frugiperda (J. E. Smith)) were maintained on a semidefined artificial diet until the end of the fifth instar and the newly molted sixth-instar larvae were then fed fresh leaves of various host plants for 2 days prior to microsomal oxidase assays. The order of the midgut aldrin epoxidase activity of larvae after feeding on these plants was: corn > Bermuda grass > cotton > cowpeas > cabbage > peanuts > sorghum > alfalfa > millet > soybean. The ratios of aldrin epoxidase, p-nitroanisole O-demethylase, and p-chloro-N-methylaniline N-demethylase activities for soybean- and corn-fed larvae were 4.5, 6.3, and 2.7-fold, respectively. The induction was affected by the age and developmental stage of the corn plant with mature leaves from old plants being more active. Higher epoxidase activities were also observed in mature larvae reared on corn plants since egg stage as compared with those on soybean plants. Monoterpenes such as α-pinene, β-pinene, limonene, menthol, and peppermint oil were found to induce the midgut epoxidase activity. Corn-fed larvae were more tolerant of the insecticides methomyl, acephate, methamidophos, diazinon, trichlorfon, monocrotophos, permethrin, and cypermethrin than soybean-fed larvae.     

虫螨腈胁迫对甜菜夜蛾保护酶系和解毒酶系的诱导效应

为探明虫螨腈对甜菜夜蛾幼虫体内生化代谢的影响及酶抑制剂对虫螨腈的增效潜力,采用点滴法测定了虫螨腈对甜菜夜蛾3、4、5龄幼虫的毒力和顺丁烯二酸二乙酯(DEM)、增效醚(PBO)、磷酸三苯酯(TPP)对虫螨腈的增效作用,并采用生化分析法测定了LD₂₅和LD₅₀剂量虫螨腈对甜菜夜蛾体内保护酶系和解毒酶系的影响。结果表明,虫螨腈对甜菜夜蛾不同龄期幼虫的毒力差异不大,处理后24h和48h的LD₅₀基本相同。PBO对虫螨腈有拮抗作用,增效比为0.21,而DEM和TPP对虫螨腈无增效作用。虫螨腈对甜菜夜蛾幼虫体内超氧化物歧化酶具有激活作用,对过氧化氢酶、过氧化物歧化酶及羧酸酯酶具有先抑制后诱导的作用;虫螨腈处理后6~24h,谷胱甘肽-S-转移酶活性显著提高,最高为对照的1.85倍;处理6h后,甜菜夜蛾体内细胞色素P450含量明显下降,而12~24h后,又明显上升,最高时为对照的1.86倍。     

Insect juvenile hormones: Induction of detoxifying enzymes in the housefly and detoxication by housefly enzymes

The cecropia juvenile hormone and three of its analogs were compared as inducers of microsomal epoxidase, O-demethylase, and DDT dehydrochlorinase in the housefly, Musca domestica L. The compounds were the cecropia juvenile hormone, methoprene, hydroprene, 6,7-epoxy-3,7-diethyl-1-[3,4-(methylenedioxy)phenoxy]-2-octene, and piperonyl butoxide, a well known insecticide synergist. The compounds were administered by feeding at levels up to 1% in the diet for 3 days to 1-day-old female adults. Enzymes were then prepared and assayed for their activity using heptachlor, p-nitroanisole, and DDT as substrates.There was approximately a twofold increase in the microsomal oxidases and a 50% increase in DDT dehydrochlorinase after the treatment with the cecropia juvenile hormone, while methoprene had some activity as an inducer of the epoxidase (30% increase) but no activity in the case of the O-demethylase or the dehydrochlorinase. Hydroprene had no effect on any of the enzyme systems, while 6,7-epoxy-3,7-diethyl-1-[3,4-(methylenedioxy)phenoxy]-2-octene was an inhibitor of the two microsomal oxidases. The latter compound and piperonyl butoxide were strong inducers of DDT dehydrochlorinase, causing approximately twofold increases in the activity of this enzyme.There was evidence that the microsomal preparations were able to metabolize and inactivate methoprene and hydroprene, the action being oxidative in the case of methoprene and both oxidative and hydrolytic in the case of hydroprene. The oxidative metabolism of the two juvenile hormone analogs by the microsomal preparations was inducible by the cecropia juvenile hormone and by phenobarbital and dieldrin.     

取食不同寄主的草地贪夜蛾肠道微生物多样性分析

为绿色防控草地贪夜蛾Spodoptera frugiperda,基于16S rDNA和ITS高通量测序分析,对分别取食玉米、小麦以及田间常见杂草婆婆纳Veronica polita的草地贪夜蛾肠道细菌和真菌进行物种注释、多样性分析、物种组成分析及功能预测。结果显示,细菌注释共获得20门30纲72目106科164属214种,真菌注释共获得9门23纲46目90科154属237种。厚壁菌门、放线菌门和变形菌门为取食玉米、小麦和婆婆纳的草地贪夜蛾肠道优势细菌门,子囊菌门和担子菌门为取食玉米、小麦和婆婆纳的草地贪夜蛾肠道优势真菌门。肠球菌属Enterococcus为取食玉米、小麦和婆婆纳的草地贪夜蛾肠道细菌共同的优势属,相对丰度分别为70.86%、25.42%和72.02%;丝孢酵母属Tricho-sporon 和帚枝霉属 Sarocladium 为取食玉米的草地贪夜蛾肠道真菌的优势属,相对丰度分别为57.28%和17.38%,酵母菌目未分类属、小囊菌属Microascus和丝孢酵母属Trichosporon为取食小麦的草地贪夜蛾肠道真菌优势属,相对丰度分别为29.31%、27.01%和15.45%,双足囊菌科未分类属为取食婆婆纳的草地贪夜蛾肠道真菌优势属,相对丰度为61.79%。取食小麦的草地贪夜蛾肠道细菌群落的多样性最高,取食婆婆纳的草地贪夜蛾肠道真菌群落的多样性最高,取食婆婆纳的草地贪夜蛾肠道细菌和真菌群落的丰富度最高。取食玉米、小麦和婆婆纳的草地贪夜蛾肠道细菌群落功能主要与代谢通路相关,取食玉米、小麦和婆婆纳的草地贪夜蛾肠道真菌群落功能主要与基础代谢或生理功能相关。     

Interactions of allelochemicals with detoxication enzymes of insecticide-susceptible and resistant fall armyworms

The induction of glutathione S-transferases and microsomal oxidases by host plants and allelochemicals was examined in sixth-instar larvae of insecticide-susceptible and resistant strains of the fall armyworm, Spodoptera frugiperda (J. E. Smith). Among 11 host plants studied, parsnip and parsley were the best inducers of glutathione S-transferase, resulting in increases of 39- and 19-fold, respectively, compared with the artificial diet. The inducer in parsnip leaves was identified by mass spectrometry, high-pressure liquid chromatography, gas chromatography, and thin-layer chromatography as xanthotoxin, a furanocoumarin. Xanthotoxin also showed a bimodal effect on the microsomal oxidase systems, increasing cytochrome P-450 content and heptachlor epoxidase activity but inhibiting aldrin epoxidase, biphenyl 4-hydroxylase, and p-chloro-N-methylaniline N-demethylase. Using indole 3-acetonitrile, indole 3-carbinol, and flavone as inducers, the inducing pattern of glutathione S-transferases was the same toward 3,4-dichloronitrobenzene, 1-chloro-2,4-dinitrobenzene, and methyl iodide. Microsomal oxidase and glutathione S-transferase were also inducible by host plants and allelochemicals in larvae of a carbaryl-resistant strain.     

寄主植物对二斑叶螨解毒酶活性的诱导作用

[目的]明确不同蔬菜寄主对二斑叶螨解毒酶活性的诱导影响,为叶螨的寄主适应性及叶螨对寄主的抗性机制研究提供基础.[方法]将饲养在菜豆上的二斑叶螨分别转移到黄瓜、甘蓝和茄子上饲养3代后,测定包括菜豆在内的4种不同寄主植物对叶螨体内解毒酶系活性的诱导影响.[结果]取食不同寄主植物的二斑叶螨体内解毒酶系活性差异显著.从菜豆寄主转养到黄瓜、甘蓝和茄子上后,后3个寄主上叶螨种群体内谷胱甘肽S-转移酶(GST)活性显著下降,茄子上种群活性最低,菜豆种群是茄子种群的2.75倍;而后3个寄主种群的乙酰胆碱酯酶(AChE)比活力显著上升,茄子种群最高,是菜豆种群的6.03倍.4种供试寄主植物的二斑叶螨种群中,在黄瓜寄主上羧酸酯酶(CarE)和多功能氧化酶(MFO)活性显著高于其他3种寄主植物,CarE活性的高低顺序为黄瓜＞菜豆和甘蓝＞茄子,而MFO活性为黄瓜＞茄子和菜豆＞甘蓝.[结论]取食不同寄主植物可诱导二斑叶螨体内的解毒酶系活性发生不同程度的变异,这可能是二斑叶螨对寄主具有广泛适应性的生理基础之一.     

Induction of detoxification enzymes by triazine herbicides in the fall armyworm, Spodoptera frugiperda (J.E. Smith)

The inductive effect of six triazine herbicides on a variety of detoxification enzymes was investigated in fall armyworm (Spodoptera frugiperda) larvae maintained on an artificial diet. Dietary atrazine induced nine microsomal oxidase activities ranging from 1.3- to 21.6-fold, 12 glutathione S-transferase activities ranging from 1.3- to 4.2-fold, four hydrolase activities ranging from 1.3- to 2.9-fold, and two reductase activities ranging from 1.5- to 5.1-fold, depending on the enzyme assayed and tissue source (midgut vs. fat body) used. Simazine, cyanazine, ametryn, tebutryn, and terbuthylazine also induced these detoxification enzymes. The induction of microsomal oxidase (aldrin epoxidase) ranged from 1.2- to 11-fold, glutathione S-transferase (CDNB) ranged from 1.3- to 4-fold, and general esterase ranged from 1.4- to 4.1-fold, depending on the tissue source examined. In general, fat bodies were more inducible than midguts with respect to these detoxification enzymes, especially the microsomal oxidases. The induction by atrazine was associated with decreased toxicity of carbaryl, permethrin and indoxacarb, but increased toxicity of methyl parathion, phorate, and trichlorfon.     

四川省草地贪夜蛾发生为害特点

为探明草地贪夜蛾在四川的发生为害特点,利用田间调查数据对草地贪夜蛾在四川的发生分布范围、受害作物种类、幼虫种群动态和扩散过程进行了分析。结果表明,草地贪夜蛾在四川除阿坝州外的20个市州都有发生,重发区域集中在川东和攀西地区;受害作物以玉米为主,甘蔗、高粱、小麦和油菜零星受害;在攀西地区和川东北地区观察到2个幼虫为害高峰,其余地区只有1个幼虫为害高峰;草地贪夜蛾在攀枝花市和凉山州局部地区为周年繁殖区,其在四川的扩散总体上呈现出由南向北、由东向西的过程。     

Effect of host plants on fitness traits and detoxifying enzymes activity of Helopeltis theivora, a major sucking insect pest of tea

Helopeltis theivora Waterhouse (Heteroptera: Miridae) is a major sucking insect pest of tea (Camellia sinensis) which feeds on a wide variety of alternative host plants. Feeding biology and fitness traits of H. theivora, on two alternative host plants, viz., Mikania micrantha (Asteraceae) and Psidium guajava (Myrtaceae), besides C. sinensis (Theaceae), were studied along with corresponding levels of xenobiotic defense enzymes. C. sinensis is the preferred host of H. theivora. The development time of H. theivora is significantly shorter on C. sinensis (13.3?±?0.16?days) than on the two other hosts, M. micrantha (14.2?±?0.22?days) and P. guajava (14.7?±?0.23?days). Similarly, the fecundity (C. sinensis: 172.6?±?4.5 eggs/female, M. micrantha: 128.6?±?4.4 eggs/female, P. guajava: 118.7?±?3.3 eggs/female), oviposition period (C. sinensis: 24.1?±?0.7?days, M. micrantha: 22.5?±?0.6?days, P. guajava: 21.7?±?0.8?days) and hatchability (C. sinensis: 80.9?±?1.9%, M. micrantha: 69.4?±?1.6%, P. guajava: 64.1?±?1.7%) are recorded to be significantly higher on C. sinensis. The age at reproductive maturity and egg incubation periods were lower on C. sinensis than on the two other host plants. Host-based variation in H. theivora fitness traits is interpreted in light of differential activity of three principal xenobiotic detoxifying enzymes, the general esterases (GEs), glutathione S-transferases (GSTs) and cytochrome P450 monooxygenases (CYPs). The activities of these enzymes in H. theivora were significantly enhanced when the insect fed on M. micrantha and P. guajava as compared with on C. sinensis.     

Induction of microsomal enzymes in the southern armyworm (Prodenia eridania)

Levels of microsomal epoxidation, N-demethylation, and cytochrome P-450 in the gut tissues of sixth instar southern armyworm larvae were considerably enhanced following oral in vivo treatment with a series of methylbenzenes. Induction increased with increasing methyl substitution and was maximal with pentamethylbenzene. The increase in microsomal activity occurred rapidly after initiation of treatment and the final levels of induction achieved were dependent on the concentration of the inducer in the diet and the time of exposure. Microsomal enzyme activity returned to control levels following termination of exposure and induction was blocked by puromycin and cycloheximide but not by actinomycin D. The in vivo tolerance of induced worms to orally administered carbaryl was increased in a manner reflecting the enhanced microsomal enzyme activity.     

取食不同寄主植物的甜菜夜蛾对药剂敏感性的变化

初步探讨了取食不同寄主植物的甜菜夜蛾对药剂敏感性及其体内酶活性的变化。结果表明：取食不同寄主植物的甜菜夜蛾对灭多威、溴氰菊酯的敏感性变化较大，最大LD50之比分别达17．3和44．9倍，而对辛硫磷的敏感性变化不大，最大LD50之比为1．9倍；取食不同寄主植物的甜菜夜蛾体内谷胱甘肽-S-转移酶的活性差异不显著，而羧酸酯酶活性、多功能氧化酶脱甲基作用差异显著，其中羧酸酯酶的活性变化与对灭多威敏感性的变化相一致。因此，羧酸酯酶可能是寄主植物影响甜菜夜蛾对灭多威敏感性变化的因素之一。     

我国草地贪夜蛾的防控对策与建议

草地贪夜蛾Spodoptera frugiperda(J.E.Smith)是世界性重大农业害虫,该虫自2019年1月入侵我国云南省到5月下旬,在不到5个月的时间里就已经入侵了长江流域及其以南的15个省(市、自治区)。预计6月和7月将到达我国的玉米主产区黄淮海夏玉米区和北方春玉米区,受威胁玉米面积1 300多万hm 2,将严重威胁我国的玉米生产安全。我国玉米的种植布局随季节和纬度变化从南至北递次推移,时间和空间上互补,为草地贪夜蛾提供了丰富的食物资源,为其种群区域性迁移和周年繁殖为害提供了良好的自然条件。为做好草地贪夜蛾的防控工作,及时控制其为害,本文在总结国内外防控草地贪夜蛾经验教训的基础上,初步提出了我国草地贪夜蛾的防控对策。     

寄主植物对甜菜夜蛾酯酶活性及杀虫剂敏感性的影响

寄主植物对甜菜夜蛾的生长发育、羧酸酯酶活性及杀虫剂的敏感性有显著影响。取食甜菜、苋菜、甘蓝、青菜的甜菜夜蛾幼虫历期渐次增加 ,蛹重依次降低 ,而酯酶活性依次增大。 4种不同寄主喂养的甜菜夜蛾对功夫菊酯的敏感性与酯酶活性呈明显负相关性。     

Induction of host defence enzymes by the endophytic bacterium Serratia marcescens,in banana plantlets

Pre-inoculation with the endobacterium Serratia marcescens (strain UPM39B3) induced the production of host defence enzymes such as peroxidase, polyphenoloxidase, phenylalanine ammonia lyase, total soluble phenols and lignothioglycolic acid in banana plantlets. The levels of these enzymes were evidently higher in plantlets pre-treated with the endobacterium compared to the control. The production of host-induced enzymes benefitted the crop plants as they may have a role in suppressing Fusarium wilt incidence in the plantlets. This was evident when plantlets pre-treated with the endobacterium showed a lower disease severity (50%) compared to diseased plantlets lacking the endobacterium (74%). The results of this study thus highlight the potential of the isolate Serratia marcescens (strain UPM 39B3) as a biological control agent for Fusarium wilt management in bananas, reducing disease severity via stimulation of host defences.     

Host plant induction of glutathione S-transferase in the fall armyworm

The influence of various host plants on glutathione S-transferase activity was studied in the fall armyworm, Spodoptera frugiperda (J. E. Smith). Fall armyworm larvae were maintained on a semidefined artificial diet until the end of the fifth instar. The newly molted sixth instar larvae were then fed fresh leaves of various host plants for 2 days prior to glutathione S-transferase assays using 3,4-dichloronitrobenzene as substrate. The order of the midgut glutathione S-transferase activity of larvae after the worms fed on these plants was: mustard > turnip > cowpeas > peanuts > cotton > corn > cucumber > potato > Bermudagrass > millet > sorghum > soybeans. The difference in the transferase activity between soybean- and mustard-fed larvae was 10-fold. Kinetic study revealed a quantitative, but no qualitative difference in the glutathione S-transferase between soybean- and cowpea-fed larvae. Monoterpenes, such as α-pinene, β-pinene, menthol, and peppermint oil, had no effect on the enzyme. Cowpea-fed larvae were more tolerant of the insecticides diazinon, methamidophos, and methyl parathion than soybean-fed larvae were. These new observations help explain what has been happening in the field and might be of use in the development of pest management programs.     

寄主植物对甜菜夜蛾种群动态的影响

为了明确甜菜夜蛾在藜、苋菜、甜菜和葱上的种群动态,通过室内试验,测定了4种寄主植物对甜菜夜蛾生长发育和繁殖等种群增长参数的影响,组建了甜菜夜蛾在供试植物上的实验种群生命表。结果表明,取食苋菜和藜的幼虫发育历期最短,而取食葱的发育历期最长(平均为16.00d)。蛹的发育历期在藜上最短(8.70d),在苋菜上最长(10.30d)。寄主植物不影响甜菜夜蛾卵的孵化率和蛹的存活率,但影响幼虫的存活率。幼虫的存活率在藜上最高(74.67%),葱上最低(26.25%)。藜、苋菜、甜菜和葱上甜菜夜蛾单雌平均产卵量分别为589.80、376.40、454.60、532.70粒。甜菜夜蛾雌蛾在藜、苋菜、甜菜、葱上的产卵呈现明显的动态变化。取食藜组和甜菜组雌蛾的产卵高峰出现在羽化后第2天,苋菜组为羽化后第3天,而葱组则为羽化后第1天和第3天。甜菜夜蛾在藜上的种群净增殖率(R0)、内禀增长率(rm)和周限增长率(λ)最高,平均世代周期(T)、种群加倍时间(t)最低。4种寄主植物中,甜菜夜蛾的适宜寄主植物依次为藜、苋菜、甜菜和葱。     

寄主植物对草地螟中肠解毒酶及保护性酶活性的影响

[目的]探讨寄主植物对草地螟中肠解毒酶及保护性酶活性的影响,为研究草地螟对不同寄主植物的生理适应机制奠定基础。[方法]测定草地螟幼虫取食藜、大豆、向日葵、玉米和马铃薯等5种不同寄主植物后中肠解毒酶羧酸酯酶、谷胱甘肽S-转移酶、乙酰胆碱酯酶和保护酶超氧化物歧化酶、过氧化氢酶、过氧化物酶活力的时序变化。[结果]取食不同寄主植物会显著影响幼虫中肠解毒酶活性。取食适宜寄主植物时幼虫中肠解毒酶活力在初期明显高于取食非适宜寄主植物的,但随着取食时间的延长,取食非适宜寄主植物的酶活力快速增长。取食初期,取食不同寄主植物对于中肠保护酶活性也有一定影响,但随着取食时间的延长,保护酶活力基本趋于一致。[结论]试验结果表明,草地螟老龄幼虫中肠解毒酶和保护酶对不同寄主的适应性反应是其取食非适宜寄主能够存活的生理机制之一。     

Induction effects of host plants on insecticide susceptibility and detoxification enzymes of Bemisia tabaci (Hemiptera: Aleyrodidae)

BACKGROUND: The polyphagous B‐biotype Bemisia tabaci (Gennadius) has developed a high resistance to commonly used insecticides in China. To illustrate the induced changes by host plant, bioassay and biochemical research on five different host populations were investigated. RESULTS: Except for bifenthrin, all tested insecticides showed lower toxicity to the B. tabaci poinsettia population compared with other host populations. Moreover, four insecticides, the exceptions being abamectin and fipronil, showed highest toxicity towards the tomato population. The LC₅₀ values of the poinsettia population, particularly towards acetamiprid, were 14.8‐, 10.3‐ and 7.29‐fold higher than those of tomato, cucumber and cabbage respectively. The CarE activities of B. tabaci cabbage and cucumber populations were all significantly higher than those of poinsettia, cotton and tomato populations. The ratio of the cabbage population was 1.97‐, 1.79‐ and 1.30‐fold higher than that of poinsettia, cotton and tomato respectively. The frequency profiles for this activity also have obvious differences. The GST and P450 activities of the cucumber population were the lowest in the five host populations. CONCLUSION: Long‐term induction of host plants for B‐biotype B. tabaci could influence their susceptibilities to several insecticides. Rational selection and usage of insecticides for particular hosts will be helpful for resistance management and control of this species. Copyright © 2010 Society of Chemical Industry     

中国不同地区草地贪夜蛾种群生物型分子特征分析

原产于美洲的草地贪夜蛾已入侵我国,对我国粮食生产安全构成重大威胁。在美洲,该虫的寄主类型、迁飞行为以及抗药性等方面因群体分化而存在较大差异。本研究利用2个分子标记对中国13省(市、自治区)131个县市的318份样品进行群体遗传特征比较,基于线粒体COⅠ基因分析结果显示96%以上为水稻型,玉米型比例不到4%,且中国样品COⅠ序列特征与美国佛罗里达州种群有很高的一致性,而基于核基因组Tpi基因分析结果表明所有样品单倍型特点均表现为玉米型。分析认为,入侵我国的草地贪夜蛾群体很可能来自一个水稻型母本和玉米型父本杂交群体的后代,在长期的演化扩散过程中,玉米型的核基因组占据了主导地位,从而成为一种特殊的玉米型。厘清入侵中国的草地贪夜蛾具体的遗传特征属性,对于风险评估、精准监测和科学防控具有重要指导意义。