虫害诱导的植物挥发性次生物质及其对寄生蜂的招引作用

在植物—植食性昆虫—寄生蜂三级营养系统中,虫害诱导的植物挥发性次生物质是当前害虫生物防治、化学生态学和昆虫行为学研究的热点之一。本文概述了虫害诱导的植物挥发性次生物质的特性及其对寄生蜂的招引作用,可望为害虫生物防治研究提供参考。     

植物挥发物在寄生蜂寄主定位中的作用

植物挥发物在寄生蜂的寄主栖息地定位中起着重要作用。在自然状态下,某些健康植物能释放对寄生蜂有吸引作用的挥发物。当植物受到植食性昆虫为害后,可引起植物的间接防御,即产生对一定种类寄生蜂具引诱作用的挥发物来保护自己。此外,害虫的产卵也能诱导部分植物产生引诱天敌的物质。对于植食性昆虫取食植物诱导的挥发物研究较深入,而其产卵对植物挥发物的影响研究较少。本文主要综述近年国内外有关植物挥发物对寄生蜂寄主定位影响的研究概况,可望为害虫综合治理研究提供参考。     

植食性昆虫唾液调控昆虫-植物互作的研究进展

在与寄主植物长期共同进化的过程中,为了更好地适应和利用寄主,植食性昆虫进化出了多种取食方式。同时,为了应对植食性昆虫的取食,植物进化出了多种防御策略,包括直接防御和间接防御。在整个昆虫-植物互作过程中,昆虫唾液起着重要作用。一方面,昆虫唾液中一些组分可以被植物识别并诱导植物防御反应;另一方面,昆虫通过分泌唾液到植物中调控寄主防御反应。该文从昆虫-植物互作的角度出发介绍植食性昆虫唾液的成分与功能,着重对昆虫唾液激发子和效应子的研究进展进行了综述,并对未来唾液的研究及其在害虫防治中的应用进行展望。     

植物-植食性昆虫互作关系中早期信号事件研究进展

诱导防御反应的产生取决于植物对植食性昆虫相关信号迅速和准确地识别。在植物与植食性昆虫互作过程中,早期信号事件是负责植物识别和触发下游信号转导途径的最早反应,它们发生在植物防御相关基因表达和防御相关代谢物产生之前,对植物的防御过程至关重要。本文将植物与植食性昆虫互作的早期事件,包括植物对植食性昆虫的感知、电信号和Ca~(2+)信号的产生和转导,活性氧的迸发以及促细胞分裂原活化蛋白激酶(MAPK)信号级联途径等研究进展进行了综述,并提出今后的研究重点与方向,促进对植物诱导防御反应调控网络的研究,以期为改进农业害虫的治理提供重要的理论和技术支撑。     

虫害诱导植物间接防御机制

自然界中的植食性昆虫本身都具有一定的隐蔽保护性,这为害虫防治带来了一定的难度。寄生性天敌（寄生蜂等）能够利用嗅觉感受来自寄主和植物的化学通讯来搜索、定位、发现和寄生目标害虫。本文着重综述了植物与害虫协同进化所形成的防御策略,以及害虫诱导的植物挥发信息物质在植物、昆虫及天敌三级营养关系中的生态功能,并对挥发物的诱导信号分子、基本特性、占主要成分的萜烯类化合物释放的分子调控机制、植物组织中时空表达特异性和多样性等代谢特征以及其应用前景都进行了详细阐述。     

植物病原菌的生物控制

植物病害的生物防治,对保证充分利用各种防治方法具有广泛的意义。生物防治策略包括三项关键措施,即控制害虫种群数量、排除害虫及作物的自身防御。这些措施为植保工作者进行生物防治研究提供了重要的理论依据。植物、昆虫与微生物之间相互联系的生态学,是生物防治的一个重要领域,更深刻地理解这些生物的生态学有助于发现更实际的生物控制因子。     

绿僵菌与植物的多重关系及其在植物保护中的应用潜力

绿僵菌是广为知晓的昆虫病原真菌,被用作生物杀虫剂防治多种农林植物害虫。近年发现它也是根际微生物群落的一员,且有证据表明它内生于一些植物的根组织中,具有促进植物生长、拮抗植物病原菌、诱导植物抗性等作用。本文着重综述绿僵菌根际作用和植物内生性研究进展,从对植物的直接作用角度,了解其田间生态适应性及与植物的互作关系,以拓展昆虫病原真菌作为植物保护剂的认识,有助于根据生态学特点制定未来的生物防治应用策略。     

昆虫化学生态学研究进展及未来展望

昆虫化学生态学是化学生态学的重要组成部分,在理论和应用上都有重要意义,是植物保护的重要理论基础。国际昆虫化学生态学经历了4个发展阶段,随着分子生物学和生物技术的应用,化学生态学已经进入分子时代。我国昆虫化学生态学在昆虫化学感受机理、昆虫信息素的鉴定和利用、植物信息化学物质对昆虫行为的调控机理和利用、植物与昆虫互作化合物的开发利用等理论和应用研究方面取得了很大成就,但从系统性、深入性和延续性来说,与国际水平尚有一定差距。本文在综述国内外昆虫化学生态学进展的基础上,提出了我国昆虫化学生态学研究的几个发展方向及措施。     

利用化学激发子防控作物害虫研究进展

诱导防御反应是植物抵御害虫为害的一种重要机制。在这一防御机制中,各种化学激发子,包括植食性昆虫相关分子模式、植物激素及其类似物、植物激发子多肽等发挥着重要作用。合理开发利用这些化学激发子,可望帮助植物建立一种天然的防御体系,从而降低害虫种群密度、减轻害虫为害,减少化学农药使用量。本文将主要对诱导植物抗虫性的化学激发子的最新研究成果进行概述,并展示利用化学激发子防控田间作物害虫的最新研究案例,提出亟待解决的问题,以促进化学激发子在作物害虫防控中的应用。     

植物病毒与媒介昆虫互作促进其传播的研究进展

近年来植物病毒病频发,严重制约着农作物的产量与品质。绝大多数植物病毒依赖媒介昆虫进行传播,而传播的关键是病毒如何突破昆虫的肠屏障、唾液腺屏障和卵屏障等多个生物屏障。植物病毒一方面利用其外壳蛋白或非结构蛋白突破媒介昆虫的中肠屏障和唾液腺屏障;另一方面则与昆虫体内卵黄原蛋白、共生菌以及精子表面蛋白发生特异性互作,促进病毒跨越卵障碍,最终实现病毒在昆虫体内复制。此外,植物病毒还能通过侵染寄主植物影响其防御性状,间接改变媒介昆虫生理及其行为反应,促进病毒在植物间的传播。该研究对植物病毒突破昆虫生物屏障的分子机制,以及植物病毒-植物-媒介昆虫互作对于病毒传播的影响进行了综述,并对阻断病毒传播的方法进行展望。     

Manipulation of parasitoids for aphid pest management: progress and prospects

This paper describes research at IACR-Rothamsted on aphid parasitoid responses to semiochemical foraging stimuli, aimed at developing novel ways of manipulating these behaviours to overcome ecological constraints to biological and integrated pest control. Female parasitoids respond both to aphid sex pheromones acting as kairomones, and to aphid-induced plant volatiles, acting as synomones. A range of economically important parasitoid species respond to aphid sex pheromones, and their potential for enhancing parasitization of aphid populations has been demonstrated in the field. Commercial production of the pheromone from the plant Nepeta cataria L has been developed and strategies for its use in arable crops are being investigated. Aphid-induced plant volatiles are released systemically throughout the plant and are aphid species specific, probably induced by elicitors in aphid saliva. Aphid-infested plants can induce uninfested neighbours to release damage-related volatiles, plant-to-plant communication occurring via the rhizosphere. The plant compound cis-jasmone has been identified as a plant signal with potential for aphid control, inducing plant defence mechanisms that both deter colonising aphids and attract parasitoids and predators. Such compounds may represent a new generation of crop protectants and their further investigation and development will be aided by the tools generated by genomic and post-genomic biology.     

植物次生代谢物质和害虫防治

植物次生代谢物质从其生物合成途径可以将次生物质分成酚类、类萜、含氮化合物和其他次生物质4大类。 植物次生代谢物质对害虫有忌避和毒杀作用,引诱害虫在寄主上产卵,使其后代有较好生存环境。植物次生物质吸 引传粉昆虫繁衍后代,同时也吸引某些共生生物。植物次生代谢物质在昆虫和植物协同进化中具有信号转递功能。     

Population density and feeding duration of cabbage looper larvae on tomato plants alter the levels of plant volatile emissions

BACKGROUND: As part of their indirect defense, plants under herbivore attack release volatile chemicals that attract natural enemies of the herbivore. This is a very well-documented phenomenon. However, relatively few studies have investigated the response of plants to different population levels of herbivores and their feeding duration. RESULTS: Working with larvae of the cabbage looper, Trichoplusia ni (Hübner), and tomato plants, Lycopersicon esculentum Mill cv. clarence, and using an ultrafast gas chromatograph (the zNose™) for volatile analyses, the authors studied the effect of larval density and feeding duration on levels of plant volatile emissions. Intense herbivory caused higher emission levels of the herbivore-induced plant volatiles (HIPVs) (Z)-3-hexenyl acetate, (E)-β-ocimene and β-caryophyllene than those caused by moderate herbivory. When herbivory had ceased following 12–24 h of larval feeding, plants kept releasing HIPVs at a high level for a longer period of time than they did following only 6 h of larval feeding. The plants' slow adjustment in their volatile emissions following prolonged larval feeding might be strategic, as such feeding is more likely to have ceased just temporarily. CONCLUSION: This information may help in the development of a pest monitoring system that is based on herbivore-induced plant volatiles. Copyright © 2011 Society of Chemical Industry     

Olfactory response of the ladybird beetle <Emphasis Type="Italic">Stethorus gilvifrons</Emphasis> to two preys and herbivore-induced plant volatiles

The spider mites Tetranychus urticae Koch and Panonychus ulmi (Koch) (Tetranychidae) cause severe economic losses to vegetable farms and deciduous fruit orchards in Turkey. One of their predators, the ladybird beetle Stethorus gilvifrons (Muls.) (Col., Coccinellidae), aggregates on mite-infested patches of plants. The present study assessed whether there is a role for herbivore-induced plant volatiles (HIPVs) and/or odors emitted directly from these two mite species in the aggregative response of ladybird beetles. The olfactory responses of the predator females to volatiles from T. urticae- and/or P. ulmi-infested sweet pepper (four cultivars, viz. ‘Demre’, ‘Yalova Carliston’, ‘Kandil Dolma’ and ‘Yag Biberi’), kidney bean (cv. ‘Barbunya’) and apple (M9 rootstock) were investigated using a two-choice olfactometer. Our results showed that HIPVs emitted from both T. urticae- and P. ulmi-infested plants significantly attracted S. gilvifrons adults for all plants except the sweet pepper cv. Yag Biberi. In addition, it was found that volatiles from apple plants infested by T. urticae and, especially, P. ulmi are more attractive for S. gilvifrons females than those emitted by other infested plants. The results also suggest that the odors of T. urticae adults and their products might influence the attraction of S. gilvifrons females.     

Induction of phenylalanine ammonia-lyase (PAL) in insect damaged and neighboring undamaged cotton and maize seedlings

There has been scepticism about plants responding to information from their damaged neighbor plants since it was first reported, although a growing body of evidence indicates that interplant communication may play a key role in the resistance of plants. Cotton aphids and corn borer are important insects in cotton and maize, respectively. The resistance of healthy cotton and maize plants induced by their neighbor damaged plants was investigated in this study. Phenylalanine ammonia-lyase (PAL) is a chemical marker of induced resistance in many plants. The enzymatic activity and gene expression of PAL were determined in cotton and maize seedlings damaged by wounding, aphid and corn borer attack and in intact undamaged maize and cotton seedlings growing nearby. The enzymatic activity and gene expression of PAL were significantly increased in the cotton and corn seedlings damaged by wounding or by aphid and corn borer. Furthermore, undamaged neighboring cotton and maize seedlings also showed elevated enzymatic activity and gene expression of PAL. These inductions of PAL enzymatic activity and gene expression in the damaged and undamaged seedlings suggest inter-species communication between cotton and maize.     

Effects of jasmonic acid-induced resistance in rice on the plant brownhopper, Nilaparvata lugens Stål (Homoptera: Delphacidae)

It has been established that jasmonate and its pure derivative, Jasmonic Acid can induce the emission of volatiles similar to those induced by herbivory which fed on the plant. Although the effects of induced resistance on chewing insects have been extensively studied, relatively little is known about their potential effects on phloem-feeding insects such as brown planthoppers. We studied the pattern of within-plant preference in the brown planthopper, Nilaparvata lugens (Stål) (BPH) (Homoptera: Delphacidae) and its consequences for offspring performance on the host-plant Oryza sativa L. (Taebaegbyeo variety) regarding the role of induced resistance of rice plants to hopper feeding. The present study examined the effects of induced resistance on the feeding (food assimilation and digestion), development, egg hatchability and survival. In this study, induced resistance was activated in rice using a foliar application of synthetic jasmonic acid (JA) (low 2.5 mM and high 5 mM). Induced resistance significantly reduced the longevity and egg hatchability of the adult N. lugens, as well as the percentage of nymphs surviving to maturity (only at high dose). This study also observed N. lugens food utilization, in order to evaluate the potential influence of induced resistance on N. lugens feeding behavior. The quantity of food ingested and assimilated by N. lugens on JA treated rice plants was significantly affected at the high dose of JA. These results indicate that JA application induces systemic defenses in rice that have a direct negative impact on N. lugens survivorship. At high concentration (5 mM) several abnormalities possibly related to defective moulting, were observed along with malformed eggs. These findings expand our knowledge the effects of JA-dependent defenses on phloem-feeding insects.     

植物挥发性次生物质对植食性昆虫的影响

植物挥发性次生物质对植食性昆虫的寄主选择、取食、交配、产卵等行为有着重要的影响作用。本文就植物挥发性次生物质对植食性昆虫影响的研究状况及其进展进行综述报道,以便为进一步深入开展这方面的研究提供借鉴。     

Natural extracts from pepper,wild rue and clove can activate defenses against pathogens in tomato plants

Tomato is an important species grown in many countries, either in fields or greenhouses. Despite decades of improvement, it is still susceptible to diseases, thus requiring the use of chemical pesticides, especially in greenhouses. Nevertheless it is imperative to reduce the use of environmental-unfriendly phytochemicals and favor less toxic tools to fight pathogens. Plants possess elaborate mechanisms against diseases that can lead to resistance. In the present work, we investigate the induction of plant defenses by means of extracts from plants widespread and easy to find, also known for their antimicrobial properties. Aqueous extracts of pepper ‘Rocoto’, wild rue and ethanolic extracts of clove powder (whose inhibiting effect was assessed on Oidium sp. spores) were tested on tomato plants for their ability to induce expression of different defense genes (PRs and regulatory proteins) after spraying. As revealed by RT-qPCR, all extracts were able to induce mRNA accumulation of different PR and MAPK regulators for several hours upon treatment, with clove and wild rue being the strongest. This effect could also be reproduced in tomato plants after a second treatment, 15 days after the first. The same extracts were tested in tomato and tobacco plants via leaf infiltration, showing necrotic symptoms associated with the hypersensitive response, thus confirming the priming capacity of the extracts. The involvement of salicylic acid (SA) in these responses was verified by HPLC analysis and in SA-depleted transgenic tobacco (NahG). The results obtained suggest that natural antimicrobial extracts can be used to induce plant defenses and protect valuable crops. At the same time these low-cost extracts do not pose a threat to the environment or the farmer and can help reduce the farming costs, especially in developing countries.