RNAi技术——植食性害螨防控的新策略

植食性害螨因其个体小、繁殖快、适应性强及易产生抗药性等特点,生产上迫切需要特异性较强、开发成本较低、安全绿色的防控新技术或策略.RNA干扰可以特异性地沉默靶标生物特定基因的表达,从而干扰靶标生物的正常生长及其对寄主植物的危害,最终达到保护植物的目的.目前,RNAi主要集中在对昆虫的研究上,而对于体型微小的农业重要害螨关注不多,故本文围绕RNA的作用原理、在害螨上的应用现状等方面进行简要综述,详细介绍了基于RNAi的技术在农业害螨防控上的可行性以及限制其进一步发展的解决办法.相信,随着RNAi技术的不断成熟,基于RNAi防治害螨的技术有望替代或辅助化学杀螨剂成为害螨防控的新策略.     

草地贪夜蛾潜在RNAi靶标致死基因及纳米载体介导RNAi技术的应用和展望

草地贪夜蛾Spodoptera frugiperda是一种世界性重大农业害虫,在全球多个国家普遍发生,其幼虫可为害玉米、水稻等多种农作物。该虫于2019年初入侵我国,对我国农业生产构成了严重的威胁,防控形势严峻。为寻求一种草地贪夜蛾的绿色防控方法,本文对草地贪夜蛾潜在RNA干扰(RNA interference,RNAi)靶标致死基因、RNAi传统双链RNA(double-stranded RNA,dsRNA)递送技术的瓶颈以及纳米载体介导的RNAi技术应用进行概括,并对纳米载体介导的RNAi技术应用前景进行展望。     

RNAi技术在农业害虫防治中的应用研究进展

RNA干扰(RNA interference,RNAi)是指由内源或外源的双链RNA(double-stranded RNA,dsRNA)引发的mRNA降解,导致特异性阻碍靶标基因表达的现象,在昆虫学研究领域中得到广泛应用。如功能基因研究、基因表达调控及信号传导通路、益虫保护、新型农药的开发、害虫防治等。本文总结了RNAi技术应用于害虫防治上的原理,即以miRNA、siRNA及piRNA等小分子RNA介导的基因沉默过程,分析了影响RNAi技术防治效率的因素,如dsRNA导入方式、导入剂量和靶标基因的选择等,旨在进一步探讨RNAi应用于害虫防治的机理和存在问题,为运用RNAi技术防治害虫新思路奠定基础。     

基于RNA干扰的杀菌剂开发及其对化学杀菌剂的影响

RNA干扰(RNA interference, RNAi)是真核生物中高度保守的基因沉默现象，在医药与植物保护领域展现出广阔的应用潜力，相关产品已进入或即将进入医药与杀虫剂市场。近年来，科研工作者在基于RNAi技术的植物病原微生物的防控方面开展了大量研究，取得了进展，但仍无法实现基于RNAi防治植物病原真菌技术的商业化应用。本文概述了RNAi研究从1990年至今的发展历程，从细胞生物学、分子生物学角度提出了RNAi病害防控技术产品化瓶颈问题的新见解，同时讨论了基于RNAi的杀菌剂对传统化学杀菌剂的影响，可为RNAi杀菌剂的创制和应用提供参考。     

寄主诱导的基因沉默技术研究和应用进展

病原真菌严重威胁着农作物的产量和品质,提高作物抗性是病原真菌病害防控的重要措施。寄主诱导的基因沉默(host induced gene silencing,HIGS)技术是在RNA干扰的基础上发展而来,以病原真菌生长发育和侵染过程中的关键基因为靶标,通过在寄主植物中表达这些基因的干扰RNA从而抑制病原真菌中靶标基因的表达,达到抵制病原真菌扩展,提高寄主植物抗病性的目的。近年来,HIGS技术被用于防控多种由病原真菌引起的病害,并取得了明显成效,为植物抗病资源的开发及应用提供了新途径。本文综述了HIGS技术的原理、技术路线、操作方法和国内外的主要研究进展,总结了操作中需要注意的事项,并对该技术的发展趋势和应用前景进行了展望。     

基于RNA干扰的生物农药的发展现状与展望

RNA干扰又称转录后基因沉默,是一种能有效沉默或抑制目标基因表达的新兴基因工程技术。基于RNA干扰的生物农药被认为是未来植保领域的颠覆性技术,将极大改变人类防治农业病、虫、草等有害生物的思路和策略。本文我们简单回顾了RNA干扰的基本作用机制和发展历程,全面总结了RNAi生物农药的研究水平和应用现状,深入分析了RNAi生物农药发展面临的机遇和挑战,以及未来的发展前景。以期为我国RNAi生物农药的研发提供参考。     

RNA干扰在鳞翅目昆虫中的应用研究进展

鳞翅目(Lepidoptera)是昆虫纲中的第二大目,现已经记载的鳞翅目昆虫多达18万个种.鳞翅目昆虫中的许多成员是重要的全球性农业害虫.多数鳞翅目害虫具有繁殖快、危害重、抗药性强及长距离迁飞等特性,对农业生产构成巨大威胁.RNA干扰(RNAi)技术是指通过将目的基因特异性同源双链RNA(dsRNA)导入到细胞内,引起与其同源的mRNA特异性降解,从而达成目标基因表达沉默的一种分子技术.目前该技术已被广泛应用于鳞翅目昆虫的基因功能研究和绿色害虫防治策略探索,并在近年来取得了显著成效和进展.基于此,对RNAi在昆虫中的作用机理进行了归纳和概括,并重点总结和探讨了近年来RNAi技术在鳞翅目昆虫基因功能研究以及鳞翅目害虫防治新方法探索方面取得的新进展,以期为鳞翅目昆虫相关科学研究和生产实践提供参考.     

RNAi基因沉默技术及其在植物抗病性改良中应用的策略

RNAi (RNA interference) 是一种由dsRNA参与、对靶基因表达进行干扰或沉默的现象。由此发展起来的RNAi基因沉默技术已成为当今植物基因功能研究和遗传改良的一个重要手段。该技术已经在靶向病原物(真菌、细菌、病毒和线虫)基因沉默方面得到了广泛的应用,并且产生了一批抗病性增强的转基因植物。人工设计和合成的amiRNAs和ata siRNAs的成功研发加快了RNAi技术的应用。本文对RNAi基因沉默机制、RNAi技术研发进展及其在植物抗病性遗传改良中的应用进行综述,并对其应用策略进行探讨。     

RNA干扰及其在水稻抗病毒基因工程中的应用

RNA干扰(RNA interference,RNAi)是一种基因沉默机制。RNAi作为新兴的基因阻断技术具有明显的优势,已被广泛应用到动植物功能基因组和植物抗病研究中。在抗病毒研究中,人为地将与病毒或宿主基因同源的双链RNA分子导入转基因植株,引起与其同源的基因发生沉默,达到抗病毒的作用。本文主要综述了RNA干扰的相关知识以及在水稻抗病毒基因工程研究中的应用进展。     

喷雾诱导基因沉默技术在植物真菌病害防治中的研究进展

植物病原真菌是农业上的第一大病原菌，能够持续性地给全球的作物和果蔬产量带来严重的损失。目前真菌病害的防治方法主要依赖化学农药的大量使用，这也带来了真菌耐药性、食品安全以及生态环境污染等问题，因此开发应对病原真菌的新型绿色防控技术迫在眉睫。喷雾诱导基因沉默（spray induced gene silencing，SIGS）技术是一种通过外源施用双链RNA或小干扰RNA的方式来控制病原体关键靶标基因的生物技术，是农业生产上颇具潜力的新型绿色防控技术之一，目前已经成功应用于多种病原真菌的防控。本文主要综述了SIGS技术原理及其在植物真菌病害防治研究中的研究进展，旨在为开发用于防治植物病原真菌的生物农药提供研究基础。     

RNAi‐mediated plant protection against aphids

Aphids (Aphididae) are major agricultural pests that cause significant yield losses of crop plants each year by inflicting damage both through the direct effects of feeding and by vectoring harmful plant viruses. Expression of double‐stranded RNA (dsRNA) directed against suitable insect target genes in transgenic plants has been shown to give protection against pests through plant‐mediated RNA interference (RNAi). Thus, as a potential alternative and effective strategy for insect pest management in agricultural practice, plant‐mediated RNAi for aphid control has received close attention in recent years. In this review, the mechanism of RNAi in insects and the so far explored effective RNAi target genes in aphids, their potential applications in the development of transgenic plants for aphid control and the major challenges in this regard are reviewed, and the future prospects of using plant‐mediated RNAi for aphid control are discussed. This review is intended to be a helpful insight into the generation of aphid‐resistant plants through plant‐mediated RNAi strategy. © 2016 Society of Chemical Industry     

Ingested RNA interference for managing the populations of the Colorado potato beetle, Leptinotarsa decemlineata

BACKGROUND: RNA interference (RNAi) is a breakthrough technology for conducting functional genomics studies and also as a potential tool for crop protection against insect pests. The major challenge for efficient pest control using RNAi in the field is the development of efficient and reliable methods for production and delivery of double‐stranded RNA (dsRNA). In this paper, the potential of feeding dsRNA expressed in bacteria or synthesized in vitro to manage populations of Colorado potato beetle, Leptinotarsa decemlineata (Say) (CPB), was investigated. RESULTS: Feeding RNAi successfully triggered the silencing of all five target genes tested and caused significant mortality and reduced body weight gain in the treated beetles. This study provides the first example of an effective RNAi response in insects after feeding dsRNA produced in bacteria. CONCLUSION: These results suggest that the efficient induction of RNAi using bacteria to deliver dsRNA is a possible method for management of CPB. This could be also a promising bioassay approach for genome‐wide screens to identify effective target genes for use as novel RNAi‐based insecticides. Copyright © 2010 Society of Chemical Industry     

Molecular mechanisms influencing efficiency of RNA interference in insects

RNA interference (RNAi) is an endogenous, sequence‐specific gene‐silencing mechanism elicited by small RNA molecules. RNAi is a powerful reverse genetic tool, and is currently being utilized for managing insects and viruses. Widespread implementation of RNAi‐based pest management strategies is currently hindered by inefficient and highly variable results when different insect species, strains, developmental stages, tissues, and genes are targeted. Mechanistic studies have shown that double‐stranded ribonucleases (dsRNases), endosomal entrapment, deficient function of the core machinery, and inadequate immune stimulation contribute to limited RNAi efficiency. However, a comprehensive understanding of the molecular mechanisms limiting RNAi efficiency remains elusive. Recent advances in dsRNA stability in physiological tissues, dsRNA internalization into cells, the composition and function of the core RNAi machinery, as well as small‐interfering RNA/double‐stranded RNA amplification and spreading mechanisms are reviewed to establish a global understanding of the obstacles impeding wider understanding of RNAi mechanisms in insects. © 2018 Society of Chemical Industry     

RNA interference technology in crop protection against arthropod pests,pathogens and nematodes

Scientists have made significant progress in understanding and unraveling several aspects of double‐stranded RNA (dsRNA)‐mediated gene silencing during the last two decades. Now that the RNA interference (RNAi) mechanism is well understood, it is time to consider how to apply the acquired knowledge to agriculture and crop protection. Some RNAi‐based products are already available for farmers and more are expected to reach the market soon. Tailor‐made dsRNA as an active ingredient for biopesticide formulations is considered a raw material that can be used for diverse purposes, from pest control and bee protection against viruses to pesticide resistance management. The RNAi mechanism works at the messenger RNA (mRNA) level, exploiting a sequence‐dependent mode of action, which makes it unique in potency and selectivity compared with conventional agrochemicals. Furthermore, the use of RNAi in crop protection can be achieved by employing plant‐incorporated protectants through plant transformation, but also by non‐transformative strategies such as the use of formulations of sprayable RNAs as direct control agents, resistance factor repressors or developmental disruptors. In this review, RNAi is presented in an agricultural context (discussing products that have been launched on the market or will soon be available), and we go beyond the classical presentation of successful examples of RNAi in pest‐insect control and comprehensively explore its potential for the control of plant pathogens, nematodes and mites, and to fight against diseases and parasites in beneficial insects. Moreover, we also discuss its use as a repressor for the management of pesticide‐resistant weeds and insects. Finally, this review reports on the advances in non‐transformative dsRNA delivery and the production costs of dsRNA, and discusses environmental considerations. © 2017 Society of Chemical Industry     

The role of allelopathy in agricultural pest management

Allelopathy is a naturally occurring ecological phenomenon of interference among organisms that may be employed for managing weeds, insect pests and diseases in field crops. In field crops, allelopathy can be used following rotation, using cover crops, mulching and plant extracts for natural pest management. Application of allelopathic plant extracts can effectively control weeds and insect pests. However, mixtures of allelopathic water extracts are more effective than the application of single-plant extract in this regard. Combined application of allelopathic extract and reduced herbicide dose (up to half the standard dose) give as much weed control as the standard herbicide dose in several field crops. Lower doses of herbicides may help to reduce the development of herbicide resistance in weed ecotypes. Allelopathy thus offers an attractive environmentally friendly alternative to pesticides in agricultural pest management. In this review, application of allelopathy for natural pest management, particularly in small-farm intensive agricultural systems, is discussed.     

Food safety assessment of crops engineered with RNA interference and other methods to modulate expression of endogenous and plant pest genes

Genetically modified crops have been grown commercially for more than two decades. Some of these crops have been modified with genetic constructs that induce gene silencing through RNA interference (RNAi). The targets for this silencing action are genes, either specific endogenous ones of the host plant or those of particular pests or pathogens infesting these plants. Recently emerging new genetic tools enable precise DNA edits with the same silencing effect and have also increased our knowledge and insights into the mechanisms of RNAi. For the assessment of the safety of foodstuffs from crops modified with RNAi, internationally harmonized principles for risk assessment of foods derived from genetically modified crops can be followed. Special considerations may apply to the newly expressed silencing RNA molecules, such as their possible uptake by consumers and interference with expression of host genes, which, however, would need to overcome many barriers. Bioinformatics tools aid the prediction of possible interference by a given RNA molecule with the expression of genes with homologous sequences in the host crop and in other organisms, or possible off‐target edits in gene‐edited crops. © 2020 The Author. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.