昆虫共生菌调控宿主温度适应性研究进展

昆虫普遍会感染多种共生菌,共生菌在其宿主的生理、生态及进化等方面发挥着至关重要的作用。近年来大量研究表明,昆虫与共生菌的共生关系易受环境温度变化的影响;同时,共生菌直接或间接参与调控昆虫宿主对温度胁迫的响应。该文综述了温度对昆虫与共生菌共生关系的影响和昆虫共生菌在宿主温度适应中的作用、潜在机制及其生态学意义;并基于当前共生菌调控昆虫温度适应性方面的研究进展,建议后续可聚焦于自然条件下变温胁迫对昆虫与共生菌互作的影响、共生菌调控昆虫适应性进化的行为及分子机制和基于共生菌的害虫防治新手段开发与应用等方面开展研究。该文可为全球气候变化和极端温度频发背景下昆虫与共生菌的协同进化研究以及利用共生菌进行害虫防控工作提供参考。     

油菜素内酯调控植物响应非生物逆境胁迫的生理机制

油菜素内酯属于甾体类激素中的油菜素甾醇类物质，是其生物合成中产生的活性副产物，对植物生长发育具有重要的调节作用。在非生物胁迫条件下，外源施用油菜素内酯可以增强植物的抗氧化系统，增加渗透物质水平，维持内源激素平衡，稳定离子和水分平衡，改善气体交换属性和光合作用，最终减轻逆境危害并促进植物生长。该文综述油菜素内酯对非生物胁迫下植物生长、生理调节的影响及调控途径，对油菜素内酯提高植物抗逆境能力的未来研究方向进行展望。     

植物防御中茉莉酸信号通路抑制与终止的作用机制

茉莉酸（jasmonate,JA）作为重要的植物激素,在平衡植物生长发育和响应外界胁迫中发挥着重要作用。植物响应外界胁迫主要是通过激活信号转导通路实现信号传递的级联放大信号进而实现防御响应。然而,植物防御是一个高能耗过程,防御的适时抑制与终止有利于植物的生长发育。针对植物茉莉酸信号通路的抑制与终止研究,总结参与防御相关茉莉酸信号通路抑制与终止的主要调控因子,阐述茉莉酸ZIM结构域蛋白（jasmonate ZIM-domain,JAZ）、髓细胞组织增生蛋白2（myelocytomatosis 2,MYC2）、JA相关类MYC2蛋白（JA-associated MYC2-like,JAM）和MYC2直接调控bHLH蛋白（MYC2-targeted BHLH,MTB）等对茉莉酸信号通路进行抑制与终止的作用机制,总结抑制茉莉酸信号通路的茉莉酸代谢途径,最后对茉莉酸信号通路抑制与终止机制的研究方向进行展望。     

昆虫共生菌调控宿主生长发育和生殖的研究进展

共生菌参与昆虫宿主的多种生理活动,而昆虫则为共生菌提供了良好的增殖环境,两者互利共生。共生菌的种类、丰度和功能均因昆虫种类和发育阶段的不同而有所差异。该文总结了昆虫共生菌研究概况及已报道的昆虫共生菌种类,重点介绍了共生菌调控昆虫宿主生长发育和生殖的研究进展,包括共生菌通过协助宿主营养代谢及抵御病原菌来调控宿主的生长发育速率;胞内共生细菌沃尔巴克氏体Wolbachia通过胞质不亲和、雌性化、雄性致死以及诱导孤雌生殖调控宿主的生殖力;胞外共生细菌则通过参与宿主营养代谢、改变宿主生殖行为和影响宿主生殖细胞来调控昆虫宿主的生殖力,以及共生菌调控宿主生殖的可能分子机制。同时,该文还在深入探讨共生菌功能、拓宽研究宿主种类及共生菌在抗菌防虫中的应用等方面进行了展望。共生菌对昆虫宿主生长发育和生殖调控作用的研究有助于进一步揭示昆虫与共生菌的协同进化机制,并为进一步利用共生菌进行害虫治理奠定理论基础。     

小麦种质 Edinburgh-b 白粉菌侵染下的基因表达谱分析

 Edinburgh-b是从英国爱丁堡引进的小麦抗白粉病新种质,为了深入了解该种质的抗白粉病分子机制,本研究采用Agilent公司的4 SymboltB@ 44 k小麦表达谱芯片,以Edinburgh-b接种白粉菌0 h为对照,分析其在白粉菌胁迫下的基因表达谱。结果表明,在43 603个探针中筛选出差异表达探针5 835个,其中上调表达2 801个,下调表达3 034个。差异表达基因主要包括与代谢相关的酶类、转录因子、病程相关蛋白、防卫反应基因和信号传导因子等。Pathway分析显示苯丙烷类生物合成、水杨酸信号通路、茉莉酸生物合成、活性氧代谢等被激活,乙烯生物合成和生长素信号通路被抑制,推测水杨酸和茉莉酸信号通路共同参与了Edinburgh-b对白粉菌的防御反应。选取上调和下调表达共17个基因进行实时定量RT-PCR验证,表明基因芯片数据具有良好的重复性。     

环境胁迫下昆虫的耐寒适应机制研究进展

昆虫是变温动物,为了安全越冬,昆虫通常改变自身结构和物质构成以适应低温的到来,这一适应机制与体内特殊的生理生化物质紧密相关,如海藻糖、葡萄糖、甘油、山梨醇、脂肪酸和氨基酸等小分子抗冻保护剂。这些抗冻保护剂具有稳定细胞膜结构和保护蛋白质功能的作用。虽然昆虫耐寒性的研究不断深入,但目前我们仍然很难确定影响耐寒的关键因素是什么?为什么有些昆虫在低于-20℃环境下还能存活?为了弄清这一科学问题,科学家们利用转录组、基因组、蛋白质组和代谢组等各种组学剖析低温胁迫后昆虫生理反应的分子机制。本文旨在综述前人对昆虫耐寒性的研究,为将来其他昆虫或动植物的耐寒性研究提供参考依据。同时,也为新型生物农药的开发和天敌昆虫的人工助增提供广阔思路。     

昆虫神经内分泌研究的生物技术应用展望

昆虫的激素主要有三种,蜕皮激素、保幼激素与神经激素。另外,前列腺素、生物胺、雌性激素有时也作为昆虫激素。迄今,昆虫内分泌研究主要集中在蜕皮激素类与保幼激素类,原因是这些激素的分子相对简单,能制约蜕皮与变态这两个关键过程。打破这两个生理过程就能有效地防治害虫。不少保幼激素类似物能干扰变态与生殖,已商品化地应用于蝇、蚊、跳虱、(虫非)蠊等害虫的防治。神经激素一般是肽,因此结构变化比蜕皮激素及保幼激素大。尽管有关神经激素的资料不多,但从长远来看,其应用于害虫防治的潜力要出蜕皮激素和保幼激素大。它们是昆虫主要的调控因子,影响很多的生理过程,如保幼激素与蜕皮激素的分泌,以及生长、变态、生殖,自发生理平衡等,大约有24例研究报道,指称神经激素能调节昆虫的生长与发育、生殖、代谢与生理的自发平衡等生理过程。但仅有极少数昆虫神经激素被分离,提取,完全或部分地搞清它的化学结构。本文论述以神经内分泌为基础的害虫防治有关事项。     

昆虫性别决定机制研究进展及展望

昆虫在进化过程中发展出多种决定性别的调控机制。不仅不同昆虫通过不同的基因和调控机制决定性别分化，甚至在同种昆虫不同品系之间性别决定机制也不尽相同。了解昆虫性别决定分子调控机制，不仅有利于揭示昆虫性别的产生与进化，而且为昆虫的遗传操作提供理论和实践基础。本文综述了不同昆虫中的性别决定原始信号及其调控机制，介绍了昆虫性别决定底层基因doublesex和性别决定关键基因transformer、transformer-2的研究概况，以期为靶标昆虫性别决定的害虫不育防治技术提供理论支持。     

干旱胁迫下桑树活性氧信号传导及转录组分析

对干旱胁迫处理后的桑树幼苗(‘湖桑32’和‘德果1号’)进行ROS信号组织定位和叶的转录组测序，旨在从细胞和分子角度探究干旱胁迫后ROS信号在桑树组织细胞中的分布规律及与之相关的代谢通路和基因调控表达变化。结果表明:在正常情况下桑叶组织细胞中会产生少量的■，而干旱胁迫处理后桑叶组织细胞中ROS积累增多，推测ROS作为一种动态信号分子，会向毗邻细胞或远端细胞进行信号转导，进而与多种信号组分共同完成系统响应表达以调控桑树的生长发育及抗逆性。转录组数据表明:重度干旱胁迫处理后‘湖桑32’有5677个差异表达基因显著多于‘德果1号’(5575)，且差异显著基因(DEGs)主要富集在半乳糖代谢、淀粉和蔗糖代谢、果糖和甘露糖代谢、碳代谢等通路中，推测‘湖桑32’的抗旱性与渗透调节物质的合成有关。同时，挑选11个基因进行qRT-PCR验证，其中11个DEGs的表达趋势与对应的RNA-Seq数据一致。研究也发现调控MKK4/5和WRKY22表达的相关基因LOC21384958和LOC21396104，在弱抗旱桑‘德果1号’中分别上调表达0.72(P<0.05)和2.16(P<0.05)，而...     

组蛋白修饰调控植物水杨酸信号转导的研究进展

真核生物中组蛋白翻译后共价修饰直接影响染色质空间结构变化,调控相关基因表达,在植物胁迫应答过程中起重要作用。水杨酸(salicylic acid,SA)作为植物中关键信号分子,诱导多种病毒、真菌及细菌病害抗性。本文简要介绍了植物细胞对病原菌的感知、转导信号产生与防御系统激活机制,着重阐述了组蛋白甲基化、乙酰化、SUMO化修饰、组蛋白变体H2A.Z等如何参与调控水杨酸转导途径应答基因的转录表达。     

Adipokinetic hormone (Pyrap‐AKH) enhances the effect of a pyrethroid insecticide against the firebug Pyrrhocoris apterus

BACKGROUND: Adipokinetic hormones (AKHs) are insect neuropetides controlling stress situations including those elicited by insecticide treatment. The effect of Pyrap‐AKH on the mortality of the firebug Pyrrhocoris apterus (L.) treated with the insecticide permethrin (Ambush 25 EC) was studied. RESULTS: Coinjection of 50 ng permethrin with 80 pmol Pyrap‐AKH induced a significant 2.3‐fold increase in bug mortality compared with the insecticide alone. The results were confirmed by topical coapplication of both agents (400 ng and 80 pmol respectively). Injections of 50 and 100 ng permethrin elicited a significant increase in the AKH level in CNS and the haemolymph. The results indicate an involvement of AKH in stress response to permethrin. The enhanced effect of insecticide by AKH treatments probably results from the stimulatory role in bug metabolism: carbon dioxide production was increased 3.5‐ and 2.5‐fold respectively 1 and 3 h after permethrin treatment, and 4.3‐ and 3.4‐fold after the permethrin plus AKH cotreatment, compared with the control. CONCLUSION: The elevation of metabolism could intensify the permethrin action by its faster penetration into tissues and by stimulation of biochemically active cells, and could be a reason for enhanced action of permethrin after its cotreatment with Pyrap‐AKH. Copyright © 2009 Society of Chemical Industry     

Physiological and structural aspects of adipokinetic hormone function in locusts

During trivial flight in locusts, carbohydrates are the main energy source for the flight muscles, but during long-term (migratory) flight, lipids mobilised from the fat body are utilised. The supply of fuels to the flight muscles, and the balance between fuels, is determined by peptidic adipokinetic hormones, AKH-I and AKH-II, released from the corpora cardiaca. These peptides also indirectly effect changes in lipid-transporting mechanisms in the haemolymph, and regulate a lipoprotein lipase necessary for lipid uptake by the flight muscles. The sequences of the AKHs of locusts are known and they are members of a family of invertebrate neuropeptides. Extensive structure/activity studies for the action of AKHs on lipid mobilisation have been carried out and, together with studies on secondary structure, the structural features necessary for biological activity are being elucidated. Such information will be of great importance in receptor studies for these hormones, and in the development of powerful agonists and antagonists.     

Cross-protection interactions in insect pests: Implications for pest management in a changing climate

Agricultural insect pests display an exceptional ability to adapt quickly to natural and anthropogenic stressors. Emerging evidence suggests that frequent and varied sources of stress play an important role in driving protective physiological responses; therefore, intensively managed agroecosystems combined with climatic shifts might be an ideal crucible for stress adaptation. Cross-protection, where responses to one stressor offers protection against another type of stressor, has been well documented in many insect species, yet the molecular and epigenetic underpinnings that drive overlapping protective responses in insect pests remain unclear. In this perspective, we discuss cross-protection mechanisms and provide an argument for its potential role in increasing tolerance to a wide range of natural and anthropogenic stressors in agricultural insect pests. By drawing from existing literature on single and multiple stressor studies, we outline the processes that facilitate cross-protective interactions, including epigenetic modifications, which are understudied in insect stress responses. Finally, we discuss the implications of cross-protection for insect pest management, focusing on the consequences of cross-protection between insecticides and elevated temperatures associated with climate change. Given the multiple ways that insect pests are intensively managed in agroecosystems, we suggest that examining the role of multiple stressors can be important in understanding the wide adaptability of agricultural insect pests. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Insect midgut structures and molecules as targets of plant‐derived protease inhibitors and lectins

The midgut of insects is involved in digestion, osmoregulation and immunity. Although several defensive strategies are present in this organ, its organization and function may be disturbed by some insecticidal agents, including bioactive proteins like lectins and protease inhibitors (PIs) from plants. PIs interfere with digestion, leading to poor nutrient absorption and decreasing amino acid bioavailability. Intake of PIs can delay development, cause deformities and reduce fertility. Ingestion of PIs may lead to changes in the set of proteases secreted in the insect gut, but this response is often insufficient and results in aggravation of the malnutrition status. Lectins are proteins that are able to interact with glycoconjugates, including those linked to cell surfaces. Their effects on the midgut include disruption of the peritrophic matrix, brush border and secretory cell layer; induction of apoptosis and oxidative stress; interference with nutrient absorption and transport proteins; and damaging effects on symbionts. In addition, lectins can cross the intestinal barrier and reach the hemolymph. The establishment of resistant insect populations due to selective pressure resulting from massive use of a bioactive protein is an actual possibility, but this can be minimized by the multiple mode‐of‐action of these proteins, mainly the lectins. © 2018 Society of Chemical Industry     

A review on the mechanisms involved in hyperglycemia induced by organophosphorus pesticides

Organophosphorus (OP) compounds are cholinesterase-inhibiting chemicals used as pesticide. Exposures to OPs cause a significant number of poisonings and deaths each year. One of the reported adverse effects in human exposure to OPs is hyperglycemia. Animal studies have also shown altered glucose homeostasis following acute or chronic exposures to OPs. The objective of this paper is to provide a brief review of the mechanisms involved in the OP-induced glucose homeostasis alteration. To reach this objective, a search of the literature using Medline/Index Medicus, Scopus, and Chemical Abstract were performed, most of relevant citations were studied and summarized. To better understand the nature of glucose homeostasis, the principles of glucose production, metabolism, and its hormonal control have been discussed. Collection of theses studies support the conclusion that hyperglycemia is the outcome of acute or chronic exposure to OPs. OPs can influence body glucose homeostasis by several mechanisms including physiological stress, oxidative stress, inhibition of paraoxonase, nitrosative stress, pancreatitis, inhibition of cholinesterase, stimulation of adrenal gland, and disturbance in metabolism of liver tryptophan.     

Toxicology of insecticides to mammals

Many insecticides target structures or functions in non-target species, including mammals. This is particularly true of those that target the insect nervous system, such as the organochlorines, anticholinesterases and GABA antagonists. Another group of insecticides target structures or functions not present in mammals, and this group of insecticides has considerable target species specificity, but there are often potential targets in mammals. Octopamine is closely related to adrenaline and amitraz (an octopamine receptor agonist) and acts in mammals at α2-adrenergic receptors. Although there are potential targets in mammals for juvenile hormone mimics and ecdysone receptor agonists, there is no evidence that the mammalian toxicity of either group is related to their insecticidal activity. Nor do chitin synthesis inhibitors have high mammalian toxicity. Copyright © 2012 Society of Chemical Industry     

Signal Interactions in Induced Resistance to Pathogens and Insect Herbivores

Plants are often simultaneously challenged by pathogens and insects capable of triggering an array of responses that may be beneficial or detrimental to the plant. The efficacy of resistance mechanisms can be strongly influenced by the mix of signals generated by biotic stress as well as abiotic stress such as drought, nutrient limitation or high soil salinity. An understanding of their biochemical nature, and knowledge of the specificity and compatibility of the signaling systems that regulate the expression of inducible responses could optimize the utilization of these responses in crop protection. Signaling conflicts and synergies occur during a plant's response to pathogens and insect herbivores, and much of the research on defense signaling has focused on salicylate- and jasmonate-mediated responses. We will review our results using tomato (Lycopersicon esculentum) in greenhouse and field studies that illustrate a trade-off between salicylate- and jasmonate-mediated signaling, and discuss research on strategies to minimize the trade-off that can occur following the application of chemical elicitors of resistance. In addition, there is evidence of another signaling system that mediates endogenous levels of ceramide in the plant. This signal is associated with programmed cell death and protection of tomato against the fungal pathogen Alternaria alternata f. sp. lycopersici.     

Epidemiological survey of Phthorimaea operculella granulosis virus in Tunisia

In Tunisia, Phthorimaea operculella is an important pest in traditional, unrefrigerated potato stores. An integrated control approach including the use of biological control agents and specifically insect viruses is being developed. From this perspective, we carried out a screening and an evaluation of local Phthorimaea operculella granulosis virus naturally present in Tunisian pest populations. On the basis of symptomatology, P. operculella larvae were collected from different regions (North, Cap Bon, Sahel). Indirect ELISA using a serum raised against the purified Tunisian isolate of the virus was used to establish the geographical distribution of the virus. Comparison of the two approaches showed that symptomatology is not so virus-specific, as morphologically healthy insects were sometimes ELISA-positive. The serological technique therefore gives better detection of the virus.     

海藻糖合成酶结构及其抑制剂的研究进展

海藻糖是自然界中广泛存在的非还原性二糖,具有重要的生物学功能.除了可作为储能物质参与机体能量代谢外,更重要的是还可作为结构物质参与真菌细胞壁和昆虫体壁的形成,决定病原菌的致病性或调控昆虫的生长发育.海藻糖合成酶主要负责催化海藻糖的生物合成,包括海藻糖-6-磷酸合成酶和海藻糖-6-磷酸磷酸酯酶两个功能域.近年来,越来越多...     

昆虫生长调节剂的开发现状与发展趋势

本文简要地介绍了与环境友好，相容的昆虫生长调节剂包括几丁质抑制剂，保幼激素类似物和蜕皮激素似物的开发现状和发展趋势，昆虫生长调节剂的发展虽缓慢，但前景广阔。