植物和刺吸式口器昆虫的诱导防御与反防御研究进展

刺吸式口器昆虫在长期的进化过程中形成特殊的口针结构,用于专门吸食植物韧皮部筛管细胞的汁液成分.以蚜虫为例,它们在取食过程中分泌的胶状唾液和水状唾液将有效的降低植物防御反应,其中水状唾液包含的大量酶类不仅可以帮助蚜虫穿刺植物韧皮部,刺探到筛管细胞,同时也是植物感受蚜虫为害的激发因子,诱导出植物防御反应和相关抗性基因的表达...     

韧皮部取食昆虫诱导的植物防御反应

刺吸式昆虫与寄主植物之间具有特殊的生物互作关系。本文对刺吸式昆虫取食韧皮部诱导的植物防御反应类型、 防御物质变化、 信号途径以及植物反应转录组学研究等方面进行综述。韧皮部取食昆虫取食诱导的植物防御反应机制主要包括： (1)改变自身的营养状况; (2)产生有毒的次生化合物; (3)产生防御蛋白。防御反应与植物水杨酸、 茉莉酸、 乙烯等信号分子密切相关。研究表明, 刺吸式昆虫取食诱导的植物防御反应主要引发以水杨酸为主的信号途径, 但相关分子互作机制还有待明确。日益丰富的基因组资源和不断发展的分子生物学技术为揭示植物防御反应中信号分子的作用机制、 找出植物内生抗性的特异因子以及阐明诱导防御机制奠定了基础。了解刺吸式昆虫取食诱导的植物防御反应, 为深入理解植物-昆虫间协同进化关系提供了依据, 为害虫治理和抗虫植物的培育提供了新的思路。     

昆虫唾液成分在昆虫与植物关系中的作用

近年来,人们对于植食性昆虫唾液的深入研究,揭示出其在昆虫与植物的相互关系和协同进化中起到非常重要的作用。植食性昆虫唾液中含有的酶类和各种有机成分,能诱导植物的一系列生化反应,而且这些反应有很强的特异性,与为害的昆虫种类甚至龄期有关。鳞翅目幼虫口腔分泌物（或反吐液）中含有的β-葡糖苷酶、葡萄糖氧化酶等酶类和挥发物诱导素等有机成分,已经证明可以诱导植物的反应; 刺吸式昆虫的取食也可以刺激植物产生反应,但其唾液内的酶类,如烟粉虱的碱性磷酸酶, 蚜虫的酚氧化酶、果胶酶和多聚半乳糖醛酸酶, 蝽类的寡聚半乳糖醛酸酶等是否发挥作用,目前还没有直接的证据。寄主植物对昆虫的唾液成分也有很大的影响,可能是昆虫对不同植物营养成分和毒性成分的适应方式。对昆虫唾液蛋白的分析表明,具有同样类型口器、食物类型接近的昆虫,唾液成分有更多的相似性。研究植食性昆虫的唾液成分,对于阐明昆虫和植物的协同进化关系、昆虫生物型的形成机理、害虫的致害机理,以及指导害虫防治等,有着一定的理论和实际意义。     

一种烟粉虱成虫唾液酶鉴定与活性分析的方法

以B型烟粉虱Bemisia tabaci(Gennadius)成虫为材料,介绍了一种微型刺吸式昆虫唾液酶鉴定和分析的方法,主要包括人工饲养、唾液收集、唾液多酚氧化酶(PPO)和过氧化物酶(POD)的鉴定与活性分析。结果显示,B型烟粉虱在特异性嗜好寄主甘蓝上分泌的多酚氧化酶与过氧化物酶的比活力分别为嗜好寄主番茄上的1.54和1.65倍。该方法操作简捷,鉴定结果直观清晰,酶活测定灵敏,适合于其他微型刺吸式昆虫如蚜虫、木虱等的唾液酶研究。     

寄主植物与刺吸式昆虫互作防御的研究进展

寄主植物与昆虫在长期协同进化中形成了复杂的防御和反防御机制。本文系统综述了寄主植物与刺吸式昆虫互作防御的过程与机制。刺吸式昆虫利用特化的口针,吸食寄主植物组织汁液时,植物通过细胞膜表面或细胞内受体感知昆虫取食信号,并经过丝裂原活化蛋白激酶(mitogen-activated protein kinase, MAPK)信号通路、植物激素信号通路、钙离子信号通路、转录因子调控、Rop/Rac GTPase信号通路、活性氧(reactive oxygen species, ROS)通路等信号转导通路激活植物免疫。为了阻止害虫进一步取食,寄主植物形成了增强的物理屏障,并诱导产生次生代谢物、抗营养酶类、抗消化酶类和胼胝质沉积及释放挥发物等多种防御机制。在与寄主植物“博弈”的过程中,刺吸式昆虫往往会利用其取食时分泌的唾液成分,靶向植物靶标蛋白,通过破坏宿主植物的物理屏障,或抑制宿主植物的抗性信号转导,或抑制宿主次生代谢物的毒害作用,或通过跨界RNA和水平基因转移等方式抑制植物的防御反应,从而达到继续取食为害的目的。此外,基于植物与病原菌互作模式,结合寄主植物与刺吸式昆虫互作研究进展,总结了寄主植物...     

植物与植食性昆虫相互作用的分子机制

在长期的协同进化中,植物建立起应对昆虫取食为害的精密而又复杂的防御机制,植物转录组调控中防御应答基因的表达及防御物质的合成因不同的昆虫取食方式而异。一般来说,咀嚼式口器昆虫取食时造成大面积组织伤害,可诱导植物产生伤害反应;而刺吸式口器昆虫因其特殊的口针取食,诱导植物激活病原体相关的防御途径。不同的防御途径激活不同的识别机制和信号途径。本文从信号识别和转导上综述了不同食性的昆虫取食植物时所引发的防御反应,分析了昆虫-植物相互作用关系的分子机制。     

烟粉虱MEAM1隐种漆酶-1基因全长cDNA克隆、序列分析与组织表达

多酚氧化酶是多种刺吸式昆虫唾液中的关键酶类,可以通过干扰寄主植物正常的氧化还原反应来调控食物来源使其更有利于昆虫本身。昆虫体内的漆酶-1属于多酚氧化酶家族,被认为参与昆虫取食过程中的金属离子代谢、降解植物次生有毒物质以及免疫防御等生理活动。为研究漆酶-1基因在烟粉虱MEAM1隐种Bemisia tabaci Middle East-Asia Minor 1组织中的功能,利用RACE技术首次获得了烟粉虱MEAMI隐种漆酶-1（laccase-1,lac-1）基因的cDNA全长序列,命名为Btlac-1 ( GenBank 登录号： JQ966215）。结果表明,该基因含有一个2 733 bp的开放阅读框,编码910个氨基酸,其编码产物含有3个Cu-oxidase功能域, 属于蓝多铜氧化酶家族成员。同源性比较分析表明,Btlac-1与黑尾叶蝉Nephotettix cincticeps和豌豆蚜Acyrthosiphon pisum的lac-1编码的氨基酸序列一致性达58%。Btlac-1在不同组织和发育时期的转录表达分析表明, Btlac-1在烟粉虱MEAM1隐种中肠中的转录水平最高,显著高于头胸部和腹部组织中,且在各个发育时期均有表达,在成虫期的表达水平较高。该结果为进一步明确lac-1在烟粉虱取食过程的生理作用奠定基础,也为探讨刺吸式昆虫与植物相互作用机制提供理论依据。     

伤害和挥发物对棉花花外蜜的诱导效应

植物花外蜜的分泌是一种植物间接防御反应。为了明确植食性昆虫、机械伤和机械伤诱导的挥发性气体在植物花外蜜诱导分泌中的作用,分析了咀嚼式口器昆虫棉铃虫Helicoverpa armigera(Hübner)、刺吸式口器昆虫棉蚜Aphis gossypii Glover取食、剪刀机械伤、剪刀机械伤+棉铃虫反吐物、针刺机械伤以及机械伤诱导挥发物、顺式-茉莉酮对棉花Gossypium hirsutum L.叶片花外蜜分泌量的影响。结果表明,棉铃虫取食、剪刀机械伤、剪刀机械伤+棉铃虫反吐物处理均显著增加了被处理叶片花外蜜的分泌量。棉花花外蜜的诱导效应在处理叶片上表现明显,并且在较幼嫩的第3片真叶上也有系统性增长。顺式-茉莉酮和机械伤挥发物处理1 d对棉花较幼嫩的第4、5片真叶花外蜜有诱导效应。棉花叶片花外蜜的诱导主要与植物组织损伤有关;不同口器类型的昆虫对棉花叶片花外蜜的诱导量不同,咀嚼式口器的棉铃虫对棉花花外蜜的诱导强度显著高于刺吸式口器的棉蚜;顺式-茉莉酮和机械伤诱导的挥发物能作为棉花植株间交流的信息物质诱导棉花幼嫩叶片花外蜜的分泌。     

蚜虫唾液蛋白研究进展

蚜虫属于半翅目蚜科,多为重要的农业害虫,通过刺吸式口器吸食植物汁液,传播病毒,其爆发常常造成重大经济损失。在漫长的协同进化历程中,植物建立了高效的防御系统以应对蚜虫威胁。为了克服植物的防御反应,蚜虫也发展了相应的反制手段,其中蚜虫在取食过程中分泌的唾液蛋白能调控植物防御反应,降解植物次生物质,从而在蚜虫与植物互作中发挥着至关重要的作用。本文综述了蚜虫唾液蛋白的组分鉴定方法和相关蛋白的功能,并对唾液蛋白在蚜虫防治的应用和今后的研究方向进行了展望。常见的蚜虫唾液蛋白组分的鉴定和分析方法包括唾液蛋白的酶活性分析、唾液蛋白组学分析、唾液腺转录组学和蛋白组学分析等。但这些方法各有利弊,仅采取一种分析方法不能客观全面地反映蚜虫唾液蛋白分泌谱,多种技术手段联合分析方可提供更为逼真详实的信息。蚜虫唾液蛋白种类繁多,可分为解毒酶、保护酶、水解酶、结合功能蛋白以及分类未知的效应蛋白等。蚜虫唾液蛋白功能多样,能参与唾液鞘的形成,诱导植物防御反应,促进蚜虫取食,提高蚜虫繁殖力等。通过RNAi干扰唾液蛋白编码基因会显著改变蚜虫取食行为,并降低蚜虫存活率、产蚜量和适合度。因此,唾液蛋白是防控蚜虫的理想靶标。目前,采用寄主诱导的基因沉默(host-induced gene silencing, HIGS)技术已培育了数种靶向唾液蛋白基因的高效抗蚜作物品系,展示出了良好的应用前景。从目前研究来看,各种蚜虫唾液蛋白谱急需采用多组学手段联合分析的方法来进行完整解析。各种唾液蛋白的具体功能方面的研究还严重缺乏,需从蚜虫、植物、两者之间的互作等多维度探究唾液蛋白的作用及相关的分子机制,为发展基于蚜虫唾液蛋白调控的蚜虫防治新策略打下基础。     

应用鸟枪法LC-MS/MS鉴定烟粉虱唾液蛋白

烟粉虱是一种刺吸式口器小型昆虫,每年对我国农业生产造成巨大危害。烟粉虱在取食植物时分泌多种唾液蛋白帮助其取食,同时唾液中的效应因子在调控植物防御反应过程中发挥重要作用。由于烟粉虱个体微小,唾液收集十分困难,有关其唾液蛋白的研究难以开展。本研究收集了3万头烟粉虱唾液,利用高精度Q-Exactive质谱,采用shotgun的方法首次鉴定了烟粉虱唾液中蛋白组分。应用双层膜收集装置收集到的烟粉虱唾液经浓缩等处理后其蛋白浓度约为1.698 g/L。唾液蛋白样品经胶内酶解、LC-MS/MS检测、序列分析,最终鉴定出42个烟粉虱唾液蛋白。功能分析表明烟粉虱唾液蛋白组分与蚜虫唾液蛋白组分具有一定的相似性,但多数蛋白为功能未知蛋白。通过质谱鉴定烟粉虱唾液蛋白组分为深入研究烟粉虱唾液蛋白的功能奠定了基础,有利于明确烟粉虱危害寄主植物的分子机制,为开发害虫防治新方法提供新思路。     

植食性昆虫唾液效应子和激发子的研究进展

植食性昆虫与寄主植物通过协同进化形成了复杂的防御和反防御机制.本文系统综述了昆虫唾液效应子和激发子在植物与昆虫互作中的作用及机理.昆虫取食中释放的唾液激发子被植物识别而激活植物早期免疫反应,昆虫也能从口腔分泌效应子到植物体内抑制免疫;抗性植物则利用抗性(R)蛋白识别昆虫无毒效应子,启动效应子诱导的免疫反应,而昆虫又进化...     

Volatile emission in wheat and parasitism by Aphidius avenae after exogenous application of salivary enzymes of Sitobion avenae

Enzymes in the saliva of the English green aphid, Sitobion avenae (F.) (Homoptera: Aphididae), may be responsible for inducing indirect defence in wheat. In this study, we examined the effects of exogenous application of three salivary enzymes of S. avenae , namely, polyphenol oxidase, pectinase, and cellulase, on the release of volatiles from wheat and the attractiveness of these volatiles to the parasitoid Aphidius avenae Haliday (Hymenoptera: Aphidiidae). In greenhouse experiments, parasitism of S. avenae on plants surrounded by pectinase-treated plants and aphid-damaged plants was significantly higher than parasitism of aphids on plants surrounded by cellulase- and polyphenol oxidase-treated plants. In Y-tube olfactometer tests, female A. avenae significantly preferred the volatiles collected from pectinase-treated plants and aphid-damaged plants. Gas chromatography-mass spectrometry analysis showed that two kinds of semiochemicals, sulcatol and sulcatone, were identified only in pectinase-treated plants and aphid-damaged plants. In field experiments, parasitism of S. avenae by A. avenae was significantly higher on plants sprayed with a mixture of sulcatol and sulcatone than parasitism on plants sprayed with volatiles collected from cellulase- and polyphenol oxidase-treated plants. These results show that pectinase in S. avenae watery saliva can trigger wheat plant indirect defence, and play a crucial role in interaction between wheat, wheat aphid, and A. avenae .     

Composition and variability of the saliva of coreids in relation to phytoxicoses and other aspects of the salivary physiology of phytophagous Heteroptera

In the saciform, principal salivary glands ofMictis profana (Fabr.) (Coreidae: Heteroptera, Pentatomorpha), the contents of all lobes other than the posterior form gels consistent with their contributing to the solidifying saliva (stylet sheath); the posterior lobe secretes most if not all of a sucrose-hydrolysing enzyme that occurs in the nongelling (watery) saliva. Evidence for the occurrence of such an enzyme in the saliva of other coreids is presented. That inM. profana has a pH optimum near neutral and a substrate specificity consistent with sucrase (sucrose α-D-glucohydrolase, EC 3.2.1.48) as distinct from plant invertase (β-D-fruccofuranosidase, EC 3.2.1.26). Apart from some maltose-hydrolysing activity in the salivary glands, also consistent with sucrase, no other carbohydrases and neither proteinase nor lipase were detected. Phosphatases were found in gland extracts but not in secreted saliva. The saliva contains catechol oxidase (EC 1.10.3.1) from the accessory gland and ducts. Topical application of pilocarpine caused individualM. profana to secrete up to 58 μl watery saliva which showed continuous and independent variation of sucrase activity (up to ca 0.012 Units/μl) and pH (6–8), although high sucrase content tended to coincide with high pH. Total protein varied up to 10 μg/μl, and free amino acids up to 1.8 μg/μl leucine eq. Of the many proteins and/or protein subunits separable by electrophoresis of gland contents and saliva, four had sucrase activity, the most mobile with MW ca 66 000. TLC indicatedinter alia phenyl alanine and tyrosine, but no DOPA nor other diphenolic substrates of the catechol oxidase in the watery saliva. The soluble components of the saliva, which also has marked surfactant properties, are discussed in relation to the feeding process of coreids and the characteristic lesions they produce in their food plants.     

Perception of insect feeding by plants

The recognition of phytophagous insects by plants induces a set of very specific responses aimed at deterring tissue consumption and reprogramming metabolism and development of the plant to tolerate the herbivore. The recognition of insects by plants requires the plant’s ability to perceive chemical cues generated by the insects and to distinguish a particular pattern of tissue disruption. Relatively little is known about the molecular basis of insect perception by plants and the signalling mechanisms directly associated with this perception. Importantly, the insect feeding behaviour (piercing‐sucking versus chewing) is a decisive determinant of the plant’s defence response, and the mechanisms used to perceive insects from different feeding guilds may be distinct. During insect feeding, components of the saliva of chewing or piercing‐sucking insects come into contact with plant cells, and elicitors or effectors present in this insect‐derived fluid are perceived by plant cells to initiate the activation of specific signalling cascades. Although receptor–ligand interactions controlling insect perception have yet not been molecularly described, a significant number of regulatory components acting downstream of receptors and involved in the activation of defence responses against insects has been reported. Some of these regulators mediate changes in the phytohormone network, while others directly control gene expression or the redox state of the cell. These processes are central in the orchestration of plant defence responses against insects.     

Quantitative proteomic analysis of the fall armyworm saliva

Lepidopteran larvae secrete saliva on plant tissues during feeding. Components in the saliva may aid in food digestion, whereas other components are recognized by plants as cues to elicit defense responses. Despite the ecological and economical importance of these plant-feeding insects, knowledge of their saliva composition is limited to a few species. In this study, we identified the salivary proteins of larvae of the fall armyworm (FAW), Spodoptera frugiperda; determined qualitative and quantitative differences in the salivary proteome of the two host races—corn and rice strains—of this insect; and identified changes in total protein concentration and relative protein abundance in the saliva of FAW larvae associated with different host plants. Quantitative proteomic analyses were performed using labeling with isobaric tags for relative and absolute quantification followed by liquid chromatography-tandem mass spectrometry. In total, 98 proteins were identified (>99% confidence) in the FAW saliva. These proteins were further categorized into five functional groups: proteins potentially involved in (1) plant defense regulation, (2) herbivore offense, (3) insect immunity, (4) detoxification, (5) digestion, and (6) other functions. Moreover, there were differences in the salivary proteome between the FAW strains that were identified by label-free proteomic analyses. Thirteen differentially identified proteins were present in each strain. There were also differences in the relative abundance of eleven salivary proteins between the two FAW host strains as well as differences within each strain associated with different diets. The total salivary protein concentration was also different for the two strains reared on different host plants. Based on these results, we conclude that the FAW saliva contains a complex mixture of proteins involved in different functions that are specific for each strain and its composition can change plastically in response to diet type.     

灰飞虱唾液腺三大解毒酶家族的转录组分析

灰飞虱Laodelphax striatellus （Fallén）是危害多种禾本科经济作物的重要刺吸式害虫。唾液腺对刺吸式口器昆虫取食植物尤其重要, 其分泌的唾液可以帮助刺吸式口器昆虫刺穿植物、 消化食物、 解毒植物的次生物质。细胞色素P450单加氧酶（cytochrome P450 monooxygenase, P450）、 谷胱甘肽S 转移酶（glutathione S transferase, GST）和羧酸酯酶（carboxylesterase, CarE）是昆虫主要的解毒酶系。为了分析解毒酶基因在灰飞虱唾液腺中的表达谱, 本研究对灰飞虱成虫唾液腺进行转录组测序、 重头组装和注释, 并与豌豆蚜Acyrthosiphon pisum和西方蜜蜂Apis mellifera的同源蛋白进行系统发育分析。发现有9个谷胱甘肽S 转移酶（glutathione S transferase, GST）基因、 22个羧酸酯酶（carboxylesterase, CarE）基因和39个细胞色素P450单加氧酶（cytochrome P450 monooxygenase, P450）基因在灰飞虱唾液腺中表达。通过对同源蛋白进行系统发育分析, 发现灰飞虱唾液腺大部分的CarE是参与消化/解毒和激素/信息素的加工, 而参与神经/发育的CarE很少; 灰飞虱唾液腺表达的P450基因远远少于豌豆蚜和西方蜜蜂基因组的P450基因数, 且只有CYP6和CYP4家族的成员; GST家族在3种昆虫的保守性最高。研究结果为灰飞虱对寄主植物和杀虫剂的适应性研究奠定了基础。     

Effector proteins that modulate plant--insect interactions

Insect herbivores have highly diverse life cycles and feeding behaviors. They establish close interactions with their plant hosts and suppress plant defenses. Chewing herbivores evoke characteristic defense responses distinguishable from general mechanical damage. In addition, piercing-sucking hemipteran insects display typical feeding behavior that suggests active suppression of plant defense responses. Effectors that modulate plant defenses have been identified in the saliva of these insects. Tools for high-throughput effector identification and functional characterization have been developed. In addition, in some insect species it is possible to silence gene expression by RNAi. Together, this technological progress has enabled the identification of insect herbivore effectors and their targets that will lead to the development of novel strategies for pest resistances in plants.