雅脊金小蜂在储粮害虫防治中的研究与应用进展

雅脊金小蜂Theocolax elegans (Westwood)是一种体外寄生蜂,世代周期较短,繁殖速度快,寄主多为鞘翅目隐蔽性害虫和鳞翅目害虫,对于防治储粮害虫具有较大的应用潜力。本文对雅脊金小蜂生物学特性、控害能力、大量扩繁及其影响因素、雅脊金小蜂与现有储粮害虫防治技术联合使用等进行综述,重点概述了雅脊金小蜂的寄主定位机制、长翅型雌蜂的繁殖能力以及对寄主的控害能力,总结了温度、粮食品种、寄主种类和共生微生物对雅脊金小蜂的影响,并对雅脊金小蜂在实际应用中的不足进行了讨论,以期为今后开展利用雅脊金小蜂对储粮害虫高效生物防治有所裨益。     

Oligonucleotide Insecticides for Green Agriculture: Regulatory Role of Contact DNA in Plant–Insect Interactions

Insects vastly outnumber us in terms of species and total biomass, and are among the most efficient and voracious consumers of plants on the planet. As a result, to preserve crops, one of the primary tasks in agriculture has always been the need to control and reduce the number of insect pests. The current use of chemical insecticides leads to the accumulation of xenobiotics in ecosystems and a decreased number of species in those ecosystems, including insects. Sustainable development of human society is impossible without useful insects, so the control of insect pests must be effective and selective at the same time. In this article, we show for the first time a natural way to regulate the number of insect pests based on the use of extracellular double-stranded DNA secreted by the plant Pittosporum tobira. Using a principle similar to one found in nature, we show that the topical application of artificially synthesized short antisense oligonucleotide insecticides (olinscides, DNA insecticides) is an effective and selective way to control the insect Coccus hesperidum. Using contact oligonucleotide insecticide Coccus-11 at a concentration of 100 ng/μL on C. hesperidum larvae resulted in a mortality of 95.59 ± 1.63% within 12 days. Green oligonucleotide insecticides, created by nature and later discovered by humans, demonstrate a new method to control insect pests that is beneficial and safe for macromolecular insect pest management.     

Revealing Differential Expression of Phytohormones in Sorghum in Response to Aphid Attack Using the Metabolomics Approach

Sorghum (Sorghum bicolor) is an important multipurpose crop grown worldwide, but like many other crops, it is often threatened by insect pests. Sugarcane aphid (SCA, Melanaphis sacchari Zehntner), for example, is one of the most severe pests in sorghum, which causes plant damage and yield loss. The main objective of this study was to assess the effect of phytohormones on host plant resistance to aphid attack. Two sorghum genotypes, BTx623 (susceptible) and Tx2783 (resistant), were selected for a comparative analysis of differential expression of a group of phytohormones in response to aphid infestation. The quantification of phytohormones through LC-MS demonstrated higher levels of jasmonic acid (JA), salicylic acid (SA), abscisic acid (ABA), and auxins in the resistant genotype infested with SCA. The PCA plot supports the strong differential responses between resistant and susceptible genotypes, indicating a positive correlation between JA and ABA and a negative correlation between SA and auxins. Similarly, RT-PCR results of the phytohormones-related marker genes showed higher expression in the resistant genotype compared to the susceptible one. Furthermore, to corroborate the role of phytohormones in plant defense, the susceptible genotype was treated with SA, JA, and ABA. The exogenous application of SA and JA + ABA significantly reduced plant mortality, aphid number, and damage in the susceptible genotype, suggesting a strong correlation between phytohormones and plant survival. Our findings indicate that phytohormones play positive roles in plant defense against aphids and provide new insights into the molecular mechanisms operating in plants for self-protection. These findings could also stimulate further research into the mystery about the regulation of phytohormone production during plant interaction with aphids.     

Knockdown of the Halloween Genes spook,shadow and shade Influences Oocyte Development,Egg Shape,Oviposition and Hatching in the Desert Locust

Ecdysteroids are widely investigated for their role during the molting cascade in insects; however, they are also involved in the development of the female reproductive system. Ecdysteroids are synthesized from cholesterol, which is further converted via a series of enzymatic steps into the main molting hormone, 20-hydoxyecdysone. Most of these biosynthetic conversion steps involve the activity of cytochrome P450 (CYP) hydroxylases, which are encoded by the Halloween genes. Three of these genes, spook (spo), phantom (phm) and shade (shd), were previously characterized in the desert locust, Schistocerca gregaria. Based on recent sequencing data, we have now identified the sequences of disembodied (dib) and shadow (sad), for which we also analyzed spatiotemporal expression profiles using qRT-PCR. Furthermore, we investigated the possible role(s) of five different Halloween genes in the oogenesis process by means of RNA interference mediated knockdown experiments. Our results showed that depleting the expression of SchgrSpo, SchgrSad and SchgrShd had a significant impact on oocyte development, oviposition and hatching of the eggs. Moreover, the shape of the growing oocytes, as well as the deposited eggs, was very drastically altered by the experimental treatments. Consequently, it can be proposed that these three enzymes play an important role in oogenesis.     

Crosstalk between Nutrition,Insulin, Juvenile Hormone,and Ecdysteroid Signaling in the Classical Insect Model,Rhodnius prolixus

The rigorous balance of endocrine signals that control insect reproductive physiology is crucial for the success of egg production. Rhodnius prolixus, a blood-feeding insect and main vector of Chagas disease, has been used over the last century as a model to unravel aspects of insect metabolism and physiology. Our recent work has shown that nutrition, insulin signaling, and two main types of insect lipophilic hormones, juvenile hormone (JH) and ecdysteroids, are essential for successful reproduction in R. prolixus; however, the interplay behind these endocrine signals has not been established. We used a combination of hormone treatments, gene expression analyses, hormone measurements, and ex vivo experiments using the corpus allatum or the ovary, to investigate how the interaction of these endocrine signals might define the hormone environment for egg production. The results show that after a blood meal, circulating JH levels increase, a process mainly driven through insulin and allatoregulatory neuropeptides. In turn, JH feeds back to provide some control over its own biosynthesis by regulating the expression of critical biosynthetic enzymes in the corpus allatum. Interestingly, insulin also stimulates the synthesis and release of ecdysteroids from the ovary. This study highlights the complex network of endocrine signals that, together, coordinate a successful reproductive cycle.     

Competitive Sperm-Marked Beetles for Monitoring Approaches in Genetic Biocontrol and Studies in Reproductive Biology

Sperm marking provides a key tool for reproductive biology studies, but it also represents a valuable monitoring tool for genetic pest control strategies such as the sterile insect technique. Sperm-marked lines can be generated by introducing transgenes that mediate the expression of fluorescent proteins during spermatogenesis. The homozygous lines established by transgenesis approaches are going through a genetic bottleneck that can lead to reduced fitness. Transgenic SIT approaches have mostly focused on Dipteran and Lepidopteran pests so far. With this study, we provide sperm-marked lines for the Coleopteran pest model organism, the red flour beetle Tribolium castaneum, based on the β2-tubulin promoter/enhancer driving red (DsRed) or green (EGFP) fluorescence. The obtained lines are reasonably competitive and were thus used for our studies on reproductive biology, confirming the phenomenon of ‘last-male sperm precedence’ and that the spermathecae are deployed for long-term sperm storage, enabling the use of sperm from first mating events even after secondary mating events for a long period of time. The homozygosity and competitiveness of the lines will enable future studies to analyze the controlled process of sperm movement into the long-term storage organ as part of a post-mating cryptic female choice mechanism of this extremely promiscuous species.     

反，反-2，4-己二烯醛醋酸酯的合成

以山梨酸为起始原料,经酯化、选择还原和酯化合成反,反-2,4-己二烯醛醋酸酯。山梨酸甲酯的还原反应以氢化铝锂为还原剂,加入无水三氯化铝减弱还原活性,保护共轭双键,收率约79％,高于文献报道。本文方法操作简单易行,对溶剂和设备无特殊要求。     

Response to pheromone traps and disruption of pheromone communication in the lesser peachtree borer and the peachtree borer (Lepidoptera: Sesiidae)

The sex pheromone communication of the lesser peachtree borer,Synanthedon pictipes (Grote and Robinson), and the peachtree borer,Sanninoidea exitiosa (Say), can be disrupted by permeation of the atmosphere with their respective sex pheromones, (E,Z)- and (Z,Z)-3,13-octadecadien-1-ol acetate. The two isomers seemed equally effective against both species. Disruption was greatest when the pheromone was evaporated from the tops of the peach trees; also, pheromone traps placed in the tree tops captured significantly more males than did traps placed lower in the trees. Neither the color nor the directional placement in a tree (NE, NW, SE, SW) of pheromone-baited traps influenced captures of male lesser peachtree borers.Mention of a commercial or proprietary product in this paper does not constitute a recommendation or an endorsement of that product by the USDA.     

Analysis of the Insect OS-D-Like Gene Family

Insect OS-D-like proteins, also known as chemosensory (CSP) or sensory appendage proteins (SAP), are broadly expressed in various insect tissues, where they are thought to bind short to medium chain length fatty acids and their derivatives. Although their specific function remains uncertain, OS-D-like members have been isolated from sensory organs (including the sensillum lymph in some cases), and a role in olfaction similar to that of the insect odorant binding proteins (OBP) has been suggested for some. We have identified 15 new OS-D-like sequences: four from cDNA clones described herein and 11 from sequence databases. The os-d-like genes from the Anopheles gambiae, Apis mellifera, Drosophila melanogaster, and Drosophila pseudoobscura genomes typically have single, small introns with a conserved splice site. Together with all family members entered on GenBank, a total of 70 OS-D-like proteins, representing the insect orders Diptera, Dictyoptera, Hymenoptera, Lepidoptera, Orthoptera, and Phasmatodea, were analyzed. A neighbor joining distance phenogram identified several protein similarity classes that were characterized by highly conserved sequence motifs, including (A) N-terminal YTTKYDN(V/I)(N/D)(L/V)DEIL, (B) central DGKELKXX(I/L)PDAL, and (C) C-terminal KYDP. In contrast, three similarity classes were characterized by their diversion from these conserved motifs. The functional importance of conserved amino acid residues is discussed in relation to the crystal and NMR structures of MbraCSPA6.     

Olfactory orientation responses by walking femaleIps paraconfusus bark beetles I. Chemotaxis assay

Gas-liquid chromatography of the air within the arena developed for this assay showed that a concentration gradient was established within 1–2 min of applying the pheromone (ipsenol, ipsdienol,cis-verbenol), and that this gradient was nearly constant for 20–95 min after application. The concentration fell rapidly and approximately exponentially between the source and the center of the arena. Turning rate and the number of beetles that reached the source increased, and heading with respect to the source decreased, in the presence of pheromone. Responses of beetles that did and did not reach the source were significantly different, but within each group there were no significant differences among dosages. Turning rate and heading varied little with distance from the source, while walking rate decreased as distance from the release point of the beetles increased. We hypothesize that dosage exerts its major effect on source location by altering the probability that a beetle will enter into orientation behavior and that beetles orienting to sources have similar behaviors even when orienting to a wide range of dosages.