Nosema bombycis, the causative agent of pébrine disease, is a major pathogen of the economically important silkworm Bombyx mori, resulting in substantial losses in sericulture. While conventional control strategies offer limited efficacy, symbiont-mediated RNA interference (RNAi) has emerged as a sustainable and targeted strategy for disease control. This study investigates the role of gut microbiota in host defense and evaluates the potential of engineered Enterococcus faecalis to inhibit N. bombycis proliferation by disrupting its antioxidant systems. Germ-free and mono-colonized silkworm models were established to assess the effects of core gut symbionts on N. bombycis infection. Among the tested gut microbiota, E. faecalis demonstrated unique protective properties, reducing N. bombycis gene copy number by 83.97% compared to germ-free controls. This protection was associated with the significant upregulation of host ROS-generating enzymes and sustained elevation of gut ROS levels. Accordingly, N. bombycis infection triggers a substantial reorganization of thioredoxin and glutathione systems to counteract host-derived oxidative stress. Nanoparticle-mediated RNAi targeting microsporidian γ-glutamylcysteine synthetase (γ GCS) and thioredoxin reductase (TrxR) genes significantly reduced N. bombycis gene copy number, confirming the critical role of antioxidant mechanisms in N. bombycis invasion. Finally, the engineered E. faecalis successfully colonized the silkworm gut, where it delivered dsRNA targeting the microsporidian redox system to induce RNAi-mediated gene silencing and significantly suppress N. bombycis proliferation. Our findings broaden the understanding of microbial defense mechanisms and offer a sustainable, symbiont-based RNAi strategy for inhibiting microsporidian infection in silkworm.

Introduction:The lactic acid bacteria (LAB) has shown great potential as a sustainable solution to support agriculture through its plant-growth-promoting and biocontrol activities. However, their efficacy as bioinoculants is limited by unpredictable colonization in natural conditions. Methods:The bacterial strain LP0308, identified as Lactobacillus plantarum (LP0308) based on 16S rRNA sequence analysis, was obtained from rhizosphere soil. The features and colonization strategies of LP0308 were characterized through genome sequencing, tomato seed germination assays, pot experiments, and measurements of soil physicochemical properties and enzyme activities. Results:LP0308 was introduced into the soil of tomato, and it could stably persist and proliferate for a long-term (0-20 days), as confirmed by colony-forming unit (CFU), quantitative real-time PCR (RT-qPCR), and fluorescence in situ hybridization (FISH) analyses. Further characterization revealed that LP0308 altered the microbial composition of the rhizosphere soil and significantly increased the abundance of Bacillus and potentially pathogenic microorganism. Further analyses revealed that LP0308 altered the rhizosphere soil microbial community, significantly increasing the abundance of Bacillus spp. while decreasing the potential pathogenic microorganisms, such as Ralstonia solanacearum and Fusarium oxysporum. In addition, the successful colonization of LP0308 led to drastically increased expression of encoding biofilm (vpsI1, vpsI2, vpsC, and vpsI3), immune modulation (pbpG, kdtB, and wbpL), and antimicrobial activity gene (farB). L. plantarum strain LP0308 was confirmed as a possible plant growth-promoting rhizobacteria (PGPR), which significantly promoted bud length, plant height, primary root length, root fresh weight, and whole-seedling fresh weight. Additionally, application of LP0308 markedly improved soil nutrient availability and stimulated key enzymatic activities. Discussion:Together, our findings suggest the LP0308 as a potential target for developing more effective bioinoculants for sustainable agriculture.

The microsporidian Nosema bombycis is an obligate intracellular fungal-related parasites of the Bombyx mori, causing the epidemic disease Pebrine and extensive economic losses in the agricultural and sericulture industry. Enterococcus has emerged as one of the predominant gut microorganisms of the major model organism, Bombyx mori. However, the potential interactions mechanism between B. mori, N. bombycis and Enterococcus have not been well demonstrated. To address this gap, we used an insect model, silkworm to examine the potential mechanism of the natural symbiotic bacterium Enterococcus faecalis LX10 drives B. mori refractoriness to N. bombycis infection. E. faecalis LX10 was isolated from the gut of healthy silkworms, and its inhibitory activity against N. bombycis was evaluated at both the cellular and individual levels using posttranslational modifications, gene and protein expression analysis, transfected cells, and in vitro immunofluorescence. We demonstrated that enterococcin (EntLX), the first antimicrobial protein family in gut commensal bacterium Enterococcus faecalis LX10 of B. mori, contributes to defending against N. bombycis infection resistance depends on the enzyme gelatinase (GelE), disulfide bond and disulfide bond formation proteinA (DsbA). The EntLX protein, abundantly expressed in transgenic BmN cells and gut organs(gut epithelium, peritrophic membrane and contents), can reduce the infection rate of cells and alleviate intestinal damage caused by N. bombycis infection. After simultaneous vaccination with E. faecalis LX10 and N. bombycis, the differentially key metabolites, physiological characteristics(larval mass), or economic traits(cocoon length, cocoon width, whole-cocoon weight, cocoon shell weight, pupation rate and adult emergence rate) showed a certain degrees of recovery and correction compared with those of single N. bombycis inoculation at the individual level. This study advances the understanding of the anti-microsporidia activity of enterococci and paves the way for the expression of these molecules as antifungal agents via the genetic transformation of Enterococcus symbionts from disease-transmitting insects. Not applicable.

In order to develop the plant-derived active substance vanillin, 2-hydroxypropyl-I3-cyclodextrin was used to encapsulate vanillin, and a chitosan-based edible coating: vanillin-HPI3CD/CH was developed for chicken preservation. First, vanillin was inserted into the internal cavity of HPI3CD through an ultrasonic-assisted method to form vanillin/HPI3CD-IC. The inclusion complex of vanillin/HPI3CD-IC was demonstrated to be successfully synthesized by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Through antibacterial testing, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), it was verified that inclusion improved the thermal stability of vanillin while retaining the antibacterial effect of vanillin. The release of vanillin from encapsulated particle exhibited pH-dependent slow controlled release, and can described by First order model. Subsequently, vanillin/ HPI3CD-IC was compounded with chitosan through a composite film-forming method to prepare an edible coating: vanillin-HPI3CD/CH. By characterizing the performance of vanillin-HPI3CD/CH, it was found that the addition of vanillin/HPI3CD-IC can improve the stability, isolation hydrophobicity and antibacterial performance of the plastic wrap. Finally, vanillin-HPI3CD/CH was applied to chicken preservation, and it was found that vanillin-HPI3CD/CH could effectively extend the shelf life of chicken and maintain sensory quality by slowing down the rise in pH, preventing the proliferation of microorganisms, and inhibiting lipid oxidation. In summary, vanillin-HPI3CD/CH is an edible coating with superior performance and a promising packaging material for chicken freshness preservation.

BACKGROUND The widespread use of chemical insecticides has resulted in the development of resistance in German cockroaches worldwide, and biopesticides based on entomopathogenic fungi as active ingredients have become a promising alternative strategy. Resistance can change many of the physiological and biochemical characteristics of insect pests, such as cuticle thickness, detoxification enzyme activity, and even intestinal flora composition. Thus, potential interactions between pathogenic fungi and insecticide resistance may lead to unpredictable changes in pest susceptibility to fungi. RESULTS Beta-cypermethrin-resistant German cockroaches were more susceptible to infection with the fungus Metarhizium anisopliae regardless of age and sex. Histopathological results showed that the infection of resistant strains (R) by M. anisopliae was visibly faster than that of susceptible strains (S). The gut microbiota of the S strain indicated a stronger ability to inhibit fungi in vitro. The abundance of Parabacteroides, Lachnoclostridium, and Tyzzerella_3 decreased significantly in the R strain, and most demonstrated the ability to regulate glucose and lipid metabolism, and antifungal infections. The expression levels of Akirin, BgTPS and BgPo genes in the R strain were significantly lower than those in the S strain, while BgChi and CYP4G19 gene expression were significantly higher. The mortality of cockroaches infected with M. anisopliae decreased to varying degrees after RNA interference, reflecting the role of these genes in antifungal infection. CONCLUSIONS Results confirmed that insecticide resistance may enhance cockroach susceptibility to fungi by altering intestinal flora and gene expression. Fungal biopesticides have high utilization value in pest control and insecticide resistance management strategies. This article is protected by copyright. All rights reserved.

AbstractBACKGROUNDMicrosporidia, a group of obligate intracellular fungal‐related parasites, have been used as efficient biocontrol agents for agriculture and forestry pests due to their host specificity and transovarial transmission. They mainly infect insect pests through the intestinal tract, but the interactions between microsporidia and the gut microbiota of the host have not been well demonstrated.RESULTSBased on the microsporidia–Bombyx mori model, we report that the susceptibility of silkworms to exposure to the microsporidium Nosema bombycis was both dose and time dependent. Comparative analyses of the silkworm gut microbiome revealed substantially increased abundance of Enterococcus belonging to Firmicutes after N. bombycis infection. Furthermore, a bacterial strain (LX10) was obtained from the gut of B. mori and identified as Enterococcus faecalis based on 16S rRNA sequence analysis. E. faecalis LX10 reduced the N. bombycis spore germination rate and the infection efficiency in vitro and in vivo, as confirmed by bioassay tests and histopathological analyses. In addition, after simultaneous oral feeding with E. faecalis LX10 and N. bombycis, gene (Akirin, Cecropin A, Mesh, Ssk, DUOX and NOS) expression, hydrogen peroxide and nitric oxide levels, and glutathione S‐transferase (GST) activity showed different degrees of recovery and correction compared with those under N. bombycis infection alone. Finally, the enterococcin LX protein was identified from sterile LX10 fermentation liquid based on liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis.CONCLUSIONAltogether, the results revealed that E. faecalis LX10 with anti‐N. bombycis activity might play an important role in protecting silkworms from microsporidia. Removal of these specific commensal bacteria with antibiotics and utilization of transgenic symbiotic systems may effectively improve the biocontrol value of microsporidia. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The complex gut microbiome is a malleable microbial community that can undergo remodeling in response to many factors, including the gut environment and microbial properties. Enterococcus has emerged as one of the predominant gut commensal bacterial and plays a fundamental role in the host physiology and health of the major economic agricultural insect, Bombyx mori. Although extensive research on gut structure and microbiome diversity has been carried out, how these microbial consortia are established in multifarious niches within the gut has not been well characterized to date. Here, an Enterococcus species that was stably associated with its host, the model organism B. mori, was identified in the larval gut. GFP-tagged E. faecalis LX10 was constructed as a model bacterium to track the colonization mechanism in the intestine of B. mori. The results revealed that the minimum and optimum colonization results were obtained by feeding at doses of 10(5) CFU/silkworm and 10(7) CFU/silkworm, respectively, as confirmed by bioassays and fluorescence-activated cell sorting analyses (FACS). Furthermore, a comprehensive genome-wide exploration of signal sequences provided insight into the relevant colonization properties of E. faecalis LX10. E. faecalis LX10 grew well under alkaline conditions and stably reduced the intestinal pH through lactic acid production. Additionally, the genomic features responsible for lactic acid fermentation were characterized. We further expressed and purified E. faecalis bacteriocin and found that it was particularly effective against other gut bacteria, including Enterococcus casselifavus, Enterococcus mundtii, Serratia marcescens, Bacillus amyloliquefaciens, and Escherichia coli. In addition, the successful colonization of E. faecalis LX10 led to drastically increased expression of all adhesion genes (znuA, lepB, hssA, adhE, EbpA, and Lap), defense genes (cspp, tagF, and esp), regulation gene (BfmRS), secretion gene (prkC) and immune evasion genes (patA and patB), while the expression of iron acquisition genes (ddpD and metN) was largely unchanged or decreased. This work establishes an unprecedented conceptual model for understanding B. mori-gut microbiota interactions in an ecological context. Moreover, these results shed light on the molecular mechanisms of gut microbiota proliferation and colonization in the intestinal tract of this insect.

Lepidopteran insects are one of the most widespread and speciose lineages on Earth, with many common pests and beneficial insect species. The evolutionary success of their diversification depends on the essential functions of gut microorganisms. This diverse gut microbiota of lepidopteran insects provides benefits in nutrition and reproductive regulation and plays an important role in the defence against pathogens, enhancing host immune homeostasis. In addition, gut symbionts have shown promising applications in the development of novel tools for biological control, biodegradation of waste, and blocking the transmission of insect-borne diseases. Even though most microbial symbionts are unculturable, the rapidly expanding catalogue of microbial genomes and the application of modern genetic techniques offer a viable alternative for studying these microbes. Here, we discuss the gut structure and microbial diversity of lepidopteran insects, as well as advances in the understanding of symbiotic relationships and interactions between hosts and symbionts. Furthermore, we provide an overview of the function of the gut microbiota, including in host nutrition and metabolism, immune defence, and potential mechanisms of detoxification. Due to the relevance of lepidopteran pests in agricultural production, it can be expected that the research on the interactions between lepidopteran insects and their gut microbiota will be used for biological pest control and protection of beneficial insects in the future.

Mulberry sclerotial disease is a devastating disease in mulberry production. In order to understand the existent situation of pathogens and their microecology in the soil of the mulberry field, we collected the soil samples from mulberry fields in four plots of different regions in Zhejiang Province [namely Deqing County (DQ), Changxing County (CX), Jinhua Duohu Residential District (JD) and Jiangdong Town (JJ)]. Among them, CX mulberries were cultivated in greenhouse, and the others were cultivated in open field. The experiment took one plot in Sichuan Province as a control (CK), which was rarely or never found the sclerotial disease. Then, we identified the soil fungi and bacteria through high-throughput sequencing of internal transcribed spacer (ITS) and 16S rRNA. The results showed that the relative abundance (RA) of genus Ciboria in the mulberry fields of DQ, JJ and JD were 28.84%, 60.17%, and 70.15%, respectively. No diseased fruit of mulberry sclerotinia was found in CX and CK fields, and the relative abundance of Ciboria was 0.02% and 0.06‱, respectively. The main microorganisms in CX field were Mortierella, Chaetomium, and Humicola, with the relative abundance of 36.46%, 21.59%, and 15.93%, respectively; the main microorganisms in CK field were Penicillium, Fusarium, and Fusicolla, and their relative abundances were 24.05%, 15.35%, and 9.75%, respectively. Among the bacteria, Pseudomonas was the only genus identified in all five field samples, and the highest relative abundance of Pseudomonas was found in the JJ field (but only 6.81%), highlighting a rich bacterial diversity. Collectively, the relative abundance of the genus Ciboria and the diversity of fungi and bacteria reveal the complex relationship between the relative abundance of Ciboria and the soil microecology in mulberry fields. It also further implies the possibility of preventing and controlling mulberry sclerotial disease by changing the soil microecological structure.

Aims L-tryptophan is an essential aromatic amino acid for the growth and development of animals. Studies about enteric L-tryptophan-producing bacteria are scarce. In this report, we characterized the probiotic potential of Enterococcus casseliflavus ECB140, focusing on its L-tryptophan production abilities. Methods and results ECB140 strain was isolated from the silkworm gut and can survive under strong alkaline environmental conditions. Bacterial colonization traits (motility and biofilm) were examined and showed that only ECB140 produced flagellum and strong biofilms compared with other Enterococcus strains. Comparative genome sequence analyses showed that only ECB140 possessed a complete route for L-tryptophan synthesis among all 15 strains. High-performance liquid chromatography and qRT-PCR confirmed the capability of ECB140 to produce L-tryptophan. Besides, the genome also contains the biosynthesis pathways of several other essential amino acids, such as phenylalanine, threonine, valine, leucine, isoleucine and lysine. These results indicate that ECB140 has the ability to survive passage through the gut and could act as a candidate probiotic. Conclusions The study describes a novel, natural silkworm gut symbiont capable of producing L-tryptophan. Enterococcus casseliflavus ECB140 physical and genomic attributes offer possibilities for its colonization and provide L-tryptophan for lepidopteran insects.

为探明真菌繁殖对家蚕人工饲料酸碱度的影响,采用常规分离纯化技术,从人工饲料育养蚕环境的蚕座上获得1株可碱化饲料的真菌,经形态学和ITS序列鉴定,为库德里阿兹威氏毕赤酵母(Pichia kudravzevii).该菌株接种至家蚕人工饲料,使饲料pH在5 d内由初始值上升至7.54;接种至不同pH和葡萄糖含量的液体YPD中,其能适应繁殖基质pH的变化,碱化培养基质,使酸性培养基pH在6h内升高,在24 h内上升到7.86(pH 5.00)和8.26(pH 6.00);培养基质中葡萄糖含量影响碱化,低浓度葡萄糖(＜0.6％)培养基碱化现象明显,高浓度葡萄糖(＞1.2％)培养基碱化现象消失.菌株接种至pH为3.00、5.00和7.00的不含葡萄糖YPD培养基中培养不同时间,对环境中氨气释放量、碱化相关基因表达及谷氨酸脱氢酶活性进行研究,结果表明,与添加2％葡萄糖相比,固体培养基中氨气释放量在培养24 h(pH 5.00)和4 h(pH 7.00)时极显著上升(P＜0.01),随后持续升至最高值280 mg/m3(pH 7.00);谷氨酸脱氢酶活性逐渐升高,在12 h(pH 5.00)和24 h(pH 7.00)时达到最大值53.84 U/mL和24.84 U/mL,极显著高于对照组(P＜0.01);液体培养基中碱化相关基因GDH2、DUR1,2和ATO3表达水平呈先升高后降低趋势,GDH2转录水平分别在8 h(pH 3.00)、4 h(pH 5.00)和8 h(pH 7.00)上调最高,极显著高于对照组(P＜0.01),随后下降,ATO3转录水平分别在4 h(pH 3.00)、12 h(pH 5.00)和8 h(pH 7.00)显著上调,且最高(P＜0.05),然后下降,DUR1,2转录水平均在8 h极显著高于对照组(P＜0.01).添加抗霉素A,碱化程度下降甚至消失.该研究可为解明家蚕人工饲料的保鲜机制及研发保鲜技术提供参考.

家蚕起源和养蚕起始是两个不同概念或范畴的问题.本文从生物学和文献学的视角论述结果为:家蚕起源于单一地域的可能性更大,时间可能是4000万年～9300万年,是从"古家蚕"自然演化而来;殷墟、西阴村和钱山漾遗址实物考古中的发现是养蚕相关的三个典型代表,养蚕起始时间由此被定格为约5000年前;成书于周朝的《诗经》和战国的《管子》等古典籍,则记载了我国人民在3000年前栽桑养蚕的生产场景;西汉晚期的《氾胜之书》和东汉崔寔的《四民月令》,则介绍了所在历史时期我国不同区域的养蚕技术及蚕丝产品的不同及生产规模.文化概念的养蚕与中华文明的诞生同步,养蚕产业的形成至少有3000年的历史.

Organophosphate insecticides that are heavily used in agriculture for pest control have caused growing environmental problems and public health concerns worldwide. Ironically, insecticide resistance develops quickly in major lepidopteran pests, partially via their microbial symbionts. To investigate the possible mechanisms by which the microbiota confers insecticide resistance to Lepidoptera, the model organism silkworm Bombyx mori (Lepidoptera: Bombycidae) was fed different antibiotics to induce gut dysbiosis (microbiota imbalance). Larvae treated with polymyxin showed a significantly lower survival rate when exposed to chlorpyrifos. Through high-throughput sequencing, we found that the abundances of Stenotrophomonas and Enterococcus spp. changed substantially after treatment. To assess the roles played by these two groups of bacteria in chlorpyrifos resistance, a germ-free (GF) silkworm rearing protocol was established to avoid the influence of natural microbiota and antibiotics. Monoassociation of GF silkworms with Stenotrophomonas enhanced host resistance to chlorpyrifos, but not in Enterococcus-fed larvae, consistent with larval detoxification activity. GC-μECD detection of chlorpyrifos residues in feces indicated that neither Stenotrophomonas nor Enterococcus degraded chlorpyrifos directly in the gut. However, gut metabolomics analysis revealed a highly species-specific pattern, with higher levels of essential amino acid produced in the gut of silkworm larvae monoassociated with Stenotrophomonas. This critical nutrient provisioning significantly increased host fitness and thereby allowed larvae to circumvent the deleterious effects of these toxic chemicals more efficiently. Altogether, our study not only suggests a new mechanism for insecticide resistance in notorious lepidopteran pests but also provides a useful template for investigating the interplay between host and gut bacteria in complex environmental systems.

Mulberry (Morus) is an economically important woody tree that is suitable for use in sericulture as forage and in medicine. However, this broad-leaved tree is facing multiple threats ranging from phytopathogens to insect pests. Here, a Gram-positive, endospore-forming bacterium (ZJU1) was frequently isolated from healthy mulberry plants by screening for foliar endophytes showing antagonism against pathogens and pests. Whole-genome sequencing and annotation resulted in a genome size of 4.06 Mb and classified the bacterium as a novel strain of Bacillus amyloliquefaciens that has rarely been identified from tree leaves. An integrative approach combining traditional natural product chemistry, activity bioassays, and high-resolution mass spectrometry confirmed that strain ZJU1 uses a blend of antimicrobials including peptides and volatile organic compounds to oppose Botrytis cinerea, a major phytopathogenic fungus causing mulberry gray mold disease. We showed that the inoculation of endophyte-free plants with ZJU1 significantly decreased both leaf necrosis and mortality under field conditions. In addition to the direct interactions of endophytes with foliar pathogens, in planta studies suggested that the inoculation of endophytes also induced plant systemic defense, including high expression levels of mulberry disease resistance genes. Moreover, when applied to the generalist herbivore Spodoptera litura, ZJU1 was sufficient to reduce the pest survival rate below 50%. A previously undiscovered crystal toxin (Cry10Aa) could contribute to this insecticidal effect against notorious lepidopteran pests. These unique traits clearly demonstrate that B. amyloliquefaciens ZJU1 is promising for the development of successful strategies for biocontrol applications. The search for new plant-beneficial microbes and engineering microbiomes is therefore of great significance for sustainably improving plant performance.

为了解散卵一代杂交蚕种的均匀性,对桐乡蚕业有限公司生产的10批华康2号和4批秋丰x白玉散卵不同后期处理(常规与混匀处理)或不同取样类型(成品前和笼内)的克卵粒数进行了调查.结果表明:华康2号的克卵粒数极显著多于秋丰x白玉(P=0.001);克卵粒数极差值的显著性比较中,在样点间华康2号生产批极显著大于秋丰x白玉(P=0.000),在生产批间未见显著差异(P=0.623);华康2号和秋丰x白玉笼样卵、常规卵和混匀卵不同批合计抽样点克卵粒数极差值的比较均未见显著差异,但有3个批笼样卵的批内出现显著差异(P=0.000、0.048和0.013);对2个生产批蚕种样点内克卵粒数观察值增加后的极差值比较发现,测定数增加到15个和20个时,1个批出现显著差异(P=0.033和0.025).由此得出初步结论:批内的常规卵和混匀卵具有较好的均匀性,笼样卵的均匀性较差.

为更加有效地评价蚕品种对家蚕核型多角体病毒(Bombyx mori nuclear polyhedrosis virus,BmNPV)病的抗性,采用Reed-Muench法对69个(次)蚕品种的BmNPV多角体的半数致死浓度(LC50)进行了测定.结果 证实,同一蚕品种在相同实验室的不同测定期别或同期试验,以及不同实验室的数据间存在差异.为减少这种蚕品种抗性评价中的困惑,通过不同数量参照蚕品种LC50值校正待测蚕品种LC50值的比较,提出以2对常用蚕品种正反交为参照的抗性指数评价方法,提高不同来源LC50测定数据间的可比性,以期为新品种的育成和新品种的推广提供参考.

为了进一步提升桑果品质,迎合大众休闲体验的需要,以果桑大10品种为对象,并以常规大棚非棚架栽培(以下简称常规栽培)为对照进行了果桑棚架立体栽培(以下简称棚架栽培)试验.结果 表明:棚架栽培的果桑树体生长更为迅速,棚架栽培的果桑由于栽培密度较为稀疏(4.00 m×4.00 m),前2年产量会低于常规栽培,第3年产量与常规栽培相当,但棚架栽培的果桑桑果采摘持续时间较常规栽培延长约20 d,桑果单果质量和可溶性固形物含量显著高于常规栽培,通过修剪控制棚架栽培果桑结果母枝数量,综合考虑产量及品质认为,每株留90根结果母枝为最佳.棚架栽培能使果桑枝条均匀分布于棚架之上,可提高果桑枝条的光照和通风条件,提升桑果的品质,且棚架栽培果桑相对于常规栽培果桑栽培密度较低,不但能节省种苗且棚架下面空间充裕,方便采果和管理.

BACKGROUND:Many insect pests rely on microbial symbionts to obtain nutrients or for defence, thereby allowing them to exploit novel food sources and degrade environmental xenobiotics, including pesticides. Although Lepidoptera is one of the most diverse insect taxa and includes important agricultural pests, lepidopteran microbiotas, particularly functional traits, have not been studied widely. Here, we provide a comprehensive characterization of the gut microbiota across multiple mulberry-feeding lepidopteran species, resolving both community structure and metabolic potential. RESULTS:Our results indicate abundant bacteria inside the gut of larval Lepidoptera. However, even though they were fed the same diet, the structures of the bacterial communities differed in four major mulberry pest species, suggesting host-specific effects on microbial associations. Community-level metabolic reconstructions further showed that although taxonomic composition varied greatly, carbohydrate and amino acid metabolism and membrane transporter were key functional capabilities of the gut bacteria in all samples, which may play basic roles in the larval gut. In addition, principal coordinate analysis (PCoA) of gut bacterial-predicted gene ontologies revealed specialized features of the microbiota associated with these mulberry pests, which were divided into two distinct clusters (macrolepidopterans and microlepidopterans). This pattern became even more prominent when further Lepidoptera species were involved. CONCLUSIONS:A suite of gut microbiota metabolic functions significantly correlated with larval size; the metabolism of terpenoids and polyketides, xenobiotics biodegradation and metabolism were specifically enriched in large species, while small larvae had enhanced nucleotide metabolism. Our report paves the way for uncovering the correlation between host phenotype and microbial symbiosis in this notorious insect pest group. © 2019 Society of Chemical Industry.

Lepidoptera (butterflies and moths) is a major insect order including important pollinators and agricultural pests, however their microbiomes are little studied. Here, using next-generation sequencing (NGS)-based shotgun metagenomics, we characterize both the biodiversity and functional potential of gut microbiota of a lepidopteran model insect, the silkworm Bombyx mori . Two metagenomes, including the standard inbred strain Dazao (P50) and an improved hybrid strain Qiufeng × Baiyu (QB) widely used in commercial silk production, were generated, containing 45,505,084 and 69,127,002 raw reads, respectively. Taxonomic analysis revealed that a total of 663 bacterial species were identified in P50 silkworms, while 322 unique species in QB silkworms. Notably, Enterobacter , Acinetobacter and Enterococcus were dominated in both strains. The further functional annotation was performed by both BlastP and MG-RAST against various databases including Nr, COG, KEGG, CAZy and SignalP, which revealed >5 × 10 6 protein-coding genes. These datasets not only provide first insights into all bacterial genes in silkworm guts, but also help to generate hypotheses for subsequently testing functional traits of gut microbiota in an important insect group.

微孢子虫广泛存在于鳞翅目昆虫中,是一类重要的病原微生物.微孢子虫病一方面影响野外昆虫种群的自然平衡,另一方面对家蚕、柞蚕等经济和资源昆虫造成了严重的危害.微孢子虫分子生物学研究基础相对薄弱,再加上微孢子虫表面坚厚的孢壁,无疑增加了研究难度.随着核酸、蛋白质等生物大分子分离制备方法和高通量测序技术的不断更新发展,基于各种组学(Omics)研究微孢子虫的工作方兴未艾,并且有了一些重要的发现.本文综述了微孢子虫与鳞翅目昆虫寄主的相互作用及寄生于鳞翅目昆虫的病原微孢子虫基因组、转录组和蛋白质组进展情况,以期为微孢子虫的深入研究提供参考.这些昆虫微生物研究将为鳞翅目害虫生物防治提供新的思路,并对家蚕等经济昆虫微粒子病的诊断、防控及治疗产生积极影响.