稻纵卷叶螟幼虫颗粒体病毒

稻纵卷叶螟(Cnaphalocrocis medinalis)是我国水稻重要害虫之一。1979年秋,我们在广东省恩平县的晚造水稻田里,发现稻纵卷叶螟幼虫的一种流行性病毒病,死亡率达30—40%,虫口密度大的田块尤多。罹病幼虫表皮常出现黄色斑点,继而体色     

稻纵卷叶螟颗粒体病毒的增殖与持续传播特征

【目的】分析稻纵卷叶螟颗粒体病毒(Cnaphalocrocis medinalis Guenée granulovirus, CnmeGV)在稻纵卷叶螟(Cnaphalocrocis medinalis)体内的增殖动态,明确其持续传播特征,丰富杆状病毒流行病学研究,为CnmeGV制剂的高效应用提供理论支撑。【方法】转录组测序分析幼虫感染CnmeGV 96 h后及羽化成虫中病毒基因的转录水平,建立基于CnmeGV特异基因Cmorf123的定量检测标记,分析CnmeGV在稻纵卷叶螟体内的增殖动态和持续传播特征。【结果】转录组测序分析表明,CnmeGV所有基因都在幼虫体内转录,其中转录水平最高的为乙酰基转移酶基因,但在成虫转录组中未发现病毒基因的转录。建立了CnmeGV定量检测体系,发现病毒在侵染48 h后,基因复制水平稳定;在侵染后的2 d与4 d病毒拷贝数显著增加,侵染4 d后,DNA含83个病毒拷贝/ng。稻纵卷叶螟幼虫感染CnmeGV后,在成虫和卵中未检测到病毒基因的转录,而在蛹中检测到少量的病毒转录本;86.7%以上的蛹和蛹蜕中均检测到病毒DNA,13.3%成虫中检测到病毒DNA,卵和感染后的第二代幼虫也均能检测到病毒DNA,但卵表经处理后未检测到病毒DNA。【结论】CnmeGV感染稻纵卷叶螟4 d内增殖水平逐渐增加并稳定。CnmeGV病毒粒子可以通过成虫经卵表跨代传播,羽化是稻纵卷叶螟清除CnmeGV的主要途径。     

扬州邗江地区稻纵卷叶螟发生动态及影响因素分析

稻纵卷叶螟Cnaphalocrocis medinalis是扬州邗江地区重要的水稻害虫之一,具有远距离迁飞特性,且长期以来给本地区水稻安全生产带来了巨大威胁.为了明确扬州邗江地区稻纵卷叶螟的田间种群动态,本研究通过田间系统调查发现2010-2020年间稻纵卷叶螟四(2)代为害较轻,五(3)代和六(4)代仍是主害代.四(...     

稻纵卷叶螟卵空间分布型及其抽样技术研究

<正> 研究害虫的空间分布型,不仅可以揭示出种群的空间型的特征,而且它对确定资料代换和相应抽样技术以及对提高测报质量和防治技术都有着十分重要的意义。 稻纵卷叶螟Cnaphalocrocis medinalis Guenee为我县稻区主要害虫,近几年来为害有加重的趋势。现行防治指标和确定发生程度均以幼虫数量为依据,但低龄幼虫不易发现,影响其调查准确性。为了确切地掌握田间稻纵卷叶螟的发生量,更好地指导防治,为此,我们在探索以田间落卵量作为确定发生程度和防治指标阈限的     

稻纵卷叶螟也能在稻叶上化蛹

稻纵卷叶螟(Cnaphalocrocis medinalis Gueu.)是水稻和陆稻的主要害虫之一。在一般情况下幼虫老熟后移至稻丛基部、叶鞘中或枯叶鞘内结薄茧化蛹,所以在稻田中很难找到稻纵卷叶螟的蛹。 1963年我在温州梧埏郊区丰产田中发现此虫能在水稻叶片中化蛹。为了进一步搞清这个问题,进行     

纵卷叶螟绒茧蜂对稻纵卷叶螟幼虫的功能反应

在室内测定了纵卷叶螟绒茧蜂Apanteles cypris对稻纵卷叶螟Cnaphalocrocis medinalis幼虫的功能反应和寻找效应.结果表明,纵卷叶螟绒茧蜂对稻纵卷叶螟幼虫的功能反应可用Michaelis-Menten-Ⅱ型功能反应模型Na=AN0/（F+N0）拟合,一头纵卷叶螟绒茧蜂雌蜂在24h内对稻纵卷...     

稻纵卷叶螟中期测报的初步研究

稻纵卷叶螟Cnaphalocrocis medinalis Guenée自六十年代中期上升为全国主要稻区的常发性害虫后,我地为全国稻纵卷叶螟常年成灾县之一。为了更好地指导大面积稻纵卷叶螟防治工作,在距主害代一月前作出虫情预报是必要的。根据作者在黔江县积累的稻纵卷叶螟多年测报资料,采用“平稳时间序列法”或“相关系数法”进行分析,建立稻纵卷叶螟在本地的中期预报模式如下:     

寄主转换对稻纵卷叶螟寄主种群适合度及生命表参数的影响

[目的]稻纵卷叶螟Cnaphalocrocis medinalis是水稻的迁飞性害虫之一,同时也能在玉米上完成世代.本研究旨在探究寄主转换对稻纵卷叶螟寄主种群适合度的影响.[方法]稻纵卷叶螟玉米种群和水稻种群分别取食原寄主和转换寄主,形成取食玉米的稻纵卷叶螟玉米种群、取食水稻的稻纵卷叶螟玉米种群、取食玉米的稻纵卷叶螟水...     

稻纵卷叶螟空间分布型及抽样技术的初步研究

<正> 稻纵卷叶螟Cnaphalocrocis medinalis Gue-née是水稻上的重要害虫。近十多年来,该虫在浙江省大发生频次显著增加,严重影响水稻     

稻纵卷叶螟发生为害与寄主植物间关系的研究进展

稻纵卷叶螟Cnaphalocrocis medinalis(Guenée)是水稻上的重要害虫,严重影响水稻产量和品质。明确稻纵卷叶螟发生为害与寄主植物间的关系是防治稻纵卷叶螟的基础。本文综述了稻纵卷叶螟的寄主植物种类、稻纵卷叶螟的寄主选择性及寄主对稻纵卷叶螟发育适合度的影响,总结了稻纵卷叶螟的发生为害与水稻品种、水稻栽培制度间的关系,以及非生物因素对稻纵卷叶螟的寄主适应性和为害的影响,并对相关研究进行了展望,旨在为稻纵卷叶螟与寄主互作关系的深入研究及其绿色防控提供理论依据。     

杨扇舟蛾颗粒体病毒晚期表达因子的分析

【目的】本研究对杨扇舟蛾颗粒体病毒(Clostera anachoreta granulovirus,Clan GV)的晚期表达因子(Late expression factors,LEFs)进行生物信息学分析,并对Clan GV的lefs与其它杆状病毒的lefs进行对比,对鉴定lef基因和研究Clan GV的感染机制具有重要意义。【方法】使用ORF finder在线程序进行开放阅读框(ORFs)分析,BLASTP程序用于蛋白序列的同源分析,DNAStar和DNAClub生物学软件用于对序列进行处理和分析,采用BLAST在公共数据库中对序列进行比对,Clustal W Version 1.8和Gene Doc 2.7用于多序列的比对和分析,用MEGA 6.06的NJ法进行系统发育分析。【结果】Clan GV基因组包括15个lef基因,分别为ie-1、lef-2、39k、lef-11、p35、p47、lef-1、lef-6、lef-5、lef-4、dnapol、lef-3、lef-9、lef-8和lef-10。Clan GV与云杉枞色卷蛾颗粒体病毒(Choristoneura occidentalis granulovirus,Co GV)、黄地老虎颗粒体病毒(Agrotis segetum granulovirus,As GV)、苹果异形小卷蛾颗粒体病毒(Cryptophlebia leucotreta granulovirus,Cl GV)、马铃薯块茎蛾颗粒体病毒(Phthorimaea operculella granulovirus,Po GV)和苹果蠹蛾颗粒体病毒(Cydia pomonella granulovirus,Cp GV)有着较近的亲缘关系。颗粒体病毒中只有Clan GV和分月扇舟蛾颗粒体病毒含有p35。Clan GV的lef-2的转录方向不同于其它12个颗粒体病毒。γ和δ杆状病毒分别只含有7个和3个Clan GV的lef同源基因。Clan GV的lefs跟其它杆状病毒lefs的相似性较低,其中Clan GV与其它颗粒体病毒间的相似性高于Clan GV与核型多角体病毒间的相似性。Clan GV的lef-2、39k、p35、lef-5、dnapol和lef-9在启动子上游拥有TATA box;p47和lef-1在TATA下游20~40 bp处还有一个CACT基序;lef-11、p35、lef-6、lef-5、lef-3、lef-9、lef-8和lef-10这8个基因有晚期启动子基序TAAG;而p35、lef-5、lef-9和lef-10上游既有TATA又有TAAG基序。【结论】结果为研究杆状病毒的基因功能和感染机制提供了数据基础。     

Genome sequencing and analysis of a granulovirus isolated from the Asiatic rice leafroller,Cnaphalocrocis medinalis

The complete genome of Cnaphalocrocis medinalis granulovirus(CnmeGV) from a serious migratory rice pest, Cnaphalocrocis medinalis(Lepidoptera: Pyralidae), was sequenced using the Roche 454 Genome Sequencer FLX system(GS FLX) with shotgun strategy and assembled by Roche GS De Novo assembler software. Its circular double-stranded genome is 111,246 bp in size with a high A+T content of 64.8% and codes for 118 putative open reading frames(ORFs). It contains 37 conserved baculovirus core ORFs, 13 unique ORFs, 26 ORFs that were found in all Lepidoptera baculoviruses and 42 common ORFs. The analysis of nucleotide sequence repeats revealed that the CnmeGV genome differs from the rest of sequenced GVs by a 23 kb and a 17 kb gene block inversions, and does not contain any typical homologous region(hr) except for a region of non-hr-like sequence. Chitinase and cathepsin genes, which are reported to have major roles in the liquefaction of the hosts, were not found in the CnmeGV genome, which explains why CnmeGV infected insects do not show the phenotype of typical liquefaction. Phylogenetic analysis,based on the 37 core baculovirus genes, indicates that CnmeGV is closely related to Adoxophyes orana granulovirus. The genome analysis would contribute to the functional research of CnmeGV,and would benefit to the utilization of CnmeGV as pest control reagent for rice production.     

Genome of Cnaphalocrocis medinalis Granulovirus,the First Crambidae-Infecting Betabaculovirus Isolated from Rice Leaffolder to Sequenced

Cnaphalocrocis medinalis is a major pest of rice in South and South-East Asia. Insecticides are the major means farmers use for management. A naturally occurring baculovirus, C. medinalis granulovirus (CnmeGV), has been isolated from the larvae and this has the potential for use as microbial agent. Here, we described the complete genome sequence of CnmeGV and compared it to other baculovirus genomes. The genome of CnmeGV is 112,060 base pairs in length, has a G+C content of 35.2%. It contains 133 putative open reading frames (ORFs) of at least 150 nucleotides. A hundred and one (101) of these ORFs are homologous to other baculovirus genes including 37 baculovirus core genes. Thirty-two (32) ORFs are unique to CnmeGV with no homologues detected in the GeneBank and 53 tandem repeats (TRs) with sequence length from 25 to 551 nt intersperse throughout the genome of CnmeGV. Six (6) homologous regions (hrs) were identified interspersed throughout the genome. Hr2 contains 11 imperfect palindromes and a high content of AT sequence (about 73%). The unique ORF28 contains a coiled-coil region and a zinc finger-like domain of 4–50 residues specialized by two C2C2 zinc finger motifs that putatively bound two atoms of zinc. ORF21 encoding a chit-1 protein suggesting a horizontal gene transfer from alphabaculovirus. The putative protein presents two carbohydrate-binding module family 14 (CBM_14) domains rather than other homologues detected from betabaculovirus that only contains one chit-binding region. Gene synteny maps showed the colinearity of sequenced betabaculovirus. Phylogenetic analysis indicated that CnmeGV grouped in the betabaculovirus, with a close relation to AdorGV. The cladogram obtained in this work grouped the 17 complete GV genomes in one monophyletic clade. CnmeGV represents a new crambidae host-isolated virus species from the genus Betabaculovirus and is most closely relative of AdorGV. The analyses and information derived from this study will provide a better understanding of the pathological symptoms caused by this virus and its potential use as a microbial pesticide.     

Molecular and phylogenetic characterization of Spodoptera litura granulovirus

Baculovirus, Spodoptera litura granulovirus (SlGV) was isolated from the infected S. litura larvae, and was characterized. The granule of SlGV was ovoidal shape with an approximate size of 240∼340 nm× 140∼180 nm. Each granule contained one single rod-shape virion with a mean size of 180∼200 nm×20∼40 nm. Restriction endonuclease fragment analysis estimated that the total genome size of SlGV is about 115 kb. Necleotide sequence analysis of the granulin gene showed that the gene encodes 249 amino acids with a predicted molecular mass of 29 kDa. When the phylogenic relationship was analyzed using the nucleotide sequence of the granulin gene, SlGV was most closely related to Trichoplusia ni granulovirus (TnGV) and Xestia c-nigrum granulovirus (XcGV) which belong to Type I granulovirus.     

Identification, characterization and phylogenic analysis of conserved genes within the odvp-6e/odv-e56 gene region of Choristoneura fumiferana granulovirus

The genes that are located within the odvp-6e/odv-e56 region of the Choristoneura fumiferana granulovirus (ChfuGV) were identified by sequencing the 11 kb BamHI restriction fragment on the ChfuGV genome. The global GC content that was calculated from the data obtained from this genomic region was 34.96%. The open-reading frames (ORFs), located within the odvp-6e/odv-e56 region, are presented and compared to the equivalent ORFs that are located at the same region in other GVs. This region is composed of 14 ORFs, including three ORFs that are unique to ChfuGV with no obvious homologues in other baculoviruses as well as eleven ORFs with homologues to granuloviral ORFs, such as granulin, CfORF2, pk-1, ie-1, odv-e18, p49, and odvp-6e/odv-e56. In this study, the conceptual products of seven major conserved ORFs (granulin, CfORF2, IE-1, ODV-E18, p49 and ODVP-6E/ODV-E56) were used in order to construct phylogenetic trees. Our results show that granuloviruses can be grouped in 2 distinct groups as follows: Group I; Choristoneura fumiferana granulovirus (ChfuGV), Cydia pomonella granulovirus (CpGV), Phthorimaea operculella granulovirus (PhopGV), and Adoxophyes orana granulovirus (AoGV). Group II; Xestia c-nigrum granulovirus (XcGV), Plutella xylostella granulovirus (PxGV), and Trichoplusia ni granulovirus (TnGV). The ChfuGV conserved proteins are most closely related to those of CpGV, PhopGV, and AoGV. Comparative studies, performed on gene arrangements within this region of genomes, demonstrated that three GVs from group I maintain similar gene arrangements.     

稻纵卷叶螟肠道细菌群落结构与多样性分析

【目的】为明确水稻主要害虫稻纵卷叶螟Cnaphalocrocis medinalis(Guenée)幼虫肠道细菌的群落结构和多样性。【方法】利用Illumina Mi Seq技术对稻纵卷叶螟4龄幼虫肠道细菌的16S r DNA V3-V4变异区序列进行测序,应用USEARCH和QIIME软件整理和统计样品序列数和操作分类单元(operational taxonomic unit,OTU)数量,分析4龄幼虫肠道细菌的物种组成、丰度和多样性。【结果】稻纵卷叶螟4个数量不同的4龄幼虫样本(1,2,3和5头)共得165 386条reads,在97%相似度下可将其聚类为604个OTUs。总共注释到22个门,43个纲,82个目,142个科,204个属,244个种。其中在门水平上,主要优势菌为变形菌门(Proteobacteria)(相对丰度26%~34%)和放线菌门(Actinobacteria)(23%~32%);在纲水平上,主要优势菌为放线菌纲(Actinobacteria)(相对丰度23%~32%)、酸杆菌纲(Acidobacteria)(9%~11%)、α-变形菌纲(Alphaproteobacteria)(10%~13%)、β-变形菌纲(Betaproteobacteria)(6%~8%)和γ-变形菌纲(Gammaproteobacteria)(6%~12%);在科水平上,共有优势菌为类诺卡氏菌科(Nocardioidaceae)、丛毛单胞菌科(Comamonadaceae)、黄单胞菌科(Xanthomonadaceae)、鞘脂单胞菌科(Sphingomonadaceae)和芽单胞菌科(Gemmatimonadaceae)等。在属水平上,4个样本前5位优势属中,类诺卡氏属Nocardioides和鞘脂单胞菌Sphingomonas为共有优势属。稻纵卷叶螟肠道细菌Simpson指数、Shannon指数、Ace指数和Chao指数分别为0.16~0.65,0.94~3.22,212~488和210~490。【结论】稻纵卷叶螟幼虫肠道细菌多样性比较丰富,个体间微生物群落结构和多样性有差异。不同数量样本数据与总体数据有助于综合反映稻纵卷叶螟种群肠道微生物状况。本研究结果为进一步研究稻纵卷叶螟肠道微生物的功能及其在防治中的应用奠定了基础。     

广西兴安转Bt水稻大田两迁害虫发生动态

以转Bt水稻华恢1号(Cry1Ac/ CryAb融合基因型,简称HH1)及其对照亲本明恢63(简称MH63)稻田两迁害虫稻纵卷叶螟和白背飞虱为研究对象,系统研究转基因抗虫水稻种植下两迁害虫的发生规律及其致害力差异.结果表明:转Bt水稻及其对照亲本上稻纵卷叶螟的落卵量和幼虫发生量无显著差异,但转Bt水稻的卷叶株率和卷叶率都显著低于对照亲本.表明转Bt水稻对靶标害虫稻纵卷叶螟具有较高抗性.转Bt水稻及对照亲本上白背飞虱若虫、成虫及整个种群的发生动态差异不显著,且转Bt水稻对长翅型和短翅型成虫的种群发生影响也不显著.白背飞虱发生高峰期,转Bt水稻上若虫及短翅型成虫发生量均明显高于对照亲本;相反,转Bt水稻上长翅型成虫发生量明显低于对照亲本,且水稻生育后期长翅型成虫雌性比明显低于对照亲本.转Bt水稻大面积商业化种植下其非靶标害虫白背飞虱的发生危害变得更为复杂.     

小菜蛾颗粒体病毒晚期表达因子基因的功能分析

小菜蛾颗粒体病毒(Plutella xylostella granulovirus,PlxyGV)基因组含有15个杆状病毒晚期表达因子(Lateexpression factor,lef)基因同源物。PlxyGV的14个lef基因(不包括ie-0)预期编码产物与苜蓿银纹夜蛾核多角体病毒(Autographa californica multicapsid nucleopolyhedrovirus,AcMNPV)LEF蛋白的序列相似度为13%～53%。其中,LEF-8、LEF-9和P47在两种病毒之间的相似度较高,分别为49%、53%和46%。为了研究不同杆状病毒种间lef基因的功能相关性,验证PlxyGVlef基因的功能,本文利用AcMNPV的一个瞬时表达实验系统测试PlxyGVlef基因在Sf9细胞中激活AcMNPV晚期启动子控制的报告基因表达的能力。实验结果显示,在其它AcMNPVlef基因都存在的情况下,PlxyGVlef-2能够部分替代AcMNPVlef-2的活性。序列对比结果显示Plx-yGV LEF-2的C端末比其它GV和鳞翅目NPV的LEF-2分别多出约100aa和70aa。