一种侵染薇甘菊的中国胜红蓟黄脉病毒DNA-A基因组特征及重组分析

为明确采集自我国广西壮族自治区玉林市博白县的疑似为双生病毒侵染并表现叶片黄脉症状薇甘菊的病原物及其基因组分子特征,利用双生病毒DNA-A通用引物SPG1/SPG2和特异性引物WGJ-F/WGJ-R扩增获得病毒基因组,利用β卫星通用引物检测卫星病毒,使用Vector NTI Advance 11.5.1软件进行序列拼接,运用MEGA 7.0和RDP 3.44软件进行系统发育树的构建和重组分析。结果表明：引起薇甘菊叶片黄脉症状的病原物为中国胜红蓟黄脉病毒（Ageratum yellow vein China virus,AYVCNV）,该分离物命名为AYVCNV_WGJ,GenBank登录号为MK880139,但未扩增得到β卫星。该病毒DNA-A基因组全长为2 755 bp,含有6个开放阅读框。AYVCNV-WGJ分离物与AYVCNV鳢肠Eclipta prostrata分离物（GenBank登录号MN218667）的核苷酸序列同源性最高,为90.1%,其中AC4编码的蛋白变异较大。重组结果分析显示AYVCNV_WGJ分离物是由AYVCNV-Tomato分离物（GenBank登录号KU954388）和1个未知病毒（GenBank登录号EU487047）重组得到,重组区域为其基因组2 046~2 612 bp区域。     

广西胜红蓟黄脉病样中发现多种菜豆金色花叶病毒属的病毒

 双生病毒科(Geminiviridae)病毒是一组植物单链DNA病毒,它的特点是病毒粒子形态为孪生颗粒状。双生病毒分为菜豆金色花叶病毒属(Begomovirus)、甜菜曲顶病毒属(Curtovirus)、玉米线条病毒属(Mastrevirus)和番茄伪曲顶病毒属(Topocuvirus)^[1]。     

在中国广东侵染胜红蓟的中国胜红蓟黄脉病毒的鉴定和全基因组分析

2022年9月在广东省罗定市发现了叶片表现为黄色网状症状的胜红蓟病株。为了明确胜红蓟叶片的黄脉症状是否由双生病毒感染引起, 本研究使用检测双生病毒的简并引物PA/PB进行PCR扩增, 获得约500 bp的片段。根据该序列设计特异性引物扩增并且克隆得到了病毒DNA-A的全基因组序列。通过BLAST比对发现, 获得的DNA-A与中国胜红蓟黄脉病毒(ageratum yellow vein China virus, AYVCNV)海南分离物(OQ421190)的DNA-A的相似性最高, 相似度为98.11%。系统进化树分析显示, 获得的病毒DNA-A与海南分离物(OQ421190)在同一分支, 说明具有较近的亲缘关系。以上研究结果表明侵染胜红蓟的病毒是AYVCNV的分离物。这是关于AYVCNV在广东地区侵染胜红蓟的首次报道, 可为当地病毒病的防控提供参考。     

胜红蓟青枯病病原鉴定及其生物学特性

胜红蓟青枯病是我国发生的一种新病害。为了明确引起胜红蓟青枯病的病原,对分离自广东的胜红蓟青枯病菌的菌落形态、16S rDNA序列、碳水化合物利用、致病性及演化型等进行了分析。在含1% 2,3,5-氯化三苯基四氮唑选择性培养基平板上,病原菌的菌落呈近圆形或梭形,隆起,中间粉红色,周围乳白色。应用细菌通用引物27f和1541r扩增16S rDNA,Ac-YcSj-11-1~Ac-YcSj-11-10 10个菌株的16S rDNA近全长均为1 421 bp,且与茄科雷尔氏菌Ralstonia solanacearum GMI1000 16S rDNA的同源率为100%。该病原菌可以利用麦芽糖、乳糖、纤维二糖、山梨醇、甘露醇和卫矛醇等6种碳水化合物,并可侵染姜、沙姜、番茄,弱侵染茄子、辣椒。10个菌株均可同时扩增得到144 bp的演化型Ⅰ特异带和280 bp的茄科雷尔氏菌特异带。研究表明,引起广东胜红蓟青枯病的病原菌为茄科雷尔氏菌R.solanacearum,且属于4号生理小种、生化变种Ⅲ和演化型Ⅰ（亚洲组）。     

广州地区胜红蓟物候学观察与调查研究

目前还没有对胜红蓟生活史进行系统研究的报告,本实验主要调查胜红蓟在广州野外生境的生长发育情况,试图为其生物学特性研究和控制对策的制订提供有价值的依据。实验采用定点定株调查和普查相结合,观察记录出苗期、营养生长期、开花期、结实期和枯黄期等。研究表明,胜红蓟在广州这个温暖湿润的地方任何季节都能生长繁殖。胜红蓟在生育期间遇不利生长环境,生育期会自动缩短,植株能尽早开花结实。     

侵染苣荬菜的中国胜红蓟黄脉病毒及伴随的卫星基因组结构特征

杂草是菜豆金色花叶病毒属病毒的重要中间寄主,常富集多种该属病毒及其卫星病毒。2014年,在云南红河常见杂草苣荬菜Sonchus arvensis上出现了疑似菜豆金色花叶病毒属病毒病症状。利用克隆、测序和生物信息学分析技术对其所含病毒进行分离鉴定,结果从1株病样中共获得了两条菜豆金色花叶病毒属病毒全序列、两条β卫星全序列和一条α卫星全序列。序列分析显示,两条菜豆金色花叶病毒属病毒全序列与中国胜红蓟黄脉病毒相似性最高,分别为99%和96%,确定为中国胜红蓟黄脉病毒的分离物。两条β卫星全序列与赛葵黄脉β卫星相似性最高,为97%,确定为赛葵黄脉β卫星的一个分离物。α卫星全序列与中国番茄黄化曲叶α卫星相似性最高,为86.3%,是中国番茄黄化曲叶α卫星的一个分离物。这是菜豆金色花叶病毒属病毒病害复合体在中国侵染苣荬菜的首次报道。     

从海南省杂草胜红蓟和假马鞭上检测到粉虱传双生病毒

 利用三抗体夹心ELISA(TAS-ELISA)及PCR检测的方法对采自海南的胜红蓟(Ageratum conyzoides)和假马鞭(Stachytarphetajamaicensis)的5个病样进行了检测,表明均为粉虱传双生病毒。PCR扩增产物克隆后进行序列测定,结果表明存在2类双生病毒,其中样品Hn2存在2类病毒的复合侵染。这是在海南首次报道存在有粉虱传双生病毒。     

3种牧草不同搭配方式对胜红蓟的替代控制

研究3种牧草不同搭配方式对胜红蓟的替代控制效果,为入侵杂草胜红蓟的防控提供植物种和替代控制方法.在田间条件下,通过将白三叶、杂交甜高粱、杂交狼尾草3种牧草两两等比例搭配后与胜红蓟按2∶1混种,建立3种不同的替代控制方式,动态监测各群落(种群)植物、土壤微生物指标,评价3种牧草两两等比例搭配对胜红蓟的替代控制效果.结果表明:白三叶、杂交甜高梁等比例搭配对胜红蓟进行替代控制时,2种牧草株高严重受阻,牧草相对盖度占优,Simpson指数和Shannon-wiener指数均变大,胜红蓟重要值变小,土壤真菌增多,细菌、放线菌减少;白三叶、杂交狼尾草等比例搭配对胜红蓟进行替代控制时,2种牧草株高不受阻,牧草相对盖度占优,Simpson指数变大,Shannon-wiener指数变小,胜红蓟重要值变小,土壤真菌增多,细菌、放线菌减少;杂交狼尾草和杂交甜高粱等比例搭配对胜红蓟进行替代控制时,杂交狼尾草株高不受阻,但杂交甜高梁株高严重受阻,牧草相对盖度占优,Simpson指数变小,Shannon-wiener指数变大,胜红蓟重要值变小,土壤细菌增多,真菌、放线菌减少.总体来看,白三叶和杂交狼尾草可以等比例搭配作为胜红蓟替代控制材料,且替代控制效果较好;白三叶和杂交甜高粱、杂交甜高粱和杂交狼尾草不宜等比例搭配作为胜红蓟的替代控制材料.     

胜红蓟次生物质对小菜蛾田间种群的控制作用

用生命表方法评价了胜红蓟次生物质对小菜蛾田间种群的控制作用,分析了其对小菜蛾田间种群自然控制因子的影响.结果表明,浓度为1000和1500μg·g-1的胜红蓟挥发油和胜红蓟素通过对小菜蛾田间种群的产卵忌避和降低成虫生殖能力等作用达到控制的效果.1000和1500μg·g-1的胜红蓟挥发油对小菜蛾田间种群的干扰作用控制指数(IIPC)分别为0.4826和0.5084,胜红蓟素的为0.4556和0.3205.但在胜红蓟次生物质的作用下,处理区天敌对小菜蛾的自然控制作用也受到了不同程度的削弱.     

双生病毒——一类值得重视的植物病毒

 双生病毒是世界范围内广泛发生的一类植物单链DNA病毒,已在多种作物上引起严重危害。重组是导致双生病毒变异和病害流行的重要原因。近年来,在单组份双生病毒中发现有新型卫星DNA分子——DNAβ,DNAβ是病毒致病所必需的。本文就双生病毒的危害性、病毒的重组、DNAβ的发现及与致病性的关系、双生病毒与伴随的小分子DNA形成病害复合体、双生病毒DNA-A和小分子DNA的进化关系等问题进行了简要评述。     

Compounds from Ageratum conyzoides: isolation, structural elucidation and insecticidal activity

This work aimed at identifying plant compounds with insecticidal activity against Diaphania hyalinata (L.) (Lepidoptera: Pyralidae), Musca domestica (L.) (Diptera: Muscidae), Periplaneta americana (L.) (Blattodea: Blattidae) and Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetaefolia L.), Jimson weed (Datura stramonium L.), 'baleeira' herb (Cordia verbenaceae L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.) and billy goat weed (Ageratum conyzoides L.). Firstly, the insecticidal activities of hexane and ethanol plant extracts were evaluated against adults of R. dominica. Among them, only the hexane extract of A. conyzoides showed insecticidal activity. The hexane extract of this plant species was therefore fractionated by silica gel column chromatography to isolate and purify its bioactive chemical constituents. Three compounds were identified using IR spectra, (1)H NMR, (13)C NMR, HMBC and NOE after gel chromatography: 5,6,7,8,3', 4', 5'-heptamethoxyflavone, 5,6,7,8,3'-pentamethoxy-4', 5'-methylenedioxyflavone and coumarin. The complete assignment of (13)C NMR to 5,6,7,8,3'-pentamethoxy-4', 5'-methylenedioxyflavone was successfully made for the first time. 5,6,7,8,3'-Pentamethoxy-4', 5'-methylenedioxyflavone did not show any insecticidal activity against the four insect species tested. 5,6,7,8,3', 4', 5'-Heptamethoxyflavone showed low activity against D. hyalinata and R. dominica and was not toxic to M. domestica or P. americana. In contrast, coumarin showed insecticidal activity against all four insect pest species tested, with the following order of susceptibility: R. dominica < P. americana < D. hyalinata < M. domestica after 24 h exposure.     

利用蚕豆根尖微核试验研究入侵植物胜红蓟的化感作用潜力

[目的]研究入侵植物胜红蓟(Ageratum conyzoides Linn.)的化感作用潜力。[方法]运用蚕豆(Vicia fabaL.)根尖细胞微核试验研究入侵植物胜红蓟叶、茎、花以及地上部分(除去根以外的植物体,下同)水浸提液的化感效应。[结果]胜红蓟水浸提液具有较强的遗传毒性。在叶、茎、花和地上部分水浸提液作用下,蚕豆根尖细胞有丝分裂指数下降,微核率升高,细胞中出现了微核、染色体桥、染色体环等多种染色体畸变,胜红蓟水浸提液对蚕豆根尖的影响存在显著的浓度效应。胜红蓟叶、茎、花和地上部分的整体效应为叶>茎>花>地上部分,与地上部分相比三部位之间的化感作用潜力不存在简单加和作用,但仍以叶片效应最强。[结论]叶片具有最高的化感作用潜力。     

Ecological pest management and control by using allelopathic weeds (Ageratum conyzoides,Ambrosia trifida,and Lantana camara) and their allelochemicals in China

The development of pest management and control is striving toward a future of sustainable agriculture. Weeds cause serious problems in agricultural ecosystems and attempts to control them have met with limited success. However, many weeds are allelopathic; that is, they can produce and release allelochemicals to interact with other plant competitors and to attack microbes or insect and other animal predators. These allelopathic weeds and their allelochemicals may be put into use for ecological pest management and control or employed for other uses. Currently, little attention has been paid to how allelopathic weeds and their allelochemicals potentially can be utilized as an important part of pest management and control in agricultural ecosystems. This review outlines recent research regarding the potential for pest management and control by allelopathic weeds and their allelochemicals by studying the cases of Ageratum conyzoides, Ambrosia trifida, and Lantana camara and provides examples of allelopathic weeds and their allelochemicals that have been incorporated into ecological pest management and control in China.     

垂序商陆及胜红蓟提取物对降香黄檀炭疽病菌的抑菌机理研究

通过测定垂序商陆与胜红蓟乙酸乙酯提取物处理后的降香黄檀炭疽病菌内丙二醛含量、蛋白质含量以及4种酶活性,来初步判断垂序商陆与胜红蓟提取物对炭疽病菌的作用机理。结果表明:两种提取物都能在一定程度上破坏炭疽病病原菌膜系统,垂序商陆处理组丙二醛含量在56h后显著提高,胜红蓟处理组则缓慢增加,略高于对照组;垂序商陆处理组菌体内蛋白质含量先增加,32h后急剧降低,胜红蓟处理组蛋白质含量从初期开始就少于对照组;两种提取物都能影响菌体的保护性酶活性,两处理组SOD活力都呈现先增高后降低的趋势,CAT活力高于对照组。两组SDH、LDH活力都小于对照组,而垂序商陆处理组SDH、LDH活力小于胜红蓟处理组。初步说明两种植物提取物可通过影响病原菌的代谢系统和生理过程来发挥其抑菌作用。     

Species diversity,phylogeny and genetic variability of begomovirus populations infecting leguminous weeds in northeastern Brazil

A survey of begomoviruses infecting leguminous weeds (family Fabaceae) was carried out in four states of northeastern Brazil. A total of 26 full‐length begomovirus components (19 DNA‐A and seven DNA‐B, with three pairs of cognate A and B components) were amplified using rolling‐circle amplification, then cloned and sequenced. Sequence analysis indicated the presence of six species, four of them novel. In phylogenetic analysis five of the viruses clustered with other Brazilian begomoviruses, but one of them (Euphorbia yellow mosaic virus, EuYMV) clustered with viruses from other countries in Central and South America. Evidence of recombination was found among isolates of Macroptilium yellow spot virus (MaYSV). The MaYSV population had a high degree of genetic variability. Macroptilium lathyroides was revealed as a common host for several of these viruses, and could act as a mixing vessel from which recombinant viruses could emerge. The results indicate that leguminous weeds are reservoirs of several begomoviruses in Brazil, and could play a significant role in begomovirus epidemics, both as inoculum sources and as sources of emerging novel viruses.