The Efficiency of Southern rice black-streaked dwarf virus Transmission by the Vector Sogatella furcifera to Different Host Plant Species

Southern rice black-streaked dwarf disease is a new rice disease that severely affects rice production in South China.To understand transmission capacity of the vector Sogatella furcifera to Southern rice black-streaked dwarf virus（SRBSDV） among different host plant species,potential host plants of SRBSDV collected from the diseased rice field and/or adjacent to the field in Hunan Province,China,were determined by RT-PCR,and the transmission rates of SRBSDV by S.furcifera among different host plant species were investigated.The results showed that host plants of SRBSDV in the rice fields were five of family Gramineae（Oryza sativa,Echinochloa crusgalli,Zea mays,Paspalum distichum,Alopecurus aequali） and two of family Cyperaceae（Juncellus serotinus and Cyperus difformis）.S.furcifera could not transmit SRBSDV between gramineous plants and cyperaceous plants,and could not transmit SRBSDV between the gramineous plants,J.serotinus and C.difformis as well.However,SRBSDV could be transmitted by S.furcifera within gramineous plants.S.furcifera could transmit SRBSDV between interspecies among three species plants（O.sativa,E.crusgalli and Z.mays）,and between P.distichum and A.aequali.At 15,20,25,30,and 35°C,both macropterous and brachypterous adult of S.furcifera could transmit SRBSDV from the plants（e.g.,E.crusgalli,Z.mays and O.sativa） infected with SRBSDV to rice seedlings.The transmission rates were first increased and then decreased with the increase of temperature.Macropterous adults transmitted SRBSDV from the viruliferous E.crusgalli,Z.may and rice plants to the healthy rice seedlings,and the infected rates of rice seedlings were 26.2,18.8 and 23.7% at 15°C,56.6,64.6 and 53.6% at 25°C,and was 11.2,10.2 and 7.3% at 35°C,respectively.Transmission capacity of brachypterous adults was significantly higher than that of macropterous adults at 15,20 and 25°C（P0.05）,while transmission capacity of brachypterous adults was relatively lower compared with that of macropterous ones at 35°C.These results offer evidence on the transmission of SRBSDV via the vector S.furcifer among different host plants,which can be helpful to control Southern rice black-streaked dwarf disease by the appropriate cultural measures in South China.

Transmission of Rice Black-Streaked Dwarf Virus from Frozen Infected Leaves to Healthy Rice Plants by Small Brown Planthopper (Laodelphax striatellus)

In order to preserve virus for identifying the resistance of rice varieties against rice black-streaked dwarf disease, a simple and reliable method was developed, through which virus-free small brown planthopper （SBPH） acquired rice black-streaked dwarf virus （RBSDV） from frozen infected leaves and the virus was transmitted to healthy rice plants. The experimental results showed that SBPH could obtain RBSDV from frozen infected rice leaves and the virus could be transmitted to a susceptible rice variety. For the ability to acquire RBSDV and transmit the virus to healthy plants by SBPH, there was no significant difference between frozen infected leaves and in vitro infected leaves. The novel method could be applied to identification of rice variety resistance to rice black-streaked dwarf disease, facilitating the breeding process for rice black-streaked dwarf disease resistance.

Resistance of Major Rice Cultivars in Hangzhou Area of China against Southern Rice Black-streaked Dwarf Virus

Resistance of 17 major rice cultivars in Hangzhou region of China against southern rice black-streaked dwarf virus was tested in the paper. The results showed that the incidence rate of southern rice black-streWed dwarf virus had certain positive correlation with quantity of white-backed planthopper （Sogatellafurci-fera） and resistance among various cultivars was significant. Two varieties, Yueyou 9113 and Tianyouhuazhan, were most susceptible ; Yongyou 8, Jiayou 2 and Xi-ushui 134 had best resistance and could be used as disease-resistant varieties to prevent the disease.

Prevalence Characteristics of Rice Black-streaked Dwarf Virus Disease and Continuous Control Strategies

Through summarizing the prevalence characteristics of rice black-streaked dwarf virus disease(RBSDVD)in Linyi City of Shandong Province,this paper analyzed its prevalence is related to changes in farming and cultivation systems,the increase in the population of venomous Laodelphax striatellus Fallén and its own migration and spread,the poor disease resistance of cultivated varieties,and inadequate time of prevention and control.Besides,based on the practice of local control,it came up with some comprehensive control measures including strengthening monitoring,early warning and forecasting,planting resistant(tolerant)rice varieties according to local conditions,appropriately delaying the sowing(planting)period,supplemented by insect nets to cover seedlings,and making scientific use of chemical control.It is expected to provide a reference for the prevention and control of RBSDVD.

Screening of Rice Genes Interacting with p5b of Rice BlackStreaked Dwarf Virus

Rice black-streaked dwarf virus （RBSDV） is a recognized member of the genus Fijivirus, family Reoviridae. Its genome has ten double-stranded RNA （dsRNA） segments （$1-$10）, in which the fifth genome segment （$5） contains two open reading frames （ORFs） with a partially overlapping region. The second ORF of RBSDV S5 encodes a viral nonstructural protein named p5b with unknown function. To reveal the function of p5b, its gene was ligated into the bait plasmid pGBKT7 and an expression library containing rice cDNAs was constructed using plasmid pGADT7 for yeast two-hybrid assay. The bait protein p5b was detected in yeast by western blot, and the result of an auto-activation test showed that p5b could not autonomously activate the expression of reporter genes in yeast. Then the bait protein p5b was used for screening the cDNA expression libraries of rice. Gene fragments of some pivotal enzymes involved in photosynthesis, respiration and other important metabolic processes, were identified to interact with p5b in yeast, suggesting that these interactions may play roles in symptom development in infected plants.

Disaster Prevention and Mitigation Technologies of Rice Virus Diseases Spread by Small Brown Planthopper (SBPH)

Rice stripe virus disease （RSVD） and rice black-streaked dwarf virus disease （RBSDVD） are two epidemic diseases in Yancheng City, Jiangsu Province in the last decade. The authors investigated the disaster regularity, prevention and control technology of RSVD and RBSDVD systematically. The occurrence and virus transmission of SBPH and disaster regularity of virus diseases were studied; the resistance of some rice varieties was cleared; the effects of physical and agricultural measures such as insect net blocking, appropriate late sowing and plowing on controlling occurrence and virus transmission of SBPH were figured out; a hatch of chemical agents were screened, providing efficient and harmless pesticides for effective control against SBPH and prevention against virus diseases. A set of disaster control and mitigation technologies was proposed in this paper, which was practical, sustainable, and easy to operate for the local planting patterns.

Epidemiological Characteristics of Maize Rough Dwarf Disease in Huang-Huai-Hai Plain

Maize rough dwarf disease is a common epidemic disease in large areas.Its epidemic and occurrence mechanism is a complex process.In this paper,the epidemiological characteristics and influencing factors of maize rough dwarf disease in Huang-Huai-Hai plain were elaborated based on the research results of maize rough dwarf disease at home and abroad for many years.The epidemic of maize rough dwarf disease is affected by many factors,such as the occurrence and virus carrying rate of the first generation small brown planthopper,accumulation of virus sources on gramineous crops and weed hosts,maize variety resistance,maize sowing date,maize growth period,crop layout,tillage system,climate and ecological environment.The key factors causing the outbreak and epidemic of maize rough dwarf disease are the planting of maize susceptible varieties,the meeting of maize seedling stage and the peak period of adult spread of the first generation of small brown planthopper.

江苏省近年来新发生的一种水稻矮缩病害病原初步鉴定

通过常规生物学和分子生物学手段,对近年来在江苏省发生的一种危害严重的水稻矮缩病进行了初步诊断和鉴定,结果显示该病为水稻黑条矮缩病毒所致。这是自1963年以来水稻黑条矮缩病在江苏省大面积发生危害的首次报道。

水稻黑条矮缩病毒第七号片段的cDNA克隆及其在大肠杆菌中的表达

运用RT PCR技术 ,根据玉米粗缩病毒S6的末端序列设计引物 ,从玉米粗缩病感病材料中克隆得到一条 2 2kb长的cDNA片段 ,序列分析表明 ,该片段全长 2 1 93bp ,含两个开放阅读框 ,分别编码 41 0kD和 36 3kD的多肽。序列分析结果表明 ,该cDNA片段及其编码产物与水稻黑条矮缩病毒S7的cDNA序列及编码产物存在最高的相似性 ,推测该cDNA片段为水稻黑条矮缩病毒的S7片段 ,而不是玉米粗缩病毒的S6。分别将该片段的两个阅读框克隆到原核表达载体pET2 1 d及pGEX KG中 ,经IPTG诱导后 ,两种蛋白均得到了高效的表达。表达产物回收后制备并得到了高效价的抗血清。

双重RT-PCR法同时快速检测南方水稻黑条矮缩病毒和水稻黑条矮缩病毒

南方水稻黑条矮缩病毒(SRBSDV)和水稻黑条矮缩病毒(RBSDV)在病害症状、传播介体及寄主等方面非常相似,田间很难对其进行诊断及鉴定。根据SRBSDV与RBSDV外壳蛋白(CP)基因核苷酸序列差异设计特异性引物,建立一种快速、准确的双重PT-PCR鉴别方法,为SRBSDV和RBSDV的流行监测提供技术支持。

抗水稻黑条矮缩病毒和南方水稻黑条矮缩病毒的双价RNA沉默载体的构建

为利用RNAi技术获取抗水稻黑条矮缩病毒(RBSDV)和南方水稻黑条矮缩病毒(SRBSDV)植株,分别针对两种病毒的S6和S10基因构建RNA沉默载体。采用重组PCR方法将RBSDV S6基因片段(R6)和SRBSDVS6基因片段(SR6)进行融合,获得600 bp的R6-SR6融合基因;将RBSDV S10基因片段(R10)和SRBSDV S10基因片段(SR10)进行融合,获得600 bp的R10-SR10融合基因。融合基因以反向重复的方式连入pBS载体,并定向插入到pCAMBIA1301载体上,获取了含有发夹结构的植物表达载体pCAMBIA1301-hp(R6-SR6)和pCAMBIA1301-hp(R10-SR10)。抗RBSDV和SRBSDV RNA沉默载体的构建为利用RNA沉默进行植物抗病毒研究奠定了基础。

玉米粗缩病灰飞虱传毒模型的建立

本文用麦夸特法(Marquardt)拟合了多种假定模型的参数,获得了玉米粗缩病灰飞虱接虫传毒模型:其中P、T、N分别表示接虫传毒后玉米成株期的发病率,接毒时间(h)和接虫数量(头/株)。F回归**=17.0235,R=0.8726。模型表明在玉米上灰飞虱传播RBSDV的有效性较高,短时间内以有效虫量接毒即可获得较高的发病率,随着时间的延长或接虫量的增加,病株率增长的幅度越来越小;模型揭示,对玉米粗缩病采用治虫控病措施时,在短时间内迅速杀灭毒灰飞虱个体,才能达到较好的防治效果。并对建模过程进行了验证。P=C11+C2exp(-(C3T+C4N))=85.7231+10.391exp(-(1.3582T+0.1889N))

侵染安徽玉米的水稻黑条矮缩病毒全基因组特征

[目的]测定水稻黑条矮缩病毒（Rice black-streaked dwarf virus,RBSDV）安徽分离物全基因组序列,分析RBSDV安徽分离物与RBSDV其他分离物以及斐济病毒属（Fijivirus）其他成员之间的分子差异,为明确RBSDV遗传变异与进化规律提供重要信息.[方法]采用RT-PCR法从安徽玉米粗缩病样本中扩增RBSDV的全基因组,克隆、测序并进行序列分析.[结果]获得RBSDV安徽分离物全基因组序列.序列比对发现,RBSDV安徽分离物与其他RBSDV各个分离物S1到S10的序列相似性较高,为87.6%-99.5%,其中与RBSDV韩国分离物（RBSDV-KOR）序列相似性最高,达94.6%-99.5%;从构建的系统关系树也可以看出,RBSDV安徽分离物和其他所有RBSDV分离物均聚成一个单独的分支.[结论]RBSDV各分离物之间亲缘关系很近.RBSDV安徽分离物与RBSDV-KOR亲缘关系最近,可能起源于相同的祖先.另外,推测RBSDV各个基因组片段可能是协同进化的.

玉米粗缩病抗性相关miRNA的筛选

水稻黑条矮缩病毒(Rice black streaked dwarf virus,RBSDV)引起的玉米粗缩病是我国玉米生产中的一类重要病害,严重威胁我国玉米生产。MicroRNA(miRNA)是一类内源的小分子非编码RNA,作为真核生物基因表达中的一类调控因子,在抵御病毒入侵方面起着非常重要的作用。本研究通过对不同抗性玉米品种人工接种RBSDV,构建茎秆及叶片miRNA文库共8个。利用高通量测序,共获得150个已知miRNA前体序列和474个新miRNA序列。miRNA差异表达分析表明,两品种间叶片组织中表达趋势相反的miRNA有17个,茎秆组织中表达趋势相反的miRNA有10个。对差异表达的miRNA进行靶基因预测,共得到1 870个靶标基因,通过KEGG和GO富集分析,得出差异表达miRNA的表达模式。本试验为玉米抗粗缩病分子机理研究奠定了基础。

水稻黑条矮缩病毒的研究进展

水稻黑条矮缩病毒(Rice black streaked dwarf virus,RBSDV)属于呼肠孤病毒科斐济病毒属第二组成员,其引起的水稻黑条矮缩病在中国稻区造成巨大的经济损失。文章简述了水稻黑条矮缩病的危害情况及病毒特性、病毒各个编码蛋白的研究现状、应用基因工程控制病害等方面的研究进展,为今后对水稻黑条矮缩病的研究提供参考。

抗水稻黑条矮缩病转基因材料的鉴定分析

针对水稻黑条矮缩病毒(RBSDV)的核心粒子外壳蛋白基因(S8)、毒质与非结构蛋白基因(S9)及其嵌合基因(S8&S9)构建了6个RNAi载体,经农杆菌介导转化武陵粳1号获得转基因植株。通过潮霉素溶液浸泡法对转基因植株进行初步筛选,剔除假阳性植株;再通过PCR从DNA水平进行转基因阳性鉴定;进一步通过q RT–PCR从RNA水平进行转基因表达量分析。选取q RT–PCR表达量高的单拷贝纯系S8后代进行灰飞虱传毒试验,结果表明,含有S8 RNAi片段的转基因水稻材料对RBSDV具有一定抗性。

与水稻黑条矮缩病毒p5b互作的水稻基因片段筛选

由水稻黑条矮缩病毒基因组S5片段第2个开放阅读框(ORF)编码的p5b是一个功能未知的病毒非结构蛋白。构建了酵母双杂交体系的含水稻cDNA表达文库的pGADT7载体,同时将p5b基因构建到诱饵质粒pGBKT7上(pGBK-p5b),Western Blot和自激活实验结果显示p5b可在酵母中正确表达且无自激活活性。进一步利用p5b蛋白作为诱饵用酵母双杂交筛选水稻cDNA表达文库,鉴定出一些参与光合作用、呼吸作用等重要代谢过程的关键酶基因片段,这些酶可能与p5b蛋白之间存在相互作用,推测这些互作在病株症状发展过程中起作用。

水稻黑条矮缩病田间发病规律及防控技术初探

通过系统的田间调查,发现水稻黑条矮缩病与秧田灰飞虱特别是灰飞虱成虫的发生消涨关系一致,与大田灰飞虱发生无相关性。在建湖黑条矮缩病只有1个显症峰,距秧田灰飞虱成虫高峰约40～45 d。由于抗病品种发病轻,病穴率低,病株可恢复,成穗多,最终产量损失小,故在水稻黑条矮缩病发病区可选种抗病品种。此外,还可采取改变耕作方式、秧田覆盖防虫网、科学开展化学防治控灭灰飞虱、选择合适的栽培方式避开灰飞虱传毒、促病株恢复等多种防控技术措施。

玉米抗病毒基因工程研究进展

病毒病是导致玉米产量降低和品质下降的主要原因之一。在我国,玉米矮花叶病和粗缩病发生范围最广、危害最严重。基因工程技术可人为将抗性基因或部分片段定向导入植物获得转基因抗病毒植株,具有速度快、效率高等优点,在玉米抗病毒育种中具有重要的应用价值。文章在总结我国主要玉米病毒病及其病原种类的基础上,论述采用不同策略培育抗病毒玉米植株的研究进展,其中,利用植物病毒基因序列的策略有病毒编码蛋白基因介导的抗病性、RNA干扰(RNAi)介导的抗病性、人工小RNA(amiRNA)介导的抗病性3种,还可利用非植物病毒基因,包括寄主的抗性基因及来自其他植物、动物和微生物的抗病毒基因如核糖体失活蛋白、核酸酶、2-5A体系的基因等;最后分析各种策略的优缺点及抗病毒转基因玉米的安全性问题,为科研工作者优化玉米抗病毒育种工程、培育生产上可推广的抗病毒品种提供参考。

水稻黑条矮缩病抗性遗传研究进展

水稻黑条矮缩病(RBSDVD,rice black-streaked dwarf virus disease)是以灰飞虱为主要传毒介体,由水稻黑条矮缩病毒(RBSDV,rice black-streaked dwarf virus)引起的一种水稻病毒性病害。介体灰飞虱一经染毒,终身带毒,但不能通过虫卵传毒。近十几年水稻黑条矮缩病在中国南方稻区广为流行,造成了水稻的严重减产。目前主要通过使用农药来防治其传毒介体灰飞虱,但由于灰飞虱种群数量大,导致其防治效果不佳,而且存在环境污染的忧患,故培育和利用抗水稻黑条矮缩病的水稻品种是综合防治水稻黑条矮缩病的基础。本文对水稻黑条矮缩病的分布及危害、抗病种质资源、抗性鉴定方法、抗病基因/QTL的定位、抗病分子机理及育种进行综述,为开展水稻黑条矮缩病抗性遗传研究和品种选育提供参考。