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.

Molecular Characterization of Segments S7 to S10 of a Southern Rice Black-streaked Dwarf Virus Isolate from Maize in Northern China

Southern rice black-streaked dwarf virus (SRBSDV) is a novel Fijivirus prevalent in rice in southern and central China,and northern Vietnam. Its genome has 10 segments of double-stranded RNA named S1 to S10 according to their size. An isolate of SRBSDV,JNi4,was obtained from naturally infected maize plants from Ji'ning,Shandong province,in the 2008 maize season. Segments S7 to S10 of JNi4 share nucleotide identities of 72.6%-73.1%,72.3%-73%,73.9%-74.5% and 77.3%-79%,respectively,with corresponding segments of Rice black-streaked dwarf virus isolates,and identities of 99.7%,99.1%-99.7%,98.9%-99.5%,and 98.6%-99.2% with those of SRBSDV isolates HN and GD. JNi4 forms a separate branch with GD and HN in the phylogenetic trees constructed with genomic sequences of S7 to S10. These results confirm the proposed taxonomic status of SRBSDV as a distinct species of the genus Fijivirus and indicate that JNi4 is an isolate of SRBSDV. Shandong is so far the northernmost region where SRBSDV is found in China.

The Control Effect of Prevention and Control Technology Combination against Southern Rice Black-Streaked Dwarf Disease

Objective] This study aimed to explore a better prevention and control technology combination against southern rice black-streaked dwarf disease. [Method] The control effects of seed dressing, antiviral agents and fly net along with 25%pymetrozine against southern rice black streaked dwarf disease were determined. [Result] When the seeds were dressed with 60% imidacloprid （FS, 2 g a.i./kg）, and the rice seedlings were sprayed once with 25% pymetrozine （WP, 360 g/hm2） 10 d before the transplanting and sprayed twice with 30% Dufulin （WP, 800×） at three-leaf stage and 7 d after the transplanting respectively, the control efficiency reached 88.05%. When fly net and pesticides were applied simultaneously, the fly net was lifted and 25% pymetrozine （WP） was spayed once on the rice seedlings at six-leaf stage and the seedlings were hardened for 3 d and sprayed once with 25%pymetrozine （WP） 10 d after the transplanting, the control efficiency reached 80.50%. [Conclusion] Seed dressing or applying antiviral agents alone can not better control diseases. The southern rice black-streaked dwarf disease can be better con-trol ed by seed dressing, along with spraying of planthopper-kil ing agents at two-leaf stage, 3 d before the transplanting and 7 d after the transplanting, respectively. If condition al ow, fly net can be instal ed to achieve better control effect.

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.

Occurrence and Chemical Control Techniques of Rice Black-streaked Dwarf Disease in Rongshui County

The chemical control technologies of southern rice black-streaked dwarf disease in hybrid rice were studied in Rongshui County,Guangxi,through a combination of investigation,observation and experiments.Three treatments were set up,namely,no water,shallow water and deep water,and each of which had a treatment area of 67 m^(2).Each treatment was sprayed once with 40 g of 200 million/g Bacillus subtilis wettable powder and 20-30 g of 25%pymetrozine wettable powder per 667 m^(2) in a mixture with 30 kg of water.On the day of spraying,100 diseased rice hills in each treatment were marked for field observation.The test results showed that the control of southern rice black-streaked dwarf disease should be done by draining the field water and spraying the mixture of B.subtilis and pymetrozine evenly,and a better effect can be achieved by keeping the field moist for 6-7 d after spraying.

Analysis of black-streak defects on food-container screw caps

The cause of black-streak defects on food-container screw caps is analyzed by two-dimensional gas chromatography time-of-flight mass spectrometry,morphological analysis,and energy-dispersive X-ray spectroscopy.An immersion experiment was conducted with the cap immersed in different concentrations of acetic acid to simulate the growth of black streaks.The experimental results show that the acetic acid concentration in food is closely related to the appearance of the black-streak defects.Acetic acid is speculated to permeate into the gaps of the cap,followed by the formation of ferric acetate(light brown solid).The ferric acetate then breaks through the paint surface and its color coincides with that of the paint,which leads to the formation of the black-streak defects.

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.

气象因子对河池市南方水稻黑条矮缩病发展的影响

利用河池市2005—2023年南方水稻黑条矮缩病(SRBSDV)的发病面积比例数据和期间气象数据,通过卡方分布的概率密度函数拟合流行周期内的发病趋势概率,分离出发病浮动概率,探究关键气象因子与发病浮动概率的相关性,并基于显著相关气象因子构建发病气象评价模型。结果表明:(1)2010年为河池市SRBSDV的暴发期,2010—2023年为SRBSDV的一个流行周期,发病概率符合自由度为3的卡方分布的概率密度函数;(2)发病浮动概率与12月—次年2月的平均气温、6—7月的降水量和相对湿度呈显著正相关,与安全播种期日序数负相关;(3)发病气象评价模型在预测暴发期的发病程度时预测偏轻,其他年份均预测正确,模型在一个流行周期内的定性评价效果较好。通过气象发病评价模型可定性评价流行周期内的发病程度,研究结论可为河池市的水稻病害防治工作提供参考依据。

南方水稻黑条矮缩病毒在广西兴安的迁入与侵染动态

广西兴安地处白背飞虱Sogatella furcifera(Horváth)迁入廊道要冲,南方水稻黑条矮缩病毒(southern rice black-streaked dwarf virus,SRBSDV)依赖白背飞虱携传。本研究采用探照灯诱集高空白背飞虱,同时采集田间白背飞虱和稻叶,采用dot-ELISA法检测白背飞虱及水稻的带毒状况,以明确SRBSDV的迁入与侵染动态。综合来看,2021年-2022年间兴安的带毒白背飞虱迁入始期为5月下旬,迁入白背飞虱的带毒率高峰为6月中下旬;田间白背飞虱7月上旬-7月下旬带毒率较高(10%~15%);水稻7月中旬-8月上旬带毒率较高(10%~14%)。水稻带毒率与田间白背飞虱带毒率之间存在显著相关关系。本文结果有助于桂北和长江中下游地区开展白背飞虱携传SRBSDV的监测预警。

Southern rice black-streaked dwarf virus:A new proposed Fijivirus species in the family Reoviridae

For the past several years, a novel dwarf disease has been observed on rice (Oryza sativa) in some regions of Guangdong Province and Hainan Province, southern China. Infected plants showed stunting, dark leaf and small enations on stem and leaf back. Typical Fijivirus viroplasma containing crystalline arrayed spherical virons approximately 70―75 nm in diameter and tubular structures were detected in ultrathin sections by an electron microscope in parenchyma phloem cells of the infected plants. The virus was transmitted to rice seedlings by white-backed planthoppers, Sogatella furcifera (Hemiptera: Delphacidae), collected in the diseased fields. Analysis of dsRNA extracts from infected plants revealed ten linear segments, which were similar to the electrophoretic profile of Rice black-streaked dwarf virus (RBSDV). RT-PCR with a single primer which matched to a linker sequence ligated to both 3′ ends of the viral genomic dsRNAs resulted in amplification of genome segments 9 (S9) and 10 (S10) cDNA products. The complete nucleotide sequences of S9 and S10 were obtained from clones of the RT-PCR amplicon exhibited characteristic properties of Fijivirus including low GC content (34.5% and 35.6%), genus conserved 5′ and 3′ termini sequences and similar genome organization. Blast searches indicated that the sequences of S9 and S10 shared 68.8%―74.9% and 67.1%―77.4% nucleotide identities with those of viruses in the Fijivirus group 2, respectively. These values were similar to those among other viruses in the Fijivirus group 2 and considerably lower than those among RBSDV isolates. Phylogenetic trees based on S9 and S10 nucleotide sequences and their putative amino acid sequences showed that this virus represented a separate branch among other Fijiviruses. The virus was also detected by a nested RT-PCR assay in corn (Zea mays), barnyard grass (Echinochloa crusgalli), Juncellus serotinus and flaccidgrass (Pennisetum flaccidum) in and/or adjacent to the infected rice fields. It is proposed that this virus be considered as a new species, Southern rice black-streaked dwarf virus, in the group 2 of the genus Fijivirus in the family Reoviridae.

南方水稻黑条矮缩病抗病遗传资源与分子机理研究进展

南方水稻黑条矮缩病(Souther rice black-streaked dwarf virus disease,SRBSDVD)是依靠白背飞虱(Sogatella furcifera)为传播介体,由南方水稻黑条矮缩病毒(Southern rice black-streaked dwarf virus,SRBSDV)侵染引起的一种水稻病毒病。该病害于2001年在我国华南地区首次被发现,随后发生面积不断扩大,危害逐年加重,已成为近年来危害中国南方稻区水稻生产的重要病害之一。白背飞虱迁飞性强、种群数量大、传毒持久等特点,导致化学农药防虫治病效果并不理想,至今还未有可持续和绿色控制SRBSDVD的手段。根据病原病毒的爆发性及其传播介体白背飞虱的生物学特性,预计该病害在未来较长的一段时期内将是我国最严重的水稻病害之一,很有可能再次暴发流行。因此,当前生产上急需培育出能够抵御SRBSDVD的抗性水稻品种。本文综述了SRBSDVD的发病规律、抗病种质资源的收集与评估、抗病基因或数量性状位点(QTL)的精确定位,以及这些抗性基因的分子作用机制,进一步探讨了利用现代分子生物学技术,包括分子标记辅助选择、基因沉默(RNAi)和基因编辑等技术加快SRBSDVD抗病品种的选育,可为今后有效控制SRBSDVD提供基础。

Detection,Occurrence,and Survey of Rice Stripe and BlackStreaked Dwarf Diseases in Zhejiang Province,China

The major viral diseases that occur on rice plants in Zhejiang Province, eastern China, are stripe and rice black-streaked dwarf diseases. Rice stripe disease is only caused by rice stripe tenuivirus （RSV）, while rice black-streaked dwarf disease can be caused by rice black-streaked dwarf fijivirus （RBSDV） and/or southem rice black-streaked dwarf fijivirus （SRBSDV）. Here we review the characterization of these viruses, methods for their detection, and extensive surveys showing their occurrence and spread in the province.

一种快速同步检测水稻黑条矮缩病毒和南方水稻黑条矮缩病毒的方法

水稻黑条矮缩病毒和南方水稻黑条矮缩病毒是近年来在水稻上危害日益严重的两种病毒,由于两者同属于呼肠孤病毒科斐济病毒属,在症状、粒体形状、传播介体及寄主等方面非常相似,由此也给诊断及鉴定造成了困难。针对这一问题,通过设计简并引物,并优化体系,建立了一种快速、简便、灵敏、特异的方法,为这两种病毒的检测及鉴别提供了方便。

水稻新病害南方水稻黑条矮缩病发生特点及危害趋势分析

由斐济病毒属(Fijivirus)暂定新种南方水稻黑条矮缩病毒(Southern rice black-streaked dwarf virus,SRBSDV)引起的水稻矮缩病,自2001年在广东省阳西县被发现以来,已迅速扩散至我国南方广大稻区。2009年,该病害在我国南部及越南晚季稻上暴发成灾,造成严重的产量损失。本文简介了该病害的症状、危害特点、病原病毒及其传毒介体特征,对其发生趋势进行了讨论,提出了以秧苗期治虫为重点的病害防控应急措施。

水稻黑条矮缩病抗性资源的筛选和抗性QTL的定位

通过水稻黑条矮缩病的田间鉴定发现,分蘖盛期的病状最为显著,是病症观察的最佳时期。对江苏省311份粳稻品种进行重病区田间鉴定试验,未发现对黑条矮缩病毒(RBSDV)免疫的品种。江苏省目前正在推广的24个主栽水稻品种发病率在10.0%～30.0%之间,曾推广的287份粳稻品种中,71.5%的品种发病率在10.0%～29.0%之间,其余品种发病率在29%以上。来源于日本的粳稻品种Koshihikari的黑条矮缩病发病率相对较低,籼稻高产品种桂朝2号为感病品种。利用Koshihikari/桂朝2号RILs群体进行抗RBSDV的基因定位,结果在第3染色体上标记RM7～RM5748之间检测到1个抗黑条矮缩病的QTL,来自Koshihikari的等位基因增强了水稻黑条矮缩病的抗性,携带抗性位点的家系明显提高了对RBSDV的抗性。本研究结果将为研究水稻黑条矮缩病和水稻抗黑条矮缩病分子育种提供重要信息。

湖北发生的水稻矮缩病是南方水稻黑条矮缩病毒引起的

近年来由水稻黑条矮缩病毒和南方水稻黑条矮缩病毒引起的水稻黑条矮缩病在华南、华东等地区暴发流行,给水稻生产带来严重损失,而湖北一直未有水稻黑条矮缩病流行的报道。然而,2009年和2010年在湖北省长江沿线的荆州、孝感、咸宁、黄石、鄂州、黄冈等水稻种植区普遍发生水稻矮缩减产的现象。经过症状观察、dsRNA电泳图谱分析、RT-PCR等方法,诊断该病是由南方水稻黑条矮缩病毒引起,说明该病毒已经随介体昆虫白背飞虱从我国南方传播至中部水稻种植区。

灰飞虱从冷冻病叶获得水稻黑条矮缩病毒方法的研究初报

研究出一种利用灰飞虱从冷冻病叶中获得水稻黑条矮缩病毒(riceblack-streaked dwarf virus,RBSDV)的方法。以-70℃条件下冷冻保存的RBSDV罹病植株叶片对灰飞虱饲毒,随后接种感病水稻品种,结果发现灰飞虱可从冷冻病叶上获得RBSDV,并传播RBSDV,且获毒能力和传毒能力与新鲜病叶没有差异。这表明从冷冻病叶上获得RBSDV的灰飞虱可以应用于品种抗性鉴定,此法可望加快RBSDV抗病品种的选育进程。

应用RT-PCR、斑点杂交法和SDS-PAGE检测水稻黑条矮缩病毒

用RT PCR技术、PCR标记的探针点杂交和SDS PAGE检测了生产上严重危害玉米和水稻的水稻黑条矮缩病毒(RBSDV)。由RT PCR扩增的RBSDV第 7片段第 92 1～ 14 11碱基作探针 ,用PCR法DIG标记后点杂交 ,可以从 10 0ng玉米病叶中检测到RBSDV ,灵敏度是RT PCR的 1/10 ;10 %SDS PAGE只能检测到从 1g玉米病叶中提取的病毒dsRNA ,但对江苏玉米田间分离的不同的RBSDV样品电泳发现 ,该病毒基因组dsRNA有差异 。

南方水稻黑条矮缩病毒S6编码一个沉默抑制子

【目的】分析南方水稻黑条矮缩病毒(SRBSDV)基因组S6编码的SP6蛋白的抑制子活性,明确SRBSDV是否编码RNA沉默抑制子来干扰植物的沉默。【方法】将分别含有SP6与GFP质粒的农杆菌共浸润转GFP基因的16c本氏烟纯合系,观察SP6对局部沉默和系统沉默的抑制作用;将含有SP6,GFP和dsGFP质粒的农杆菌三者共浸润,观察SP6对由dsRNA引起的沉默的抑制作用;在同一植株不同部位接种GFP和SP6,观察SP6对RNA沉默信号传导的影响;通过马铃薯X病毒(Potato virus X,PVX)在本氏烟上表达SP6,观察SP6是否能增强PVX的致病性。【结果】SP6能抑制由GFP正义RNA介导的沉默,但其抑制作用较弱,仅能延缓局部沉默和系统沉默的产生。SP6能灭活RNA沉默信号,阻止沉默信号的长距离传导,回复GFP的沉默,但不能抑制由dsRNA引起的沉默。利用PVX在本氏烟上表达SP6能增强PVX的致病性。【结论】SP6是病毒编码的RNA沉默抑制子,在RNA沉默的起始和信号传导阶段起作用。