Plant virus disease problems in the developing world. Evaluation of rice tungro disease management strategies outputs 1, 4 and 5. Prospects of virusresistant varieties for controlling rice tungro disease in bali. Rice tungro is caused by simultaneous infection of two different viruses. C evaluation of antisera produced at irri against rice tungro viruses, and. The information on this website does not warrant or assume any legal liability or responsibility for the accuracy, completeness or usefulness of the courseware contents. They are mainly caused by bacteria, viruses, or fungi. Tungro is caused by rice tungro bacilliform virus rtbv and rice tungro spherical virus rtsv. Performance of rice tungro resistant promising line in. Transmission of rice tungro bacilliform virus rtbv and rice tungro spherical virus rtsv to rice and weeds by nephotettix virescens, n. Tungro means degenerated growth and the virus was first observed in the philippines 1975. A suite of new techniques to tackle the devastating rice losses caused by tungro is now helping smallscale farmers in indonesia, the philippines and india.
Observations in the field showed that there were typical symptoms of tungro infection in rice plants, namely orange leaves starting from leaves to 2 and 3, little tillers, stunted. Weed host range of rice tungro virus disease 385 table 2. Part of this need rests on the global importance of rice to human life. In cytoplasmic male sterile lines a lines where the emergence of the panicles is poor, the incidence of sheath rot is very high.
Weed host range of rice tungro virus disease article pdf available in plant archives 181 june 2018 with 228 reads how we measure reads. This technique can detect the viral dna in fold diluted leaf extract. In this case of rice tungro disease, viral infection is commonly transmitted by the green leafhopper. Tungro infected plants are stunted, yellowing and significant yield losses. Watch this video to learn about the diseases in rice crop, the symptoms, causes and the ways of controlling them. Rice tungro disease rtd consists of a spherical virus rtsv and a bacilliform virus rtbv and the disease is a significant yield constraint in ricegrowing areas of south and southeast asia. Rice tungro is a complex disease caused by rtbv rice tungro bacilliform virus and rtsv rice tungro spherical virus hibino et al. Rice tungro disease, caused by rice tungro spherical virus and rice tungro bacilliform virus. Rice tungro disease is caused by a complex of two viruses, rice tungro bacilliform virus rtbv and rice tungro spherical virus rtsv. Jan 09, 2020 nucleotide sequence and genomic organization of rice tungro spherical virus.
Like many other rice virus, the tungro disease is transmitted by vector. Screening of hybrid and inbreed rice varieties against tungro. Rtbv has a bacilliform capsid or bulletshaped particles x 30 nm made up of a single piece of the coat protein of mw 36 k and a single molecule of circular ds dna of 8. Among the three leaves and neck infections are more severe. Motschulsky were collected with sweep rice virus diseases were surveyed in the philippines from november 1983 to march 1985. Tungro virus disease is transmitted by leafhoppers, wherein the most efficient vector is the green leafhopper, nephotettix virescens distant. Rice tungro spherical virus strain a rtsv rice tungro. Grain discolouration of rice has become a serious problem in recent years especially when there is postflowering rain. Symptoms of tungro include orange yellow coloring of leaves, stunting, reduction in tiller number, and poor panicle emergence.
Virus diseases of rice rice tungro virus y asuo saito 11, hirovuki hibin0 21, toshihiro omura 31, and h. A mathematical model of transmission of rice tungro disease by. Dry rot is firm or dry decay, while soft rot is soft, watery decomposition. Rice tungro disease rtd is one of the most destructive diseases of rice in south and southeast asia. The biology, epidemiology, and management of rice tungro. Rice tungro bacilliform virus rtbv bacilliform capsid, circular ds dna genome and rice tungro spherical virus rtsv isometric capsid ss rna genome. What it does rice tungro disease is caused by the combination of two viruses, which are transmitted by leafhoppers. Diseases of rice and their management year3 youtube. To prevent serious outbreaks, detection of tungro disease. Rice tungro disease rtd is one of the most destructive diseases of rice in tropical asia hibino et al. Tungro is a composite disease caused by rice tungro bacilliform virus rtbv and rice tungro spherical virus rtsv see respective data sheets for each virus and has a complex epidemiology hibino et al. Information is given on the geographical distribution in asia, bangladesh, brunei darussalam, china, fujian, guangdong, hainan, hubei, hunan, jiangxi, shandong, india, andhra pradesh, assam, bihar, delhi, karnataka, kerala, madhya pradesh, manipur. Ditylenchus angustus ufra disease tylenchina anguinidae current list cpc 2007 list 17 meloidogyne oryzae, m.
Testing of weed host species against rice tungro disease under glass house conditions. It is a composite disease caused by two morphologically unrelated viruses. Tungro is one of the most serious rice diseases in south and southeast asia. Rtsv resistance found in traditional cultivars has contributed to a reduction in the incidence of rtd in the field. Contribution of downstream promoter elements to transcriptional regulation of the rice tungro bacilliform virus promoter, nucleic acids research, 2002, pp. Rice tungro disease rtd consists of a spherical virus rtsv and a bacilliform virus rtbv and the disease is a significant yield constraint in rice growing areas of south and southeast asia. Studies on the incidence of ricetungro virus rtv and. Pdf on feb 1, 2002, osmat azzam and others published the biology, epidemiology, and management of rice tungro disease in asia find. Green leafhopper adults tungro disease affected rice field both nymphs and adults suck the sap from the leaves and tillers with their sucking mouth parts resulting yellowing of the leaves which later become brown and dry up from the tip downwards. It is known there are two coinfected virus transmitted by nephotettix virescens. Based on the new understanding that tungro is a composite disease caused by rice tungro bacilliform virus rtbv and rice tungro spherical virus rtsv hibino et al. Occurrence and spread of rice tungro spherical virus in. A rapid technique was developed to detect rtbv dna in the crude extract of freshly collected leaf samples by polymerase chain reaction pcr.
Diseases of field crops and their management pdf book. Here we report the development of two serological based assays for ease of detection. Recovering ability of upland and rainfed lowland rice varieties against rice tungro disease. Pdf the biology, epidemiology, and management of rice tungro. The disease complex is associated with rice tungro baciliform virus rtbv and rice tungro spherical virus rtsv. Most of rice diseases occur in asia and those diseases are related to climatic situation 3. Rice tungro bacilliform virus rtbv having a double stranded circular dna genome and rice tungro spherical virus rtsv having a single stranded rna genome. Sep 19, 2009 rice tungro disease rtd, caused by the coinfection of rice tungro bacilliform virus rtbv and rice tungro spherical virus, is one of the most important viral diseases of rice in south and southeast asia. Among these, rice tungro disease rtd causes severe disruption of rice production, affecting more than 350 000 ha throughout the main rice. As the most important of the 14 rice viral diseases, tungro was first recognized as a leafhoppertransmitted virus disease in 1963 88.
Rice productivity through integration of stress tolerant rice varieties and improved nutrient management practices in saline areas of bangladesh 91 m t khatun, m a latif, m m rahman, m hossain, t h ansari, b nessa, m a i khan, m a ali and m m hanafi. Tungrovirus is a genus of viruses, in the family caulimoviridae order ortervirales. Rtsv resistance found in traditional cultivars has contributed to a. Suppression of symptoms of rice tungro virus disease by carbendazim. Transgenic rice plants that overexpress transcription. Present status of rice tungro disease in west bengal. Technology identified could reduce the spread of rice. Rtbv open reading frame 3 is predicted to encode a capsid protein, protease pr, and reverse transcriptase rt and has the capacity to encode other proteins of as yet unknown function. Virus detection is done by loopmedated isothermal amplification lamp. This disease caused severe outbreak periodically in many rice growing countries including india. Occurrence and spread of rice tungro spherical virus in the philippines. Yield losses due to tungro are primarily due to infection with rtbv. Stunting of the plant along with yellowish or orange discoloration and twisting of the leaves leaf blade, reduced tillering, delayed flowering etc. Tungro virus disease is one of the most devastating and wide spread diseases of rice.
The disease is caused by rice tungro virus rtv, which is transmitted by the green leafhopper, nephotettix virescens. To examine the rnaibased defence response in rice during tungro disease, we characterized the virusderived small rnas and mirnas by deep sequencing. Preventing the occurrence and spread of this virus could result in increased yields ranging from five to 10 percent annually in affected areas. Disease symptoms are caused largely by infection by the rice tungro bacilliform virus rtbv. Common insect pests of rice and their natural biological control an illustrated guide to the insect pests that feed on rice plants and the organisms that feed. Disease cycle transmission mainly by the leaf hopper vector nephotettix virescens males, females and nymphs of the insect can transmit the disease. It may be circular, angular, or irregular in shape. Oct 20, 2017 tungro disease caused by rice tungro spherical virus rtsv and rice tungro bacilliform virus rtbv was first recorded in 1966 in bangladesh and reported as the most damaging viral disease. In 1975, rtbv was first recognized and then identified as a component member along with rice tungro spherical virus rtsv of the virus complex that is responsible for causing rice tungro disease. Rtsv causes no clear symptoms or very mild stunting of plants hibino, 1983a. Rice tungro spherical virus resistance into photoperiod. Decrease in yield will eventually effect the decrease in profit for sure, thus will lower the productivity.
The populations were reared on ir64 for eight generations and tested on six cultivars, including susceptible tn1, moderately resistant ir26 and ir36, and resistant ir54, ir62, and ir64. From identification to disease control article pdf available in world applied sciences journal 316. Rice tungro, a vectorborne virus disease, is one of the most serious biotic constraints to rice production in south and southeast asia. Pathogen two morphologically unrelated viruses present in phloem cells. There are periodic largescale epidemics of tungro which cause significant economic losses and more localised epidemics which also have a severe impact on farmers livelihoods. Production of tungro resistant cul ti vars is a major breeding objective. Characterization of the protease domain of rice tungro. Uploaded files international rice research institute. Rtbv cannot be transmitted by leafhoppers unless rtsv is present. Plant nigropictus stl, and recilia dorsalis disease 70. Novel alleles of rice eif4g generated by crisprcas9. Beachya,1 adonald danforth plant science center, 975 north warson road, st. The use of varieties resistant to the tungro disease effectively prevent an explosion tungro disease. An outbreak of rice tungro disease was noticed during kharif 2007 in telangana region of andhra pradesh, india.
Rice tungro disease is caused by an rna and a dna virus. The lack of resistance genes to rtbvthe causal agent of tungro diseasemakes it even. Genetic engineering of rice to resist rice tungro disease. Biological control of rice tungro disease rtd springerlink.
As the most important of the 14 rice viral diseases, tungro was first recognized as a leafhoppertransmitted virus disease in. The timely detection and applying effective actions is a challenging aspect of disease control 4. Information is given on the geographical distribution in asia. Rice tungro bacilliform virus rtbv 10, 11, a member of the genus badnavirus in the family caulimoviridae, and rice tungro spherical virus rtsv, a singlestranded rna virus and member of the genus waikivirus in the family. The investigator can vary individual or combined factors among the cages to determine their effects on percentage of infection of the test seedlings. Rice tungro bacilliform virus rtbv and rice tungro spherical virus rtsv. The disease remains one of the major threats to sustainable rice production in many countries. A characterization of rice tungro epidemics in the. Journal common insect pests of rice and their natural. Tungro infects cultivated rice, some wild rice relatives and other grassy weeds commonly found in rice paddies. Rice tungro disease rtd is a serious constraint in rice production across tropical asia. Rice varieties and advanced breeding lines evaluated for resistance to leafhopper vectors and to tungro viruses at two locations in each of the three countries india, indonesia and philippines and recommended for deployment in specific localities to provide durable resistance to rtvd. Integrated management of rice tungro disease in south sulawesi. Better understanding of the leafhopper insect that spreads the virus has led to better growing practices, especially late.
Weed species presence symptoms expressed due to rtd virus recovery from the weeds of virus sshowing positive reaction 1. The purpose of this chapter is to introduce the reader to the major or devastating diseases of rice. Rice tungro is a composite disease caused by joint infection of two unrelated viruses, rice tungro bacilliform virus rtbv and rice tungro spherical virus rtsv, appears in the form of severe yellowing and stunting in susceptible rice. Tungro virus disease of rice has been a serious problem in rice. It is found to occur in ortyza sativa and ortyza sp. We used historical survey data to compare patterns of rice tungro epidemics in two endemic areas and one nonendemic area in the philippines. Small specks originate on leaves subsequently enlarge into spindle shaped spots0. The biology, epidemiology, and management of rice tungro disease in asia. The occurrence of the disease is sporadic in nature and it can appear at any time from seedling stage to reproductive phase. Bakanae disease is an important fungal disease caused by gibberella fujikuroi.
Rtd is routinely detected based on visual observation of the plant. Technology identified could reduce the spread of rice virus. The effort to increase rice production is often constrained by outbreaks of viral diseases. Oct 18, 2004 endogenous rice tungro bacilliform virus rtbvlike sequences ertbvs have been found throughout the rice genome. Feb 28, 2018 what it does rice tungro disease is caused by the combination of two viruses, which are transmitted by leafhoppers. A characterization of rice tungro epidemics in the philippines from historical survey data. Population characteristics and tungro transmission by. Major outbreaks of tungro have been occurred in countries of south and southeast asia, mediated by a viral carrier green leafhopper. Reconstruction of putative dna virus from endogenous rice.
Spot a spot is a localized necrotic or dead area photo 4. Pdf as the most devastating viral disease of rice in south and southeast asia, rice tungro disease remains one of the significant fears to. Farmers lose an estimated average of 37% of their rice crop to pests and diseases every year. Rice tungro disease perhaps the most important disease affecting rice is rice tungro disease rtd. Rice tungro disease is the major constraint, caused by a combination of rice tungro spherical virus rtsv and rice tungro bacilliform virus rtbv. Beating tungro virus disease in rice riu validated rnrrs output. The success of a monitoring system can be measured by its ability to provide early detection of pests for prevention of a serious outbreak of rice tungro. Rice tungro disease is caused by the combination of two viruses, which are transmitted by leafhoppers. Tungro is polycyclic and complex disease of rice associated by dual infection with rice tungro bacilliform virus rtbv and rice tungro spherical virus rtsv.
Rtd is caused by rice tungro bacilliform virus rtbv and rice tungro spherical. Rice tungro spherical virus rtsv is transmitted in a semipersistent. In india, it can cause an estimated loss of 2% at the national level. Protect japanese rice cultivation from tropical rice. Rice tungro bacilliform virus rtbv is a newly described badnavirus and proposed member of the plant pararetrovirus group.
Disease such blast and rust, bacterial blight and stem rot are the most dangerous disease that gives economic damage to paddy. Transgenic rice plants that overexpress transcription factors rf2a and rf2b are tolerant to rice tungro virus replication and disease shunhong daia,1, xiaoping weia, antonio a. Tungro virus disease is transmitted by leafhoppers, wherein the most efficient vector is the green leafhopper,nephotettix virescens distant. Suppression of symptoms of rice tungro virus disease by. This disease is one of the major rice virus diseases and an important potential threat to rice production in this area due to its occasional severe outbreaks. Rice green leafhopper nephotettix virescens distant populations were collected in 1985 from fields planted with a leafhopper resistant rice, oryza sativa cultivar ir64 in south cotabato, philippines. Rtd is caused by the interaction between rice tungro spherical virus rtsv and rice tungro bacilliform virus. Small rnabased interactions between rice and the viruses. Rice tungro disease rtd is one of the destructive and prevalent diseases in the tropical region. Rice tungro bacilliform virus rtbv together with rice tungro spherical virus rtsv is the causal agent for the rice tungro disease. It destroys the rice grain which is an interested part to be harvest. Virusvector composition analysis in rice tungro virus.
The biology, epidemiology, and management of rice tungro disease in asia article pdf available in plant disease 862. It is caused by a complex of two viruses saito et al. Incidence of rice bakanae disease creates serious problems in the foremost rice growing countries, and no rice variety has been found to be completely resistant to this disease. Pdf files for printing pdf file size approximate download time over a 56k modem. Oryza sativa rice tungro rice tungro bacilliform virus rice tungro spherical virus. Apart from direct feeding both nymphs and adults act as vectors of rice tungro virus disease. It causes leaf discoloration, stunted growth, reduced tiller numbers and sterile or partly filled grains. Planting a resistant variety is the simplest and, often, the most cost effective management for diseases. Disease can infect paddy at all growth stages and all aerial parts of plant leaf, neck and node. Deteksi virus tungro pada padi di bengkulu sutrawati. Diagnosis of common diseases of rice home irri rice.
Previously, the causal agent of the disease was thought to be rice tungro virus, a spherical virus about 30nm in diameter. Many farmers in south and southeast asia describe rice tungro disease as a cancer disease because of the severe damage it causes and the difficulty of controlling it 121. Rtd is caused by rice tungro spherical virus rtsv and rice tungro bacilliform virus. A new distribution map is provided for rice tungro disease viruses hosts. Development of an indirect elisa and dotblot assay for. Here, we reconstructed putative virus structures from rtbvlike sequences in the rice genome and characterized to understand evolutionary implication, integration manner and involvements of endogenous virus segments in the. However, it is not always easy to identify the disease in the field as it is often confused with other diseases or physiological disorders.
High concentrations of carbendazim bavistin wp markedly reduced leaf chlorosis, stunting, and decreased number of tillers by tungro virus disease in rice plants. Apr 30, 2018 rice tungro disease rtd is a serious constraint in rice production across tropical asia. This is a leafhopper cicadellidae, nephotettix spp. However, breeding rice varieties resistant to bakanae disease may be a costsaving solution preferable to the application of fungicides. Rotting is disintegration and decomposition of host tissue photo 3. Rice tungro bacilliform virus encodes reverse transcriptase. Tungro disease viruses are transmitted from one plant to another by leafhoppers that feed on tungro infected plants. After reading these icar ecourse, please give your feedback for improve of the ecourse contents on this website. Combining genes that overexpress rf2a and rf2b with genes that provide resistance to the insect vector could generate new rice varieties with significantly improved resistance to rice tungro disease in vulnerable regions in the world. Monocots and family poaceae serve as natural hosts.
In this study a tungro disease survey was conducted in several areas in bengkulu province. Apr 14, 2005 rice tungro is a major rice disease in southeast asia and is caused by a double infection by two viruses 8, 9. The most important rice virus disease is tungro that transmit through green leafhopper. Fine mapping of qbk1, a major qtl for bakanae disease. Prevention of rice tungro virus disease and control of the vector with.