In view of the above facts the present study was conducted to investigate the incidence level of tungro disease and to know the most susceptible growth stage of rice due to this disease in mostly cultivated hybrid and inbreed varieties in bangladesh. Rice can be puffed under low pressure to produce puffed rice that is commonly used as a breakfast cereal. Rtd is routinely detected based on visual observation of the plant. Rtd is a composite virus disease transmitted mainly by the green leafhopper glh, nephotettix virescens. Evaluation of systemic insecticides for control of rice tungro. Rice tungro disease is caused by the combination of two viruses, which are transmitted by leafhoppers. The first and only genome of rice tungro bacilliform virus rtbv isolated from rice in malaysia was sequenced in 1999. The disease complex is associated with rice tungro baciliform virus rtbv and rice tungro spherical virus rtsv. Prevention of rice tungro virus disease and control of the. Transgenic rice plants that overexpress transcription.
Green leafhoppers glh that have acquired the viruses rice tungro bacilliform virus or rtbv and rice tungro sperical virus or rtsv after feeding on infected plants, stubbles or volunteer rice in nearby fields infected seedlings transplanted in the field new growth from infected stubbles not effectively plowed under. Rice tungro viruses are transmitted by leafhoppers. Consequently, the additional outputs and their associated. Dec 30, 2008 rice tungro disease rtd is a significant yield constraint in rice growing areas of south and southeast asia. 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. A new distribution map is provided for rice tungro disease viruses hosts. Rf2b, a rice bzip transcription activator, interacts with rf2a and is involved in symptom development of rice tungro disease shunhong dai, zhihong zhang, shouyi chen, and roger n. Rotting is disintegration and decomposition of host tissue photo 3. Tungro virus disease is transmitted by leafhoppers, wherein the most efficient vector is the green leafhopper, nephotettix virescens distant. In india, it can cause an estimated loss of 2% at the national level. Rice tungro disease was found to be associated with a virus complex composed of two different viruses and these viruses were described as rice tungro spherical virus rtsv and rice tungro bacilliform virus rtbv.
Rice tungro disease was discovered in malaysia in the 1930s. Suppression of symptoms of rice tungro virus disease by carbendazim. 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. It is a composite disease caused by two morphologically unrelated viruses. The tungro epidemiological model developed in this study is named rtdsim rice tungro disease simulation and is created in the r programming language r version 3. Kedua jenis virus tersebut tidak memiliki kekerabatan serologi dan.
Spot a spot is a localized necrotic or dead area photo 4. It is caused by a complex of two viruses saito et al. 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. Prevention of rice tungro virus disease and control of the vector with. Rice tungro bacilliform virus an overview sciencedirect. Gene expression analysis of rice genotypes during rice tungro virus infection on free shipping on qualified orders.
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. Beating tungro virus disease in rice riu validated rnrrs output. Information is given on the geographical distribution in asia. Of seven granular systemic insecticidescarbaryl plus gamma isomer of hexachlorocyclohexane hch, carbofuran, disulfoton, fensulfothion, mephosfolan, phorate, and thiodemetontested under field conditions, carbofuran at 2 kg a. Development of an indirect elisa and dotblot assay for. Rice tungro disease rtd is one of the most destructive diseases of rice in south and southeast asia. After nearly two decades, here, we present the complete genome sequence of an rtbv isolate in rice from seberang perai, malaysia. Suppression of symptoms of rice tungro virus disease by. Present status of rice tungro disease in west bengal. Rice tungro bacilliform virus was first described by saito in 1975. The disease is caused by rice tungro virus rtv, which is transmitted by the green leafhopper, nephotettix virescens. Apart from direct feeding both nymphs and adults act as vectors of rice tungro virus disease. Development of a rice tungro epidemiological model for. Tungro infects cultivated rice, some wild rice relatives and other grassy weeds commonly found in rice paddies.
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. Sphaerulina oryzina teleomorph pecky rice kernel spotting damage by many fungi including. Rice tungro is one of the most destructive viral disease particularly in north eastern and eastern coastal regions of peninsular india. Summary rice tungro disease rtd is a serious constraint in rice production across tropical asia. 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. After nearly two decades, here, we present the complete genome sequence of an rtbv isolate in.
Disease symptoms are caused largely by infection by the rice tungro bacilliform virus rtbv. Rice tungro disease rice tungro virus rtsv, rtbv brown spot helminthosporium oryzae sheath rot sarocladium oryzae sheath blight rhizoctonia solani false smut ustilaginoidea virens grain discolouration fungal complex leaf streak xanthomonas oryzae pv. Symptoms of tungro include orange yellow coloring of leaves, stunting, reduction in tiller number, and poor panicle emergence. Disease cycle transmission mainly by the leaf hopper vector nephotettix virescens males, females and nymphs of the insect can transmit. Summary comparative transmission by leafhoppers of three tungro isolates obtained from. Beachya,1 adonald danforth plant science center, 975 north warson road, st. It is found to occur in ortyza sativa and ortyza sp. Two host transcription factors, rf2a and rf2b, regulate expression of the rtbv promoter and are important for plant development. Rf2b, a rice bzip transcription activator, interacts with.
Staggered planting under the doublecropping rice systems is the major reason why tungro disease predominated after the 1960s. We present evidence that rice tungro spherical virus rtsv has a genome of polyadenylated singlestranded rna of about 10 kb whereas rice tungro bacilliform virus rtbv contains doublestranded circular dna. It causes leaf discoloration, stunted growth, reduced tiller numbers and ste. Tungro wikipedia bahasa indonesia, ensiklopedia bebas.
Rtbv cannot be transmitted by leafhoppers unless rtsv is present. Rice tungro bacilliform virus rtbv bacilliform capsid, circular ds dna genome and rice tungro spherical virus rtsv isometric capsid ss rna genome. The purpose of this chapter is to introduce the reader to the major or devastating diseases of rice. Of all viral diseases on rice, tungro disease is the most economically devastating in south and. Rtbv dna has been mapped and shown to have two discontinuities, one in each strand, at specific sites. Plants affected by tungro exhibit stunting and reduced tillering. Rice tungro, the most important virus disease of rice in south and southeast asia, is caused by a complex of two viruses, rice tungro bacilliform virus rtbv and rice tungro spherical virus rtsv. Pdf as the most devastating viral disease of rice in south and southeast asia, rice tungro disease remains one of the significant fears to. Rtbv is a plant pararetrovirus with bacilliform particles, the structure of which is based on t 3 icosahedral symmetry cut across the threefold axis. Division of plant pathology, central rice research institute, cuttack.
Based on field evaluation trial and greenhouse reaction, the rice cultivars cr1467003, cr 260157, cr 2606321 and cr 319644 had high degree of resistance to tungro with high yielding ability. Rice tungro disease rtd is one of the viral diseases which devastated rice production in south and southeast asia. Experimental epidemiology of rice tungro disease we studied the effects of several factors on tungro incidence in terms of percent age of infected seedlings of the variety taichung native 1 tnl by the cage method in a greenhouse. The initial lesions are small, ellipsoid or ovoid, and greenishgray photo. Green leafhoppers glh that have acquired the viruses rice tungro bacilliform virus or rtbv and rice tungro sperical virus or rtsv after feeding on infected plants, stubbles or. Rnainterference in rice against rice tungro bacilliform virus results. Fourteen rice cultivars were identified as field resistant. The disease results from an infection by two distinct viruses, rice tungro bacilliform virus rtbv and rice tungro spherical virus rtsv 5,6. Tungro virus disease of rice has been a serious problem in rice. The biology, epidemiology, and management of rice tungro. Rice tungro disease, the most important viral disease of rice, is widespread in south and southeast asia and is believed to be responsible for. Beachy the donald danforth plant science center, 975 north warson road, st. Dry rot is firm or dry decay, while soft rot is soft, watery decomposition.
Novel alleles of rice eif4g generated by crisprcas9. Oryza sativa rice tungro rice tungro bacilliform virus rice tungro spherical virus. The tungro virus is known to have at least two strains s and m. Satapathy division of plant pathology, central rice research institute, cuttack.
Tungro is a disease complex associated with rice tungro bacilliform rtbv and spherical. Rice starch can be extracted and fermented to produce rice wine or brewed to produce sake. Rice tungro disease rtd is very common in most rice growing areas, especially in the philippines, and it inflicts severe damage on rice fields savary et al. Due to the severity of the rtd, close monitoring of this disease is important to ensure the disease does not become widespread and could have a disastrous effect to the paddy fields and farmers. 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.
Prevention of rice tungro virus disease and control of the vector with granular insecticides m. Symptoms the lesions are usually observed on the leaf sheaths although leaf blades may also be affected. Complete genome sequence of rice tungro bacilliform virus. Here we report the development of two serological based assays for ease of detection. Complex virus rtbv and rtsv transmitted by green leafhopper nephotettix spp. In this report we describe some molecular properties of the two viruses. Biological control of rice tungro disease rtd springerlink. Tungro became a serious problem after the release of highyielding rice cultivars which are short statured and photoinsensitive, have shorter growth duration, and allow rice growers two crops of rice in a year. Diagnosis of common diseases of rice home irri rice. Tungro virus disease affects all growth stages of the rice plant specifically the vegetative stage. Of seven granular systemic insecticidescarbaryl plus gamma isomer of hexachlorocyclohexane hch, carbofuran, disulfoton, fensulfothion, mephosfolan, phorate, and thiodemetontested under field conditions, carbofuran at.
Pdf the biology, epidemiology, and management of rice. The viruses are common in mixed infections in south and south. Vector species of the disease, transmission efficiencies of the disease by vectors and. Tungro disease viruses are transmitted from one plant to another by leafhoppers that feed on tungro infected plants.
Screening of hybrid and inbreed rice varieties against. However, it is not always easy to identify the disease in the field as it is often confused with other diseases or physiological disorders. Green leafhoppers glh that have acquired the viruses rice tungro bacilliform virus or rtbv and rice tungro sperical virus or rtsv after feeding on infected plants, stubbles or volunteer rice in nearby fields. 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 cultivars.
The 15 known viruses that occur in rice are rice blackstreaked dwarf, rice bunchy stunt, rice dwarf, rice gall dwarf, rice giallume, rice grassy stunt, rice hoja blanca, rice necrosis mosaic, rice ragged stunt, rice stripe necrosis, rice stripe, rice transitory yellowing, rice tungro bacilliform, rice tungro spherical, and rice yellow mottle viruses. 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. Rice tungro bacilliform virus rtbv and rice tungro spherical virus rtsv. 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. Comparative transmission of, and varietal reaction to, three isolates. As the most important of the 14 rice viral diseases, tungro was first recognized as a leafhoppertransmitted virus disease in. The virus withstands temperatures below 63degree celsius for 10 minutes. The biology, epidemiology, and management of rice tungro disease in asia. Integrated management of rice tungro disease in south sulawesi. Rice bran oil can be produced from the inner husk and can be used as a cooking oil. Of these, rice tungro virus disease is wide spread and occurred in epidemic form in several states of india and gained considerable importance during the last 50 years.
Tungro penyakit tungro disebabkan oleh dua jenis virus yang berbeda yaitu virus bentuk batang rice tungro bacilliform virus rtbv dan virus bentuk bulat rice tungro spherical virus rtsv. Tungro disease is caused by coinfection of two different viruses, rice tungro bacilliform virus rtbv, genus tungro virus, family caulimoviridae a. What it does rice tungro disease is caused by the combination of two viruses, which are transmitted by leafhoppers. Rice tungro, which means degenerated growth in a philippine dialect, is a devastating disease caused by coinfection with two morphologically and genetically different viruses, rice tungro spherical virus rtsv and rice tungro bacilliform virus rtbv, depicted in fig. Galves 1968 purified the virus and reported that the particles are polyhedral with a diameter of 3033 nanometers.
It causes leaf discoloration, stunted growth, reduced tiller numbers and sterile or partly filled grains. Additional outputs 47 resulting from subsequent amendments to the project memorandum were closely linked to outputs. 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. Transgenic rice plants that overexpress transcription factors. Discoloration begins from leaf tip and extends down to the blade or the lower leaf portion.
Their leaves become yellow or orangeyellow, may also have rustcolored spots. Identification of field resistant rice cultivars for. It may be circular, angular, or irregular in shape. Rtd is caused by the interaction between rice tungro spherical virus rtsv and rice tungro bacilliform virus. Nri final technical report the epidemiology and management of. Better understanding of the leafhopper insect that spreads the virus has led to better growing practices, especially late. High concentrations of carbendazim bavistin wp markedly reduced leaf chlorosis, stunting, and decreased number of tillers by tungro virus disease in rice plants. Prevention of rice tungro virus disease and control of the vector with granular insecticides. Rice tungro spherical virus rtsv is transmitted in a semipersistent. It calculates the rate of rice hill infection or how many rice hills are infected with rice tungro virus through its vector, green leafhopper glh, based on weather conditions over the. 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. Rice diseases and pests, description, uses, propagation. Kedua jenis virus tersebut tidak memiliki kekerabatan serologi dan dapat menginfeksi tanaman secara bersamasama.
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