Tomato spotted wilt and peanut bud necrosis viruses

The peanut bud necrosis virus (PBNV) nd tomato spotted wilt virus (TSWV), both tospoviruses, cause economically important diseases in peanut..

Peanut stripe virus - a new seed-borne potyvirus from China infecting groundnut (Arachis hypogaea)

A new virus, peanut stripe (PStV), isolated from groundnut (Arachis hypogaea) in the USA, induced characteristic striping, discontinuous vein banding along the lateral veins, and oakleaf mosaic in groundnut. The virus was also isolated from germplasm lines introduced from the People's Republic of China. PStV was transmitted by inoculation of sap to nine species of the Chenopodiaceae, Leguminosae, and Solanaceae; Chenopodium amaranticolor was a good local lesion host. PStV was also transmitted by Aphis craccivora in a non-persistent manner and through seed of groundnut up to 37%. The virus remained infective in buffered plant extracts after diluting to 10-3, storage for 3 days at 20°C, and heating for 10 min at 60°C but not 65°C. Purified virus preparations contained flexuous filamentous particles c. 752 nm long, which contained a major polypeptide of 33 500 daltons and one nucleic acid species of 3·1 × 106 daltons. In ELISA, PStV was serologically related to blackeye cowpea mosaic, soybean mosaic, clover yellow vein, and pepper veinal mottle viruses but not to peanut mottle, potato Y, tobacco etch, and peanut green mosaic viruses. On the basis of these properties PStV is identified as a new potyvirus in groundnut

Identification and Incidence of Peanut Viruses in Georgia

Surveys of peanuts in Georgia in 1983 detected peanut mottle virus (PMV), peanut stripe virus (PStV), and peanut stunt virus. The mild strain of PMV was by far the most prevalent virus in commercial peanuts; it occurred in every field and an average incidence of 15-20% was observed when the growing season was about two-thirds complete. The necrosis strain of PMV was noted in 39% of the fields, but the incidence was less than 0.1%. A new severe strain of PMV (chlorotic stunt) was identified in two fields. PStV was found at four locations; in each case the infected plants were near peanut germplasm lines from The People's Republic of China. Mixed infections of PMV and PStV occurred frequently. Peanut stunt virus was noted only in one research field in 1983. Numerous serological and sap inoculation tests did not detect tomato spotted wilt virus or cowpea chlorotic mottle viru

Purification and some serological relationships of tomato spotted wilt virus isolates occurring on peanut (Arachis hypogaea) in the USA

A procedure for the purification of TSWV-Tx, a tomato spotted wilt virus isolate infecting groundnuts in Texas, is described. A rabbit antiserum was produced. Several TSWV isolates occurring on groundnuts in the USA reacted to varying extents in ELISA with antisera to TSWV-Tx and to Greek TSWV isolates, but failed to react with antiserum to an isolate of TSWV from India. In reciprocal tests, antigens of the Indian TSWV failed to react with antisera to Tx and to the Greek isolates. Purified TSWV-Tx contained 4 polypeptide species of 78 000, 54 000 and 27 000 Da. In electro-blot immunoassays, all 4 polypeptides reacted with the homologous antiserum and with antisera prepared against a Greek, a Dutch and an Australian isolate. None of the polypeptides reacted with the antiserum to the Indian isolate

Search for a periodic signal from Cygnus X-3 usingmuons observed underground in the Frejus detector (4800 mwe)

Periodic signals from Cygnus X-3 in the ultra high energy range were recently reported by air shower arrays and attributed to gamma rays. Although gamma rays are expected to produce muon-poor showers, the preceding observations have stimulated similar studies based on underground muons. Two groups have claimed a significant underground signal coming from Cygnus X-3. The results are, however, extremely difficult to explain in the present framework of particle physics, and clearly need confirmation. The preliminary results obtained from the Frejus underground detector during its first 16 months of operation (March 1984 to June 1985) are presented

Viruses associated with chlorotic rosette and green rosette diseases of groundnut in Nigeria

Groundnut (Arachis hypogaea) plants from Nigeria with chlorotic rosette disease contained a manually transmissible virus, considered to be a strain of groundnut rosette virus (GRV(C)). GRV(C) infected nine out of 32 species in three out of nine families. It caused local lesions without systemic infection in Chenopodium amaranticolor, C. murale and C. quinoa, and systemic symptoms in Glycine max, Nicotiana benthamiana, N. clevelandii and Phaseolus vulgaris as well as in groundnut. Some ‘rosette-resistant’ groundnut lines were also infected. GRV(C) was transmitted by Aphis craccivora, but only from groundnut plants that were also infected with an aphid-transmissible second virus, which was not manually transmissible and was considered to be groundnut rosette assistor virus (GRAV). Plants infected with GRAV contained isometric particles c. 25 nm in diameter which were detectable by immunosorbent electron microscopy on grids coated with antisera to several luteoviruses, especially with antisera to bean leaf roll, potato leafroll and beet western yellows viruses. No virus-like particles were observed in extracts from plants infected with GRV(C) alone. A single groundnut plant obtained from Nigeria with symptoms of green rosette contained luteovirus particles, presumed to be of GRAV, and yielded a manually transmissible virus that induced symptoms similar to those of GRV(C) in C. amaranticolor but gave only mild or symptomless infection of N. benthamiana and N. clevelandii. It was considered to be a strain of GRV and designated GRV(G)

Field Diagnosis of Groundnut Diseases

Diseases ar e major constraints to groundnut production throughout the world. This handbook is designed to assist agricultural research and extension workers, wh o may have little formal training in plant pathology, to make tentative diagnosis of diseases of groundnut caused by 31 fungi, 2 bacteria. 9 viruses, a mycoplasma-like organism, 4 nematodes, and a parasitic flowering plant. The most characteristic field symptoms of each disease are Illustrated and descr ibed. It is emphasized that for confirmation of field diagnosi s the assistance of skilled plant pathologists will be requi red in most cases

Bud Necrosis: A Disease of Groundnut Caused by Tomato Spotted Wilt Virus

This is the first ICRISAT Information Bulletin that deals with a virus disease of groundnut. Attention is focused on bud necrosis disease, caused by tomato spotted wilt virus, because of its economic significance on three continents. Epidemics build up rapidly with little warning and cause serious losses to growers. Protocols for purification and identification of the virus are given in detail. The symptoms of the disease in groundnut are illustrated. Procedures for a simple enzyme-linked immunosorbent assay for the detection of the virus are given. The identification of the vector insects—species of Thysanoptera (thrips)—is difficult, and is still to be fully resolved. But a key is provided as an aid in identifying seven thrips species that have been implicated as vectors of tomato spotted wilt virus on groundnut. The current situation concerning management of bud necrosis disease is outlined. Suitable insecticides, cultural practices, biological control, and host-plant resistance are discussed to assist crop protection and extension workers in formulating integrated management systems appropriate to their particular situations

The complete nucleotide sequence and genome organization of the M RNA segment of peanut bud necrosis tospovirus and comparison with other tospoviruses

The M RNA of peanut bud necrosis tospovirus is 4801 nucleotides in length. It comprised 2 ORFs in an ambisense organization and terminal inverted repeats. The 3 prime large ORF (3363 nucleotides in the virus-complementary strand) encoded a protein with a predicted size of 127.2 kDa which was identified as the glycoprotein precursor (GP) of the G1 and G2 glycoproteins. A comparison of the deduced amino acid sequence of GP revealed 37% identity and 58-59% similarity with that of tomato spotted wilt tospovirus (TSWV,serogroup I) and impatiens necrotic spot tospovirus (INSV, serogroup III) and 21-23% identity and 44-47% similarity with members of the genus Bunyavirus. The 5 prime small ORF (924 nucleotides in the virus-sense strand) encoded a 34.2 kDa protein which was identified as the non-structural (NSm) protein based on 41-43% identity and 60-63% similarity with TSWV and INSV. Defective RNA molecules derived from the genomic M RNA were detected during continuous passage of the virus by sap inoculations

Peanut bud necrosis tospovirus S RNA: complete nucleotide sequence, genome organization and homology to other tospoviruses.

The complete nucleotide sequence of the S RNA of peanut bud necrosis virus (PBNV) has been determined. The RNA is 3 057 nucleotides in length, contains inverted repeats and two open reading frames (ORFs) with an ambisense coding strategy that are separated by an A+U-rich intergenic region. One ORF (1 320 nucleotides in the viral sense strand) encodes a Mr 49.5 kDa protein, identified as the nonstructural (NSs) protein based on similarity to published tospovirus sequences. The second ORF (831 nucleotides in virus complementary strand) encodes a Mr 30.6 kDa protein. This protein was identified as the nucleocapsid (N) protein based on sequence similarities. Amino acid sequence comparison of N and NSs proteins revealed identities of 22-34% with the reported tospovirus isolates of serogroups I, II, and III, whereas it had 82-86% identity with viruses in serogroup IV, watermelon silver mottle virus (WSMV) and tomato isolate of peanut bud necrosis (PBNV-To). Two subgenomic RNA species detected in PBNV infected tissue corresponded to the predicted sizes (1.65 and 1.4 kb) of the NSs and N mRNAs. The data presented show conclusively that PBNV should be included in serogroup IV, along with WSMV and PBNV-To