Maize Mosaic Virus Research Articles

QTL mapping of a partial resistance to the corn delphacid‐transmitted viruses in Lepidopteran‐resistant maize line Mp705

AbstractA partial resistance to maize mosaic virus (MMV) and maize stripe virus (MStV) was mapped in a RILs population derived from a cross between lines MP705 (resistant) and B73 (susceptible). A genetic map constructed from 131 SSR markers spanned 1399 cM with an average distance of 9.6 cM. A total of 10 QTL were detected for resistance to MMV and MStV, using composite interval mapping. A major QTL explaining 34–41% of the phenotypic variance for early resistance to MMV was detected on chromosome 1. Another major QTL explaining up to 30% of the phenotypic variation for all traits of resistance to MStV was detected in the centromeric region of chromosome 3 (3.05 bin). After adding supplementary SSR markers, this region was found to correspond well to the one where a QTL of resistance to MStV already was located in a previous mapping study using an F2 population derived from a cross between Rev81 and B73. These results suggested that these QTL of resistance to MStV detected on chromosome 3 could be allelic in maize genome.

Infection Rates and Comparative Population Dynamics ofPeregrinus maidis(Hemiptera: Delphacidae) on Corn Plants With and Without Symptoms of Maize Mosaic Virus (Rhabdoviridae: Nucleorhabdovirus) Infection

We examined the population dynamics of the corn planthopper Peregrinus maidis (Ashmead) (Hemiptera: Delphacidae) throughout a cycle of corn (Zea mays L.) production on plants with or without symptoms of maize mosaic virus (MMV) (Rhabdoviridae: Nucleorhabdovirus) infection. Our results indicate that the timing of MMV plant infection greatly influenced the planthopper's host plant colonization patterns. Corn plants that expressed symptoms of MMV infection early in the crop cycle (28 d after planting) harbored, on average, 40 and 48% fewer planthoppers than plants that expressed symptoms of MMV infection later in the crop cycle (49 d after planting) and asymptomatic plants, respectively. We also observed a change in the number of brachypterous (short-wing type) and macropterous (long-wing type) winged forms produced; plants expressing early symptoms of MMV infection harbored, on average, 41 and 47% more of the brachypterous form than plants with late infections of MMV and plants with no symptoms of MMV, respectively. Furthermore, we determined the rates of MMV-infected planthoppers relative to their wing morphology (macropterous or brachypterous) and gender. MMV infection was 5 and 12% higher in females than in males in field and greenhouse experiments, respectively; however, these differences were not significantly different. This research provides evidence that MMV similarly infects P. maidis planthoppers regardless of the gender and wing morphotype. These results also suggest that the timing of symptom development greatly affects the population dynamics of the planthopper vector, and likely has important consequences for the dynamics of the disease in the field.

Influence of the Corn Resistance Gene <I>Mv</I> on the Fitness of <I>Peregrinus maidis</I> (Hemiptera: Delphacidae) and on the Transmission of Maize Mosaic Virus (Rhabdoviridae: Nucleorhabdovirus)

Crops that are resistant to pests and pathogens are cost-effective for the management of pests and diseases. A corn (Zea mays L.) breeding program conducted in Hawaii has identified a source of heritable resistance to maize mosaic virus (MMV) (Rhabdoviridae: Nucleorhabdovirus). This resistance is controlled by the gene Mv, which has been shown to have a codominant action. To date, no studies have examined whether the resistance associated with this gene affects only MMV or whether it also affects the insect vector, the corn planthopper Peregrinus maidis (Ashmead) (Hemiptera: Delphacidae). Here, we examined the life history of the corn planthopper and its ability to transmit MMV on near isogenic lines that were homozygous dominant (Mv/Mv), homozygous recessive (mv/mv), or heterozygous (Mv/mv) for the gene. A field trial was also conducted to study the colonization of the corn plants with different genotypes by the planthopper. Although field observations revealed slightly lower densities ofplanthoppers on corn with the genotype Mv/Mv than on the inbreds with the genotype mv/mv and their hybrids with the genotype Mv/mv, laboratory assays showed no effects of the gene on planthopper development, longevity, or fecundity. In the field, the corn lines Mv/Mv had a lower incidence of MMV-infected plants. However, in the greenhouse, the transmission of MMV to corn seedlings did not differ across the near isogenic lines, although the corn lines Mv/Mv showed a delayed onset of symptoms compared with the corn lines mv/mv and Mv/mv. The acquisition of MMV by corn planthoppers on the corn genotypes Mv/Mv and Mv/mv averaged 0.2, whereas the acquisition on the corn genotypes mv/mv averaged > 0.3. Our results show that the Mv gene does not influence the fitness of the planthopper vector, suggesting that it may confer resistance by other means, possibly by limiting virus replication or movement within the host plant.

Influence of a propagative plant virus on the fitness and wing dimorphism of infected and exposed insect vectors

To maximize fitness, plant pathogenic viruses may manipulate their arthropod vectors through direct and indirect (via the host plant) interactions. For many virus-vector-plant associations, insect feeding does not always lead to virus acquisition. In fact, many plant viruses, especially those that propagate into their vectors, are acquired at low rates. Although the majority of insects colonizing an infected plant escape from viral infection, they are still exposed to the indirect effects (i.e. the effect of plant metabolism modification following virus infection). Little information has been reported on the effects of plant viruses on insects that become infected versus those that do not (here referred to as "exposed"). The effect that the Maize mosaic virus (MMV) (Rhabdoviridae) exerts on the fitness and wing dimorphism of the planthopper vector, Peregrinus maidis (Hemiptera, Delphacidae), that developed on leaves from either young or old corn plants was examined. MMV exerted non-consistent to minimal direct effects on developmental time, longevity, nymphal mortality and fecundity. In addition, some small yet significant fitness costs were encountered by exposed planthoppers to escape MMV infection. Furthermore, a significantly higher proportion of macropters over brachypters were produced on MMV-infected old leaves compared with healthy leaves of a similar age. We conclude that the virus influences the dispersal of the vector, promoting a larger production of macropters at the costs of brachypters at a late stage of the plant infection. Because MMV infection in planthoppers did not segregate by wing morphotype, our results indicate that the dispersal of both infected and exposed planthoppers was a likely consequence of the indirect effects of MMV.

Effects of temperature increase on the epidemiology of three major vector-borne viruses

The epidemiologies of Maize streak virus (MSV), Maize stripe virus (MSpV), and Maize mosaic virus (MMV) were compared in La Reunion over a three year-period. Disease incidence caused by each virus was assessed, and the leaf and planthopper vector populations (Cicadulina mbila and Peregrinus maidis) were estimated in weekly sowings of the temperate, virus-susceptible maize hybrid INRA 508 and of the composite resistant cv. IRAT 297. MSV caused the most prevalent disease and MMV the least, with lower incidences in cv. IRAT 297 than in INRA 508. For each plant–virus–vector combination, (a) disease incidence was positively correlated to vector abundance, often with 1 month of time lag; (b) annual periodicity of disease incidence and of vector numbers was consistent with highest autocorrelations and a time lag of 12 months, (c) vector numbers and disease incidence were closely associated with temperature fluctuations, both remaining relatively constant below 24°C and increasing rapidly above this threshold temperature. By contrast, relationships with rainfall and relative humidity (RH) were less consistent. Overall, 63 to 80% of the variance of disease incidence was explained through stepwise regression with vector number, temperature, and sometimes also rainfall or RH. The simple epidemiological model proposed underlines the close link between increased temperature and possible (re-) emergence of these three diseases in a maize cropping area.

Analysis of nucleotide sequence of Iranian maize mosaic virus confirms its identity as a distinct nucleorhabdovirus

The nucleotide sequence of the Iranian maize mosaic rhabdovirus (IMMV) was obtained using a random-PCR method (rPCR) followed by PCR with specific primers. Analysis of the complete nucleotide sequence of the IMMV genes and intergenic regions comprising a total of 12,381 nucleotides (including the partial sequences of leader and trailer regions) revealed six open reading frames (ORF) on the viral complementary RNA (vcRNA). On the basis of its similarities to other rhabdovirus sequences, the IMMV genome consists of 3'-leader-N-P-3-M-G-L-5'-trailer. The intergenic regions contained a characteristic consensus sequence, 3'-AAUUCUUUUUGGGUUU/G-5'. The IMMV gene products showed a high similarity to those of maize mosaic virus and taro vein chlorosis virus and a more distant relationship to other rhabdoviruses. Together with the biological, serological and morphological features described earlier, our molecular data provide evidence that IMMV is a distinct member of the genus Nucleorhabdovirus in the family Rhabdoviridae.

A neurotropic route for Maize mosaic virus (Rhabdoviridae) in its planthopper vector Peregrinus maidis

To investigate the dissemination route of Maize mosaic virus (MMV, Rhabdoviridae) in its planthopper vector Peregrinus maidis (Delphacidae, Hemiptera), temporal and spatial distribution of MMV was studied by immunofluorescence confocal laser scanning microscopy following 1-week acquisition feeding of planthoppers on infected plants. MMV was detected 1-week post first access to diseased plants (padp) in the midgut and anterior diverticulum, 2-week padp in the esophagus, nerves, nerve ganglia and visceral muscles, and 3-week padp in hemocytes, tracheae, salivary glands and other tissues. MMV is neurotropic in P. maidis; infection was more extensive in the nervous system compared to other tissues. A significantly higher proportion of planthoppers had infected midguts (28.1%) compared to those with infected salivary glands (20.4%) or to those that transmitted MMV (15.7%), suggesting the occurrence of midgut and salivary gland barriers to MMV transmission in P. maidis. In this planthopper, the esophagus and anterior diverticulum are located between the compound ganglionic mass and the salivary glands. We postulate that MMV may overcome transmission barriers in P. maidis by proceeding from the midgut to the anterior diverticulum and esophagus, and from these to the salivary glands via the nervous system: a neurotropic route similar to that of some vertebrate-infecting rhabdoviruses.

Registration of 27 Maize Parental Inbred Lines Resistant to Maize Mosaic Virus

Registration of 27 Maize Parental Inbred Lines Resistant to Maize Mosaic Virus

Shotgun sequencing of the negative-sense RNA genome of the rhabdovirus Maize mosaic virus

The maize-infecting nucleorhabdovirus, Maize mosaic virus (MMV), was sequenced to near completion using the random shotgun approach. Sequences of 102 clones from a cDNA library constructed from randomly-primed viral RNA were compiled into a 12,133 nucleotide (nt) contig containing six open reading frames. The contig consisted of 97 sequences averaging 660 bp in length. The average sequence coverage was six-fold, and 93% of the contig had sequence reads covering both strands. The remaining sequence was derived from single (5%) or multiple (2%) reads on the same strand. Three of the six ORFs showed significant similarities to the deduced protein sequences of the nucleocapsid, glycoprotein and polymerase sequences of other rhabdoviruses. The predicted gene order of the MMV genome was 3′ -N-P-3-M-G-L-5′. Shotgun sequencing of the MMV genome took approximately 127 h and cost $ 0.38 per nt (including labor), whereas the primer walking approach for sequencing the 13,782-nt MFSV genome [Tsai, C.-W., Redinbaugh, M.G., Willie, K.J., Reed, S., Goodin, M., Hogenhout, S. A., 2005. Complete genome gequence and in planta subcellular localization of maize fine streak virus proteins. J. Virol. 79, 5304–5314] took about 217 h and cost $ 0.50 per nt. Thus, the shotgun approach gave good depth of coverage for the viral genome sequence while being significantly faster and less expensive than the primer walking method. This technique will facilitate the sequencing of multiple rhabdovirus genomes.

Evaluation of Maize Inbreds for Maize stripe virus and Maize mosaic virus Resistance: Disease Progress in Relation to Time and the Cumulative Number of Planthoppers

ABSTRACT Five tropical maize lines were tested and compared with the susceptible control line B73 for resistance to Maize stripe virus (MStV) and Maize mosaic virus (MMV), both propagatively transmitted by the planthopper Peregrinus maidis (Homoptera: Delphacidae). Resistance to each virus was evaluated separately by artificial inoculations with planthoppers viruliferous for either one virus or the other. Disease incidence and symptom severity progression were quantified in relation to time and the cumulative number of planthoppers. Line Hi40 was found to be susceptible to MStV and highly resistant to MMV. Generally, no MMV symptoms developed on Hi40, even under intense inoculation pressure by a large number of viruliferous planthoppers. Line Rev81 showed a partial but strong resistance to MStV, which mainly reduced disease incidence. Nevertheless, this resistance to MStV was the highest ever reported and held up, even when challenged by large numbers of planthoppers. The percentage of infected plants in line Rev81 never exceeded 30 to 40% in our experiments. Moderate levels of resistance to MStV, and to a lesser extent MMV, were found in lines 37-2, A211, and Mp705. However, resistance in these lines was completely overcome using a large number of insects transmitting either of the two viruses. These results suggest that different types of resistance to MMV and MStV are available in maize lines from Caribbean and Mascarene germ plasm. The expression of virus-specific resistance identified in Hi40 and Rev81 lines was not affected by intense inoculation pressure. In contrast, the moderate resistance in 37-2, A211, and Mp705 was partially effective against both viruses but not at high inoculation pressure. These different types of resistance, when present in the same genotype, could provide protection against both viruses.

Characterization of Maize Iranian Mosaic Virus and Comparison with Hawaiian and Other Isolates of Maize Mosaic Virus (Rhabdoviridae)

AbstractMaize Iranian mosaic virus (MIMV) was characterized and compared with isolates of Maize mosaic virus (MMV, genus Nucleorhabdovirus, family Rhabdoviridae) in insect transmission, cytopathology and ultrastructure of infected maize cells, virion proteins and serologically. MIMV is naturally transmitted by Ribautodelphax notabilis, a delphacid planthopper, in Iran. In this study, another planthopper, Peregrinus maidis, vector of MMV, transmitted MIMV with an estimated efficiency of 0.4–1.6% following feeding on MIMV‐infected maize plants and 64% following injection of MIMV into the hemolymph, suggesting that P. maidis gut tissues largely blocked MIMV transmission. MIMV and MMV‐HI (Hawaii) induced similar cytopathologies in cells of infected maize leaves, with virions budding through inner nuclear and endoplasmic reticulum membranes. In thin sections, virions of MIMV were significantly shorter than those of MMV‐HI. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis of virions of MIMV, MMV‐HI, MMV‐CR (Costa Rica) and MMV‐FL (Florida) yielded six proteins of which four were identified as the putative G, N, P and M proteins of plant rhabdoviruses. The N, P and M proteins of MIMV migrated faster in gels than those of the MMV isolates indicating a lower molecular weight, whereas the bands corresponding to the G proteins migrated similarly for both viruses. Polyclonal antibodies to MMV‐HI failed to react with virions of MIMV in enzyme‐linked immunosorbent assay (ELISA) and with MIMV proteins in Western blots. In contrast, these antibodies reacted strongly with MMV‐HI and MMV‐FL virions in ELISA and with MMV‐HI, MMV‐CR and MMV‐FL proteins in Western blots. Further, in ELISA, polyclonal antibodies to MMV‐MR (Mauritius) reacted weakly with MIMV virions but strongly with MMV‐HI and MMV‐FL virions. Thus, it is concluded that MIMV is a new virus of the Nucleorhabdovirus genus that may be distantly related to MMV.

Taro vein chlorosis virus: characterization and variability of a new nucleorhabdovirus

Sequencing of the monopartite RNA genome of a Fijian isolate of Taro vein chlorosis virus (TaVCV) confirmed that it is a definitive rhabdovirus with most similarity to members of the genus Nucleorhabdovirus. The TaVCV 12 020 nt negative-sense RNA genome contained six ORFs in the antigenomic sequence, equivalent to the N, P, 3, M, G and L genes that have been identified in other rhabdoviruses. The putative gene products had highest similarity to those of the nucleorhabdovirus Maize mosaic virus. A characteristic 3'-AAUUCUUUUUGGGUUGU/A-5' sequence was identified in each of the intergenic regions and the TaVCV leader and trailer sequences comprised 140 and 61 nt, respectively. Assignment of TaVCV to the genus Nucleorhabdovirus was supported by thin-section electron microscopy of TaVCV-infected taro leaves, which identified virions budding from nuclear membranes into the perinuclear space. Variability studies identified high levels of TaVCV sequence diversity. Within the L gene of 20 TaVCV isolates from Fiji, the Federated States of Micronesia, New Caledonia, Papua New Guinea, Solomon Islands and Vanuatu, maximum variability at the nucleotide level was 27.4 %. Within the N gene, maximum variability among 15 isolates at the nucleotide level was 19.3 %. The high level of TaVCV variability observed suggested that the introduction of TaVCV to the Pacific Islands was not a recent occurrence.

NE-EDRsu1 and NE-EDRbt1, Disease-resistant Sweet Corn Populations with sugary1 and brittle1 Endosperms

perate and one-half tropical sweet corn, the latter derived from tropical field corns (Brewbaker, 1978). The tropical parents were chosen for their resistance to important diseases (Brewbaker, 1979). These include the seedling, stalk, and kernel rots caused by Fusarium moniliforme Sheld., and maize mosaic virus (MMV) and maize dwarf mosaic virus (MDMV). Tropical lines also incorporate racially nonspecific tolerance of common rust, southern rust, bacterial leaf blight, northern leaf blight, brown spot, and southern leaf blight. Causal agents are Puccinia sorghi Schw., Puccinia polysora Underw., Pseudomonas avenae Mains, Exserohilum turcicum (Pass.) Leonard & Suggs, Physoderma maydis

Molecular mapping of a major gene conferring resistance to maize mosaic virus

The objective of this study was to determine the genetic basis of resistance to maize mosaic virus (MMV). Molecular markers were used to map resistance loci to MMV in a set of 91 maize (Zea mays L.) recombinant inbred lines (RILs), derived from the cross between Hi31 (a B68 conversion resistant to MMV) and Kil4 (a Thai inbred susceptible to MMV). The RILs were evaluated for MMV resistance in disease nurseries in Hawaii in the winter of 1993 and the summer of 1994. Twenty-eight highly susceptible RILs were chosen for gene mapping using the pooled-sampling approach. Initial evidence from the pooled DNA indicated that restriction fragment length polymorphism (RFLP) probes on chromosome 3 near the centromere were biased to the susceptible parent allele. Analysis of 91 RILs at 103 RFLP loci confirmed the presence of a major MMV resistance gene on chromosome 3. The resistant allele at this locus, previously named Mv1, is present in the resistant parent Hi31 and traces back to the Argentine parent used in conferring common rust resistance to B68. We conclude that resistance to MMV in B68 and Caribbean flints involves a major gene mv1 on chromosome 3 located between RFLP markers umc102 and php20508.

Registration of 13 Tropically Adapted Parental Inbred Lines of Maize Resistant to Maize Mosaic Virus

Crop ScienceVolume 37, Issue 2 cropsci1997.0011183X003700020067x p. 637-638 Registration of Parental Lines Registration of 13 Tropically Adapted Parental Inbred Lines of Maize Resistant to Maize Mosaic Virus J. L. Brewbaker, Corresponding Author J. L. Brewbaker brewbake@hawaii.edu Dep. of Horticulture, Univ. of Hawaii, 3190 Maile Way, Honolulu, HI, 96822Corresponding author (brewbake@hawaii.edu).Search for more papers by this author J. L. Brewbaker, Corresponding Author J. L. Brewbaker brewbake@hawaii.edu Dep. of Horticulture, Univ. of Hawaii, 3190 Maile Way, Honolulu, HI, 96822Corresponding author (brewbake@hawaii.edu).Search for more papers by this author First published: 01 March 1997 https://doi.org/10.2135/cropsci1997.0011183X003700020067xCitations: 5AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume37, Issue2March–April 1997Pages 637-638 RelatedInformation

Electrical Penetration Graphs from Peregrinus maidis on a susceptible maize hybrid

AbstractThe feeding behavior of Peregrinus maidis (Ashmead) (Homoptera: Delphacidae), vector of maize mosaic virus (MMV) and maize stripe virus (MStpV) in maize (Zea mays L.), has been studied by Electrical Penetration Graph (EPG). The different recordings collected have allowed the temporal distinction of three EPG signal classes. These class 1, class 2 and class 3 signals are correlated through histological sections to the feeding activities of probing, xylem ingestion and phloem ingestion, respectively. Although these signals are described by various statistical parameters, only the median allows significant differentiation between class 2 and class 3 signals, the others varying from one insect to the next. On the other hand, spectral analysis is used to describe the signal classes by associating a characteristic frequency spectrum to each. This study treats the importance of such analysis in characterizing and comparing the signals of various piercing and sucking insects.

Identification of Viruses and Mycoplasmas in Maize by Use of Light Microscopy

Maize tissues infected with maize dwarf mosaic virus (MDMV) strain A or B, maize stripe virus (MStpV), maize mosaic virus (MMV), maize rayado fino virus (MRFV), maize chlorotic dwarf virus (MCDV), maize bushy stunt mycoplasma (MBSM), or corn stunt spiroplasma (CSS) were studied by light microscopy. Intracellular inclusions in stained epidermal strips were uniquely associated with infection by MDMV-A, MDMV-B, MStpV, or MMV. For MStpV identification, paradermal sections of the leaf sheath were better sources than such sections of the leaf blade (....)

Discrimination by gel‐diffusion serology of digitaria striate, maize sterile stunt and other rhabdoviruses of Poaceae

SummaryEight rhabdoviruses from grass and cereal hosts and their antisera were used to examine virus relationships by gel‐diffusion serology. Nucleocapsid (Nc) preparations from digitaria striate virus (DSV) and maize sterile stunt virus (MSSV) both contained a major protein of c. 52 OOO daltons, and antisera prepared to these readily discriminated related planthopper‐transmitted rhabdoviruses. MSSV showed a moderately close relationship to barley yellow striate mosaic virus (BYSMV) when an antiserum prepared to whole virus was used, but the Nc antiserum showed clearer discrimination. Worthern cereal mosaic virus and DSV showed a distant relationship to BYSMV and MSSV. There was no serological relationship between any of these viruses and cereal chlorotic mottle virus, cynodon chlorotic streak virus, festuca leaf streak virus or maize mosaic virus.

Penicillinase-based enzyme-linked immunosorbent assay for the detection of plant viruses

A penicillinase (PNC)-based, enzyme-linked immunosorbent assay (ELISA) was standardized to detect maize mosaic virus (MMV) in sorghum leaf extracts, peanut mottle virus (PMV) in pea leaf extracts, and tomato spotted wilt virus (TSWV) in peanut leaf extracts. Rabbit Fc-specific antibodies were conjugated with PNC by a single step glutaraldehyde bridge. Among several indicators tested, bromothymol blue (BTB) was found suitable for measuring PNC activity under simulated conditions. Two reagents, starch-iodine complex (SIC) and a mixed pH indicator, containing bromocresol purple and BTB (2:1) used earlier for the PNC-based ELISA, were compared with BTB for utilization in the PNC-based ELISA. SIC gave a slightly higher virus titre than BTB or the mixed pH indicator, but it often gave nonspecific reactions. Sodium or potassium salts of penicillin-G at 0.5 − 1.0 mg/ml and BTB at 0.2 mg/ml were found to be suitable as substrate-indicator mixture for PNC-based ELISA. The sensitivity of the PNC system was comparable to those of the alkaline phosphatase (ALP) and horseradish peroxidase (HRP) systems in detecting MMV, PMV, and TSWV. The PNC conjugate could be used at a greater dilution than those of the ALP and HRP conjugates and the BTB substrate mixture was stable for at least 3 weeks at 4°C. Penicillin is readily available in developing countries, and at a substantially lower cost than p-nitrophenyl phosphate, the commonly used substrate for ALP in the plate ELISA. Thus the PNC-based ELISA provides a less expensive means for assaying plant viruses by ELISA.

The occurrence of maize mosaic virus on sorghum in India1

SummaryA leaf disease of sorghum (Sorghum bicolor) characterised by fine discontinuous chlorotic streaks between the veins, was observed on sorghum grown during the 1987/88 post‐rainy season in peninsular India. Early‐infected plants were stunted, had shortened internodes, and produced poorly developed panicles. The virus was transmitted by the delphacid planthopper, Peregrinus maidis. Negatively stained leaf dip preparations contained bullet‐shaped virus particles (208 ± 4.4 × 66 ± 1.0 nm) resembling those of rhabdoviruses. In ultrathin sections, the particles budded through the inner nuclear membrane and were present in the cytoplasm within membrane‐bound vesicles that were apparently contiguous with the distended outer nuclear membrane. A method for purifying the virus was developed utilising polyethylene glycol (PEG) precipitation, Celite filtration and sucrose densitygradient centrifugation. An antiserum was produced in rabbits with a titre of 1/2650 in the precipitin ring interphase test. The virus could be detected in infected sorghum leaf tissues using a direct antigen coating form of enzyme‐linked immunosorbent assay (DAC‐ELISA). In immuno‐double diffusion tests, the virus reacted positively with antisera to maize mosaic virus (MMV) from Reunion (MMV‐RN) and Hawaii (MMV‐HI), but not with antisera to barley yellow striate mosaic (BYSMV), cereal chlorotic mottle (CCMV), and cynodon chlorotic streak (CCSV) viruses. Thus, the virus isolated from sorghum is designated the MMV‐S isolate. In DAC‐ELISA tests, MMV‐S reacted positively with antisera to MMV‐R, MMV‐HI, MMV‐Florida isolate, CCSV, and CCMV, and weakly with antiserum to BYSMV. SDS‐polyacrylamide gel electrophoresis revealed four major proteins of relative mass Mr 70 000, 59 000, 32 000 and 28 000. In electro‐blot immunoassay, MMV and CCSV antisera detected the G and N proteins. These data suggest that MMV‐S should be placed in the sonchus yellow net virus subgroup of plant rhabdoviruses.