Indian Peanut Research Articles

Anatomy of sporosori of Polymyxa graminis, the vector of Indian peanut clump virus, in roots of Sorghum bicolor

(1997). Anatomy of sporosori of Polymyxa graminis, the vector of Indian peanut clump virus, in roots of Sorghum bicolor. Canadian Journal of Plant Pathology: Vol. 19, No. 3, pp. 281-288.

The nucleotide sequence of RNA-1 of Indian peanut clump furovius.

The nucleotide sequence of RNA-1 of an isolate of the H serotype of Indian peanut clump virus (IPCV-H) was shown to comprise 5,841 nucleotides. The RNA contains three open reading frames (ORF) which are between nucleotides 133 and 3,522, nucleotides 3,526 and 5,103 (assuming expression by suppression of the ORF 1 termination codon) and nucleotides 5,168 and 5,539. The encoded polypeptides have M(r), of 129,687 (p130), 60,188 (p60) and 14,281 (p14). ORF 2 is thought to be expressed by suppression of the termination codon of ORF 1 to produce a M(r) 189,975 product (p190). p130 contains sequences characteristic of proteins with methyl transferase and NTP-binding properties and p190 contains these and sequences characteristic of RNA-dependent RNA polymerases. The nucleotide sequence of IPCV RNA-1 is similar to that of peanut clump virus (PCV) and corresponding encoded polypeptides are 88% (p130), 95% p60 and 75% (p14) identical. The sequences of the translation products are also similar to those of soil-borne wheat mosaic virus and barley stripe mosaic virus. Oligonucleotide primers, designed on the basis of the sequences of RNA-1 of IPCV and PCV, were effective in reverse transcription-PCR amplification of these RNAs and that of IPCV isolates of the serologically distinct L and T serotypes.

Sensitive Broad-Spectrum Detection of Indian Peanut Clump Virus by Nonradioactive Nucleic Acid Probes

Cloned cDNA fragments representing different regions of the genome of the H serotype of Indian peanut clump furovirus (IPCV) were used as hybridization probes. Dot-blot assays using digoxigenin-labeled probes readily detected IPCV in extracts from infected plants with a sensitivity approaching that of using 32 P-labeled probes. The specificity of the probes depended on the part of the IPCV genome represented in the cDNA. Two probes representing the coat protein gene and adjacent gene in RNA-2 readily detected infection by H serotype IPCV, but reacted poorly with samples of plants infected with other serotypes. A probe corresponding to sequence near the 5'-end of RNA-1 reacted with samples of all IPCV serotypes, but not with those of peanut clump virus (PCV) from West Africa. A probe corresponding to the 3'-terminal 742 nucleotides of RNA-1 readily detected RNA of any IPCV serotype and of PCV. Assays using this probe, labeled with a nonradioactive reporter-digoxigenin, could detect IPCV in samples of seed tissue, as well as in tissue of several weed species and crop species such as wheat. The probe did not react with samples from plants infected by other furoviruses.

A Disease of Wheat Caused by Indian Peanut Clump Virus (IPCV).

A Disease of Wheat Caused by Indian Peanut Clump Virus (IPCV).

Severe stunting of wheat caused by the Indian peanut clump virus (IPCV), possibly vectored by Polymyxa sp

Severe stunting of wheat caused by the Indian peanut clump virus (IPCV), possibly vectored by Polymyxa sp

The coat protein of Indian peanut clump virus: relationships with other furoviruses and with barley stripe mosaic virus.

The 5'-most open reading frame of the c.4kb RNA-2 of Indian peanut clump furovirus (IPCV) encodes a protein of 208 amino acids. This protein is thought to be the coat protein of IPCV because its amino acid composition and M(r) closely resemble those reported for IPCV coat protein and because its amino acid sequence is 61% identical to that of the coat protein of peanut clump virus (PCV) from West Africa. The extent of the sequence identity between IPCV and PCV coat proteins confirms previous conclusions that the viruses are distinct rather than strains of one virus. The sequences of the coat proteins of IPCV and PCV were between 18% and 26% identical to those of other furoviruses and those of unrelated tobamoviruses and tobraviruses. In contrast, the coat protein sequences were 37% (IPCV) and 36% (PCV) identical to that of the coat protein of barley stripe mosaic hordeivirus (BSMV). This similarity between the coat proteins of viruses from different groups (= genera) is unusual but is consistent with previous reports of sequence relatedness in various genes between certain furoviruses and BSMV.

Monoclonal antibodies specific for potato mop‐top virus, and some properties of the coat protein

SummaryA method was devised which gave consistent yields (1–2 mg/kg leaves) of potato mop‐top furovirus (PMTV) particles. Monoclonal antibodies (MAbs) were produced and some properties of 10 of them were studied. Four MAbs readily detected PMTV isolates from six countries in Northern Europe and Japan when the isolates were trapped with polyclonal antibody; and diagnostic tests based solely on MAbs (SCR 68 to coat plates and biotin‐ or enzyme‐labelled SCR 69 to detect trapped virus) were devised. The pattern of reactions of the MAbs in ELISA and immunoblots suggested that they react with at least five different epitopes.PMTV coat protein preparations were analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS‐PAGE) and immunoblotting. Three bands of 23.9 kd, 21.5 kd and 20.5 kd were visible in silver‐stained gels and all three reacted with PMTV specific MAbs. The relative amounts of the three bands varied between different virus preparations, but the 21.5 kd band was usually the most abundant. The three bands were probably not produced by anomalous behaviour in SDS‐PAGE. Moreover PMTV protein was readily degraded by trypsin treatment giving a band of 20.5 kd. Therefore the results suggest that PMTV coat protein sub‐units are sensitive to degradation by plant proteases. At least two degraded forms were found when purified preparations were analysed by SDS‐PAGE, and the undegraded protein was estimated to be 23.9 kd.The PMTV MAbs did not react in immunoblots with SDS‐treated coat protein preparations of beet necrotic yellow vein furovirus or Indian peanut clump furovirus.

Studies on transmission of Indian peanut clump virus disease by Polymyxa graminis*

SummaryThe plasmodiophoromycete fungus, Polymyxa graminis was observed in the roots of Sorghum bicolor, S. sudanense, Pennisetum glaucum, Triticum aestivum, Cyperus rotundus, Eleucine coracana, Zea mays, Tridax procumbens and Arachis hypogaea collected from Indian peanut clump virus (IPCV)‐infested fields. Examination of roots of IPCV‐infected S. bicolor, S. sudanense, P. glaucum and T. aestivum grown in previously air dried field soil also showed the presence of cystosori of P. graminis. IPCV‐infested soil stored at room temperature for 3 years transmitted the virus to A. hypogaea, T. aestivum and S. bicolor. Roots extracted from IPCV‐infected P. glaucum and S. bicolor containing cystosori, and dried root fragments incorporated into sterile soil, transmitted the virus to A. hypogaea and T. aestivum. The root extracts contained primary zoospores of the fungus, presumably arising from cystosori. Utilising root fragments of S. sudanense containing cystosori as inoculum P. graminis was shown to infect both monocotyledonous and dicotyledonous plants. Profuse cystosorus production in rootlets only occurred in monocotyledonous plants. In dicotyledonous plants, in general, only few rootlets showed cystosori. Indian isolates of P. graminis appear to differ from isolates from temperate soils in that they can infect dicotyledonous plants and have a much wider host range.

Indian Peanut Clump Virus Isolates: Host Range, Symptomatology, Serological Relationships, and Some Physical Properties

The symptomatology of Indian peanut clump virus (IPCV) isolates collected from five different geographical locations, Bapatla (B), Chinnaganjam (C), Hyderabad (H), Ludhiana (L), and Talod (T), differed. B-IPCV and C-IPCV were indistinguishable by host range but could be distinguished from the other isolates by symptoms on Canavalia ensiformis, Nicotiana clevelandii × glutinosa, Phaseolus vulgaris, and Vigna unguiculata. B-IPCV, C-IPCV, and T-IPCV were related serologically, but could be distinguished from H-IPCV and L-IPCV isolates in serological tests. The five isolates could not be distinguished on the basis of particle size. Each isolate contained two RNA species of 1.90 × 106 and 1.65 × 106 Mr estimated under nondenaturing conditions and a single polypeptide of 24 × 103 Mr. Significance of these findings for the diagnosis of IPCV and for screening of peanut genotypes for resistance is discussed.

Use of Direct Antigen Coating and Protein A Coating ELISA Procedures for Detection of Three Peanut Viruses

Direct antigen coating (DAC) and protein A coating (PAC) forms of indirect enzyme-linked immunosorbent assay (ELISA) were standardized and compared with the double-antibody sandwich (DAS) form of direct ELISA for their usefulness in the detection of three peanut viruses: peanut mottle virus (PMV), tomato spotted wilt virus (TSWV), and Indian peanut clump virus (IPCV). PMV was detectable in peanut seeds and pea tissue at a 1:10,000 dilution in buffer with the DAC and at a 1:1,000 dilution with the PAC procedures. With the DAS procedure, PMV was detectable in pea tissue at a 1:1,000 dilution and in peanut seed at a 1:100 dilution. TSWV was detectable in peanut leaves at a 1:1,000 dilution with the DAC method and at 1:100 with the PAC and DAS methods. IPCV was detectable in peanut leaves at a 1:100 dilution by the DAC, PAC, and DAS methods. Sensitivity of DAC and PAC methods was, therefore, comparable to that of the DAS procedure under the short incubation period (1–2 hr at 35 C) conditions employed in the experiments.

Genome Properties and Relationships of Indian Peanut Clump Virus

SUMMARY RNA extracted from the rod-shaped particles of Indian peanut clump virus (IPCV), strain L, consisted predominantly of two single-stranded species with mol. wt., estimated by gel electrophoresis of glyoxal-denatured samples, of 1.83 × 106 (RNA-1) and 1.35 × 106 (RNA-2). Both RNA-1 and RNA-2 were needed for lesion production in leaves of Phaseolus vulgaris cv. Topcrop. Strong nucleotide sequence homologies were detected among three strains of IPCV by nucleic acid hybridization tests. Less strong homologies were found between these Indian isolates and peanut clump virus (PCV) from West Africa. These results, together with similarities in symptomatology, particle size and mode of natural spread, indicate that the Indian isolates are best considered to be strains of PCV. However, no relationship was detected by immunosorbent electron microscopy either between the three Indian strains or between these and the West African strain. Although PCV has properties typical of the proposed furovirus group, no serological relationship was detected between any of the four strains and beet necrotic yellow vein, potato mop-top or soil-borne wheat mosaic viruses.

Translation Products of RNA from Indian Peanut Clump Virus

SUMMARY When RNA from particles of Indian peanut clump virus (IPCV) was translated using messenger-dependent reticulocyte lysate the largest product had a mol. wt. of about 195000 and the other main products had mol. wt. of 143000 and 24500. The 24500 mol. wt. polypeptide co-migrated with IPCV coat protein and was the only product that reacted with antiserum to IPCV particles. Translation of separated RNA species showed that the 195000 mol. wt. and 143000 mol. wt., as well as some smaller less abundant products, arose from translation of RNA-1 (mol. wt. 1.9 × 106) whereas RNA-2 (mol. wt. 1.6 × 106) was translated to give only the 24500 mol. wt. product Translation of RNA of mol. wt. 0.5 × 106 to 0.9 × 106 gave a 50000 mol. wt. product that was present and sometimes prominent in translation products of unfractionated RNA. A product of about 20000 mol. wt. was made by translation of RNA of about 0.2 × 106 mol. wt. IPCV resembles the viruses with bipartite genomes whose larger RNA species is translated into large polypeptides and whose coat protein gene is on the smaller RNA species. The other translation products may be those of subgenomic messenger, or of satellite, RNA species.

The occurrence of Indian peanut clump, a soil‐borne virus disease of groundnuts (Arachis hypogaea) in India*

SUMMARYA disease characterised by severely stunted plants with small dark green leaves was found in groundnut (Arachis hypogaea) in sandy soils in Punjab State, India. The disease occurred in patches in the field and reappeared in the same positions in succeeding groundnut crops. Plants infected early did not produce mature pods. Seeds sown in soil collected from infected fields produced plants with typical disease symptoms. Phaseolus vulgaris cv. Local and Chenopodium quinoa were found to be good diagnostic hosts. The disease was shown to be caused by a rod‐shaped virus c. 24 nm in diameter with predominant particle lengths of c. 249 and 184 nm when stained in uranyl acetate. The virus, named Indian peanut clump virus (IPCV), resembled peanut clump virus (PCV) reported from W. Africa in symptomatology on groundnuts, particle morphology and soil‐borne nature. However, it is not serologically related to two W. African PCV isolates tested, or to tobacco rattle (PRN and CAM strains) or pea early browning virus (Dutch isolate) in microprecipitin, enzyme linked immunosorbent assay and immunosorbent electron microscopy tests.