Anupam Varma

Anupam Varma
Indian Agricultural Research Institute | IARI · Division of Plant Pathology

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81
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Publications (81)
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Supplementary Figure 1. Closer view of clade I, where Non reducing Aspergillus PKSs are classified and predicated to produce Aflatoxin, pigment or other non reduced compound. Supplementary Figure 2. Closer view of clade II, where Non reducing Aspergillus PKSs are classified and predicated to produce citrinin like non reduced compound and also clade...
Article
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Potato (Solanum tuberosum) is one of the important vegetable crops in the world and its production is seriously affected by apical leaf curl disease in northern India. This paper reveals the role of cucurbits in maintaining Tomato leaf curl New Delhi virus (ToLCNDV) and Potato apical leaf curl (PALCD) disease in that region. The affected plants sho...
Chapter
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Viral diseases are a major constraint in improving the productivity of crop plants. The traditional and biotechnological approaches are mainly based on avoidance of sources of infection; avoidance or control of vectors; modification of cultural practices; use of resistant varieties obtained though conventional breeding; cross protection; systemic a...
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A new disease of tobacco with characteristic mild leaf curl and yellowing symptoms was observed in 2007 in commercial plantings in Pusa, Bihar, India. A begomovirus and a betasatellite were found associated with the disease. The associated begomovirus was identified as a strain of Radish leaf curl virus (RaLCV) based on nucleotide sequence of the v...
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Apple is the major commercial horticulture crop in Himachal Pradesh and other hill states of Jammu & Kashmir, Uttarakhand and some parts of Northeastern states of India. In order to gather data on health status and incidence of virus and virus-like pathogens in apple orchards, survey was conducted in the month of June and September, 2010 in Hatkoti...
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Betasatellites are commonly associated with tomato leaf curl disease caused by begomoviruses in India. This study demonstrates the role of a betasatellite in the pathogenesis of tomato leaf curl New Delhi virus (ToLCNDV), a bipartite begomovirus affecting tomato in India. For infection, accumulation, systemic movement and disease induction by ToLCN...
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An epidemic of chilli leaf curl disease was recorded in 2004 in Jodhpur, a major chilli‐growing area in Rajasthan, India. Several isolates were efficiently transmitted by the whitefly (Bemisia tabaci), all of which induced severe leaf curl symptoms in chilli. A single whitefly was capable of transmitting the virus, and eight or more whiteflies per...
Article
Large cardamom (Amomum subulatum), an important spice crop grown in eastern sub-Himalayan mountains of India, is affected by a viral disease commonly known as 'chirke', which is characterised by light and dark green streaks on the leaf lamina. Although chirke has been known to affect large cardamom for over 50 years, its distribution in large carda...
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Leaf curl disease of tobacco (TbLCD) is endemic in India. A monopartite Begomovirus, a betasatellite and an alphasatellite were found associated with the disease in Pusa, Bihar. The DNA-A of the Begomovirus associated with TbLCD in Pusa, Bihar was found to comprise of 2707 nt with a typical Old World begomovirus-like genome organization. The full-l...
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Apple mosaic virus (ApMV), an Ilarvirus is one of the most common pathogens of apple worldwide. During field surveys in commercial plantations of Himachal Pradesh and Jammu & Kashmir, observations of bright chlorotic mosaic like symptoms on apple trees indicated probable infection by the virus, which was later detected by double antibody sandwich-e...
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The medical, agricultural and biotechnological importance of the primitive eukaryotic microorganisms, the Fungi was recognized way back in 1920. Among various groups of fungi, the Aspergillus species are studied in great detail using advances in genomics and proteomics to unravel biological and molecular mechanisms in these fungi. Aspergillus fumig...
Chapter
Whitefly-transmitted geminiviruses (WTGs) have emerged as the most destructive pathogens, particularly in the tropics and subtropics. The epidemics caused by the emerging WTGs have spread even in the regions that were free from these viruses earlier. The most seriously affected crops include cassava, cotton, grain legumes, and cucurbitaceous, malva...
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Bottle gourd (Lagenaria siceraria) an important vegetable crop in India was observed to be affected by a chlorotic curly stunt disease (CCSD) during 2003-2006 in the vegetable growing areas of Delhi and adjoining state of Haryana. The affected plants are severely stunted and bear very small chlorotic and mildly curled leaves. Incidence of the disea...
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DNA-beta satellites, referred to here as betasatellites, were found associated with tomato leaf curl disease (ToLCD) in India. The size of eight betasatellites isolated from different geographical locations in India varied from 1353 to 1424 nt; these molecules had an ORF beta C1, an adenine-rich region, and a satellite conserved region. Their nucle...
Chapter
Viruses, discovered about four decades after the publication Darwin’s treatise ‘The Origin of Species’, are important tools to address the questions related to the evolution of species. Viruses are unlikely to have existed in the pre-cellular environment, as they require the complex host cell system to replicate and are inert outside such cells. Vi...
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Genetic engineering of food crops has significantly influenced the agricultural productivity over the past two decades. It has proved a valuable tool, offering crops with higher yields, improved nutritional quality, resistance against pesticides, herbicides and tolerance against abiotic stresses. However, the safety assessment of genetically engine...
Article
In a preliminary trial 187 collections of muskmelon comprising dessert and non‐dessert types and wild Cucumis species were screened against cucumber green mottle mosaic virus (CGMMV) under field conditions. Based on the reaction to CGMMV, 64 were studied further in detail. Thirteen collections were found to be resistant in two field screenings (sum...
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Papaya ringspot potyvirus (PRSV) causes major diseases of papaya and cucurbits in the Indian subcontinent. Based on biological properties, PRSV isolates are classified as either papaya infecting (P), or non-papaya infecting (W) types. To characterise the P and W isolates from India at the molecular level, c. 1.7 Kb of the 3′-terminal regions compri...
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Agroinoculation of blackgram (Vigna mungo) by the cloned genomic components (DNA-A and DNA-B) of a non-sap transmissible isolate of mungbean yellow mosaic geminivirus (MYMV) has been demonstrated. It has been shown that MYMV has a bipartite genome. Tandem dimeric constructs of DNA-A and DNA-B were infectious when inoculated together and induced sys...
Article
Cucumber green mottle mosaic virus may spread in bottlegourd under field conditions through soil contaminated with infected plant debris followed by contact. No seed transmission was noticed in bottlegourd (Lagenaria siceraria) or vegetable marrow (Cucurbita pepo) although pollen grains and cotyledons from infected bottlegourd flowers or seeds, res...
Article
Geminiviruses associated with yellow or golden mosaic diseases of legume crops in two regions of India were compared by testing their reactivity with 27 monoclonal antibodies (MAbs) prepared to the particles of African cassava mosaic (ACMV) or Indian cassava mosaic (ICMV) viruses. The viruses fell into two main groups. Group 1 comprised isolates of...
Article
Virus-free clones of some British potato varieties, of which all commercial stocks are infected, were obtained by culturing apical meristems of sprouts on tubers. The variety Golden Wonder was freed from potato virus A, Arran Comet from potato virus X, and Epicure, Orion and Sharpe's Express from potato virus S. Of the 196 meristems cultured, forty...
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Twenty-five white clover plants were collected along a transect in each of twenty-six old permanent pastures in Britain and tested for sap-transmissible viruses. Viruses were identified by the symptoms they caused, by electron microscopy and by serological tests. Of the 683 plants tested 23 % were infected. In order of decreasing incidence the viru...
Article
Studies were carried out to search for virulent pathotypes of pea seed borne mosaic virus (PSbMV) on pea and to explore new sources of resistance in French and Indian pea collections. A virulent pathotype, PSbMV-Pi, capable of partially overcoming the recessively resistant gene sbm 1, was identified for the first time in an Indian pea line. PSbMV-P...
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Blackgram mottle virus (BMoV) was transmitted via up to 16% of seeds of different cultivars of blackgram, as determined by seedling symptom tests. The percentage of seed infection by BMoV as determined by EL1SA was even higher. Seed transmission was highest in cv. PLU-277 (15.9%), followed by cvs T-9 (11.8%), PLU-213 (7.0%) and UH-81-7 (1.3%). Seed...
Article
Of forty-seven clones of horseradish, originating from several different countries, tested, 30 contained sap-transmissible viruses; arabis mosaic virus was obtained from 53 per cent of the clones, cabbage black ring spot virus from 36 per cent and cauliflower mosaic virus from 13 per cent. Apical-meristem culture freed a clone from cabbage black ri...
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Nucleic acid extracted from purified virus was unaffected by RNase A and S1 nuclease treatment but completely degraded by DNase A treatment indicating that the viral genome is ds DNA. In nondanaturing agarose gels the viral DNA migrated as two bands at 21Kb and 6.6 Kb. The faster migrating band of 6.6 Kb may be linear from of viral DNA while slow m...
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Host range of WMV-A was restricted to the family cucurbitaceae and it could produce symptoms on Luffa sp. WMV-A was transmitted through sap and by aphid vectors; but no seed transmission was recorded. Aphis craccivora was found to be a more efficient vector than Myzus persicae in transmitting WMV- AWMV-A was found to produce amorphous cytoplasmic i...
Article
Transgenic tomato resistant to tomato leaf curl disease (ToLCD) using replicase (rep) gene sequences of Tomato leaf curl virus in antisense orientation were developed via Agrobacterium-mediated transformation. A binary vector carrying the antisense rep gene (untranslatable full length sequence, 1086bp) along with the npt II gene was used for transf...
Article
The coat protein (CP) sequences of eleven Papaya ringspot virus (PRSV) isolates originating from different locations in India were determined, analysed and compared with the sequences of other isolates of PRSV. The virus isolates from India exhibited considerable heterogeneity in the CP sequences. The CP-coding region varied in size from 840-858 nu...
Article
Large cardamom (Amomum subulatum Roxb.) is affected by the serious disease ‘foorkey’, which is of unknown etiology (1). Excessive sprouting and formation of bushy dwarf clumps at the base of mother plants that gradually die, characterize the disease. In surveys in the Sikkim-Darjeeling Hill area during 2002 and 2003, as much as 27% of plants were f...
Article
Geminiviruses encode a replication initiator protein, Rep, which binds to iterated DNA motifs functioning as essential elements for virus specific replication. Rep protein gene of three isolates of whitefly transmitted geminivirus causing leaf curl disease of tomato in India were amplified, cloned and sequenced. Nucleotide sequence and the derived...
Article
Papaya (Carica papaya L.) is an important fruit crop in Bangladesh. During surveys conducted in Dhaka and Mymensingh regions from April to June 2003, >50% of papaya plants were observed to have leaf mottling, mosaic and mild distortion, and water-soaked streaks on petioles and stem, which are typical symptoms of Papaya ring spot virus (PRSV) infect...
Article
Sponge gourd (Luffa cylindrica), an important cucurbitaceous vegetable in India, is affected by a disease (2) causing yellow spots on newly emerged leaves, mosaic, mild leaf curling and distortion, small leaves, and misshapen fruits. Nearly 100% of sponge gourd plants were symptomatic in Delhi. Geminivirus-like particles were observed with electron...
Article
In August 2002, ridge gourd (Luffa acutangula) plant samples exhibiting yellowing of leaves were collected from the experimental farm of Tamil Nadu Agricultural University, Coimbatore, India. Mechanical inoculations of ridge gourd seedlings using the above samples resulted in chlorotic spots on inoculated leaves and vein clearing followed by chloro...
Article
Geminiviruses form the second largest family of plant viruses, the Geminiviridae, represented by four genera: Mastrevirus, Curtovirus, Topocuvirus and Begomovirus. During the last two decades these viruses have emerged as devastating pathogens, particularly in the tropics and subtropics, causing huge economic losses and threatening crop production....
Article
A total of 90 genotypes of Lycopersicon species were tested forresistance to the Tomato leaf curlgeminivirus (ToLCV) by agroinoculation andthe vector whitefly (Bemisia tabaciGenn.) inoculation techniques underinsect-proof glasshouse conditions. Therate of infection in the inoculated plantswas determined by detection of the viralDNA in individual pl...
Article
Serological and coat protein sequence studies were conducted to identify an ilarvirus associated with necrosis disease on sunflower in India. In electroblot immunoassay, sunflower ilarvirus reacted strongly only with antiserum to Tobacco streak virus (TSV). The coat protein gene of sunflower ilarvirus was cloned and sequenced. The sequence analyses...
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The complete nucleotide sequence of the blackgram isolate of mungbean yellow mosaic virus, IMYMV-Bg, which infects legumes in India, was determined and compared at the amino acid level with those of other whitefly-transmitted geminiviruses. The genome organization of IMYMV-Bg was similar to that of the begomoviruses. A unique feature of the genome...
Article
A novel protein Crip-31 responsible for systemic induced resistance (SIR) against CMV, PVY and ToMV infection in susceptible host Nicotianatabacum, was purified from the leaves of Clerodendruminerme. The inducer molecule Crip-31 is proteineous, basic in nature, having hydrophobic residues and 31 kDa in molecular mass. Minimum amount of purified pre...
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Sunflower necrosis disease (SND) is becoming a potential threat to sunflower (Helianthus annuus L.) cultivation in the Indian subcontinent. The disease was first recorded in parts of Karnataka state in 1997. Since then the disease has become increasingly important in Andhra Pradesh, Karnataka, Maharashtra, and Tamil Nadu, the four major sunflower-g...
Article
Tapping panel dryness (TPD) is one of the most destructive maladies affecting rubber plantations and is becoming a matter of serious concern. Reduced latex yield leading to total drying of the tapping panel is the obvious symptom. The cause of TPD syndrome is unknown but has been mostly attributed to abiotic causes. In India, the high yielding comm...
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Two antiviral glycoproteins, active against mechanical transmission of two tobamoviruses, tobacco mosaic virus and sunnhemp rosette virus, and citrus ring spot virus (ungrouped), were purified from the dried leaves of Celosia cristata. These proteins, called CCP-25 and CCP-27, have M(r) 25 and 27 kDa, respectively. Their concentration was found to...
Article
Reciprocal cross hybridization between DNA-A and ONA-B molecules showed that MYMV genome contains certain regions common to each other. “Common region” of MYMV belongs to the 0.55 kb Kpnl-Clal fragment of DNA-A and 0.25 kb Xbal-Hind III fragment of DNA-B. Hybridization of DNA-A restriction fragments with the full length coat protein region probe to...
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We have identified banana bract mosaic potyvirus (BBMV) in banana plants growing in the Coimbatore and Tiruchchirappalli regions of southern India based on symptomatology, particle morphology, sequence homology, and nucleic acid hybridization assays. Potyvirus-like particles typical of BBMV also were detected in sap dips from banana plants growing...
Article
Blackgram mottle virus was purified from French bean (Phaseolus vulgaris) cv. Contender tissue using two different methods involving differential centrifugation. The use of Mg-bentonite during purification produced a homogeneous and pure virus preparation. The Mr of RNA and coat protein were 1400 and 39k, respectively. The RNA was infectious at a c...
Article
In vitro translation of blackgram mottle virus RNA in rabbit reticulocyte lysate resulted in synthesis of five major virus specific polypeptides with mol wt 90,000(p90), 82,000(p82), 42,000(p42), 39,000(p39) and 32,000(p32), respectively. The polypeptide p39 was identified as coat protein based on its electrophoretic mobility and immunoprecipitatio...
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Rice tungro bacilliform virus (RTBV) together with rice tungro spherical virus (RTSV) is the causal agent for the rice tungro disease. A rapid technique was developed to detect RTBV DNA in the crude extract of freshly collected leaf samples by polymerase chain reaction (PCR). This technique can detect the viral DNA in 1000-fold diluted leaf extract...
Article
Viral diseases of plants cause enormous economic losses particularly in the tropics and semitropics which provide ideal conditions for the perpetuation of viruses and their vectors. Intensive agricultural practices necessitated by the ever-increasing demands of the rapidly growing population and the introduction of new genotypes, cropping patterns...
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A ringspot disease of citrus affecting most of the citrus cultivars is widely distributed in India. I t was readily transmissible by graft inoculation and dodder (Cuscuta reflexa) but not by sap inoculations to herbaceous hosts, aphids, seed or soil. Two type of filamentous particles measuring 640 x 15 nm (C) and 690 x 9 nm (L) as well as tubules o...
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SUMMARY Red clover vein mosaic virus (RCVMV) was compared with other viruses, in particular white clover mosaic virus (WCMV) and clover yellow vein virus (CYVV). All three have filamentous particles, those of RCVMV are 645 rim. long and have a sedimentation coefficient of I6OS, those of WCMV are 46o nm. long (I~9s), and those of CYVV between 7oo nm...

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