Raja Ram - Academia.edu (original) (raw)

Papers by Raja Ram

Research paper thumbnail of Evaluations of fortified fungicide solutions in managing corm rot disease of gladiolus caused by Fusarium oxysporum

Crop Protection, 2004

Corm rot caused by the fungal pathogen Fusarium oxysporum f. sp. gladioli is a dreaded disease in... more Corm rot caused by the fungal pathogen Fusarium oxysporum f. sp. gladioli is a dreaded disease in gladiolus causing huge financial loss to the growers. Experiments were conducted to find a suitable fungicide for corm dip treatment to control this disease. On the basis of ...

Research paper thumbnail of In vitro production of Prunus necrotic ringspot virus-free begonias through chemo- and thermotherapy

Scientia Horticulturae, 2005

Prunus necrotic ringspot virus (PNRSV)-free Begonia spp. plants were raised from petioles of viru... more Prunus necrotic ringspot virus (PNRSV)-free Begonia spp. plants were raised from petioles of virus-infected plants using in vitro techniques. The petioles were grown on MS medium supplemented with 0.2 mg/l NAA and 0.2 mg/l BAP (pH 5.8). For rooting, half-strength MS medium without any plant growth regulators was used. On rooting medium, shoots were subjected to chemotherapy (virazole, 2-thiouracil or 6-azauracil) and thermotherapy (38 • C for 16 h light period and 22 • C for 8 h dark period) separately or in combination. Regenerated plants (treated with chemo-and thermotherapy) were indexed for PNRSV by DAS-ELISA and RT-PCR. An amplified product of 785 bp was obtained by RT-PCR in PNRSV-infected plants. Virazole at a concentration of 20 mg/l was found to be more effective (30 and 20% of PNRSV-free plants as indexed by ELISA and RT-PCR, respectively) in comparison to the other chemicals. Thermotherapy for 25 days gave 35 and 25% PNRSV-free plants as indexed by DAS-ELISA and RT-PCR, respectively. A combination of both treatments gave a good number of PNRSV-free plants (67.5 and 57.5% as indexed by DAS-ELISA and RT-PCR, respectively). At higher concentrations all three chemicals were found to be toxic. Thermotherapy for more than 25 days caused browning of leaves and shoots died.

Research paper thumbnail of Screening for viruses infecting chrysanthemum cultivars in India

Scientia Horticulturae, 2007

... cultivars from India. The methods have also been standardized to eradicate these viruses from... more ... cultivars from India. The methods have also been standardized to eradicate these viruses from Chrysanthemum cv. Regol Time using tissue culture technique (Verma et al., 2004 and Ram et al., 2005). A number of chrysanthemum ...

Research paper thumbnail of Cucumber Mosaic Virus on Asiatic Hybrid Lilies in India

Plant Disease, 1999

Asiatic hybrid lilies are popular cut flowers with a range of bright colors. Of the several virus... more Asiatic hybrid lilies are popular cut flowers with a range of bright colors. Of the several viruses reported from lily (2,3), cucumber mosaic virus (CMV) reduces flower quality and yield (1). Classical symptoms of CMV were observed in recently introduced plants of Asiatic hybrid lilies in ...

Research paper thumbnail of First report of Cymbidium mosaic virus (CymMV) in orchids from India

Research paper thumbnail of Production of Cucumber mosaic virus-free chrysanthemums by meristem tip culture

Crop Protection, 2004

Chrysanthemum cv. Regol Time was found infected with a viral disease showing characteristic chlor... more Chrysanthemum cv. Regol Time was found infected with a viral disease showing characteristic chlorotic spots on leaves and stunting of plants. The virus was identified as Cucumber mosaic cucumovirus (CMV) on the basis of mechanical inoculation on Chenopodium amaranticolor and Cucumis sativus, DAS-ELISA and RT-PCR. CMV was eliminated from chrysanthemum plants using meristem tip culture. MS medium amended with BAP

Research paper thumbnail of Identification, detection and frequency of lily viruses in Northern India

Scientia Horticulturae, 2005

In a survey of lily growing fields in various parts of Himachal Pradesh, India, three viruses, Cu... more In a survey of lily growing fields in various parts of Himachal Pradesh, India, three viruses, Cucumber mosaic (CMV), Lily symptomless (LSV) and Lily mottle virus (LMoV) lily strain, were found quite prevalent in Asiatic (12 cultivars) and Oriental hybrids (4 cultivars) of lily, Lilium longiflorum and L. tigrinum. Apart from these viruses, Strawberry latent ringspot virus (SLRSV) was also found to infect Oriental hybrid lily. The disease incidence on the basis of symptoms observed ranged between minimum (40.7%) in cv. Alaska and maximum (83.7%) in cv. America, both Asiatic hybrid lily types. These viruses were indexed by testing outer and inner scales of bulbs and the leaves at early and flowering stages using ELISA and reverse transcription polymerase chain reaction (RT-PCR). Mechanical and insect transmission, purification, electron microscopy and sequencing of the PCR fragments were carried out for these viruses. Cloning and sequence analysis confirmed the viruses as CMV-subgroup II, LSVand LMoV. There were 96-98% nucleotide and 93-97% amino acid homology with CMV subgroup II sequences, 97-99% nucleotide and 91-92% amino acid homology with LSV sequences and 92-99% nucleotide and 85-98% amino acid homology with LMoV sequences. #

Research paper thumbnail of Characterization of an Indian isolate of Carnation mottle virus infecting carnations

Carnation (Dianthus caryophyllus L.) is an important cutflower crop. It is susceptible to infecti... more Carnation (Dianthus caryophyllus L.) is an important cutflower crop. It is susceptible to infection by several viruses, which cause significant losses to all types of carnations. Carnation mottle virus (CarMV) is one of the most important viruses among them. Ninety-three carnation cultivars collected from different parts of India were screened serologically with DAS-ELISA using polyclonal IgG. About 90% of the cultivars tested were found positive for CarMV, indicating the widespread nature of CarMV in India. CarMV was separated from other carnation viruses by host-range studies and maintained on Saponaria vaccaria and Catharanthus roseus. The virus was purified from infected S. vaccaria leaves and characterized by SDS-PAGE. Morphological studies of CarMV were conducted by electron microscopy and immune electron microscopy. The electron micrograph showed isometric particles of about 30 nm in diameter, typical of CarMV. Complete coat protein (CP) and movement protein (p7 and p9) genes of CarMV were amplified by RT-PCR with virus-specific primers. IC-RT-PCR was also used for sensitive detection of CarMV. Sequence alignment of the CP gene of Indian isolate of CarMV with other established isolates further confirmed the virus as CarMV. Though the amino acid sequence of CP was highly homologous, there are distinct differences. The Indian isolate is different from the already available classification of CarMV isolates. Isolates from the world belong to either the PK (P 164 K 331 ) or AN (A 164 N 331 ) group, while the Indian isolate belongs to a new group PN (P 164 N 331 ). The p7 protein showed 85-98% amino acid similarity with the available protein sequences. The p9 protein showed 91-96% amino acid similarity with the available protein sequences of CarMV.

Research paper thumbnail of First report of Dasheen mosaic virus infecting four ornamental aroids in India

Research paper thumbnail of An overview of diagnostics for viruses infecting gladiolus

Crop Protection, 2003

In order to improve the crop productivity, quality of germplasm and minimise infection in differe... more In order to improve the crop productivity, quality of germplasm and minimise infection in different cultivars of gladiolus, its proper diagnosis and control is essential. In addition, diagnosis also helps in exporting planting material to countries wherein strict quarantine conditions have been imposed. During the last two decades much advance has been made in diagnostics for the detection of viral diseases, but incidence of viral infection is increasing. In plants, emphasis has always been given to the diagnosis of viral infection in different parts of plants, particularly in the propagating material as it indirectly helps in the control of the infection. As well as Immuno-diagnostics, molecular biology has also provided techniques like the use of DNA/RNA probes, the polymerase chain reaction, etc. to detect the viruses. These techniques have shown great potential as far as specificity and sensitivity are concerned.

Research paper thumbnail of Status of bean yellow mosaic virus on Gladiolus

Crop Protection, 2002

The status of bean yellow mosaic virus (BYMV) in 32 cultivars of Gladiolus was investigated by ex... more The status of bean yellow mosaic virus (BYMV) in 32 cultivars of Gladiolus was investigated by examining the plants visually as well as by using the techniques like ELISA. Incidence of the disease was found to range from 0% to 100% on visual basis, whereas ELISA revealed almost 100% infection in plants, which were showing the symptoms. Almost 30% of the symptomless Gladiolus plants were also the carrier of the virus. Plants found positive for BYMV by ELISA were confirmed to carry the virus with immuno electron microscopy, cytopathological studies and by RT-PCR analysis employing primers specific to BYMV. The present investigation revealed the wide spread occurrence of BYMV in various Gladiolus cultivars whether with or without symptoms and the study suggested that symptomless plants must be examined for the presence of the virus before using them for healthy propagule production. r

Research paper thumbnail of Recombination and phylogeographical analysis of Lily symptomless virus

Virus Genes, 2008

The complete genomic nucleotide sequence of an Indian isolate of Lily symptomless virus (LSV) was... more The complete genomic nucleotide sequence of an Indian isolate of Lily symptomless virus (LSV) was determined by sequencing 11 overlapping cDNA fragments of different sizes. The genome consisted of 8,394 nucleotides, excluding the poly (A) tail and contained six open reading frames (ORFs) coding protein for ORF1 220 kDa [1,948 amino acid (aa)], ORF2 25 kDa (228 aa), ORF3 12 kDa (106 aa), ORF4 7 kDa (64 aa), ORF5 32 kDa (291 aa) and ORF6 16 kDa (140 aa) from 5′ to 3′ end. Sequence was analyzed with other previously characterized full genomes of LSV. Phylogenetic analysis on the basis of RNA-dependent RNA polymerase (RdRp), Triple gene block proteins (TGB’s), Coat protein (CP), and ORF6 (16 kDa protein) amino acid sequence revealed that Indian isolate is closely related to The Netherlands Isolate (AJ564638). The overall genome of the present LSV isolate shares 97–98% nucleotide sequence homology with the previously characterized isolates. The phylogenetic analysis, sequence alignment studies, and recombination detection program (RDP3) analysis provided evidence for the occurrence of recombination between the present isolate (AM422452) as major parent and The Netherlands Isolate (AJ564638) and Chinese isolate (AM263208) as minor parents in two different independent recombination events. Based on the recombination analysis, it is suggested that the 3′ end of the present isolate is involved in recombination with Chinese isolate (AM263208) and gave rise to the Korean isolate. To the best of our knowledge, this is the first report of complete nucleotide sequence from India and also the first evidence of homologous recombination in LSV.

Research paper thumbnail of Detection of Prunus necrotic ringspot virus in begonia by RT-PCR

Research paper thumbnail of Ornithogalum: a new host of Cucumber mosaic virus (CMV) from India

Research paper thumbnail of Indexing and production of virus-free chrysanthemums

Biologia Plantarum, 2005

Chrysanthemum morifolium cv. Regol Time plants were found to be infected with Chrysanthemum B car... more Chrysanthemum morifolium cv. Regol Time plants were found to be infected with Chrysanthemum B carlavirus (CVB). They were made CVB-free by using meristem tip culture, chemotherapy and thermotherapy. The plants were indexed by biological assay, double antibody sandwitch enzyme linked immunosorbent assay (DAS-ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR). The maximum number of virus-free plants (26.7 %, as indexed by RT-PCR) was obtained with 2-thiouracil at 0.04 g dm−3 concentration. Only 12 % plants were found to be virus-free, after being kept at 38 °C for 30 d. For indexing CVB in chrysanthemums, RT-PCR was found to be the most reliable method.

Research paper thumbnail of Detection, identification and incidence of Chrysanthemum B carlavirus in chrysanthemum in India

Crop Protection, 2003

During a survey of chrysanthemum cvs. grown in Himachal Pradesh. (India) a variety of symptoms we... more During a survey of chrysanthemum cvs. grown in Himachal Pradesh. (India) a variety of symptoms were seen. The disease incidence ranged between 40.62% and 94.66%. Out of 36cvs. surveyed 7 were found to be negative for CBV in DAS-ELISA. The virus has a very narrow host ...

Research paper thumbnail of Evaluations of fortified fungicide solutions in managing corm rot disease of gladiolus caused by Fusarium oxysporum

Crop Protection, 2004

Corm rot caused by the fungal pathogen Fusarium oxysporum f. sp. gladioli is a dreaded disease in... more Corm rot caused by the fungal pathogen Fusarium oxysporum f. sp. gladioli is a dreaded disease in gladiolus causing huge financial loss to the growers. Experiments were conducted to find a suitable fungicide for corm dip treatment to control this disease. On the basis of ...

Research paper thumbnail of In vitro production of Prunus necrotic ringspot virus-free begonias through chemo- and thermotherapy

Scientia Horticulturae, 2005

Prunus necrotic ringspot virus (PNRSV)-free Begonia spp. plants were raised from petioles of viru... more Prunus necrotic ringspot virus (PNRSV)-free Begonia spp. plants were raised from petioles of virus-infected plants using in vitro techniques. The petioles were grown on MS medium supplemented with 0.2 mg/l NAA and 0.2 mg/l BAP (pH 5.8). For rooting, half-strength MS medium without any plant growth regulators was used. On rooting medium, shoots were subjected to chemotherapy (virazole, 2-thiouracil or 6-azauracil) and thermotherapy (38 • C for 16 h light period and 22 • C for 8 h dark period) separately or in combination. Regenerated plants (treated with chemo-and thermotherapy) were indexed for PNRSV by DAS-ELISA and RT-PCR. An amplified product of 785 bp was obtained by RT-PCR in PNRSV-infected plants. Virazole at a concentration of 20 mg/l was found to be more effective (30 and 20% of PNRSV-free plants as indexed by ELISA and RT-PCR, respectively) in comparison to the other chemicals. Thermotherapy for 25 days gave 35 and 25% PNRSV-free plants as indexed by DAS-ELISA and RT-PCR, respectively. A combination of both treatments gave a good number of PNRSV-free plants (67.5 and 57.5% as indexed by DAS-ELISA and RT-PCR, respectively). At higher concentrations all three chemicals were found to be toxic. Thermotherapy for more than 25 days caused browning of leaves and shoots died.

Research paper thumbnail of Screening for viruses infecting chrysanthemum cultivars in India

Scientia Horticulturae, 2007

... cultivars from India. The methods have also been standardized to eradicate these viruses from... more ... cultivars from India. The methods have also been standardized to eradicate these viruses from Chrysanthemum cv. Regol Time using tissue culture technique (Verma et al., 2004 and Ram et al., 2005). A number of chrysanthemum ...

Research paper thumbnail of Cucumber Mosaic Virus on Asiatic Hybrid Lilies in India

Plant Disease, 1999

Asiatic hybrid lilies are popular cut flowers with a range of bright colors. Of the several virus... more Asiatic hybrid lilies are popular cut flowers with a range of bright colors. Of the several viruses reported from lily (2,3), cucumber mosaic virus (CMV) reduces flower quality and yield (1). Classical symptoms of CMV were observed in recently introduced plants of Asiatic hybrid lilies in ...

Research paper thumbnail of First report of Cymbidium mosaic virus (CymMV) in orchids from India

Research paper thumbnail of Production of Cucumber mosaic virus-free chrysanthemums by meristem tip culture

Crop Protection, 2004

Chrysanthemum cv. Regol Time was found infected with a viral disease showing characteristic chlor... more Chrysanthemum cv. Regol Time was found infected with a viral disease showing characteristic chlorotic spots on leaves and stunting of plants. The virus was identified as Cucumber mosaic cucumovirus (CMV) on the basis of mechanical inoculation on Chenopodium amaranticolor and Cucumis sativus, DAS-ELISA and RT-PCR. CMV was eliminated from chrysanthemum plants using meristem tip culture. MS medium amended with BAP

Research paper thumbnail of Identification, detection and frequency of lily viruses in Northern India

Scientia Horticulturae, 2005

In a survey of lily growing fields in various parts of Himachal Pradesh, India, three viruses, Cu... more In a survey of lily growing fields in various parts of Himachal Pradesh, India, three viruses, Cucumber mosaic (CMV), Lily symptomless (LSV) and Lily mottle virus (LMoV) lily strain, were found quite prevalent in Asiatic (12 cultivars) and Oriental hybrids (4 cultivars) of lily, Lilium longiflorum and L. tigrinum. Apart from these viruses, Strawberry latent ringspot virus (SLRSV) was also found to infect Oriental hybrid lily. The disease incidence on the basis of symptoms observed ranged between minimum (40.7%) in cv. Alaska and maximum (83.7%) in cv. America, both Asiatic hybrid lily types. These viruses were indexed by testing outer and inner scales of bulbs and the leaves at early and flowering stages using ELISA and reverse transcription polymerase chain reaction (RT-PCR). Mechanical and insect transmission, purification, electron microscopy and sequencing of the PCR fragments were carried out for these viruses. Cloning and sequence analysis confirmed the viruses as CMV-subgroup II, LSVand LMoV. There were 96-98% nucleotide and 93-97% amino acid homology with CMV subgroup II sequences, 97-99% nucleotide and 91-92% amino acid homology with LSV sequences and 92-99% nucleotide and 85-98% amino acid homology with LMoV sequences. #

Research paper thumbnail of Characterization of an Indian isolate of Carnation mottle virus infecting carnations

Carnation (Dianthus caryophyllus L.) is an important cutflower crop. It is susceptible to infecti... more Carnation (Dianthus caryophyllus L.) is an important cutflower crop. It is susceptible to infection by several viruses, which cause significant losses to all types of carnations. Carnation mottle virus (CarMV) is one of the most important viruses among them. Ninety-three carnation cultivars collected from different parts of India were screened serologically with DAS-ELISA using polyclonal IgG. About 90% of the cultivars tested were found positive for CarMV, indicating the widespread nature of CarMV in India. CarMV was separated from other carnation viruses by host-range studies and maintained on Saponaria vaccaria and Catharanthus roseus. The virus was purified from infected S. vaccaria leaves and characterized by SDS-PAGE. Morphological studies of CarMV were conducted by electron microscopy and immune electron microscopy. The electron micrograph showed isometric particles of about 30 nm in diameter, typical of CarMV. Complete coat protein (CP) and movement protein (p7 and p9) genes of CarMV were amplified by RT-PCR with virus-specific primers. IC-RT-PCR was also used for sensitive detection of CarMV. Sequence alignment of the CP gene of Indian isolate of CarMV with other established isolates further confirmed the virus as CarMV. Though the amino acid sequence of CP was highly homologous, there are distinct differences. The Indian isolate is different from the already available classification of CarMV isolates. Isolates from the world belong to either the PK (P 164 K 331 ) or AN (A 164 N 331 ) group, while the Indian isolate belongs to a new group PN (P 164 N 331 ). The p7 protein showed 85-98% amino acid similarity with the available protein sequences. The p9 protein showed 91-96% amino acid similarity with the available protein sequences of CarMV.

Research paper thumbnail of First report of Dasheen mosaic virus infecting four ornamental aroids in India

Research paper thumbnail of An overview of diagnostics for viruses infecting gladiolus

Crop Protection, 2003

In order to improve the crop productivity, quality of germplasm and minimise infection in differe... more In order to improve the crop productivity, quality of germplasm and minimise infection in different cultivars of gladiolus, its proper diagnosis and control is essential. In addition, diagnosis also helps in exporting planting material to countries wherein strict quarantine conditions have been imposed. During the last two decades much advance has been made in diagnostics for the detection of viral diseases, but incidence of viral infection is increasing. In plants, emphasis has always been given to the diagnosis of viral infection in different parts of plants, particularly in the propagating material as it indirectly helps in the control of the infection. As well as Immuno-diagnostics, molecular biology has also provided techniques like the use of DNA/RNA probes, the polymerase chain reaction, etc. to detect the viruses. These techniques have shown great potential as far as specificity and sensitivity are concerned.

Research paper thumbnail of Status of bean yellow mosaic virus on Gladiolus

Crop Protection, 2002

The status of bean yellow mosaic virus (BYMV) in 32 cultivars of Gladiolus was investigated by ex... more The status of bean yellow mosaic virus (BYMV) in 32 cultivars of Gladiolus was investigated by examining the plants visually as well as by using the techniques like ELISA. Incidence of the disease was found to range from 0% to 100% on visual basis, whereas ELISA revealed almost 100% infection in plants, which were showing the symptoms. Almost 30% of the symptomless Gladiolus plants were also the carrier of the virus. Plants found positive for BYMV by ELISA were confirmed to carry the virus with immuno electron microscopy, cytopathological studies and by RT-PCR analysis employing primers specific to BYMV. The present investigation revealed the wide spread occurrence of BYMV in various Gladiolus cultivars whether with or without symptoms and the study suggested that symptomless plants must be examined for the presence of the virus before using them for healthy propagule production. r

Research paper thumbnail of Recombination and phylogeographical analysis of Lily symptomless virus

Virus Genes, 2008

The complete genomic nucleotide sequence of an Indian isolate of Lily symptomless virus (LSV) was... more The complete genomic nucleotide sequence of an Indian isolate of Lily symptomless virus (LSV) was determined by sequencing 11 overlapping cDNA fragments of different sizes. The genome consisted of 8,394 nucleotides, excluding the poly (A) tail and contained six open reading frames (ORFs) coding protein for ORF1 220 kDa [1,948 amino acid (aa)], ORF2 25 kDa (228 aa), ORF3 12 kDa (106 aa), ORF4 7 kDa (64 aa), ORF5 32 kDa (291 aa) and ORF6 16 kDa (140 aa) from 5′ to 3′ end. Sequence was analyzed with other previously characterized full genomes of LSV. Phylogenetic analysis on the basis of RNA-dependent RNA polymerase (RdRp), Triple gene block proteins (TGB’s), Coat protein (CP), and ORF6 (16 kDa protein) amino acid sequence revealed that Indian isolate is closely related to The Netherlands Isolate (AJ564638). The overall genome of the present LSV isolate shares 97–98% nucleotide sequence homology with the previously characterized isolates. The phylogenetic analysis, sequence alignment studies, and recombination detection program (RDP3) analysis provided evidence for the occurrence of recombination between the present isolate (AM422452) as major parent and The Netherlands Isolate (AJ564638) and Chinese isolate (AM263208) as minor parents in two different independent recombination events. Based on the recombination analysis, it is suggested that the 3′ end of the present isolate is involved in recombination with Chinese isolate (AM263208) and gave rise to the Korean isolate. To the best of our knowledge, this is the first report of complete nucleotide sequence from India and also the first evidence of homologous recombination in LSV.

Research paper thumbnail of Detection of Prunus necrotic ringspot virus in begonia by RT-PCR

Research paper thumbnail of Ornithogalum: a new host of Cucumber mosaic virus (CMV) from India

Research paper thumbnail of Indexing and production of virus-free chrysanthemums

Biologia Plantarum, 2005

Chrysanthemum morifolium cv. Regol Time plants were found to be infected with Chrysanthemum B car... more Chrysanthemum morifolium cv. Regol Time plants were found to be infected with Chrysanthemum B carlavirus (CVB). They were made CVB-free by using meristem tip culture, chemotherapy and thermotherapy. The plants were indexed by biological assay, double antibody sandwitch enzyme linked immunosorbent assay (DAS-ELISA) and reverse transcriptase polymerase chain reaction (RT-PCR). The maximum number of virus-free plants (26.7 %, as indexed by RT-PCR) was obtained with 2-thiouracil at 0.04 g dm−3 concentration. Only 12 % plants were found to be virus-free, after being kept at 38 °C for 30 d. For indexing CVB in chrysanthemums, RT-PCR was found to be the most reliable method.

Research paper thumbnail of Detection, identification and incidence of Chrysanthemum B carlavirus in chrysanthemum in India

Crop Protection, 2003

During a survey of chrysanthemum cvs. grown in Himachal Pradesh. (India) a variety of symptoms we... more During a survey of chrysanthemum cvs. grown in Himachal Pradesh. (India) a variety of symptoms were seen. The disease incidence ranged between 40.62% and 94.66%. Out of 36cvs. surveyed 7 were found to be negative for CBV in DAS-ELISA. The virus has a very narrow host ...