Evidence of Recombinant Citrus tristeza virus Isolate Occurring in Acid Lime cv. Pant Lemon Orchard in Uttarakhand Terai Region of Northern Himalaya in India (original) (raw)
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Virusdisease, 2018
Citrus tristeza virus (CTV, genus ) is one of the most serious pathogens responsible for huge loss of citrus trees worldwide. Four Indian CTV isolates, Kat1 (/Central India), D1 (/North India), B5 (/South India) and G28 (/Northeast India) collected from different regions of India were characterized based on sequencing of 3' half genome (~ 8.4 kb) comprising 10 open reading frames (ORFs2-11) and 3' UTR and the sequences were submitted to NCBI database as Acc. No KJ914662, HQ912022, HQ912023 and KJ914661, respectively. The present and previously reported Indian isolates Kpg3 and B165 were analyzed and compared with other Asian and international CTV isolates. The Indian CTV isolates had 92-99% nt identities among them. The phylogenetic analysis generated overall ten genogroups/lineages. Of them, all the Asian isolates fell into seven genogroups, whereas the Indian isolates into four. Indian isolates Kat1, D1 and Kpg3 grouped together, termed "Kpg3Gr", along with Flori...
Tarafdar, A., Godara, S., Diwedi S. and Biswas, K. K. , 2013
"Citrus tristeza virus (CTV) is an important plant virus under genus Closterovirus causing huge losses of citrus trees in India. Assam and Meghalaya states in the Northeast and Tirupati region in Andhra Pradesh in the South of India produce many commercial citrus fruits. A survey was made in citrus growing areas in these two regions to study the incidence of CTV disease and several infected citrus samples were collected for detection and molecular characterization of the virus. Twenty two CTV isolates; 11 from Tirupati, seven from Assam and four from Meghalaya were characterized and genetic diversity among them were determined based on sequencing of a 404 nt fragment of L Pro domain of 5’ORF1a (5’ORF1a) and complete CP gene (672 nt) of CTV genome. Pair-wise sequence analyses showed a range of 83-98% and 88-99% nt identity among the Assam-Meghalaya; and 88- 98% and 87- 98% nt identity among the Tirupati isolates, for 5’ORF1a and CP gene, respectively. Phylogenetic analyses determined that Assam- Meghalaya isolates fell into four to five and the Tirupati isolates into three to five genogroups based on 5’ORF1a and CP gene. The recombination-detecting program RDP3 identified recombination events in the isolates MB3, MB6 and MU6 of Meghalaya, and AR1 and TP6 of Tirupati and determined them as putative recombinant isolates originating by exchange of genetic material from diverse CTV isolates."
Distribution, genetic diversity and recombination analysis of Citrus tristeza virus of India
Biswas, K. K., Tarafdar, A., Diwedi, S. and Lee, R. F. , 2012
"Citrus tristeza virus (CTV) isolates representing all the citrus-growing geographical zones of India were analyzed for nucleotide sequence of the 50ORF1a fragments of the partial LProI domain and for the coat protein (CP) gene. The nucleotide sequences were compared with previously reported Indian and CTV genotypes from GenBank. The Indian isolates had 80–99 % sequence identity for the 50ORF1a and 89–99 % identity for the CP genes. In phylogenetic tree analysis, all the Indian and previously reported isolates segregated into eight clades or groups for the 50ORF1a region. Indian CTV isolates were clustered in all the clades, four of which, D13, K5, BAN-1, and B165, consisted of only Indian isolates. Phylogenetic tree analysis of the CP genes resulted in seven clades. Indian CTV isolates clustered in six of them, and clades I and VI consisted of only Indian isolates. In the phylogenetic tree the Indian CTV isolates clustered in different groups regardless their geographical origin. Diversities in CTV isolates within individual citrus farms were highlighted. Because incongruent phylogenetic relationships were observed for both of the genomic regions, 50ORF1a and CP gene, recombination analysis was performed using program RDP3. This analysis detected potential recombination events among the CTV isolates which involved exchange of sequences between divergent CTV variants. The SplitsTree analysis showed evidence of phylogenetic conflicts in evolutionary relationships among CTV isolates."
Archives of virology, 2004
Citrus tristeza virus (CTV) is usually present in field trees as a mixture or complex of isolates. Different biological types of CTV exist in India and this affects disease incidence and yield in the various citrus growing areas. Genotypic profiles were determined for 21 Indian CTV isolates. Of the 21 isolates, 15 contained only the VT genotype. The other isolates contained mixtures of either T30 or T3 with VT or T30, T3 and VT genotypes. One exception was isolate BAN-1, which contained a mixture of T36, T30 and T3 genotypes. Sequence diversity of Indian CTV isolates was determined by characterization in the k17 region of ORF 1a and the overlapping region of RdRp, gene p33, and sequence differences were utilized to identify group-specific genome features. A phylogenetic analysis of these regions divided the isolates into five distinct groups. There was a general trend for severe isolates to cluster into one of four groups and mild isolates into the fifth group. All the sequences fro...
Molecular characterization of Citrus tristeza virus strains in Peninsular Malaysia
African Journal of Microbiology Research, 2011
From six different districts of Punjab, Pakistan, 85 isolates of Citrus tristeza virus (CTV) were collected and characterized based on coat protein gene (CPG) analysis. All isolates were collected from field trees showing various CTV symptoms such as decline in most citrus varieties, inverse pitting on some sour orange rootstocks below bud union, mild-to-moderate stem-pitting on the trunk of some sweet orange. The CTV CP gene of all isolates was amplified by reverse transcriptase polymerase chain reaction (RT-PCR) using CP gene-specific primers yielding 672 bp. The maximum disease incidence was found in sweet orange followed by mandarin and grapefruit. These isolates were then subjected to CPG/Hinf I restriction fragment length polymorphism (RFLP) analysis. Mixed infection of CTV isolates was found very common in the field tress in Pakistan. The most dominant CPG/Hinf I RFLP groups III, I and VI are the basic causal epidemic in Pakistan. Moreover, based on symptoms in the field trees, CPG/Hinf I RFLP groups III, I and VI are considered to be the obvious causes of decline and stem-pitting in Pakistan.
African Journal of Biotechnology
From six different districts of Punjab, Pakistan, 85 isolates of Citrus tristeza virus (CTV) were collected and characterized based on coat protein gene (CPG) analysis. All isolates were collected from field trees showing various CTV symptoms such as decline in most citrus varieties, inverse pitting on some sour orange rootstocks below bud union, mild-to-moderate stem-pitting on the trunk of some sweet orange. The CTV CP gene of all isolates was amplified by reverse transcriptase polymerase chain reaction (RT-PCR) using CP gene-specific primers yielding 672 bp. The maximum disease incidence was found in sweet orange followed by mandarin and grapefruit. These isolates were then subjected to CPG/Hinf I restriction fragment length polymorphism (RFLP) analysis. Mixed infection of CTV isolates was found very common in the field tress in Pakistan. The most dominant CPG/Hinf I RFLP groups III, I and VI are the basic causal epidemic in Pakistan. Moreover, based on symptoms in the field trees, CPG/Hinf I RFLP groups III, I and VI are considered to be the obvious causes of decline and stem-pitting in Pakistan.
Molecular characterization of citrus tristeza virus (CTV) isolates in Calabria region (South Italy)
2009
From six different districts of Punjab, Pakistan, 85 isolates of Citrus tristeza virus (CTV) were collected and characterized based on coat protein gene (CPG) analysis. All isolates were collected from field trees showing various CTV symptoms such as decline in most citrus varieties, inverse pitting on some sour orange rootstocks below bud union, mild-to-moderate stem-pitting on the trunk of some sweet orange. The CTV CP gene of all isolates was amplified by reverse transcriptase polymerase chain reaction (RT-PCR) using CP gene-specific primers yielding 672 bp. The maximum disease incidence was found in sweet orange followed by mandarin and grapefruit. These isolates were then subjected to CPG/Hinf I restriction fragment length polymorphism (RFLP) analysis. Mixed infection of CTV isolates was found very common in the field tress in Pakistan. The most dominant CPG/Hinf I RFLP groups III, I and VI are the basic causal epidemic in Pakistan. Moreover, based on symptoms in the field trees, CPG/Hinf I RFLP groups III, I and VI are considered to be the obvious causes of decline and stem-pitting in Pakistan.
Archives of Virology, 2018
Citrus tristeza virus, the most important viral disease of citrus, is reported in Assam and other NE states of India to infect Khasi mandarin (Citrus reticulata), the most economically important citrus crop of the region. For effective management, an attempt was made to identify a potential mild isolate against virus. Leaf samples were collected from Khasi Mandarin plants expressing differential symptoms from three different locations viz., Tinsukia, Golaghat and Mariani of Upper Brahmaputra Valley Zone of Assam. These were then grouped into three categories based on ELISA OD 405 values. Biological indexing with CTV positive samples from these three serological categories on Mexican lime (Citrus aurantifolia) seedlings resulted in symptom expression within three months post grafting. Visible symptoms of CTV infection were observed in some of the graft successful indicator plants whereas, in Khasi mandarin selection ‗CRS 4', no visible symptom development took place within this period. Based on the results, the plants were grouped into two groups-symptom producing and nonsymptom producing, and were confirmed through Bi-directional RT-PCR with mild and severe strain primers. PCR products for ‗CRS 4' were sequenced. Consensus sequences showed a single nucleotide difference at position 371 for mild isolates (CRS 4), thereby confirming the identity.
K. K. Biswas, A. Tarafdar, S. K. Sharma, J. K. Singh, S. Dwivedi, K. Biswas and B. K. Jayakumar, 2014
"Citrus tristeza virus (CTV), a member of genus Closterovirus, is an important pathogen which has destroyed more than one million citrus trees in India till date. Survey was conducted in commercial Citrus sp. covering all the citrus growing geographical zones of India. For detection of CTV and estimation of disease incidence, direct antigen coatedenzyme linked immuno-sorbent assay (DAC-ELISA), reverse transcription- polymerase chain reaction and nucleotide sequence analyses were employed. The overall CTV incidence of 26.3% in Vidarbha region, 47.1-56.0% in Northeast (Assam, Meghalaya, Sikkim and the Darjeeling hills), 36-50% in South (Andhra Pradesh and Karnataka) and 16-60% in North-Northwest (Uttarakhand, Delhi and Punjab) were reported. CTV titre in infected tree samples of different locations was measured by ELISA. The high titre was observed in Kagzilime (C. aurantifolia) and sweet orange (C. sinensis) but low in mandarin (C. reticulata). Nucleotide sequence of 5’ORF1a fragment of CTV genome of nine representative CTV isolates, Kat-8, RA-3, B-6, Dh-1, An-9, TP-4, Pant-3, MU-2 and As-2 from all the citrus growing regions surveyed were analysed. The present Indian isolates showed 78-98% identities among them, and placed in different clusters in phylogenetic analysis. This is for the first time an overall incidence of CTV and its spatial distribution in citrus growing geographical zones of India were reported. Findings presented in this study will help in understanding epidemiology and formulating molecular based management strategy."