EFFECTS OF APHID TRANSMISSION ON THE STRUCTURE OF A MILD AND A SEVERE CITRUS TRISTEZA VIRUS POPULATION FROM ITALY

2015 ◽  
pp. 791-798
Author(s):  
Yahiaoui Dorsaf ◽  
Khaled Djelouah ◽  
Anna M. D'Onghia ◽  
Antonino F. Catara
Keyword(s):  
Citrus Tristeza Virus ◽  
Aphid Transmission ◽  
Virus Population ◽  
Tristeza Virus ◽  
Citrus Tristeza

scholarly journals Stem-Pitting Citrus tristeza virus Predominantly Transmitted by the Brown Citrus Aphid from Mixed Infections Containing Non-Stem-Pitting and Stem-Pitting Isolates

Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 913-920 ◽  
Author(s):  
R. H. Brlansky ◽  
Avijit Roy ◽  
V. D. Damsteegt
Keyword(s):  
Citrus Tristeza Virus ◽  
Fruit Size ◽  
Haplotype Diversity ◽  
Aphid Transmission ◽  
Single Strand Conformation Polymorphism ◽  
Mixed Infections ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Spp ◽  
Citrus Tristeza

Citrus tristeza virus (CTV) is a phloem-limited Closterovirus that produces a variety of symptoms in various Citrus spp. One of these symptoms is stem pitting (SP). SP does not occur in all Citrus spp. but when it does it may cause low tree vigor, decline, and an economic reduction in fruit size and yield. Historically, the first appearance of CTV-SP in a citrus area often occurs after the introduction of the most efficient CTV vector, the brown citrus aphid (BCA), Toxoptera citricida. Hypotheses for this association range from the introduction of these strains in new planting materials to the increased ability of BCA to transmit SP strains from existing CTV sources. It is known that CTV often exists as a complex of isolates or subisolates. Single and multiple BCA transmissions have been used to separate different genotypes or strains of CTV from mixed CTV infected plants. This study was initiated to determine what the BCA transmits when an exotic severe SP CTV isolate B12 from Brazil or B408 from Dominican Republic are mixed with a non-SP (NSP) isolate, FS627 from Florida. Biological and molecular data was generated from grafted mixtures of these isolates and their aphid-transmitted subisolates. Single-strand conformation polymorphism patterns of the 5′ terminal region of open reading frame (ORF) 1a, the overlapping region of ORF1b and ORF2, and the major coat protein gene region of NSP and SP CTV-grafted plants remained unchanged but the patterns of doubly inoculated plants varied. The haplotype diversity within SP isolates B12, B408, and mixtures of NSP and SP isolates (FS627/B12 and FS627/B408) and aphid-transmitted subisolates from doubly inoculated plants was determined by analysis of the haplotype nucleotide sequences. Aphid transmission experiments, symptoms, and molecular analyses showed that SP-CTV was more frequently transmitted with or without NSP-CTV from mixed infections.

scholarly journals Citrus Tristeza Virus Isolates of the Same Genotype Differ in Stem Pitting Severity in Grapefruit

Plant Disease ◽  
2020 ◽  
Vol 104 (9) ◽  
pp. 2362-2368
Author(s):  
Glynnis Cook ◽  
Beatrix Coetzee ◽  
Rachelle Bester ◽  
Johannes H. J. Breytenbach ◽  
Chanel Steyn ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Aphid Transmission ◽  
Common Source ◽  
Citrus Paradisi ◽  
Full Genome ◽  
Full Genome Sequencing ◽  
Reading Frame ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Tristeza

Two isolates of the T68 genotype of citrus tristeza virus (CTV) were derived from a common source, GFMS12, by single aphid transmission. These isolates, named GFMS12-8 and GFMS12-1.3, induced stem pitting with differing severity in ‘Duncan’ grapefruit (Citrus × paradisi [Macfad.]). Full-genome sequencing of these isolates showed only minor nucleotide sequence differences totaling 45 polymorphisms. Numerous nucleotide changes, in relatively close proximity, were detected in the p33 open reading frame (ORF) and the leader protease domains of ORF1a. This is the first report of full-genome characterization of CTV isolates of a single genotype, derived from the same source, but showing differences in pathogenicity. The results demonstrate the development of intragenotype heterogeneity known to occur with single-stranded RNA viruses. Identification of genetic variability between isolates showing different pathogenicity will enable interrogation of specific genome regions for potential stem pitting determinants.

scholarly journals The Haplotype Distribution of Two Genes of Citrus Tristeza Virus Is Altered after Host Change or Aphid Transmission

Virology ◽  
1999 ◽  
Vol 255 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Marı́a A. Ayllón ◽  
Luis Rubio ◽  
Andrés Moya ◽  
José Guerri ◽  
Pedro Moreno
Keyword(s):  
Citrus Tristeza Virus ◽  
Aphid Transmission ◽  
Haplotype Distribution ◽  
Tristeza Virus ◽  
Citrus Tristeza

scholarly journals Citrus Tristeza Virus: Molecular Approaches to Cross Protection

1994 ◽  
Author(s):  
William O. Dawson ◽  
Moshe Bar-Joseph ◽  
Charles L. Niblett ◽  
Ron Gafny ◽  
Richard F. Lee ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Complex Structure ◽  
Genetic System ◽  
Aphid Transmission ◽  
Open Reading Frames ◽  
Molecular Approaches ◽  
Defective Rnas ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Tristeza

Citrus tristeza virus (CTV) has the largest genomes among RNA viruses of plants. The 19,296-nt CTV genome codes for eleven open reading frames (ORFs) and can produce at least 19 protein products ranging in size from 6 to 401 kDa. The complex biology of CTV results in an unusual composition of CTV-specific RNAs in infected plants which includes multiple defective RNAs and mixed infections. The complex structure of CTV populations poses special problems for diagnosis, strain differentiation, and studies of pathogenesis. A manipulatable genetic system with the full-length cDNA copy of the CTV genome has been created which allows direct studies of various aspects of the CTV biology and pathology. This genetic system is being used to identify determinants of the decline and stem-pitting disease syndromes, as well as determinants responsible for aphid transmission.

scholarly journals Identification and Characterization of Citrus tristeza virus Isolates Breaking Resistance in Trifoliate Orange in California

2017 ◽  
Vol 107 (7) ◽  
pp. 901-908 ◽  
Author(s):  
Raymond K. Yokomi ◽  
Vijayanandraj Selvaraj ◽  
Yogita Maheshwari ◽  
Maria Saponari ◽  
Annalisa Giampetruzzi ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Aphid Transmission ◽  
Poncirus Trifoliata ◽  
Trifoliate Orange ◽  
In Planta ◽  
Sequence Identity ◽  
Group I ◽  
Genetic Profiles ◽  
Tristeza Virus ◽  
Citrus Tristeza

Most Citrus tristeza virus (CTV) isolates in California are biologically mild and symptomless in commercial cultivars on CTV tolerant rootstocks. However, to better define California CTV isolates showing divergent serological and genetic profiles, selected isolates were subjected to deep sequencing of small RNAs. Full-length sequences were assembled, annotated and trifoliate orange resistance-breaking (RB) isolates of CTV were identified. Phylogenetic relationships based on their full genomes placed three isolates in the RB clade: CA-RB-115, CA-RB-AT25, and CA-RB-AT35. The latter two isolates were obtained by aphid transmission from Murcott and Dekopon trees, respectively, containing CTV mixtures. The California RB isolates were further distinguished into two subclades. Group I included CA-RB-115 and CA-RB-AT25 with 99% nucleotide sequence identity with RB type strain NZRB-G90; and group II included CA-RB-AT35 with 99 and 96% sequence identity with Taiwan Pumelo/SP/T1 and HA18-9, respectively. The RB phenotype was confirmed by detecting CTV replication in graft-inoculated Poncirus trifoliata and transmission from P. trifoliata to sweet orange. The California RB isolates induced mild symptoms compared with severe isolates in greenhouse indexing tests. Further examination of 570 CTV accessions, acquired from approximately 1960 and maintained in planta at the Central California Tristeza Eradication Agency, revealed 16 RB positive isolates based on partial p65 sequences. Six isolates collected from 1992 to 2011 from Tulare and Kern counties were CA-RB-115-like; and 10 isolates collected from 1968 to 2010 from Riverside, Fresno, and Kern counties were CA-RB-AT35-like. The presence of the RB genotype is relevant because P. trifoliata and its hybrids are the most popular rootstocks in California.

scholarly journals Molecular Analyses of Citrus tristeza virus Subisolates Separated by Aphid Transmission

Plant Disease ◽  
2003 ◽  
Vol 87 (4) ◽  
pp. 397-401 ◽  
Author(s):  
R. H. Brlansky ◽  
V. D. Damsteegt ◽  
D. S. Howd ◽  
A. Roy
Keyword(s):  
Monoclonal Antibody ◽  
Citrus Tristeza Virus ◽  
Aphid Transmission ◽  
Variable Regions ◽  
Molecular Analyses ◽  
Field Isolates ◽  
Molecular Profiles ◽  
Tristeza Virus ◽  
Virus Isolates ◽  
Citrus Tristeza

Citrus tristeza virus (CTV) exists in field isolates as a complex of virus isolates. This complex may contain both mild and severe CTV. Using single and multiple aphid transmissions, subiso-lates of the various field isolates were separated. Some CTV isolates that tested negative with the monoclonal antibody MCA13 consisted of MCA13-positive subisolates. Using primers to specific and variable regions of the CTV genome, molecular profiles of the isolates and subisolates were generated and compared. The profiles of the subisolates sometimes were very different from the parent field isolates from which they were transmitted.

scholarly journals Segregation of Distinct Variants from Citrus tristeza virus Isolate SY568 Using Aphid Transmission

2009 ◽  
Vol 99 (10) ◽  
pp. 1168-1176 ◽  
Author(s):  
J. J. Velazquez-Monreal ◽  
D. M. Mathews ◽  
J. A. Dodds
Keyword(s):  
Citrus Tristeza Virus ◽  
Aphid Transmission ◽  
Single Infection ◽  
Mild Strain ◽  
Rnase Protection ◽  
Genetic Characteristics ◽  
Inoculum Sources ◽  
Tristeza Virus ◽  
Severe Isolate ◽  
Citrus Tristeza

A well-studied severe isolate of Citrus tristeza virus (CTV) known as SY568 has previously been shown to contain multiple variants of the virus which differ in their genetic and biological characters. Aphid transmission was used in an attempt to segregate some of these variants for further characterization. Resulting infections gave symptoms which varied from asymptomatic to more severe than the inoculum source. RNase protection assays (RPAs) were used to compare nine regions of the CTV genome and determine whether unique strains could be identified. Five aphid-transmitted subcultures, with fingerprints that were different from those of the inoculum sources in at least one genomic area, were then cloned, sequenced, and compared with known isolates. An asymptomatic strain was shown to be different in every area of the CTV genome when examined by RPA and sequencing of selected regions. Mixed-infection studies using graft transmission of the asymptomatic subculture and two of the more severe aphid-transmitted subcultures showed that the mild strain was not able to compete well when in the presence of any of the severe variants tested, and its titer was significantly reduced from that seen in single infection. The mild strain and a selected severe strain were singly graft inoculated into five different citrus hosts (sweet orange, grapefruit, sour orange, lemon, and lime), where they maintained their distinct biological and genetic characteristics.

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