Location matters: from changing a presumption about the Citrus tristeza virus tissue tropism to understanding the stem pitting disease

2021 ◽  
Author(s):  
Yong‐Duo Sun ◽  
Svetlana Y. Folimonova
1995 ◽  
Author(s):  
Richard Lee ◽  
Moshe Bar-Joseph ◽  
K.S. Derrick ◽  
Aliza Vardi ◽  
Roland Brlansky ◽  
...  

Citrus tristeza virus (CTV) is the most important virus disease of citrus in the world. CTV causes death of trees on sour orange rootstock and/or stem pitting of scions regardless of rootstock which results in trees of low vigor, reduced yield with reduction in size and quality of fruit. The purpose of this project was to produce monoclonal antibodies (MABs) to CTV coat protein (CP), develop single domain antibodies (dAbs) or Fab fragments which neutralize the infection by binding to the virus, and to produce transformed plants which express the dAbs. The objectives of this research have been met and putative transgenic tobacco and citrus plants have been developed. These putative transgenic plants are presently undergoing evaluation to determine the level of dAbs expression and to determine their resistance to CTV. Additionally, the CTV genome has been sequenced and the CP gene of several biologically characterized CTV strains molecular characterized. This has indicated a correlation between CP sequence homology and biological activity, and the finding of DI RNAs associated with some CTV strains. Several MABs have been produced which enable broad spectrum identification of CTV strains while other MABs enable differentiation between mild and severe strains. The use of selected MAbs and determination of the CP gene sequence has enabled predictions of biological activities of unknown CTV isolates. The epitopes of two MABs, one reacting selectively with severe CTV strains and the other reacting with all strains, have been characterized at the molecular level.


2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Gözde Erkiş-Güngör ◽  
Bayram Çevik

The presence of Citrus tristeza virus (CTV) in Turkey has been known since the 1960s and the virus was detected in all citrus growing regions of the country. Even though serological and biological characteristics of CTV have been studied since the 1980s, molecular characteristics of CTV isolates have not been studied to date in Turkey. In this study, molecular characteristics of 15 CTV isolates collected from different citrus growing regions of Turkey were determined by amplification, cloning, and sequencing of their major coat protein (CP) genes. The sequence analysis showed that the CP genes were highly conserved among Turkish isolates. However, isolates from different regions showed more genetic variation than isolates from the same region. Turkish isolates were clustered into three phylogenetic groups showing no association with geographical origins, host, or symptoms induced in indicator plants. Phylogenetic analysis of Turkish isolates with isolates from different citrus growing regions of the world including well-characterized type isolates of previously established strain specific groups revealed that some Turkish isolates were closely related to severe quick decline or stem pitting isolates. The results demonstrated that although CTV isolates from Turkey are considered biologically mild, majority of them contain severe components potentially causing quick decline or stem pitting.


Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 913-920 ◽  
Author(s):  
R. H. Brlansky ◽  
Avijit Roy ◽  
V. D. Damsteegt

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.


Plant Disease ◽  
2020 ◽  
Vol 104 (9) ◽  
pp. 2362-2368
Author(s):  
Glynnis Cook ◽  
Beatrix Coetzee ◽  
Rachelle Bester ◽  
Johannes H. J. Breytenbach ◽  
Chanel Steyn ◽  
...  

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.


2008 ◽  
pp. 51-56
Author(s):  
R. Sdoodee ◽  
P. Tothaum ◽  
J. Worapattamasri ◽  
P. Jantaradsamee ◽  
S. Patnantawech ◽  
...  

EDIS ◽  
2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Amit Levy ◽  
Ozgur Batuman ◽  
Peggy Sieburth ◽  
Ajia Paolillo ◽  
Kuang-Ren Chung ◽  
...  

This document is one in a series designed to provide important information on the causal agent, symptoms, and transmission of exotic citrus diseases. This information can be used as an educational tool to raise awareness about these diseases and for scouting and identification efforts. Disseminating information about the diseases to the citrus industry may prevent their introduction and spread in Florida. This document will focus on the exotic viral disease caused by isolates of citrus tristeza virus–stem pitting (CTV-SP). Original version: Chung, Kuang-Ren, and Ronald Brlansky. 2006. “Citrus Diseases Exotic to Florida: Citrus Tristeza Virus– Stem Pitting (CTV-SP)”. EDIS 2006 (7). https://doi.org/10.32473/edis-pp149-2006.


2009 ◽  
Vol 127 (1) ◽  
pp. 1-6
Author(s):  
Latanya C. Fisher ◽  
Paula F. Tennant ◽  
Wayne A. McLaughlin

2017 ◽  
Vol 29 (2) ◽  
pp. 273
Author(s):  
Sagheer Atta ◽  
Maroof Siddiq ◽  
Sidra Ashiq ◽  
Abdul Hannan

Citrus is one of the most widely grown fruit crop in the world. Citrus tristeza virus (CTV) is one of the most economically important viral pathogen of citrus and causes different disease syndromes. The use of infected bud wood and aphids are the main cause of spread of CTV. The virus is genetically diverse and causes various symptoms like slow and quick decline, stunting, stem pitting, vein clearing and seedling yellows. Strategies have been developed to reduce the economic losses caused by CTV. Quarantine measures, bud wood certification, mild strain cross protection and eradication programs are some of the strategies that can prevent the spread of this disease. New approaches are provided by advancement in genetic engineering and molecular biology. Transgenic plants have been developed to provide resistance against the disease. 


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