scholarly journals Strain Variation and Cross Protection in Citrus Tristeza Virus on Acid Lime

1980 ◽  
Vol 8 (8) ◽  
Author(s):  
K. Balaraman ◽  
K. Ramakrishnan
Keyword(s):  
Citrus Tristeza Virus ◽  
Cross Protection ◽  
Strain Variation ◽  
Acid Lime ◽  
Tristeza Virus ◽  
Citrus Tristeza

scholarly journals Prospects of classical cross protection technique against Citrus tristeza closterovirus in Pakistan: A review

2011 ◽  
Vol 32 (No. 2) ◽  
pp. 74-83 ◽  
Author(s):  
M. Abbas ◽  
M. M Khan ◽  
S. M Mughal ◽  
I. A Khan
Keyword(s):  
Physical Properties ◽  
Citrus Tristeza Virus ◽  
Cross Protection ◽  
Citrus Tree ◽  
Citrus Groves ◽  
Drastic Effect ◽  
Citrus Tristeza Closterovirus ◽  
Tristeza Virus ◽  
Classical Cross ◽  
Citrus Tristeza

In Pakistan citrus groves in general are facing a serious problem of decline that is attributed to different causes. The major cause, however, is the prevalence of citrus virus and virus-like diseases; Citrus tristeza virus (CTV) is of utmost concern. Although CTV has been identified and characterized on the basis of serological and physical properties, no information is available on the strains of CTV in Pakistan. The identification of CTV strains will be helpful in developing strategies to control the decline of citrus trees to a great extent. Many citrus growing countries have successfully used the technique of cross protection to minimize the drastic effect of severe CTV strains. By pre-immunization of the citrus tree with mild strains, the decline can be controlled to increase the life span of the citrus tree. In this study we focus on the possibility of establishing a cross protection technique in Pakistan against the CTV strains.  

scholarly journals Breakdown of Cross-Protection of Grapefruit from Decline-Inducing Isolates of Citrus tristeza virus Following Introduction of the Brown Citrus Aphid

Plant Disease ◽  
2003 ◽  
Vol 87 (9) ◽  
pp. 1116-1118 ◽  
Author(s):  
C. A. Powell ◽  
R. R. Pelosi ◽  
P. A. Rundell ◽  
M. Cohen
Keyword(s):  
Immunosorbent Assay ◽  
Citrus Tristeza Virus ◽  
Cross Protection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Experimental Area ◽  
Toxoptera Citricida ◽  
The Cross ◽  
Tristeza Virus ◽  
Citrus Tristeza

A 21-year-old replicated field planting of 84 ‘Ruby Red’ grapefruit trees cross-protected with three mild isolates of Citrus tristeza virus (CTV) was assessed for decline-inducing and non-decline-inducing isolates of the virus 5 years after the brown citrus aphid (BrCA) (Toxoptera citricida Kirkaldy) first was established in the experimental area. Prior to the introduction of the BrCA, the cross-protecting mild isolates had significantly reduced detectable infection with decline-inducing isolates of CTV for 16 years (average infection of 13% in cross-protected trees compared with 67% in unprotected trees). After the introduction of the BrCA, infections with decline-inducing CTV (measured by enzyme-linked immunosorbent assay) were 57, 81, and 71% for trees protected with three mild isolates, respectively, compared with 95% in unprotected trees. These results suggest that the introduction of BrCA accelerated the breakdown of cross-protection against decline-inducing isolates of CTV in grapefruit.

scholarly journals Walking Together: Cross-Protection, Genome Conservation, and the Replication Machinery of Citrus tristeza virus

Viruses ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1353
Author(s):  
Svetlana Y. Folimonova ◽  
Diann Achor ◽  
Moshe Bar-Joseph
Keyword(s):  
Citrus Tristeza Virus ◽  
Fluorescent Protein ◽  
Field Tests ◽  
Fruit Trees ◽  
Plant Viruses ◽  
Cross Protection ◽  
Virus Variant ◽  
Tristeza Virus ◽  
Direct Confirmation ◽  
Citrus Tristeza

“Cross-protection”, a nearly 100 years-old virological term, is suggested to be changed to “close protection”. Evidence for the need of such change has accumulated over the past six decades from the laboratory experiments and field tests conducted by plant pathologists and plant virologists working with different plant viruses, and, in particular, from research on Citrus tristeza virus (CTV). A direct confirmation of such close protection came with the finding that “pre-immunization” of citrus plants with the variants of the T36 strain of CTV but not with variants of other virus strains was providing protection against a fluorescent protein-tagged T36-based recombinant virus variant. Under natural conditions close protection is functional and is closely associated both with the conservation of the CTV genome sequence and prevention of superinfection by closely similar isolates. It is suggested that the mechanism is primarily directed to prevent the danger of virus population collapse that could be expected to result through quasispecies divergence of large RNA genomes of the CTV variants continuously replicating within long-living and highly voluminous fruit trees. This review article provides an overview of the CTV cross-protection research, along with a discussion of the phenomenon in the context of the CTV biology and genetics.

scholarly journals Characterization of Citrus tristeza virus Single-Variant Sources in Grapefruit in Greenhouse and Field Trials

Plant Disease ◽  
2016 ◽  
Vol 100 (11) ◽  
pp. 2251-2256 ◽  
Author(s):  
Glynnis Cook ◽  
Stephanus P. van Vuuren ◽  
Johannes H. J. Breytenbach ◽  
Chanel Steyn ◽  
Johan T. Burger ◽  
...  
Keyword(s):  
Citrus Tristeza Virus ◽  
Phenotypic Expression ◽  
Field Trials ◽  
Cross Protection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Limiting Factor ◽  
Phenotypic Effect ◽  
Tristeza Virus ◽  
Stem Pitting ◽  
Citrus Tristeza

Citrus tristeza virus (CTV) is endemic to southern Africa and the stem pitting syndrome that it causes was a limiting factor in grapefruit production prior to the introduction of cross-protection in the Citrus Improvement Scheme. This disease mitigation strategy, using various field-derived CTV sources, has significantly extended the productive lifespan of grapefruit orchards in South Africa. CTV commonly occurs as a population of various strains, masking the phenotypic effect of individual strains. Likewise, current South African CTV cross-protection sources are strain mixtures, obscuring an understanding of which strains are influencing cross-protection. The severity of various CTV strains has mostly been assessed on sensitive indicator hosts, but their effect on commercial varieties has seldom been investigated. Single-variant CTV isolates were used to investigate the phenotypic expression of CTV strains in commercial grapefruit varieties as well as CTV indicator hosts. They were biologically characterized for their ability to cause stem pitting and their rate of translocation and titer in the different hosts, monitored by enzyme-linked immunosorbent assay. Complete genome sequences for three CTV strain variants were generated. Isolates of CTV strains VT, T68, RB, and HA16-5 did not induce severe stem pitting in four grapefruit hosts in a glasshouse trial. Viral titers of the strains differed in the grapefruit hosts, but the RB isolate reached a higher titer in the grapefruit hosts compared with the VT, T68, and HA16-5 isolates. Additionally, horticultural assessment of two grapefruit varieties inoculated with the RB isolate in two field trials demonstrated that mild stem pitting did not negatively influence the horticultural performance of the grapefruit trees over an eight-year assessment period. ‘Star Ruby’ trees containing the CTV source GFMS35 showed less stem pitting than trees inoculated with the RB isolate, but had smaller canopy volumes and lower yields than trees containing the RB isolate. This suggests that the influence of CTV sources on tree performance is not limited to the effect of stem pitting.

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