The Fitness of Citrus Tristeza Virus Defective RNAs Is Affected by the Lengths of Their 5′- and 3′-Termini and by the Coding Capacity

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.

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New defective RNAs from citrus tristeza virus: evidence for a replicase-driven template switching mechanism in their generation.

Journal of General Virology ◽

10.1099/0022-1317-80-3-817 ◽

1999 ◽

Vol 80 (3) ◽

pp. 817-821 ◽

Cited By ~ 42

Author(s):

M A Ayll√≥n ◽

C L√≥pez ◽

J Navas-Castillo ◽

M Mawassi ◽

W O Dawson ◽

...

Keyword(s):

Citrus Tristeza Virus ◽

Template Switching ◽

Switching Mechanism ◽

Defective Rnas ◽

Tristeza Virus ◽

Citrus Tristeza

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Aphid Transmission Alters the Genomic and Defective RNA Populations of Citrus tristeza virus Isolates

Phytopathology ◽

10.1094/phyto.2000.90.2.134 ◽

2000 ◽

Vol 90 (2) ◽

pp. 134-138 ◽

Cited By ~ 39

Author(s):

M. R. Albiach-Martí ◽

J. Guerri ◽

A. Hermoso de Mendoza ◽

F. Laigret ◽

J. F. Ballester-Olmos ◽

...

Keyword(s):

Citrus Tristeza Virus ◽

Blot Hybridization ◽

Aphis Gossypii ◽

Aphid Transmission ◽

Northern Blot Hybridization ◽

Dot Blot ◽

Defective Rnas ◽

Tristeza Virus ◽

Virus Isolates ◽

Citrus Tristeza

A total of 14 Spanish isolates of Citrus tristeza virus (CTV) and 1 isolate from Japan were transmitted by Aphis gossypii, and the subisolates obtained were compared with the source isolates for symptom expression and double-stranded RNA (dsRNA) pattern. Of the 14 Spanish isolates, 9 showed altered dsRNA patterns after aphid transmission but only minor variations in the intensity of symptoms induced on Mexican lime. Northern blot hybridization with complementary DNA (cDNA) probes corresponding to both the 5′ and the 3′ termini of the CTV genomic RNA (gRNA) showed that the dsRNA bands that could be used to discriminate between the dsRNA pattern of the source and the aphid-transmitted isolates were the replicative forms of defective RNAs (D-RNAs). Conversely, the Japanese isolate and two subisolates obtained from it by aphid transmission had the same dsRNA pattern, but one of the subisolates induced milder symptoms in several hosts. Dot-blot hybridization with cDNA probes representing several regions of the gRNA showed that most of the aphid-transmitted isolates differed from the corresponding source isolate by their hybridization pattern. Our results indicate that aphid transmission often sorts the populations of gRNA variants and D-RNAs present in CTV isolates.

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