CHARACTERIZATION OF SX/2, AN APPLE CHLOROTIC LEAF SPOT VIRUS ISOLATE SHOWING UNUSUAL COAT PROTEIN PROPERTIES

Loquat (Eriobotrya japonica) is an important crop in Spain. To date, only one viral species, apple stem pitting virus (ASPV), has been detected in Spanish loquat orchards. In this study, the presence of additional viruses infecting this crop in Spain was investigated. RT-PCR and high-throughput sequencing (HTS) of symptomatic loquat plants led to first-time detection and characterization of apple stem grooving virus (ASGV), also known as citrus tatter leaf virus (CTLV), and apple chlorotic leaf spot virus (ACLSV) from Spain with description of nearly complete genomic sequences. The frequency of ACLSV infection was the highest, with over 30% of the samples testing positive and were also detected as coinfections with ASGV and ASPV, although most of the samples infected were symptomless. Studies on all the full-length sequences available in the databases were performed in order to establish the phylogenetic relationships of the Spanish isolates of these two viral species. Moreover, apple hammerhead viroid (AHVd) was also detected to infect loquat, the first host different from apple reported for this viroid to date.

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Characterization of Apricot pseudo-chlorotic leaf spot virus, A Novel Trichovirus Isolated from Stone Fruit Trees

Phytopathology ◽

10.1094/phyto-95-0420 ◽

2005 ◽

Vol 95 (4) ◽

pp. 420-426 ◽

Cited By ~ 16

Author(s):

D. Liberti ◽

A. Marais ◽

L. Svanella-Dumas ◽

M. J. Dulucq ◽

D. Alioto ◽

...

Keyword(s):

Leaf Spot ◽

Chenopodium Quinoa ◽

Fruit Trees ◽

Open Reading Frames ◽

Spot Virus ◽

Phylogenetic Reconstructions ◽

Wide Geographical Distribution ◽

Chlorotic Leaf ◽

Reading Frames

A trichovirus closely related to Apple chlorotic leaf spot virus (ACLSV) was detected in symptomatic apricot and Japanese plum from Italy. The Sus2 isolate of this agent cross-reacted with anti-ACLSV polyclonal reagents but was not detected by broad-specificity anti- ACLSV monoclonal antibodies. It had particles with typical trichovirus morphology but, contrary to ACLSV, was unable to infect Chenopodium quinoa and C. amaranticolor. The sequence of its genome (7,494 nucleotides [nt], missing only ≈30 to 40 nt of the 5′ terminal sequence) and the partial sequence of another isolate were determined. The new virus has a genomic organization similar to that of ACLSV, with three open reading frames coding for a replication-associated protein (RNA-dependent RNA polymerase), a movement protein, and a capsid protein, respectively. However, it had only ≈65 to 67% nucleotide identity with sequenced isolates of ACLSV. The differences in serology, host range, genome sequence, and phylogenetic reconstructions for all viral proteins support the idea that this agent should be considered a new virus, for which the name Apricot pseudo-chlorotic leaf spot virus (APCLSV) is proposed. APCLSV shows substantial sequence variability and has been recovered from various Prunus sources coming from seven countries, an indication that it is likely to have a wide geographical distribution.

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Combinations of two amino acids (Ala40 and Phe75 or Ser40 and Tyr75) in the coat protein of apple chlorotic leaf spot virus are crucial for infectivity

Journal of General Virology ◽

10.1099/vir.0.82984-0 ◽

2007 ◽

Vol 88 (9) ◽

pp. 2611-2618 ◽

Cited By ~ 29

Author(s):

Hajime Yaegashi ◽

Masamichi Isogai ◽

Hiroko Tajima ◽

Teruo Sano ◽

Nobuyuki Yoshikawa

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Coat Protein ◽

Leaf Spot ◽

Amino Acid Sequences ◽

Site Directed Mutagenesis ◽

Single Amino Acid ◽

Cdna Clones ◽

Spot Virus ◽

Chlorotic Leaf

Amino acid sequences of apple chlorotic leaf spot virus (ACLSV) coat protein (CP) were compared between 12 isolates from apple, plum and cherry, and 109 cDNA clones that were amplified directly from infected apple tissues. Phylogenetic analysis based on the amino acid sequences of CP showed that the isolates and cDNA clones were separated into two major clusters in which the combinations of the five amino acids at positions 40, 59, 75, 130 and 184 (Ala40-Val59-Phe75-Ser130-Met184 or Ser40-Leu59-Tyr75-Thr130-Leu184) were highly conserved within each cluster. Site-directed mutagenesis using an infectious cDNA clone of ACLSV indicated that the combinations of two amino acids (Ala40 and Phe75 or Ser40 and Tyr75) are necessary for infectivity to Chenopodium quinoa plants by mechanical inoculation. Moreover, an agroinoculation assay indicated that the substitution of a single amino acid (Ala40 to Ser40 or Phe75 to Tyr75) resulted in extreme reduction in the accumulation of viral genomic RNA, double-stranded RNAs and viral proteins (movement protein and CP) in infiltrated tissues, suggesting that the combinations of the two amino acids at positions 40 and 75 are important for effective replication in host plant cells.

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Biological and Molecular Characterization of Apple chlorotic leaf spot virus Causing Chlorotic Leaf Spot on Pear (Pyrus pyrifolia) in Taiwan

HortScience ◽

10.21273/hortsci.45.7.1073 ◽

2010 ◽

Vol 45 (7) ◽

pp. 1073-1078 ◽

Cited By ~ 2

Author(s):

Zhong-Bin Wu ◽

Hsin-Mei Ku ◽

Yuh-Kun Chen ◽

Chung-Jan Chang ◽

Fuh-Jyh Jan

Keyword(s):

Amino Acid ◽

Leaf Spot ◽

Phylogenetic Analyses ◽

Amino Acid Sequences ◽

Pyrus Pyrifolia ◽

Spot Virus ◽

Chlorotic Spot ◽

Cp Gene ◽

Chlorotic Leaf

Pear plants (Pyrus pyrifolia var. Hengshen) showing symptoms of chlorotic spots on leaves were observed in orchards in central Taiwan in 2004. The sap of diseased leaves reacted positively to Apple chlorotic leaf spot virus (ACLSV) antiserum. A purified virus isolate (LTS1) from pear was characterized by host range, electron microscopy, phylogenetic analyses, serological property, and back-inoculation experiments to pear. Fifteen of 28 species of tested plants were susceptible to this virus after mechanical inoculation. Pathogenicity of ACLSV isolate LTS1 was verified by back-inoculating to pear seedlings. Filamentous virions of ≈12 × 750 nm were observed in the preparations of purified virus. Virus particles accumulated in the cytoplasm were observed in the ultrathin sections of LTS1-infected pear leaf tissue. Sequence analyses of the coat protein (CP) gene of LTS1 and the CP gene of LTS2, which originated from a distinct symptomatic pear sample, shared 81.4% to 92.6% nucleotide and 87.6% to 98.4% amino acid identities with those of the CP of 35 ACLSV isolates available in GenBank. ACLSV isolates were grouped into four clusters, i.e., Asia I, II, III, and Europe, and isolates LTS1 and LTS2 were classified as members of cluster Asia II and Asia I, respectively, based on phylogenetic data. Moreover, the variability of amino acid sequences of the CP gene of 37 ACLSV isolates showed geographically associated clustering in the phylogenetic tree. To our knowledge, this is the first study on the characterization of ACLSV causing the leaf chlorotic spot disease of pear in Taiwan. This study also provides the phylogenetic relationships among ACLSV populations based on amino acid sequences of CPs, which are correlated with their geographic origins.

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