Identification and characterization of Apple stem grooving virus causing leaf distortion on pear (Pyrus pyrifolia) in Taiwan

Abstract

A putative virus-induced disease of pear (Pyrus pyrifolia var. Hengshen) showing symptoms of reduced size of foliage and leaf distortion was observed in orchards in central Taiwan in 2004. The sap of symptomatic leaf samples reacted positively to an antiserum against Apple stem grooving virus (ASGV). Two virus cultures, designated as TS1 and TS2, were isolated from symptomatic pears. Flexuous filamentous virions of similar to 12 x 600 nm were observed in symptomatic pear leaves and purified virus preparations. Results of back inoculation of pear seedlings with TS1 revealed that ASGV was the causal agent of the disease. Sequence analyses of the cloned coat protein (CP) genes of TS1 and TS2 shared 88-92.4% nucleotide and 90.7-97.1% amino acid identities with those of other ASGV isolates available in GenBank. The polyclonal antibody generated against ASGV TS1 has been routinely used for the detection of the ASGV-infection in the imported pear scions for quarantine purpose via enzyme-linked immunosorbent assays (ELISAs). One of 1,199 samples of pear scions imported from Japan during 2005-2007 was identified as ASGV-positive and the virus was designated as AGJP-22. The CP gene amplified from this AGJP-22 shared 97.9-98.3% amino acid identities to those of the domestic isolates and they were closely related phylogenetically. To date, these data present for the first time conclusive evidence revealing that ASGV is indeed the causal agent of the pear disease displaying symptoms of reduced size of foliage and leaf distortion in Taiwan

The functions of triple gene block proteins and coat protein of apple stem pitting virus in viral cell‐to‐cell movement

“…The ASPV proteins have the typical features of potex-like proteins (Jelkmann, 1994). Previous studies have revealed the remarkable genetic variability among ASPV isolates (Liu et al, 2012;Wu et al, 2010;Yeon et al, 2014).…”

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

“…Recently, a pear plant showing symptoms of small leaves and leaf distortion in Taiwan has been identified to be caused by a pear isolate of ASGV (Wu et al, 2010). Another pear disease, consisting of chlorotic spots on the leaves of the pear cultivar Hengshen, had been observed in the orchards in central Taiwan.…”

Development and validation of protocols for virus, viroid and phytoplasma detection to be used for the certification of pome fruit propagation material

“…Their main means of transmission is through infected propagation plant material. Single infections with ASPV and ASGV are symptomless in apple but can cause diverse symptoms in pear like vein yellowing or red mottling, and pear black necrotic leaf spot, respectively (Pleše et al, 1975;Shim et al, 2004;Wu et al, 2010;Massart et al, 2011;). In addition, mixed infections of the three viruses are very common and can cause complex disease symptoms in both apple and pear trees, resulting in significant reduction in quality and yield (Posnette 1989;Petrzik and Lenz, 2002;Boulila 2010;Hadidi et al, 2011;Massart et al, 2011;.…”