Molecular evidence of Apple Stem Grooving Virus infecting Pear in India

Pear leaf samples exhibiting severe virus-like symptoms (such as distortion, chlorosis, chlorotic spots, marginal chlorosis and necrotic spots) were collected from the pome and stone fruit germplasm fields of CSIR-IHBT campus and Horticulture department of CSKHPKV Palampur (Himachal Pradesh). The leaf samples collected from 46 plants belonging to three different cultivars (Kashmiri pear, babhugosha and patharnakh) were subject to virus indexing by DAS ELISA, dot blot hybridization and validated by RT-PCR. Total three samples found positive were used for the characterization of complete CP gene of the virus. The three isolates characterized from the pear (HPPR-2, HPPR-3 and HPPR-46) shared 93.2–96.6% sequence identity (at amino acid level) among themselves and in the phylogenetic tree these three isolates grouped in separate clusters. The sequence identity (at amino acid level) with rest of the pear isolates characterized from other countries like South Korea, Japan, China and Taiwan was found to range from 95.7 to 97.4% in case of HPPR-2, 94-95.3% for HPPR-3 and 94.9–97.4% for HPPR-46.