Nucleotide analysis of pome fruit virus isolates detected in apple and pear samples from Italy and India

In the framework of a joint research project between Italy and India field surveys were done in different pear and apple growing areas of North of India and Central and Southern Italy. Samples were collected from plants belonging to common and local varieties and molecularly analyzed for the detection of the main pome fruit viruses (Apple stem pitting virus, Apple stem groving virus, Apple chlorotic leaf spot virus, Apple mosaic virus) by using harmonized diagnostic protocols.The sequence homology was evaluated and a phylogenetic tree was built, on the basis of which, the Indian isolate of ASGV showed maximum sequence identity at a nucleotide level to Italian isolates when analyzed by BLAST (http://blast.ncbi.nlm.nih.gov/Blast.cgi). Similarly, a maximum identity, ranging from 90-93%, was found for the Italian isolates of ASPV and pear and apple isolates from Poland, while a sequence homology ranging from 83 to86% was observed within the Indian isolates of ASPV. Multiple alignment of the Indian pome ACLSV-isolates indicate maximum variability in the middle portion while the first 140 nucleotides are maximally conserved and shared a percent identity at nucleotide level of 86-100% with the Italian isolates.The ApMV Indian isolates showed maximum (92-99%) sequence homology to the Korean isolate (AY125977) from apple. However, a comparison with other isolates from different host plant species revealed a clustering of Indian isolates with a Czech isolate from pear and a sequence homology of 84 to 98%. Phylogenetic analysis showed that sequence variability was independent to the geographical origin or the host for all the investigated viruses.Keywords: ACLSV, ASPV, ASGV, ApMV, sequences analysis, Italy, India

Molecular diagnosis of apple virus and viroid pathogens from India

Apple is known to be susceptible to various virus and viroid pathogens. Symptomatic apple cultivars and rootstocks were collected and analyzed by ELISA and then through RT-PCR. The study reports the presence of Apple mosaic virus (ApMV), Apple stem grooving virus (ASGV), Apple stem pitting virus (ASPV), Apple chlorotic leaf spot virus (ACLSV), the major apple viruses and Prunus necrotic ringspot virus (PNRSV), a minor apple virus, at the molecular level in India. Apple scar skin viroid (ASSVd) infection was also confirmed at the molecular level. Sporadic incidences of Tomato ringspot virus and Arabis mosaic virus infections were also detected by ELISA in nursery plant