A comparative survey, by expressed sequence tag analysis, of genes expressed in peach leaves infected withPlum pox virus(PPV) and free from PPV

Plum pox virus (PPV), genus Potyvirus, is a serious threat to the fruit and ornamental horticulture industry in Canada. Genomic resources of its natural hosts, Prunus spp., currently available to researchers studying PPV are very poor. Systematic sequencing of expressed sequence tags (ESTs) can be used as a discovery base for genes associated with PPV infection, replication, and symptom development. Here we describe the construction of two directional, size-selected cDNA libraries derived from PPV-infected and PPV-free peach leaves, and the generation of 3839 ESTs. Based on their partial sequences and putative functions, the ESTs are classified into 611 clusters and 1153 singletons. About 65.36% of the genes (2509 ESTs) show homology to genes from other organisms, and 34.64% of cDNAs (1330 ESTs) have no matches in the GenBank database. Comparison analyses suggest that genes involved in defence, cellular transport, development, protein synthesis, proteins with binding function in the PPV-infected peach lea...