Investigation of virus occurrence in different tissues throughout the year and sequence variability of Apple stem pitting virus

The occurrence of Apple stem pitting virus (ASPV) isolate PB 66 in three different types of tissue of four different apple varieties throughout the year was determined. Reliable virus detection in phloem tissue was observed in all four apple varieties investigated, at all sampling dates during the year. The complete nucleotide sequence of ASPV isolate PB 66 was determined and compared to ASPV isolate PA 66. The isolates show 80 % sequence identity. Comparison of the ASPV PA 66 coat protein amino acids sequence with 16 other ASPV isolates from different hosts revealed an insertion event of 18 amino acids.