Browsing by Author "Kakkuri, Päivi"

Virus–related symptoms have been observed on the birch trees grown around Helsinki in recent years. Leaf roll, vein banding, chlorosis and subsequent necrosis on leaves are typical symptoms associated with Cherry leaf roll virus (CLRV) in birch trees. Similar symptoms have been observed in birch trees of different sizes and ages growing on different kind of habitats either on urban areas or forests. The leaves collected from the birch trees were first tested with DAS–ELISA to investigate the cause of the disease symptoms occurring on birch trees of Helsinki. The test was not reliable and precise enough to detect CLRV from leaf material. Total RNA was extracted from symptomatic leaf material to detect CLRV with RT–PCR. CLRV was detected from some of the tested leaf samples of birch trees from Myllypuro, Viikki, Hietaniemi, Kannelmäki, Kaisaniemi, Roihupelto industrial area, Roihuvuori, Siilitie and Tali. The PCR–products were sequenced to confirm that the virus detected was CLRV and to analyse the CLRV–isolates. According to the analysing and phylogenetic comparison of the sequences, all of the haplotypes identified belonged to group A (birch–cherry) of CLRV. The sequence identity among haplotypes were relatively high. The sequence identities among samples and two positive controls from Germany were equal to or greater than 94,7 %. The disease symptoms found in Birch trees of Helsinki could have been associated with CLRV infection. The infection could either have affected premature decline of the birch trees or could have exposed the trees to other abiotic and biotic stresses.