Frequency of virus in some Diplodia pinea and Gremmeniella abietina isolates originated from Turkey

Abstract

Diplodia pinea and Gremmeniella abietina are common pathogens causing shoot blight and dieback of pine all over the world. D. pinea is one of the main causal agents of shoot blight of Calabrian pines in the Mediterranean countries including Turkey. G. abietina has been recently observed on saplings and seedlings of Pinus nigra, which remain under snow cover during winter dormancy in Dedegul Mountain in the Mediterranean Region of Turkey. The presence of viruses in fungi has been known for many years. An accumulating number of cloned and sequenced viral genomes have enabled us to detect virus in increasing number of fungal species in the recent years. D. pinea and G. abietina are known to contain members of the virus families Narnaviridae, Totiviridae and Partitiviridae, which can infect single fungal isolates. Viral dispersal in fungi mainly occurs via anastomosis. Some Diplodia and G. abietina isolates have different characteristics, such as reduced virulence and growth rate, lack of pigmentation, altered colony morphology, and reduction in conidial production due to presence of viral particles. In this study, 18 D. pinea and 6 G. abietina isolates were investigated for the presence of dsRNA. Double-stranded RNA was isolated using a commercial RNA extraction kit and visualized in agarose gel electrophoresis. Isolates containing dsRNA were also investigated for their in vitro growth rate and ability to produce conidia. Three (50%) G. abietina and ten (56%) D. pinea isolates contained dsRNA that had an approximate molecular size of 1.6 kb. Key words: Scleroderris canker, calabrian pine, dsRNA.