出版社：Forestry Commission of the Hungarian Academy of Sciences
摘要：A PCR-based method was developed for the specific detection of the conifer shoot blight pathogen Sirococcus conigenus and the closely related fungus Sirococcus tsugae. Regions of diversity in the internal transcribed spacer (ITS) sequences of Sirococcus species were exploited to design primer pairs. Forward primer SirCf and reverse primer SirCr were used for identification of S. conigenus, and forward primer SirTf and reverse primer SirTr2 were used for identification of S. tsugae. Specificity was tested using multiple isolates of these two species, isolates of S. piceicola from spruce, S. clavigignenti-juglandacearum from butternut, and isolates of several other fungi obtained from pines. The PCR-based method for detection of S. conigenus was tested and results compared to those obtained using a cultural assay using shoots collected at six locations in Wisconsin and Michigan. For needles, bark, and wood of symptomatic shoots, the mean frequencies of detection of S. conigenus using the PCR-based methods were consistent (>7.5 out of 10) and always greater than for the cultural assay. For the cultural assays of symptomatic shoots, detection of Sirococcus spp. was more frequent from needles than bark or wood. Both the PCR-based method and the cultural assay detected S. conigenus in similar frequencies from asymptomatic shoots, though less frequently than from symptomatic shoots. The relative efficiency of our PCR-based method and its utility for direct testing of field-collected host material should make it particularly useful in areas of the western United States and Canada where both S. conigenus and S. tsugae have been found, and in situations in which other shoot blight pathogens also are commonly encountered
