Browsing by Subject "ITS-sekvensointi"

Powdery mildew fungi (Erysiphales) are obligate plant pathogens that infect almost 10 000 plant species (Magnoliophytina) worldwide. They are highly host specialised fungi that cause significant crop losses in agriculture and horticultural production. The aim of this study was to recognise and identify powdery mildew fungi occurring in the botanical garden of Helsinki University in Kumpula. Identification was based on the morphological characters and barcodes based on ITS-sequences. Altogether 94 observations were made of powdery mildews during the growth season 2015. To identify the powdery mildew fungi, the morphological characters were studied with a microscope, and 42 specimens were characterized for using powdery mildew specific primers and sequencing. All the sequences were compared with sequences available in Genbank (NCBI) using BLASTn tool. A phylogenetic tree was build from the sequences to show evolutionary distances. The sequences were also compared with an identity matrix to show nucleotide differences between the isolates. Twenty-eight species of powdery mildew fungi were identified in this study. 14 of these fungi were possible to identify based only on their morphological characters. The ITS sequences of 42 isolates were deposited to a Genbank (ENA) with accession numbers LT794916–LT795001. In most cases the primers were specific enough to multiply DNA of the powdery mildew fungi and to sequence the PCR product without cloning. The PCR products from 5 samples had to be cloned because they contained a mixture of sequences. This study shows that an area of 6 ha in the Kumpula Botanical garden contains multiple species of powdery mildew fungi. Results also show that the species found infecting the plants in the botanical garden are mostly common species that have been found earlier in Finland. A few uncommon powdery mildew species lacking the native hosts in Finland were also found.