Browsing by Subject "phytoplasma"

Phytoplasmas are plant pathogenic phloem colonizing bacteria-like organisms. They can cause severe growth disorders in plants and thus weaken the productivity of crop plants or even kill them. Phytoplasmas have not caused any epidemics on crop plants in Finland and thus they have been little studied. The aim of this study was to find out if plants that have phytoplasma-like symptoms are actually infected by phytoplasmas. Plants with growth disorders were collected and their DNA was extracted. Phytoplasmal DNA was multiplied from the samples using PCR with phytoplasma-specific primers P1 and P7. The products were sequenced and compared with sequences available from databases. Phylogenetic trees were constructed to show the kinship between the phytoplasmas. In this thesis X-disease phytoplasmas were found from dandelion (Taraxacum spp. Weber), scentless mayweed (Tripleurospermun inodorum Schultz Bip.), creeping thistle (Cirsium arvense L.), alsike clover (Trifolium hybridum L.) and blueberry (Vaccinium myrtillus L.). Aster yellows phytoplasma was found from one red clover (Trifolium pratense L.). Data on phytoplasmas has not been published in other Nordic countries. In Lithuania phytoplasmas have been detected in several plant species such as raspberry (Rubus idaeus L.), sour cherry (Prunus cerasus L.), apple (Malus sp. Mill.), barley (Hordeum vulgare L.), oat (Avena sativa L.) and several other grasses that also grow in Finland. The climate change can increase the amount of vector insects in Finland, which will most likely help phytoplasmas spread more efficiently and cause diseases also on crop plants. The import of plants from other countries may enable the spread of new vector and phytoplasma species in Finland.