TreeBASE Search-Analyses for study 10162

@ARTICLE{TreeBASE2Ref18653, author = {Y. J. Choi and Marco Thines and Fabian Runge and S. B. Hong and Sabine Telle and H. D. Shin}, title = {Evidence for high degrees of specialisation, evolutionary diversity, and morphological distinctiveness in the genus Bremia.}, year = {2011}, keywords = {}, doi = {10.1016/j.funbio.2010.10.010}, url = {}, pmid = {}, journal = {Fungal Biology}, volume = {115}, number = {2}, pages = {102--111}, abstract = {Bremia lactucae is one of the economically most important pathogens in lettuce production. Recent molecular studies have shown Bremia lactucae (Peronosporales) to consist of several genetically distinct entities. However, as only few accessions from the same host have been investigated and it is generally believed that it is hardly possible to use morphological characteristics for species delimitation in Bremia, B. lactucae is still regarded as a sole species of Bremia causing downy mildew disease of the family Asteraceae. Therefore, multiple accessions of selected species that had been described decades ago, but have not been widely accepted, were investigated both on the basis of multi-gene molecular phylogenies and morphological characters. All previously described species included, B. microspora, B. ovata, B. saussureae, and B. sonchicola could be confirmed as highly distinct, host specific entities. Also morphological characterisitcs of their conidiophores and conidia allowed delimitation of the five species. Therefore, the wide species concept to merge all Bremia species on the Cichorioideae under B. lactucae is inappropriate. In addition, it could be shown that B. elliptica is phylogenetically distinct from the second species infecting the genus Lactuca, B. lactucae. It is therefore concluded that Bremia lactucae is most likely limited to Lactuca sativa and closely related species, and thus infections of unrelated wild Asteraceae weeds with Bremia are not posing a risk for lettuce production. The finding that Bremia lactucae is highly host specific might stimulate the search for durable resistance genes in genera closely related to the genus Lactuca and in divergent species of the genus itself.} }