Studies On The Genus Septobasidium (Septobasidiaceae) From China

The genus Septobasidium, with a putatively altruistic-mutualistic relationship with its host scale insects, is an important pathogen. These fungi, distributed in some provinces around the south upper reaches of the Yellow River, around the reaches of Yangtze River, near coastal line or on island, produce patches covering the surface of branches or leaves of plant, and gradually lead the branches or leaves to death. It is identified that these species are associated with plant affiliated to56families, and are associated with scale insects affiliated to8genera. The preferred host trees belong to three families, such as Lauraceae, Rutaceae and Moraceae; while the most common host insect scales belong to genera Aulacaspis and Psuedaulacaspis.Field investigations and biodiversity studies were carried out in Yunnan, Sichuan, Hainan, Anhui and some other areas in south China; more than200fresh specimens were collected and identified. And2specimens of Septobasidium previously deposited in the HMAS were re-examined. Based on morphological and anatomical analyses,30species were identified and described, including9known species,15new species and6new Chinese records, which updated the previous fungal records of China. The6new records were S. atropunctum Couch,S. conidiophorum Couch ex L.D. Gomez&Henk, S. henningsii Pat., S. pseudopedicellatum Burt and S. rhabarbarinum (Mont.) Bres..11new species had already been published, including S. albiziae, S. atalantiae, S. glycosmidis, S. saurauiae, S. elaeagni, S. hydrangea, S. yunnanense, S. capparis, S. reevesiae, S. dacrydii and S.sichuanens.4new species are still unpulished, including S. cotoneaster, S. euonymi, S. symploci and S. hoveniae.Phylogeny of selected members of the genus Septobasidium was also under research via methods of ME (minimum evolution) and MP (maximum parsimony), based on partial sequences of ITS regions and the complete sequence of ribosome5.8S rDNA. There were total44ITS sequences from24species of the genus Septobasidium. Among24taxa of the Septobasidium tested,2distinct clades were recognized. Moreover, at least three distinct groups could be recognized among species with basidia of4cells, based on the relationships between molecular data and anatomical characters. The molecular data partially established the main anatomic characteristics frequently used by traditional taxonomy, including probasidia persistent or not, cell numbers and shapes of basidia and pillars high or short et al.