The Phylogenetic Study Of Phyllosticta In Southwest China

The genus Phyllosticta is a fungal group including important plant pathogens, some of which can cause significant economic importance, and some are regarded as quarantine diseases as well. For a long time, the researchers felt confused about the taxonomic concepts since Phyllosticta was erected. In order to get a good understanding of Phyllosticta diversity in Southwestern China, the specimens were collected from Guizhou, Yunnan, Sichuan and Chongqing provinces. The morphological and phylogenetic studies are used to identify the species, as well as the diversity study.We totally collected more than 300 plant diseased samples from four provinces. After isolation and purification, 107 Phyllosticta isolates were obtained during 2010 to 2014, DNA of four gene regions, viz. ITS, ACT, GPDH and TEF were sequenced for the phylogenetic analysis, meanwhile their morphological characters, such as conidiomata, conidiogenous cells, conidia, mucoid sheaths and apical appendages were also studied. Based on phylogeny and morphology, these 107 isolates were indentified as 12 species, 6 are novelty to science(namely P. musaechinensis S.P. Wu, Z.Y. Liu & K.D. Hyde sp. nov, P. buxichinensis Z.Y. Liu & K.D. Hyde sp. nov, P. guizhouensis S.P. Wu & Z.Y. Liu, P. pittosporicola Z.Y. Liu & K.D. Hyde sp. nov, P. liriodendricola S.P. Wu & Z.Y. Liu sp. nov and Phyllositcta taxicola S. P. Wu & Z.Y. Liu, sp. nov.). 3 of which are chinese records species(5 isolates are P. partricuspidatae N. zhou & L. Cai,4 isolates are G. musicola N.F. Wulandari, L. Cai & K.D. Hyde, 3 isolates are P. citribraziliensis C. Glienke & Crous). 3 of which are reported species(82 isolates are Phyllosticta capitalensis Henn., one isolate is P. musarum(Cook) van der Aa and one isolate is P. citriasia Wulandari).Based on the phylogenetic and morphological studies, the results showed that the fungus which caused Japan fatsia grey spot and Ginkgo leaf spot disease was P. capitalensis, which was the first study to provide powerful evidence and give a better understanding for the disease control and treatment. To explicit the relationship between the Phyllosticta spp. and their hosts, 203 isolates of 67 species were studie. All Phyllosticta isolates obtained from Liliopsidales can be assigned 5 clades, and the indexs of Shannon and Simpson are 1.357 and 0.732. Phyllosticta capitalensis was shown to be widespread fungus, of which 54 isolates were obtained from 24 different plant host families. There are only few species which possessed host specific, however, it is still unclear whether the Phyllosticta species are generalists or host-specific, for many of the species are also found as endophytes. Therefore it is some confused to identify different species only based on the host. This study detailed the diversity of Phylloscticta species in southwestern China, and the relationship between this fungal group and the hosts. Our study has an important value in the disease control and resources application.