Taxonomic And Molecular Systematic Study On Dematiaceae Fungi: Ulocladium, Stemphylium And Alternaria

Molecular systematic analysis is a basic method of bioinformatics, which is used for analyzing molecular evolution pattern/direction/speed and all kinds of molecular mechanism which effect the construction and function of genome. The main aim of systematic analysis is to construct phylogenetic tree based on molecular data, and infer branchs'pattern of a certain group. The construction method which had been developed now includes parsimony method, compatibility method, distance matrix method, maximum likelihood method et al. This study is about the molecular systematic analysis on type spcecies of phytopathogenic Fungi: Ulocladium, Stemphylium and Alternaria using parsimony method and neighbor-joining method of PAUP software. A new mean of systematic method based on homologous comparison of gene sequences is established for taxonomic study of these fungi. Combination of morphological and molecular systematic methods is introduced in systematic taxonomy, which complement and revise the modern taxonomic system of these fungi. Continuing collecting the fungal cultures of Ulocladium, Stemphylium and Alternaria from all kinds of hosts, geographical distribution, circumstance based on forepart study of fungal resource laboratory of plant pathology department. 8 cultures of Ulocladium, 64 cultures of Stemphylium were separated from more than 1200 specimens from Sichuan, Chongqing, Guizhou, Yunnan and Shandong provinces. Two new species, Ulocladium capsicum and Stemphylium subglobuliferum, were identified, described and released. The ITS of rDNA and gpd (glyceraldehyde-3-phosphate dehydrogenase) are amplified by PCR and used to construct phylognetic tree to illustrate the systematic status of new species because the morphological taxonomic characters of conidia is not stable. The phylogenetic trees are also used to revise the taxonomic system of U.atrum group and U.chartarum group of Ulocladium genera, A.alternata group and A.infectoria group of Alternaria genera: 1. According to the character whether the conidia in chains and the systematic evidence, separate Ulocladium genera into two distinct...