The Resource And Diversity Of Endophytic Pestalotiopsis Of Mangrove In Southern China

Pestalotiopsis species is an important group of endophytic fungi. The diversity of endophytic Pestalotiopsis species was investigated in southern China.Endophytic Pestalotiopsis produced abundant valuable metabolites including antltumor,antifungal and antibacterial substances.As a part work of the National Natural Science Foundation of China Grants item"Resources and diversity of endophytic Pestalotiopsis in Mangrove and taxonomic study for Pestalotiopsis", the investigation of resource and diversity of endophytic Pestalotiopsis in mangroves was carried out in Guangdong ,Guangxi and Hainan.By comparison of taxonomic characters's stability of the conidia on different days and also from different asexual gengrations, ITS and beta-tubulin gene sequences of representative strains were amplified , the significance of each characterisistic of the conidia was explored. The main results were summarized as follows:1. Species of mangrove plant endophytic Pestalotiopsis in Guangdong and GuangxiIn a survey of endophytic Pestalotiopsis species in mangrove plants in Techengdao of Guangdong province and Shankou of Guangxi province from 2009 to 2010,a total of 76 Pestalotiopsis species belonging to 23 families were isolated from 19 mangrove plants.2. Diversity of mangrove plant endophytic Pestalotiopsis in Guangdong,Guangxi and HainanColonization frequencies of endophytic Pestalotiopsis varied with the place of mangrove plants. For example, Colonization frequencies of endophytic Pestalotiopsis in Kandelia candel of Guangdong was the highest, Colonization frequencies of endophytic Pestalotiopsis in Rhizophora stylosa of Hainan was the highest, but there was no significant difference of the colonization frequencies of endophytic Pestalotiopsis in Bruguiera gymnorrhiza of Guangdong ,Guangxi and Hainan.Colonization frequencies of endophytic Pestalotiopsis varied with different familes of host plants. For example, Colonization frequencies of endophytic Pestalotiopsis in Kandelia candel and Sonneratia caseolaris in Hainan was 8.9%, but no endophytic Pestalotiopsis were isolated from Avicennia mariana in Hainan.The colonization in Kandelia candel of Guangxi was higher than other mangrove plants, which was 20%.The species diversity of endophytic Pestalotiopsis is closely related with their host plants and the place of plants. 27 species of endophytic Pestalotiopsis were isolated from 10 familes of host plants in Hainan, 12 species of endophytic Pestalotiopsis were isolated from 4 familes of host plants in Guangdong, 18 species of endophytic Pestalotiopsis were isolated from 7 familes of host plants in Guangxi,but 3 species in Bruguiera gymnorrhiza, 1 species in Avicennia mariana.Richness index of endophytic Pestalotiopsis had no correlation with Shannon-Wiener index, but had closely correlation with evenness index.3.Taxonomic characters of the genus PestalotiopsisBy comparison of taxonomic characters's stability of the conidia on different days and also from different asexual gengrations, The length and width of conidia and the length of apical appendages were relatively stable so that they could be used as taxonomic characters. The pigmentation of median cells of conidia in Pestalotiopsis species was not stable on different days.4.Molecular phylogenetics of Pestalotiopsis A molecular phylogenetic tree was generated with ITS regions (ITS1, 5.8S and ITS2) and beta-tubulin 2 gene (tub2) of 76 Pestatotiopsis strains belonging to 29 species. Pestalotiopsis strains were firstly divided into two branches X and Y:''umber to fuliginous"as in group X,''brown to olivaceous"as in groups Y. X branch was further divided into 2 obvious subbranches(a and b) , b subbranch included Pestalotiopsis species with knobbed apical appendages,hut a did not include.Y branch was further divided into 2 subbranehes(c and d), All strains of d subbranche were different in the length of conidia.According to the phylogenetic tree, The length and width of conidia and the length of apical appendages were not fit as the taxonomic characters.