Molecular Systematic Study Of Plant Pathogenic Fungi Of Botryosphaeriaceae

Botryosphaeriaceae(Botryosphaeriales,Dothideomycetes,Pezizomycotina,Ascomycota)is widely distributed.Species of Botryosphaeriaceae have diverse lifestyles as being saprophytic,parasitic or endophytic and play an important role in both ecological and living environment.They are also important plant pathogens which can cause a variety of plant diseases.Presently,the taxonomic status of Botryosphaeriaceae and their related taxa is unclear.Molecular phylogeny and morphological study are used in this research to identify the collected pathogenic Botryosphaeriaceae species.This research provides references for processing the fungal taxonomy of pathogenic species in Botryosphaeriaceae.The samples in this study were collected from China(Guizhou,Guangxi,Yunnan,Sichuan,Jiangsu)and Thailand(Phayao,Chiang Rai,Nan)from September2017 to August 2020.All the stains were isolated from leaves,stems,and fruits of plants with disease symptoms.More than 800 samples with lesions were collected.The fungi isolated from the samples were identified using both molecular phylogenetic and morphological methods.124 strains of Botryosphaeriaceae were isolated from 63 host samples which include 34 plants belonging to 27 families along with some unidentified hosts.Among the 124 strains,7 genera were recognized,viz.15 isolates in Botryosphaeria,69 isolates in Lasiodiplodia,27 isolates in Neofusicoccum,4 isolates in Cophinforma,4 isolates in Diplodia,3 isolates in Neodeightonia,and 2 isolates in Tiarosporella.1 species is reported for the first time in China and 3 species for the first time in Thailand.Based on multigene polygenetic analyses(SSU,ITS,LSU,tef1,tub2)and morphological study,19 species were identified,of which 3 are new species(B.salii,B.osmanthuse and L.syzygii);16 are previously described species(Botryosphaeria dothidea ? Botryosphaeria minutispermatia ? Botryosphaeria auasmontanum ? Lasiodiplodia theobromae ?Lasiodiplodia mahajangana ? Lasiodiplodia iraniensis ? Lasiodiplodia pseudotheobromae ? Lasiodiplodia chinensis ? Lasiodiplodia thailandica ?Neofusicoccum parvum ? Cophinforma mamane ? Cophinforma atrovirens ?Neodeightonia rattanica?Neodeightonia palmicola?Diplodia seriata and Diplodia mutila).And 6 species remained unidentified.In this study,though identification of Botryosphaeriaceae fungi associate with plant disease that collected from 5 provinces of China and 3 provinces of Thailand,the following conclusion are came:(1)tef1 gene can be used as a preferred barcode gene to identify species of Botryosphaeriaceae,and the combination of ITS,tef1 and tub2 gene can be used for phylogenetic analyses to solve the classification problem of this family;(2)The fungi of the Botryosphaeriaceae are widely distributed and host diverse.The basic understanding of the phylogenetic relationship and host diversity of Botryosphaeriaceae in these areas is of great significance for the prevention and control of plant diseases caused by the species of Botryosphaeriaceae.