The RAPD And Analysis Of ITS Sequences Aspergillus In Gansu

Aspergillus samples were collected from soil samples and insect samples of Donghuang,Wuwei,Zhangye,Lanzhou,Baiyin,Dingxi,Tianshui,Tianzhu and Wudu in Gansu province in March,2004.There were many kinds of Aspergillus in Gansu province. Aspergillus was identified according to morphology and molecular methods.The realationship of them was studied,too.There were four main results.Fristly, in the traditional classification and identification of the genus Aspergillus, it was difficult to identify species according to morphological characteristics because of the great number of species and the high similarity among them. With the analysis of RAPD and ITS (rDNA) sequences, this study was made of classification,identification and phylogeny of 14 species of Aspergillus,which could provide new information for the molecular phylogenetic study of genus.Secondly, in the RAPD profiles generated by 14 random primers,there were no RAPD bands sharing with all the 14 species,which revealed the abundant polymorphism among the tested isolates. Meantime,14 random primers could be stably amplified the genomic DNA from the tested strains and obtained 211 RAPD bands. There were 164 polymorphic loci and 77.73% was polymorphism. All the RAPD profiles could objectively show the realationships among the tested isolates.Thirdly, in the cluster analysis of the RAPD bands, the result showed that isolates of different species were clustered in low value of similarity coefficient by Between-groups linkage and similarity matrix.This result was almost consistent with the morphological studies, and also indicated the rationality and feasibility of the application of RAPD analysis in the identification of Aspergillus species.Finally, in this study, some similar species in morphology were chosen for ITS sequences analysis.ITS region(ITS1 and ITS2) and 5.8SrDNA of 6 isolates were amplified by PCR and sequenced.The analysis of all the aligned sequences by Mega 3.0 produced a most parsimonious phylogenetic tree.This result showed that the absolute distance among of them was over 11 base pairs,which was the normal range of different species.