| Fungi are a group of eukaryotes with many species and very rich diversity. There are approximately1.5million species, of which only about80,000species have been described so far. Fungi are closely related with the human. Some fungi can increased fertility of soil and promote the growth and development of crops, but some fungi may cause crop disease so that no yields or seeds are gathered; some fungi can induced the development of roots of forests and promote their growth, while the other can destroy them; some fungi use grape and some fruits making wine, and the other will make grape and fruit decay; some fungi can be used to product antibiotics by fermentation and save billions of human’s life, but some fungi invade our body and make us ill even die; we use fungi to product lots of delicious food in our daily life, however some fungi can make food rot and produce toxins which cause food poisoning. It becomes mycologist’s endeavor how to make full use of fungal benifits and to overcome the disadvantage of fungi.In the fungi Kingdom, no other genera than Aspergillus there are also a large number of Aspergillus species are harmful to humans and of great significance in biological medicine and industry. For example, Aspergillus nidulans is a key model system of genetics and cell biology of fungi, Aspergillus niger is widely used in the production of citric acid in fermentation industry, and Aspergillus oryzae plays a key role in the process of fermentation in traditional sauce and soft drinks industry. On the other hand, Aspergillus flavus produces the carcinogenic substance aflatoxin, Aspergillus fumigatus and Aspergillus terreus are two representatives of the most pathogens of human and animal in the damaged condition of the immune system.With the completement of more and more genomes of organisms sequenced, comparative genomics, which clarify various biogenome base pairs in the DNA sequences of Genomics information and decode the relevant genetic information, and compare the known genes and their structure, understand the function of the gene, expression and regulation mechanism of species evolution, has become an integral discipline of biological and medical research. Compared to other eukaryotic genome, fungal genome is relatively simple, easy to be sequencing and annotating, and easy to genetic manipulation and gene modification. Therefore, fungi have become the best model organism in the eukaryotic genome research. Fungal genomics research can provide information on many important aspects such as fungal phylogeny, species identification and evolution, insights into gene function, the medicinally targeted genes and development of therapeutics, and so on.To accelerate the pace of the research of fungal genomics, fungal genome initiative (FGI) was launched in2000by the United States Institute of Broad and other fungal institutions, which is aimed at promoting the important role in representative species of the fungi genome sequencing in medicine, agriculture and industry. In February2002, FGI published its first white paper including15fungal genome projects. In June2003, the second white paper was published, in which44species of fungi are listed as a sequencing goals and among them,10genera such as Aspergillus:Penicillium, Aspergillus, Histoplasma, Coccidioides, Fusarium, Neurospora, Candida, Schizosaccharomyces and Puccinia have a priority in sequencing. As to February14,2012,124kinds of fungal genome in whole have been sequenced completely, another59has been sequencing.The studes are based on the completement of genome sequences of8representatives Aspergillus:A. flavus, A. oryzae, A. terreus, A. niger, N. fischeri, A. fumigatus, A. clavatus and A. nidulans. We made local blast and designed specific primer representively in their homologous sequences as molecular identification marker by establishing local database. According to earlier related reports, the conserved gene ribosomal RNA genes and RPB1, RPB2, TEF1, cmd, β-tubulin gene of fungi are shown as the candidates of these studies. Limited to the workload and time, RPB2gene of Aspergillus fumigatus was analysized and specific primers were designed to develop into means of a rapid molecular identification of Aspergillus fumigatus.Firstly, download the RPB2gene of A. fumigatus online, blast its sequence with local database, found the RPB2homologous gene of8species of Aspergillus, then extract out8RPB2gene of Aspergillus from local database by Perl language one by one, by mutiblasting Genomic sequences of8Aspergillus imported into ClustalX, used A. fumigatus for template, in its conservative regions, we design five specific primers, eventually by PCR, we detect out only two primers in A. fumigatus which can amplify the single electrophoresis strand while in other seven Aspergillus without any stripes can be found. Therefore, this two pairs of primers can be preliminary, as the specific molecular markers of Aspergillus fumigatus.We could search out2or3specific molecular markers of Aspergillus flavus with the same method and then collect as many other Aspergillus and species of Fungi not studied in the paper as possible to make further PCR validation for the specific molecular markers found in A. fumigatus and A. flavus.To identify A. fumigatus and A. flavus by above specific molecular markers, on the one hand, it provides a new, simple, convenient way of the detection in pathlogens, especially in import and export quarantine, will reduce many economic loss not necessary for us, reduce many livestock disease; on the other hand, Blastall, which combined comparative genomics and the local genomic database, is expected to be a fast, effective method to study gene evolution, species identification and species occurs. |
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