5-Azacytidine, a DNA methyltransferase inhibitor, led to significant changes in the secondary metabolism of the plant endophytic fungus, Pestalotiopsis microspora. Analysis of the culture broth extract led to the isol...5-Azacytidine, a DNA methyltransferase inhibitor, led to significant changes in the secondary metabolism of the plant endophytic fungus, Pestalotiopsis microspora. Analysis of the culture broth extract led to the isolation of a new compound, 4＇-forrnamidophenyl-5-methoxybenzoate （1）, along with seven known polyketides, 4-hydroxybenzoic acid （2）, LL-P880ct （3）, 1＇-hydroxy-4-methoxy-6-pentyl-2H-pyran-2-one （4）, pestalotiollide B （5）, pestalotiopyrone G （6）, endocrocin （7） and 2＇-hydroxy- 6＇-hydroxymethyl-4＇-methylphenyl-2,6-dihydroxy-3-（2-isopentenyl）benzoate （8）. HPLC profiles revealed that all compounds except for 4 belonged to the newly induced secondary metabolites. In addition, all compounds were proved to be devoid of significant antifungal activity in the bioassays.展开更多
A DNA barcode is a short segment of sequence that is able to distinguish species. A barcode must ideally contain enough variation to distinguish every individual species and be easily obtained. Fungi of Nectriaceae ar...A DNA barcode is a short segment of sequence that is able to distinguish species. A barcode must ideally contain enough variation to distinguish every individual species and be easily obtained. Fungi of Nectriaceae are economically important and show high species diversity. To establish a standard DNA barcode for this group of fungi, the genomes of Neurospora crassa and 30 other filamentous fungi were compared. The expect value was treated as a criterion to recognize homologous sequences. Four candidate markers, Hsp90, AAC, CDC48, and EF3, were tested for their feasibility as barcodes in the identification of 34 well-established species belonging to 13 genera of Nectriaceae. Two hundred and fifteen sequences were analyzed. Intraand inter-specific variations and the success rate of PCR amplification and sequencing were considered as important criteria for estimation of the candidate markers. Ultimately, the partial EF3 gene met the requirements for a good DNA barcode: No overlap was found between the intra-and inter-specific pairwise distances. The smallest inter-specific distance of EF3 gene was 3.19%, while the largest intra-specific distance was 1.79%. In addition, there was a high success rate in PCR and sequencing for this gene (96.3%). CDC48 showed sufficiently high sequence variation among species, but the PCR and sequencing success rate was 84% using a single pair of primers. Although the Hsp90 and AAC genes had higher PCR and sequencing success rates (96.3% and 97.5%, respectively), overlapping occurred between the intraand inter-specific variations, which could lead to misidentification. Therefore, we propose the EF3 gene as a possible DNA barcode for the nectriaceous fungi.展开更多
基金National Natural Science Foundation(Grant No.31660251)Fundamental Research Funds for the Central Universities(Grant No.0903005203401)the Start-up Fund for the“Hundred Young-Talent Scheme”Professorship(Grant No.0236011104424)
文摘5-Azacytidine, a DNA methyltransferase inhibitor, led to significant changes in the secondary metabolism of the plant endophytic fungus, Pestalotiopsis microspora. Analysis of the culture broth extract led to the isolation of a new compound, 4＇-forrnamidophenyl-5-methoxybenzoate （1）, along with seven known polyketides, 4-hydroxybenzoic acid （2）, LL-P880ct （3）, 1＇-hydroxy-4-methoxy-6-pentyl-2H-pyran-2-one （4）, pestalotiollide B （5）, pestalotiopyrone G （6）, endocrocin （7） and 2＇-hydroxy- 6＇-hydroxymethyl-4＇-methylphenyl-2,6-dihydroxy-3-（2-isopentenyl）benzoate （8）. HPLC profiles revealed that all compounds except for 4 belonged to the newly induced secondary metabolites. In addition, all compounds were proved to be devoid of significant antifungal activity in the bioassays.
基金supported by the National Natural Science Foundation of China (Grant No. 31070015)the Special Project for Fundamental Research (Grant No. 2006FY120100) from Ministry of Science and Technology of Chinathe Knowledge Innovation Program of Chinese Academy of Sciences (Grant No. KSCX2-EW-J-6)
文摘A DNA barcode is a short segment of sequence that is able to distinguish species. A barcode must ideally contain enough variation to distinguish every individual species and be easily obtained. Fungi of Nectriaceae are economically important and show high species diversity. To establish a standard DNA barcode for this group of fungi, the genomes of Neurospora crassa and 30 other filamentous fungi were compared. The expect value was treated as a criterion to recognize homologous sequences. Four candidate markers, Hsp90, AAC, CDC48, and EF3, were tested for their feasibility as barcodes in the identification of 34 well-established species belonging to 13 genera of Nectriaceae. Two hundred and fifteen sequences were analyzed. Intraand inter-specific variations and the success rate of PCR amplification and sequencing were considered as important criteria for estimation of the candidate markers. Ultimately, the partial EF3 gene met the requirements for a good DNA barcode: No overlap was found between the intra-and inter-specific pairwise distances. The smallest inter-specific distance of EF3 gene was 3.19%, while the largest intra-specific distance was 1.79%. In addition, there was a high success rate in PCR and sequencing for this gene (96.3%). CDC48 showed sufficiently high sequence variation among species, but the PCR and sequencing success rate was 84% using a single pair of primers. Although the Hsp90 and AAC genes had higher PCR and sequencing success rates (96.3% and 97.5%, respectively), overlapping occurred between the intraand inter-specific variations, which could lead to misidentification. Therefore, we propose the EF3 gene as a possible DNA barcode for the nectriaceous fungi.
