木霉属补充DNA条形码筛选

木霉属真菌是一类重要的生物资源，在工农业、环境保护等方面具有较高经济价值，对其进行快速、准确的物种鉴定兼具理论意义和应用前景。以木霉属35个概念清晰的种为材料，选择ITS、rpb2和 tef1作为候选基因序列，利用TaxonGap对231个序列片段进行分析，将种内与种间序列差异以及序列获取难易程度作为评价指标，筛选该属的补充条形码片段。结果表明，rpb2具有适宜的种内与种间序列差异，其最小的种间差异（2.48%），大于最大种内差异（1.8%），种内、种间遗传距离存在明显的间隔区，并且该基因序列具有较高的PCR扩增与测序成功率（94.4%）；ITS和tef1基因序列的种内与种间序列差异之间存在交叉重叠。因此建议rpb2作为木霉属的补充DNA条形码序列。

Selection of a supplementary DNA barcode for the genus Trichoderma (Hypocreales,Ascomycota)

Recent studies suggest that the genus Trichoderma is economically important and of high species diversity. Correct identification becomes critical for basic and applied researches of this fungal group. For accurate and rapid species identification of the genus, three DNA markers, ITS, rpb2 and tef1, were selected and evaluated as candidate DNA barcodes. Adequate intra- and inter-specific variations and efficiency of PCR and sequencing were considered as important criteria. A total of 231 sequences from 35 well-established Trichoderma species were analyzed via the programs TaxonGap. Our results suggest that the partial rpb2 gene met the requirements for an ideal DNA barcode, i.e. no overlap occurred between the intra- and inter-specific pairwise distances. The minimum inter-specific variation (2.48%) of rpb2 gene was greater than the maximum intra-specific variation (1.8%), and the PCR and sequencing rate reached 94.4%. As to the other two markers, overlapping occurred between the intra- and inter-specific variations, which may lead to misidentification. The rpb2 gene is thus proposed as a supplementary barcode for the genus Trichoderma.