Bipolaris species are important plant pathogens with a worldwide distribution in tropical and temperate environments. Species recognition in Bipolaris has been problematic due to a lack of molecular data from ex-type cultures, the use of few gene regions for species resolution and overlapping morphological characters. In this study, we evaluate the efficiency of different DNA barcodes in species delimitation in Bipolaris by phylogenetic analyses, Automatic Barcode Gap Discovery and Objective Clustering. GAPDH is determined to be the best single marker for the genus. These approaches are used to clarify the taxonomic placement of all sequences currently named as Bipolaris in GenBank based on ITS and GAPDH gene sequence data. In checking various publications, we found that the majority of new host records of fungal species published in the Plant Disease journal from 2010 to 2019 were based on BLAST searches of the ITS sequences and up to 82% of those records could be erroneous. Therefore, relying on BLAST searches from GenBank to name species is not recommended. Editorial boards of journals and reviewers of new record papers should be aware of this problem. In naming Bipolaris species, whether new or known, it is recommended to perform phylogenetic analyses based on GAPDH using the correct taxon sampling for accurate results and the species relationship should have reliable statistical support. At least two new species are represented by molecular data in GenBank and we provide an updated taxonomic revision of Bipolaris. We accept 45 species in Bipolaris and notes are provided for all the species including hosts and geographic distribution.

中文翻译：

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描绘双极生物中物种的多相方法

双极类是重要的植物病原体，在热带和温带环境中分布广泛。由于缺乏来自前型培养物的分子数据，使用很少的基因区域进行物种解析和重叠的形态特征，双极性物种的物种识别一直存在问题。在这项研究中，我们通过系统发育分析，自动条形码空位发现和客观聚类来评估双极性物种在物种界定中不同DNA条形码的效率。GAPDH被确定为该属的最佳单一标记。这些方法用于阐明当前命名为Bipolaris的所有序列的分类学位置GenITS中基于ITS和GAPDH基因序列数据的数据。在检查各种出版物时，我们发现，2010年至2019年在《植物病》杂志上发表的大多数真菌物种新宿主记录均基于ITS序列的BLAST搜索，其中多达82％的记录可能是错误的。因此，不建议依靠GenBank的BLAST搜索来命名物种。期刊编辑委员会和新记录论文的审阅者应注意此问题。在命名双极物种，无论是新物种还是已知物种，建议使用正确的分类单元采样基于GAPDH进行系统发育分析，以获取准确的结果，并且物种之间的关系应具有可靠的统计支持。GenBank中的分子数据代表了至少两个新物种，我们提供了Bipolaris的最新分类学修订。我们在Bipolaris接受45种，并提供了所有物种的注释，包括寄主和地理分布。