Department of Genetics, Faculty of Biology, University of Athens, Athens, Greece.
BMC Microbiol. 2010 Jun 16;10:174. doi: 10.1186/1471-2180-10-174.
The entomopathogenic fungi of the genus Beauveria are cosmopolitan with a variety of different insect hosts. The two most important species, B. bassiana and B. brongniartii, have already been used as biological control agents of pests in agriculture and as models for the study of insect host - pathogen interactions. Mitochondrial (mt) genomes, due to their properties to evolve faster than the nuclear DNA, to contain introns and mobile elements and to exhibit extended polymorphisms, are ideal tools to examine genetic diversity within fungal populations and genetically identify a species or a particular isolate. Moreover, mt intergenic region can provide valuable phylogenetic information to study the biogeography of the fungus.
The complete mt genomes of B. bassiana (32,263 bp) and B. brongniartii (33,920 bp) were fully analysed. Apart from a typical gene content and organization, the Beauveria mt genomes contained several introns and had longer intergenic regions when compared with their close relatives. The phylogenetic diversity of a population of 84 Beauveria strains -mainly B. bassiana (n = 76) - isolated from temperate, sub-tropical and tropical habitats was examined by analyzing the nucleotide sequences of two mt intergenic regions (atp6-rns and nad3-atp9) and the nuclear ITS1-5.8S-ITS2 domain. Mt sequences allowed better differentiation of strains than the ITS region. Based on mt and the concatenated dataset of all genes, the B. bassiana strains were placed into two main clades: (a) the B. bassiana s. l. and (b) the "pseudobassiana". The combination of molecular phylogeny with criteria of geographic and climatic origin showed for the first time in entomopathogenic fungi, that the B. bassiana s. l. can be subdivided into seven clusters with common climate characteristics.
This study indicates that mt genomes and in particular intergenic regions provide molecular phylogeny tools that combined with criteria of geographic and climatic origin can subdivide the B. bassiana s.l. entomopathogenic fungi into seven clusters with common climate characteristics.
球孢白僵菌属的虫生真菌分布广泛，具有多种不同的昆虫宿主。两个最重要的物种，白僵菌和布氏白僵菌，已经被用作农业害虫的生物防治剂，以及昆虫宿主-病原体相互作用的研究模型。线粒体（mt）基因组由于其进化速度快于核 DNA、含有内含子和移动元件以及表现出扩展的多态性等特性，是研究真菌种群内遗传多样性和遗传鉴定物种或特定分离株的理想工具。此外，mt 基因间区可以提供有价值的系统发育信息来研究真菌的生物地理学。
对白僵菌（32263bp）和布氏白僵菌（33920bp）的完整 mt 基因组进行了全面分析。除了典型的基因组成和组织外，与近亲相比，白僵菌 mt 基因组包含几个内含子，并且基因间区更长。通过分析两个 mt 基因间区（atp6-rns 和 nad3-atp9）和核 ITS1-5.8S-ITS2 结构域的核苷酸序列，研究了来自温带、亚热带和热带生境的 84 株白僵菌（主要为白僵菌（n=76））种群的系统发育多样性。mt 序列比 ITS 区能更好地区分菌株。基于 mt 和所有基因的串联数据集，白僵菌菌株被分为两个主要分支：（a）白僵菌 s.l.和（b）“pseudobassiana”。分子系统发育与地理和气候起源标准的结合首次表明，在昆虫病原真菌中，白僵菌 s.l.可分为七个具有共同气候特征的聚类。
本研究表明，mt 基因组，特别是基因间区提供了分子系统发育工具，结合地理和气候起源标准，可以将白僵菌 s.l.昆虫病原真菌分为七个具有共同气候特征的聚类。
