Research Area of Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, Vienna, Austria.
PLoS One. 2010 Feb 12;5(2):e9191. doi: 10.1371/journal.pone.0009191.
Trichoderma reesei, a mitosporic green mould, was recognized during the WW II based on a single isolate from the Solomon Islands and since then used in industry for production of cellulases. It is believed to be an anamorph (asexual stage) of the common pantropical ascomycete Hypocrea jecorina.
METHODOLOGY/PRINCIPAL FINDINGS: We combined molecular evolutionary analysis and multiple methods of phenotype profiling in order to reveal the genetic relationship of T. reesei to H. jecorina. The resulting data show that the isolates which were previously identified as H. jecorina by means of morphophysiology and ITS1 and 2 (rRNA gene cluster) barcode in fact comprise several species: i) H. jecorina/T. reesei sensu stricto which contains most of the teleomorphs (sexual stages) found on dead wood and the wild-type strain of T. reesei QM 6a; ii) T. parareesei nom. prov., which contains all strains isolated as anamorphs from soil; iii) and two other hypothetical new species for which only one or two isolates are available. In silico tests for recombination and in vitro mating experiments revealed a history of sexual reproduction for H. jecorina and confirmed clonality for T. parareesei nom. prov. Isolates of both species were consistently found worldwide in pantropical climatic zone. Ecophysiological comparison of H. jecorina and T. parareesei nom. prov. revealed striking differences in carbon source utilization, conidiation intensity, photosensitivity and mycoparasitism, thus suggesting adaptation to different ecological niches with the high opportunistic potential for T. parareesei nom. prov.
Our data prove that T. reesei belongs to a holomorph H. jecorina and displays a history of worldwide gene flow. We also show that its nearest genetic neighbour--T. parareesei nom. prov., is a cryptic phylogenetic agamospecies which inhabits the same biogeographic zone. These two species thus provide a so far rare example of sympatric speciation within saprotrophic fungi, with divergent ecophysiological adaptations and reproductive strategies.
里氏木霉，一种有丝分裂的绿霉菌，于第二次世界大战期间基于所罗门群岛的一个单一分离株被发现，此后一直用于工业生产纤维素酶。它被认为是常见的泛热带子囊菌 Hypocrea jecorina 的无性阶段（无性阶段）。
方法/主要发现：我们结合了分子进化分析和多种表型分析方法，以揭示 T. reesei 与 H. jecorina 的遗传关系。结果表明，以前通过形态生理学和 ITS1 和 2（rRNA 基因簇）条形码鉴定为 H. jecorina 的分离株实际上包含几个种：i）H. jecorina/T. reesei 严格意义上包含大多数在枯木上发现的有性阶段（有性阶段）和 T. reesei QM 6a 的野生型菌株；ii）T. parareesei nom. prov.，其中包含所有从土壤中分离出的无性阶段的菌株；iii）和另外两个只有一两个分离株的假设新种。重组的计算机测试和体外交配实验表明 H. jecorina 有性繁殖的历史，并证实了 T. parareesei nom. prov. 的克隆性。这两个种的分离株在世界范围内的泛热带气候带中都有发现。H. jecorina 和 T. parareesei nom. prov. 的生态生理学比较表明，在碳源利用、分生孢子形成强度、光敏感性和真菌寄生方面存在显著差异，因此表明适应不同的生态位，具有高机会性的 T. parareesei nom. prov.。
我们的数据证明 T. reesei 属于 Holomorph H. jecorina，并显示出全球基因流动的历史。我们还表明，它最近的遗传邻居——T. parareesei nom. prov.，是一个隐生无性种，栖息在相同的生物地理区。这两个种因此提供了一个迄今为止罕见的例子，即在腐生真菌中，具有不同的生态生理学适应性和繁殖策略的同域物种形成。
