Data from: Correlated evolution of senescence and ephemeral substrate use in the Sordariomycetes

Evolutionary theory predicts that senescence – a decline in reproduction and survival with increasing age - can evolve as a trade-off between the investment in reproduction on one side and in somatic maintenance and repair on the other side. The ecology of a species is crucial here, since it provides the external causes of death that determine the statistical limit to a species’ lifespan. Filamentous fungi are generally believed to be non-senescent, and there are indeed spectacular examples of very old fungal individuals in nature. Yet, for some fungi the growth conditions are ephemeral and therefore senescence is expected to have evolved, like in the coprophilic Podospora anserina, the only well-studied filamentous fungus with intrinsic senescence. Here we hypothesize that rapid senescence is more common in fungi than generally believed and that the phylogenetic distribution of senescence correlates with its ecology. We examined a set of Sordariomycetes for their lifespan and constructed phylogenies based on several nuclear sequences. Part of the strains were from the CBS culture collection, originally isolated from various substrates, some of which ephemeral. In addition we isolated new strains from short-lived substrates. Senescence was observed throughout the phylogeny. Correlation tests support the hypothesis that in the Sordariomycetes senescence is a trait that has arisen as an evolved adaptation to ephemeral substrates, and that it has evolved repeatedly and independently along the phylogeny.

演化理论（Evolutionary theory）预测，衰老——即随着年龄增长而出现的繁殖能力与生存能力下降——可作为繁殖投入与体细胞维持和修复投入之间的权衡而演化。物种的生态学特征在此至关重要，因为它提供了决定物种寿命统计上限的外部死亡原因。丝状真菌（filamentous fungi）通常被认为不具有衰老特性，自然界中也确实存在极为古老的真菌个体的惊人实例。然而，对于部分生长环境短暂的真菌而言，衰老应当已经演化产生，例如嗜粪的Podospora anserina——这是目前唯一被充分研究的具有内在衰老特性的丝状真菌。本研究假设，快速衰老在真菌中比普遍认知的更为常见，且衰老的系统发育分布与其生态学特征相关。我们检测了一组粪壳菌纲（Sordariomycetes）真菌的寿命，并基于多个核基因序列构建了系统发育树。部分菌株来自CBS菌种保藏中心（CBS culture collection），最初分离自多种基质，其中部分基质的存在周期短暂。此外，我们还从短生命周期基质中分离得到了新的菌株。本研究在整个系统发育树中均观察到了衰老现象。相关性检验支持如下假说：在粪壳菌纲真菌中，衰老是一种演化而来的、适应短暂基质环境的性状，且该性状在系统发育过程中多次独立演化产生。