Data from: Beyond animals and plants: dynamic maternal effects in the fungus Neurospora crassa

Maternal effects are widely documented in animals and plants, but not in fungi or other eukaryotes. A principal cause of maternal effects is asymmetrical parental investment in a zygote, creating greater maternal versus paternal influence on offspring phenotypes. Asymmetrical investments are not limited to animals and plants, but are also prevalent in fungi and groups including apicomplexans, dinoflagellates, and red algae. Evidence suggesting maternal effects among fungi is sparse and anecdotal. In an experiment designed to test for maternal effects across sexual reproduction in the model fungus Neurospora crassa, we measured offspring phenotypes from crosses of all possible pairs of 22 individuals. Crosses encompassed reciprocals of 11 mating-type “A” and 11 mating-type “a” wild strains. After controlling for the genetic and geographic distances between strains in any individual cross, we found strong evidence for maternal control of perithecia (sporocarp) production, as well as maternal effects on spore numbers and spore germination. However, both parents exert equal influence on the percentage of spores that are pigmented, and size of pigmented spores. We propose a model linking the stage-specific presence or absence of maternal effects to cellular developmental processes: effects appear to be mediated primarily through the maternal cytoplasm, and, after spore cell walls form, maternal influence on spore development is limited. Maternal effects in fungi, thus far largely ignored, are likely to shape species’ evolution and ecologies. Moreover, the association of anisogamy and maternal effects in a fungus suggests maternal effects may also influence the biology of other anisogamous eukaryotes.母性效应（Maternal effects）在动物与植物中已有广泛报道，但在真菌或其他真核生物中尚未有系统性记录。母性效应的核心成因是双亲对合子的不对称投入，由此使得母体对后代表型的影响显著强于父体。这种不对称的资源投入并非仅局限于动植物类群，在真菌以及顶复门原虫、甲藻、红藻等类群中也普遍存在。目前有关真菌存在母性效应的证据既稀缺又多为零散的轶事性报道。本研究以模式真菌粗糙脉孢霉（Neurospora crassa）为研究对象，设计了检验其有性生殖过程中母性效应的实验：对22个野生菌株的所有可能交配组合开展杂交，涵盖11个交配型“A”与11个交配型“a”的野生菌株的互交组。在控制单次杂交中菌株间的遗传距离与地理距离后，我们发现了确凿证据，表明母体对子囊果（perithecia，sporocarp）的形成具有调控作用，同时母体还会对孢子数量与孢子萌发率产生影响。不过，双亲对有色孢子的占比以及有色孢子的大小均起到了同等程度的影响。我们提出了一个将母性效应的阶段特异性存在与否与细胞发育过程相关联的模型：这类效应主要通过母体细胞质介导，而在孢子细胞壁形成后，母体对孢子发育的影响会受到显著限制。迄今为止长期被忽视的真菌母性效应，极有可能会对物种的演化与生态塑造产生重要作用。此外，在真菌中发现的异配生殖（anisogamy）与母性效应的关联，提示母性效应或许也会对其他异配生殖真核生物的生物学特征产生影响。