Department of Genetics, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa.
PLoS One. 2018 Mar 5;13(3):e0192517. doi: 10.1371/journal.pone.0192517. eCollection 2018.
Homothallism (self-fertility) describes a wide variety of sexual strategies that enable a fungus to reproduce in the absence of a mating partner. Unisexual reproduction, a form of homothallism, is a process whereby a fungus can progress through sexual reproduction in the absence of mating genes previously considered essential for self-fertility. In this study, we consider the molecular mechanisms that allow for this unique sexual behaviour in the saprotrophic ascomycete; Huntiella moniliformis. These molecular mechanisms are also compared to the underlying mechanisms that control sex in Huntiella omanensis, a closely related, but self-sterile, species. The main finding was that H. omanensis displayed mating-type dependent expression of the a- and α-pheromones. This was in contrast to H. moniliformis where both pheromones were co-expressed during vegetative growth and sexual development. Furthermore, H. moniliformis also expressed the receptors of both pheromones. Consequently, this fungus is likely able to recognize and respond to the endogenously produced pheromones, allowing for self-fertility in the absence of other key mating genes. Overall, these results are concomitant with those reported for other unisexual species, but represent the first detailed study considering the unisexual behaviour of a filamentous fungus.
同宗配合（自育性）描述了广泛的性策略，使真菌能够在没有交配伙伴的情况下繁殖。单性生殖，即同宗配合的一种形式，是一种真菌在没有以前被认为对自育性至关重要的交配基因的情况下，就能进行有性生殖的过程。在这项研究中，我们考虑了允许这种独特的有性行为在腐生子囊菌中发生的分子机制；Huntiella moniliformis。这些分子机制也与控制亲缘关系密切但自育性的 Huntiella omanensis 中性别控制的潜在机制进行了比较。主要发现是，H. omanensis 显示出与交配型相关的 α-和 α-信息素的表达。这与 H. moniliformis 形成鲜明对比，在 H. moniliformis 中，两种信息素在营养生长和有性发育过程中都共同表达。此外，H. moniliformis 还表达了两种信息素的受体。因此，这种真菌可能能够识别和响应内源性产生的信息素，从而在没有其他关键交配基因的情况下实现自育性。总的来说，这些结果与其他单性生殖物种的报告一致，但代表了首次详细研究丝状真菌的单性生殖行为。
