Department of Plant Pathology, University of Wisconsin, Madison, Wisconsin, USA.
Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, USA.
mBio. 2022 Dec 20;13(6):e0275422. doi: 10.1128/mbio.02754-22. Epub 2022 Nov 14.
Hydrophobins are small amphipathic surface proteins found exclusively in fungi. In filamentous ascomycetes, one conserved role of a subset of hydrophobins is their requirement for spore dispersal. Other contributions of these proteins to fungal biology are less clear and vary across genera. To determine the functions of hydrophobins in the biology and virulence of this fungus, we created seven single mutants and a septuple-deletion mutant (Δ) of the entire putative hydrophobin gene family. One spore hydrophobin, HfbA, shared 72.56% sequence identity to the Aspergillus fumigatus spore hydrophobin RodA and was required for efficient spore dispersion in The Δ mutant was likewise reduced in spore dispersal, hypothesized to be due to the aberrant shape and clumping of the Δ conidia and conidiophores. Additionally, the Δ mutant presented several differences in physiological traits, including decreased survival in extreme cold temperatures and increased production of several toxic secondary metabolites. Most striking was the unexpected fitness advantage that the Δ strain displayed in competitive passaging with the wild-type strain on host apple where the mutant significantly increased in percentage of the colonizing population. This work uncovers potential ecological trade-offs of hydrophobin presence in filamentous fungi. Hydrophobins are amphipathic secreted proteins uniquely found in filamentous fungi. These proteins self-assemble and constitute the outer most layer of fungal surfaces thus mediating multiple aspects of fungal interactions with their environments. Hydrophobins facilitate spore dispersal, yet a full understanding of the function and need for multiple hydrophobins in fungal species remains elusive. To address the role of this protein family in , the causative agent of blue mold disease in pome fruit, all seven putative hydrophobin genes were deleted and the mutant assessed for numerous physiological traits and virulence on fruit. Despite showing a decrease in spore dispersal, the septuple-deletion mutant was more fit than the wild type in competitive pathogenicity tests on apple. Our findings suggest this gene family illustrates a functional trade-off between dispersal and host colonization in .
水蛋白是仅存在于真菌中的小两亲性表面蛋白。在丝状子囊菌中，一组水蛋白的保守作用是它们对孢子扩散的需求。这些蛋白质对真菌生物学的其他贡献则不太清楚，并且因属而异。为了确定这些蛋白在真菌生物学和毒力中的功能，我们创建了七个单突变体和一个整个假定水蛋白基因家族的七倍缺失突变体（Δ）。一个孢子水蛋白 HfbA 与烟曲霉孢子水蛋白 RodA 有 72.56%的序列同一性，是高效孢子分散所必需的 在Δ突变体中，孢子分散同样减少，据推测是由于Δ分生孢子和分生孢子梗的形状异常和团聚。此外，Δ突变体在生理特征上表现出几种差异，包括在极端低温下的存活率降低和几种毒性次生代谢物的产量增加。最引人注目的是Δ菌株在与野生型菌株在宿主苹果上进行竞争传代时表现出的意外适应优势，在这种情况下，突变体在定植种群中的百分比显著增加。这项工作揭示了水蛋白在丝状真菌中存在的潜在生态权衡。 水蛋白是一种独特存在于丝状真菌中的两亲性分泌蛋白。这些蛋白自我组装并构成真菌表面的最外层，从而介导真菌与环境相互作用的多个方面。水蛋白促进孢子扩散，但对真菌物种中多种水蛋白的功能和需求仍不完全了解。为了解决这种蛋白家族在 中的作用，该蛋白是苹果果实青霉病的病原体，我们删除了所有七个假定的水蛋白基因，并评估了突变体在果实上的许多生理特征和毒力。尽管显示出孢子分散减少，但在苹果上的竞争性致病性测试中，七倍缺失突变体比野生型更适应。我们的发现表明，这个基因家族在 中展示了在扩散和宿主定植之间的功能权衡。
