Aspergillus Unit, Institut Pasteur, Paris, France.
Université Paris Diderot, Sorbonne Paris Cité, Paris, France.
Cell Microbiol. 2019 Dec;21(12):e13102. doi: 10.1111/cmi.13102. Epub 2019 Aug 30.
The cell wall of Aspergillus fumigatus is predominantly composed of polysaccharides. The central fibrillar core of the cell wall is composed of a branched β(1-3)glucan, to which the chitin and the galactomannan are covalently bound. Softening of the cell wall is an essential event during fungal morphogenesis, wherein rigid cell wall structures are cleaved by glycosyl hydrolases. In this study, we characterised the role of the glycosyl hydrolase GH55 members in A. fumigatus fungal morphogenesis. We showed that deletion of the six genes of the GH55 family stopped conidial cell wall maturation at the beginning of the development process, leading to abrogation of conidial separation: the shape of conidia became ovoid, and germination was delayed. In conclusion, the reorganisation and structuring of the conidial cell wall mediated by members of the GH55 family is essential for their maturation, normal dissemination, and germination.
烟曲霉细胞壁主要由多糖组成。细胞壁的中心纤维核心由支链β(1-3)葡聚糖组成，几丁质和半乳甘露聚糖通过共价键与之结合。细胞壁软化是真菌形态发生过程中的一个重要事件，在此过程中，糖苷水解酶会切割刚性细胞壁结构。在这项研究中，我们研究了糖苷水解酶 GH55 成员在烟曲霉真菌形态发生中的作用。我们发现，GH55 家族的六个基因缺失阻止了分生孢子细胞壁在发育过程早期的成熟，导致分生孢子分离中断：分生孢子的形状变成了椭圆形，萌发被延迟。总之，GH55 家族成员介导的分生孢子细胞壁的重组和结构对于其成熟、正常传播和萌发是必不可少的。
