Protein O-mannosyltransferase 1 (AfPmt1p) in Aspergillus fumigatus is crucial for cell wall integrity and conidia morphology especially at an elevated temperature

State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.; The General Hospital of Chinese People's Armed Police Forces, Beijing, China.; Research Center for Medical Mycology, Peking University First Hospital, Peking University, Beijing 100034, China

^* To whom correspondence should be addressed. Email: jinc{at}sun.im.ac.cn.

	Abstract

Protein O-mannosyltransferases (PMTs) initiate O-mannosylation of secretory proteins, which are of fundamental importance in eukaryotes. In this study, the PMT gene family of the human fungal pathogen Aspergillus fumigatus was identified and characterized. Unlike Saccharomyces cerevisiae where the PMT family is highly redundant, only one member of each PMT subfamily is present in A. fumigatus, namely, afpmt1, afpmt2 and afpmt4. Deletion of the afpmt1 is viable. In vitro and in vivo activity assays confirmed that the protein encoded by the afpmt1 acts as O-mannosyltransferase (AfPmt1p). Characterization of the afpmt1 mutant showed that lack of AfPmt1p results in sensitivity to elevated temperature, defect in growth and cell wall integrity, thereby affecting cell morphology, conidia formation and germination. In a mouse model, the afpmt1 was not required for the virulence of A. fumigatus under the experimental conditions.