Chitin deacetylases Cod4 and Cod7 are involved in polar growth of Aspergillus fumigatus

摘要

Chitin is one of the key components of fungal cell wall, and chitin deacetylases (CDAs) have been found in fungi; however, their functions remain unknown. is known to cause fatal invasive aspergillosis (IA) among immunocompromised patients with a high mortality rate. Although the cell wall has long been taken as a unique target for drug development, its dynamic remodeling is complicated and not well understood. Seven putative CDAs are annotated in the genome. In this study, we analyzed the function of the putative CDAs, Cod4 and Cod7, in . Biochemical analysis of recombinant proteins showed that Cod4 preferentially deacetylated (GlcNAc) and was less active on chitooligosaccharides with DP > 5, whereas Cod7 was unable to catalyze deacetylation. Simulation of three‐dimensional structure revealed that both Cod4 and Cod7 shared a similar folding pattern with PgdA from and, similar to PgdA, a substitution of Thr8 by Ala8 in Cod7 abolished its CDA activity. Deletion of the , , or both in led to polarity abnormality and increased conidiation. Furthermore, the expression level of the genes related to polarity was upregulated in the mutants. Our results demonstrated that Cod4 and Cod7 were involved in polarity, though Cod4 was inactive.