Fungal pathogens affect a wide variety of hosts, such as human beings, plants, animals,
and insects. The course of infection relies on the virulence grade of the fungus and the strength of the
defense mechanisms of the host. Virulence factors are closely related to the cell surface; cell wall proteins
have a crucial role in adhesion, hyphal development, hydrophobicity, biofilm formation, immunomodulation
and surface variation. The enzymes involved in cell wall biosynthesis are not proper
virulence factors, but they are necessary for cell function. The deletion of the genes encoding those
enzymes often results in an attenuation of virulence. Secreted proteins and cell wall proteins are
modified with sugar residues through the N- and O- glycosylation pathways. A set of glycosidases
and glycosyltransferases from the Endoplasmic Reticulum and Golgi bodies determine the outcome
of the protein. Proper protein glycosylation is important for folding, localization and protein function.
In fungi, the glycoproteins are particularly enriched with mannose moieties. In this review, the role of
mannosyltransferases from the Pmt, Ktr/Mnt, Mnn and Och1families for the full development of fungal
virulence is summarized and discussed.