Intra- and Interspecies Virus Transfer in Aspergilli via Protoplast Fusion

Mycoviruses: future therapeutic agents of invasive fungal infections in humans?

“…A complete list of mycoviruses of plant pathogenic fungi can be found in a recent review by Pearson et al [4]. Despite the limited data on mycoviruses of human pathogenic fungi, evidence is provided that mycoviruses do exist in various fungal genera that are pathogenic to humans [6][7][8][9][10][11][12][13][14][15][16][17][18]. The mycoviruses that are associated with fungal genera that can cause human fungal disease and are also formally known by the ICTV are listed in Table 1.…”

“…Transmission also occurs horizontally via cytoplasmic exchange during cell division and mating with strains that, depending on the genus, do not have to be genetically compatible for virus transfer to occur [9,[19][20][21][22]. As a rule, however, when two fusing hyphae are not compatible, they recognize each other as nonself, which triggers programmed cell death (PCD).…”

“…2). Rejection of heterokaryon formation has been observed to be relatively mild or absent when hyphae of less related Aspergillus species fuse [9].…”

“…Using protoplast fusion, mycoviruses may even be transferred between two fungal compartments of strains that are heterokaryon incompatible [9].…”

“…Co-infections may be generated, but the mycovirus in the acceptor fungus may also be replaced by the mycovirus from the donor. Indeed, viruses are not always detected in the colonies derived from the protoplast/ hyphae fusion products [9]. This suggests that mycoviruses can be selectively eliminated upon regeneration and outgrowth of (transfected) protoplasts as a result of intrahost competition between viruses.…”