# Towards Understanding the Function of Aegerolysins
## 2 Aegerolysins
### Fungal Aegerolysins from Basidiomycota--Agaricomycotina
#### 2.1.4 Aegerolysins from _Moniliophthora_ _perniciosa_  
The species complex _Moniliophthora_ _perniciosa_ ([PERSON] and [PERSON] (2005) (_Crinipellis_ _perniciosa_) (_Agaricales_) consists of a number of geographically separated populations that infect a broad range of different hosts: biotype C on _Thebroma_ and _Herrania_ spp. (_Malvacaee_), H on _Heteropterys acutifola_ (_Malpighiaceaee_), L _Arrabidaea_ spp. (_Bignoniaceaee_), and S on _Solanum_ spp. (_Solanaceaee_) [18]. It is most known as a hemibiotrophic fungus that causes witches' broom disease in cacao plant (_Thebroma cacao_ L.) with two distinct growth phases [18].  
The ability to culture a biotrophic-like phase of _M. perniciosa_ in vitro, as well as the recent findings from the nearly complete genome and expression studies, clearly indicate that these different growth phases of the fungus function under different metabolic parameters [18]. The gene expression profile determined by microarray suggests physiological changes in the mycelia prior to basidiomata formation, and confirmed by RT-qPCR at different stages during cultivation in basidiomata-inducing medium [101]. Of the three putative genes involved in fructification, two are related to the identified **PriA** from _P. ostreatus_ and **AA-Pri1** from _A. aegerita_, respectively, and one is related to **PlyB** from _P. ostreatus_. The expression of aegerolysin **MpPRIA1** was low in yellow and reddish-pink mycelial stages and before stress, but increased about fourfold in mycelia with primordia and 90-fold in basidiomata compared to the initial white mycelial stage [101]. Expression of the aegerolysin **MpPRIA2** increased 17-fold at the reddish-pink mycelium stage, but decreased 11-fold before stress, 4-fold in stressed mycelia, and 47-fold in mycelia with primordia. Transcripts of the gene **MpPRIA2** increased 23-fold in basidiomata, which was lower in mycelia with primordia [101]. Transcripts of the gene **MpPLYB** increased 1.4-fold in the yellow mycelium stage, 15-fold in reddish-pink mycelia, and remained at high levels in mycelia before stress, under stress, and in mycelia with primordia (about 10-12-fold increase), but decreased in basidiomata, where they were only 1.6-fold higher than in white mycelia [101]. **MpPRIA1** and **MpPRIA2** have homologous regions but appear to correspond to two individual genes whose expression is consistent with the morphological differentiation of primary hyphal nodules from primordia. These aegerolysins may contribute to the process of hyphal aggregation, as their expression, albeit at low levels, occurred prior to the appearance of primordia, when hyphae became spherical for primordia formation [102]. This stage coincides with the stage of reddish-pink mycelium, where hyphal nodules are detectable. The exact function of these proteins remains unclear, but their involvement in programmed cell death seems rather unlikely, since aegerolysins from _Pleurotus_ have a lytic function and act in SM/Chol membranes at pH between 7 and 8, which is not normally the case in fungal cells [65; 103; 104]. However, they can also act lytically on membranes composed of SM and ergosterol, although the binding and permeabilization is twice less efficient as for the SM/Chol membranes [69].  
Six aegerolysins are encoded in the _M. perniciosa_ genome according to Pf06355 search. The contigs are too short to detect whether the only homolog of **PlyB--MpPLYB** gene is a neighboring gene of **MpPRIA1** and **MpPRIA2** genes.