The relative expression of the 12 genes in stages PF-2341066 that precede fructification helped elucidate the correlation

between nutrient depletion and fructification (Figure 6) since the genes MpRHEB, MpRHO1-GEF, MpADE, MpMBF, and MpRAB putatively involved in signaling are associated with internal perception of the signals triggered by nutrient depletion and other stresses, which was noticeable before the primordia appeared. The putative gene MpRHEB is associated with growth regulation probably during nitrogen depletion [54]. Its expression in M. perniciosa increased in reddish pink mycelium, immediately before stress and continued at a high level until the beginning of the primordial and basidiomata phases (Figure 6D). The expression of the high-affinity transporter MpGLU [51] peaked in this mycelium before stress (Figure 6E), strongly indicating a nutritional deficit, namely low external find more glucose concentration. Moreover, expression of MpCPR and MpCYP was low during this period (Figure 6G and 6K), indicating a lower basal metabolism [48]. The expression of MpRAB (Figure 6J) may indicate nutrient remobilization, since it BAY 57-1293 is involved in intracellular traffic [55, 56]. During the water stress applied to trigger in vitro fructification expression of some genes peaked. Transcripts

of putative MpMBF (multi-protein-bridging factor), a co-activator related to tolerance to abiotic stresses in plants [57], increased 2.4-fold (Figure 6I). Other genes with increased expression during this stress period were MpRHO1-GEF (Figure 6H), involved in signaling for the regulation of polarized growth [58] and MpRPL18 (Figure 6L) involved in protein synthesis. Involvement of signalization, probably cAMP-mediated, is likely due the expression of adenylate

cyclase that decreased in the yellow and reddish-pink mycelial phases, to return to the original levels observed on white mycelium just after the stress period (Figure 6F). As adenylate cyclase is subject to post-translational regulation, studies of enzymatic activity would be necessary to confirm this hypothesis. The gene p-rho/gef is, therefore, possibly correlated with cAMP Cytidine deaminase pathways. Repression of the glucose transporter coincided with the repression of the adenylate cyclase gene, which also indicates cAMP signaling. In S. pombe the glucose levels are regulated by adenylate cyclase [59] and in Sclerotinia sclerotiorus the development of reproductive structures is negatively regulated by cAMP [60] Putative aegerolysins and pleurotolysin B of M. perniciosa are differentially expressed during fructification As described for other fungi, probable hemolysins are highly expressed at the fructification stages [47, 61]. We identified three putative genes involved in fructification, two more closely related to the identified AA-Pri1 or PriAs of Agrocybe aerogerita and P. ostreatus, respectively, and one more closely related to pleurotolysin B, also identified in P. ostreatus.