Penicillium oxalicum S-adenosylmethionine synthetase is essential for the viability of fungal cells and the expression of genes encoding cellulolytic enzymes

Characterization of the Gene Encoding S-adenosyl-L-methionine (AdoMet) Synthetase in Penicillium chrysogenum; Role in Secondary Metabolism and Penicillin Production

“…Previous results confirmed that the gene encoding AdoMet synthetase in A. nidulans (AnsasA) is essential and its functions are indispensable for the cellular activities of this filamentous fungus [28]. Similar conclusions were raised in P. oxalicum [29]. Our initial attempts to obtain knockout mutants in the Pc16g04380 gene were unsuccessful, which is consistent with the fact that this is gene encoding AdoMet synthetase (PcsasA) is essential for the viability of P. chrysogenum too.…”

“…Interestingly, reduced levels of AdoMet also produced accumulation of a yellow-orange pigment. A similar effect was observed in P. oxalicum, where downregulated PosasA expression led to the formation of pink colonies instead of the dark-green colonies of the wild-type strain, which was attributed to the impairment of formation of melanins [29]. P. chrysogenum is able to synthesize several yellow pigments, such as chrysogine (chrysogenine) [48] and sorbicillinoids [49].…”

“…PcsasA is present as a single copy in the P. chrysogenum genome, thus giving rise to only one form of the protein. The presence of a single AdoMet synthetase gene has also been reported in P. oxalicum and A. nidulans [28,29]. With the only exceptions of Aspergillus flavus and Aspergillus oryzae, which contain two independent isoforms of AdoMet synthetase, all Aspergillus species contain only one AdoMet synthetase encoding gene [28].…”

“…In silico analysis of the P. chrysogenum Wisconsin 54-1255 genome [42] revealed the presence of a single 1317-bp gene (Pc16g04380), whose cDNA (1164 bp) encodes a putative protein of 387 amino acids and a predicted molecular mass of 42.18 kDa (isoelectric point 5.66). The predicted amino acid sequence of this protein showed high similarity with wellcharacterized AdoMet synthetases from other eukaryotes, such as the trypanosomatid Leishmania infantum [21] (61% identity) or Homo sapiens [43] (68% identity), and with other filamentous fungi, such as AN1222 from A. nidulans [28] (90% identity) or PDE_07230 from P. oxalicum [29]. This protein contains the conserved motifs of AdoMet synthetases, namely the hexapeptide GAGDQG (responsible for binding adenine moiety of ATP) [44] between residues 123-128, and the glycine-rich nonapeptide GGGAFSGKD that has been proposed to bind the triphosphate moiety of ATP [45] between residues 270-278.…”

“…In the second article, AdoMet synthetase of Aspergillus nidulans (AnSasA) was reported to regulate sporogenesis and the production of secondary metabolites [28]. Finally, and very recently, it was confirmed that in Penicillium oxalicum AdoMet synthetase (PoSasA) is essential for viability and for the expression of extracellular glycoside hydrolases (specifically cellulolytic enzymes) encoding genes [29]. Therefore, more information about AdoMet synthetases is necessary to determine the role of this enzyme and its product in filamentous fungi.…”