Project description:To investigate the molecular mechanism underlying the effect of sinapic acid on the decolorization of Ponceau 2R by T. hirsuta X-13, comparative transcriptomic analyses were conducted across four groups: the strain cultured on basic medium (CK), basic medium containing Ponceau 2R (P2R), basic medium containing sinapic acid (SA), and basic medium containing both Ponceau 2R and sinapic acid (P2R+SA).
Project description:BackgroundFungi are organisms with the highest natural capacity to degrade lignocellulose substrates, which is enabled by complex systems of extracellular enzymes, whose expression and secretion depend on the characteristics of substrates and the environment.ResultsThis study reports a secretome analysis for white-rot basidiomycete Trametes hirsuta cultivated on a synthetic media and a lignocellulose substrate. We demonstrate that T. hirsuta st. 072 produces multiple extracellular ligninolytic, cellulolytic, hemicellulolytic, peroxide generating, and proteolytic enzymes, as well as cerato-platanins. In contrast to other white rot species described earlier, which mostly secreted glucanases and mannosidases in response to the presence of the lignocellulose substrate, T. hirsuta expressed a spectrum of extracellular cellulolytic enzymes containing predominantly cellobiases and xylanases. As proteomic analysis could not detect lignin peroxidase (LiP) among the secreted lignin degrading enzymes, we attributed the observed extracellular LiP - like activity to the expressed versatile peroxidase (VP). An accessory enzyme, glyoxal oxidase, was found among the proteins secreted in the media during submerged cultivation of T. hirsuta both in the presence and in the absence of copper. However, aryl-alcohol oxidase (AAO) was not identified, despite the presence of AAO enzymatic activity secreted by the fungus. The spectra of the expressed enzymes dramatically changed depending on the growth conditions. Transfer from submerged cultivation to surface cultivation with the lignocellulose substrate switched off expression of exo-β-1,3-glucanase and α-amylase and turned on secretion of endo-β-1,3-glucanase and a range of glycosidases. In addition, an aspartic peptidase started being expressed instead of family S53 protease. For the first time, we report production of cerato-platanin proteins by Trametes species. The secretion of cerato-platanins was observed only in response to contact with lignocellulose, thus indicating a specific role of these proteins in degradation of the lignocellulose substrates.ConclusionsOur results suggest a sequential mechanism of natural substrate degradation by T. hirsuta, in which the fungus produces different sets of enzymes to digest all main components of the substrate during cultivation.
Project description:Trametes hirsuta AH28-2 is a white-rot basidiomycete originally isolated from rotting wood in China. This strain can secrete high levels of extracellular laccase induced by copper and o-toluidine with great potential applications in industry and environment. However, the proteomics and mechanisms for regulating laccases from T. hirsuta AH28-2 fungi at the protein level have not been investigated. To explore the functional factors related to laccases, label-free quantification proteomics was used to identify proteins produced by T. hirsuta AH28-2, and the differentially expressed proteins (DEPs) were compared in the control, 2 mM o-toluidine and 50 uM copper ion cultures of T. hirsuta AH28-2 for 48h. Here, across all samples, a total of 5,089 proteins were quantified, of which 504 exhibited significant differential expression (278 up-regulated and 226 down-regulated) in the o-toluidine induction group, and 447 with significant differential expression (282 up-regulated and 165 down-regulated) in the copper induction group. These DEPs from o-toluidine induction group were significantly enriched in the pathways of sphingolipid metabolism, toluene degradation, DNA replication and drug metabolism-cytochrome P450, and DEPs from copper induction group were significantly enriched in aminobenzoate degradation and ABC transporters pathways. Furthermore, a total of 120 and 119 DEPs identified in o-toluidine- and copper- induction group were predicted as TFs, respectively. Protein-protein interaction networks analyses showed that Zn2Cys6 (GME7257_g and GME6689_g) transcription factors possessed strong protein interaction with laccases in o-toluidine- and copper-induction group. Several proteins with different expression were consistent with the proteomics of T. hirsuta AH28-2 by parallel reaction monitoring (PRM) verification.