Proteomics-based Mechanism Of Copper Resistance In High-resistance Copper Penicillium Janthinellum

The research on the mechanism of microorganisms' resistance to heavy metals is of great significance in theory,practical application,as well as the eukaryotes and human's health,and the bioremediation of heavy metal pollution.Copper(Cu)is a commonly used heavy metal element in life and industrial and agricultural production.It is both a trace element necessary for biological life activities and a heavy metal that is harmful to organisms at high concentrations.Filamentous fungi-copper(Cu)interactions are of great significance not only in natural and organisms-made ecosystems but also in bioremediation of heavy metal pollution.However many key issues still remain unclear at proteome levels.P.janthinellum strain(GXCR)is a highly resistant copper filamentous fungus obtained in our laboratory.Since the whole genome sequence was not completed and the genetic transformation system could not be established,it was difficult to study its anti-copper mechanism from the traditional perspective.So we try to open up new ideas from the perspective of science,especially proteomics.We compared six proteomes from Cu-resistant wild type(WT)Penicillium janthinellum strain GXCR and its Cu-sensitive mutant EC-6 under 0,0.5 and 3 mM Cu treatments using iTRAQ technique.A total of 495 known proteins were identified.Conclusions drawing from result analyses are:Cu tolerance depends on ATP generation and supply relevant to activities of pathways of glycolysis;OP,citrate cycle,gluconeogenesis,fatty acid synthesis and metabolism under Cu;high Cu sensitivity is mainly due to ATP energy deficit;among ATP generation pathways is there exist some Cu-sensitive and-insensitive metabolic steps;gluconeogenesis pathway is crucial to survival of the fungi in Cu-containing and sugar-scarce environments;the fungi follow two routes to change their proteomes to cope with changes in Cu concentrations:one is from ATP,ADRH,ribosome biogenesis to proteasome,and another from ATP,ADRH to spliceosome and/or stress adapted RNA degradosome;and there are unique routes to respond to high Cu.Further,general diagram of Cu-responsive paths and the model of high Cu sensitivity theory were proposed at proteome level.Our work not only provides the potential protein biomarkers indicating the Cu pollution,and target metabolic steps for engineering Cu tolerant fungi during bioremediation,but also presents clues for further insight into HM tolerance mechanisms of other eukaryotes.