ITRAQ-based quantitative proteomic analysis of mycelium in different predation periods in nematode trapping fungus Duddingtonia flagrans

Abstract

Duddingtonia flagrans, as a representative species of nematode-trapping fungi, has a strong environmental tolerance and nematode-trapping ability and is thought of as the most promising candidate for use as a biological agent. To clarify the proteomic differences during different predation periods and to explore the molecular background of the nematode-trapping mechanism, we carried out an iTRAQ (isobaric tags for relative and absolute quantitation)-based quantitative proteomic analysis for Duddingtonia flagrans during three predatory stages (0 h, 12 h, and 48 h). A total of 4244 proteins were detected; 474 of these showed differential protein abundance from 0 h to 12 h, while 119 showed differential protein abundance from 12 h to 48 h. The 474 proteins from 0 h to 12 h were primarily associated with catalytic activity, molecular binding function, transport activity, biological regulation, stress response, biolocation and carbon utilization, while the 119 proteins from 12 h to 48 h were involved in substance and energy metabolism. Further bioinformatics analysis showed that these proteins could be mapped to various pathways, eight of which were significantly enriched after mapping to KEGG pathways from 0 h to 12 h, and substance and energy metabolism were enriched from 12 h to 48 h. Interestingly, many of these differentially expressed proteins were involved in the significantly enriched pathways of ubiquitin-mediated proteolysis, endoplasmic reticulum protein processing, sphingolipid metabolism, adhesion processes, MAPK signaling pathway, AMPK signaling pathway, energy and carbon metabolism, peroxidase, and oxidative phosphorylation, including acid phosphatase, neutral ceramidase, sphingomyelin phosphodiesterase, tyrosinase, and serine protease. These findings not only deepen our understanding of the proteome during different predation periods in Duddingtonia flagrans but also provide a basis for screening and identification of predation-related proteins to reveal the biological processes of the fungus and its action on nematodes, thereby helping to elucidate the nematode-trapping mechanism of D. flagrans.