iTRAQ-MS/MS Proteomic Analysis Reveals Differentially Expressed Proteins During Post-harvest Maturation of the White Button Mushroom Agaricus bisporus

Agaricus bisporus (J. E. Lange) Imbach, well known as the common cultivated mushroom or white button mushroom, is widely cultivated all over the world. We used iTRAQ-MS/MS (i.e., isobaric tags for relative and absolute quantification-coupled two-dimensional liquid chromatography-tandem mass spectrometry) to identify protein expression changes that occur during the post-harvest maturation of Agaricus bisporus fruitbodies at 0, 6, 12, and 48 h after harvest. A total of 5878 unique peptides, representing 1063 proteins, were identified. Quantitative data were obtained from 1012 out of the 1063 proteins. A total of 102, 106, and 160 differentially expressed proteins (> twofolds differences) were identified from samples collected at 6, 12, and 48 h compared to sample from 0 h post harvest, accounting for 10.1, 10.5, and 15.8% of the total proteins identified, respectively. All identified proteins including the differentially expressed proteins among different post-harvest stages were subjected to bioinformatic analysis. Furthermore, seven representative proteins either up or down-regulated at different post-harvest stages were analyzed by real-time PCR. Three out of the seven proteins, the mismatched base pair and cruciform DNA recognition protein, hydrophobin-B and protein transporter, exhibited similar expression patterns as their corresponding proteins. The 260 differentially expressed proteins identified from our study laid a foundation for future studies aiming to understand the post-harvest maturation process of A. bisporus and eventually, might help in the development of breeding program to identify strains with extended shelf life.