SWATH label-free proteomics analyses revealed the roles of oxidative stress and antioxidant defensing system in sclerotia formation of Polyporus umbellatus

Abstract

Understanding the initiation and maturing mechanisms is important for rational manipulating sclerotia differentiation and growth from hypha of Polyporus umbellatus. Proteomes in P. umbellatus sclerotia and hyphae at initial, developmental and mature phases were studied. 1391 proteins were identified by nano-liquid chromatograph-mass spectrometry (LC-MS) in Data Dependant Acquisition mode, and 1234 proteins were quantified successfully by Sequential Window Acquisition of all THeoretical fragment ion spectra-MS (SWATH-MS) technology. There were 347 differentially expressed proteins (DEPs) in sclerotia at initial phase compared with those in hypha, and the DEP profiles were dynamically changing with sclerotia growth. Oxidative stress (OS) in sclerotia at initial phase was indicated by the repressed proteins of respiratory chain, tricarboxylic acid cycle and the activation of glycolysis/gluconeogenesis pathways were determined based on DEPs. The impact of glycolysis/gluconeogenesis on sclerotium induction was further verified by glycerol addition assays, in which 5% glycerol significantly increased sclerotial differentiation rate and biomass. It can be speculated that OS played essential roles in triggering sclerotia differentiation from hypha of P. umbellatus, whereas antioxidant activity associated with glycolysis is critical for sclerotia growth. These findings reveal a mechanism for sclerotial differentiation in P. umbellatus, which may also be applicable for other fungi.

Cell Wall Strengthening and Remodeling Provide New Insights on Sclerotia Development of Medicinal Fungus Polyporus Umbellatus

“…Differentially expressed proteins contribute to thickened cell wall of sclerotia Proteins in initial sclerotia (IS), development sclerotia (DS) and mature sclerotia (MS) were identi ed by our previous work, so did DEPs of DS vs. IS, MS vs. DS and MS vs. IS 4 . 611 merged DEPs were obtained among the DS vs. IS, MS vs. DS and MS vs. IS groups (as shown in Supplementary Table S1) including 85 unknown proteins (comp11158_c0, comp13970_c0, comp142821_c0, etc) and 526 identi ed proteins (Q49W60, O14241 and Q1K9C2 etc.)…”

“…In fact, the medicinal parts of P. umbellatus displayed these bioactivities are a specialized structure named sclerotia which differentiated from hypha 4 . The sclerotium is a structure that supports long-term survival and is intricately linked with structural changes to the thick-walled cell [5][6] induced adverse environmental conditions 7,8 .…”

“…Initial sclerotia (IS) differentiated from hypha and then developed to development sclerotia (DS) and mature sclerotia (MS) 4 . In the current study we obtained biomarkers at the protein level contributing to thickened cell wall in sclerotia and how they aide regulation of cell wall strengthening and remodeling of P. umbellatus.…”

Large Scale Proteomic Data and Network-Based Systems Biology Approaches to Explore the Plant World

“…However, the integration of complementary approaches and data is mandatory to improve the quality of plant research, and despite all the limitations related to plant organisms, the results reported in the proteomic studies mentioned here are promising and they are attracting the interest of a growing number of plant biologists. In fact, different examples demonstrated the power of high-throughput proteomic technologies to address plant biology questions by characterizing thousands of proteins per sample and multiple biomarkers [ 23 , 25 , 26 , 27 , 28 , 29 , 30 ].…”

“…On the contrary, fewer studies relied on the combination of high-throughput proteomic data and protein-protein interaction (PPI) network models [ 20 , 21 , 22 ]. However, in the last few years an increasing number of authors focused their activity on the high-throughput profiling of plant proteomes [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ] as well as on the experimental [ 31 , 32 , 33 ] and computational detection of PPIs [ 34 , 35 , 36 , 37 ].…”