Cytological and Proteomic Analyses of Osmunda cinnamomea Germinating Spores Reveal Characteristics of Fern Spore Germination and Rhizoid Tip Growth*

Abstract

Fern spore is a good single-cell model for studying the sophisticated molecular networks in asymmetric cell division, differentiation, and polar growth. Osmunda cinnamomea L. var. asiatica is one of the oldest fern species with typical separate-growing trophophyll and sporophyll. The chlorophyllous spores generated from sporophyll can germinate without dormancy. In this study, the spore ultrastructure, antioxidant enzyme activities, as well as protein and gene expression patterns were analyzed in the course of spore germination at five typical stages (i.e. mature spores, rehydrated spores, double-celled spores, germinated spores, and spores with protonemal cells). Proteomic analysis revealed 113 differentially expressed proteins, which were mainly involved in photosynthesis, reserve mobilization, energy supplying, protein synthesis and turnover, reactive oxygen species scavenging, signaling, and cell structure modulation. The presence of multiple proteoforms of 25 differentially expressed proteins implies that post-translational modification may play important roles in spore germination. The dynamic patterns of proteins and their encoding genes exhibited specific characteristics in the processes of cell division and rhizoid tip growth, which include heterotrophic and autotrophic metabolisms, de novo protein synthesis and active protein turnover, reactive oxygen species and hormone (brassinosteroid and ethylene) signaling, and vesicle trafficking and cytoskeleton dynamic. In addition, the function skew of proteins in fern spores highlights the unique and common mechanisms when compared with evolutionarily divergent spermatophyte pollen. These findings provide an improved understanding of the typical single-celled asymmetric division and polar growth during fern spore germination. Molecular & Cellular

Na2CO3-Responsive Photosynthetic and ROS Scavenging Mechanisms in Chloroplasts of Alkaligrass Revealed by Phosphoproteomics

“…Chl contents were determined according to the method of Wang et al [69]. The ultrastructure of chloroplasts were observed under a JEOL-2000 transmission electron microscope (JEOL, Tokyo, Japan) according to Suo et al [72].…”

“…Total protein samples from leaves were prepared and analyzed using two-dimensional gel electrophoresis according to the method of Suo et al [72] and Dai et al [76]. The MS and MS/MS spectra were acquired on a MALDI-TOF/TOF mass spectrometer (AB Sciex Inc.) [69].…”

“…Functional domains of proteins were analyzed using BLAST programs (http://www.ncbi.nlm.nih.gov/BLAST/), and then were clustered by cluster 3.0 (http://bonsai.hgc.jp/~mdehoon/software/cluster/software.htm). The prediction of protein subcellular location was determined according to Suo et al [72]. The SWISS-MODEL comparative protein modeling server (http://swissmodel.expasy.org/) was employed to generate 3D structural models of phosphoproteins [83].…”

“…qRT-PCR amplification was performed using the specific primer pairs (Table S12) on a 7500 real time PCR system (Applied Biosystems Inc., USA). The amplification process was performed according the method of Suo et al [72].…”

Salinity-Induced Palmella Formation Mechanism in Halotolerant Algae Dunaliella salina Revealed by Quantitative Proteomics and Phosphoproteomics

“…The content of H 2 O 2 was measured by monitoring the A 410 of titanium-peroxide complex according to the method of Suo et al (2015). …”