Cytological and proteomic analyses of horsetail (Equisetum arvense L.) spore germination

Abstract

Spermatophyte pollen tubes and root hairs have been used as single-cell-type model systems to understand the molecular processes underlying polar growth of plant cells. Horsetail (Equisetum arvense L.) is a perennial herb species in Equisetopsida, which creates separately growing spring and summer stems in its life cycle. The mature chlorophyllous spores produced from spring stems can germinate without dormancy. Here we report the cellular features and protein expression patterns in five stages of horsetail spore germination (mature spores, rehydrated spores, double-celled spores, germinated spores, and spores with protonemal cells). Using 2-DE combined with mass spectrometry, 80 proteins were found to be abundance changed upon spore germination. Among them, proteins involved in photosynthesis, protein turnover, and energy supply were over-represented. Thirteen proteins appeared as proteoforms on the gels, indicating the potential importance of post-translational modification. In addition, the dynamic changes of ascorbate peroxidase, peroxiredoxin, and dehydroascorbate reductase implied that reactive oxygen species homeostasis is critical in regulating cell division and tip-growth. The time course of germination and diverse expression patterns of proteins in photosynthesis, energy supply, lipid and amino acid metabolism indicated that heterotrophic and autotrophic metabolism were necessary in light-dependent germination of the spores. Twenty-six proteins were involved in protein synthesis, folding, and degradation, indicating that protein turnover is vital to spore germination and rhizoid tip-growth. Furthermore, the altered abundance of 14-3-3 protein, small G protein Ran, actin, and caffeoyl-CoA O-methyltransferase revealed that signaling transduction, vesicle trafficking, cytoskeleton dynamics, and cell wall modulation were critical to cell division and polar growth. These findings lay a foundation toward understanding the molecular mechanisms underlying fern spore asymmetric division and rhizoid polar growth.

Comparative Proteomic Analysis of Soybean Leaves and Roots by iTRAQ Provides Insights into Response Mechanisms to Short-Term Salt Stress

“…To predict the relationship among all these identified DEPs in soybean leaves and roots, a protein-protein interaction (PPI) networks were generated using the web-tool STRING 9.1. A total of 104 differentially abundant proteins represented by 72 unique proteins from soybean were shown in the PPI network (Figure 5 , Table S6 ) based on the published literature and other experimental evidence (Zhao et al, 2015 ). Four functional modules forming tightly-connected clusters were illuminated in the network (Figure 5 ).…”

Genome-wide identification, molecular evolution, and expression analysis of auxin response factor (ARF) gene family in Brachypodium distachyon L

“…Brachypodium distachyon L . , a model plant for economically important crop species including wheat and barley was selected as organism, and the PPI network with a confidence score of at least 0.700 was constructed [ 97 , 98 ] and displayed using Cytoscape (version 3.0.2) software [ 99 ].…”

Distinct metabolic changes between wheat embryo and endosperm during grain development revealed by 2D‐DIGE‐based integrative proteome analysis

“…The KOG numbers of DEP spots were matched in the EggNOG database (version 4.0, http://eggnogdb.embl.de/#/app/home) . The analysis of protein‐protein interaction (PPI) was obtained by using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database (version 9.1, http://string-db.org) , and the PPI network with a confidence score of at least 0.700 was constructed , and displayed using Cytoscape (version 3.0.2) software . Subcellular locations of identified proteins were predicted using WoLF PSORT (http://wolfpsort.org/) , Predotar (http://urgi.versailles.inra.fr/predotar/predotar.html) and UniprotKB (http://www.uniprot.org/) database programs.…”