A Decade of Pollen Phosphoproteomics

Abstract

Angiosperm mature pollen represents a quiescent stage with a desiccated cytoplasm surrounded by a tough cell wall, which is resistant to the suboptimal environmental conditions and carries the genetic information in an intact stage to the female gametophyte. Post pollination, pollen grains are rehydrated, activated, and a rapid pollen tube growth starts, which is accompanied by a notable metabolic activity, synthesis of novel proteins, and a mutual communication with female reproductive tissues. Several angiosperm species (Arabidopsis thaliana, tobacco, maize, and kiwifruit) were subjected to phosphoproteomic studies of their male gametophyte developmental stages, mostly mature pollen grains. The aim of this review is to compare the available phosphoproteomic studies and to highlight the common phosphoproteins and regulatory trends in the studied species. Moreover, the pollen phosphoproteome was compared with root hair phosphoproteome to pinpoint the common proteins taking part in their tip growth, which share the same cellular mechanisms.

MAPK20-mediated ATG6 phosphorylation is critical for pollen development in Solanum lycopersicum L.

“…In plants, MAPK cascades participate widely in signaling transduction during abiotic stresses, pathogens, and phytohormones [ 14 ]. In addition, more and more studies have shown that the MAPK signaling pathway mediates almost every stage of plant reproduction, such as gametogenesis, anther development, pollen development, ovule development, and pollen tube guidance [ 15 , 16 ]. In Arabidopsis mapk4 mutant plants, microsporoblasts fail to undergo meiotic cytokinesis, resulting in abnormal pollen grains [ 17 ].…”

“…In Arabidopsis, MAPK has been found to phosphorylate a variety of substrates, including transcription factors under different biological processes [ 13 , 16 , 23 ]. C-Jun N-terminal kinase, the homologous of MAPK in plants, is found to mediate the activation of autophagy in animal cells [ 48 ], but whether MAPK regulates autophagy in plants remains elusive.…”

Creation of a Plant Metabolite Spectral Library for Untargeted and Targeted Metabolomics

“…There are two major approaches for MS-based metabolomics: targeted and untargeted metabolomics [10]. Typically, the targeted metabolomics involved identifying and quantifying a group of known metabolites using selected reaction monitoring (SRM or SRMs when multiple transitions are monitored) with tandem mass spectrometers [11]. However, the targeted method is often limited to profiling the metabolites with available authentic standards.…”