Editorial: Molecular Mechanisms Underlying Polyamine Functions in Plants

Polyamines are small organic bases that have been found in all living organisms where they play important roles in the regulation of growth, development and responses to biotic and abiotic stimuli. They do so by modulating a variety of cellular processes such as cell division, expansion, differentiation, death, nucleic acids, and protein synthesis and function. This diversity of functions derives in part from the ability of polyamines to interact with negatively charged sites in molecules such as nucleic acids, proteins, and lipids. It also derives from their ability to conjugate with a variety of macromolecules such as phenolic compounds and proteins. Furthermore, some products of polyamine catabolism have been found to play critical signaling roles in a variety of physiological, cellular, and developmental processes. In plants, polyamines have also been found to regulate growth, development, and responses to biotic and abiotic cues. Therefore, it is no surprise that recent attempts at manipulating the signaling pathways leading to polyamines metabolism and/or function have been successful at improving plant growth, affecting development and/or improving tolerance to environmental stress (Alcázar and Tiburcio, 2014). Yet, despite an abundance of recent research publications discussing polyamines metabolism and function in plants, much remains to be elucidated to allow the development of better strategies aimed at designing plants with improved tolerance to the stresses associated with global warming, generating crops with more effective growth in marginal lands to allow food, feed, and fiber production for a rapidly expanding world population, and increasing the production of biomass with improved characteristics for biofuel production. This research topic aims at highlighting recent advances in plant polyamine research. We collected 14 manuscripts focusing on the metabolism of polyamines and the roles they play in the regulation of plant growth, development, environmental stress response, and stress mitigation. By inviting authors with a broad range of expertise and demonstrated contributions to the field, we aimed at promoting interactions between research teams, reviewers and editors, and linking together different disciplines to resolve longstanding questions related to polyamines metabolism and function in plants. Two groups of important polyamines have been found to play important roles in the regulation of plant growth, development, and environmental responses: (1) the better characterized putrescine and its derived polyamines, and (2) the less-characterized cadaverine. Most of the papers included in this topic describe research aimed at characterizing the metabolism of, and functions associated with the first group of compounds.