Conservation of Thermospermine Synthase Activity in Vascular and Non-vascular Plants

Abstract

In plants, the only confirmed function for thermospermine is regulating xylem cells maturation. However, genes putatively encoding thermospermine synthases have been identified in the genomes of both vascular and non-vascular plants. Here, we verify the activity of the thermospermine synthase genes and the presence of thermospermine in vascular and non-vascular land plants as well as in the aquatic plant Chlamydomonas reinhardtii . In addition, we provide information about differential content of thermospermine in diverse organs at different developmental stages in some vascular species that suggest that, although the major role of thermospermine in vascular plants is likely to be xylem development, other potential roles in development and/or responses to stress conditions could be associated to such polyamine. In summary, our results in vascular and non-vascular species indicate that the capacity to synthesize thermospermine is conserved throughout the entire plant kingdom.

Thermospermine Synthase (ACL5) and Diamine Oxidase (DAO) Expression Is Needed for Zygotic Embryogenesis and Vascular Development in Scots Pine

“…T-Spm has been identified as a plant growth regulator that represses xylem differentiation and promotes stem elongation by preventing premature death of developing xylem vessel elements in Arabidopsis (Kakehi et al, 2008;Muñiz et al, 2008;Vera-Sirera et al, 2010). However, ACL5 expression and the presence of T-Spm were recently found in non-vascular land plants and in the unicellular green alga Chlamydomonas reinhardtii (Solé-Gil et al, 2019), which suggested that T-Spm plays also other roles in addition to xylem development in vascular plants. Our present results show a novel function for ACL5 in the morphologically necrotic cell death and support the view of the genetic regulation of necrosis in Scots pine embryogenesis and further in plant development.…”

Current status and perspectives on the role of polyamines in plant immunity

“…SAMDC activity, has been detected in different compartments after subcellular fractionation in different plant species (Bagni & Tassoni, 2001; Kumar, Taylor, Altabella, & Tiburcio, 1997), but in silico analysis of A. thaliana SAMDC sequences suggests nuclear and cytosolic locations for this enzyme (B. Belda‐Palazón, personal communication), a view supported by experimental evidences obtained with other plant species (Liu et al, 2014). In addition to the ‘usual’ PAs, a wide range of vascular and non‐vascular plants also synthesise thermospermine (tSpm) (Solé‐Gil, Hernández‐García, López‐Gresa, Blázquez, & Agustí, 2019), a structural isomer of Spm produced by the thermospermine synthase ACL5 (EC 2.5.1.79). This tetraamine is involved in xylem differentiation (Muñiz et al, 2008), but might also have other roles (Solé‐Gil et al, 2019).…”

“…In addition to the ‘usual’ PAs, a wide range of vascular and non‐vascular plants also synthesise thermospermine (tSpm) (Solé‐Gil, Hernández‐García, López‐Gresa, Blázquez, & Agustí, 2019), a structural isomer of Spm produced by the thermospermine synthase ACL5 (EC 2.5.1.79). This tetraamine is involved in xylem differentiation (Muñiz et al, 2008), but might also have other roles (Solé‐Gil et al, 2019).…”

The tree of life of polyamine oxidases

“…Phylogenetic studies have suggested that the SPDS genes of the various organisms derive from a common ancestor preceding the separation between prokaryotes and eukaryotes and that they have been the origin of SPMS and TSPMS activities through gene duplication and/or neofunctionalization 16 . Moreover, it has been hypothesized that plants acquired TSPMS early during evolution by horizontal gene transfer from archaea or bacteria 16 – 18 .…”

“…While several studies have been performed on the evolutionary pathways of genes involved in polyamine biosynthesis 10 , 11 , 16 – 18 , 48 , comparatively less is known about the evolutionary history of genes involved in polyamine catabolism. Most studies have focused on the genomic identification and biochemical characterization of PAO isoforms from single species and therefore they used phylogenetic methods mainly for delimiting clusters and subfamilies to which to assign PAO isoforms 49 – 51 .…”