Difference in Nitrogen Starvation-Inducible Expression Patterns among Phylogenetically Diverse Ammonium Transporter Genes in the Red Seaweed <i>Pyropia yezoensis</i>

Abstract

Nitrogen deficiency induces senescence and the expression of genes encoding ammonium transporters (AMTs) in terrestrial plants where the AMT family is subdivided into AMT1 and AMT2 subfamilies. Nitrogen starvation in the red seaweed Pyropia yezoensis causes senescence-like discoloration. In this study, we identified five genes in P. yezoensis encoding AMT domain-containing proteins, which were phylogenetically categorized into the AMT1 subfamily. We also found a gene encoding a Rhesus protein (Rh) that was related to, but diverged from, AMTs. Moreover, our phylogenetic analysis showed that AMT domain-containing proteins from micro-and macro-algae belonged to either the AMT1 or Rh subfamily, indicating the absence of AMT2 in algae. Gene expression analyses revealed the presence of gametophyte-and sporophyte-specific AMT1 genes that were up-regulated transiently and continually, respectively, under nitrogen-deficient conditions. In addition, up-regulated sporophyte-specific gene expression was suppressed when nitrogen was resupplied. Accordingly, an expansion of the ancient AMT gene has produced AMT1 functional variants differing in temporal and nitrogen starvation-inducible expression patterns during the life cycle of P. yezoensis. These findings help elucidate the unique nutrition starvation responses involving functionally diverse AMT1 and Rh subfamilies in red seaweed.

Impacts of aquaculture nutrient sources: ammonium uptake of commercially important eucheumatoids depends on phosphate levels

“…Several ammonium transporters (AMTs) have been reported in seaweeds. For example, the chlorophyte Ulva linza possesses the AMT1, AMT2 and AMT3 subfamilies of ammonium transporters while the AMT1 subfamily predominates in the rhodophyte Pyropia yezoensis (Li et al 2019;Fan et al 2020). These diverse AMTs could also occur in eucheumatoids which enables them to exhibit distinct responses to PO 4 − 3 levels.…”

Autotrophic and Mixotrophic Growth of an Ammonia Gas-tolerant Bacterium, Paenibacillus lentus NH33 in Ammonia Gas

“…To introduce ionic substrates intracellularly, organisms require the active transporter (channel protein) system [31,32]. NH33 may lack gene sets involved in the active transporter system for nitrogen species uptake or express them at extremely low levels.…”

Auxin Regulates Apical Stem Cell Regeneration and Tip Growth in the Marine Red Alga Neopyropia yezoensis

“…Two filamentous generations in the life cycle of N. yezoensis (strain U-51), conchocelis (sporophyte) and conchosporangium (conchosporophyte), were maintained in sterilized artificial seawater as described by [ 46 ]. The cultures were grown under 60 μmol photons m −2 s −1 light with a long-day photoperiod (14-h light/10-h dark) at 15 °C and aerated with air filtered through a 0.22-μm filter (Whatman, Maidstone, UK).…”