Antarctic Moss Multiprotein Bridging Factor 1c Overexpression in Arabidopsis Resulted in Enhanced Tolerance to Salt Stress

is one of the moss species that survives extreme conditions in the Antarctic. In order to explore the functional benefits of moss genetic resources, multiprotein-bridging factor 1c gene ( ) was isolated and characterized. The deduced amino acid sequence of PaMBF1c comprises of a multiprotein-bridging factor (MBF1) domain and a helix-turn-helix (HTH) domain. expression was induced by different abiotic stresses in , implying its roles in stress responses. We overexpressed in Arabidopsis and analyzed the resulting phenotypes in comparison with wild type and/or Arabidopsis ( ) overexpressors. Overexpression of in Arabidopsis resulted in enhanced tolerance to salt and osmotic stress, as well as to cold and heat stress. More specifically, enhanced salt tolerance was observed in overexpressors in comparison to wild type but not clearly observable in overexpressing lines. Thus, these results implicate the evolution of under salt-enriched Antarctic soil. RNA-Seq profiling of NaCl-treated plants revealed that 10 salt-stress inducible genes were already up-regulated in overexpressing plants even before NaCl treatment. Gene ontology enrichment analysis with salt up-regulated genes in each line uncovered that the terms lipid metabolic process, ion transport, and cellular amino acid biosynthetic process were significantly enriched in overexpressors. Additionally, gene enrichment analysis with salt down-regulated genes in each line revealed that the enriched categories in wild type were not significantly overrepresented in overexpressing lines. The up-regulation of several genes only in overexpressing lines suggest that enhanced salt tolerance in -OE might involve reactive oxygen species detoxification, maintenance of ATP homeostasis, and facilitation of Ca signaling. Interestingly, many salt down-regulated ribosome- and translation-related genes were not down-regulated in overexpressing lines under salt stress. These differentially regulated genes by overexpression could contribute to the enhanced tolerance in overexpressing lines under salt stress.