title: Heterologous Overexpression of Poplar SnRK2 Genes Enhanced Salt Stress Tolerance in Arabidopsis thaliana.
abstract: Subfamily 2 of SNF1-related protein kinase (SnRK2) plays important roles in plant abiotic stress responses as a global positive regulator of abscisic acid signaling. In the genome of the model tree Populus trichocarpa, 12 SnRK2 genes have been identified, and some are upregulated by abiotic stresses. In this study, we heterologously overexpressed the PtSnRK2 genes in Arabidopsis thaliana and found that overexpression of PtSnRK2.5 and PtSnRK2.7 genes enhanced stress tolerance. In the PtSnRK2.5 and PtSnRK2.7 overexpressors, chlorophyll content, and root elongation were maintained under salt stress conditions, leading to higher survival rates under salt stress compared with those in the wild type. Transcriptomic analysis revealed that PtSnRK2.7 overexpression affected stress-related metabolic genes, including lipid metabolism and flavonoid metabolism, even under normal growth conditions. However, the stress response genes reported to be upregulated in Arabidopsis SRK2C/SnRK2.6 and wheat SnRK2.8 overexpressors were not changed by PtSnRK2.7 overexpression. Furthermore, PtSnRK2.7 overexpression widely and largely influenced the transcriptome in response to salt stress; genes related to transport activity, including anion transport-related genes, were characteristically upregulated, and a variety of metabolic genes were specifically downregulated. We also found that the salt stress response genes were greatly upregulated in the PtSnRK2.7 overexpressor. Taken together, poplar subclass 2 PtSnRK2 genes can modulate salt stress tolerance in Arabidopsis, through the activation of cellular signaling pathways in a different manner from that by herbal subclass 2 SnRK2 genes.
authors.affiliation: Key Laboratory of Forest Genetics and Biotechnology, Co-Innovation Center for Sustainable Forestry in Southern China, Ministry of Education, Nanjing Forestry UniversityNanjing, China; Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource ScienceYokohama, Japan.
authors.forename: Xueqing
authors.initials: X
authors.lastname: Song
authors.affiliation: Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource Science Yokohama, Japan.
authors.forename: Xiang
authors.initials: X
authors.lastname: Yu
authors.affiliation: Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource Science Yokohama, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Hori
authors.affiliation: Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource ScienceYokohama, Japan; Graduate School of Biological Sciences, Nara Institute of Science and TechnologyIkoma, Japan.
authors.forename: Taku
authors.initials: T
authors.lastname: Demura
authors.affiliation: Biomass Engineering Program Cooperation Division, RIKEN Center for Sustainable Resource ScienceYokohama, Japan; Graduate School of Biological Sciences, Nara Institute of Science and TechnologyIkoma, Japan.
authors.forename: Misato
authors.initials: M
authors.lastname: Ohtani
authors.affiliation: Key Laboratory of Forest Genetics and Biotechnology, Co-Innovation Center for Sustainable Forestry in Southern China, Ministry of Education, Nanjing Forestry University Nanjing, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhuge
keywords: SnRK2; metabolism; overexpression; poplar; salt stress; salt tolerance; transport