AUTHOR=Song Xueqing , Yu Xiang , Hori Chiaki , Demura Taku , Ohtani Misato , Zhuge Qiang 

TITLE=Heterologous Overexpression of Poplar SnRK2 Genes Enhanced Salt Stress Tolerance in Arabidopsis thaliana

JOURNAL=Frontiers in Plant Science

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2016.00612

DOI=10.3389/fpls.2016.00612

ISSN=1664-462X

ABSTRACT=<p>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 <italic>Populus trichocarpa</italic>, 12 <italic>SnRK2</italic> genes have been identified, and some are upregulated by abiotic stresses. In this study, we heterologously overexpressed the <italic>PtSnRK2</italic> genes in <italic>Arabidopsis thaliana</italic> and found that overexpression of <italic>PtSnRK2.5</italic> and <italic>PtSnRK2.7</italic> genes enhanced stress tolerance. In the <italic>PtSnRK2.5</italic> and <italic>PtSnRK2.7</italic> 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 <italic>PtSnRK2.7</italic> 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 <italic>SRK2C/SnRK2.6</italic> and wheat <italic>SnRK2.8</italic> overexpressors were not changed by <italic>PtSnRK2.7</italic> overexpression. Furthermore, <italic>PtSnRK2.7</italic> 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 <italic>PtSnRK2.7</italic> overexpressor. Taken together, poplar subclass 2 <italic>PtSnRK2</italic> 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 <italic>SnRK2</italic> genes.</p>