The PalERF109 transcription factor positively regulates salt tolerance via PalHKT1;2 in Populus alba var. pyramidalis

Abstract

Salinity restricts the growth of trees to varying extents, but the regulatory mechanisms involved in their varying salt tolerance are largely unknown. In an effort to elucidate these mechanisms, we identified a total of 99 genes in the Ethylene Responsive Factor (ERF) family of transcription factors and examined their expression patterns under salt stress in Populus alba var. pyramidalis. We found that a B4 group gene, PalERF109, was rapidly induced by salt treatment and preferentially expressed in stems and petioles, where it is probably involved in transport of ions and water in xylem. Overexpression of PalERF109 enhanced the salt tolerance of the poplar, and further analysis showed that it directly upregulated a high-affinity K+transporter (HKT) gene, PalHKT1;2. The results clearly indicate that PalERF109 enhances salt tolerance at least partially through direct activation of PalHKT1;2 and extends understanding of the roles of ERF genes in tree stress responses.

Effect of Overexpression of JERFs on Intracellular K+/Na+ Balance in Transgenic Poplar (Populus alba × P. berolinensis) Under Salt Stress

“…JERF36s belong to the ERF transcription factor class, which are involved in signal transduction, hormone synthesis, and stress responses (Li et al, 2009;Zhang and Huang, 2010;Su et al, 2011). Previous researches have demonstrated that ERF transcription factors could enhance stress resistance in A. thaliana, N. tabacum, Lilium longifloruma, and Populus (Gilmour et al, 2000;Wang et al, 2004;Li et al, 2006;Li et al, 2009;Su et al, 2011;Yao et al, 2016;Yao et al, 2017;Charfeddine et al, 2019;Chen et al, 2020;Jiang et al, 2020). Expression of JERFs activates the expression of resistanceassociated genes and promotes the ability of plants to adapt to environmental stress.…”

“…Overexpression of ERF76 in transgenic poplar upregulated the expression of 16 transcription factor genes and 45 stress-related genes and also increased the ability of ABA and GA (gibberellic acid) biosynthesis, which resulted in stronger tolerance to salt stress (Yao et al, 2016). Overexpression of PalERF109 increased the transcript abundance of salt stressrelated genes, enhanced the ABA signaling pathway, and induced expression of salt many ion channel proteins as well as transporters in transgenic poplars with higher salt tolerance (Chen et al, 2020). Plant hormones and plant hormone signaling pathways regulate complex signaling networks related to plant development and responses to environmental stresses (Bari and Jones, 2009;Zhu, 2016).…”

“…The application of genetic engineering and transformation technology provides effective means of improving salt tolerance of poplar by introducing known salt-responsive genes into Populus (Jansson and Douglas, 2007;Li et al, 2009;Su et al, 2011;Ye et al, 2011;Zhou et al, 2014;Yao et al, 2017;Zhang X. N. et al, 2019). Many studies have shown that inroducing transcription factors (TFs) genes into plants is generally more efficient than structural genes, because TFs usually regulate the expression of many target genes in related pathways, leading to enhanced stress torlance in plants (Mcgrath et al, 2005;Li et al, 2009;Su et al, 2011;Licausi et al, 2013;Karim et al, 2015;Yao et al, 2016;Wei et al, 2017;Charfeddine et al, 2019;Zhang C. H et al, 2019;Zhang X. N. et al, 2019;Chen et al, 2020;Jiang et al, 2020). Ethylene responsive factors (ERFs), which have a characteristic AP2/ERF DNA-binding domain, comprise one of the largest TF families in plants (Riechmann et al, 2000;Nakano et al, 2006;Licausi et al, 2013;Zhang X. N. et al, 2019;Chen et al, 2020).…”

“…Many studies have shown that inroducing transcription factors (TFs) genes into plants is generally more efficient than structural genes, because TFs usually regulate the expression of many target genes in related pathways, leading to enhanced stress torlance in plants (Mcgrath et al, 2005;Li et al, 2009;Su et al, 2011;Licausi et al, 2013;Karim et al, 2015;Yao et al, 2016;Wei et al, 2017;Charfeddine et al, 2019;Zhang C. H et al, 2019;Zhang X. N. et al, 2019;Chen et al, 2020;Jiang et al, 2020). Ethylene responsive factors (ERFs), which have a characteristic AP2/ERF DNA-binding domain, comprise one of the largest TF families in plants (Riechmann et al, 2000;Nakano et al, 2006;Licausi et al, 2013;Zhang X. N. et al, 2019;Chen et al, 2020). Overexpression of ERFs genes can effectively improve salt tolarence of plant under salt stress, such as ERF96 (in Arabidopsis thaliana) (Jiang et al, 2020), StERF94 (in potato) (Charfeddine et al, 2019), ERF76 (in di-haploid P. simonii × P. nigra) (Yao et al, 2016;Yao et al, 2017;Yao et al, 2019), PalERF109 (in P. alba var.…”

“…Overexpression of ERFs genes can effectively improve salt tolarence of plant under salt stress, such as ERF96 (in Arabidopsis thaliana) (Jiang et al, 2020), StERF94 (in potato) (Charfeddine et al, 2019), ERF76 (in di-haploid P. simonii × P. nigra) (Yao et al, 2016;Yao et al, 2017;Yao et al, 2019), PalERF109 (in P. alba var. pyramidalis) (Chen et al, 2020), and JERFs (in tomato) (Li et al, 2009;Su et al, 2011).…”