Overexpression of transcription factor SlWRKY28 improved the tolerance of Populus davidiana × P. bolleana to alkaline salt stress

Abstract

Background WRKY transcription factors (TFs) have been suggested to play crucial roles in the response to biotic and abiotic stresses. This study is the first to report the alkaline salt regulation of the WRKY gene. Results In this study, we cloned a WRKY gene (SlWRKY28) from the Salix linearistipularis and then transferred to the Populus davidiana × P. bolleana for expression. Sequence analysis on the transcriptome of Salix linearistipular showed the significant up-regulation of WRKY gene expression in response to salt-alkali stress in seedlings. Our data showed that SlWRKY28 localized to the nucleus. Furthermore, the expression of the SlWRKY28 from female plants increased with saline-alkali stress according to the northern blot analysis results. The results of 3,3′-Diaminobenzidine (DAB) staining showed that hydrogen peroxide (H2O2) concentration was lower under stress, but ascorbate peroxidase (APX) enzyme activity was significantly higher in the overexpressed plants than that in non-transgenic (NT) plants. Conclusions We found out the SlWRKY28 induced regulation of the enzyme gene in the reactive oxygen species (ROS) scavenging pathway is a potential mechanism for transgenic lines to improve their resistance to alkaline salt. This study shows theoretical and practical significance in determining SlWRKY28 transcription factors involved in the regulation of alkaline salt tolerance.

Transcriptome Analysis Reveals the Important Role of WRKY28 in Fusarium oxysporum Resistance

“…There are several reports on the resistance functions of the PdpapWRKY28 gene in response to pathogens (Ülker and Somssich, 2004 ; Wu et al, 2011 ), salt stress (Babitha et al, 2013 ; Wang et al, 2020 ), and acids (Chen et al, 2013 ). These studies established a theoretical foundation for our early prediction and subsequent validation experiments.…”

“…Chujo et al ( 2013 ) reported that OsWRKY28 overexpression negatively regulated the innate immune responses of rice against rice blast fungus, resulting in reduced resistance. Wang et al ( 2020 ) reported that overexpression of SlWRKY28 could improve the tolerance of P. davidiana × P. bolleana to alkaline salt stress.…”

Overexpression of Myrothamnus flabellifolia MfWRKY41 confers drought and salinity tolerance by enhancing root system and antioxidation ability in Arabidopsis

“…Plants overexpressing SlWRKY28 showed lower H 2 O 2 concentration and significantly higher ascorbate peroxidase (APX) activity comparing to WT. It was speculated that the regulation of enzyme genes in the ROS clearance pathway induced by SlWRKY28 was the potential mechanism for transgenic plants to improve their resistance to alkali and salinity (Wang et al, 2020). SOD plays a leading role in scavenging ROS, which can catalyze the disproportionation of O 2 − free radicals, maintain the balance of reactive oxygen metabolism, protect cell membrane structure from damage, and mitigate the effects of water stress on plants to a certain extent (Das and Roychoudhury, 2014).…”

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“…There are several reports on the resistance functions of the PdpapWRKY28 gene in response to pathogens (Ülker and Somssich, 2004;Wu et al, 2011), salt stress (Babitha et al, 2013;Wang et al, 2020), and acids (Chen et al, 2013). These studies established a theoretical foundation for our early prediction and subsequent validation experiments.…”