The Halophyte Halostachys caspica AP2/ERF Transcription Factor HcTOE3 Positively Regulates Freezing Tolerance in Arabidopsis

Abstract

The APETALA2 (AP2) and ethylene-responsive element-binding factor (ERF) gene family is one of the largest plant-specific transcription factor gene families, which plays a critical role in plant development and evolution, as well as response to various stresses. The TARGET OF EAT3 (TOE3) gene is derived from Halostachys caspica and belongs to the AP2 subfamily with two AP2 DNA-binding domains. Currently, AP2 family mainly plays crucial roles in plant growth and evolution, yet there are few reports about the role of AP2 in abiotic stress tolerance. Here, we report HcTOE3, a new cold-regulated transcription factor gene, which has an important contribution to freezing tolerance. The main results showed that the expression of HcTOE3 in the H. caspica assimilating branches was strongly induced by different abiotic stresses, including high salinity, drought, and extreme temperature (heat, chilling, and freezing), as well as abscisic acid and methyl viologen treatments. Overexpressing HcTOE3 gene (OE) induced transgenic Arabidopsis plant tolerance to freezing stress. Under freezing treatment, the OE lines showed lower content of malondialdehyde and electrolyte leakage and less accumulation of reactive oxygen species compared with the wild type. However, the survival rates, antioxidant enzyme activities, and contents of osmotic adjustment substance proline were enhanced in transgenic plants. Additionally, the OE lines increased freezing tolerance by up-regulating the transcription level of cold responsive genes (CBF1, CBF2, COR15, COR47, KIN1, and RD29A) and abscisic acid signal transduction pathway genes (ABI1, ABI2, ABI5, and RAB18). Our results suggested that HcTOE3 positively regulated freezing stress and has a great potential as a candidate gene to improve plant freezing tolerance.

Herbaceous peony AP2/ERF transcription factor binds the promoter of the tryptophan decarboxylase gene to enhance high‐temperature stress tolerance

“…In this study, PlTOE3 expression was induced by high temperature, which was a nuclear-localized protein. These results were consistent with a previous study (Yin et al, 2021).…”

“…In this study, PlTOE3 expression was induced by high temperature, which was a nuclear‐localized protein. These results were consistent with a previous study (Yin et al, 2021). However, few studies have focused on the role of TOE3 in high‐temperature stress tolerance, whereas our results suggested that PlTOE3 positively regulated high‐temperature stress; thus, it may be a candidate gene for improving high‐temperature stress tolerance in plants.…”

“…When TOE3was concerned, it has been identified in several plant species. Jung et al (2014) found that transgenic induced transgenic A. thaliana plant tolerance to freezing stress (Yin et al, 2021). In this study, PlTOE3 expression was induced by high temperature, which was a nuclear-localized protein.…”

“…Jung et al (2014) found that transgenic A. thaliana plants overexpressing AtTOE3 exhibited indeterminate flowers with numerous stamens and carpelloid organs. In Halostachys caspica , the expression of HcTOE3 was strongly induced by different abiotic stresses, and overexpressing HcTOE3 induced transgenic A. thaliana plant tolerance to freezing stress (Yin et al, 2021). In this study, PlTOE3 expression was induced by high temperature, which was a nuclear‐localized protein.…”

Physiological, Transcriptomic Investigation on the Tea Plant Growth and Yield Motivation by Chitosan Oligosaccharides

“…The tea leaves (0.2 g) were grounded with 1mL stilled water for both the control and COS treatment group. Additionally, the homogenate was then transferred into a centrifuge tube and centrifuged at 8000 g for 10 min at 4 • C. The supernatant was subjected to a spectrophotometer, which analyzes the liquid by measuring the amount of light that is absorbed by it [25,26]. Thus, the enzyme activity, soluble sugar and chlorophyll content were accordingly obtained by following provisions in bioassay kits as reported [24].…”