The Kandelia obovata transcription factor KoWRKY40 enhances cold tolerance in transgenic Arabidopsis

Abstract

Background WRKY transcription factors play key roles in plant development processes and stress response. Kandelia obovata is the most cold-resistant species of mangrove plants, which are the important contributors to coastal marine environment. However, there is little known about the WRKY genes in K. obovata. Results In this study, a WRKY transcription factor gene, named KoWRKY40, was identified from mangrove plant K. obovata. The full-length cDNA of KoWRKY40 gene was 1420 nucleotide bases, which encoded 318 amino acids. The KoWRKY40 protein contained a typical WRKY domain and a C2H2 zinc-finger motif, which were common signatures to group II of WRKY family. The three-dimensional (3D) model of KoWRKY40 was formed by one α-helix and five β-strands. Evolutionary analysis revealed that KoWRKY40 has the closest homology with a WRKY protein from another mangrove plant Bruguiera gymnorhiza. The KoWRKY40 protein was verified to be exclusively located in nucleus of tobacco epidermis cells. Gene expression analysis demonstrated that KoWRKY40 was induced highly in the roots and leaves, but lowly in stems in K. obovata under cold stress. Overexpression of KoWRKY40 in Arabidopsis significantly enhanced the fresh weight, root length, and lateral root number of the transgenic lines under cold stress. KoWRKY40 transgenic Arabidopsis exhibited higher proline content, SOD, POD, and CAT activities, and lower MDA content, and H2O2 content than wild-type Arabidopsis under cold stress condition. Cold stress affected the expression of genes related to proline biosynthesis, antioxidant system, and the ICE-CBF-COR signaling pathway, including AtP5CS1, AtPRODH1, AtMnSOD, AtPOD, AtCAT1, AtCBF1, AtCBF2, AtICE1, AtCOR47 in KoWRKY40 transgenic Arabidopsis plants. Conclusion These results demonstrated that KoWRKY40 conferred cold tolerance in transgenic Arabidopsis by regulating plant growth, osmotic balance, the antioxidant system, and ICE-CBF-COR signaling pathway. The study indicates that KoWRKY40 is an important regulator involved in the cold stress response in plants.

Comprehensive analysis of the NAC transcription factor gene family in Kandelia obovata reveals potential members related to chilling tolerance

“…In PCC analysis, a total of 10 WRKY, 4 ERF, 1 GATA, 2 MYB-related proteins and 2 zinc finger TFs were found to be positively correlated with the expression of NACs, suggesting that a variety of TFs were involved in the adaptation process when K. obovata was subjected to low-temperature stress. Recently, Fei et al (2022) reported that KoWRKY40 was highly induced in leaves and roots under 5°C cold stress, ectopic overexpression of the KoWRKY40 gene in A. thaliana significantly enhanced the low-temperature tolerance of transgenic plants and increased the expression of antioxidant enzyme and COR genes. KoWRKY40 is highly homologous to GWHTACBH004052 in this study, which is significantly and positively correlated with the expression of KoNAC25, KoNAC8 and KoNAC33.…”

Genome-wide investigation of the WRKY transcription factor gene family in weeping forsythia: expression profile and cold and drought stress responses

“…Under cold stress, 17 WRKY genes showed significant response expression, and 9 of the 17 genes had low temperature responsiveness cis-elements, which further confirmed that these genes were indeed related to cold stress. Previous studies have also confirmed that WRKY genes play important roles in improving cold tolerance in plants (Kim et al 2016 ; Fei et al 2022 ). Other genes which did not have low temperature responsiveness cis-elements might be activated by other signal pathways.…”

Importance of FaWRKY71 in Strawberry (Fragaria × ananassa) Fruit Ripening

“…Many studies have shown that WRKY conferred cold tolerance in a variety of plants. KoWRKY40 transgenic Arabidopsis plants exhibited higher SOD, POD, and CAT activities, and lower MDA content under cold stress [ 31 ]. CsWRKY46 from cucumber endowed transgenic plants with cold tolerance and positively regulated cold signaling pathway, specifically interact with the W-box in the promoter of ABA-responsive transcription factor ABI5.…”