The maize WRKY transcription factor ZmWRKY17 negatively regulates salt stress tolerance in transgenic Arabidopsis plants

Abstract

We cloned and characterized the ZmWRKY17 gene from maize. Overexpression of ZmWRKY17 in Arabidopsis led to increased sensitivity to salt stress and decreased ABA sensitivity through regulating the expression of some ABA- and stress-responsive genes. The WRKY transcription factors have been reported to function as positive or negative regulators in many different biological processes including plant development, defense regulation and stress response. This study isolated a maize WRKY gene, ZmWRKY17, and characterized its role in tolerance to salt stress by generating transgenic Arabidopsis plants. Expression of the ZmWRKY17 was up-regulated by drought, salt and abscisic acid (ABA) treatments. ZmWRKY17 was localized in the nucleus with no transcriptional activation in yeast. Yeast one-hybrid assay showed that ZmWRKY17 can specifically bind to W-box, and it can activate W-box-dependent transcription in planta. Heterologous overexpression of ZmWRKY17 in Arabidopsis remarkably reduced plant tolerance to salt stress, as determined through physiological analyses of the cotyledons greening rate, root growth, relative electrical leakage and malondialdehyde content. Additionally, ZmWRKY17 transgenic plants showed decreased sensitivity to ABA during seed germination and early seedling growth. Transgenic plants accumulated higher content of ABA than wild-type (WT) plants under NaCl condition. Transcriptome and quantitative real-time PCR analyses revealed that some stress-related genes in transgenic seedlings showed lower expression level than that in the WT when treated with NaCl. Taken together, these results suggest that ZmWRKY17 may act as a negative regulator involved in the salt stress responses through ABA signalling.

A Novel Sweetpotato WRKY Transcription Factor, IbWRKY2, Positively Regulates Drought and Salt Tolerance in Transgenic Arabidopsis

“…Ever-changing environmental stresses, such as drought, high salinity, and extreme temperature, have become increasingly major constraints for crop production [1,2]. Drought and soil salinity are two major devastating problems in agriculture and are becoming particularly widespread; therefore, the need to raise the levels of drought and salt tolerance in crops has become crucial [3][4][5]. To respond and adapt to these environmental stresses, plants activate a series of elaborate and sensitive defense mechanisms to promote their survival [5,6].…”

“…Drought and soil salinity are two major devastating problems in agriculture and are becoming particularly widespread; therefore, the need to raise the levels of drought and salt tolerance in crops has become crucial [3][4][5]. To respond and adapt to these environmental stresses, plants activate a series of elaborate and sensitive defense mechanisms to promote their survival [5,6]. The mechanisms of stress tolerance are complex because they can be affected by not only the severity and duration of the stress event but also the plant developmental stage and morphology [7,8].…”

Foreign cry1Ac gene integration and endogenous borer stress-related genes synergistically improve insect resistance in sugarcane

“…Nietzsche et al [36] employed a global transcriptional profiling approach using microarray to identify transcriptional changes in 35S-STKR1 Arabidopsis in order to interpret the observed phenotypic and metabolic changes. Cai et al [37] employed RNA-seq to identify transcriptional changes in transgenic ZmWRKY17 Arabidopsis to reveal salt stress and abscisic acid (ABA) responsive genes in the ABA signaling pathway. Chung et al [38] performed RNA-Seq to identify the direct target genes of the OsNAC proteins in transgenic OsNAC rice and to elucidate the molecular regulatory networks of the root architectures of RCc3:OsNACs for drought tolerance.…”

Peer Review #1 of "Transcription factors involved in abiotic stress responses in Maize (Zea mays L.) and their roles in enhanced productivity in the post genomics era (v0.1)"

“…In maize seedlings, ZmWRKY44 was induced by high temperature, salt stress, ABA, and hydrogen peroxide treatments. Recently, ZmWRKY17 was cloned, characterized and its expression was analyzed in maize seedlings (Cai et al, 2017) (Table. 1). The results showed ZmWRKY17 was induced by ABA, salt and drought stresses.…”