Ectopic Expression of JcWRKY Transcription Factor Confers Salinity Tolerance via Salicylic Acid Signaling

Abstract

Plants, being sessile, have developed intricate signaling network to specifically respond to the diverse environmental stress. The plant-specific WRKY TFs form one of the largest TF family and are involved in diverse plant processes, involving growth, development and stress signaling through auto and cross regulation with different genes and TFs. Here, we report the functional characterization of a salicylic acid -inducible JcWRKY TF. The JcWRKY overexpression confers salinity tolerance in transgenic tobacco, as was evident by increased chlorophyll content and seed germination potential. The transgenic plants showed increased soluble sugar, membrane stability, reduced electrolyte leakage and generation of reactive oxygen species (H2O2 and O2•-) as compared to the wild type. Furthermore, the low SA treatment along with salinity improved the tolerance potential of the transgenics by maintaining ROS homeostasis and high K+/Na+ ratio. The transcript expression of SA biosynthetic gene ICS1 and antioxidative enzymes (CAT and SOD) showed upregulation during stress. Thus, the present study reflects that JcWRKY is working in co-ordination with SA signaling to orchestrate the different biochemical and molecular pathways to maneuvre salt stress tolerance of the transgenic plants.

Overexpression of the alfalfa WRKY11 gene enhances salt tolerance in soybean

“…Chlorophyll content is a vital factor that can be used to determine the quality of plant growth. Overexpression of ThWRKY4 in Arabidopsis increased the chlorophyll contents significantly in transgenic lines as compared to the control [ 57 ], and JcWRKY overexpression in tobacco resulted in higher chlorophyll content compared with the wild type under salt stress [ 35 ]. Similarly, MsWRKY11 overexpression in soybean increased the chlorophyll levels in transgenic plants as compared to those in wild-type plants under salt stress conditions ( Fig 8 ).…”

“…Currently, studies use physiological indicators as a standard for plant stress resistance analysis. ThWRKY4 overexpression increases the tolerance of Arabidopsis to salt, oxidative, and ABA stress; improves SOD and POD activity; reduces the levels of ROS; and decreases the rate of cell death [ 35 ]. Overexpression of DgWRKY3 in transgenic tobacco plants has been found to result in higher activity of antioxidant enzymes, including those of SOD, POD, and CAT, under salt stress [ 36 ].…”

Comparison between the impacts of two different modes of salicylic acid application on tomato (Solanum lycopersicum) responses to salinity

“…This may allow primed plants, at least to some extent, to respond differently than untreated plants when subsequently exposed to salt stress. 23 In contrast, a concomitant application of SA and NaCl should reinforce the specific function of SA as a signaling molecule directly involved in salt tolerance 11,24,25 and focus on properties directly affected by NaCl independently of any preliminary modifications. Surprisingly, comparison between the two modes of application has never been performed until now to the best of our knowledge, although this can afford precious information regarding the modalities of SA impact in salt tolerance.…”

Patterns of Drought Response of 38 WRKY Transcription Factors of Zanthoxylum bungeanum Maxim.

“…Salt tolerance zinc finger (STZ) transcriptional repressors are involved in abiotic stress responses and can inhibit the stress response genes DREB1A and LTI78 . In addition, STZ may also be involved in the early signal response of JA, regulate the expression of the JA biosynthesis gene LOX3 , and control the expression of TIFY10A / JAZ1 , which is a key repressor in the JA signaling cascade [32,33]. Moreover, MYC2 is a major positive regulator of JA gene expression and is capable of binding to the G-box region upstream of the JA gene to increase gene expression level [34].…”