A Wheat WRKY Transcription Factor TaWRKY10 Confers Tolerance to Multiple Abiotic Stresses in Transgenic Tobacco

Abstract

WRKY transcription factors are reported to be involved in defense regulation, stress response and plant growth and development. However, the precise role of WRKY transcription factors in abiotic stress tolerance is not completely understood, especially in crops. In this study, we identified and cloned 10 WRKY genes from genome of wheat (Triticum aestivum L.). TaWRKY10, a gene induced by multiple stresses, was selected for further investigation. TaWRKY10 was upregulated by treatment with polyethylene glycol, NaCl, cold and H2O2. Result of Southern blot indicates that the wheat genome contains three copies of TaWRKY10. The TaWRKY10 protein is localized in the nucleus and functions as a transcriptional activator. Overexpression of TaWRKY10 in tobacco (Nicotiana tabacum L.) resulted in enhanced drought and salt stress tolerance, mainly demonstrated by the transgenic plants exhibiting of increased germination rate, root length, survival rate, and relative water content under these stress conditions. Further investigation showed that transgenic plants also retained higher proline and soluble sugar contents, and lower reactive oxygen species and malonaldehyde contents. Moreover, overexpression of the TaWRKY10 regulated the expression of a series of stress related genes. Taken together, our results indicate that TaWRKY10 functions as a positive factor under drought and salt stresses by regulating the osmotic balance, ROS scavenging and transcription of stress related genes.

Wheat WRKY Type Transcription Factor Gene TaWRKY1 is Essential in Mediating Drought Tolerance Associated with an ABA-Dependent Pathway

“…The nucleus localization after translation and the up-regulated expression pattern upon drought and exogenous ABA indicates that TaWRKY1 is possibly involved in mediating drought responses through an ABA-dependent pathway. Several lines of evidence have shown that a subset of the WRKY family genes are functional in mediating plant tolerance to drought stress, through their roles in modulating the physiological processes associated with defensiveness of drought or related osmotic stresses (Ishiguro and Nakamura 1994;Niu et al 2012;Wang et al 2013;Sun and Yu 2015;Jia et al 2015). For instance, TaWRKY2, TaWRKY19, and TaWRKY10, the WRKY family genes in wheat, function effectively in responses to a set of abiotic stresses, such as drought, high salinity, low temperature, wounding, and the external ABA application via improvement of osmolyte accumulation and cellular ROS homeostasis (Niu et al 2012;Wang et al 2013).…”

“…Niu et al 2012;Wang et al 2013), cotton (Gossypium hirsutum) (Jia et al 2015), and soybean (Glycine max) (Liao et al 2008). In addition, numerous WRKY family genes throughout the lower plant species, such as fern (Ceratopteris richardii), moss (Physcomitrella patens), green algae (Chlamydomonas reinhardtii), diplomonads (Giardia lamblia), and amoebozoa (Dictyostelium discoideum) (Ulker and Somssich 2004;Zhang and Wang 2005), have also been characterized to date.…”

Genome-Wide Analysis of the WRKY Transcription Factors in <b><i>Aegilops tauschii</i></b>

“…Due to the complexity of the wheat genome, the genome sequencing has not yet been completed. This severely impacts the discovery of new genes, and only 40 WRKY TFs with complete CDSs have been identified, only few of which have been further analyzed [Niu et al, 2012;Wang et al, 2013]. In this study, we first deeply excavated the full-length WRKY TFs via comprehensive analysis of the A. tauschii genome, which is the D-genome progenitor of the wheat genome.…”

“…Overexpression of TaWRKY2 or TaWRKY19 in Arabidopsis resulted in an increased salt and drought tolerance compared with controls [Niu et al, 2012]. TaWRKY10 could also enhance the tolerance for abiotic stress by overexpression in tobacco [Wang et al, 2013]. In addition, many WRKY TFs were shown to be involved in responding to biotic and abiotic stress in other plants, such as barley, Retama raetam, Thlaspi caerulescens , and soybeans [Pnueli et al, 2002;Marè et al, 2004;Wei et al, 2008;Zhou et al, 2008].…”

Identification and Functional Analysis of the NADK Gene Family in Wheat

“…Germinated seeds of maize were directly sown in Sunshine MVP potting soil and then grown in a growth chamber under 16-h light/8-h dark conditions at 25±1°C. Following 2 weeks of growth, the seedlings were grown at 4 and 40°C for cold and heat treatments, respectively, for 12 and 24 h. The seedlings were submerged in 200 mM NaCl or 20 % PEG6000 solutions for salt and drought treatments, respectively, for 12 and 24 h (Qin et al 2008;Mao et al 2010;Niu et al 2012;Zhang et al 2012b;Wang et al 2013a). For the oxidative stress and hormone treatments, solutions of 30 μM MV, 100 μM MeJA and 100 μM ABA were individually sprayed on seedlings and then the plants were allowed to grow for 12 and 24 h (Zhang et al 2012b;Niu et al 2012;Mao et al 2010).…”