Lower Water Loss Rates Research Articles

New water treatment technology - homogeneous membrane electrodialysis

This paper introduces the structure and technical principle of the homogeneous membrane electrodialyzer, and describes that the homogeneous ion exchange membrane has excellent ion exchange capacity, low water loss rate, stable physical and chemical properties and effective removal of organic matter. The homogeneous membrane electrodialysis technology should be combined with other water treatment processes in practice to achieve better treatment results.

Sitotroga cerealella (Olivier) resilience to extreme temperature and desiccation may explain its increasing pest status in changing climates: Poster

The mechanisms underlying Sitotroga cerealella survival under variable and increasing mean thermal and desiccation environments typical under global change is currently unknown. To understand how S. cerealella survives extreme abiotic stressors typical of stored-grain environments, we measured S. cerealella tolerance temperature and desiccation. The results showed that to survive desiccating grain storage environments, S. cerealella relied more on high body water content (BWC) (70.2 ± 3.72%) compared to lipid reserves (9.8± 0.81%). In desiccating environment, S. cerealella showed a reduced water loss rate (0.056mg/h) (equivalent of 1.81% of body water/hour) which would require 19.31 h to reduce the insect body water to its critical minimum (35.23% body water content at death), which is 50.20% of normal initial body water. Similarly S. cerealella exhibited high basal heat tolerance with critical thermal maximum of 46.09 ± 1.042°C and a heat knockdown time of 7.97 ± 1.64 minutes. Basal cold tolerance was relatively compromised (critical thermal minima of 4.52 ± 1.06°C and chill coma recovery time of 5.80 ±1.17 minutes), following 1h at 0°C. We found no significant correlation (P > 0.001) between BWC and the measured thermal tolerance traits. Low water loss rates reported here may be an evolutionary resistance mechanism for desiccation tolerance. Observed abiotic stress tolerance may explain the ubiquitous distribution of S. cerealella in Africa which is likely to enhance its survival and increase its pest status under global change.

Overexpression of Auxin Binding Protein 57 from Rice (Oryza sativa L.) Increased Drought and Salt Tolerance in Transgenic Arabidopsis thaliana

Auxin plays important roles in many aspects of plant growth and development. It is known that auxin binds to auxin-binding protein (Abp57) and activates the plasma membrane H+-ATPases. In order to elucidate the biological function of rice Abp57 in plants, overexpression transgenic arabidopsis lines were generated. We found overexpression transgenic arabidopsis harbouring rice Abp57 showed tolerance to osmotic stress. Phenotypic transgenic arabidopsis showed longer roots than the wildtype when grown on ½ MS media supplemented with various concentrations of NaCl or PEG-6000. Besides, transgenic arabidopsis has relatively lower water loss rate, higher chlorophyll content and higher biomass when growing under osmotic stress compared to the wildtype. These results suggested that Abp57 has important roles in giving tolerance to arabidopsis against drought and salt stresses.

Overexpression of the ABC transporter gene TsABCG11 increases cuticle lipids and abiotic stress tolerance in Arabidopsis

The cuticle, composed primarily of wax and cutin, covers most plant aerial surfaces and plays a vital role in interactions between plants and their environment. Some ATP-binding cassette G subfamily (ABCG) members are involved in cuticular lipid molecule exportation to outside in the plant surface. Thellungiella salsugineum, a relative of Arabidopsis thaliana with a heavy cuticle, has extreme stress tolerance. TsABCG11, an ABCG transporter was cloned (GenBank accession number JQ389853), and its structure was studied. qRT-PCR showed that TsABCG11 expression varied in different organs of T. salsugineum and was upregulated under ABA, NaCl, drought and cold conditions. The rosette leaves from 4-week-old TsABCG11 overexpressed (OE) Arabidopsis plants displayed lower rates of water loss and decreased chlorophyll-extracted rates compared to wild-type plants. TsABCG11-OE plants also exhibited significantly increased total cuticular wax and cutin monomer amounts, mainly due to prominent changes in the C29, C31, and C33 alkanes in the wax and C18:2 dioic in cutin monomers, respectively. TsABCG11-OE seedlings exhibit lower root growth inhibition under 100 mM of NaCl or 1 µM of ABA than the wild type. Four-week-old TsABCG11-OE plants exhibited higher photosynthetic rates and water-use efficiency under cold stress (4 °C) than control plants. These results indicate that TsABCG11 plays an important role in cuticle lipid exportation and is involved in abiotic stresses, probably having a close relationship with extreme stress tolerance in T. salsugineum.

Interpenetrating polymer networks in polyvinyl alcohol/cellulose nanocrystals hydrogels to develop absorbent materials

Polyvinyl alcohol/cellulose nanocrystals/poly(2-Hydroxyethyl methacrylate) (PVA/CNC/polyHEMA) and PVA/CNC/poly(N'-methylenebisacrylamide) (PVA/CNC/polyMBA) hydrogels were prepared by photo-crosslinking followed by freezing/thawing (F-T) cycle and this novel preparation method was reported. The formation of interpenetrating polymer networks (IPN) resulted from the addition of crosslinking HEMA or MBA monomers displayed improved interfacial adhesion. The produced hydrogels were measured by scanning electron microscopy (SEM), real-time fourier transform infrared (RTIR), thermogravimetric analysis (TGA), mechanical, swelling and adsorption tests. The results showed both PVA/CNC/polyHEMA with semi-IPN and PVA/CNC/polyMBA with dual network (DN) hydrogels had higher thermal stability, lower water loss rate and better swelling and reswelling and mechanical properties, comparing to PVA and PVA/CNC hydrogels. The adsorption behaviors of hydrogels using xylenol orange (XO) and methylene blue (MB) as model dyes were evaluated, indicating that PVA/CNC/polyHEMA and PVA/CNC/polyMBA hydrogels could hold some dyes. Overall, this work provided a good way for increasing mechanical, swelling, reswelling, thermal, and adsorption properties of PVA/CNC, which will be a promising water-manageable material for agriculture application and a candidate for dye carrier.

Comparison of Water Relation in Two Powderpost Beetles Relative to Body Size and Ontogenetic and Behavioral Traits.

Heterobostrychus aequalis (Waterhouse) (Coleoptera: Bostrychidae) and Lyctus africanus Lesne (Coleoptera: Lyctidae) are distributed mainly in tropical regions. The primary mechanism allowing these beetles to survive in cold and arid habitats beyond the native tropical region is a reduced water loss rate. This study investigated the water relations of these two beetles in relation to their size, ontogenetic traits, and behavioral characteristics to determine how they can survive in desiccated wood. H. aequalis and L. africanus share similar water characteristic with beetles living in desert and woodlands. They have high percentage total body water (%TBW) content (58.38 ± 1.86% to 63.20 ± 1.38%), but low %TBW loss (4.28 ± 1.02% to 48.26 ± 8.28%) due to their impermeable cuticle (cuticular permeability [CP] value: 0-15.57 ± 4.90 µg cm-2 h-1 mmHg-1) at all life stages. Although the larvae of L. africanus exhibited relatively high %TBW loss, they had relatively shorter development times that minimized prolonged exposure to dry conditions inside the wood. The aggregative behavior of the adult could be responsible for maintaining a low water loss rate to compensate for their small body size. In contrast, the larvae of H. aequalis had larger body size and significantly lower CP values, allowing them to survive in the desiccated wood for a longer period of time. These results demonstrate the remarkably sophisticated strategies that insects employ as a trade-off between body size, ontogenetic development, and insect sociality (aggregative and non-aggregative behavior) to maintain their water balance in xeric environments.

Estimating isotherm parameters of drying clay for the ceramic industry of Sergipe, Brazil

Abstract The drying process is one of the main stages of production phase of ceramics. Drying without (previous) knowledge of the technological characteristics of clay and the drying parameters may create cracks and deformations in the products. In this study, the models of Page, Henderson & Pabis, Lewis and Midilli were used to evaluate the drying process conditions of five clays used in the ceramic industry in the state of Sergipe, Brazil. The samples in this study were identified as: 1-PIN, 2-IN, 3-PIR, 4-MA and 5-VER, which come from four different deposits in Sergipe and from a deposit in Alagoas. The clays were first characterized through particle size analysis, chemical composition, organic matter content, plasticity index and X-ray diffractometry. Specimens were prepared by axial pressure with 8% moisture and subjected to drying where moisture loss over time was evaluated. The drying parameters were estimated using non-linear adjustments with the GAMS (General Algebraic Modeling System) application. The sum of squared errors (SSE) was used as the objective function and the root mean square error (RMSE) was used as the models performance function. According to the results found, we observed that the Midilli model best described the drying of the five clays, with 5-VER clay presenting drying coefficient of k = 1.442 h−1 and clay 3-PIR presenting k = −0.125 h−1. Thus, 5-VER and 3-PIR clays showed high and low rates of water loss, respectively. These results are consistent with the data obtained through the physical, chemical and structural characterization of clays.

Natural history of a Balaustium sp. (Parasitengona: Erythraeidae) from eastern North America, with emphasis on moisture and temperature requirements

ABSTRACTXeric-suitability and heat tolerance by having a low water loss rate (3%/h) and high upper lethal temperature (48°C) are reported for adults of a Balaustium sp., which match typical hot, dry Balaustium habitat where pollen and arthropod prey on landscape plants are available. They do not have the capacity for water vapour absorption; i.e. the critical equilibrium humidity ≥100% relative humidity with body water losses in unsaturated air. They drink water from droplets, occurring only on occasion and by chance. Prey is their primary source of water. This mite has several features: (1) the inability to recover from heat shock, (2) little heat shock resistance, and (3) no acclimatizing effects by conditioning at a sublethal temperature. In absence of a heat stress-survival mechanism, cooler, shady refuges are sought and used more often that simultaneously help to minimize desiccation risks. This selection for shady spots permits niche differentiation from the bright-red B. murorum, a more desiccation- and heat-resistant species, that coexists in the same habitat and is active in well-lit, sunny locations.

Silencing of OsGRXS17 in rice improves drought stress tolerance by modulating ROS accumulation and stomatal closure

Glutaredoxins (GRXs) modulate redox-dependent signaling pathways and have emerged as key mediators in plant responses to environmental stimuli. Here we report that RNAi-mediated suppression of Oryza sativa GRXS17 (OsGRXS17) improved drought tolerance in rice. Gene expression studies showed that OsGRXS17 was present throughout the plant and that transcript abundance increased in response to drought stress and abscisic acid (ABA) treatment. Localization studies, utilizing GFP-OsGRXS17 fusion proteins, indicated that OsGRXS17 resides in both the cytoplasm and the nuclear envelope. Under drought stress conditions, rice plants with reduced OsGRXS17 expression showed lower rates of water loss and stomatal conductance, higher relative water content, and enhanced survival compared to wild-type controls. Further characterization of the OsGRXS17 down-regulated plants revealed an elevation in H2O2 production within the guard cells, increased sensitivity to ABA, and a reduction in stomatal apertures. The findings demonstrate a critical link between OsGRXS17, the modulation of guard cell H2O2 concentrations, and stomatal closure, expanding our understanding of the mechanisms governing plant responses to drought.

A wheat MYB transcriptional repressor TaMyb1D regulates phenylpropanoid metabolism and enhances tolerance to drought and oxidative stresses in transgenic tobacco plants

MYB transcription factors are involved in the regulation of plant development and response to biotic and abiotic stress. In this study, TaMyb1D, a novel subgroup 4 gene of the R2R3-MYB subfamily, was cloned from wheat (Triticum aestivum L.). TaMyb1D was localized in the nucleus and functioned as a transcriptional repressor. The overexpression of TaMyb1D in tobacco (Nicotiana tabacum) plants repressed the expression of genes related to phenylpropanoid metabolism and down-regulated the accumulation of lignin in stems and flavonoids in leaves. These changes affected plant development under normal conditions. The expression of TaMyb1D was ubiquitous and up-regulated by PEG6000 and H2O2 treatments in wheat. TaMyb1D-overexpressing transgenic tobacco plants exhibited higher relative water content and lower water loss rate during drought stress, as well as higher chlorophyll content in leaves during oxidative stress. The transgenic plants showed a lower leakage of ions as well as reduced malondialdehyde and H2O2 levels during conditions of drought and oxidative stresses. In addition, TaMyb1D up-regulated the expression levels of ROS- and stress-related genes in response to drought stress. Therefore, the overexpression of TaMyb1D enhanced tolerance to drought and oxidative stresses in tobacco plants. Our study demonstrates that TaMyb1D functions as a negative regulator of phenylpropanoid metabolism and a positive regulator of plant tolerance to drought and oxidative stresses.

A Wheat R2R3-type MYB Transcription Factor TaODORANT1 Positively Regulates Drought and Salt Stress Responses in Transgenic Tobacco Plants.

MYB transcription factors play important roles in plant responses to biotic and abiotic stress. In this study, TaODORANT1, a R2R3-MYB gene, was cloned from wheat (Triticum aestivum L.). TaODORANT1 was localized in the nucleus and functioned as a transcriptional activator. TaODORANT1 was up-regulated in wheat under PEG6000, NaCl, ABA, and H2O2 treatments. TaODORANT1-overexpressing transgenic tobacco plants exhibited higher relative water content and lower water loss rate under drought stress, as well as lower Na+ accumulation in leaves under salt stress. The transgenic plants showed higher CAT activity but lower ion leakage, H2O2 and malondialdehyde contents under drought and salt stresses. Besides, the transgenic plants also exhibited higher SOD activity under drought stress. Our results also revealed that TaODORANT1 overexpression up-regulated the expression of several ROS- and stress-related genes in response to both drought and salt stresses, thus enhancing transgenic tobacco plants tolerance. Our studies demonstrate that TaODORANT1 positively regulates plant tolerance to drought and salt stresses.

Variation in the impact of stem scar and cuticle on water loss in highbush blueberry fruit argue for the use of water permeance as a selection criterion in breeding

The role of fruit scar on water loss from fresh harvested, fully blue highbush blueberry (Vaccinium corymbosum L.) fruit was studied on three germplasm lines from each of three half-sib families at University of Talca, Chile. The stem scar of half of the harvested fruit was sealed using nail polish and weight loss of sealed and non-sealed fruit determined daily at 20°C (5 d storage) and bi-weekly at 0°C (15 d storage). Fruit firmness was determined at the end of the storage period. The stem scar accounted for approximately 40% of the moisture lost at 20°C, but percentages varied considerably between lines. While the stem scar covered 0.19% to 0.74% of the fruit surface area, its rate of transpiration was 170-times higher than for the cuticle at 20°C. The larger the fruit scar area, the greater was the absolute rate of water loss, but scar size scar did not affect the rate of weight loss expressed on a per gram fruit basis. Higher levels of water loss were associated with a greater loss in firmness; fruit having a large scar had a greater rate of water loss and were less firm than those having medium or small scars. The water permeance of the fruit cuticle varied two-fold and the apparent permeance of the scar varied three-fold among the 9 lines evaluated when held at 20°C. Interestingly, one line exhibited a 75% lower rate of water loss from its stem scar than the other lines than would be predicted based on its scar diameter. Storage at 0°C reduced the rate of water loss by 90% but the cuticle permeance was not affected by temperature. Sealing the stem scar increased fruit firmness retention at 0°C and 20°C, but provided less benefit at 0°C vs. 20°C. The highly variable nature of water loss through the stem scar and the cuticle in this study suggests that large gains in reductions in water loss are possible for the highbush blueberry once the mechanisms for transpiration are better understood.

Study of phytohormone profile and oxidative metabolism as key process to identification of salinity response in tomato commercial genotypes

Climatic change, intensive agriculture, and worsening water quality induce abiotic stress conditions for plants. Among these factors, salinity stress is a limit factor for plant growth. Therefore, the purpose of this study was to analyze the phytohormones role and oxidative metabolism in response to salt stress of two genotypes of tomato cv. Grand Brix and cv. Marmande RAF, the crops were carried out in a growth chamber. Salinity stress reduces biomass and relative growth rate (RGR) in both genotypes, this effect being greater in cv. Marmande RAF. These results, together with main stress indicator response, the O2.−, indicate that cv. Marmande RAF is more sensitive to Saline stress. Grand Brix showed less oxidative stress, because it presented greater detoxification of the O2−, due to SOD enzyme activity induction and greater antioxidant capacity. Furthermore, Grand Brix has a better hormonal profile adapted to salt stress resistance, the accumulation of IAA, GA4 and CKs and their beneficial role against oxidative stress could make the difference between resistance and sensitivity to salt stress. On the other hand, a lower ACC concentration, ethylene precursor, combined with a greater O2.− detoxification in the cv. Grand Brix could play a fundamental role in tolerance to saline stress. Besides, an increase in ABA levels promotes better stomatal closure, better photosynthesis control and a lower rate of water loss. This data could be essential to select plants with greater resistance to saline stress.

Tomato (Solanum lycopersicum) MADS-box transcription factor SlMBP8 regulates drought, salt tolerance and stress-related genes

Adverse environmental conditions, such as drought, high salinity and extreme temperature, severely affect the growth and productivity of crop plants. MADS-box transcription factors have been described to participate in stress responses. In our study, a MADS-box transcription factor gene, SlMBP8, has been cloned from tomato. The expression of SlMBP8 was induced by Methyl-jasmonic acid (MeJA), high salinity, high temperature, wounding and dehydration. Whereas, the transcript of SlMBP8 was down-regulated by Abscisic acid (ABA), 1-aminocyclopropane-1-carboxylic acid (ACC) and Indole-3-acetic acid (IAA). To further elucidate the function of SlMBP8 gene in response to abiotic stress, plants by knockdown of SlMBP8 through RNA interference (RNAi) were used for investigating the effect of drought and salt stresses on tomato seedlings of wild type (WT) and SlMBP8-RNAi lines. Seedling growth of SlMBP8-RNAi plants was less inhibited by salt than WT at post-germination stage. Transgenic plants became more tolerant to drought and salt stress than WT plants in soil, which was demonstrated by higher levels of chlorophyll and water contents, lower water loss rate and malondialdehyde (MDA) contents. In addition, the expression of multiple stresses related genes were significantly up-regulated in the RNAi lines under control and abiotic stresses. Taken together, these results suggest that SlMBP8 function as a negative stress-responsive transcription factor in the drought and high salinity stress signaling pathways, and may have promising applications in the engineering of drought- and salt-tolerant tomato.

Improved drought tolerance in wheat plants overexpressing a synthetic bacterial cold shock protein gene SeCspA

Cold shock proteins (CSPs) enhance acclimatization of bacteria to adverse environmental circumstances. The Escherichia coli CSP genes CspA and CspB were modified to plant-preferred codon sequences and named as SeCspA and SeCspB. Overexpression of exogenous SeCspA and SeCspB in transgenic Arabidopsis lines increased germination rates, survival rates, and increased primary root length compared to control plants under drought and salt stress. Investigation of several stress-related parameters in SeCspA and SeCspB transgenic wheat lines indicated that these lines possessed stress tolerance characteristics, including lower malondialdehyde (MDA) content, lower water loss rates, lower relative Na+ content, and higher chlorophyll content and proline content than the control wheat plants under drought and salt stresses. RNA-seq and qRT-PCR expression analysis showed that overexpression of SeCsp could enhance the expression of stress-responsive genes. The field experiments showed that the SeCspA transgenic wheat lines had great increases in the 1000-grain weight and grain yield compared to the control genotype under drought stress conditions. Significant differences in the stress indices revealed that the SeCspA transgenic wheat lines possessed significant and stable improvements in drought tolerance over the control plants. No such improvement was observed for the SeCspB transgenic lines under field conditions. Our results indicated that SeCspA conferred drought tolerance and improved physiological traits in wheat plants.

Genome-wide analysis of the HD-ZIP IV transcription factor family in Gossypium arboreum and GaHDG11 involved in osmotic tolerance in transgenic Arabidopsis.

HD-ZIP IV proteins belong to the homeodomain-leucine zipper (HD-ZIP) transcription factor family and are involved in trichome development and drought stress in plants. Although some functions of the HD-ZIP IV group are well understood in Arabidopsis, little is known about their function in cotton. In this study, HD-ZIP genes were identified from three Gossypium species (G. arboreum, G. raimondii and G. hirsutum) and clustered into four families (HD-ZIP I, II, III and IV) to separate HD-ZIP IV from the other three families. Systematic analyses of phylogeny, gene structure, conserved domains, and expression profiles in different plant tissues and the expression patterns under osmotic stress in leaves were further conducted in G. arboreum. More importantly, ectopic overexpression of GaHDG11, a representative of the HD-ZIP IV family, confers enhanced osmotic tolerance in transgenic Arabidopsis plants, possibly due to elongated primary root length, lower water loss rates, high osmoprotectant proline levels, significant levels of antioxidants CAT, and/or SOD enzyme activity with reduced levels of MDA. Taken together, these observations may lay the foundation for future functional analysis of cotton HD-ZIP IV genes to unravel their biological roles in cotton.

Silencing of SlHB2 Improves Drought, Salt Stress Tolerance, and Induces Stress-Related Gene Expression in Tomato

Adverse environmental conditions, such as drought, high salinity, and extreme temperature, severely affect the growth and productivity of crop plants. HD-Zip I transcription factors have been described to be involved in stress responses. In the present study, a novel transcription factor gene, SlHB2, from the HD-Zip I subfamily has been cloned from tomato. The expression of SlHB2 was induced by ABA, ACC, MeJA, dehydration, high-salinity, low-temperature, and wounding. To investigate the function of SlHB2 in response to abiotic stress, tomato seedlings of SlHB2-RNAi lines were exposed to drought and salt stresses. Higher levels of chlorophyll and water contents, lower water loss rate and MDA contents were detected in the leaves of transgenic plants compared to those in wild type under stress conditions, which was consistent with the enhanced tolerance of SlHB2-RNAi lines to drought and salt stresses. Significant up-regulation of multiple stress-related genes was also observed in the RNAi lines under normal and/or abiotic stresses. Taken together, the results suggest that the transcription factor SlHB2 acts as a negative regulator in the drought and high-salinity stress signaling pathways.

A CBL-Interacting Protein Kinase TaCIPK2 Confers Drought Tolerance in Transgenic Tobacco Plants through Regulating the Stomatal Movement.

In plants, the CBL-CIPK signaling pathways play key roles in the response to abiotic stresses. However, functional studies of CIPKs in the important staple crop wheat are very rare. In this study, we identified a CIPK gene from wheat, designated TaCIPK2. Expression analysis results showed that TaCIPK2 could be up-regulated in wheat leaves by polyethylene glycol, abscisic acid and H2O2 treatments. Subcellular localization analyses revealed that TaCIPK2 was present in whole wheat epidermal cells. A yeast two-hybrid assay indicated that TaCIPK2 interacted with TaCBL1, 2, 3 and 4 in vitro. Transgenic tobacco plants over-expressing TaCIPK2 exhibited increased drought tolerance, indicated by a larger proportion of green cotyledons and higher survival rates under the osmotic and drought stress conditions compared with control plants. Additionally, physiological index analyses revealed that the transgenic tobacco plants had lower water loss rates and ion leakage, accumulated less malondialdehyde and H2O2, and had higher catalase and superoxide dismutase activities than the control plants. The transgenic plants also exhibited faster stomatal closure following exposure to osmotic stress conditions. The seed germination rates and stomatal aperture of TaCIPK2-overexpressing tobacco plants decreased after exogenous abscisic acid treatment was applied, implying that the transgenic tobacco plants were more sensitive to exogenous abscisic acid than the control plants. Our results indicate that TaCIPK2 plays a positive regulatory role in drought stress responses in transgenic tobacco plants.

Overexpression of wheat TaNCED gene in Arabidopsis enhances tolerance to drought stress and delays seed germination

Abscisic acid (ABA) regulates various plant physiological processes, especially participates in the plant responses to harsh environments. The 9-cis-epoxycarotenoid dioxygenase (NCED) is a key enzyme in ABA biosynthesis pathway. Here, a TaNCED with an 1 887-bp open reading frame was cloned from wheat, which encodes a peptide of 628 amino acids. A chloroplast transit peptide sequence was found at the N-terminus of the TaNCED protein. Multiple sequence alignments indicate that the TaNCED protein shared high similarities with other NCEDs from different species. Real-time quantitative PCR analysis shows that expression of TaNCED was strongly up-regulated by treatments with ABA, polyethylene glycol, and drought stress, and it was down-regulated during germination of the wheat seeds. Ectopic overexpression of the TaNCED gene in Arabidopsis resulted in an increase of endogenous ABA and free proline content. A lower water loss rate and stomatal conductance of leaves were found in the transgenic plants in comparison with the wild type. Subsequently, the transgenic plants displayed an enhanced tolerance to drought stress but delayed seed germination. These data provide evidence that the TaNCED might play a primary role in regulation of ABA content during water stress and seed dormancy.

Drought-responsive WRKY transcription factor genes TaWRKY1 and TaWRKY33 from wheat confer drought and/or heat resistance in Arabidopsis.

BackgroundDrought stress is one of the major causes of crop loss. WRKY transcription factors, as one of the largest transcription factor families, play important roles in regulation of many plant processes, including drought stress response. However, far less information is available on drought-responsive WRKY genes in wheat (Triticum aestivum L.), one of the three staple food crops.ResultsForty eight putative drought-induced WRKY genes were identified from a comparison between de novo transcriptome sequencing data of wheat without or with drought treatment. TaWRKY1 and TaWRKY33 from WRKY Groups III and II, respectively, were selected for further investigation. Subcellular localization assays revealed that TaWRKY1 and TaWRKY33 were localized in the nuclei in wheat mesophyll protoplasts. Various abiotic stress-related cis-acting elements were observed in the promoters of TaWRKY1 and TaWRKY33. Quantitative real-time PCR (qRT-PCR) analysis showed that TaWRKY1 was slightly up-regulated by high-temperature and abscisic acid (ABA), and down-regulated by low-temperature. TaWRKY33 was involved in high responses to high-temperature, low-temperature, ABA and jasmonic acid methylester (MeJA). Overexpression of TaWRKY1 and TaWRKY33 activated several stress-related downstream genes, increased germination rates, and promoted root growth in Arabidopsis under various stresses. TaWRKY33 transgenic Arabidopsis lines showed lower rates of water loss than TaWRKY1 transgenic Arabidopsis lines and wild type plants during dehydration. Most importantly, TaWRKY33 transgenic lines exhibited enhanced tolerance to heat stress.ConclusionsThe functional roles highlight the importance of WRKYs in stress response.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0806-4) contains supplementary material, which is available to authorized users.