Expression Levels Of Stress-related Genes Research Articles

Overexpression of Potato PYL16 Gene in Tobacco Enhances the Transgenic Plant Tolerance to Drought Stress.

PYR/PYL/RCAR proteins are abscisic acid (ABA) receptors that play a crucial role in plant responses to abiotic stresses. However, there have been no research reports on potato PYL so far. In this study, a potato PYL gene named StPYL16 was identified based on transcriptome data under drought stress. Molecular characteristics analysis revealed that the StPYL16 protein possesses an extremely conserved PYL family domain. The tissue expression results indicated that the StPYL16 is predominantly expressed at high levels in the underground parts, particularly in tubers. Abiotic stress response showed that StPYL16 has a significant response to drought treatment. Further research on the promoter showed that drought stress could enhance the activation activity of the StPYL16 promoter on the reporter gene. Then, transient and stable expression of StPYL16 in tobacco enhanced the drought resistance of transgenic plants, resulting in improved plant height, stem thickness, and root development. In addition, compared with wild-type plants, StPYL16 transgenic tobacco exhibited lower malondialdehyde (MDA) content, higher proline accumulation, and stronger superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities. Meanwhile, StPYL16 also up-regulated the expression levels of stress-related genes (NtSOD, NtCAT, NtPOD, NtRD29A, NtLEA5, and NtP5CS) in transgenic plants under drought treatment. These findings indicated that the StPYL16 gene plays a positive regulatory role in potato responses to drought stress.

Heterologous Expression of Chrysanthemum TCP Transcription Factor CmTCP13 Enhances Salinity Tolerance in Arabidopsis.

Plant-specific TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) proteins play critical roles in plant development and stress responses; however, their functions in chrysanthemum (Chrysanthemum morifolium) have not been well-studied. In this study, we isolated and characterized the chrysanthemum TCP transcription factor family gene CmTCP13, a homolog of AtTCP13. This gene encoded a protein harboring a conserved basic helix-loop-helix motif, and its expression was induced by salinity stress in chrysanthemum plants. Subcellular localization experiments showed that CmTCP13 localized in the nucleus. Sequence analysis revealed the presence of multiple stress- and hormone-responsive cis-elements in the promoter region of CmTCP13. The heterologous expression of CmTCP13 in Arabidopsis plants enhanced their tolerance to salinity stress. Under salinity stress, CmTCP13 transgenic plants exhibited enhanced germination, root length, seedling growth, and chlorophyll content and reduced relative electrical conductivity compared with those exhibited by wild-type (WT) plants. Moreover, the expression levels of stress-related genes, including AtSOS3, AtP5CS2, AtRD22, AtRD29A, and AtDREB2A, were upregulated in CmTCP13 transgenic plants than in WT plants under salt stress. Taken together, our results demonstrate that CmTCP13 is a critical regulator of salt stress tolerance in plants.

Characterization of bZIP Transcription Factors in Transcriptome of Chrysanthemum mongolicum and Roles of CmbZIP9 in Drought Stress Resistance.

bZIP transcription factors play important roles in regulating plant development and stress responses. Although bZIPs have been identified in many plant species, there is little information on the bZIPs in Chrysanthemum. In this study, bZIP TFs were identified from the leaf transcriptome of C. mongolicum, a plant naturally tolerant to drought. A total of 28 full-length bZIP family members were identified from the leaf transcriptome of C. mongolicum and were divided into five subfamilies based on their phylogenetic relationships with the bZIPs from Arabidopsis. Ten conserved motifs were detected among the bZIP proteins of C. mongolicum. Subcellular localization assays revealed that most of the CmbZIPs were predicted to be localized in the nucleus. A novel bZIP gene, designated as CmbZIP9, was cloned based on a sequence of the data of the C. mongolicum transcriptome and was overexpressed in tobacco. The results indicated that the overexpression of CmbZIP9 reduced the malondialdehyde (MDA) content and increased the peroxidase (POD) and superoxide dismutase (SOD) activities as well as the expression levels of stress-related genes under drought stress, thus enhancing the drought tolerance of transgenic tobacco lines. These results provide a theoretical basis for further exploring the functions of the bZIP family genes and lay a foundation for stress resistance improvement in chrysanthemums in the future.

The UDP-glycosyltransferase gene OsUGT706E2 negatively regulates rice tolerance to blast disease and abiotic stresses

Despite the crucial role of UDP-glycosyltransferases (UGTs) in various stress responses in plants, their biological functions in rice (Oryza sativa L.) remain poorly understood. In this study, we introduce a novel gene, OsUGT706E2, which is expressed at significantly higher levels in wild rice compared to cultivated rice. OsUGT706E2 is active in multiple tissues and localizes to both the nucleus and cytoplasm. Its transcription is notably up-regulated in response to cold stress, blast disease, and several hormone treatments. Overexpression of OsUGT706E2 markedly reduces seedling tolerance to blast disease, cold, and osmotic stress, whereas knocking out OsUGT706E2 enhances seedling tolerance to blast disease and osmotic stress. The expression levels of stress-related genes in OsUGT706E2 overexpressing plants were significantly lower compared to wild-type plants following stress treatment. Conversely, OsUGT706E2 knockout plants exhibited markedly higher expression levels of these genes than the control plants after stress treatment. Metabolome analysis further indicated that OsUGT760E2 influences metabolite content in rice. Specifically, OsUGT760E2-overexpressing seedlings had higher amino acid content and lower lipid content compared to wild-type seedlings, while OsUGT760E2-knockout seedlings showed lower amino acid content and higher lipid content than control seedlings. These findings suggest that OsUGT760E2 negatively regulates resistance to blast disease as well as tolerance to cold and osmotic stress in rice. As a result, OsUGT760E2 represents a promising target for enhancing rice stress tolerance through gene editing approaches.

Evaluation of the <i>GhMAPK</i> gene expression level under salt stress in cotton cultivars

Background: Abiotic environmental stress factors such as salt stress, drought, oxidative stress adversely affect the development and productivity of plants. To combat adverse environmental conditions, plants have developed a number of protective mechanisms. MAP kinases are protein kinases that regulate cellular activity in response to extracellular stimuli. Given the significant role of MAP kinase mechanisms in universal biological processes, elucidation of its role and mechanisms can be used to create stress-resistant genotypes. The use of stimulators and blockers of MAP kinase mechanisms is promising as a new direction in the management of plant stress resistance. The main goal of the conducted research is the comparative analysis of expression patterns of cotton accessions under salt stress conditions, the study of the relation between an increase in salt concentration and the change in the level of transcripts. Thirteen cultivars from Azerbaijan, nine from Turkey, four from Uzbekistan, four from Greece and one from Kyrgyzstan were used in the research, and changes in the expression level of the GhMAPK gene in cotton accessions was studied with the application of the real-time PCR analysis. In the present study, the evaluation of thirty-one cotton cultivars under different salt stress (NaCl) concentrations revealed significant differences in gene expression levels between cultivars of the same species. The ‘Navai-9’ cultivar from Uzbekistan had the highest expression level at both 100 mM and 200 mM salt concentrations compared to all other cultivars. Among local cultivars, cv. ‘Ganja-110’ (at 100 mM salt concentration), and cv. ‘Zafar’ (at 200 mM) differed from others in the level of changes in transcripts. In addition, there was a wide variation in the expression levels of stress-related genes between groups of accessions identified as resistant and sensitive, and within groups. Thus, both the increase and decrease in the expression level were found within these groups. This diversity in gene expression in sensitive and resistant cultivars in response to the salt stress shows that the mechanisms providing salt tolerance in the studied cultivars are different.

Lacticaseibacillus paracasei AD22 Stress Response in Brined White Cheese Matrix: In Vitro Probiotic Profiles and Molecular Characterization.

Functionalizing foods involve discovering and integrating new candidate health-promoting bacteria into the food matrix. This study aimed (i) to reveal the probiotic potential of autochthonous Lacticaseibacillus paracasei AD22 by a series of in vitro tests and molecular characterization and (ii) to evaluate its application to the matrix of brined white cheese, which is the most common cheese in Türkiye, in terms of survival and stress response. To evaluate in vitro probiotic characteristics, L. paracasei AD22 was exposed to functional, technological, and safety tests. Pilot scale production was conducted to integrate L. paracasei AD22 into the brined white cheese matrix. The expression levels of stress-related genes (dnaK, groES, ftsH, argH, and hsp20) were detected by reverse-transcriptase polymerase chain reaction to determine the transcriptional stress response during ripening. The presence of genes encoding stress-related proteins was determined by whole-genome sequence analysis using a subsystem approach; the presence of antibiotic resistance and virulence genes was determined by ResFinder4.1 and VirulenceFinder 2.0 databases. The BAGEL4 database determined the presence of bacteriocin clusters. L. paracasei AD22 was found to survive in pH 2 and medium with 12% NaCl and did not cause hemolysis. Adhesion of the strain to Caco2 cells was 76.26 ± 4.81% and it had coaggregation/autoaggregation properties. It was determined that L. paracasei AD22 exceeded 7 log cfu/g in the cheese matrix at the end of the ripening period. Total mesophilic aerobes decreased in the cheese inoculated with L. paracasei AD22 after the 45th day of ripening. While hsp20 and groES genes were downregulated during ripening, argH was upregulated. Both downregulation and upregulation were observed in dnaK and ftsH. Fold changes indicating the expression levels of dnaK, groES, ftsH, argH, and hsp20 genes were not statistically significant during ripening (p > 0.05). Whole-genome sequence profiles revealed that the strain did not contain antibiotic and virulence genes but bacteriocin clusters encoding Enterolysin A (Class III bacteriocin), Carnosine CP52 (class II bacteriocin), Enterocin X beta chain (Class IIc bacteriocin), and the LanT region. Subsystems approach manifested that the most functional part of the genomic distribution belonged to metabolism, protein processing, and stress response functions. The study findings highlight that L. paracasei AD22 will provide biotechnological innovation as a probiotic adjunct because it contains tolerance factors and probiotic characteristics to produce new functional foods.

TaWRKY31, a novel WRKY transcription factor in wheat, participates in regulation of plant drought stress tolerance

BackgroundWheat, a crucial food crop in China, is highly vulnerable to drought stress throughout its growth and development. WRKY transcription factors (TFs), being one of the largest families of TFs, play a vital role in responding to various abiotic stresses in plants.ResultsHere, we cloned and characterized the TF TaWRKY31 isolated from wheat. This TF, belonging to the WRKY II family, contains a WRKYGQK amino acid sequence and a C2H2-type zinc finger structure. TaWRKY31 exhibits tissue-specific expression and demonstrates responsiveness to abiotic stresses in wheat. TaWRKY31 protein is localized in the nucleus and can function as a TF with transcription activating activity at the N-terminus. Results showed that the wheat plants with silenced strains (BSMV:TaWRKY31-1as and BSMV:TaWRKY31-2as) exhibited poor growth status and low relative water content when subjected to drought treatment. Moreover, the levels of O2·−, H2O2, and malondialdehyde (MDA) in the BSMV:TaWRKY31-induced wheat plants increased, while the activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) decreased. Compared to control plants, BSMV:TaWRKY31-induced wheat plants exhibited lower expression levels of TaSOD (Fe), TaPOD, TaCAT, TaDREB1, TaP5CS, TaNCED1, TaSnRK2, TaPP2C, and TaPYL5.Under stress or drought treatment conditions, the overexpression of TaWRKY31 in Arabidopsis resulted in decreased levels of H2O2 and MDA, as well as reduced stomatal opening and water loss. Furthermore, an increase in resistance oxidase activity, germination rate, and root length in the TaWRKY31 transgenic Arabidopsis was observed. Lastly, overexpression of TaWRKY31 in Arabidopsis resulted in higher the expression levels of AtNCED3, AtABA2, AtSnRK2.2, AtABI1, AtABF3, AtP5CS1, AtSOD (Cu/Zn), AtPOD, AtCAT, AtRD29A, AtRD29B, and AtDREB2A than in control plants.ConclusionsOur findings indicate that TaWRKY31 enhances drought resistance in plants by promoting the scavenging of reactive oxygen species, reducing stomatal opening, and increasing the expression levels of stress-related genes.

Effects of Clothianidin Pesticide Application on the Strength of Honey Bee Colonies and Stress-Related Genes in the Vicinity of Rice Fields in the Republic of Korea

The honey bee, a crucial organism that provides ecological and economic value to humans, is currently facing threats from various environmental factors including pesticides. Numerous studies have been conducted to demonstrate the risks associated with neonicotinoid pesticides, but research on their occurrence in actual field conditions has not been identified. Therefore, in this study, we observed changes in honey bee (Apis mellifera) colonies located near rice cultivation areas as they progressed beyond the rice pesticide application period. Furthermore, we collected honey bees exposed to the clothianidin and analyzed their stress-related gene expression. The results showed that the foraging behavior of honey bee colonies located near rice cultivation areas did not exhibit significant differences between the treatment sites (Cheongyang and Gimje) and the control site (Wanju) during the experimental period. However, it was observed that the expression levels of stress-related genes in honey bees collected from the treatment group were significantly higher than those in the control. Most of the stress-related genes were associated with detoxification processes in response to pesticides. As a result, pesticide treatment in proximity to rice cultivation areas did not cause direct damage to honey bees but had an indirect impact, suggesting the potential for ongoing chronic damage.

Transcription Factor VvDREB2A from Vitis vinifera Improves Cold Tolerance.

Low temperatures restrict the growth of the grapevine industry. The DREB transcription factors are involved in the abiotic stress response. Here, we isolated the VvDREB2A gene from Vitis vinifera cultivar 'Zuoyouhong' tissue culture seedlings. The full-length VvDREB2A cDNA was 1068 bp, encoding 355 amino acids, which contained an AP2 conserved domain belonging to the AP2 family. Using transient expression in leaves of tobacco, VvDREB2A was localized to the nucleus, and it potentiated transcriptional activity in yeasts. Expression analysis revealed that VvDREB2A was expressed in various grapevine tissues, with the highest expression in leaves. VvDREB2A was induced by cold and the stress-signaling molecules H2S, nitric oxide, and abscisic acid. Furthermore, VvDREB2A-overexpressing Arabidopsis was generated to analyze its function. Under cold stress, the Arabidopsis overexpressing lines exhibited better growth and higher survival rates than the wild type. The content of oxygen free radicals, hydrogen peroxide, and malondialdehyde decreased, and antioxidant enzyme activities were enhanced. The content of raffinose family oligosaccharides (RFO) also increased in the VvDREB2A-overexpressing lines. Moreover, the expression of cold stress-related genes (COR15A, COR27, COR6.6, and RD29A) was also enhanced. Taken together, as a transcription factor, VvDREB2A improves plants resistance to cold stress by scavenging reactive oxygen species, increasing the RFO amount, and inducing cold stress-related gene expression levels.

The combined effects of polyethylene microplastics and benzoanthracene on Manila clam Ruditapes philippinarum

Microplastic (MP) toxicity has recently been explored in various marine species. Along with the toxicity of plastics polymer itself, additional substances or pollutants that are absorbed onto it may also be harmful. In the present study, we investigated the combined impacts of polyethylene microplastics (PE MPs) and an organic pollutant (Benzo(a)anthracene, BaA) on Manila clam Ruditapes philippinarum during a one-week exposure. Two PE MPs concentrations (26 μg L−1 and 260 μg L−1) and one BaA concentration (3 μg L−1) were tested. The clams were exposed to BaA and PE MPs either alone or in combination. BaA and PE MPs were incubated before the combined exposure. The biological effects of PE MPs and BaA on the clams were evaluated by considering several assays such as feeding rate, anti-oxidant enzyme activities, and the expression levels of stress-related genes. The feeding rate significantly decreased in individual PE MPs and individual BaA groups while it remained unchanged in combined groups. Superoxide dismutase (SOD) was the most affected among the biochemical parameters. Malondialdehyde (MDA), and glutathione peroxidase (GPx) activities were slightly affected, whereas no changes were observed in glutathione s-transferase (GST) activities. CYP1A1, CYP3A4, and HSP70 gene expressions displayed slightly significant changes. Considering all stressor groups, high PE MPs exposure (260 μg L−1 PE MPs) more effectively altered the biological parameters in the clams compared to individual low PE MPs and BaA exposure, and their combination. The results also indicated the negligible vector role of PE MPs to transport BaA into the clam tissues.

Comparative transcriptomic analysis and functional characterization reveals that the class III peroxidase gene TaPRX-2A regulates drought stress tolerance in transgenic wheat.

Drought is a major abiotic stress that reduces crop yields and quality worldwide. Although some genes involved in the response to drought stress have been identified, a more in-depth understanding of the mechanisms underlying wheat tolerance to drought is needed for the control of drought tolerance. Here, we evaluated the drought tolerance of 15 wheat cultivars and measured their physiological-biochemical parameters. Our data showed that the drought tolerance of the resistant wheat cultivars was significantly higher than that of drought-sensitive cultivars, which was associated with a greater antioxidant capacity of the former. Transcriptomic analysis revealed that different mechanisms of drought tolerance exist between the wheat cultivars Ziyou 5 and Liangxing 66. Transcriptomic analysis also revealed a large number of DEGs, including those involved in flavonoid biosynthesis, phytohormone signalling, phenolamides and antioxidants. qRT-PCR was performed, and the results showed that the expression levels of TaPRX-2A were significantly different among the various wheat cultivars under drought stress. Further study revealed that overexpression of TaPRX-2A enhanced tolerance to drought stress through the maintenance of increased antioxidase activities and reductions in ROS contents. Overexpression of TaPRX-2A also increased the expression levels of stress-related genes and ABA-related genes. Taken together, our findings show that flavonoids, phytohormones, phenolamides and antioxidants are involved in the plant response to drought stress and that TaPRX-2A is a positive regulator of this response. Our study provides insights into tolerance mechanisms and highlights the potential of TaPRX-2A overexpression in enhancing drought tolerance in crop improvement programmes.

Exogenous hydrogen sulfide and methylglyoxal alleviate cadmium-induced oxidative stress in Salix matsudana Koidz by regulating glutathione metabolism

BackgroundCadmium (Cd) is a highly toxic element for plant growth. In plants, hydrogen sulfide (H2S) and methylglyoxal (MG) have emerged as vital signaling molecules that regulate plant growth processes under Cd stress. However, the effects of sodium hydrosulfide (NaHS, a donor of H2S) and MG on Cd uptake, physiological responses, and gene expression patterns of Salix to Cd toxicity have been poorly understood. Here, Salix matsudana Koidz. seedlings were planted in plastic pot with applications of MG (108 mg kg− 1) and NaHS (50 mg kg− 1) under Cd (150 mg kg− 1) stress.ResultsCd treatment significantly increased the reactive oxygen species (ROS) levels and malondialdehyde (MDA) content, but decreased the growth parameters in S. matsudana. However, NaHS and MG supplementation significantly decreased Cd concentration, ROS levels, and MDA content, and finally enhanced the growth parameters. Cd stress accelerated the activities of antioxidative enzymes and the relative expression levels of stress-related genes, which were further improved by NaHS and MG supplementation. However, the activities of monodehydroascorbate reductase (MDHAR), and dehydroascorbate reductase (DHAR) were sharply decreased under Cd stress. Conversely, NaHS and MG applications restored the MDHAR and DHAR activities compared with Cd-treated seedlings. Furthermore, Cd stress decreased the ratios of GSH/GSSG and AsA/DHA but considerably increased the H2S and MG levels and glyoxalase I-II system in S. matsudana, while the applications of MG and NaHS restored the redox status of AsA and GSH and further improved glyoxalase II activity. In addition, compared with AsA, GSH showed a more sensitive response to exogenous applications of MG and NaHS and plays more important role in the detoxification of Cd.ConclusionsThe present study illustrated the crucial roles of H2S and MG in reducing ROS-mediated oxidative damage to S. matsudana and revealed the vital role of GSH metabolism in regulating Cd-induced stress.

Dietary Protein Levels Modulate the Antioxidant Capacity during Different Growth Stages in Huanjiang Mini-Pigs.

Adequate crude protein (CP) levels in diets play potential roles in swine production. This study determined the impacts of different CP levels on the antioxidant capacity of pigs during different body weight (BW) stages. Three hundred and sixty Huanjiang mini-pigs were allocated to one of three independent experiments, including a 5-10 kg BW group, where CP levels included 14%, 16%, 18%, 20%, and 22%; a 10-20 kg BW group, where CP levels included 12%, 14%, 16%, 18%, and 20%; and a 20-30 kg BW group, where CP levels included 10%, 12%, 14%, 16%, and 18%. These independent experiments were conducted for 28, 28, and 26 days, respectively. Results showed that the 20% CP level increased (p < 0.05) the plasma CAT and GSH-Px activities and the GSH concentration of pigs than in the pigs supplemented with the 14-18% CP levels, and the 20% CP level up-regulated (p < 0.05) the ileal oxidative stress-related gene expression levels of pigs than in the pigs supplemented with the 14% CP level at the 5-10 kg BW. In addition, diets supplemented with 18% CP level increased (p < 0.05) the ileal GSH concentration of pigs than in the pigs supplemented with the 14% and 20% CP levels, and the 16-18% CP levels increased (p < 0.05) the jejunal SOD activity of pigs than in the pigs supplemented with the 14% CP level. At 10-20 kg BW, the 16% CP level presented the strongest jejunal and ileal antioxidant capacity, the 18% CP level had the lowest plasma concentrations of MDA and highest GSH, and the 14-16% CP levels increased the plasma CAT and SOD activities (p < 0.05). Moreover, the 16-20% CP levels up-regulated (p < 0.05) the oxidative stress-related gene expression levels. At 20-30 kg BW, diets supplemented with the 16% CP level increased the plasma CAT activity of pigs than in the pigs supplemented with the 12-14% CP levels, and the 14-16% CP levels decreased the MDA concentration compared with the 10% CP levels (p < 0.05). In conclusion, these findings indicate adequate CP levels of 20%, 16%, and 14% for Huanjiang mini-pigs at the 5-10, 10-20, and 20-30 kg BW stages, respectively.

AtVIP1 AND GsNAC2 ENHANCE SALINE-ALKALI STRESS TOLERANCE BY PROMOTING PLANT GROWTH AND INDUCING STRESS RESPONSE GENE DURING THE GERMINATION PERIOD OF SORGHUM

The quality and yields of Sorghum bicolor (L.) plants are seriously affected by saline-alkali conditions. VIP, and NAC (NAM, ATAF, and CUC) transcription factors are specific, and have various functions in plant development and response to various stresses. To study the tolerance to saline-alkali stress of transgenic sorghum overexpressed by AtVIP1 and GsNAC2 genes, sorghum seeds were treated with stress solution (NaHCO3: Na2CO3 = 5: 1, 75 mM, pH 9.63). After the stress treatment, the growth morphological indexes, stress-resistant physiological indexes and stress-related gene expression levels of sorghum buds were measured. The results show that the transgenic sorghum with overexpressing AtVIP1 and GsNAC2 genes had a higher bud length, fresh weight, and moisture content. Compared to the control, lower H2O2 and O2- levels, relative permeability of the plasma membrane, and MDA content, with higher POD, CAT, and SOD activities were found in transgenic sorghum. Gene expression analysis revealed that several stress response genes were up-regulated. Furthermore, these results suggest that AtVIP1 and GsNAC2 gene play potentially important roles in response to saline-alkali stress, and may be used in breeding new varieties to improve sorghum yields under adverse environmental conditions.

염분 변화에 따른 명태(Gadus Chalcogrammus)의 스트레스 반응; 혈액생리학적 변화 및 유전자 발현

The study evaluated the change of stress indicators in plasma and mRNA expression levels of stress-related genes in head-kidney and liver of walleye pollock, Gadus chalcogrammus according to acute salinity fluctuation. Walleye pollocks were exposed for 24 hours in five groups, as salinity are 34, 30, 25, 20, and 15 psu. The levels of hematocrit (Ht), glutamic oxaloacetate transaminase (GOT), cortisol, glucose, and superoxide dismutase (SOD) in plasma were increased as the salinity of the breeding water decreased. Ht increased with 37.5 ± 1% at 20 psu. GOT with 41.0 ± 5.03 U/L, cortisol with 882.73 ± 32.73 ng/mL, and glucose with 67.67±11.6 ng/dL increased a significant difference at 25 psu. The SOD activity levels in plasma were highest at 15 psu with 3.51 ± 0.13 U/mL. Plasma hemoglobin (Hb) and glutamic pyruvic transaminase (GPT) did not show a statistically significant difference according to salinity, but showed a tendency to increase as the salinity decreased. Total protein (TP) levels in plasma were the highest with 5.9 ± 0.61 g/dL at 25 psu. The relative mRNA expression of stress-related genes was investigated in the head-kidney and liver of walleye pollocks, and the mRNA expression of steroidogenic acute regulatory protein (StAR) and heat shock protein 70 (HSP70) increased, as the salinity decreased from 25 psu, whereas glucocorticoid receptor (GR) mRNA expression decreased as the salinity decreased. These results suggest that walleye pollocks become stressed-condition to salinity below 25 psu, but homeostasis can be maintained up to 15 psu in short-term.

Identification of Peanut AhMYB44 Transcription Factors and Their Multiple Roles in Drought Stress Responses.

MYB transcription factors (TFs) comprise a large gene family that plays an important role in plant growth, development, stress responses, and defense regulation. However, their functions in peanut remain to be further elucidated. Here, we identified six AhMYB44 genes (AhMYB44-01/11, AhMYB44-05/15, and AhMYB44-06/16) in cultivated peanut. They are typical R2R3-MYB TFs and have many similarities but different expression patterns in response to drought stress, suggesting different functions under drought stress. Homologous genes with higher expression in each pair were selected for further study. All of them were nuclear proteins and had no self-transactivation activity. In addition, we compared the performances of different lines at germination, seedling, and adult stages under drought stress. After drought treatment, the overexpression of AhMYB44-11 transgenic plants resulted in the longest root length at the seedling stage. Levels of proline, soluble sugar and chlorophyll, and expression levels of stress-related genes, including P5CS1, RD29A, CBF1, and COR15A, were higher than those of the wild type (WT) at the adult stage. While the overexpression of AhMYB44-16 significantly increased the drought sensitivity of plants at all stages, with differential ABA content, the expression levels of the ABA-related genes PP2CA and ABI1 were significantly upregulated and those of ABA1 and ABA2 were significantly downregulated compared with the WT. AhMYB44-05 showed similar downregulated expression as AhMYB44-16 under drought stress, but its overexpression in Arabidopsis did not significantly affect the drought resistance of transgenic plants. Based on the results, we propose that AhMYB44-11 plays a role as a positive factor in drought tolerance by increasing the transcription abundance of stress-related genes and the accumulation of osmolytes, while AhMYB44-16 negatively regulates drought tolerance through its involvement in ABA-dependent stress response pathways.

A Group I WRKY Gene, TaWRKY133, Negatively Regulates Drought Resistance in Transgenic Plants.

WRKYs are one of the largest transcription factor (TF) families and play an important role in plant resistance to various stresses. TaWRKY133, a group I WRKY protein, responds to a variety of abiotic stresses, including PEG treatment. The TaWRKY133 protein is located in the nucleus of tobacco epidermal cells, and both its N-terminal and C-terminal domains exhibit transcriptional activation activity. Overexpression of TaWRKY133 reduced drought tolerance in Arabidopsis thaliana, as reflected by a lower germination rate, shorter roots, higher stomatal aperture, poorer growth and lower antioxidant enzyme activities under drought treatment. Moreover, expression levels of stress-related genes (DREB2A, RD29A, RD29B, ABF1, ABA2, ABI1, SOD (Cu/Zn), POD1 and CAT1) were downregulated in transgenic Arabidopsis under drought stress. Gene silencing of TaWRKY133 enhanced the drought tolerance of wheat, as reflected in better growth, higher antioxidant enzyme activities, and higher expression levels of stress-related genes including DREB1, DREB3, ABF, ERF3, SOD (Fe), POD, CAT and P5CS. In conclusion, these results suggest that TaWRKY133 might reduce drought tolerance in plants by regulating the expression of stress-related genes.

Heterologous Overexpression of ZmHDZIV13 Enhanced Drought and Salt Tolerance in Arabidopsis and Tobacco

The homeodomain leucine zipper (HD-Zip) IV transcription factor is indispensable in the response of plants to abiotic stress. Systematic studies have been carried out in Arabidopsis, rice and other species from which a series of stress resistance-related genes have been isolated. However, the function of the HD-Zip IV protein in maize is not clear. In this study, we cloned the HD-Zip IV gene ZmHDZIV13 and identified its function in the stress response. Our phylogenetic analysis showed that ZmHDZIV13 and AtHDG11 had high homology and might have similar functions. The heterologous overexpression of ZmHDZIV13 in Arabidopsis resulted in sensitivity to abscisic acid (ABA), salt tolerance during germination and drought tolerance in seedlings. Under drought stress, the transgenic Arabidopsis showed stronger drought resistance than the wild-type (control). The malondialdehyde content of ZmHDZIV13 transgenic plants was lower than that of the control, and the relative water content and proline content were significantly higher than those of the control. After the drought was relieved, the expression levels of stress-related genes were up-regulated in transgenic Arabidopsis. These results show that ZmHDZIV13, as a stress-responsive transcription factor, plays a role in the positive regulation of abiotic stress tolerance and can regulate an ABA-dependent signaling pathway to regulate drought response in plants.

Response of soybean (Glycine max L.) seedlings to polystyrene nanoplastics: Physiological, biochemical, and molecular perspectives

Micro and nanoplastics are new generation contaminants of global concern. It is important to evaluate the effects on edible products due to the presence of micro- and nano-sized plastics in the treated wastewater. A hydroponic experiment was carried out to explore the effect of polsytrene nanoplastics (PS-NPs; 20 nm) at different concentrations (0, 12.5, 25, and 50 mg L−1) on Glycine max L. (soybean) seedlings for 7-days. In the current study, firstly the uptake of PS-NPs by Glycine max L. (soybean) roots were confirmed by laser confocal scanning microscope. Exposure to PS-NPs, negatively affected growth parameters and increased Fe, Zn and Mn contents in roots and leaves of soybean seedlings. PS-NPs treatments caused oxidative stress in soybean seedlings. The hydrogen peroxide and malondialdehyde contents, showed similar increase pattern in seedlings exposed to PS-NPs. Response to PS-NPs, the level of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase, and guaiacol peroxidase) and proline content were generally enhanced in roots and leaves of soybean. The expression level of stress-related genes examined in the study included CSD5, FSD3, APX1, and POD up-regulated in PS-NPs treated-soybean seedlings in a tissue specific manner. The results of the present study showed the adverse effects of PS-NPs on soybean seedlings, which may have important implications for the risk assessment of NPs on crop production and environmental safety.

Integrated transcriptome and metabolome analyses reveal the adaptation of Antarctic moss Pohlia nutans to drought stress.

Most regions of the Antarctic continent are experiencing increased dryness due to global climate change. Mosses and lichens are the dominant vegetation of the ice-free areas of Antarctica. However, the molecular mechanisms of these Antarctic plants adapting to drought stress are less documented. Here, transcriptome and metabolome analyses were employed to reveal the responses of an Antarctic moss (Pohlia nutans subsp. LIU) to drought stress. We found that drought stress made the gametophytes turn yellow and curled, and enhanced the contents of malondialdehyde and proline, and the activities of antioxidant enzymes. Totally, 2,451 differentially expressed genes (DEGs) were uncovered under drought treatment. The representative DEGs are mainly involved in ROS-scavenging and detoxification, flavonoid metabolism pathway, plant hormone signaling pathway, lipids metabolism pathway, transcription factors and signal-related genes. Meanwhile, a total of 354 differentially changed metabolites (DCMs) were detected in the metabolome analysis. Flavonoids and lipids were the most abundant metabolites and they accounted for 41.53% of the significantly changed metabolites. In addition, integrated transcriptome and metabolome analyses revealed co-expression patterns of flavonoid and long-chain fatty acid biosynthesis genes and their metabolites. Finally, qPCR analysis demonstrated that the expression levels of stress-related genes were significantly increased. These genes included those involved in ABA signaling pathway (NCED3, PP2C, PYL, and SnAK2), jasmonate signaling pathway (AOC, AOS, JAZ, and OPR), flavonoid pathway (CHS, F3’,5’H, F3H, FLS, FNS, and UFGT), antioxidant and detoxifying functions (POD, GSH-Px, Prx and DTX), and transcription factors (ERF and DREB). In summary, we speculated that P. nutans were highly dependent on ABA and jasmonate signaling pathways, ROS scavenging, flavonoids and fatty acid metabolism in response to drought stress. These findings present an important knowledge for assessing the impact of coastal climate change on Antarctic basal plants.