PEG Treatment Research Articles

Morphophysiological Response of Peranggi Chili (Capsicum annum L. var chinensis) to Drought Stress

Peranggi chili (Capsicum annum L. var chinensis) is a red chili that has a spicy taste. Peranggi chili is not widely known by the community and has not been widely studied. In addition, peranggi chili is very easily exposed to drought so its growth is easily disrupted. This study aimed to determine morphophysiology of peranggi chili with PEG treatment as drought stress with concentrations of 0%, 10%, 20%, and 30%. This research was conducted from June to November 2024. The study used an experimental method with a completely randomized design (CRD) to test the growth of peranggi chili with PEG 6000 treatment as drought stress with concentrations of 0%, 10%, 20%, and 30%. The treatment was given after the chili grew 30 days after transfer (DAT). Measurements were taken at 40, 50, 60, and 70 DAT. The results showed that the morphology of peranggi chili plants was not affected by different concentrations of PEG 6000 except root length which decreased significantly at 70 DAT. The shoot: root fresh and dry weight ratio decreased until 50 DAT and reduce slowly until 70 DAT. Similarly, physiological measurements in the form of chlorophyll a, b, and total content decreased from 50 to 70 DAT, but the treatment level had a different impact. From this study, the effect of drought stress using PEG 6000 0%, 10%, 20%, and 30% began to affect the vegetative growth of peranggi chili peppers at 50 DAT.

The impact of primers for wood bonding on beech wood’s Young’s modulus

When producing load-bearing timber products with one-component polyurethane adhesives and certain wood species, e.g., beech or larch, primers can be used to obtain stronger and more durable bonds. The active chemicals of three existing primer systems, hydroxymethylated resorcinol formaldehyde (HMR), polysorbate 20 (PS20), and poly(ethylene glycol) (PEG), were used to impregnate beech wood. Young’s modulus (E) in the radial direction was determined in tensile mode. A modified E can influence the deformation and stress distribution at the wood-glue interface. Compared to the untreated wood, the average E was reduced by 7% for the water-treated reference and the HMR treatment. With the PS20 treatment, the average E was reduced by 16%, compared to the untreated wood, and by 45% with the PEG treatment.

Assessment Of Drought Tolerance in Different Rice Genotypes During Germination and Early Growth Stages by Using Polyethylene Glycol-6000

Rice is a crucial staple food for over half of the global population, particularly in Southeast Asia. However, rice production is increasingly affected by biotic and abiotic stresses, including drought, exacerbated by global climate change. This study explored the effects of negative osmotic pressure induced by polyethylene glycol (PEG-6000) on rice seed germination and growth traits. The experiment was conducted at Gokuleshwor Agriculture and Animal Science College Laboratory, Baitadi, Nepal, using four rice varieties: Black rice, Subha mansuli, Hardinath-4, and Rato basmati. Four osmotic potentials (0, -0.2, -0.4, -0.6 MPa) were applied under controlled conditions. Data on seed germination, root length, shoot length, root-to-shoot ratio, and vigor index were analyzed using two-way ANOVA and LSD tests. Results showed significant differences among rice genotypes and PEG treatments. Rato basmati exhibited the highest germination percentage (78.27%), root length (4.44 cm), shoot length (4.44 cm), and vigor index (718.78), even at -0.6 MPa osmotic potential, indicating superior drought tolerance. Increasing PEG-induced osmotic stress reduced germination and seedling growth across all genotypes. However, Rato basmati’s better performance under -0.6 MPa suggests it as a drought-tolerant genotype, making it a potential candidate for future drought-tolerance breeding programs in rice. Int. J. Appl. Sci. Biotechnol. Vol 12(4): 194-200.

Genetic Diversity and Drought Stress Tolerance of a Global Collection of Pearl Millet at Germination and Early Seedling Growth Stages.

Pearl millet {Pennisetum glaucum (L.) R. Br} is a C4 panicoid cereal millet crop grown in arid and semi-arid regions in Africa and Asia for food and fodder. This study involves the evaluation of the genetic diversity of 28 worldwide germplasm collection of pearl millet by genetic markers polymorphism and drought tolerance indices. The genetic diversity was expressed by 51 alleles of 9ISSR markers that showed 96.43% totalpolymorphism and 11.76 alleles per marker. Cluster analysis of ISSR markers polymorphism divided the 28 genotypes into four clusters partially in agreement with their origin. The application of drought stress simulated by 20% PEG6000 treatment, retarded the germination percentage, and reduced shoot and root length, seedling fresh and dry weights. Drought tolerance indices (DTIs) were calculated based on the response of the seedling traits under drought stress compared to the control seedlings. ANOVA revealed statistically significant variation among the genotypes (P ≤ 0.05), except for seedling fresh weight (P = 0.17 > 0.05) under control conditions and seedling dry weight (P = 0.99 > 0.05) under drought conditions. Genotypes having higher DTIs for three traits are regarded drought resistant, i.e., those from India, Ethiopia, Pakistan, and Nigeria. The calculated heritability values indicated that seedlings dry weight is the least trait affected by drought stress whereas root length is the most influenced trait. Hierarchical clustering, based on the DTI values, also grouped the genotypes partially concomitant to their origin. The correlation analysis demonstrated a modest positive correlation between shoot length and root length. A low correlation of r ≤ 0.12 was observed between the morphological DTI matrix and the genetic matrix. Nevertheless, high levels of genetic diversity were identified among the examined genotypes that may face genetic erosion by climatic constraints, and a high potential for creating agronomically superior cultivars by crossing widely divergent genotypes.

Systematic identification of sugarcane vacuolar H+-translocating pyrophosphatase (VPP) gene family and the role of ScVPP1 in salt resistance.

A total of 24 genes of vacuolar H+-translocating pyrophosphatases H+-PPases (VPP) genes were identified in Saccharum spontaneum AP85-441 and the ScVPP1-overexpressed Arabidopsis plants conferred salt tolerance. The vital role of vacuolar H+-translocating pyrophosphatases H+-PPases (VPP) genes involved in plants in response to abiotic stresses. However, the understanding of VPP functions in sugarcane remained unclear. In this study, a total of 24 VPP genes (SsaVPP1-SsaVPP24) were identified in the Saccharum spontaneum genome of haploid clone AP85-441. These genes were distributed in two phylogenetic groups. The SsaVPPs displayed diverse physio-chemical and gene structure attributes. The SsaVPP family genes have expanded through segmental duplication (20 gene pairs) rather than tandem duplication. A full-length cDNA of ScVPP1 was cloned from the sugarcane cultivar ROC22 and shared 99.48% sequence identity (amino acid) with homologous gene SsaVPP21 from AP85-441. In ROC22, the ScVPP1 gene was considerably upregulated by NaCl and ABA treatments among leaf, root, and stem tissues, while this gene was exclusively upregulated in the root with PEG treatment. Under NaCl and ABA stresses, yeast cells transfected by the ScVPP1 plasmid showed distinct growth rates compared to control yeast cells transfected by the empty vector. In transgenic Arabidopsis lines overexpressing ScVPP1, the seed gemination and survival rate were enhanced under NaCl treatment but not underABA stress as compared to wild-type plants. These results suggested that the ScVPP1 gene conferred tolerance to slat and may be used as a salt resistance gene source for sugarcane breeding.

Genome-wide analysis of the cotton COBRA-like gene family and functional characterization of GhCOBL22 in relation to drought tolerance

Abstract Background The COBRA-like (COBL) gene family is a crucial glycosylphosphatidylinositol (GPI)-anchored proteins that participate in various biological processes in plants by regulating the arrangement of cell wall microfibrils. While the functions of COBL genes have been analyzed in several plant species, their roles in cotton’s response to abiotic stress remain unexplored. Results This study identified and characterized the COBL gene family in Gossypium hirsutum, revealing a total of 39 COBL family members classified into five subgroups. Transcriptome analysis indicated that the transcription levels of several GhCOBL genes were upregulated following PEG treatment, with GhCOBL22 being significantly induced. Further silencing of the GhCOBL22 gene through virus-induced gene silencing (VIGS) technology demonstrated that this gene’s silencing reduced cotton’s drought stress tolerance. Under drought stress conditions, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) enzymes, along with proline (PRO) content, were lower in GhCOBL22-silenced plants compared to control plants, while the accumulation of malondialdehyde (MDA) was significantly higher. Moreover, silencing the GhCOBL22 gene also led to reductions in the levels of cellulose, hemicellulose, and lignin content in cotton leaves. Conclusion A systematic survey of gene structure, motif composition, and evolutionary relationships of the COBL gene family was conducted in Gossypium hirsutum. Subsequent expression and functional studies indicated that GhCOBL22 plays a significant role in cotton’s drought tolerance. These findings enhance our understanding of the biological functions of the COBL family and highlight the critical role of the GhCOBL22 gene in cotton’s response to drought stress.

Genome-Wide Analysis of the PYL Gene Family in Betula platyphylla and Its Responses to Abiotic Stresses.

Abscisic acid (ABA) is a key phytohormone that participates in various plant biological processes, such as seed germination, senescence, stomatal movement, and flowering. In the ABA signal transduction pathway, Pyrabactin Resistance 1 (PYR1)/PYR1-Like (PYL)/Regulatory Component is the core module for ABA perception. In this study, a total of 12 PYL family members were identified in birch (Betula platyphylla Suk.) from a genome-wide range that can be divided into 3 subgroups according to their evolutionary relationships. The physiochemical properties of the 12 BpPYLs were characterized, and the members of the same subgroups share more similar exon-intron and motif patterns. The results of synteny analysis showed two syntenic gene pairs within BpPYL family members and 12, 8, 19, and 6 syntenic gene pairs between BpPYLs and AtPYLs, OsPYLs, PtPYLs, and ZmPYLs, respectively. Multiple cis-acting elements were identified in the promoters of BpPYLs, including stress response, phytohormone signaling, and growth and development. The results of GO and KEGG enrichment analysis showed that BpPYLs were enriched in the pathways mainly related to ABA signaling and cell communication. The results of RT-qPCR verified the expressional responses of BpPYLs to ABA, salt, and PEG treatments. Furthermore, the positive roles of BpPYL3 and BpPYL11 were proven by using salt-tolerant yeast transformation. This study provides a reference for research on ABA signal transduction and forest tree responses upon abiotic stresses.

Genome-wide identification of the eggplant jasmonate ZIM-domain (JAZ) gene family and functional characterization of SmJAZ10 in modulating chlorophyll synthesis in leaves.

The jasmonate ZIM-domain (JAZ) plays a crucial role in regulating several economic traits in crops. Despite its importance, the characterization of the SmJAZ gene family in eggplant (Solanum melongena L.) has not been documented. In this study, we identified 13 SmJAZ distributed across 9 chromosomes, which were categorized into 5subgroups based on phylogenetic analysis. Both of them possess TIFY-motif and CCT_2 domains with varying degrees of variation. Promoter cis-element analysis predicted 42 distributed cis-elements that respond to diverse signals. Gene expression analysis demonstrated that SmJAZ exhibited responsiveness to JA, ABA, NaCl, PEG, 4°C, blue light, and UV-B treatments. Moreover, microRNA interaction predictions identified 150 potential miRNAs, among which ath-miR5021 was found to target 8 SmJAZ mRNAs. Yeast two-hybrid assays demonstrated that most of the SmJAZs were able to interact with SmMYC2 and SmNINJA and could form JAZ-JAZ complexes. Subcellular localization analysis unveiled a diverse array of intranuclear and extranuclear localization signals for SmJAZs. Overexpressing of SmJAZ10 could decrease the chlorophyll content of seedling leaves, and the transcriptome showed that genes related to chlorophyll synthesis, such as SmCHLH, SmPORA, and SmGLK2, underwent down-regulated expression. Overall, these findings serve as a valuable resource for leveraging JA signaling to enhance eggplant quality.

The PHD transcription factor ThPHD5 regulates antioxidant enzyme activity to increase salt tolerance in Tamarix hispida

PHD proteins are an important class of transcription factors (TFs) that are widely distributed in eukaryotes and play crucial roles in many aspects of plant growth, development and response to stress. We identified a transcription factor, ThPHD5, from the PHD family in Tamarix hispida based on its potential involvement in abiotic stress response processes. In this study, the salt tolerance function of ThPHD5 from T. hispida was further characterized. The qRT-PCR results showed ThPHD5 expression was significantly induced by NaCl, PEG and ABA treatments. Transient transformation analysis revealed that ThPHD5 improved salt tolerance in T. hispida by increasing POD and SOD activity, decreasing the MDA, total ROS content and electrolyte leakage. To explore the salt tolerance mechanism of the ThPHD5 TF, its binding DNA motifs and potential downstream regulatory genes were analyzed. The results showed that ThPHD5 affect the expression of 7 antioxidant enzyme-related genes. The Yeast one-hybrid (Y1H) and Electrophoretic Mobility Shift Assay (EMSA) results indicated ThPHD5 could bind to ABRE, MYB and Dof cis-acting elements. ChIP-PCR further confirmed ThPHD5 exercise its regulatory function by directly binding motifs on the ThPOD16, ThSOD and ThSOD1 promoters. Taken together, these findings indicate the ThPHD5 TF improves salt tolerance in T. hispida by regulating the expression of antioxidant enzyme-related genes to increase antioxidant enzyme activity, enhance the ROS scavenge ability, reduce ROS accumulation and cellular damage.

Expression analysis of CsNAC30 gene in cucumber under drought stress

This study performed a bioinformatics analysis of the CsNAC30 gene and examined its expression levels in cucumber leaves and roots under drought stress induced by PEG-6000. The bioinformatics analysis showed that the open reading frame (ORF) of CsNAC30 is 1254 bp, encoding a protein consisting of 417 amino acids. This protein is relatively unstable and hydrophilic, lacks transmembrane regions, and contains 49 phosphorylation sites. It also features a conserved NAM domain at the N-terminus. Homology and phylogenetic analyses indicate that CsNAC30 is a member of the NAC transcription factor family and is most closely related to the melon CMeNAC105 and the winter melon BhNAC96. Quantitative real-time PCR (qPCR) revealed that CsNAC30 expression is induced by drought stress, with relative levels increasing in both leaves and roots following PEG treatment. Expression peaked at 6 h in leaves and 9 h in roots before decreasing. These findings suggest that CsNAC30 plays a role in the cucumber’s response to drought stress.

Epigenomic studies in sorghum reveal differential enrichment of multiple histone marks at clade A PP2C genes in response to drought

Epigenetic regulation is essential for plant development and stress responses, as numerous stress-responsive genes are modulated epigenetically. However, most research has focused on individual histone marks. This study expands on previous work by examining the genome-wide profiles of seven histone marks (H3K9ac, H3K27ac, H3K4me3, H3K36me3, H3K27me3, H2A.Z, and H3K4me2) in sorghum leaves and roots under PEG-induced drought stress. Results revealed that five histone marks (excluding H3K36me3 and H3K27me3) were significantly associated with drought-responsive gene expression. The differential enrichment of these marks may enhance the induction of drought-responsive genes. Specifically, a subset of genes showed multiple histone marks' differential enrichment, with most clade A PP2C genes exhibiting enrichment for four marks after PEG treatment. This suggests a critical role for robust PP2C gene induction in sorghum’s drought response. Additionally, promoter cis-element analysis identified ERF family transcription factors as potential mediators of histone mark enrichment under drought conditions, providing new insights into the interaction between epigenetic modifications and transcriptional regulation in plant stress responses.

Genome-wide identification and expression analysis of CASPL gene family in Zea mays (L.).

Casparian strip membrane domain proteins like (CASPL), exhibit profound associations with root development, stress responsiveness and mineral element uptake in plants. Nonetheless, a comprehensive bioinformatics analysis of the ZmCASPL gene family in maize remains unreported. In the study, we have identified 47 ZmCASPL members at the whole-genome level, systematically classifying them into six distinct groups. Furthermore, our analysis revealed that the same group of ZmCASPL contains similar gene structures and conserved motifs. Duplication events showed whole genome duplication (WGD) and tandem duplication (TD) contribute to the generation of the ZmCASPL gene family together in maize, but the former plays a more prominent role. Furthermore, we observed that most ZmCASPL genes contain MYB-binding sites (CAACCA), which are associated with the Casparian strip. Utilizing RNA-seq data, we found that ZmCASPL21 and ZmCASPL47 are specifically highly expressed only in the roots. This finding implies that ZmCASPL21 and ZmCASPL47 may be involved in the Casparian strip development. Additionally, RNA-seq analysis illuminated that drought, salt, heat, cold stresses, low nitrogen and phosphorus conditions, as well as pathogen infection, significantly impact the expression patterns of ZmCASPL genes. RT-qPCR revealed that ZmCASPL 5/13/25/44 genes showed different expression patterns under PEG and NaCl treatments. Collectively, these findings provide a robust theoretical foundation for further investigations into the functional roles of the ZmCASPL gene family in maize.

Comparative analysis of the NF-Y transcription factor family identifies VaNF-YA6 as a positive regulator of salt and drought tolerance in grapevine

Nuclear factor Y transcription factors (NF-Y TFs) play crucial roles in plant responses to abiotic stress. However, there is a lack of research on the comparative analysis of evolutionary relationships, real-time quantitative fluorescence PCR (RT-qPCR), and functions of NF-Y TFs to screen key NF-Y TFs that are resistant to salt and drought stresses between Vitis vinifera (V. vinifera) and Vitis amurensis (V. amurensis). In this study, 27 and 26 NF-Y TFs were identified in V. vinifera and V. amurensis, respectively, and were divided into three subgroups. Subcellular localization prediction revealed that NF-Ys TFs were mainly located in the nucleus. Interestingly, the NF-YA protein sequence of ‘NTKKLDWEFWGCCDDCEKWFGGCC’ was lost in the V. vinifera compared to V. amurensis, whereas the sequence ‘SSVYSQPWWGHSIVCVA’ was gained, thus, these sequences might be closely related to the functions performed. RT-qPCR analysis of ‘Pinot Noir’ (cultivated variety) and ‘Zuoyouhong’ (wild variety) plantlets demonstrated that the expression levels of VaNF-YA6, VaNF-YB5, VvNF-YA3, VvNF-YA5, and VvNF-YC2 were significantly upregulated under 400 mmol·L-1 NaCl and 10% PEG treatments for 24 h Subcellular localization showed that the VaNF-YA6-GFP fusion protein was functioned primarily in the nucleus. Overexpression of VaNF-YA6 in grapevine leaves and Arabidopsis thaliana (Arabidopsis) could significantly enhance tolerance to salt and drought stresses by improving VvSOS2, VvSOS3, VvABF3, VvCPK6 expression levels, enzyme activities, and other protective substances. In summary, our study provides a theoretical basis for the further use of VaNF-YA6 to improve salt and drought resistance in grapevines.

The synergistic potential of polyethylene glycol 400 for the control of Hyphantria cunea larvae by Beauveria bassiana

The efficacy of entomopathogenic fungi as pest control agents is constrained by both their physiological state and external environmental factors. This study identified synergists capable of enhancing the insecticidal activity of Beauveria bassiana (Bb) and investigated the underlying synergistic mechanisms. Our results found that among 6 potential synergists, polyethylene glycol 400 (PEG) and trehalose significantly improved Bb's lethality against Hyphantria cunea larvae, with PEG demonstrating the most pronounced effect. PEG treatment markedly increased Bb spore adhesion and germination rates, while spore hydrophobicity and growth rates remained unaffected. Moreover, PEG-treated spores exhibited higher thermal tolerance compared to untreated ones. In the Bb + PEG treatment group, the hemocyte count, encapsulation and melanization activities, and the expression of related regulatory genes were significantly lower than those in the Bb treatment group. Additionally, pathogen recognition, signal transduction, and humoral immunity effector genes expression were markedly suppressed in the Bb + PEG group. A significant reduction in the content of total amino acids, free fatty acids, glucose, and trehalose, alongside decreased expression of key regulatory genes in the tricarboxylic acid cycle and glycolysis pathways, was observed in the Bb + PEG treatment group. Furthermore, PEG enhanced Bb-induced apoptosis in H. cunea larvae, as evidenced by the upregulation of apoptosis-related genes. Notably, PEG alone did not significantly impact the innate immunity, energy metabolism, or apoptosis in H. cunea larvae. Overall, PEG exhibits considerable potential in amplifying Bb's insecticidal activity by directly optimizing spore performance and indirectly modulating the larvae's innate immunity, energy metabolism, and apoptosis.

Comprehensive characterization of gibberellin oxidase gene family in Brassica napus reveals BnGA2ox15 involved in hormone signaling and response to drought stress

Brassica napus is a well-known allopolyploid oil crop with high commercial potential. Gibberellin oxidase (GAox) is an essential enzyme that activates gibberellins, which regulate plant growth, and development, and have a significant impact on plant responses to abiotic stress. However, the comprehensive understanding of GAox genes and their evolution in Brassica plants remains elusive. Using advanced bioinformatics tools, this study identified 125 candidate GAox genes from the whole genomes of three key Brassica species. This study also investigated sequence characteristics, conserved motifs, exon/intron structures, cis-acting elements, syntenic analysis, duplication events and expression patterns. Subcellular localization analysis showed that the BnGA2ox14 and BnGA2ox15 proteins are located in the nucleus, whereas BnGA2ox26 is specifically localized to the chloroplast. Yeast one-hybrid and dual-luciferase assays demonstrated that MYELOCYTOMATOSIS 4 (BnMYC4) and ABA-INDUCIBLE BHLH-TYPE TRANSCRIPTION FACTOR (BnAIB) bind to the BnGA2ox15 promoter and activate its transcription. Molecular docking analysis further elucidated their interaction structures and identified potential binding sites. Roots transformations show that overexpression of BnGA2ox15 increased sensitivity to PEG-6000 treatment in rapeseed. In brief, this study reveals that BnGA2ox15 is a downstream target in JA and ABA signaling pathways, functioning as a negative regulator in response to drought stress.

Determination of the effects of drought stress on Aronia melanocarpa cv. Nero in vitro conditions

Drought stress is a significant threat to plant cultivation in arid and semi-arid regions, negatively affecting growth and leading to plant mortality. This study evaluated the in vitro drought tolerance of Aronia melanocarpa ‘Nero’ by exposing micropropagated plantlets to nutrient media containing different concentrations of PEG-8000 (0%, 1%, and 2%) during the rooting stage. Results showed that increasing PEG concentrations led to a reduction in survival, rooting, plantlet growth, and physiological parameters. The 0% PEG treatment resulted in the highest survival rate (95.83%), root number, and chlorophyll content, while the 2% PEG treatment significantly hindered these parameters. These findings indicate that Aronia melanocarpa 'Nero' is sensitive to drought stress, with reduced growth and physiological activity under higher PEG concentrations.

Genome-wide identification of the endonuclease family genes implicates potential roles of TaENDO23 in drought-stressed response and grain development in wheat

BackgroundEndonucleases play a crucial role in plant growth and stress response by breaking down nuclear DNA. However, the specific members and biological functions of the endonuclease encoding genes in wheat remain to be determined.ResultsIn this study, we identified a total of 26 TaENDO family genes at the wheat genome-wide level. These genes were located on chromosomes 2 A, 2B, 2D, 3 A, 3B, and 3D and classified into four groups, each sharing similar gene structures and conserved motifs. Furthermore, we identified diverse stress-response and growth-related cis-elements in the promoter of TaENDO genes, which were broadly expressed in different organs, and several TaENDO genes were significantly induced under drought and salt stresses. We further examined the biological function of TaENDO23 gene since it was rapidly induced under drought stress and exhibited high expression in spikes and grains. Subcellular localization analysis revealed that TaENDO23 was localized in the cytoplasm of wheat protoplasts. qRT-PCR results indicated that the expression of TaENDO23 increased under PEG6000 and abscisic acid treatments, but decreased under NaCl treatment. TaENDO23 mainly expressed in leaves and spikes. A kompetitive allele-specific PCR (KASP) marker was developed to identify single nucleotide polymorphisms in TaENDO23 gene in 256 wheat accessions. The alleles with TaENDO23-HapI haplotypes had higher grain weight and size compared to TaENDO23-HapII. The geographical and annual frequency distributions of the two TaENDO23 haplotypes revealed that the elite haplotype TaENDO23-HapI was positively selected in the wheat breeding process.ConclusionWe systematically analyzed the evolutionary relationships, gene structure characteristics, and expression patterns of TaENDO genes in wheat. The expression of TaENDO23, in particular, was induced under drought stress, mainly expressed in the leaves and grains. The KASP marker of TaENDO23 gene successfully distinguished between the wheat accessions, revealing TaENDO23-HapI as the elite haplotype associated with improved grain weight and size. These findings provide insights into the evolution and characteristics of TaENDO genes at the genome-wide level in wheat, laying the foundation for further biological analysis of TaENDO23 gene, especially in response to drought stress and grain development.

Molecular Characterization of Peroxidase (PRX) Gene Family in Cucumber.

Background: The Peroxidase (PRX) gene family is essential for plant growth and significantly contributes to defense against stresses. However, information about PRX genes in cucumber (Cucumis sativus L.) remains limited. Methods: In this present study, CsPRX genes were identified and characterized using bioinformatics analysis. The expression pattern analysis of CsPRX genes were examined utilizing the RNA-seq data of cucumber from public databases and real-time quantitative PCR (qRT-PCR) analysis. Results: Here, we identified 60 CsPRX genes and mapped them onto seven chromosomes of cucumber. The CsPRX proteins exhibited the presence of 10 conserved motifs, with motif 8, motif 2, motif 5, and motif 3 consistently appearing across all 60 CsPRX protein sequences, indicating the conservation of CsPRX proteins. Furthermore, RNA-seq analysis revealed that differential expression of CsPRX genes in various tissues. Notably, a majority of the CsPRX genes exhibited significantly higher expression levels in the root compared to the other plant tissues, suggesting a potential specialization of these genes in root function. In addition, qRT-PCR analysis for four selected CsPRX genes under different stress conditions indicated that these selected CsPRX genes demonstrated diverse expression levels when subjected to NaCl, CdCl2, and PEG treatments, and the CsPRX17 gene was significantly induced by NaCl, CdCl2, and PEG stresses, suggesting a vital role of the CsPRX17 gene in response to environmental stresses. Conclusions: These findings will contribute valuable insights for future research into the functions and regulatory mechanisms associated with CsPRX genes in cucumber.

PEG treatment is unsuitable to study root related traits as it alters root anatomy in barley (Hordeum vulgare L.)

BackgroundThe frequency and severity of abiotic stress events, especially drought, are increasing due to climate change. The plant root is the most important organ for water uptake and the first to be affected by water limitation. It is therefore becoming increasingly important to include root traits in studies on drought stress tolerance. However, phenotyping under field conditions remains a challenging task. In this study, plants were grown in a hydroponic system with polyethylene glycol as an osmotic stressor and in sand pots to examine the root system of eleven spring barley genotypes. The root anatomy of two genotypes with different response to drought was investigated microscopically.ResultsRoot diameter increased significantly (p < 0.05) under polyethylene glycol treatment by 54% but decreased significantly (p < 0.05) by 12% under drought stress in sand pots. Polyethylene glycol treatment increased root tip diameter (51%) and reduced diameter of the elongation zone (14%) compared to the control. Under drought stress, shoot mass of plants grown in sand pots showed a higher correlation (r = 0.30) with the shoot mass under field condition than polyethylene glycol treated plants (r = -0.22).ConclusionThese results indicate that barley roots take up polyethylene glycol by the root tip and polyethylene glycol prevents further water uptake. Polyethylene glycol-triggered osmotic stress is therefore unsuitable for investigating root morphology traits in barley. Root architecture of roots grown in sand pots is more comparable to roots grown under field conditions.

Superior osmotic stress tolerance in oilseed rape transformed with wild-type Rhizobium rhizogenes

Key messageNatural transformation with R. rhizogenes enhances osmotic stress tolerance in oilseed rape through increasing osmoregulation capacity, enhancing maintenance of hydraulic integrity and total antioxidant capacity.Transformation of plants using wild strains of agrobacteria is termed natural transformation and is not covered by GMO legislation in, e.g., European Union and Japan. In this study, offspring lines of Rhizobium rhizogenes naturally transformed oilseed rape (Brassica napus), i.e., A11 and B3 (termed root-inducing (Ri) lines), were investigated for osmotic stress resilience. Under polyethylene glycol 6000 (PEG) 10% (w/v)-induced osmotic stress, the Ri lines, particularly A11, had less severe leaf wilting, higher stomatal conductance (8.2 times more than WT), and a stable leaf transpiration rate (about 2.9 mmol m−2 s−1). Although the leaf relative water content and leaf water potential responded similarly to PEG treatment between the Ri lines and WT, a significant reduction of the turgid weight to dry weight ratio in A11 and B3 indicated a greater capacity of osmoregulation in the Ri lines. Moreover, the upregulation of plasma membrane intrinsic proteins genes (PIPs) in roots and downregulation of these genes in leaves of the Ri lines implied a better maintenance of hydraulic integrity in relation to the WT. Furthermore, the Ri lines had greater total antioxidant capacity (TAC) than the WT under PEG stress. Collectively, the enhanced tolerance of the Ri lines to PEG-induced osmotic stress could be attributed to the greater osmoregulation capacity, better maintenance of hydraulic integrity, and greater TAC than the WT. In addition, Ri-genes (particularly rolA and rolD) play roles in response to osmotic stress in Ri oilseed rape. This study reveals the potential of R. rhizogenes transformation for application in plant drought resilience.