Search Results (114)

As climate change intensifies soil drought and salinization, enhancing the drought and salt tolerance of moso bamboo (Phyllostachys edulis) is urgent. DHN genes are crucial for plant stress responses and have gained attention in plant resistance to drought and salinity. This study identified nine DHN family members (PeDHN1–PeDHN9) from moso bamboo, which were classified into K₂S-type, YK₂S-type, and Y₂K₂S-type dehydrins based on their characteristic motifs. We employed integrated bioinformatics approaches to analyze their gene structure, phylogeny, biological properties, and expression patterns under various stress conditions. Five genes (PeDHN2/4/5/6/8), which may have significant functional roles in moso bamboo, were selected for cloning. Subcellular localization experiments showed that YK₂S-type dehydrins (PeDHN2/5/6) localized to both the nucleus and the plasma membrane, while K₂S-type dehydrins (PeDHN4/8) were exclusively localized to the plasma membrane, indicating functional differentiation. qRT-PCR analysis revealed that the expression of PeDHN2/4/5/6/8 was significantly responsive to stress treatments with ABA, NaCl, and PEG. Additionally, overexpressing these genes in rice significantly enhanced seed germination rates and root development under salt and ABA stress, further confirming that PeDHN2/4/5/6/8 contribute to enhancing plant stress tolerance. Yeast one-hybrid assays demonstrated that two PeABF1 proteins could bind to the promoter of PeDHN4, suggesting that PeDHN4 may regulate stress responses through the ABA signaling pathway. Thus, these findings demonstrate that PeDHN2/4/5/6/8 are closely related to the response of moso bamboo to drought and saline-alkali environments. This research offers insights for moso bamboo cultivation and theoretical foundations for bamboo genetic improvement in stress environments. Full article

Dehydrins (DHNs; late embryogenesis-abundant D11 family) are a class of hydrophilic proteins involved in plant abiotic stress response. However, there is less information regarding DHN gene function in cucurbit crops. Herein, 34 DHN gene family members were identified and characterized in Cucumis sativus, Cucumis melo, Citrullus lanatus, Benincasa hispida, Lagenaria siceraria, and Cucurbita maxima. The DHN genes in the six cucurbit crops exhibited greater collinearity within subfamilies than between different subfamilies. Responses to stress (including low-temperature, salt, cadmium, and aluminum stress) varied among the DHN members, with a significant alteration in the expression of the acidic SnKn-type DHN gene CmDHN3 in response to aluminum stress. Subcellular localization analysis confirmed that CmDHN3 is expressed in the nucleus and cytoplasm. Virus-induced gene silencing (VIGS) revealed a remarkable decrease in CmDHN3 expression, which markedly increased malondialdehyde content, relative conductivity, and proline content in the roots and leaves of plants under aluminum stress. Transcriptome analysis showed that the decreased CmDHN3 expression reduced the expression of water channel protein-encoding genes. Interactions between CmDHN3 and CmAQP1 (MELO3C007188) and between CmDHN3 and CmAQP2 (MELO3C020774) were confirmed using yeast two-hybrid assays. These results clarify the pathway by which dehydrin genes are involved in the transcriptional-level response of melon to aluminum stress and provide a theoretical basis to comprehensively analyze the functions of this gene family in cucurbit crops. Full article

Dehydrins are stress-inducible proteins with protective functions, characterized by high hydrophilicity, thermostability, and a low degree of secondary structure. They stabilize cellular membranes, preserve macromolecule conformation, and support enzymatic and structural protein functions. Their accumulation in plant tissues under drought is regulated by abscisic acid (ABA)-dependent and ABA-independent pathways. Ethylene plays a key role in stress adaptation, but its relationship with dehydrin accumulation remains unclear. This study investigates how ethylene influences dehydrin expression in Arabidopsis thaliana during prolonged dehydration using transcript profiling and immunodetection in wild-type (Col-0), ethylene-constitutive (ctr1-1), and ethylene-insensitive (ein3eil1) mutants. Comparative analyses showed increased survival of ctr1-1 plants under dehydration stress, likely due to reduced oxidative damage. Analysis of dehydrin-coding genes identified multiple Ethylene Response Factor (ERF) binding sites, flanking the transcription start sites, which suggests a fine-tuned ethylene-dependent regulation. The ability of ethylene signaling to either suppress or stabilize particular dehydrins was demonstrated by RT-qPCR and immunodetection experiments. Under drought stress, ethylene signaling appeared to suppress root-specific dehydrins. A Y-segment-containing protein with approximate molecular weight of 20 kDa showed decreased levels in ctr1-1 and higher accumulation in ein3eil1, indicating that ethylene signaling acts as a negative regulator. These results provide new information on the dual role of ethylene in dehydrin control, highlighting its function as a molecular switch in stress adaptive responses. Full article

Dehydrins (DHNs) belong to the second family of late embryogenesis abundant (LEA) proteins, which are widely distributed in plants. We cloned a SK₃-type DHN gene named WZY1-2 in Zheng yin 1 cultivar of Triticum aestivum. An ERF-type transcription factor TaERF4a was found to be involved in the regulation of the dehydrin WZY1-2 gene in our last report. The stress-responsive ability and dual-luciferase assay demonstrated that TaERF4a positively regulates WZY1-2 gene transcription under stress conditions. In this study, we further characterized the role of the transcription factor TaERF4a in plant drought tolerance. Arabidopsis thaliana heterologously overexpressing TaERF4a exhibited higher survival rate, increased superoxide dismutase (SOD) activity, elevated proline and chlorophyll content, and reduced malondialdehyde (MDA) content under drought conditions. Conversely, silencing TaERF4a in Chinese spring wheat using the virus-induced gene silencing (VIGS) method increased the sensitivity of plants to drought stress. Furthermore, we identified the specific binding site of TaERF4a in the WZY1-2 promoter. Electrophoretic mobility shift assay (EMSA) and dual-luciferase reporter assay demonstrated that TaERF4a activates the expression of the WZY1-2 dehydrin gene through binding to the DRE cis-element in its promoter. Taken together, the results of our study indicate that TaERF4a positively regulates the expression of the dehydrin WZY1-2 gene and enhances drought tolerance in plants. Full article

Salt stress is a major abiotic stress that interferes with plant growth and affects crop production. Dehydrin (DHN), a member of the late embryogenesis abundant (LEA) protein family, was considered to be a stress protein involved in the protective reaction of plant dehydration. Our previous research has shown that overexpression of the Suaeda salsa SsDHN gene enhances tolerance to salt stress in tobacco. However, the research on its protection in photosynthesis under salt stress remains unclear. In this study, gene overexpression (SsDHN-OE) tobacco plants were utilized to study the effect of the SsDHN gene on plant photosynthesis under salt stress. Our findings showed that overexpression of SsDHN increased the biomass, leaf area, root length, and root surface area in tobacco seedlings under salt stress conditions. The transgenic tobacco with overexpression of SsDHN had obvious stomatal closure, which effectively alleviated the adverse effects of salt stress on photosynthetic efficiency. Overexpression of the SsDHN gene in tobacco can effectively reduce the degree of photoinhibition and chloroplast damage caused by salt stress. Moreover, the SsDHN-overexpressing transgenic tobacco plants exhibited a decrease in oxidative damage and protected membrane structures related to photosynthesis by increasing antioxidant enzyme activity and antioxidant substance content. It was further found that the expression levels of photosynthetic and antioxidant-related genes Rubisco, SBPase, POD7, CAT3, APX2, and SOD3 were significantly up-regulated by overexpressing the SsDHN gene in tobacco seedlings under salt stress. In conclusion, the SsDHN gene might improve the salt stress resistance of tobacco seedlings and be involved in regulating photosynthesis and antioxidant activity under salt stress. Full article

Intrinsically disordered proteins (IDPs) include two types of proteins: partial disordered regions (IDRs) and wholly disordered proteins (WDPs). Extensive studies focused on the proteins with IDRs, but less is known about WDPs because of their difficult-to-form folded tertiary structure. In this study, we developed a bioinformatics method for screening more than 50 amino acids in the genome level and found a total of 27 categories, including 56 WDPs, in Arabidopsis. After comparing with 56 randomly selected structural proteins, we found that WDPs possessed a more wide range of theoretical isoelectric point (PI), a more negative of Grand Average of Hydropathicity (GRAVY), a higher value of Instability Index (II), and lower values of Aliphatic Index (AI). In addition, by calculating the FCR (fraction of charged residue) and NCPR (net charge per residue) values of each WDP, we found 20 WDPs in R1 (FCR < 0.25 and NCPR < 0.25) group, 15 in R2 (0.25 ≤ FCR ≤ 0.35 and NCPR ≤ 0.35), 19 in R3 (FCR > 0.35 and NCPR ≤ 0.35), and two in R4 (FCR > 0.35 and NCPR > 0.35). Moreover, the gene expression and protein-protein interaction (PPI) network analysis showed that WDPs perform different biological functions. We also showed that two WDPs, SIS (Salt Induced Serine rich) and RAB18 (a dehydrin family protein), undergo the in vitro liquid-liquid phase separation (LLPS). Therefore, our results provide insight into understanding the biochemical characters and biological functions of WDPs in plants. Full article

Dehydrins (Dhns) are a group of intrinsically disordered land plant proteins that are closely associated with tolerance of dehydrative stress. Dhns are recognized and classified by the presence and sequence of five different conserved segments, varying in length from 8 to 15 residues, separated by highly variable disordered regions. In addition to one or more copies of the diagnostic, fifteen-residue K segment, most Dhns can be classified into one of three major groups based on the mutually exclusive presence of three other conserved segments (H, Y, or F), with all three groups typically incorporating multi-serine S segments. Many Dhns also include repeat structures. From an input library of 8675 non-redundant candidate sequences, a specialized R script identified and classified 2658 complete and 236 partial Dhn sequences in all major green plant (Viridiplantae) lineages, including a few green algal genera. An examination of the connecting segments bridging the conserved segments identified additional conserved patterns, suggesting that multi-Y, S-K, and K-S domains may act as functional units. Dhn Decoder identified 857 Dhns with repeat structures, ranging from 3 short, simple repeats to elaborate variations with up to 45 repeats or repeats of up to 85 residues comprising 1 or more of the conserved segments, suggesting that internal sequence duplication is an important mode of evolution in Dhns. Full article

Saffron (Crocus sativus L.), a perennial geophyte from the Iridaceae family, blooms in autumn and thrives in Mediterranean-like climates. It is highly valued for its therapeutic and commercial uses. While saffron cultivation generally requires minimal water, insufficient irrigation can negatively impact its yield. Although numerous studies have explored the detrimental impact of drought on saffron under field conditions, its impact in vitro remains largely unexplored. The present study aims to investigate the effects of polyethylene glycol (PEG) 6000 at concentrations of 0%, 5%, and 10% in inducing drought stress on saffron shoots under controlled conditions. The research focuses on evaluating morphological, physiological, and biochemical changes and analyzing the expression of drought-responsive genes. Shoot establishment was carried out on Murashige and Skoog (MS) medium supplemented with 6 mg/L 6-benzyladenine (BAP) and 1 mg/L naphthaleneacetic acid (NAA), while PEG 6000 was used to induce drought stress. Various morphological, biochemical, and molecular parameters were assessed 30 days after stress induction. Increasing PEG concentrations in the medium significantly reduced shoot regeneration, leading to increased apical tissue browning. Significant chlorophyll and carotenoid level changes were observed in shoots exposed to higher PEG concentrations. PEG-induced drought led to decreased plant growth and biomass and lowered relative water content of leaves. Lipid peroxidation, membrane damage, and H₂O₂ content increased, indicating heightened stress levels. Proline concentration significantly increased in plants subjected to 5% and 10% PEG compared to controls. Non-enzymatic antioxidant activity (phenolics, flavonoids, % inhibition, total reducing power, and total antioxidant activity) also increased with the severity of stress. In contrast, a decrease in the activity of superoxide dismutase (SOD) and peroxidase was observed in PEG-treated shoots. Significant changes in the expression of drought-related genes, such as DREB1, DREB2, AREB1, DHN1 (Dehydrin), and SnRK2, were observed in shoots exposed to 5% and 10% PEG. In conclusion, the study highlights that PEG, as an inducer of drought stress, negatively impacts saffron’s growth and physiological responses under in vitro conditions. It also triggers significant changes in biochemical and molecular mechanisms, indicating the plant’s susceptibility to water scarcity. Full article

Late embryogenesis abundant (LEA) proteins are a class of proteins associated with osmotic regulation and plant tolerance to abiotic stress. However, studies on the LEA gene family in the alpine cold-tolerant herb are still limited, and the phylogenetic evolution and biological functions of its family members remain unclear. In this study, we conducted genome-wide identification, phylogenetic evolution, and abiotic stress response analyses of LEA family genes in Notopterygium species, alpine cold-tolerant medicinal herbs in the Qinghai–Tibet Plateau and adjacent regions. The gene family identification analysis showed that 23, 20, and 20 LEA genes were identified in three Notopterygium species, N. franchetii, N. incisum, and N. forrestii, respectively. All of these genes can be classified into six LEA subfamilies: LEA_1, LEA_2, LEA_5, LEA_6, DHN (Dehydrin), and SMP (seed maturation protein). The LEA proteins in the three Notopterygium species exhibited significant variations in the number of amino acids, physical and chemical properties, subcellular localization, and secondary structure characteristics, primarily demonstrating high hydrophilicity, different stability, and specific subcellular distribution patterns. Meanwhile, we found that the members of the same LEA subfamily shared similar exon–intron structures and conserved motifs. Interestingly, the chromosome distributions of LEA genes in Notopterygium species were scattered. The results of the collinearity analysis indicate that the expansion of the LEA gene family is primarily driven by gene duplication. A Ka/Ks analysis showed that paralogous gene pairs were under negative selection in Notopterygium species. A promoter cis-acting element analysis showed that most LEA genes possessed multiple cis-elements connected to plant growth and development, stress response, and plant hormone signal transduction. An expression pattern analysis demonstrated the species-specific and tissue-specific expression of NinLEAs. Experiments on abiotic stress responses indicated that the NinLEAs play a crucial role in the response to high-temperature and drought stresses in N. franchetii leaves and roots. These results provide novel insights for further understanding the functions of the LEA gene family in the alpine cold-tolerant Notopterygium species and also offer a scientific basis for in-depth research on the abiotic stress response mechanisms and stress-resistant breeding. Full article

A previous exposure to drought priming (DP) or salt priming (SP) could significantly improve future tolerance to both the same and different abiotic stresses, which is an effective mitigation strategy for plants to adapt to changing environmental conditions. If the type of stress priming is different from subsequent abiotic stress, this indicates that plants are trained to acquire cross tolerance. The objective of this study was to explore DP-regulated cross tolerance to salt stress and SP-induced cross tolerance to drought associated with changes in growth, antioxidant defense, proline metabolism, and the expression of the dehydration-responsive gene Dehydrin b involved in the stabilization of membrane systems, cryoprotection of intracellular proteins, and enhancement in water retention capacity in white clover (Trifolium repens). Plants were pretreated by initial DP or SP and then subjected to subsequent salt stress or drought stress for 10 days, respectively. The results demonstrated that DP significantly increased number of roots during subsequent salt stress, whereas SP significantly improved stem length, root length, and number of roots under drought stress, which indicated that the SP exhibited more pronounced and positive effects on mitigating subsequent drought-induced growth retardant. Both salt stress and drought resulted in significant increases in electrolyte leakage and contents of superoxide anion, hydrogen peroxide, and malonaldehyde due to reduced superoxide dismutase, peroxide, and catalase, as well as key enzyme activities in the ascorbate–glutathione cycle. SP or DP could significantly enhance these enzyme activities to alleviate subsequent drought- or salt-induced oxidative damage. SP or DP also significantly improved the accumulation of proline contributing to better water homeostasis by promoting biosynthetic enzyme activities (Δ¹-pyrroline-5-carboxylate synthetase and aminotransferase) and restricting proline dehydrogenase activity for proline degradation under drought or salt stress, respectively. In addition, SP significantly up-regulated the expression of dehydrin b under drought stress, but DP failed to induce the expression of dehydrin b in response to subsequent salt stress. The current findings proved that the pre-exposure of white clover plants to DP or SP could effectively mitigate the negative effects of subsequent salt stress or drought related to some common and different pathways. Plants pretreated by initial DP or SP exhibited better adaption to subsequent different stress by regulating growth, physiological, metabolic, and transcriptional changes. Full article

Drought adversely affects plant growth, which leads to reduced crop yields and exacerbates food insecurity. Late embryogenesis abundant (LEA) proteins are crucial for plants’ responses to abiotic stresses. This research further investigates the role of SiLEA5 by utilizing transgenic tomatoes under drought stress. The expression of SiLEA5 was upregulated under drought and abscisic acid (ABA) treatment, resulting in decreased electrolyte leakage and malondialdehyde content, alongside increased levels of osmotic regulators and antioxidant enzyme activity. These biochemical alterations reduce oxidative damage and enhance drought resistance. qRT-PCR analysis revealed the upregulation of ABA signaling genes and key enzymes involved in proline biosynthesis (P5CS) and dehydrin (DHN) synthesis under drought stress. Additionally, overexpression of SiLEA5 increased the net photosynthetic rate (Pn) and fruit yield of tomatoes by regulating stomatal density and aperture. These findings suggest that SiLEA5 may be a potential target for improving drought tolerance in tomatoes and other crops. Full article

Drought, a significant environmental challenge, presents a substantial risk to worldwide agriculture and the security of food supplies. In response, plants can perceive stimuli from their environment and activate defense pathways via various modulating networks to cope with stress. Drought tolerance, a multifaceted attribute, can be dissected into distinct contributing mechanisms and factors. Osmotic stress, dehydration stress, dysfunction of plasma and endosome membranes, loss of cellular turgidity, inhibition of metabolite synthesis, cellular energy depletion, impaired chloroplast function, and oxidative stress are among the most critical consequences of drought on plant cells. Understanding the intricate interplay of these physiological and molecular responses provides insights into the adaptive strategies plants employ to navigate through drought stress. Plant cells express various mechanisms to withstand and reverse the cellular effects of drought stress. These mechanisms include osmotic adjustment to preserve cellular turgor, synthesis of protective proteins like dehydrins, and triggering antioxidant systems to counterbalance oxidative stress. A better understanding of drought tolerance is crucial for devising specific methods to improve crop resilience and promote sustainable agricultural practices in environments with limited water resources. This review explores the physiological and molecular responses employed by plants to address the challenges of drought stress. Full article

The olive tree is well adapted to the Mediterranean climate, but how orchards based on intensive practices will respond to increasing drought is unknown. This study aimed to determine if the application of a commercial biostimulant improves olive tolerance to drought. Potted plants (cultivars Arbequina and Galega) were pre-treated with an extract of Ascophyllum nodosum (four applications, 200 mL of 0.50 g/L extract per plant), and were then well irrigated (100% field capacity) or exposed to water deficit (50% field capacity) for 69 days. Plant height, photosynthesis, water status, pigments, lipophilic compounds, and the expression of stress protective genes (OeDHN1—protective proteins’ dehydrin; OePIP1.1—aquaporin; and OeHSP18.3—heat shock proteins) were analyzed. Water deficit negatively affected olive physiology, but the biostimulant mitigated these damages through the modulation of molecular and physiological processes according to the cultivar and irrigation. A. nodosum benefits were more expressive under water deficit, particularly in Galega, promoting height (increase of 15%) and photosynthesis (increase of 34%), modulating the stomatal aperture through the regulation of OePIP1.1 expression, and keeping OeDHN1 and OeHSP18.3 upregulated to strengthen stress protection. In both cultivars, biostimulant promoted carbohydrate accumulation and intrinsic water-use efficiency (iWUE). Under good irrigation, biostimulant increased energy availability and iWUE in Galega. These data highlight the potential of this biostimulant to improve olive performance, providing higher tolerance to overcome climate change scenarios. The use of this biostimulant can improve the establishment of younger olive trees in the field, strengthen the plant’s capacity to withstand field stresses, and lead to higher growth and crop productivity. Full article

Understanding the responses of olive trees to drought stress is crucial for improving cultivation and developing drought-tolerant varieties. Water transport and storage within the plant is a key factor in drought-tolerance strategies. Water management can be based on a variety of factors such as stomatal control, osmoprotectant molecules, proteins and wood properties. The aim of the study was to evaluate the water management strategy under drought stress from an anatomical and biochemical point of view in three young Italian olive cultivars (Giarraffa, Leccino and Maurino) previously distinguished for their physiological and metabolomic responses. For each cultivar, 15 individuals in pots were exposed or not to 28 days of water withholding. Every 7 days, the content of sugars (including mannitol), proline, aquaporins, osmotins, and dehydrins, in leaves and stems, as well as the chemical and anatomical characteristics of the wood of the three cultivars, were analyzed. ‘Giarraffa’ reduced glucose levels and increased mannitol production, while ‘Leccino’ accumulated more proline. Both ‘Leccino’ and ‘Maurino’ increased sucrose and aquaporin levels, possibly due to their ability to remove embolisms. ‘Maurino’ and ‘Leccino’ accumulated more dehydrins and osmotins. While neither genotype nor stress affected wood chemistry, ‘Maurino’ had a higher vessel-to-xylem area ratio and a larger hydraulic diameter, which allows it to maintain a high transpiration rate but may make it more susceptible to cavitation. The results emphasized the need for an integrated approach, highlighting the importance of the relative timing and sequence of each parameter analyzed, allowing, overall, to define a “strategy” rather than a “response” to drought of each cultivar. Full article

Under a water deficit, the protective proteins known as dehydrins (DHNs) prevent nonspecific interactions in protein and membrane structures and their damage, in addition to playing an antioxidant role. The DHNs of a widespread xerophytic species Scots pine (Pinus sylvestris L.) have been poorly studied, and their role in resistance to water deficits has not been revealed. In this paper, we have expanded the list of DHNs that accumulate in the cells of Scots pine under the conditions of water deficits and revealed their relationship with the effects of water deficits. In this investigation, callus cultures of branches and buds of Scots pine were used. A weak water deficit was created by adding polyethylene glycol to the culture medium. Under the conditions of a water deficit, the activity of catalase and peroxidase enzymes increased in the callus cultures. A moderate decrease in the total water content was correlated with a decrease in the growth rate of the callus cultures, as well as with an increase in the activity of lipid peroxidation. The accumulation of Mr 72, 38, and 27 kDa DHNs occurred in the callus cultures of buds, and the accumulation of Mr 72 and 27 kDa DHNs positively correlated with the lipid peroxidation activity. An increase in the content of DHNs was observed in cultures that differed in origin, growth indicators, and biochemical parameters, indicating the universality of this reaction. Thus, previously undescribed DHNs were identified, the accumulation of which is caused by water deficiency and is associated with manifestations of oxidative stress in the kidney cells of Scots pine. Full article