24-epibrassinolide Research Articles

Investigating the influence of selenium and epibrassinolide on antioxidant activity, proline accumulation, and protein expression profiles in wheat plants experiencing heat and drought stress

In the current investigation, the combination of selenium (Se) and epibrassinolide (EBL) exhibited a promising alleviative response against the concurrent stress of heat and drought in wheat plants. The compromised growth and photosynthetic performance of wheat plants under the combined stress of heat and drought were substantially improved with the treatment involving Se and EBL. This improvement was facilitated through the expression of Q9FIE3 and O04939 proteins, along with enhanced antioxidant activities. The heightened levels of antioxidant enzymes and the accumulation of osmoprotectant proline helped mitigate the overaccumulation of reactive oxygen species (ROS), including electrolyte leakage, H2O2 accumulation, and lipid peroxidation, thus conferring tolerance against the combined stress of heat and drought. Studies have demonstrated that Se and EBL can assist wheat plants in recuperating from the adverse effects of heat and drought. As such, they are essential components of sustainable farming methods that aim to increase crop productivity.

Brassinolide and gibberellin promote grape fruit development and quality

Brassinosteroid (BR) and Gibberellins (GA) are important hormones that significantly influences grapeberry development and ripening. In the present study, grape clusters were soaked separately with EBR (Epi brassinolide), GA3, and EBR+GA3 during fruit development. Results showed that anthocyanin content, soluble solids, and titratable acid content were all enhanced by EBR treatment, however fruit weight, transverse and longitudinal longitude, and hardness were not significantly changed, furthermore, GA3 treatment increased the fruit weight, longitudinal and transverse longitude, and hardness, decreased titratable acid, and increased the solid acid ratio; The EBR+GA3 significantly improved grape fruit quality, increased fruit anthocyanin content, reduced titratable acid content, improved sugar-acid ratio, and significantly improved fruit weight, transverse and longitudinal longitude, and hardness. EBR and GA3 treatment increased the contents of alcohols, esters, ketones, terpenes, and phenols in aroma substances, and glucose and fructose. They also increased the sugar, aroma, and anthocyanin metabolism-related genes, while down-regulated the expression of acid-related genes. EBR also increased the GA metabolism associated genes, but GA3 decereaed BR metabolism assocated genes. BR and GA had a crosstalk of that VvGAI could interact with VvBZR1, VvGAI could inhibit the VvBZR1 binding to the VvGA20ox2 promoter that decreased the VvGA20ox2 gene expression, but EBR and GA3 could alleviate the inhibition. In conclusion, both BR and GA alone could improve fruit quality to some extent, and the combination of them can better integrate the advantages of single-use to improve the fruit quality and enhance the commerciality of the grape fruit.

BR regulates wheat root salt tolerance by maintaining ROS homeostasis.

Trace amounts of epibrassinolide (EpiBL) could partially rescue wheat root length inhibition in salt-stressed situation by scavenging ROS, and ectopic expression of TaDWF4 or TaBAK1 enhances root salt tolerance in Arabidopsis by balancing ROS level. Salt stress often leads to ion toxicity and oxidative stress, causing cell structure damage and root development inhibition in plants. While prior research indicated the involvement of exogenous brassinosteroid (BR) in plant responses to salt stress, the precise cytological role and the function of BR in wheat root development under salt stress remain elusive. Our study demonstrates that 100mM NaCl solution inhibits wheat root development, but 5nM EpiBL partially rescues root length inhibition by decreasing H2O2 content, oxygen free radical (OFR) content, along with increasing the peroxidase (POD) and catalase (CAT) activities in salt-stressed roots. The qRT-PCR experiment also shows that expression of the ROS-scavenging genes (GPX2 and CAT2) increased in roots after applying BR, especially during salt stress situation. Transcriptional analysis reveals decreased expression of BR synthesis and root meristem development genes under salt stress in wheat roots. Differential expression gene (DEG) enrichment analysis highlights the significant impact of salt stress on various biological processes, particularly "hydrogen peroxide catabolic process" and "response to oxidative stress". Additionally, the BR biosynthesis pathway is enriched under salt stress conditions. Therefore, we investigated the involvement of wheat BR synthesis gene TaDWF4 and BR signaling gene TaBAK1 in salt stress responses in roots. Our results demonstrate that ectopic expression of TaDWF4 or TaBAK1 enhances salt tolerance in Arabidopsis by balancing ROS (Reactive oxygen species) levels in roots.

Comparative and interactive response of salicylic acid, 24–epibrassinolide or sodium nitroprusside against cadmium stress in Linum usitatissimum

AbstractConcerns regarding the effects of heavy metals (HMs) on agricultural productivity have grown over time. Because HM stress disrupts a number of the plants' physiological-biochemical and metabolic processes, it severely limits production. Phytohormones can effectively improve plants resistance to HM stress. This work was done to examine the comparative effectiveness of salicylic acid (SA), 24–epibrassinolide (EBL) and sodium nitroprusside (SNP) on photosynthetic attributes, growth, & antioxidant enzymes activity in Linum usitatissimum cv. RLC–6 (flax) subjected to cadmium (Cd) stress during vegetative growth stages. Cd considerably decreases the length, biomass, leaf diameter, chlorophyll content, and photosynthetic traits; and further triggered ROS and MDA content in plant. Moreover, exogenous application of SA, EBL and SNP individually and in combination improved the antioxidant enzymatic machinery by increasing the levels of superoxide dismutase (SOD), peroxidase (POX), and catalase (CAT) and decrease the superoxide, hydrogen peroxide, scavenges ROS and MDA accumulation. Furthermore, submission of phytohormones also caused proline to accumulate and the activities of carbonic anhydrase (CA) and nitrate reductase (NR) to be activated which were impaired due to Cd stress. Among the phytohormones, the most effective method for dropping the damaging impacts of Cd and promoting plant growth and development was EBL. However, combined application of all three phytohormones (SA + EBL + SNP) proved to be the best. Thus, it can be concluded that, these augmented activity of antioxidants and proline elicited by application of phytohormones, would have continued to be able to give Linum usitatissimum exposed to Cd stress resistance.

Epibrassinolide application improves Brassica juncea L. performance by augmenting gas exchange markers, stomatal behavior, cellular viability, enzymatic activities and yield attributes

Epibrassinolide (EBL) is an emerging plant growth regulator of the brassinosteroids group that has the potential to modulate various morpho-physiological processes in plants. Therefore, due to its key role in boosting plant functioning mechanisms, it is widely used in agriculture to enhance crop growth and yield. The present research work was planned to investigate the role of exogenously applied EBL on the mustard crop by assessing morphological, physiochemical, and yield features. This randomized pot experiment contains three mustard cultivars i.e., Rohini (Roh), Chutki (Chk), and Nath Sona (Nas) and various graded levels of EBL, 0 (Control), 10−8 M, 10−7 M, 10−6 M, 10−5 M, and 10−4 M. EBL was applied twice by giving first spray at 50 days after sowing (DAS) and the second at 70 DAS. Evaluation of plants was done at 90 DAS to study phenological traits, gas exchange attributes, non-enzymatic antioxidant activities, and microscopical parameters. The yield and quality features were studied at 120 DAS. The results revealed that treatment of 10−6 M EBL proved effective and increased fresh weight by 17.76 %, 19.11 %, and 19.34 %, chlorophyll content by 26.50 %, 26.59 %, and 25.86 %, net photosynthetic rate by 45.67 %, 57.88 % and 49.76 %, protein content by 66.98 %, 68.62 % and 69.47 %, proline content by 25.70 %, 24.05 % and 21.87 %, ascorbate content by 94.91 %, 89.99 % and 87.43 %, carbonic anhydrase activity by 32.43 %, 30.84 % and 29.93 %, seed yield by 44.85 %, 51.36 %, and 57 % and oil yield by 68.75 %, 72.71 % and 74.34 % in cultivars Nas, Roh, and Chk respectively over the control plants. Moreover, 10−6 M EBL supplementation significantly improved stomatal aperture width and root cell longevity. Cultivar Nas, followed by cultivars Roh and Chk, showed better responses on nearly all characters studied. The effect of EBL treatment in terms of enhancing the performance of the crop being in the order of 10−6 M > 10−7 M > 10−8 M > 10−5 M > 10−4 M. It may be concluded that among sprayed EBL levels, two sprays of 10−6 M EBL proved efficacious in improving the phenotypic, physiochemical, and yield traits of mustard cultivars.

Brassinosteroids affect wood development and properties of Fraxinus mandshurica.

Xylem development plays a crucial role in wood formation in woody plants. In recent years, there has been growing attention towards the impact of brassinosteroids (BRs) on this xylem development. In the present study, we evaluated the dynamic variation of xylem development in Fraxinus mandshurica (female parent, M8) and a novel interspecific hybrid F. mandshurica × Fraxinus sogdiana (1601) from May to August 2020. We obtained RNA-Seq transcriptomes of three tissue types (xylem, phloem, and leaf) to identify the differences in xylem-differentially expressed genes (X-DEGs) and xylem-specifically expressed genes (X-SEGs) in M8 and 1601 variants. We then further evaluated these genes via weighted gene co-expression network analysis (WGCNA) alongside overexpressing FmCPD, a BR biosynthesis enzyme gene, in transient transgenic F. mandshurica. Our results indicated that the xylem development cycle of 1601 was extended by 2 weeks compared to that of M8. In addition, during the later wood development stages (secondary wall thickening) of 1601, an increased cellulose content (14%) and a reduced lignin content (11%) was observed. Furthermore, vessel length and width increased by 67% and 37%, respectively, in 1601 compared with those of M8. A total of 4589 X-DEGs were identified, including enzymes related to phenylpropane metabolism, galactose metabolism, BR synthesis, and signal transduction pathways. WGCNA identified hub X-SEGs involved in cellulose synthesis and BR signaling in the 1601 wood formation-related module (CESA8, COR1, C3H14, and C3H15); in contrast, genes involved in phenylpropane metabolism were significantly enriched in the M8 wood formation-related module (CCoAOMT and CCR). Moreover, overexpression of FmCPD in transient transgenic F. mandshurica affected the expression of genes associated with lignin and cellulose biosynthesis signal transduction. Finally, BR content was determined to be approximately 20% lower in the M8 xylem than in the 1601 xylem, and the exogenous application of BRs (24-epi brassinolide) significantly increased the number of xylem cell layers and altered the composition of the secondary cell walls in F. mandshurica. Our findings suggest that BR biosynthesis and signaling play a critical role in the differing wood development and properties observed between M8 and 1601 F. mandshurica.

Epi-Brassinolide Regulates ZmC4 NADP-ME Expression through the Transcription Factors ZmbHLH157 and ZmNF-YC2

Maize is a main food and feed crop with great production potential and high economic benefits. Improving its photosynthesis efficiency is crucial for increasing yield. Maize photosynthesis occurs mainly through the C4 pathway, and NADP-ME (NADP-malic enzyme) is a key enzyme in the photosynthetic carbon assimilation pathway of C4 plants. ZmC4-NADP-ME catalyzes the release of CO2 from oxaloacetate into the Calvin cycle in the maize bundle sheath. Brassinosteroid (BL) can improve photosynthesis; however, its molecular mechanism of action remains unclear. In this study, transcriptome sequencing of maize seedlings treated with epi-brassinolide (EBL) showed that differentially expressed genes (DEGs) were significantly enriched in photosynthetic antenna proteins, porphyrin and chlorophyll metabolism, and photosynthesis pathways. The DEGs of C4-NADP-ME and pyruvate phosphate dikinase in the C4 pathway were significantly enriched in EBL treatment. Co-expression analysis showed that the transcription level of ZmNF-YC2 and ZmbHLH157 transcription factors was increased under EBL treatment and moderately positively correlated with ZmC4-NADP-ME. Transient overexpression of protoplasts revealed that ZmNF-YC2 and ZmbHLH157 activate C4-NADP-ME promoters. Further experiments showed ZmNF-YC2 and ZmbHLH157 transcription factor binding sites on the -1616 bp and -1118 bp ZmC4 NADP-ME promoter. ZmNF-YC2 and ZmbHLH157 were screened as candidate transcription factors mediating brassinosteroid hormone regulation of the ZmC4 NADP-ME gene. The results provide a theoretical basis for improving maize yield using BR hormones.

Castasterone, a Plant Steroid Hormone, Affects Human Small-Cell Lung Cancer Cells and Reverses Multi-Drug Resistance.

Small-cell lung cancer (SCLC) has a dismal prognosis, in part because of the development of multi-drug resistance. Castasterone (CAS) is the metabolic precursor of the plant steroid hormone epibrassinolide (EB). In some plants, EB accounts for the total hormone activity, whereas in other plants, CAS is the active form. The effects of CAS, a BR present in most plants, on animal cells in general and cancer cells in particular have not been described. Here, we report the effects of CAS on drug-sensitive (H69) and drug-resistant (VPA17) SCLC cells. CAS was equally cytotoxic to both cell lines (IC50 = 1 μM), indicating a lack of cross-resistance. Pre-incubation of VPA17 cells with CAS for 96 h reversed drug resistance to etoposide and doxorubicin. Synergism between CAS and EB, as well as with chemotherapy drugs, was investigated by exposure of VPA17 cells to 1:1 ratios of CAS and the other drugs at the respective IC50 values, with dilutions at 0.25 to 2.0 × IC50 and determination of the combination index (CI). CAS and EB were additive, indicating that the two drugs act on the same pathway, whereas CAS-etoposide (CI = 0.77) and CAS-doxorubicin were synergistic, indicating that CAS and the two chemotherapeutic drugs act on different pathways. Apoptosis in SCLC cells was measured by immuno-detection of single-strand DNA breaks. Following 96 h incubation of SCLC H69 cells in CAS, the level of DNA breaks was similar to measurements made after incubation in EB and etoposide, indicating that CAS is pro-apoptotic. Incubation of SCLC cells in CAS led to a time-dependent reduction (by 80%) in the transcriptional activator β-catenin. These data indicate that CAS may act via Wnt signaling. Taken together, our study reveals that CAS is pharmacologically active in both drug-sensitive and drug-resistant SCLC cells.

Epibrassinolide Triggers Apoptotic Cell Death in SK-N-AS Neuroblastoma Cells by Targeting GSK3β in a ROS Generation-Dependent Way

Objective: Epibrassinolide (EBR), a biologically active member of the brassinosteroids plant hormone family, has been recently indicated as an apoptotic inducer in various cancer cells without affecting non-tumor cell proliferation. Glycogen synthase kinase 3β (GSK3β) was the first identified molecule that acts as a critical mediator of glycogen metabolism and insulin signaling mechanism. GSK3β has been described as an essential factor for tumor progression by phosphorylating and inactivating the pro-apoptotic family member of the Bcl-2 family, Bax. It was recently shown to regulate cell division, differentiation, and adhesion. Materials and Methods: To investigate the relative cell viability affected by EBR treatment and the preventive effect of N-acetyl cysteine (NAC) we performed MTT assay and FACS analysis, respectively. Colony formation and soft agar techniques were used to understand the inhibitory effect of EBR on colony formation and diameters. Annexin V-PI analysis by flow cytometry was performed for the measurement of the apoptotic cell percentages. Fluorescence microscopy was performed for the determination of mitochondria membrane potential following DiOC6 staining. The expression profiles of apoptotic proteins, as well as GSK3β and β-catenin were investigated by immunoblotting. Results: Our results indicated that EBR induced mitochodria-mediated apoptosis by inducing ROS generation which can be prevented by NAC, a reactive oxgen species scavenger. EBR-induced apoptosis can influence the inhibitory phosphorylation of GSK3β by Ser9 and prevents the translocation of the down-stream target, β-catenin. Conclusion: This study evaluated EBR as a potential apoptotic inducer in neuroblastoma cell line SK-N-AS and investigated the GSK3β involvement.

Brassinosteroid application increases tomato tolerance to salinity by changing the effects of stress on membrane integrity and gas exchange

Salinity is one of the environmental stresses that most cause losses in agricultural systems, including tomato production. Brassinosteroids, such as epibrassinolide (EBL), have multiple actions in essential processes in plants. Thus, the objective of this study was to evaluate the contributions of EBL to the growth, physiology, and production of tomato plants under salinity. The experiment was conducted in a factorial scheme, with five levels of water salinity (0.5 [the control], 1.5, 3.0, 4.5, and 6.0 dS m-1) and two concentrations of EBL (0 and 10-6 M). Salt stress reduced tomato growth, relative water content, membrane integrity, gas exchange, and fruit production. However, the exogenous application of EBL attenuated the adverse effects, partially improving these characteristics at all salinity levels. EBL reduced electrolyte leakage and increased membrane integrity and relative water content in control and stressed plants. Additionally, it increased the content of photosynthetic pigments, stomatal conductance, transpiration, and photosynthesis, which led to higher leaf dry mass production, fruit transverse diameter, and production per plant. Therefore, our results confirmed that foliar application of EBL improved the characteristics of stressed and non-stressed tomato plants.

Gemcitabine in combination with epibrassinolide enhanced the apoptotic response in an ER stress-dependent manner and reduced the epithelial-mesenchymal transition in pancreatic cancer cells.

Gemcitabine is a broad-spectrum antimetabolite and a deoxycytidine analog recognized as a standard therapy alone or in combination with other antineoplastic agents in the therapy of pancreas cancer. Drug resistance following gemcitabine treatment is a common phenomenon; therefore, combinational therapy models are usually preferred. Pancreatic ductal adenocarcinoma, or pancreas cancer, is the fourth leading cause of cancer-related deaths worldwide. With the increasing incidence of pancreatic cancer every year, the mortality rate is also rising significantly because of late diagnosis, and limited chemotherapy options. Adjuvant chemotherapy after surgical resection is the typical option for the treatment of early pancreatic cancer. Mostly, 5-fluorouracil/leucovorin with irinotecan and oxaliplatin (FOLFIRINOX) and gemcitabine/nab-paclitaxel is used for the prognosis of advanced pancreatic cancer; however, chemoresistance usually occurs limiting the effectiveness of the chemotherapy. Therefore, most of the studies are focused on gemcitabine combination with other drugs to overcome the situation. As an apoptotic agent and a member of brassinosteroids, epibrassinolide (EBR) induces endoplasmic reticulum (ER) stress-dependent cell death in different cancer cells, as shown by our group. In this study, we aimed to enhance the gemcitabine apoptotic effect by EBR combined treatment in pancreatic cancer cells. EBR treatment reduced cell viability and inhibited cell proliferation in PANC-1, MIA PaCa-2, and AsPC-1 cells. Each pancreatic cancer cell gave different responses to the EBR treatment because of different aggressiveness. However, EBR induced apoptosis through increasing ROS generation, which was associated with ER stress in PANC-1 and MIA PaCa-2 cells. Gemcitabine alone reduced the cell viability of each pancreatic cancer cell line; however, combination with EBR led to further induction of apoptotic cell death in each pancreatic cancer cell line. In addition, combined treatment of gemcitabine and EBR further decreased N-cadherin and vimentin expressions, suggesting that epithelial-mesenchymal transition of pancreatic cells is reduced. In conclusion, EBR had therapeutic potential to avoid the gemcitabine-induced side effects during the treatment of pancreatic cancer.

Epibrassinolide prevents tau hyperphosphorylation via GSK3β inhibition in vitro and improves Caenorhabditis elegans lifespan and motor deficits in combination with roscovitine.

Glycogen synthase kinase 3β (GSK3β) is considered an important element of glycogen metabolism; however, it has many other regulatory roles. Changes in the GSK3β signaling mechanism have been associated with various disorders, such as Alzheimer's disease (AD), type II diabetes, and cancer. Although the effects of GSK3β inhibitors on reducing the pathological effects of AD have been described, an effective inhibitor has not yet been developed. Epibrassinolide (EBR), a brassinosteroid (BR), is structurally similar to mammalian steroid hormones. Our studies have shown that EBR has an inhibitory effect on GSK3β in different cell lines. Roscovitine (ROSC), a cyclin-dependent kinase (CDK) inhibitor, has also been identified as a potential GSK3 inhibitor. Within the scope of this study, we propose that EBR and/or ROSC might have mechanistic action in AD models. To test this hypothesis, we used in vitro models and Caenorhabditis elegans (C. elegans) AD strains. Finally, EBR treatment successfully protected cells from apoptosis and increased the inhibitory phosphorylation of GSK3β. In addition, EBR and/or ROSC treatment had a positive effect on the survival rates of C. elegans strains. More interestingly, the paralysis phenotype of the C. elegans AD model due to Aβ42 toxicity was prevented by EBR and/or ROSC. Our findings suggest that EBR and ROSC administration have neuroprotective effects on both in vitro and C. elegans models via inhibitory GSK3β phosphorylation at Ser9.

Effect of epibrassynolide on the flavonoids content in plant sprouts under stress caused by N-phosphonomethylglycine

The effect of epibrassinolide (EBL) on the content of flavonoids in seedlings of fiber flax (Linum usitatissimum L.) and spring barley (Hordeum vulgare L.) under chemical stress caused by N-phosphonomethylglycine (glyphosate) was studied. The species specificity of the response of the seedlings to the introduction of EBL in a mixture with an inhibitory dose of glyphosate was noted. This specificity is expressed in the suppression of the inhibitory effect of glyphosate on the flavonoids' content in the tissues of fiber flax and the absence of changes in the level of the content of flavonoids in the roots and aerial part of spring barley seedlings.

Epi-Brassinolide Positively Affects Chlorophyll Content and Dark-Reaction Enzymes of Maize Seedlings

Brassinosteroids participate in many physiological processes in plants; however, their regulatory roles on the activities of the enzymes involved in dark phase of photosynthesis remains elusive. In this study, detached leaves and protoplasts of maize seedlings were treated with epi-brassinolide (EBR) and brassinazole followed by the determination of the contents of chlorophyll (a+b) and soluble sugars, and the activity of dark reaction enzymes and the expression of the relevant genes. The results showed that chlorophyll (a+b) content increased by 7.4% under 0.1 μM EBR treatment for 48 h; furthermore, chlorophyll (a+b) content increased by 34% in detached leaves that were continuously soaked in brassinazole. In addition, the transcription levels of glyceraldehyde-3-phosphate dehydrogenase subunit A (GAPA), cytoplasmic FBPase (cyFBPase), ribulose-1,5-bisphosphate carboxylase small subunit (rbcS), phosphoenolpyruvate carboxylase (PEPC), fructose-1,6-bisphosphatase (FBPase), Rubisco activase β subunit (RCAβ), ribulose-l,5-bisphosphate carboxylase large subunit (rbcL), and glutathione reductase (GR) were 96.8%, 48.4%, 79.3%, 41%, 85.6%, 133.3%, 68.8%, and 119.8% higher, respectively, in 0.1 μM EBR than in the control group. The activity of RCA and Rubisco and soluble sugar content increased by 53.4%, 28.7%, and 35.4% under 0.1 μM EBR. Brassinazole inhibits the expression of these genes. However, the transcription level, protein content, and activity of some dark-reaction enzymes cannot be increased at the same time under EBR treatment. These results indicate that the effect of EBR on dark-reaction is mainly in transcription level.

Сравнительный анализ влияния эпибрассинолида и 6-бензиламинопурина на ключевые компоненты глутатионового комплекса в корнях проростков пшеницы в условиях засоления

The study carried out a comparative analysis of the effect of 24 epibrassinolide (EB) and 6-benzylaminopurine (BAP) on the growth and state of the main components of the glutathione system in the roots of wheat seedlings under the action of 2% NaCl, which for the first time revealed the ability of these phytohormones to similarly stabilize stress-induced decrease GSH / GSSG ratio, positively regulate the activity of glutathione reductase and glutathione-S-transferase. A comparable level of protective effect of BAP and EB on root length was revealed. The data obtained indicate that endogenous cytokinins may play the role of hormonal intermediates in the implementation of the protective.

Epibrassinolide activates AKT to trigger autophagy with polyamine metabolism in SW480 and DLD-1 colon cancer cell lines.

Epibrassinolide (EBR), a plant-derived polyhydroxylated derivative of 5α-cholestane, structurally shows similarities to animal steroid hormones. According to the present study, EBR treatment triggered a significant stress response via activating ER stress, autophagy, and apoptosis in cancer cells. EBR could also increase Akt phosphorylation in vitro. While the activation of Akt resulted in cellular metabolic activation in normal cells to proceed with cell survival, a rapid stress response was induced in cancer cells to reduce survival. Therefore, Akt as a mediator of cellular survival and death decision pathways is a crucial target in cancer cells. In this study, we determined that EBR induces stress responses through activating Akt, which reduced the mTOR complex I (mTORC1) activation in SW480 and DLD-1 colon cancer cells. As a consequence, EBR triggered macroautophagy and led to lipidation of LC3 most efficiently in SW480 cells. The cotreatment of spermidine (Spd) with EBR increased lipidation of LC3 synergistically in both cell lines. We also found that EBR promoted polyamine catabolism in SW480 cells. The retention of polyamine biosynthesis was remarkable following EBR treatment. We suggested that EBR-mediated Akt activation might determine the downstream cellular stress responses to induce autophagy related to polyamines.

24-Epi Brassinolidin, Sıcaklık Stresi Koşullarında Parus ve Gaviota Çilek Çeşitlerinin Bazı Biyokimyasal Özellikleri Üzerine Etkisi

The study was arranged as factorial experiment in a completely randomized design with three applications of cultivar (Parus and Gaviota), 24- Epi brassinolide concentrations (0, 1 and 2 mgl-1) and temperature (normal and stress) as three replications. Some of the measuring characteristics showed that there was a significant difference among the treatments. Under heat stress conditions, foliar application of 24- Epi brassinolide at 1 mgl-1 concentration increased the amount of catalase and superoxide dismutase activity in leaves of Parus cultivar. Both cultivars fruits showed the highest total soluble solid contents in treatment 24- Epi brassinolide spraying at 2 mgl-1 concentrations under normal temperature. The highest total phenolics was in Gaviota cultivar treated with 24- Epi brassinolide spraying at 2 mgl-1 concentrations under normal temperature. Both cultivars had the lowest flavonoid in treatments without 24- Epi brassinolide and with 24- Epi brassinolide at 2 mgl-1 concentrations under heat stress conditions. In Gaviota cultivar, application of high concentration of 24- Epi brassinolide (2 mgl-1) prevented the reduction of total anthocyanin under heat stress conditions.

24-Epibrassinolide Alleviates the Injurious Effects of Cr(VI) Toxicity in Tomato Plants: Insights into Growth, Physio-Biochemical Attributes, Antioxidant Activity and Regulation of Ascorbate–Glutathione and Glyoxalase Cycles

Brassinosteroids (BRs) are well-ascertained growth regulators that play prime roles in alleviation of a stress in plants. The current investigation determined the impact of epibrassinolide (EBR) applied as seed pretreatment on growth attributes, physiological attributes and antioxidant potential of tomato plants grown under Cr(VI) metal stress. Applications of EBR were found to be effective in improving growth of control as well as Cr-stressed plants in terms of lengths of shoot and root and their dry weights. Of the physiological parameters, stomatal conductance was the most sensitive to chromium exposure exhibiting 72.15% decline, while photosynthetic rate decreased to 33.16%. Chromium stress led to decline in non-enzymatic antioxidants like GSH by 41.85% and in total flavonoid by 69.48%. Application of EBR modulated more significantly the titres of antioxidants (glutathione, ascorbic acid, total flavonoids and activities of antioxidant enzymes (ascorbate peroxidase, catalase, superoxide dismutase, glutathione-S-transferase and glutathione reductase) as well as proline and glycine betaine in Cr-stressed plants compared to those in plants receiving no supply of EB. Diminution of Cr stress by EBR was also maintained by higher values of stress indices, such as flavonoids, photosynthetic pigments and reduction in malondialdehyde and H2O2 levels in the Cr-treated plants than those in the controls. Restricted production of ROS and improved quenching of ROS were also recorded due to EBR application under Cr stress. At the same time, insignificant reduction in uptake of Cr was noticed due to application of EBR in leaves compared to that in roots of Cr-stressed plants. Overall, our results reveal that application of EBR can effectively act as a growth stimulant in plants subjected to Cr stress. Therefore, it can be conjectured that the interaction of 24-epibrassinolide remodulates the physiological, metabolic and defence system of the tomato thriving under chromium stress by equilibrating the Cr accumulation.

Role of l-Cysteine Desulfhydrase in Epibrassinolide-Induced Tolerance to Boron Toxicity in Pepper (Capsicum annuum L.) Plants

Although the effect of epibrassinolide (EBL) on plants under boron (B) toxicity has been studied, the participation of l-cysteine desulfhydrase (l-DES) in EBL-induced tolerance to boron toxicity needs to be uncovered. Therefore, a glasshouse trial was carried out to evaluate what extent l-DES participates in EBL-improved B stress tolerance of pepper plants. Before starting B treatment, 0.5 µM 24-epibrassinolide (EBL) or deionized water (for control treatment) was sprayed to the 10-day-old pepper seedlings every two days for 10 days. Then pepper seedlings were subjected to B toxicity (2.0 mM) in nutrient solution. After starting B treatment, inhibitor of l-DES, 2.0 mM dl-propargylglycine (PAG) was sprayed to plant twice a week. Boron toxicity caused a marked suppression in dry biomass, leaf water potential, leaf relative water, chlorophyll a, chlorophyll b, photosystem II maximum quantum efficiency (Fv/Fm), ascorbate (AsA) and glutathione (GSH) in the pepper seedlings. In contrast, it enhanced the accumulation of malondialdehyde (MDA), hydrogen peroxide (H2O2), electrolyte leakage (EL), free proline, catalase, superoxide dismutase, peroxidase, endogenous hydrogen sulphide (H2S) and l-DES activity. In contrast, foliar spray of EBL promoted key growth characteristics, water relations, levels of free proline and activities of various enzymatic and non-enzymatic antioxidants as well as endogenous H2S and l-DES activity, but it suppressed H2O2 and MDA contents as well as membrane leakage. Foliar application of EBL caused a marked decrease in tissue B concentration but an increase in the contents of leaf Ca2+, K+ and N. Moreover, inhibitor of l-DES, PAG was sprayed to stressed and control plants to assess the role of l-DES in EBL-improved B stress tolerance. Application of PAG inverted the affirmative effects of EBL on oxidative stress and antioxidant defence system by reducing both endogenous H2S and l-DES activities, suggesting that L-DES participates in EBL-induced B toxicity tolerance of pepper plants.

Epibrassinolide-induced autophagy occurs in an Atg5-independent manner due to endoplasmic stress induction in MEF cells.

Epibrassinolide (EBR), a polyhydroxysteroid belongs to plant growth regulator family, brassinosteroids and has been shown to have a similar chemical structure to mammalian steroid hormones. Our findings indicated that EBR could trigger apoptosis in cancer cells via induction of endoplasmic reticulum (ER) stress, caused by protein folding disturbance in the ER. Normal cells exhibited a remarkable resistance to EBR treatment and avoid from apoptotic cell death. The unfolded protein response clears un/misfolded proteins and restore ER functions. When stress is chronic, cells tend to die due to improper cellular functions. To understand the effect of EBR in non-malign cells, mouse embryonic fibroblast (MEF) cells were investigated in detail for ER stress biomarkers, autophagy, and polyamine metabolism in this study. Evolutionary conserved autophagy mechanism is a crucial cellular process to clean damaged organelles and protein aggregates through lysosome under the control of autophagy-related genes (ATGs). Cells tend to activate autophagy to promote cell survival under stress conditions. Polyamines are polycationic molecules playing a role in the homeostasis of important cellular events such as cell survival, growth, and, proliferation. The administration of PAs has been markedly extended the lifespan of various organisms via inducing autophagy and inhibiting oxidative stress. Our data indicated that ER stress is induced following EBR treatment in MEF cells as well as MEF Atg5-/- cells. In addition, autophagy is activated following EBR treatment by targeting PI3K/Akt/mTOR in wildtype (wt) cells. However, EBR-induced autophagy targets ULK1 in MEF cells lacking Atg5 expression. Besides, EBR treatment depleted the PA pool in MEF cells through the alterations of metabolic enzymes. The administration of Spd with EBR further increased autophagic vacuole formation. In conclusion, EBR is an anticancer drug candidate with selective cytotoxicity for cancer cells, in addition the induction of autophagy and PA metabolism are critical for responses of normal cells against EBR.