Brassinosteroids Research Articles

Far-red light inhibits lateral bud growth mainly through enhancing apical dominance independently of strigolactone synthesis in tomato.

The ratio of red light to far-red light (R:FR) is perceived by light receptors and consequently regulates plant architecture. Regulation of shoot branching by R:FR ratio involves plant hormones. However, the roles of strigolactone (SL), the key shoot branching hormoneand the interplay of different hormones in the light regulation of shoot branching in tomato (Solanum lycopersicum) are elusive. Here, we found that defects in SL synthesis genes CAROTENOID CLEAVAGE DIOXYGENASE 7 (CCD7) and CCD8 in tomato resulted in more lateral bud growth but failed to reverse the FR inhibition of lateral bud growth, which was associated with increased auxin synthesis and decreased synthesis of cytokinin (CK) and brassinosteroid (BR). Treatment of auxin also inhibited shoot branching in ccd mutants. However, CK released the FR inhibition of lateral bud growth in ccd mutants, concomitant with the upregulation of BR synthesis genes. Furthermore, plants that overexpressed BR synthesis gene showed more lateral bud growth and the shoot branching was less sensitive to the low R:FR ratio. The results indicate that SL synthesis is dispensable for light regulation of shoot branching in tomato. Auxin mediates the response to R:FR ratio to regulate shoot branching by suppressing CK and BR synthesis.

Single cell RNA-seq in phytohormone signaling: a promising future.

Phytohormone signaling regulates plant growth and development. Single cell RNA sequencing (scRNA-seq) provides unprecedented opportunities to decipher hormone-mediated spatiotemporal gene regulatory networks. In a recent study, Nolan et al. used time-series scRNA-seq to identify the cortex as a key site for brassinosteroid (BR)-mediated gene expression and revealed a signaling network during cell phase transition.

Morphological, physio-biochemical, and molecular indications of heat stress tolerance in cucumber

Global warming is a critical challenge limiting crop productivity. Heat stress during cucumber growing stages caused deterioration impacts on the flowering, fruit, and yield stages. In this study, “inbred line 1 and hybrid P1 × P2” (heat-tolerant) and “Barracuda” (heat-sensitive) were utilized to determine the heat tolerance in summer season. The heat injury index was used to exhibit the heat tolerance performance. The heat injury index for heat tolerant (HT) genotypes, on leaves (HIIL%) and female flowers (HIIF%), was less than 25 and 15 % in HT, compared to heat sensitive (HS) was more than 75 and 85%, respectively. Moreover, the content of leaf chlorophyll, proline, brassinosteroid (BRs), abscisic acid content (ABA), the activity of catalase (CAT, EC 1.11. 1.6), peroxidase (POD, EC 1.11.1.7) and superoxide dismutase (SOD, EC 1.15.1.1) increased with the heat stress responses in HT plants. Expression pattern analyses of eight genes, related to POD (CSGY4G005180 and CSGY6G015230), SOD (CSGY4G010750 and CSGY1G026400), CAT (CsGy4G025230 and CsGy4G025240), and BR (CsGy6G029150 and CsGy6G004930) showed a significant increase in HT higher than in HS plants. This study furnishes valuable markers for heat tolerance genotypes breeding in cucumber and provides a basis for understanding heat-tolerance mechanisms.

Mutual dependence of brassinosteroid homeostasis and plasmodesmata permeability

Brassinosteroids (BRs) are exceptional phytohormones: they do not undergo a long-distance transport between plant organs. However, the mechanism of short-distance (intercellular) transport of BRs remains poorly understood. Recently, Wang et al. provided a novel insight into the mutual dependence of BR homeostasis, their intercellular transport, and plasmodesmata permeability.

Postharvest 24-epibrassinolide treatment improves chilling resistance of peach fruit via PpHDT1 modulating brassinosteroid metabolism

Brassinosteroids (BRs) exhibit a positive effect on facilitating chilling resistance in fruits and vegetables. However, the change and regulatory mechanism of BR metabolism in fruits and vegetables are poorly understood. This study aimed to explore the underlying relationship among chilling injury (CI), BR metabolism and regulatory factor PpHDT1. The results showed that exogenous 24-epibrassinolide (EBR) retarded peaches CI, reduced endogenous brassinolide (BL) accumulation, repressed the transcriptions of BR synthesis-related genes, promoted expression of BR signal-related genes. The results of molecular assays in vivo demonstrated that PpHDT1 down-regulated BR synthesis gene PpDWF4 and up-regulated BR signal transduction gene PpBZR1. Moreover, EBR treatment enhanced PpHDT1 expression, revealing that EBR treatment might alleviate peaches CI through PpHDT1 modulating BL metabolism and signal pathway. Our study provides a new insight into the underlying mechanism of EBR on regulating chilling resistance in postharvest peaches.

Brassinosteroid enhances salt tolerance via S-nitrosoglutathione reductase and nitric oxide signaling pathway in mangrove Kandelia obovata.

Brassinosteroid (BR) has been shown to modulate plant tolerance to various stresses. S-nitrosoglutathione reductase (GSNOR) is involved in the plant response to environment stress by fine-turning the level of nitric oxide (NO). However, whether GSNOR is involved in BR-regulated Na+ /K+ homeostasis to improve the salt tolerance in halophyte is unknown. Here, we firstly reported that high salinity increases the expression of BR-biosynthesis genes and the endogenous levels of BR in mangrove Kandelia obovata. Then, salt-induced BR triggers the activities and gene expressions of GSNOR and antioxidant enzymes, thereafter decrease the levels of malondialdehyde, hydrogen peroxide. Subsequently, BR-mediated GSNOR negatively regulates NO contributions to the reduction of reactive oxygen species generation and induction of the gene expression related to Na+ and K+ transport, leading to the decrease of Na+ /K+ ratio in the roots of K. obovata. Finally, the applications of exogenous BR, NO scavenger, BR biosynthetic inhibitor and GSNOR inhibitor further confirm the function of BR. Taken together, our result provides insight into the mechanism of BR in the response of mangrove K. obovata to high salinity via GSNOR and NO signaling pathway by reducing oxidative damage and modulating Na+ /K+ homeostasis.

Physiological Analysis and Genetic Mapping of Short Hypocotyl Trait in Brassica napus L.

Hypocotyl length is a botanical trait that affects the cold tolerance of Brassica napus L. (B. napus). In this study, we constructed an F2 segregating population using the cold-resistant short hypocotyl variety '16VHNTS158' and the cold-sensitive long hypocotyl variety 'Tianyou 2288' as the parents, and BSA-seq was employed to identify candidate genes for hypocotyl length in B. napus. The results of parental differences showed that the average hypocotyl lengths of '16VHNTS158' and 'Tianyou 2288' were 0.41 cm and 0.77 cm at the 5~6 leaf stage, respectively, after different low-temperature treatments, and '16VHNTS158' exhibited lower relative ion leakage rates compared to 'Tianyou 2288'. The contents of indole acetic acid (IAA), gibberellin (GA), and brassinosteroid (BR) in hypocotyls of '16VHNTS158' and 'Tianyou 2288' increased with decreasing temperatures, but the IAA and GA contents were significantly higher than those of 'Tianyou 2288', and the BR content was lower than that of 'Tianyou 2288'. The genetic analysis results indicate that the genetic model for hypocotyl length follows the 2MG-A model. By using SSR molecular markers, a QTL locus associated with hypocotyl length was identified on chromosome C04. The additive effect value of this locus was 0.025, and it accounted for 2.5% of the phenotypic variation. BSA-Seq further localized the major effect QTL locus on chromosome C04, associating it with 41 genomic regions. The total length of this region was 1.06 Mb. Within this region, a total of 20 non-synonymous mutation genes were identified between the parents, and 26 non-synonymous mutation genes were found within the pooled samples. In the reference genome of B. napus, this region was annotated with 24 candidate genes. These annotated genes are predominantly enriched in four pathways: DNA replication, nucleotide excision repair, plant hormone signal transduction, and mismatch repair. The findings of this study provide a theoretical basis for cloning genes related to hypocotyl length in winter rapeseed and their utilization in breeding.

Phytohormonal modulation of the drought stress in soybean: outlook, research progress, and cross-talk.

Phytohormones play vital roles in stress modulation and enhancing the growth of plants. They interact with one another to produce programmed signaling responses by regulating gene expression. Environmental stress, including drought stress, hampers food and energy security. Drought is abiotic stress that negatively affects the productivity of the crops. Abscisic acid (ABA) acts as a prime controller during an acute transient response that leads to stomatal closure. Under long-term stress conditions, ABA interacts with other hormones, such as jasmonic acid (JA), gibberellins (GAs), salicylic acid (SA), and brassinosteroids (BRs), to promote stomatal closure by regulating genetic expression. Regarding antagonistic approaches, cytokinins (CK) and auxins (IAA) regulate stomatal opening. Exogenous application of phytohormone enhances drought stress tolerance in soybean. Thus, phytohormone-producing microbes have received considerable attention from researchers owing to their ability to enhance drought-stress tolerance and regulate biological processes in plants. The present study was conducted to summarize the role of phytohormones (exogenous and endogenous) and their corresponding microbes in drought stress tolerance in model plant soybean. A total of n=137 relevant studies were collected and reviewed using different research databases.

BBX21 Integrates Brassinosteroid Biosynthesis andSignaling inthe Inhibition ofHypocotyl Growth under Shade.

B-Box-containing zinc finger transcription factors (BBX) are involved in light-mediated growth, affecting processes such as hypocotyl elongation in Arabidopsis thaliana. However, the molecular and hormonal framework that regulates plant growth through BBX proteins is incomplete. Here, we demonstrate that BBX21 inhibits the hypocotyl elongation through the brassinosteroid (BR) pathway. BBX21 reduces the sensitivity to 24-epiBL, a synthetic active BR, principally at very low concentrations in simulated shade. The biosynthesis profile of BRs showed that two active BR-brassinolide and 28-homobrassinolide-and 8 of 11 intermediates can be repressed by BBX21 under white light (WL) or simulated shade. Furthermore, BBX21 represses the expression of CYTOCHROME P450 90B1 (DWF4/CYP90B1), BRASSINOSTEROID-6-OXIDASE 1 (BR6OX1, CYP85A1) and BR6OX2 (CYP85A2) genes involved in the BR biosynthesis in WL while specifically promoting DWF4 and PHYB ACTIVATION TAGGED SUPPRESSOR 1 (CYP2B1/BAS1) expression in WL supplemented with far-red (WL + FR), a treatment that simulates shade. In addition, BBX21 represses BR signaling genes, such as PACLOBUTRAZOL RESISTANCE1 (PRE1), PRE3 and ARABIDOPSIS MYB-LIKE 2 (MYBL2), and auxin-related and expansin genes, such as INDOLE-3-ACETIC ACID INDUCIBLE 1 (IAA1), IAA4 and EXPANSIN 11 in short-term shade. By a genetic approach, we found that BBX21 acts genetically upstream of BRASSINAZOLE-RESISTANT 1 (BZR1) for the promotion of DWF4 and BAS1 gene expression in shade. We propose that BBX21 integrates the BR homeostasis and shade-light signaling, allowing the fine-tuning of hypocotyl elongation in Arabidopsis.

Influence of Exogenous 24-Epicasterone on the Hormonal Status of Soybean Plants.

Brassinosteroids (BRs) are key phytohormones involved in the regulation of major processes of cell metabolism that guide plant growth. In the past decades, new evidence has made it clear that BRs also play a key role in the orchestration of plant responses to many abiotic and biotic stresses. In the present work, we analyzed the impact of foliar treatment with 24-epicastasterone (ECS) on the endogenous content of major phytohormones (auxins, salicylic acid, jasmonic acid, and abscisic acid) and their intermediates in soybean leaves 7 days following the treatment. Changes in the endogenous content of phytohormones have been identified and quantified by LC/MS. The obtained results point to a clear role of ECS in the upregulation of auxin content (indole-3-acetic acid, IAA) and downregulation of salicylic, jasmonic, and abscisic acid levels. These data confirm that under optimal conditions, ECS in tested concentrations of 0.25 µM and 1 µM might promote growth in soybeans by inducing auxin contents. Benzoic acid (a precursor of salicylic acid (SA)), but not SA itself, has also been highly accumulated under ECS treatment, which indicates an activation of the adaptation strategies of cell metabolism to possible environmental challenges.

Vacuolar H+-ATPase and BZR1 form a feedback loop to regulate the homeostasis of BR signaling in Arabidopsis

Brassinosteroid (BR) is a vital plant hormone that regulates plant growth and development. BRASSINAZOLE RESISTANT 1 (BZR1) is a key transcription factor in BR signaling, and its nucleocytoplasmic localization is crucial for BR signaling. However, the mechanisms that regulate BZR1 nucleocytoplasmic distribution and thus the homeostasis of BR signaling remain largely unclear. The vacuole is the largest organelle in mature plant cells and plays a key role in maintenance of cellular pH, storage of intracellular substances, and transport of ions. In this study, we uncovered a novel mechanism of BR signaling homeostasis regulated by the vacuolar H+-ATPase (V-ATPase) and BZR1 feedback loop. Our results revealed that the vha-a2 vha-a3 mutant (vha2, lacking V-ATPase activity) exhibits enhanced BR signaling with increased total amount of BZR1, nuclear-localized BZR1, and the ratio of BZR1/phosphorylated BZR1 in the nucleus. Further biochemical assays revealed that VHA-a2 and VHA-a3 of V-ATPase interact with the BZR1 protein through a domain that is conserved across multiple species. VHA-a2 and VHA-a3 negatively regulate BR signaling by interacting with BZR1 and promoting its retention in the tonoplast. Interestingly, a series of molecular analyses demonstrated that nuclear-localized BZR1 could bind directly to specific motifs in the promoters of VHA-a2 and VHA-a3 to promote their expression. Taken together, these results suggest that V-ATPase and BZR1 may form a feedback regulatory loop to maintain the homeostasis of BR signaling in Arabidopsis, providing new insights into vacuole-mediated regulation of hormone signaling.

Regulatory networks of the F-box protein FBX206 and OVATE family proteins modulate brassinosteroid biosynthesis to regulate grain size and yield in rice.

F-box proteins participate in the regulation of many processes, including cell division, development, and plant hormone responses. Brassinosteroids (BRs) regulate plant growth and development by activating core transcriptional and other multiple factors. In rice, OVATE family proteins (OFPs) participate in BR signalling and regulate grain size. Here we identified an F-box E3 ubiquitin ligase, FBX206, that acts as a negative factor in BR signalling and regulates grain size and yield in rice. Suppressed expression of FBX206 by RNAi leads to promoted plant growth and increased grain yield. Molecular analyses showed that the expression levels of BR biosynthetic genes were up-regulated, whereas those of BR catabolic genes were down-regulated in FBX206-RNAi plants, resulting in the accumulation of 28-homoBL, one of the bioactive BRs. FBX206 interacted with OsOFP8, a positive regulator in BR signalling, and OsOFP19, a negative regulator in BR signalling. SCFFBX206 mediated the degradation of OsOFP8 but suppressed OsOFP19 degradation. OsOFP8 interacted with OsOFP19, and the reciprocal regulation between OsOFP8 and OsOFP19 required the presence of FBX206. FBX206 itself was ubiquitinated and degraded, but interactions of OsOFP8 and OsOFP19 synergistically suppressed the degradation of FBX206. Genetic interactions indicated an additive effect between FBX206 and OsOFP8 and epistatic effects of OsOFP19 on FBX206 and OsOFP8. Our study reveals the regulatory networks of FBX206, OsOFP8, and OsOFP19 in BR signalling that regulate grain size and yield in rice.

Identification and characterization of BES1 genes involved in grain size development of Oryza sativa L.

BES1 (BRI1-EMS-SUPPRESSOR1) defines a unique class of plant-specific transcription factors that plays an essential role in response to Brassinosteroids (BRs) signal induction pathways. In our study, we conducted genome-wide scanning and comprehensive characterization of the BES1 gene family in rice and other eukaryotes, leading to valuable findings. Molecular docking experiments showed that all OsBES1 genes in rice could directly bind to BR small molecules. Among the identified genes, OsBES1–4 exhibited a remarkable response as it consistently showed induction upon exposure to various phytohormones after treatment. Further functional verification of OsBES1–4 revealed its impact on grain size. Overexpression of OsBES1–4 resulted in increased grain size, as confirmed by cytological observations showing an increase in cell length and cell number. Moreover, we identified that OsBES1–4 plays a role in rice grain size development by binding to the BR response element in the promoter region of the OsBZR1 gene. Evolutionary analysis indicated differentiation of OsBES1–4 between indica and japonica rice varieties, suggesting natural selection during the domestication process of cultivated rice. Therefore, we conclude that OsBES1–4 plays a crucial role in regulating rice grain size and has the potential to be an important target in rice breeding programs, and haplotype analysis found that all OsBES1 genes were associated with grain size development, either thousand-grain weight, grain length, or grain width. Overall, these findings suggest that the BES1 genes are involved in the regulation of grain size development in rice, and the utilization of SNPs in the OsBES1–4 gene promoter could be a favorable option for distinguishing indica and japonica.

28-Homobrassinolide Primed Seed Improved Lead Stress Tolerance in Brassica rapa L. through Modulation of Physio-Biochemical Attributes and Nutrient Uptake.

Brassinosteroids (BRs) influence a variety of physiological reactions and alleviate different biotic and abiotic stressors. Turnip seedlings were grown with the goal of further exploring and expanding their function in plants under abiotic stress, particularly under heavy metal toxicity (lead stress). This study's objective was to ascertain the role of applied 28-homobrassinolide (HBL) in reducing lead (Pb) stress in turnip plants. Turnip seeds treated with 1, 5, and 10 µM HBL and were grown-up in Pb-contaminated soil (300 mg kg-1). Lead accumulation reduces biomass, growth attributes, and various biochemical parameters, as well as increasing proline content. Seed germination, root and shoot growth, and gas exchange characteristics were enhanced via HBL treatment. Furthermore, Pb-stressed seedlings had decreased total soluble protein concentrations, photosynthetic pigments, nutrition, and phenol content. Nonetheless, HBL increased chlorophyll a and chlorophyll b levels in plant, resulting in increased photosynthesis. As a result, seeds treated with HBL2 (5 µM L-1) had higher nutritional contents (Mg+2, Zn+2, Na+2, and K+1). HBL2-treated seedlings had higher DPPH and metal tolerance indexes. This led to the conclusion that HBL2 effectively reduced Pb toxicity and improved resistance in lead-contaminated soil.

GhSMO2-2 is regulated by brassinosteroid signal and involved in cotton fiber elongation via influencing phytosterol and sphingolipid biosynthesis

Cotton fiber cell is an extremely elongated single cell and is regarded as an ideal material to study the growth and development of plant cell. Phytohormone brassinosteroids (BRs) play crucial roles in fiber cell development. However, its action mechanism in fiber growth is largely unknown. In this study, we identified a homologue of Arabidopsis SMO2–2 (Sterol C-4α Methyl Oxidase), GhSMO2–2, in upland cotton (Gossypium hirsutum L.), which predominantly expressed in fiber cell and peaked at the rapid elongation stage, and responded to BR signal. The GhBES1, a transcription factor in BR signaling could directly bind to the promoter of GhSMO2–2 and promoted its expression. Overexpression of GhSMO2–2 significantly promoted fiber cell elongation and phytosterol synthesis in cotton, and elevated some sphingolipid species that was important for fiber elongation. On the contrary, down-regulating GhSMO2–2 suppressed fiber elongation and blocked these chemicals accumulation. These results indicated that GhSMO2–2 is an important gene involved in fiber cell elongation, and is valuable for genetic engineering to improve fiber quality and yield. Taken together, our study revealed that BR regulated fiber cell elongation by influencing phytosterol and sphingolipid biosynthesis, the key components of membrane lipid raft and provided a new clue for further revealing the function and mechanism of phytosterols, sphingolipids, and BRs in plant cell development.

Brassinosteroid modulates ethylene synthesis and antioxidant metabolism to protect rice (Oryza sativa) against heat stress-induced inhibition of source‒sink capacity and photosynthetic and growth attributes

This study presents an exploration of the efficacy of brassinosteroids (BRs) and ethylene in mediating heat stress tolerance in rice (Oryza sativa). Heat is one of the major abiotic factors that prominently deteriorates rice production by influencing photosynthetic efficiency, source‒sink capacity, and growth traits. The application of BR (0.5 mM) and ethylene (200 μl l−1) either individually and/or in combination was found to alleviate heat stress-induced toxicity by significantly improving photosynthesis, source‒sink capacity and defense systems; additionally, it reduced the levels of oxidative stress markers and ethylene formation. The study revealed the positive influence of BR in promoting plant growth responses under heat stress through its interplay with ethylene biosynthesis and enhanced plant defense systems. Interestingly, treatment with the ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG) substantiated that BR application to heat-stressed rice plants enhanced ethylene-dependent pathways to counteract the underlying adversities. Thus, BR action was found to be mediated by ethylene to promote heat tolerance in rice. The present study sheds light on the potential tolerance mechanisms which can ensure rice sustainability under heat stress conditions.

TaBZR1 enhances wheat salt tolerance via promoting ABA biosynthesis and ROS scavenging

Brassinosteroids (BRs) are vital plant steroid hormones involved in numerous aspects of plant life including growth, development, and responses to various stresses. However, the underlying mechanisms of how BR regulates abiotic stress responses in wheat (Triticum aestivum L.) remain to be elucidated. Here, we find that BR signal core transcription factor BRASSINAZOLE-RESISTANT1 (TaBZR1) is significantly up-regulated by salt treatment. Overexpression of Tabzr1-1D (a gain-of-function TaBZR1 mutant protein) improves wheat salt tolerance. Furthermore, we show that TaBZR1 binds directly to the G-box motif in the promoter of ABA biosynthesis gene TaNCED3 to activate its expression and promotes ABA accumulation. Moreover, TaBZR1 associates with the promoters of ROS-scavenging genes TaGPX2 and TaGPX3 to activate their expression. Taken together, our results elucidate that TaBZR1 improves salt-stress tolerance by activating some genes involved in the biosynthesis of ABA and ROS scavenging in wheat, which gives us a new strategy to improve the salt tolerance of wheat.

Practical aspects of brassinosteroids in drought stress protection and its usage in agriculture

Brassinosteroids (BRs) represents a new group of phytohormones. They contribute to regulation of plants growth and development, act as regulators of plant processes as seed germination, elongation growth, photomorphogenesis and photosynthesis. They are critical in response to environmental and biotic stresses like: heat, salinity, heavy metal pollution or pathogenic microorganisms. Drought stress occurs during deficiency of water in the plant environment. Lack of water in plant medium highly affects the plant development. It comes to plant processes disorders and abnormal development of plants. Long-term drought stress may cause the death of plant. Drought stress occurs in agriculture. Hence, there is a need to protect plants against its effect. Numerous reports indicate that BRs are beneficial to plants during stress, including drought. In the following research, the role of BRs in plants and usefulness of these growth regulators during stresses, especially drought, was explained. Additionally, the previous use in agriculture was described.

DWARF AND LOW-TILLERING 2 functions in brassinosteroid signaling and controls plant architecture and grain size in rice.

Brassinosteroids (BRs) are a class of steroid phytohormones that control various aspects of plant growth and development. Several transcriptional factors (TFs) have been suggested to play roles in BR signaling. However, their possible relationship remains largely unknown. Here, we identified a rice mutant dwarf and low-tillering 2 (dlt2) with altered plant architecture, increased grain width, and reduced BR sensitivity. DLT2 encodes a GIBBERELLIN INSENSITIVE (GAI)-REPRESSOR OF GAI (RGA)-SCARECROW (GRAS) TF that is mainly localized in the nucleus and has weak transcriptional activity. Our further genetic and biochemical analyses indicate that DLT2 interacts with two BR-signaling-related TFs, DLT and BRASSINAZOLE-RESISTANT 1, and probably modulates their transcriptional activity. These findings imply that DLT2 is implicated in a potentially transcriptional complex that mediates BR signaling and rice development and suggests that DLT2 could be a potential target for improving rice architecture and grain morphology. This work also sheds light on the role of rice GRAS members in regulating numerous developmental processes.

Exploring the recuperative potential of brassinosteroids and nano-biochar on growth, physiology, and yield of wheat under drought stress

Drought stress as a result of rapidly changing climatic conditions has a direct negative impact on crop production especially wheat which is the 2nd staple food crop. To fulfill the nutritional demand under rapidly declining water resources, there is a dire need to adopt a precise, and efficient approach in the form of different amendments. In this regard, the present study investigated the impact of nano-biochar (NBC) and brassinosteroids (BR) in enhancing the growth and productivity of wheat under different drought stress conditions. The field study comprised different combinations of amendments (control, NBC, BR, and NBC + BR) under three irrigation levels (D0, D1 and D2). Among different treatments, the synergistic approach (NBC + BR) resulted in the maximum increase in different growth and yield parameters under normal as well as drought stress conditions. With synergistic approach (NBC + BR), the maximum plant height (71.7 cm), spike length (17.1), number of fertile tillers m–2 (410), no. of spikelets spike–1 (19.1), no. of grains spike–1 (37.9), 1000 grain weight (37 g), grain yield (4079 kg ha–1), biological yield (10,502 kg ha–1), harvest index (43.5). In the case of physiological parameters such as leaf area index, relative water contents, chlorophyll contents, and stomatal conductance were maximally improved with the combined application of NBC and BR. The same treatment caused an increase of 54, 10, and 7% in N, P, and K contents in grains, respectively compared to the control treatment. Similarly, the antioxidant response was enhanced in wheat plants under drought stress with the combined application of NBC and BR. In conclusion, the combined application of NBC and BR caused a significant increase in the growth, physiological and yield attributes of wheat under drought stress.