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Brassinosteroids (BRs) regulate plant growth and stress responses via the BES1/BZR1 family of transcription factors, which regulate the expression of thousands of downstream genes. BRs are involved in the response to drought, however the mechanistic understanding of interactions between BR signalling and drought response remains to be established. Here we show that transcription factor RD26 mediates crosstalk between drought and BR signalling. When overexpressed, BES1 target gene RD26 can inhibit BR-regulated growth. Global gene expression studies suggest that RD26 can act antagonistically to BR to regulate the expression of a subset of BES1-regulated genes, thereby inhibiting BR function. We show that RD26 can interact with BES1 protein and antagonize BES1 transcriptional activity on BR-regulated genes and that BR signalling can also repress expression of RD26 and its homologues and inhibit drought responses. Our results thus reveal a mechanism coordinating plant growth and drought tolerance.

Abstract: Found that the existing routing algorithms in wireless sensor networks do not consider the selection of the optimal path between cluster heads and the sink node, which lead to the problem of excessive energy consumption, so we propose uneven clustering dynamic routing algorithm based on greedy optimization. The algorithm considers residual energy and the distance between nodes and sink node as the election of the clusters, and then generates minimum spanning tree to find the optimal transmission paths by greedy algorithm, and ultimately transmit and forward the collected data through multi-hop routing. Electing cluster heads can balance energy consumption of nodes in the clusters by considering residual energy and the distance between cluster heads and sink node, and generating minimum spanning tree to reduce energy consumption on the transmission paths and extend the life cycle of the entire network. Theoretical analysis and experimental results show that the algorithm is better than the existing LEACH and EEUC algorithms. [Copyright &y& Elsevier]

Maize yield is limited by water deficit in the arid and semiarid regions of China. Conserving water and enhancing crop water productivity are inevitable requirements for the sustainable development of water efficient agriculture. Plant growth regulators (PGRs) play important roles in maize water stress tolerance. In this study, we investigated the effect of plant growth regulator-brazide, a functional analog of brassinolide (BR), on maize water stress resistance through a two-year (2020–2021) field experiment. The experiment included four water treatments (I100: 4012 m3 ha−1; I80: 3210 m3 ha−1; I60: 2407 m3 ha−1; I40: 1605 m3 ha−1), four PGR concentrations (CK: water; Bra: 0.1 μmol L−1 14-hydroxylated brassinosteroid; B1: 0.1 μmol L−1 brazide; B2: 1 μmol L−1 brazide; B3: 10 μmol L−1 brazide). The results showed that deficit irrigation (I60 and I40) decreased soil water content (SWC), photosynthetic rate (Pn), leaf area index (LAI), aboveground biomass (AB) and yield, but improved crop water productivity (WP c). Under deficit irrigation conditions, 1 μmol L−1 brazide application also increased dry matter accumulation and grain yield, a result attributed to improvement of the photosynthetic rate and increases in the root bleeding saps, water productivity. 1 μmol L−1 Brazide application reduced bare tip length, increasing kernel number per ear, thereby increased the yield of I60 and I40 by 15.1% and 11.4% (p ≤ 0.05; 2020), 16.4% and 20.4% (p ≤ 0.001; 2021), respectively. Path analysis showed brazide improved final yields by increasing thousand grain weight (TGW), photosynthetic rate (Pn) and WP c under deficit irrigation. The increase in TGW with brazide treatment was primarily attributed to the increase of Pn. Overall, Brazide increased maize drought resistance mainly by increasing Pn and WP c , with 1 μmol L−1 brazide as an optimal concentration. • A new plant growth regulator, Brazide, was evaluated in maize. • Brazide increased photosynthetic rate and WUE under deficit irrigation. • Application of brazide improved maize growth and grain yield under deficit irrigation. • 1 μmol L−1 brazide as an optimal concentration for maize in arid region of Northwest China. [ABSTRACT FROM AUTHOR]

Summary Plants encounter a variety of stresses and must fine-tune their growth and stress-response programs to best suit their environment. BES1 functions as a master regulator in the brassinosteroid (BR) pathway that promotes plant growth. Here, we show that BES1 interacts with the ubiquitin receptor protein DSK2 and is targeted to the autophagy pathway during stress via the interaction of DSK2 with ATG8, a ubiquitin-like protein directing autophagosome formation and cargo recruitment. Additionally, DSK2 is phosphorylated by the GSK3-like kinase BIN2, a negative regulator in the BR pathway. BIN2 phosphorylation of DSK2 flanking its ATG8 interacting motifs (AIMs) promotes DSK2-ATG8 interaction, thereby targeting BES1 for degradation. Accordingly, loss-of-function dsk2 mutants accumulate BES1, have altered global gene expression profiles, and have compromised stress responses. Our results thus reveal that plants coordinate growth and stress responses by integrating BR and autophagy pathways and identify the molecular basis of this crosstalk. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the impact of varying the formulation of a specific peptide hydrogel (PepGel) on the release kinetics of rhBMP-2 in vitro. Three PepGel formulations were assessed: (1) 50% v / v (peptides volume/total volume) PepGel, where synthetic peptides were mixed with crosslinking reagents and rhBMP-2 solution; (2) 67% v / v PepGel; (3) 80% v / v PepGel. Each sample was loaded with 12 µg of rhBMP-2 and incubated in PBS. Released rhBMP-2 was quantified by ELISA at 1 h, 6 h, and 1, 2, 4, 7, 10, 14, and 21 days. To explore how PepGel formulations influence rhBMP-2 release, the gel porosities, swelling ratios, and mechanical properties of the three PepGel formulations were quantitatively analyzed. The results showed that rhBMP-2 encapsulated with 50% v / v PepGel exhibited a sustained release over the 21-day experiment, while the 67% and 80% v / v PepGels demonstrated significantly lower rhBMP-2 release rates compared to the 50% formulation after day 7. Higher histological porosity of PepGel was significantly correlated with increased rhBMP-2 release rates. Conversely, the swelling ratio and elastic modulus of the 50% v / v PepGel were significantly lower than that of the 67% and 80% v / v formulations. In conclusion, this study indicates that varying the formulation of crosslinked PepGel can control rhBMP-2 release rates in vitro by modulating gel porosity, swelling ratio, and mechanical properties. Encapsulation with 50% v / v PepGel offers a sustained rhBMP-2 release pattern in vitro; if replicated in vivo, this could mitigate the adverse effects associated with burst release of rhBMP-2 in clinical applications.

HBP-A is the main active component of a traditional Chinese medicine Huaizhen Yanggan Capsule, for the remarkable treatment of knee osteoarthritis (KOA). This study aimed to elucidate the ameliorative effect of HBP-A on meniscus hypertrophy and mineralisation in KOA and the molecular mechanism of its action. An Hartley guinea pig model of KOA that underwent anterior cruciate ligament transection (ACLT) and a model of rat primary meniscus fibrochondrocytes (PMFs) were used to investigate the ameliorative effect of HBP-A on meniscal hypertrophy and calcification and its signal transduction mechanism of action. The results show that Guinea pig's meniscus width, as well as the area of meniscus calcification and meniscus and articular cartilage injury score, were significantly reduced in the HBP-A intervention group compared to the ACLT group. The expression levels of mtrix metalloproteinase 13 (MMP13), runt-related transcription factor 2 (Runx2), Indian hedgehog (Ihh), alkaline phosphatase (ALP), and ankylosis homologue (ANKH) at the protein and gene level significantly decreased in the HBP-A intervention group compared to the ACLT group. In vitro study, apoptosis, hypertrophy, and calcification of rat PMFs after 10% stretch force were significantly improved with HBP-A intervention. Western blot and RT-qPCR showed that hypertrophy, calcification, and p38 MAPK signalling pathway-related markers of PMFs were incredibly depressed in the HBP-A intervention group compared to the 10% stretch force group. In conclusion, HBP-A can slow down meniscus hypertrophy and mineralisation induced by abnormal mechanical loading, and its mechanism of action may be through the p38-MAPK signalling pathway., (© 2024 The Author(s). Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Drought stress impairs plant growth and poses a serious threat to maize (Zea mays) production and yield. Nevertheless, the elucidation of the molecular basis of drought resistance in maize is still uncertain. In this study, we identified ZmSCE1a, a SUMO E2-conjugating enzyme, as a positive regulator of drought tolerance in maize. Molecular and biochemical assays indicated that E3 SUMO ligase ZmMMS21 acts together with ZmSCE1a to SUMOylate histone acetyltransferase complexes (ZmGCN5-ZmADA2b). SUMOylation of ZmGCN5 enhances its stability through the 26S proteasome pathway. Furthermore, ZmGCN5-overexpressing plants showed drought tolerance performance. It alleviated O 2 - accumulation, malondialdehyde content, and ion permeability. What's more, the transcripts of stress-responsive genes and abscisic acid (ABA)-dependent genes were also significantly upregulated in ZmGCN5-overexpressing plants under drought stress. Overexpression of ZmGCN5 enhanced drought-induced ABA production in seedlings. Taken together, our results indicate that ZmSCE1a enhances the stability of ZmGCN5, thereby alleviating drought-induced oxidative damage and enhancing drought stress response in maize., (© 2024 Society for Experimental Biology and John Wiley & Sons Ltd.)

Maize is a valuable raw material for feed and food production. Healthy seed germination is important for improving the yield and quality of maize. Seed aging occurs relatively fast in crops and it is a process that delays germination as well as reduces its rate and even causes total loss of seed viability. However, the physiological and transcriptional mechanisms that regulate maize seeds, especially aging seed germination remain unclear. Coronatine (COR) which is a phytotoxin produced by Pseudomonas syringae and a new type of plant growth regulator can effectively regulate plant growth and development, and regulate seed germination. In this study, the physiological and transcriptomic mechanisms of COR-induced maize seed germination under different aging degrees were analyzed. The results showed that 0.001-0.01 μmol/L COR could promote the germination of aging maize seed and the growth of primary roots and shoots. COR treatment increased the content of gibberellins (GA 3 ) and decreased the content of abscisic acid (ABA) in B73 seeds before germination. The result of RNA-seq analysis showed 497 differentially expressed genes in COR treatment compared with the control. Three genes associated with GA biosynthesis (ZmCPPS2, ZmD3, and ZmGA2ox2), and two genes associated with GA signaling transduction (ZmGID1 and ZmBHLH158) were up-regulated. Three genes negatively regulating GA signaling transduction (ZmGRAS48, ZmGRAS54, and Zm00001d033369) and two genes involved in ABA biosynthesis (ZmVP14 and ZmPCO14472) were down-regulated. The physiological test results also showed that the effects of GA and ABA on seed germination were similar to those of high and low-concentration COR, respectively, which indicated that the effect of COR on seed germination may be carried out through GA and ABA pathways. In addition, GO and KEGG analysis suggested that COR is also highly involved in antioxidant enzyme systems and secondary metabolite synthesis to regulate maize seed germination processes. These findings provide a valuable reference for further research on the mechanisms of maize seed germination., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Increasing planting density is a key strategy for enhancing maize yields 1-3 . An ideotype for dense planting requires a 'smart canopy' with leaf angles at different canopy layers differentially optimized to maximize light interception and photosynthesis 4-6 , among other features. Here we identified leaf angle architecture of smart canopy 1 (lac1), a natural mutant with upright upper leaves, less erect middle leaves and relatively flat lower leaves. lac1 has improved photosynthetic capacity and attenuated responses to shade under dense planting. lac1 encodes a brassinosteroid C-22 hydroxylase that predominantly regulates upper leaf angle. Phytochrome A photoreceptors accumulate in shade and interact with the transcription factor RAVL1 to promote its degradation via the 26S proteasome, thereby inhibiting activation of lac1 by RAVL1 and decreasing brassinosteroid levels. This ultimately decreases upper leaf angle in dense fields. Large-scale field trials demonstrate that lac1 boosts maize yields under high planting densities. To quickly introduce lac1 into breeding germplasm, we transformed a haploid inducer and recovered homozygous lac1 edits from 20 diverse inbred lines. The tested doubled haploids uniformly acquired smart-canopy-like plant architecture. We provide an important target and an accelerated strategy for developing high-density-tolerant cultivars, with lac1 serving as a genetic chassis for further engineering of a smart canopy in maize., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Knee Osteoarthritis (KOA) is a prevalent and debilitating condition affecting millions worldwide, yet its underlying etiology remains poorly understood. Recent advances in neuroimaging and genetic methodologies offer new avenues to explore the potential neuropsychological contributions to KOA. This study aims to investigate the causal relationships between brain-wide morphometric variations and KOA using a genetic epidemiology approach., Method: Leveraging data from 36,778 UK Biobank participants for human brain morphometry and 487,411 UK Biobank participants for KOA, this research employed a two-sample Mendelian Randomization (TSMR) approach to explore the causal effects of 83 brain-wide volumes on KOA. The primary method of analysis was the Inverse Variance Weighted (IVW) and Wald Ratio (WR) method, complemented by MR Egger and IVW methods for heterogeneity and pleiotropy assessments. A significance threshold of p < 0.05 was set to determine causality. The analysis results were assessed for heterogeneity using the MR Egger and IVW methods. Brain-wide volumes with Q&#95;pval < 0.05 were considered indicative of heterogeneity. The MR Egger method was employed to evaluate the pleiotropy of the analysis results, with brain-wide volumes having a p -value < 0.05 considered suggestive of pleiotropy., Results: Our findings revealed significant causal associations between KOA and eight brain-wide volumes: Left parahippocampal volume, Right posterior cingulate volume, Left transverse temporal volume, Left caudal anterior cingulate volume, Right paracentral volume, Left paracentral volume, Right lateral orbitofrontal volume, and Left superior temporal volume. These associations remained robust after tests for heterogeneity and pleiotropy, underscoring their potential role in the pathogenesis of KOA., Conclusion: This study provides novel evidence of the causal relationships between specific brain morphometries and KOA, suggesting that neuroanatomical variations might contribute to the risk and development of KOA. These findings pave the way for further research into the neurobiological mechanisms underlying KOA and may eventually lead to the development of new intervention strategies targeting these neuropsychological pathways., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Liu, Huang, Xiong, Wang, Shen, Zhang, Gao, Wang, Du and Zhan.)

Plant growth exhibits rhythmic characteristics, and gibberellins (GAs) are involved in regulating cell growth, but it is still unclear how GAs crosstalk with circadian rhythm to regulate cell elongation. The study analyzed growth characteristics of wild-type (WT), zmga3ox and zmga3ox with GA 3 seedlings. We integrated metabolomes and transcriptomes to study the interaction between GAs and circadian rhythm in mediating leaf elongation. The rates of leaf growth were higher in WT than zmga3ox , and zmga3ox cell length was shorter when proliferated in darkness than light, and GA 3 restored zmga3ox leaf growth. The differentially expressed genes (DEGs) between WT and zmga3ox were mainly enriched in hormone signaling and cell wall synthesis, while DEGs in zmga3ox were restored to WT by GA 3 . Moreover, the number of circadian DEGs that reached the peak expression in darkness was more than light, and the upregulated circadian DEGs were mainly enriched in cell wall synthesis. The differentially accumulated metabolites (DAMs) were mainly attributed to flavonoids and phenolic acid. Twenty-two DAMs showed rhythmic accumulation, especially enriched in lignin synthesis. The circadian DEGs ZmMYBr41/87 and ZmHB34/70 were identified as regulators of ZmHCT8 and ZmBM1 , which were enzymes in lignin synthesis. Furthermore, GAs regulated ZmMYBr41/87 and ZmHB34/70 to modulate lignin biosynthesis for mediating leaf rhythmic growth.

Excessive nitrogen (N) fertilization in agroecological systems increases nitrous oxide (N 2 O) emissions. 3,4-dimethylpyrazole phosphate (DMPP) is used to mitigate N 2 O losses. The influence of DMPP efficiency on N 2 O mitigation was clearly affected by spatiotemporal heterogeneity. Using field and incubation experiments combined with metagenomic sequencing, we aimed to investigate DMPP efficiency and the underlying microbial mechanisms in dark-brown (Siping, SP), fluvo-aquic (Cangzhou, CZ; Xinxiang, XX), and red soil (Wenzhou, WZ) from diverse climatic zones. In the field experiments, the DMPP efficiency in N 2 O mitigation ranged from 51.6% to 89.9%, in the order of XX, CZ, SP, and WZ. The DMPP efficiency in the incubation experiments ranged from 58.3% to 93.9%, and the order of efficiency from the highest to lowest was the same as that of the field experiments. Soil organic matter, total N, pH, texture, and taxonomic and functional α-diversity were important soil environment and microbial factors for DMPP efficiency. DMPP significantly enriched ammonia-oxidizing archaea (AOA) and nitrite-oxidizing bacteria (NOB), which promoted N-cycling with low N 2 O emissions. Random forest (RF) and regression analyses found that an AOA (Nitrosocosmicus) and NOB (Nitrospina) demonstrated important and positive correlation with DMPP efficiency. Moreover, genes associated with carbohydrate metabolism were important for DMPP efficiency and could influenced N-cycling and DMPP metabolism. The similar DMPP efficiency indicated that the variation in DMPP efficiency was significantly due to soil physicochemical and microbial variations. In conclusion, filling the knowledge gap regarding the response of DMPP efficiency to abiotic and biotic factors could be beneficial in DMPP applications, and in adapting more efficient strategies to improve DMPP efficiency and mitigate N 2 O emissions in multiple regions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

The lengths of the basal internodes is an important factor for lodging resistance of maize (Zea mays). In this study, foliar application of coronatine (COR) to 10 cultivars at the V8 growth stage had different suppression effects on the length of the eighth internode, with three being categorized as strong-inhibition cultivars (SC), five as moderate (MC), and two as weak (WC). RNA-sequencing of the eighth internode of the cultivars revealed a total of 7895 internode elongation-regulating genes, including 777 transcription factors (TFs). Genes related to the hormones cytokinin, gibberellin, auxin, and ethylene in the SC group were significantly down-regulated compared to WC, and more cell-cycle regulatory factors and cell wall-related genes showed significant changes, which severely inhibited internode elongation. In addition, we used EMSAs to explore the direct regulatory relationship between two important TFs, ZmABI7 and ZmMYB117, which regulate the cell cycle and cell wall modification by directly binding to the promoters of their target genes ZmCYC1, ZmCYC3, ZmCYC7, and ZmCPP1. The transcriptome reported in this study will provide a useful resource for studying maize internode development, with potential use for targeted genetic control of internode length to improve the lodging resistance of maize., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Porous graphdiynes are a new class of porous 2D materials with tunable electronic structures and various pore structures. They have potential applications as well-defined nanostructured electrodes and can provide platforms for understanding energy storage mechanisms underlying supercapacitors. Herein, the effect of stacking structure and metallicity on energy storage with such electrodes is investigated. Simulations reveal that supercapacitors based on porous graphdiynes of AB stacking structure can achieve both higher double-layer capacitance and ionic conductivity than AA stacking. This phenomenon is ascribed to more intense image forces in AB stacking, leading to a breakdown of ionic ordering and the formation of effective "free ions". Macroscale analysis shows that doped porous graphdiynes can deliver outstanding gravimetric and volumetric energy and power densities due to their enhanced quantum capacitance. These findings pave the way for designing high-performance supercapacitors by regulating pore topology and metallicity of electrode materials., (© 2023 Wiley-VCH GmbH.)

Straw retention (SR) and organic fertilizer (OF) application contribute to improve soil quality, but it is unclear how the soil microbial assemblage under organic amendments mediate soil biochemical metabolism pathways to perform it. This study collected soil samples from wheat field under different application of fertilizer (chemical fertilizer, as control; SR, and OF) in North China Plain, and systematically investigated the interlinkages among microbe assemblages, metabolites, and physicochemical properties. Results showed that the soil organic carbon (SOC) and permanganate oxidizable organic carbon (LOC) in soil samples followed the trend as OF > SR > control, and the activity of C-acquiring enzymes presented significantly positive correlation with SOC and LOC. In organic amendments, bacteria and fungi community were respectively dominated by deterministic and stochastic processes, while OF exerted more selective pressure on soil microbe. Compared with SR, OF had greater potential to boost the microbial community robustness through increasing the natural connectivity and stimulating fungal taxa activities in inter-kingdom microbial networks. Altogether 67 soil metabolites were significantly affected by organic amendments, most of them belonged to benzenoids (Ben), lipids and lipid-like molecules (LL), and organic acids and derivatives (OA). These metabolites were mainly derived from lipid and amino acid metabolism pathways. A list of keystone genera such as stachybotrys and phytohabitans were identified as important to soil metabolites, SOC, and C-acquiring enzyme activity. Structural equation modeling showed that soil quality properties were closely associated with LL, OA, and PP drove by microbial community assembly and keystone genera. Overall, these findings suggested that straw and organic fertilizer might drive keystone genera dominated by determinism to mediate soil lipid and amino acid metabolism for improving soil quality, which provided new insights into understanding the microbial-mediated biological process in amending soil quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Background: Auxin plays a crucial role in nitrate (NO 3 - )-mediated root architecture, and it is still unclear that if NO 3 - supply modulates auxin reallocation for regulating root formation in maize (Zea mays L.). This study was conducted to investigate the role of auxin efflux carrier ZmPIN1a in the root formation in response to NO 3 - supply., Results: Low NO 3 - (LN) promoted primary root (PR) elongation, while repressed the development of lateral root primordia (LRP) and total root length. LN modulated auxin levels and polar transport and regulated the expression of auxin-responsive and -signaling genes in roots. Moreover, LN up-regulated the expression level of ZmPIN1a, and overexpression of ZmPIN1a enhanced IAA efflux and accumulation in PR tip, while repressed IAA accumulation in LRP initiation zone, which consequently induced LN-mediated PR elongation and LR inhibition. The inhibition rate of PR length, LRP density and number of ZmPIN1a-OE plants was higher than that of wild-type plants after auxin transport inhibitor NPA treatment under NN and LN conditions, and the degree of inhibition of root growth in ZmPIN1a-OE plants was more obvious under LN condition., Conclusion: These findings suggest that ZmPIN1a was involved in modulating auxin levels and transport to alter NO 3 - -mediated root formation in maize., (© 2023. The Author(s).)

Improving crop salt tolerance is an adaptive measure to climate change for meeting future food demands. Previous studies have reported that glycine betaine (GB) plays critical roles as an osmolyte in enhancing plant salt resistance. However, the mechanism underlying the GB regulating plant Na + homeostasis during response to salinity is poorly understood. In this study, hydroponically cultured maize with 125 mM NaCl for inducing salinity stress was treated with 100 μM GB. We found that treatment with GB improved the growth of maize plants under non-stressed (NS) and salinity-stressed (SS) conditions. Treatment with GB significantly maintained the properties of chlorophyll fluorescence, including Fv/Fm, ΦPSII, and ΦNPQ, and increased the activity of the antioxidant enzymes for mitigating salt-induced growth inhibition. Moreover, GB decreased the Na + /K + ratio primarily by reducing the accumulation of Na + in plants. The results of NMT tests further confirmed that GB increased Na + efflux from roots under SS condition, and fluorescence imaging of cellular Na + suggested that GB reduced the cellular allocation of Na + . GB additionally increased Na + efflux in leaf protoplasts under SS condition, and treatment with sodium orthovanadate, a plasma membrane (PM) H + -ATPase inhibitor, significantly alleviated the positive effects of GB on Na + efflux under salt stress. GB significantly improved the vacuolar activity of NHX but had no significant effects on the activity of V type H + -ATPases. In addition, GB significantly upregulated the expression of the PM H + -ATPase genes, ZmMHA2 and ZmMHA4 , and the Na + /H + antiporter gene, ZmNHX1. While, the V type H + -ATPases gene, ZmVP1 , was not significantly regulated by GB. Altogether these results indicate that GB regulates cellular Na + homeostasis by enhancing PM H+-ATPases gene transcription and protein activities to improve maize salt tolerance. This study provided an extended understanding of the functions of GB in plant responses to salinity, which can help the development of supportive measures using GB for obtaining high maize yield in saline conditions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zhu, Li, Zhang, Zhang and Li.)

Background: Low grain water content (GWC) at harvest of maize (Zea mays L.) is essential for mechanical harvesting, transportation and storage. Grain drying rate (GDR) is a key determinant of GWC. Many quantitative trait locus (QTLs) related to GDR and GWC have been reported, however, the confidence interval (CI) of these QTLs are too large and few QTLs has been fine-mapped or even been cloned. Meta-QTL (MQTL) analysis is an effective method to integrate QTLs information in independent populations, which helps to understand the genetic structure of quantitative traits., Results: In this study, MQTL analysis was performed using 282 QTLs from 25 experiments related GDR and GWC. Totally, 11 and 34 MQTLs were found to be associated with GDR and GWC, respectively. The average CI of GDR and GWC MQTLs was 24.44 and 22.13 cM which reduced the 57 and 65% compared to the average QTL interval for initial GDR and GWC QTL, respectively. Finally, 1494 and 5011 candidate genes related to GDR and GWC were identified in MQTL intervals, respectively. Among these genes, there are 48 genes related to hormone metabolism., Conclusions: Our studies combined traditional QTL analyses, genome-wide association study and RNA-seq to analysis major locus for regulating GWC in maize., (© 2022. The Author(s).)

Nitrous oxide (N 2 O) is a pollutant released from agriculture soils following N fertilizer application. N stabilizers, such as N-(n-butyl) thiophosphoric triamide (NBPT) and 3,4-dimethylpyrazole phosphate (DMPP) could mitigate these N 2 O emissions when applied with fertilizer. Here, field experiments were conducted to investigate the microbial mechanisms by which NBPT and DMPP mitigate N 2 O emissions following urea application. We determined dynamic N 2 O emissions and inorganic N concentrations for two wheat seasons and combined this with metagenomic sequencing. Application of NBPT, DMPP, and both NBPT and DMPP together with urea decreased mean N 2 O accumulative emissions by 77.8, 91.4 and 90.7%, respectively, compared with urea application alone, mainly via repressing the increase in NO 2 - concentration after N fertilization. Sequencing results indicated that urea application enriched microorganisms that were positively correlated with N 2 O production, whereas N stabilizers enriched microorganisms that were negatively correlated with N 2 O production. Furthermore, compared to urea application alone, NBPT with urea reduced the abundances of genes related to denitrification, including napA/nasA, nirS/nirK, and norBC, resulting in a higher soil NO 3 - pool. Conversely, DMPP application, either alone or together with NBPT, decreased the abundance of genes involved in ammonia oxidation and denitrification, including amoCAB, hao, napA/nasA, nirS/nirK, and norBC, and maintained a greater soil NH 4 + pool. Both N stabilizers resulted in similar abundances of nirABD-which is related to NO 2 - reducers-as when no N fertilizer was applied, which could prevent NO 2 - accumulation, consequently mitigating N 2 O emissions. These findings suggest that the high effectiveness of N stabilizers on mitigating N 2 O emissions could be attributed to changes to soil microbial communities and N-cycling functional genes to control the by-product or intermediate products of microbial N-cycling processes in agricultural soils., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Background: Lodging is one of the important factors causing maize yield. Plant height is an important factor in determining plant architecture in maize (Zea mays L.), which is closely related to lodging resistance under high planting density. Coronatine (COR), which is a phytotoxin and produced by the pathogen Pseudomonas syringae, is a functional and structural analogue of jasmonic acid (JA)., Results: In this study, we found COR, as a new plant growth regulator, could effectively reduce plant height and ear height of both hybrids (ZD958 and XY335) and inbred (B73) maize by inhibiting internode growth during elongation, thus improve maize lodging resistance. To study gene expression changes in internode after COR treatment, we collected spatio-temporal transcriptome of inbred B73 internode under normal condition and COR treatment, including the three different regions of internode (fixed, meristem and elongation regions) at three different developmental stages. The gene expression levels of the three regions at normal condition were described and then compared with that upon COR treatment. In total, 8605 COR-responsive genes (COR-RGs) were found, consist of 802 genes specifically expressed in internode. For these COR-RGs, 614, 870, 2123 of which showed expression changes in only fixed, meristem and elongation region, respectively. Both the number and function were significantly changed for COR-RGs identified in different regions, indicating genes with different functions were regulated at the three regions. Besides, we found more than 80% genes of gibberellin and jasmonic acid were changed under COR treatment., Conclusions: These data provide a gene expression profiling in different regions of internode development and molecular mechanism of COR affecting internode elongation. A putative schematic of the internode response to COR treatment is proposed which shows the basic process of COR affecting internode elongation. This research provides a useful resource for studying maize internode development and improves our understanding of the COR regulation mechanism based on plant height.

Rice (Oryza sativa) is the staple food for over half the world's population. Drought stress imposes major constraints on rice yields. Intriguingly, labdane-related diterpenoid (LRD) phytoalexins in maize (Zea mays) affect drought tolerance, as indicated by the increased susceptibility of an insertion mutant of the class II diterpene cyclase ZmCPS2/An2 that initiates such biosynthesis. Rice also produces LRD phytoalexins, utilizing OsCPS2 and OsCPS4 to initiate a complex metabolic network. For genetic studies of rice LRD biosynthesis the fast-growing Kitaake cultivar was selected for targeted mutagenesis via CRISPR/Cas9, with an initial focus on OsCPS2 and OsCPS4. The resulting cps2 and cps4 knockout lines were further crossed to create a cps2x4 double mutant. Both CPSs also were overexpressed. Strikingly, all of the cv Kitaake cps mutants exhibit significantly increased susceptibility to drought, which was associated with reduced stomatal closure that was evident even under well-watered conditions. However, CPS overexpression did not increase drought resistance, and cps mutants in other cultivars did not alter susceptibility to drought, although these also exhibited lesser effects on LRD production. The results suggest that LRDs may act as a regulatory switch that triggers stomatal closure in rice, which might reflect the role of these openings in microbial entry., (© 2021 The Authors. New Phytologist © 2021 New Phytologist Foundation.)

Background: Neck pain is a common clinical disease, which seriously affects people's mental health and quality of life and results in loss of social productivity. Improving neck pain's curative effect and reducing its recurrence rate are major medical problems. Shi's manipulation therapy has unique advantages and technical features that aid in the diagnosis and treatment of neck pain. Compared with first-line non-steroidal anti-inflammatory drug (NSAID) treatment of neck pain, Shi's cervical manipulation lacks the relevant research basis of therapeutic advantage, safety, and satisfaction for treating acute and subacute neck pain. Herein, we aim to confirm our hypothesis in a clinical trial that the safety and efficacy of Shi's cervical manipulation will be more effective, safer, and more satisfactory than NSAIDs to treat acute and subacute neck pain., Methods: In this multicenter, positive-controlled, randomized clinical trial, traditional analgesic drug (NSAID) is used to evaluate and show that Shi's manipulation is more effective, safe, and satisfactory for treating acute and subacute neck pain. Overall, 240 subjects are randomly divided into the trial and control groups, with both groups treated by the corresponding main intervention method for up to 12 weeks. Clinical data will be collected before the intervention and immediately after the first treatment; at 3 days and 1, 2, 4, 8, and 12 weeks after the intervention; and at 26 and 52 weeks after treatment follow-up of clinical observation index data collection. The clinical observation indices are as follows: (1) cervical pain is the primary observation index, measured by Numerical Rating Scale. The secondary indices include the following: (2) cervical dysfunction index, measured by patient self-evaluation using cervical Neck Disability Index; (3) cervical activity measurement, measured by the cervical vertebra mobility measurement program of Android mobile phone system; (4) overall improvement, measured by patient self-evaluation with SF-36; and (5) satisfactory treatment, determined by patient self-evaluation., Discussion: We will discuss whether Shi's cervical manipulation has greater advantages in efficacy, safety, and satisfaction of acute and subacute neck pain than traditional NSAIDs, to provide a scientific basis for the dissemination and application of Shi's cervical manipulation., Trial Registration: China Registered Clinical Trial Registration Center ChiCTR1900021371 . Registered on 17 February 2019.

Dodder is a holoparasitic flowering plant that re-establishes parasitism with the host when broken off from the host. However, how in vitro dodder shoots recycle stored nutrients to maintain growth for reparasitizing hosts is not well characterized. Here, the spatial and temporal distribution characteristics of carbohydrates and reactive oxygen species (ROS) were analysed to explore the mechanism of recycling stored nutrients in dodder shoots in vitro. Our results showed that in vitro dodder shoots grew actively for more than 10 d, while dry mass decreased continuously. During this process, the transcript levels and activities of amylases gradually increased until 2 d and then declined in basal stems, which induced starch degradation at the tissue, cellular and subcellular levels. Additionally, the distribution characteristics of H 2 O 2 and the activities and transcript levels of antioxidant enzymes indicated that shoot tips exhibited more robust ROS-scavenging capacity, and basal stems maintained higher ROS accumulation. Comparative proteomics analysis revealed that starch in basal stems acted as an energy source, and the glycolysis, TCA cycle and pentose phosphate pathway represented the energy supply for shoot tip elongation with time. These results indicated that efficient nutrient recycling and ROS modulation facilitated the parasitism of dodder grown in vitro by promoting shoot elongation growth to reach the host., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Salinity stress impairs plant growth and causes crops to yield losses worldwide. Reduction of in vivo gibberellin acid (GA) level is known to repress plant size but is beneficial to plant salt tolerance. However, the mechanisms of in vivo GA deficiency-enhanced salt tolerance in maize are still ambiguous. In this study, we generated two independent maize knockout mutant lines of ent -copalyl diphosphate synthase (one of the key enzymes for early steps of GA biosynthesis), zmcps-1 and zmcps-7 , to explore the role of GA in maize salt tolerance. The typical dwarf phenotype with lower GA content and delayed leaf senescence under salinity was observed in the mutant plants. The leaf water potential and cell turgor potential were significantly higher in zmcps-1 and zmcps-7 than in the wild type (WT) under salt stress. The mutant plants exhibited a lower superoxide anion production rate in leaves and also a downregulated relative expression level of NAPDH oxidase ZmRbohA-C than the WT maize under salt stress. Also, the mutant plants had higher enzymatic activities of superoxide dismutase (SOD) and catalase (CAT) and higher content of soluble sugars and proline under salt stress. The Na + /K + ratio was not significantly different between the mutant maize plants and WT plants under salt stress conditions, but the Na + and K + content was increased in zmcps-1 and zmcps-7 leaves and shoots. Na + fluorescent dye staining showed that the mutant leaves have significantly higher vacuolar Na + intensity than the WT maize. The expression level of vacuolar Na + /H + exchanger gene ZmNHX1 and vacuolar proton pump genes ZmVP1-1 and ZmVP2 were upregulated in the zmcps-1 and zmcps-7 plants under salinity, further proving that in vivo GA deficiency enhanced vacuolar Na + sequestration in zmcps-1 and zmcps-7 leaves cells to avoid Na + cytotoxicity. Together, our results suggested that maintaining ROS homeostasis and enhancing vacuolar Na + sequestration could be involved in GA deficiency-improved maize salt tolerance., (Copyright © 2020 Zhang, Wang, Xing, Wan, Wang, Zhang, Wang, Li and Zhang.)

Use of growth retardants enables post-planting optimization of vegetative growth, which is particularly important given ongoing climate change. Mepiquat chloride is an economical and safe retardant widely applied in cotton farming, but it is not uniformly effective. Here, identification of its molecular target as the ent-copalyl diphosphate synthase that initiates gibberellin biosynthesis enabled the introduction of selective agrochemical inhibition, leaving intact more specialized metabolism important for resistance to biotic and abiotic stresses.

Ethephon efficiently regulates plant growth to modulate the maize (Zea mays L.) stalk strength and yield potential, yet there is little information on how ethylene governs a specific cellular response for altering internode elongation. Here, the internode elongation kinetics, cell morphological and physiological properties and transcript expression patterns were investigated in the ethephon-treated elongating internode. Ethephon decreased the internode elongation rate, shortened the effective elongation duration, and advanced the growth process. Ethephon regulated the expression patterns of expansin and secondary cell wall-associated cellulose synthase genes to alter cell size. Moreover, ethephon increased the activities and transcripts level of phenylalanine ammonia-lyase and peroxidase, which contributed to lignin accumulation. Otherwise, ethephon-boosted ethylene evolution activated ethylene signal and increased ZmGA2ox3 and ZmGA2ox10 transcript levels while down-regulating ZmPIN1a, ZmPIN4 and ZmGA3ox1 transcript levels, which led to lower accumulation of gibberellins and auxin. In addition, transcriptome profiles confirmed previous results and identified several transcription factors that are involved in the ethephon-modulated transcriptional regulation of cell wall biosynthesis and modification and responses to ethylene, gibberellins and auxin. These results indicated that ethylene-modulated auxin and gibberellins signaling mediated the transcriptional operation of cell wall modification to regulate cell elongation in the ethephon-treated maize internode., (Copyright © 2019 Elsevier B.V. All rights reserved.)

APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) family transcription factors have well-documented functions in stress responses, but their roles in brassinosteroid (BR)-regulated growth and stress responses have not been established. Here, we show that the Arabidopsis ( Arabidopsis thaliana ) stress-inducible AP2/ERF transcription factor TINY inhibits BR-regulated growth while promoting drought responses. TINY -overexpressing plants have stunted growth, increased sensitivity to BR biosynthesis inhibitors, and compromised BR-responsive gene expression. By contrast, tiny tiny2 tiny3 triple mutants have increased BR-regulated growth and BR-responsive gene expression. TINY positively regulates drought responses by activating drought-responsive genes and promoting abscisic acid-mediated stomatal closure. Global gene expression studies revealed that TINY and BRs have opposite effects on plant growth and stress response genes. TINY interacts with and antagonizes BRASSINOSTERIOID INSENSITIVE1-ETHYL METHANESULFONATE SUPRESSOR1 (BES1) in the regulation of these genes. Glycogen synthase kinase 3-like protein kinase BR-INSENSITIVE2 (BIN2), a negative regulator in the BR pathway, phosphorylates and stabilizes TINY, providing a mechanism for BR-mediated downregulation of TINY to prevent activation of stress responses under optimal growth conditions. Taken together, our results demonstrate that BR signaling negatively regulates TINY through BIN2 phosphorylation and TINY positively regulates drought responses, as well as inhibiting BR-mediated growth through TINY-BES1 antagonistic interactions. Our results thus provide insight into the coordination of BR-regulated growth and drought responses., (© 2019 American Society of Plant Biologists. All rights reserved.)

The Ag NPs@HKUST-1 composites have been successfully prepared with different loading amounts of silver nanoparticles in HKUST-1 featuring a three-dimensional system of channels constructed by benzene-1,3,5-tricarboxylate and dimeric cupric units by a simple one-pot hydrothermal method, and characterized by various microscopy and spectroscopy analysis techniques. The average particle size of Ag NPs increased with the increase of the loading amount of Ag NPs. The experimental results showed that the degradation of sulfur mustard (HD) under ambient conditions followed pseudo-first order reaction kinetics. Additionally, the optimized Ag NPs@HKUST-1 (wherein Ag is l6.67 wt%) exhibited the highest degradation efficacy with an equilibrium rate constant and half-life for HD of 0.0450 min -1 and 15.34 min, respectively. These values were significantly higher than those for pure HKUST-1 with an equilibrium rate constant and half-life for HD of 0.0168 min -1 and 41.29 min, under the same experimental conditions. Gas chromatography-mass spectrometry (GC-MS) analysis on the product of 2-chloroethylethyl sulfide (2-CEES) degraded by Ag NPs@HKUST-1 showed that 2-hydroxyethyl ethyl sulfide (2-HEES) is the sole product, indicating that the remarkable enhancement of the degradation of HD must be due to the Ag NPs, which can promote hydrolysis of the chemical war agent in the composite., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Coronatine (COR) is a phytotoxin produced by Pseudomonas syringae. Its structure is similar to those of jasmonates (JAs), which play diverse roles in multiple plant biotic and abiotic defenses. However, the biological activity of COR is 1000 times greater than the activity of JA. In addition to being involved in the JA pathway, COR affects plant photosynthetic efficiency. In this study, we examined wheat blade pretreatment with COR. Blades treated with COR remained green longer than those of control plants under drought stress conditions, resulting in less yield loss with COR treatment. To investigate the mechanism of COR in drought resistance further, we employed two-dimensional gel electrophoresis technology and matrix-assisted laser desorption/ionization mass spectrometry to sequester and identify key proteins. Six COR-inducible proteins that are located in the chloroplast and involved directly in photosynthesis were found. The wheat homologue of protein gi|326509937 is degradation of periplasmic proteins 1 (DEGP1) in Arabidopsis, which is a response to photosystem II reparation, and was maintained at a low level with COR treatment. Finally, we measured levels of chlorophyll and photosynthetic performance to reveal the phenotypic effect of COR. Taken together, the results demonstrate that COR enhances drought tolerance by maintaining high photosynthetic performance., (Copyright © 2018 Elsevier GmbH. All rights reserved.)

Currently extensive effort is compulsively expended to decontaminate efficiently banned chemical war agents. In this work, H5PV2Mo10O40 molecules have been encapsulated in mesoporous MIL-101(Cr), which features two types of mesoporous cages (internal diameters of 29 Å and 34 Å) and microporous windows (diameters of 12 Å and 16 Å), leading to the formation of a new composite H5PV2Mo10O40@MIL-101(Cr) through a simple impregnation method. The composite was characterized thoroughly by elemental analysis, FT-IR spectroscopy, powder X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, TG/DTA, and textural analysis thereby confirming the encapsulation of the H5PV2Mo10O40 into MIL-101(Cr). The decontamination efficiency of sulfur mustard (4 μL HD in 40 μL of petroleum ether) by 20 mg of the composite is found to be 97.39% in 120 min under ambient conditions. GC-MS analysis on the decontaminated products using 2-chloroethyl ethyl sulfide (CEES), which has been widely used as a simulant of sulfur mustard, showed that MIL-101(Cr) just decontaminates CEES by adsorption, while CEES can be decontaminated under ambient conditions by a synergetic combination of adsorption of MIL-101(Cr) and subsequent chemical oxidation degradation to nontoxic 2-chloroethyl ethyl sulfoxide (CEESO) due to the presence of highly dispersed H5PV2Mo10O40 within the composites.

Cuticular wax is the outermost thin hydrophobic layer covering the surface of aerial plant parts, which provides a primary waterproof barrier and protection against different environmental stresses. The aim of the present study was to investigate the role of ethephon, as an ethylene-releasing compound, in counteracting drought stress by modulating cuticular wax biosynthesis, water balance, and antioxidant regulation in maize seedlings. Our results showed that ethephon significantly increased the ethylene evolution rate, regulate the expression of cuticular wax synthesis regulatory gene ZmERE and the wax biosynthetic genes ZmGL1, ZmGL15, ZmFDH1, and ZmFAE1, and promote cuticular wax accumulation in maize seedlings under normal or drought stress conditions. Moreover, ethephon was shown to might markedly reduce water loss and chlorophyll leaching in leaves, and maintain higher relative water content and leaf water potential under drought stress. Ethephon significantly decreased malondialdehyde and hydrogen peroxide concentrations and electrolyte leakage, but increased the accumulation of proline and the activities of SOD, POD, and CAT. In addition, ethephon resulted in an increase in the ratio of root and shoot under drought stress. These results indicated that ethephon could improve maize performance under drought stress by modulating cuticular wax synthesis to maintain water status and membrane stability for plant growth., (Copyright © 2017 Elsevier GmbH. All rights reserved.)

Plant steroid hormones, brassinosteroids (BRs), play important roles in growth and development. BR signaling controls the activities of BRASSINOSTERIOD INSENSITIVE1-EMS-SUPPRESSOR1/BRASSINAZOLE-RESISTANT1 (BES1/BZR1) family transcription factors. Besides the role in promoting growth, BRs are also implicated in plant responses to drought stress. However, the molecular mechanisms by which BRs regulate drought response have just begun to be revealed. The functions of WRKY transcription factors in BR-regulated plant growth have not been established, although their roles in stress responses are well documented. Here, we found that three Arabidopsis thaliana group III WRKY transcription factors, WRKY46, WRKY54, and WRKY70, are involved in both BR-regulated plant growth and drought response as the wrky46 wrky54 wrky70 triple mutant has defects in BR-regulated growth and is more tolerant to drought stress. RNA-sequencing analysis revealed global roles of WRKY46, WRKY54, and WRKY70 in promoting BR-mediated gene expression and inhibiting drought responsive genes. WRKY54 directly interacts with BES1 to cooperatively regulate the expression of target genes. In addition, WRKY54 is phosphorylated and destabilized by GSK3-like kinase BR-INSENSITIVE2, a negative regulator in the BR pathway. Our results therefore establish WRKY46/54/70 as important signaling components that are positively involved in BR-regulated growth and negatively involved in drought responses., (© 2017 American Society of Plant Biologists. All rights reserved.)

The DNA is particularly sensitive to UV-B radiation and can readily be damaged by UV-B stress, resulting to the formation of photoproducts like cyclobutane pyrimidine dimers (CPDs). Silicon has multifarious benefits to plants, especially under biotic and abiotic stress. In this study, we used soybean seedlings to determine whether silicon could alleviate damage to DNA caused by UV-B stress. Silicon significantly reduced the accumulation of CPDs, lessening the damage of UV-B stress to the seedlings by the following three mechanisms: (1) increasing the concentration of UV-B absorbing compounds to reduce damage; (2) strengthening the antioxidant capacity of plants represented by higher levels of non-enzymatic antioxidants and (3) increasing the photolyase gene expression, thus accelerating photorepair., (Copyright © 2016 Elsevier GmbH. All rights reserved.)

Abscisic acid (ABA) is a vital cellular signal in plants, and effective ABA signalling is pivotal for stress tolerance. AtLOS5 encoding molybdenum cofactor sulphurase is a key regulator of ABA biosynthesis. Here, transgenic AtLOS5 plants were generated to explore the role of AtLOS5 in salt tolerance in maize. AtLOS5 overexpression significantly up-regulated the expression of ZmVp14-2, ZmAO, and ZmMOCO, and increased aldehyde oxidase activities, which enhanced ABA accumulation in transgenic plants under salt stress. Concurrently, AtLOS5 overexpression induced the expression of ZmNHX1, ZmCBL4, and ZmCIPK16, and enhanced the root net Na(+) efflux and H(+) influx, but decreased net K(+) efflux, which maintained a high cytosolic K(+)/Na(+) ratio in transgenic plants under salt stress. However, amiloride or sodium orthovanadate could significantly elevate K(+) effluxes and decrease Na(+) efflux and H(+) influx in salt-treated transgenic roots, but the K(+) effluxes were inhibited by TEA, suggesting that ion fluxes regulated by AtLOS5 overexpression were possibly due to activation of Na(+)/H(+) antiport and K(+) channels across the plasma membrane. Moreover, AtLOS5 overexpression could up-regulate the transcripts of ZmPIP1:1, ZmPIP1:5, and ZmPIP2:4, and enhance root hydraulic conductivity. Thus transgenic plants had higher leaf water potential and turgor, which was correlated with greater biomass accumulation under salt stress. Thus AtLOS5 overexpression induced the expression of ABA biosynthetic genes to promote ABA accumulation, which activated ion transporter and PIP aquaporin gene expression to regulate root ion fluxes and water uptake, thus maintaining high cytosolic K(+) and Na(+) homeostasis and better water status in maize exposed to salt stress., (© The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.)

While the developmental role of the SOX9 transcription factor in chondrocyte differentiation and cartilage formation is well documented, age-dependent SOX9 expression in articular chondrocytes (ACs) and its regulatory mechanisms remain unclear. This study aimed to explore epigenetic regulatory mechanisms for age-related changes in SOX9 expression in ACs of mice, spanning from the developmental stage to 18 months of age. Sox9 mRNA and protein were highly expressed in ACs during joint development but significantly decreased after 2 months of age. Histopathological features of osteoarthritis were not observed in examined hip and shoulder joints by 18 months of age. Epigenetic studies revealed that DNA methylation levels were increased at specific CpG islands of the Sox9 gene at 6 and 12 months; treatment of cultured ACs from 6-month-old mice with 5-azacytidine (an inhibitor of DNA methylation) elevated the level of Sox9 expression in ACs by lowering DNA methylation levels in the Sox9 promoter region. Histone 3 lysine 4 dimethylation (H3K4me2, a histone modification for transcriptional activation) in the Sox9 promoter region was decreased with age, which was associated with the age-dependent decrease in SOX9 expression in ACs. Knockdown of lysine-specific demethylase-1 up-regulated SOX9 expression in ACs of adult mice through increased recruitment of H3K4me2 in the Sox9 promoter region. Our results suggest that SOX9 expression in mouse ACs is significantly decreased after the completion of joint development. These age-dependent changes in SOX9 expression are dynamically regulated by DNA methylation and histone methylation., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The development of disease-modifying pharmacologic therapy for osteoarthritis currently faces major obstacles largely because the pathogenetic mechanisms for the development of osteoarthritis remain unclear. Previous studies suggest that the alterations in expression of catabolic and anabolic genes in articular chondrocytes may be involved in the pathogenesis of osteoarthritis. However, the regulatory mechanisms for gene expression in osteoarthritic chondrocytes are largely unknown. The objective of this review is to highlight the recent studies on epigenetic regulation of gene expression in the development of osteoarthritis. The review will begin with current understanding of epigenetic mechanisms, especially the newly emerging areas including the regulatory role of non-coding RNAs in gene expression and crosstalk among the epigenetic mechanisms. The main content of this review focuses on the significance of epigenetic regulation of the expression of catabolic and anabolic genes in osteoarthritic chondrocytes, including the regulatory roles of various epigenetic mechanisms in the expression of genes for specific matrix-degrading proteinases, cytokines, and extracellular matrix proteins. Recent novel findings on the epigenetic regulation of specific transcription factor genes are particularly important for the understanding of osteoarthritis pathogenesis, as these transcription factors may act as upstream regulators of multiple catabolic and anabolic genes. In conclusion, these recent advances in epigenetic studies have shed light on the importance of epigenetic regulation of gene expression in the development of osteoarthritis, leading to a better understanding of the epigenetic mechanisms underlying the pathogenesis of osteoarthritis. This may promote the development of new epigenetics-based strategies for the treatment of osteoarthritis. This article is part of a Directed Issue entitled: Epigenetics dynamics in development and disease., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Osteoarthritis (OA) is the most common form of joint disease and the leading cause of chronic disability in middle-aged and older populations. The development of disease-modifying therapy for OA currently faces major obstacles largely because the regulatory mechanisms for the function of joint tissue cells remain unclear. Previous studies have found that the alterations in gene expression of specific transcription factors (TFs), pro- or anti-inflammatory cytokines, matrix proteinases and extracellular matrix (ECM) proteins in articular cartilage may be involved in the development of OA. However, the regulatory mechanisms for the expression of those genes in OA chondrocytes are largely unknown. The recent advances in epigenetic studies have shed lights on the importance of epigenetic regulation of gene expression in the development of OA. In this review, we summarize and discuss the recent studies on the regulatory roles of various epigenetic mechanisms in the expression of genes for specific TFs, cytokines, ECM proteins and matrix proteinases, as well the significance of these epigenetic mechanisms in the pathogenesis of OA.