Inter-relationships of galectin-3 and NLR family pyrin domain containing 3 inflammasomes with oral lichen planus: a preliminary cross-sectional in vitro study.

BACKGROUND: The nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome has been reported to be highly expressed in oral lesions with the potential for malignant development such as oral lichen planus (OLP). And the NLRP3 inflammasome can be activated by galectin-3 (Gal-3) in immune-mediated chronic inflammatory diseases. This study aimed to explore the inter-relationships among Gal-3, NLRP3 inflammasome, and OLP. METHODS: A cross-sectional analysis of oral biopsy specimens from 30 patients with Erosive OLP and 30 healthy controls was performed. Immunohistochemical staining was used to evaluate the expression of Gal-3 and NLRP3 inflammasome. Two-sample t-test and Pearson correlation test were applied to analyze the data. RESULTS: Erosive OLP patients had significantly higher Gal-3 levels compared with controls (p < 0.0001). A similar pattern emerged for NLRP3 inflammasome. In the overall sample, a positive correlation was observed between Gal-3 and NLRP3 (r = 0.92, p < 0.01). CONCLUSIONS: Patients with Erosive OLP lesions showed increased protein expression levels of Gal-3. A positive correlation was observed between Gal-3 and NLRP3 inflammasome.

Transcriptome Analysis Reveals the Potential Molecular Mechanisms of Tiller Bud Development in Orchardgrass.

Tillering is a special type of branching and one of the important contributors to the yield of cereal crops. Strigolactone and sucrose play a vital role in controlling tiller formation, but their mechanism has not been elucidated completely in most crops. Orchardgrass (Dactylis glomerata L.) is an important perennial forage with prominent tillering ability among crops. To date, the mechanism of tillering in orchardgrass is still largely unknown. Therefore, we performed a transcriptome and miRNA analysis to reveal the potential RNA mechanism of tiller formation under strigolactone and sucrose treatment in orchardgrass. Our results found that D3, COL5, NCED1, HXK7, miRNA4393-z, and miRNA531-z could be key factors to control tiller bud development in orchardgrass. In addition, strigolactones might affect the ABA biosynthesis pathway to regulate the tiller bud development of orchardgrass, which may be related to the expression changes in miRNA4393-z, NCED1, and D10. miRNA531-z could be involved in the interaction of strigolactones and sucrose in regulating tillering. These results will be further used to clarify the potential mechanism of tillering for breeding new high-tillering and high-production orchardgrass varieties and beneficial to improving the production and reproduction of crops.

Genome-Wide Characterization of the Aux/IAA Gene Family in Orchardgrass and a Functional Analysis of DgIAA21 in Responding to Drought Stress.

Drought stress is an important factor that reduces plant biomass production and quality. As one of the most important economic forage grasses, orchardgrass (Dactylis glomerata) has high drought tolerance. Auxin/indole-3-acetic acid (Aux/IAA) is one of the early responsive gene families of auxin and plays a key role in the response to drought stress. However, the characteristics of the Aux/IAA gene family in orchardgrass and their potential function in responding to drought stress remain unclear. Here, 30 Aux/IAA members were identified in orchardgrass. Segmental duplication may be an important driving force in the evolution of the Aux/IAA gene family in orchardgrass. Some Aux/IAA genes were induced by IAA, drought, salt, and temperature stresses, implying that these genes may play important roles in responding to abiotic stresses. Heterologous expression in yeast revealed that DgIAA21 can reduce drought tolerance. Similarly, the overexpression of DgIAA21 also reduced drought tolerance in transgenic Arabidopsis, which was supported by lower total chlorophyll content and relative water content as well as higher relative electrolyte leakage and malondialdehyde content (MDA) than Col-0 plants under drought conditions. The results of this study provided valuable insight into the function of DgIAAs in response to drought stress, which can be further used to improve forage grass breeding programs.

Transcriptome Profiling Provides Insights into the Early Development of Tiller Buds in High- and Low-Tillering Orchardgrass Genotypes.

Orchardgrass (Dactylis glomerata L.) is among the most economically important perennial cool-season grasses, and is considered an excellent hay, pasture, and silage crop in temperate regions worldwide. Tillering is a vital feature that dominates orchardgrass regeneration and biomass yield. However, transcriptional dynamics underlying early-stage bud development in high- and low-tillering orchardgrass genotypes are unclear. Thus, this study assessed the photosynthetic parameters, the partially essential intermediate biomolecular substances, and the transcriptome to elaborate the early-stage profiles of tiller development. Photosynthetic efficiency and morphological development significantly differed between high- (AKZ-NRGR667) and low-tillering genotypes (D20170203) at the early stage after tiller formation. The 206.41 Gb of high-quality reads revealed stage-specific differentially expressed genes (DEGs), demonstrating that signal transduction and energy-related metabolism pathways, especially photosynthetic-related processes, influence tiller induction and development. Moreover, weighted correlation network analysis (WGCNA) and functional enrichment identified distinctively co-expressed gene clusters and four main regulatory pathways, including chlorophyll, lutein, nitrogen, and gibberellic acid (GA) metabolism pathways. Therefore, photosynthesis, carbohydrate synthesis, nitrogen efficient utilization, and phytohormone signaling pathways are closely and intrinsically linked at the transcriptional level. These findings enhance our understanding of tillering in orchardgrass and perennial grasses, providing a new breeding strategy for improving forage biomass yield.

Analytical solutions for time-dependent kinematic three-dimensional magnetic reconnection.

Magnetic reconnection is a process that can rapidly convert magnetic field energy into plasma thermal energy and kinetic energy, and it is also an important energy conversion mechanism in space physics, astrophysics and plasma physics. Research related to analytical solutions for time-dependent three-dimensional magnetic reconnection is extremely difficult. For decades, several mathematical descriptions have been developed regarding different reconnection mechanisms, in which the equations based on magnetohydrodynamics theory outside the reconnection diffusion region are widely accepted. However, the equation set cannot be analytically solved unless specified constraints are imposed or the equations are reduced. Based on previous analytical methods for kinematic stationary reconnection, here the analytical solutions for time-dependent kinematic three-dimensional magnetic reconnection are discussed. In contrast to the counter-rotating plasma flows that existed in steady-state reconnection, it is found that spiral plasma flows, which have never been reported before, can be generated if the magnetic field changes exponentially with time. These analyses reveal new scenarios for time-dependent kinematic three-dimensional magnetic reconnection, and the deduced analytical solutions could improve our understanding of the dynamics involved in reconnection processes, as well as the interactions between the magnetic field and plasma flows during magnetic reconnection.

Genome-Wide Identification, Characterization, and Expression of TCP Genes Family in Orchardgrass.

Plant-specific TCP transcription factors regulate several plant growth and development processes. Nevertheless, little information is available about the TCP family in orchardgrass (Dactylis glomerata L.). This study identified 22 DgTCP transcription factors in orchardgrass and determined their structure, phylogeny, and expression in different tissues and developmental stages. The phylogenetic tree classified the DgTCP gene family into two main subfamilies, including class I and II supported by the exon-intron structure and conserved motifs. The DgTCP promoter regions contained various cis-elements associated with hormones, growth and development, and stress responses, including MBS (drought inducibility), circadian (circadian rhythms), and TCA-element (salicylic acid responsiveness). Moreover, DgTCP9 possibly regulates tillering and flowering time. Additionally, several stress treatments upregulated DgTCP1, DgTCP2, DgTCP6, DgTCP12, and DgTCP17, indicting their potential effects regarding regulating responses to the respective stress. This research offers a valuable basis for further studies of the TCP gene family in other Gramineae and reveals new ideas for increasing gene utilization.

Protein kinase C beta relieves autism-like behavior in EN2 knockout mice via upregulation of the FTO/PGC-1α/UCP1 axis.

Increasing evidence suggests that disruption of neuron activity contributes to the autistic phenotype. Thus, we aimed in this study to explore the role of protein kinase C beta (PKCß) in the regulation of neuron activity in an autism model. The expression of PKCß in the microarray data of autism animal models was obtained from the Gene Expression Omnibus database. Then, mice with autism-like behavior were prepared in EN2 knockout (-/- ) mice. The interaction between PKCß on fat mass and obesity-associated protein (FTO) as well as between PGC-1α and uncoupling protein 1 (UCP1) were characterized. The effect of FTO on the N6 -methyladenosine (m6A) modification level of proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) was assayed. Following transfection of overexpressed PKCß and/or silenced UCP1, effects of PKCß and UCP1 in autism-like behaviors in EN2-/- mice were analyzed. Results showed that PKCß was downregulated in EN2-/- mouse brain tissues or neurons. PKCß promoted the expression and stability of FTO, which downregulated the m6A modification level of PGC-1α to promote its expression. Moreover, PGC-1α positively targeted the expression of UCP1. PKCß knockdown enhanced sociability and spatial exploration ability, and reduced neuron apoptosis in EN2-/- mouse models of autism, which was reversed by UCP1 overexpression. Collectively, PKCß overexpression leads to activation of the FTO/m6A/PGC-1α/UCP1 axis, thus inhibiting neuron apoptosis and providing neuroprotection in mice with autism-like behavior.

Genome-wide identification of MADS-box gene family in orchardgrass and the positive role of DgMADS114 and DgMADS115 under different abiotic stress.

Abiotic stress, a major factor limit growth and productivity of major crops. Orchardgrass is one of the most important cool-season forage grasses in the world, and it is highly tolerant to abiotic stress. The MADS-box transcription factor family is one of the largest families in plants, and it plays vital roles in multiple biological processes. However, MADS-box transcription factors in orchardgrass, especially those involved in abiotic stress, have not yet been elucidated. Here, 123 DgMADS-box members were identified in orchardgrass and a detailed overview has been presented. Syntenic analysis indicated that the expansion of the DgMADS-box genes in orchardgrass is mainly dependent on tandem duplication events. Some DgMADS-box genes were induced by multiple abiotic stresses, indicating that these genes may play critical regulatory roles in orchardgrass response to various abiotic stresses. Heterologous expression showed that DgMADS114 and DgMADS115 could enhance stress tolerance of transgenic Arabidopsis, as revealed by longer root length or higher survival rates under PEG, NaCl, ABA, and heat stress. The results of this study provide a scientific basis for clarifying the functional characterization of MADS-box genes in orchardgrass in response to environmental stress can be further used to improve forages and crops via breeding programs.

Targeting APLN/APJ restores blood-testis barrier and improves spermatogenesis in murine and human diabetic models.

Type 2 diabetes mellitus is one of the most prevalent metabolic diseases presenting with systemic pathologies, including reproductive disorders in male diabetic patients. However, the molecular mechanisms that contributing to spermatogenesis dysfunction in diabetic patients have not yet been fully elucidated. Here, we perform STRT-seq to examine the transcriptome of diabetic patients' testes at single-cell resolution including all major cell types of the testis. Intriguingly, whereas spermatogenesis appears largely preserved, the gene expression profiles of Sertoli cells and the blood-testis barrier (BTB) structure are dramatically impaired. Among these deregulate pathways, the Apelin (APLN) peptide/Apelin-receptor (APJ) axis is hyper-activated in diabetic patients' testes. Mechanistically, APLN is produced locally by Sertoli cells upon high glucose treatment, which subsequently suppress the production of carnitine and repress the expression of cell adhesion genes in Sertoli cells. Together, these effects culminate in BTB structural dysfunction. Finally, using the small molecule APLN receptor antagonist, ML221, we show that blocking APLN/APJ significantly ameliorate the BTB damage and, importantly, improve functional spermatogenesis in diabetic db/db mice. We also translate and validate these findings in cultured human testes. Our findings identify the APLN/APJ axis as a promising therapeutic target to improve reproduction capacity in male diabetic patients.

Diagnostic value of oral "beefy red" patch combined with fingertip blood mean corpuscular volume in vitamin B12 deficiency.

OBJECTIVES: To investigate the diagnostic value of accessible fingertip mean corpuscular volume (MCV) combined with a visible "beefy red" patch in the diagnosis of vitamin B12 (VB12) deficiency in local clinics and hospitals without in-house clinical laboratories, especially in remote areas. MATERIALS AND METHODS: The medical history data of patients complaining of oral mucosal pain at the Stomatological Hospital of Southern Medical University were reviewed. All included patients underwent fingertip blood routine examination, specific serological test (serum VB12, folic acid, iron, and ferritin), and detailed oral clinical examinations. According to the results of the serum VB12 test patients were divided into case and control groups. In diagnostic test, the diagnostic value of the "beefy red" patch and elevated MCV in VB12 deficiency was evaluated by the receiver operator characteristic curve. RESULTS: There were more female patients than male patients in the case group (serum VB12 level < 148 pmol/L, n = 81) and control group (serum VB12 level ≥ 148 pmol/L, n = 60), mostly middle-aged and elderly patients. There were no statistical differences in gender and age between the two groups. In the case group, the number of individuals with stomach disease was 13, the number of individuals with "beefy red" patch was 78, the number of individuals with oral ulcer was 29, the number of individuals with "MCV > 100fL" and "folic acid < 15.9 nmol/L" were respectively 68 and 5. All were more than that in control group (P < 0.05). The diagnostic test, "beefy red patch" has high sensitivity (0.963) but low specificity(0.883), "MCV > 100 fL" has high specificity (0.933) but low specificity (0.815), and "MCV > 100 fL combined with beefy red patch" has maximal specificity (0.950), and area under the curve (0.949). CONCLUSIONS: Visible oral "beefy red" patch combined with accessible fingertip blood MCV could improve the rate of diagnosis in VB12 deficiency, especially in the elderly in local clinics and hospitals without in-house clinical laboratories in China, which is conducive to early disease detection and treatment.

DNA hypermethylation promotes the flowering of orchardgrass during vernalization.

Vernalization, influenced by environmental factors, is an essential process associated with the productivity of temperate crops, during which epigenetic regulation of gene expression plays an important role. Although DNA methylation is one of the major epigenetic mechanisms associated with the control of gene expression, global changes in DNA methylation in the regulation of gene expression during vernalization-induced flowering of temperate plants remain largely undetermined. To characterize vernalization-associated DNA methylation dynamics, we performed whole-genome bisulfite-treated sequencing and transcriptome sequencing in orchardgrass (Dactylis glomerata) during vernalization. The results revealed that increased levels of genome DNA methylation during the early vernalization of orchardgrass were associated with transcriptional changes in DNA methyltransferase and demethylase genes. Upregulated expression of vernalization-related genes during early vernalization was attributable to an increase in mCHH in the promoter regions of these genes. Application of an exogenous DNA methylation accelerator or overexpression of orchardgrass NUCLEAR POLY(A) POLYMERASE (DgPAPS4) promoted earlier flowering, indicating that DNA hypermethylation plays an important role in vernalization-induced flowering. Collectively, our findings revealed that vernalization-induced hypermethylation is responsible for floral primordium initiation and development. These observations provide a theoretical foundation for further studies on the molecular mechanisms underlying the control of vernalization in temperate grasses.

Genome-wide identification of C2H2-type zinc finger gene family members and their expression during abiotic stress responses in orchardgrass (Dactylis glomerata).

The C2H2-type zinc finger protein (ZFP) family is one of the largest transcription factor families in the plant kingdom and its members are involved in plant growth, development, and stress responses. As an economically valuable perennial graminaceous forage crop, orchardgrass (Dactylis glomerata) is an important feedstuff resource owing to its high yield and quality. In this study, 125 C2H2-type ZFPs in orchardgrass (Dg-ZFPs) were identified and further classified by phylogenetic analysis. The members with similar gene structures were generally clustered into the same groups, with proteins containing the conserved QALGGH motif being concentrated in groups VIII and IX. Gene ontology and miRNA target analyses indicated that Dg-ZFPs likely perform diverse biological functions through their gene interactions. The RNA-seq data revealed differentially expressed genes across tissues and development phases, suggesting that some Dg-ZFPs might participate in growth and development regulation. Abiotic stress responses of Dg-ZFP genes were verified by qPCR and Saccharomyces cerevisiae transformation, revealing that Dg-ZFP125 could enhance the tolerance of yeasts to osmotic and salt stresses. Our study performed a novel systematic analysis of Dg-ZFPs in orchardgrass, providing a reference for this gene family in other grasses and revealing new insights for enhancing gene utilization.

MeJA-responsive bHLH transcription factor LjbHLH7 regulates cyanogenic glucoside biosynthesis in Lotus japonicus.

Cyanogenic glucosides (CNglcs) play an important role in plant defense response; however, the mechanism of regulation of CNglc synthesis by the external environment and endogenous hormones is largely unclear. In this study, we found that jasmonates (JAs) promoted the synthesis of CNglcs by activating the expression of CNglc biosynthesis genes in Lotus japonicus. Several differentially expressed basic helix-loop-helix (bHLH) family genes related to the synthesis of CNglcs were identified by RNA-seq. LjbHLH7 can directly activate the expression of CYP79D3 gene, the first step of CNglc synthesis, by binding to the G-box sequence of its promoter. Transgenic plants overexpressing LjbHLH7 exhibited higher relative CNglc content and enhanced insect resistance compared with the wild type. Furthermore, the transcriptional activity of LjbHLH7 was suppressed by the interaction with the L. japonicus JASMONATE-ZIM DOMAIN protein LjJAZ4. Based on these results, we propose that LjbHLH7 acts as an activator and LjJAZ4 acts as a repressor of JA-induced regulation of CNglc biosynthesis in L. japonicus.

Genome-wide identification, phylogenetic analysis, and expression analysis of the SPL gene family in orchardgrass (Dactylis glomerata L.).

SPL (SQUAMOSA promoter binding protein-like) is a plant-specific transcription factor family that contains the conserved SBP domain, which plays a vital role in the vegetative-to-reproductive phase transition, flowering development and regulation, tillering/branching, and stress responses. Although the SPL family has been identified and characterized in various plant species, limited information about it has been obtained in orchardgrass, which is a critical forage crop worldwide. In this study, 17 putative DgSPL genes were identified among seven chromosomes, and seven groups that share similar gene structures and conserved motifs were determined by phylogenetic analysis. Of these, eight genes have potential target sites for miR156. cis-Element and gene ontology annotation analysis indicated DgSPLs may be involved in regulating development and abiotic stress responses. The expression patterns of eight DgSPL genes at five developmental stages, in five tissues, and under three stress conditions were determined by RNA-seq and qRT-PCR. These assays indicated DgSPLs are involved in vegetative-to-reproductive phase transition, floral development, and stress responses. The transient expression analysis in tobacco and heterologous expression assays in yeast indicated that miR156-targeted DG1G01828.1 and DG0G01071.1 are nucleus-localized proteins, that may respond to drought, salt, and heat stress. Our study represents the first systematic analysis of the SPL family in orchardgrass. This research provides a comprehensive assessment of the DgSPL family, which lays the foundation for further examination of the role of miR156/DgSPL in regulating development and stress responses in forages grasses.

Human urine-derived stem cell-derived exosomal miR-21-5p promotes neurogenesis to attenuate Rett syndrome via the EPha4/TEK axis.

Rett syndrome (RTT) is a rare neurodevelopmental disorder that results in multiple disabilities. Exosomal microRNA (miRs) from urine-derived stem cells (USCs) have been shown to induce neurogenesis and aid in functional recovery from brain ischemia. In the present study, we sought to determine whether that exosomal miR-21-5p from USCs could promote early neural formation in a model of RTT. USCs were isolated and evaluated by flow cytometry. Exosomes were analyzed by transmission electron microscopy, tunable resistive pulse sensing (TRPS), and western blotting. PKH26 fluorescent dyes were used to observe intake of exosomes in vivo and in vitro. An RTT mouse model was treated with exosomes for behavioral studies. Dual-luciferase report gene assays were conducted to evaluate the relationship between miR-21-5p and Eph receptor A4 (EphA4). In vitro, treatment with exosomes from human urine-derived stem cells (USC-Exos) increased the percentage of neuron-specific class III beta-tubulin (Tuj1)+ nerve cells as well as the transcription levels of ß-III tubulin and doublecortin (DCX). A higher level of miR-21-5p was observed in USC-Exos, which promoted differentiation in NSCs by targeting the EPha4/TEK axis. In vivo, exosomal miR-21-5p improved the behavior, motor coordination, and cognitive ability of mice, facilitated the differentiation of NSCs in the subventricular zone of the lateral ventricle and promoted a marked rise in the number of DCX+ cells. Our data provide evidence that exosomal miR-21-5p from human USCs facilitate early nerve formation by regulating the EPha4/TEK axis.

The chromatin accessibility landscape reveals distinct transcriptional regulation in the induction of human primordial germ cell-like cells from pluripotent stem cells.

In vitro induction of human primordial germ cell-like cells (hPGCLCs) provides an ideal platform to recapitulate hPGC development. However, the detailed molecular mechanisms regulating the induction of hPGCLCs remain largely uncharacterized. Here, we profiled the chromatin accessibility and transcriptome dynamics throughout the process of hPGCLC induction. Genetic ablation of SOX15 indicated the crucial roles of SOX15 in the maintenance of hPGCLCs. Mechanistically, SOX15 exerted its roles via suppressing somatic gene expression and sustaining latent pluripotency. Notably, ETV5, a downstream regulator of SOX15, was also uncovered to be essential for hPGCLC maintenance. Finally, a stepwise switch of OCT4/SOX2, OCT4/SOX17, and OCT4/SOX15 binding motifs were found to be enriched in closed-to-open regions of human embryonic stem cells, and early- and late-stage hPGCLCs, respectively. Collectively, our data characterized the chromatin accessibility and transcriptome landscapes throughout hPGCLC induction and defined the SOX15-mediated regulatory networks underlying this process.

Interleukin-6 released by oral lichen planus myofibroblasts promotes angiogenesis.

Oral lichen planus (OLP), defined as a potential for malignant transformation, is a chronic inflammatory disease in which abnormal angiogenesis serves a role in the malignant changes of the disease. OLP-associated fibroblasts (OLP-MFs), derived from the stroma of OLP tissues, are characterized by the presence of myofibroblasts and contribute to the secretion of pro-inflammatory cytokines, which may be involved in the molecular pathogenesis of OLP. However, the associated mechanisms of angiogenesis in OLP remain unknown. The present study aimed to verify the expression of intercellular adhesion molecular 1, vascular cell adhesion molecule 1, VEGF and CD34 in OLP, and to investigate whether IL-6 secreted by OLP-MFs promoted OLP angiogenesis and the effect of its corresponding antibody inhibition. The results of the experiments demonstrated that inflammation was present and OLP upregulated the secretion of IL-6 by OLP stromal fibroblasts, thereby enhancing OLP angiogenesis. Anti-IL-6 receptor antibody inhibited OLP-stroma IL-6 signaling and suppressed OLP angiogenesis. The antibody inhibited the inflammatory response by inhibiting the secretion of inflammatory factors, including IL-6, to suppress angiogenesis and reduce disease progression, thus indicating that this could be a potential target to develop a treatment for OLP.

[Validity and reliability of the Chinese version of Mobile Phone Involvement Questionnaire in college students].

OBJECTIVE: To test the validity and reliability of the Chinese version of Mobile Phone Involvement Questionnaire (MPIQ) in college students. METHODS: We assessed the degree of phone dependence using the MPIQ among 2122 college students. One month later, 60 students were randomly selected for assessment with the MPIQ, and the ROC curve was generated to evaluate the true positive rate (sensitivity) and false positive rate at different cutoff values to determine the optimal cutoff score of the MPIQ. RESULTS: Among 98.9% of the participants who finished all the items, their MPIQ scores show a positive skew distribution and a one-factor structure. The load scores of the items ranged from 0.54 to 0.77. The Cronbach's α coefficient and the Spearman Brown split reliability were 0.84 and 0.83, respectively, the correlation coefficients between the items and total score ranged from 0.54 to 0.76, and the test-retest reliability was 0.48 (P < 0.001). At the optimal cut-off score of 32, the sensitivity and the specificity of the MPIQ were 0.634 and 0.652, respectively. CONCLUSIONS: At the optimal cut-off score of 32, the MPIQ has good validity and reliability for assessing phone dependence among college students.

Comparative transcriptome analyses reveal different mechanism of high- and low-tillering genotypes controlling tiller growth in orchardgrass (Dactylis glomerata L.).

BACKGROUND: Tillering is an important agronomic trait underlying the yields and reproduction of orchardgrass (Dactylis glomerata), an important perennial forage grass. Although some genes affecting tiller initiation have been identified, the tillering regulatory network is still largely unknown, especially in perennial forage grasses. Thus, unraveling the regulatory mechanisms of tillering in orchardgrass could be helpful in developing selective strategies for high-yield perennial grasses. In this study, we generated high-throughput RNA-sequencing data from multiple tissues of tillering stage plants to identify differentially expressed genes (DEGs) between high- and low-tillering orchardgrass genotypes. Gene Ontology and pathway enrichment analyses connecting the DEGs to tillering number diversity were conducted. RESULTS: In the present study, approximately 26,282 DEGs were identified between two orchardgrass genotypes, AKZ-NRGR667 (a high-tillering genotype) and D20170203 (a low-tillering genotype), which significantly differed in tiller number. Pathway enrichment analysis indicated that DEGs related to the biosynthesis of three classes of phytohormones, i.e., strigolactones (SLs), abscisic acid (ABA), and gibberellic acid (GA), as well as nitrogen metabolism dominated such differences between the high- and low-tillering genotypes. We also confirmed that under phosphorus deficiency, the expression level of the major SL biosynthesis genes encoding DWARF27 (D27), 9-cis-beta-carotene 9',10'-cleaving dioxygenase (CCD7), carlactone synthase (CCD8), and more axillary branching1 (MAX1) proteins in the high-tillering orchardgrass genotype increased more slowly relative to the low-tillering genotype. CONCLUSIONS: Here, we used transcriptomic data to study the tillering mechanism of perennial forage grasses. We demonstrated that differential expression patterns of genes involved in SL, ABA, and GA biosynthesis may differentiate high- and low-tillering orchardgrass genotypes at the tillering stage. Furthermore, the core SL biosynthesis-associated genes in high-tillering orchardgrass were more insensitive than the low-tillering genotype to phosphorus deficiency which can lead to increases in SL biosynthesis, raising the possibility that there may be distinct SL biosynthesis way in tillering regulation in orchardgrass. Our research has revealed some candidate genes involved in the regulation of tillering in perennial grasses that is available for establishment of new breeding resources for high-yield perennial grasses and will serve as a new resource for future studies into molecular mechanism of tillering regulation in orchardgrass.