Distinct roles of H3K27me3 and H3K36me3 in vernalization response, maintenance, and resetting in winter wheat.

Winter plants rely on vernalization, a crucial process for adapting to cold conditions and ensuring successful reproduction. However, understanding the role of histone modifications in guiding the vernalization process in winter wheat remains limited. In this study, we investigated the transcriptome and chromatin dynamics in the shoot apex throughout the life cycle of winter wheat in the field. Two core histone modifications, H3K27me3 and H3K36me3, exhibited opposite patterns on the key vernalization gene VERNALIZATION1 (VRN1), correlating with its induction during cold exposure. Moreover, the H3K36me3 level remained high at VRN1 after cold exposure, which may maintain its active state. Mutations in FERTILIZATION-INDEPENDENT ENDOSPERM (TaFIE) and SET DOMAIN GROUP 8/EARLY FLOWERING IN SHORT DAYS (TaSDG8/TaEFS), components of the writer complex for H3K27me3 and H3K36me3, respectively, affected flowering time. Intriguingly, VRN1 lost its high expression after the cold exposure memory in the absence of H3K36me3. During embryo development, VRN1 was silenced with the removal of active histone modifications in both winter and spring wheat, with selective restoration of H3K27me3 in winter wheat. The mutant of Tafie-cr-87, a component of H3K27me3 "writer" complex, did not influence the silence of VRN1 during embryo development, but rather attenuated the cold exposure requirement of winter wheat. Integrating gene expression with H3K27me3 and H3K36me3 patterns identified potential regulators of flowering. This study unveils distinct roles of H3K27me3 and H3K36me3 in controlling vernalization response, maintenance, and resetting in winter wheat.

Peptide REF1 is a local wound signal promoting plant regeneration.

Plants frequently encounter wounding and have evolved an extraordinary regenerative capacity to heal the wounds. However, the wound signal that triggers regenerative responses has not been identified. Here, through characterization of a tomato mutant defective in both wound-induced defense and regeneration, we demonstrate that in tomato, a plant elicitor peptide (Pep), REGENERATION FACTOR1 (REF1), acts as a systemin-independent local wound signal that primarily regulates local defense responses and regenerative responses in response to wounding. We further identified PEPR1/2 ORTHOLOG RECEPTOR-LIKE KINASE1 (PORK1) as the receptor perceiving REF1 signal for plant regeneration. REF1-PORK1-mediated signaling promotes regeneration via activating WOUND-INDUCED DEDIFFERENTIATION 1 (WIND1), a master regulator of wound-induced cellular reprogramming in plants. Thus, REF1-PORK1 signaling represents a conserved phytocytokine pathway to initiate, amplify, and stabilize a signaling cascade that orchestrates wound-triggered organ regeneration. Application of REF1 provides a simple method to boost the regeneration and transformation efficiency of recalcitrant crops.

TabHLH27 orchestrates root growth and drought tolerance to enhance water use efficiency in wheat.

Cultivating high-yield wheat under limited water resources is crucial for sustainable agriculture in semiarid regions. Amid water scarcity, plants activate drought response signaling, yet the delicate balance between drought tolerance and development remains unclear. Through genome-wide association studies and transcriptome profiling, we identified a wheat atypical basic helix-loop-helix (bHLH) transcription factor (TF), TabHLH27-A1, as a promising quantitative trait locus candidate for both relative root dry weight and spikelet number per spike in wheat. TabHLH27-A1/B1/D1 knock-out reduced wheat drought tolerance, yield, and water use efficiency (WUE). TabHLH27-A1 exhibited rapid induction with polyethylene glycol (PEG) treatment, gradually declining over days. It activated stress response genes such as TaCBL8-B1 and TaCPI2-A1 while inhibiting root growth genes like TaSH15-B1 and TaWRKY70-B1 under short-term PEG stimulus. The distinct transcriptional regulation of TabHLH27-A1 involved diverse interacting factors such as TaABI3-D1 and TabZIP62-D1. Natural variations of TabHLH27-A1 influence its transcriptional responses to drought stress, with TabHLH27-A1Hap-II associated with stronger drought tolerance, larger root system, more spikelets, and higher WUE in wheat. Significantly, the excellent TabHLH27-A1Hap-II was selected during the breeding process in China, and introgression of TabHLH27-A1Hap-II allele improved drought tolerance and grain yield, especially under water-limited conditions. Our study highlights TabHLH27-A1's role in balancing root growth and drought tolerance, providing a genetic manipulation locus for enhancing WUE in wheat.

Systematic identification of wheat spike developmental regulators by integrated multi-omics, transcriptional network, GWAS, and genetic analyses.

The spike architecture of wheat plays a crucial role in determining grain number, making it a key trait for optimization in wheat breeding programs. In this study, we used a multi-omic approach to analyze the transcriptome and epigenome profiles of the young spike at eight developmental stages, revealing coordinated changes in chromatin accessibility and H3K27me3 abundance during the flowering transition. We constructed a core transcriptional regulatory network (TRN) that drives wheat spike formation and experimentally validated a multi-layer regulatory module involving TaSPL15, TaAGLG1, and TaFUL2. By integrating the TRN with genome-wide association studies, we identified 227 transcription factors, including 42 with known functions and 185 with unknown functions. Further investigation of 61 novel transcription factors using multiple homozygous mutant lines revealed 36 transcription factors that regulate spike architecture or flowering time, such as TaMYC2-A1, TaMYB30-A1, and TaWRKY37-A1. Of particular interest, TaMYB30-A1, downstream of and repressed by WFZP, was found to regulate fertile spikelet number. Notably, the excellent haplotype of TaMYB30-A1, which contains a C allele at the WFZP binding site, was enriched during wheat breeding improvement in China, leading to improved agronomic traits. Finally, we constructed a free and open access Wheat Spike Multi-Omic Database (http://39.98.48.156:8800/#/). Our study identifies novel and high-confidence regulators and offers an effective strategy for dissecting the genetic basis of wheat spike development, with practical value for wheat breeding.

Transcriptome analysis of axillary buds in low phosphorus stress and functional analysis of TaWRKY74s in wheat.

BACKGROUND: Wheat is one of the main grain crops in the world, and the tiller number is a key factor affecting the yield of wheat. Phosphorus is an essential element for tiller development in wheat. However, due to decreasing phosphorus content in soil, there has been increasing use of phosphorus fertilizer, while imposing risk of soil and water pollution. Hence, it is important to identify low phosphorus tolerance genes and utilize them for stress resistance breeding in wheat. RESULTS: We subjected the wheat variety Kenong 199 (KN199) to low phosphorus stress and observed a reduced tiller number. Using transcriptome analysis, we identified 1651 upregulated genes and 827 downregulated of genes after low phosphorus stress. The differentially expressed genes were found to be enriched in the enzyme activity regulation related to phosphorus, hormone signal transduction, and ion transmembrane transport. Furthermore, the transcription factor analysis revealed that TaWRKY74s were important for low phosphorus tolerance. TaWRKY74s have three alleles: TaWRKY74-A, TaWRKY74-B, and TaWRKY74-D, and they all belong to the WRKY family with conserved WRKYGQK motifs. These proteins were found to be located in the nucleus, and they were expressed in axillary meristem, shoot apical meristem(SAM), young leaves, leaf primordium, and spikelet primordium. The evolutionary tree showed that TaWRKY74s were closely related to OsWRKY74s in rice. Moreover, TaWRKY74s-RNAi transgenic plants displayed significantly fewer tillers compared to wild-type plants under normal conditions. Additionally, the tiller numebr of the RNAi transgenic plants was also significantly lower than that of the wild-type plants under low-phosphorus stress, and increased the decrease amplitude. This suggestd that TaWRKY74s are related to phosphorus response and can affect the tiller number of wheat. CONCLUSIONS: The results of this research showed that TaWRKY74s were key genes in wheat response to low phosphorus stress, which might regulate wheat tiller number through abscisic acid (ABA) and auxin signal transduction pathways. This research lays the foundation for further investigating the mechanism of TaWRKY74s in the low phosphorus environments and is significant for wheat stress resistance breeding.

Sevoflurane attenuates myocardial ischemia/reperfusion injury by up-regulating microRNA-99a and down-regulating BRD4.

PURPOSE: It has been explored that sevoflurane (Sevo) is cardioprotective in myocardial ischemia/reperfusion injury (MI/RI) and mediates microRNA (miRNA) expression that control various physiological systems. Enlightened by that, the work was programmed to decode the mechanism of Sevo and miR-99a with the participation of bromodomain-containing protein 4 (BRD4). METHODS: MI/RImodel was established on mice. MI/RI modeled mice were exposed to Sevo or injected with miR-99a or BRD4-related vectors to identify their functions in cardiac function, pathological injury, cardiomyocyte apoptosis, inflammation, and oxidative stress in MI/RI mice. MiR-99a and BRD4 expression in myocardial tissues were tested, and their relation was further validated. RESULTS: MiR-99a was down-regulated, and BRD4 was up-regulated in MI/RI mice. Sevo up-regulated miR-99a to inhibit BRD4 expression in myocardial tissues of MI/RI mice. Sevo improved cardiac function, relieved myocardial injury, repressed cardiomyocyte apoptosis, and alleviated inflammation and oxidative stress in mice with MI/RI. MiR-99a restoration further enhanced the positive effects of Sevo on mice with MI/RI. Overexpression of BRD4 reversed up-regulation of miR-99a-induced attenuation of MI/RI in mice. CONCLUSIONS: The work delineated that Sevo up-regulates miR-99a to attenuate MI/RI by inhibiting BRD4.

Dynamic chromatin regulatory programs during embryogenesis of hexaploid wheat.

BACKGROUND: Plant and animal embryogenesis have conserved and distinct features. Cell fate transitions occur during embryogenesis in both plants and animals. The epigenomic processes regulating plant embryogenesis remain largely elusive. RESULTS: Here, we elucidate chromatin and transcriptomic dynamics during embryogenesis of the most cultivated crop, hexaploid wheat. Time-series analysis reveals stage-specific and proximal-distal distinct chromatin accessibility and dynamics concordant with transcriptome changes. Following fertilization, the remodeling kinetics of H3K4me3, H3K27ac, and H3K27me3 differ from that in mammals, highlighting considerable species-specific epigenomic dynamics during zygotic genome activation. Polycomb repressive complex 2 (PRC2)-mediated H3K27me3 deposition is important for embryo establishment. Later H3K27ac, H3K27me3, and chromatin accessibility undergo dramatic remodeling to establish a permissive chromatin environment facilitating the access of transcription factors to cis-elements for fate patterning. Embryonic maturation is characterized by increasing H3K27me3 and decreasing chromatin accessibility, which likely participates in restricting totipotency while preventing extensive organogenesis. Finally, epigenomic signatures are correlated with biased expression among homeolog triads and divergent expression after polyploidization, revealing an epigenomic contributor to subgenome diversification in an allohexaploid genome. CONCLUSIONS: Collectively, we present an invaluable resource for comparative and mechanistic analysis of the epigenomic regulation of crop embryogenesis.

Sevoflurane attenuates myocardial ischemia/reperfusion injury by up-regulating microRNA-99a and down-regulating BRD4

Purpose: It has been explored that sevoflurane (Sevo) is cardioprotective in myocardial ischemia/reperfusion injury (MI/RI) and mediates microRNA (miRNA) expression that control various physiological systems. Enlightened by that, the work was programmed to decode the mechanism of Sevo and miR-99a with the participation of bromodomain-containing protein 4 (BRD4). Methods: MI/RImodel was established on mice. MI/RI modeled mice were exposed to Sevo or injected with miR-99a or BRD4-related vectors to identify their functions in cardiac function, pathological injury, cardiomyocyte apoptosis, inflammation, and oxidative stress in MI/RI mice. MiR-99a and BRD4 expression in myocardial tissues were tested, and their relation was further validated. Results: MiR-99a was down-regulated, and BRD4 was up-regulated in MI/RI mice. Sevo up-regulated miR-99a to inhibit BRD4 expression in myocardial tissues of MI/RI mice. Sevo improved cardiac function, relieved myocardial injury, repressed cardiomyocyte apoptosis, and alleviated inflammation and oxidative stress in mice with MI/RI. MiR-99a restoration further enhanced the positive effects of Sevo on mice with MI/RI. Overexpression of BRD4 reversed up-regulation of miR-99a-induced attenuation of MI/RI in mice. Conclusions: The work delineated that Sevo up-regulates miR-99a to attenuate MI/RI by inhibiting BRD4.

Application of etomidate and propofol mixture in hematoma removal in patients with intracranial epidural hematoma.

OBJECTIVE: To innvestigate the application of etomidate and propofol mixture in the evacuation of hematoma in patients with epidural hematoma. METHODS: 98 patients with epidural hematoma were randomly divided into two groups: the joint group (n=49, anesthesia induction with etomidate and propofol) and the etomidate group (n=49, anesthesia induction with etomidate) using a random number table. Hemodynamics, stress response and cerebral oxygen metabolism were compared between the two groups at T0 (pre-anesthesia induction), T1 (after endotracheal intubation), T2 (10 min after the beginning of the operation) and T3 (the end of the operation). Adverse reactions were also analyzed. RESULTS: Compared with T0, the mean arterial pressure (MAP) at T1, T2 and T3 in the joint group decreased first and then increased, and the MAP at T1 was significantly lower than that in the etomidate group (P<0.05). Compared with T0, blood oxygen saturation of internal jugular vein bulb (SjvO2) increased in T1-T3 groups, and SjvO2 in the joint group was higher than that in the etomidate group (all P<0.05). Compared with T0, cerebral oxygen uptake rate (CERO2) in the T1-T3 groups decreased significantly, and CERO2 at T3 in the joint group was higher than that in the etomidate group (all P<0.05). Compared with T0, the levels of cortisol and superoxide dismutase (SOD) at T3 in the two groups were significantly lower, but those in the etomidate group were higher than those in the combination group (all P<0.05). There was no significant difference in the incidence of postoperative anesthesia-related adverse reactions between the two groups (P>0.05). CONCLUSION: Etomidate has less effect on hemodynamics and stress reaction during intravenous anesthesia, but its combination with propofol can improve cerebral oxygen metabolism to a certain extent with fewer adverse reactions.

Combinational transformation of three wheat genes encoding fructan biosynthesis enzymes confers increased fructan content and tolerance to abiotic stresses in tobacco.

KEY MESSAGE: Seven kinds of transgenic tobacco plants transformed with combinations of three FBE genes were obtained. The transgenic plants transformed with Ta1-SST + Ta6-SFT genes appeared to have the highest fructan or soluble sugar content and the strongest salt tolerance. Fructan is thought to be one of the important regulators involved in plant tolerance to various abiotic stresses. In this study, wheat-derived genes, Ta1-SST, Ta6-SFT, and Ta1-FFT, encoding fructan biosynthesis enzymes (FBE) were isolated and cloned into vectors modified pBI121 or pZP211. Seven different combinations of the three target genes were transformed into tobacco plants through an Agrobacterium-mediated approach, and transgenic tobacco plants were identified by PCR, ELISA, and Southern blotting. Compared with tobacco plants transformed with other six combinations of the three target genes and with wild-type plants, the transgenic plants transformed with Ta1-SST + Ta6-SFT genes contained the highest fructan and soluble sugar content. All seven types of transgenic tobacco plants displayed a much higher level of tolerance to drought, low temperature, and high salinity compared with the wild type. Differences of drought and low temperature tolerance between the transgenic plants containing a single FBE gene and those harboring two or three FBE genes were not significant, but the salt tolerance level of the transgenic plants with different FBE gene combinations from high to low was: Ta1-SST + Ta6-SFT > Ta1-SST + Ta6-SFT + Ta1-FFT > Ta1-SST + Ta1-FFT > Ta1-SFT + Ta1-FFT > single FBE gene. These results indicated that the tolerances of the transgenic tobacco plants to various abiotic stresses were associated with the transformed target gene combinations and the contents of fructan and soluble sugar contained in the transgenic plants.