Plant-specific histone deacetylases associate with ARGONAUTE4 to promote heterochromatin stabilization and plant heat tolerance.

High temperature causes devasting effects on many aspects of plant cells and thus enhancing plant heat tolerance is critical for crop production. Emerging studies have revealed the important roles of chromatin modifications in heat stress responses. However, how chromatin is regulated during heat stress remains unclear. We show that heat stress results in heterochromatin disruption coupled with histone hyperacetylation and DNA hypomethylation. Two plant-specific histone deacetylases HD2B and HD2C could promote DNA methylation and relieve the heat-induced heterochromatin decondensation. We noted that most DNA methylation regulated by HD2B and HD2C is lost upon heat stress. HD2B- and HD2C-regulated histone acetylation and DNA methylation are dispensable for heterochromatin maintenance under normal conditions, but critical for heterochromatin stabilization under heat stress. We further showed that HD2B and HD2C promoted DNA methylation through associating with ARGONAUTE4 in nucleoli and Cajal bodies, and facilitating its nuclear accumulation. Thus, HD2B and HD2C act both canonically and noncanonically to stabilize heterochromatin under heat stress. This study not only reveals a novel plant-specific crosstalk between histone deacetylases and key factor of DNA methylation pathway, but also uncovers their new roles in chromatic regulation of plant heat tolerance.

Identification of a Major QTL and Validation of Related Genes for Tiller Angle in Rice Based on QTL Analysis.

An ideal plant architecture is an important condition to achieve high crop yields. The tiller angle is an important and complex polygenic trait of rice (Oryza sativa L.) plant architecture. Therefore, the discovery and identification of tiller angle-related genes can aid in the improvement of crop architecture and yield. In the present study, 222 SSR markers were used to establish a high-density genetic map of rice doubled haploid population, and a total of 8 quantitative trait loci (QTLs) were detected based on the phenotypic data of the tiller angle and tiller crown width over 2 years. Among them, four QTLs (qTA9, qCW9, qTA9-1, and qCW9-1) were overlapped at marker interval RM6235-RM24288 on chromosome 9 with a large effect value regarded as a stable major QTL. The selected promising related genes were further identified by relative gene expression analysis, which gives us a basis for the future cloning of these genes. Finally, OsSAURq9, which belongs to the SMALL AUXIN UP RNA (SAUR), an auxin-responsive protein family, was selected as a target gene. Overall, this work will help broaden our knowledge of the genetic control of tiller angle and tiller crown width, and this study provides both a good theoretical basis and a new genetic resource for the breeding of ideal-type rice.

Precipitation Dominates the Allocation Strategy of Above- and Belowground Biomass in Plants on Macro Scales.

The allocation of biomass reflects a plant's resource utilization strategy and is significantly influenced by climatic factors. However, it remains unclear how climate factors affect the aboveground and belowground biomass allocation patterns on macro scales. To address this, a study was conducted using aboveground and belowground biomass data for 486 species across 294 sites in China, investigating the effects of climate change on biomass allocation patterns. The results show that the proportion of belowground biomass in the total biomass (BGBP) or root-to-shoot ratio (R/S) in the northwest region of China is significantly higher than that in the southeast region. Significant differences (p < 0.05) were found in BGBP or R/S among different types of plants (trees, shrubs, and herbs plants), with values for herb plants being significantly higher than shrubs and tree species. On macro scales, precipitation and soil nutrient factors (i.e., soil nitrogen and phosphorus content) are positively correlated with BGBP or R/S, while temperature and functional traits are negatively correlated. Climate factors contribute more to driving plant biomass allocation strategies than soil and functional trait factors. Climate factors determine BGBP by changing other functional traits of plants. However, climate factors influence R/S mainly by affecting the availability of soil nutrients. The results quantify the productivity and carbon sequestration capacity of terrestrial ecosystems and provide important theoretical guidance for the management of forests, shrubs, and herbaceous plants.

Sequentially degradable hydrogel-microsphere loaded with doxorubicin and pioglitazone synergistically inhibits cancer stemness of osteosarcoma.

Drug resistance represents one of the greatest challenges in cancer treatment. Cancer stem cells (CSCs) are thought to be the major cause of failure in cancer therapy due to their considerable resistance to most chemotherapeutic agents, resulting in tumor recurrence and eventually metastasis. Here, we report a treatment strategy for osteosarcoma using hydrogel-microspheres (Gel-Mps) complex mainly composed of collagenase (Col) and PLGA microspheres (Mps) carrying Pioglitazone (Pio) and Doxorubicin (Dox). Col was encapsulated in the thermosensitive gel to preferentially degrade tumor extracellular matrix (ECM), ensuring subsequent drug penetration, while Mps with Pio and Dox were co-delivered to synergistically inhibit tumor growth and metastasis. Our results showed that the Gel-Mps dyad functions as a highly biodegradable, extremely efficient, and low-toxic reservoir for sustained drug release, displaying potent inhibition of tumor proliferation and subsequent lung metastasis. Selective PPARγ agonist Pio reversed drug resistance to Dox by significantly down-regulating the expression of stemness markers and P-glycoprotein (P-gp) in osteosarcoma cells. The Gel@Col-Mps@Dox/Pio exhibited advanced therapeutic efficacy in vivo, demonstrating its great potential to serve a novel osteosarcoma therapy, which not only inhibits the growth of, but also attenuates the stemness of osteosarcoma. The dual effects reinforce the sensitivity and efficacy of chemotherapy.

Melatonin alleviates arsenic (As) toxicity in rice plants via modulating antioxidant defense system and secondary metabolites and reducing oxidative stress.

The Arsenic (As) load on the environment has increased immensely due to large-scale industrial and agricultural uses of As in several synthetic products, such as fertilizers, herbicides, and pesticides. Melatonin is a plant hormone that has a key role in abiotic stress inhibition, but the mechanism of resilience to As stress remains unexplored in rice plants. In this study, we determined how As affects rice plant and how melatonin facilitate As stress tolerance in rice. Here we investigated that, exogenous melatonin reduced As stress by inducing anthocyanin biosynthesis. Melatonin induced the expression of anthocyanin biosynthesis genes such as PAL, CHS, CHI, F3H, DFR, and ANS, which resulted in 1659% and 389% increases in cyanidin and delphinidin, respectively. Similarly, melatonin application significantly induced SA and ABA accumulation in response to As stress in rice plant. Application of melatonin also significantly reduced expression of PT-2 and PT-8 (transporter genes) and reduced uptake of As and its translocation to other compartments. Melatonin and As analysis revealed that melatonin application significantly reduced As contents in the melatonin-supplemented plants, suggesting that As uptake is largely dependent on either the melatonin basal level or anthocyanin in rice plants. In this study, we investigated new symptoms on leaves, which can severely damage leaves and impair photosynthesis. However, anthocyanin as a chelating agent, detoxifies As in vacuole and reduces oxidative stress induced by As.

The role of memory T cells in Echinococcus granulosus-induced sensitization.

OBJECTIVE: To investigate the changes in memory T cells and the related factors in mice by the establishment of a BALB/c mouse model of Echinococcus granulosus-induced sensitization. METHODS: A sensitized BALB/c mouse model was established by intraperitoneal injection of E. granulosus. A control group (CTRL), a nonsensitized group infected with E. granulosus (CE), and a sensitized group infected with E. granulosus (ANPC) were set up. The pathological changes in lung tissue in mice, the change in memory T cells (CD4 Tm), and the change in peripheral blood nucleated interleukin-23 (IL-23) were detected using HE staining, flow cytometry, and liquid-phase multiple protein quantification techniques, respectively. RESULTS: The individual percentage of mouse memory T cells was 9.14 ± 0.45, 25.23 ± 0.17, and 13.29 ± 0.32 in the CTRL, CE, and ANPC groups, respectively. The percentage of memory T cells in the ANPC group was higher than that in the CTRL group (t = 18.410, p < .001) but lower than that in the CE group (t = -80.147, p < .001). The levels of IL-23 in peripheral blood of mice in the CTRL, CE, and ANPC groups were 225.76 ± 27.16, 359.21 ± 28.67, and 215.69 ± 22.69, respectively. The level of IL-23 in peripheral blood of mice in the ANPC group was lower than that in the CE group (t = 9.609, p < .001), and there was no statistical difference with the CTRL group (t = 0.697, p = .502). CONCLUSION: In the BALB/c mouse model of E. granulosus-induced sensitization, the expression of IL-23 in peripheral blood increased, and the memory T cell proliferated and became activated; there was a decrease in the content of IL-23 in peripheral blood and number of activated memory T cells in the sensitization group infected with E. granulosus. The E. granulosus-induced allergic reaction was related to IL-23 and the activation of memory T cells.

Identification of One Major QTL and a Novel Gene OsIAA17q5 Associated with Tiller Number in Rice Using QTL Analysis.

Rice tillers are one of the most important traits for the yield and development of rice, although little is known about its mode of inheritance. Tiller numbers were recorded every 7 days a total of nine times, starting 30 days after transplantation. Quantitative trait locus (QTL) based analysis on a set of double haploid population derivatives of a cross between the Cheongcheong and Nagdong varieties identified a major effect of locus RM18130-RM3381 on chromosome 5, which was expressed in eight different growth stages. Within the target region RM18130-RM3381 (physical distance: 2.08 Mb), 61 candidate genes were screened by annotation. Among the candidate genes, Os05g0230700 (named OsIAA17q5), which belongs to the family of auxin-responsive genes, was selected as a target. Auxin promotes cell division and meristem maintenance and is an effective plant regulator which influences plant growth and development by altering the expression of various genes. OsIAA17q5 is expected to control the number of tillers. The present study provides further understanding of the basic genetic mechanisms that selectively express the control of tiller numbers in different growth stages, as well as provides valuable information for future research aimed at cloning the target gene. These results may contribute to developing a comprehensive understanding of the basic genetic processes regulating the developmental behavior of tiller numbers in rice.

Genotype and Phenotype Interaction between OsWKRYq6 and BLB after Xanthomonas oryzae pv. Oryzae Inoculation in the Field.

Bacterial leaf blight (BLB) is an important and devastating rice disease caused by the pathogen Xanthomonas oryzae pv. Oryzae (Xoo). In particular, in recent years, the occurrence of abnormal climate and warming phenomena has produced a good environment for the occurrence of BLB, and the rice yield due to the occurrence of BLB continues to decrease. Currently, molecular breeding is applied by searching for resistant genes to development of BLB resistance cultivar. In addition, there are many methods for screening resistant genes, and among them, phenotype analysis in the field and applied research is rarely conducted. Due to recent rapid climate change, BLB is a major problem that has a more serious negative effect on rice yield. Therefore, we suggest OsWRKYq6 to be effectively used for breeding BLB-resistant cultivars by screening BLB-resistant genes. In this study, the BLB-resistant gene was screened using the lesion length, which most definitely changes to the phenotype when Xoo is infected. OsWRKYq6 was finally selected as a BLB resistance gene by analyzing the phenotype and genotype after inoculating Xoo in 120 Cheongcheong/Nagdong double haploid (CNDH) lines in the field. After Xoo inoculation, lesion length and yield were investigated, and 120 CNDH lines were divided from BLB-resistant and susceptible lines. Moreover, when the transcription level of OsWRKYq6 was analyzed in the resistant and susceptible lines after Xoo inoculation in the field, the expression level was regulated to a high level in the resistant line. In this study, we propose OsWRKYq6 as a transcription factor involved in BLB resistance. Currently, the differentiation of various races is proceeding rapidly due to rapid climate change. In addition, screening of transcription factor genes involved in BLB resistance in the field can be effectively applied to molecular breeding to develop resistant cultivars in preparation for rapid climate change.

Classification of 17 species Aegilops using DNA barcoding and SNPs, reveals gene flow among Aegilops biuncialis, Aegilops juvenalis, and Aegilops columnaris.

Rapid changes in agricultural environments caused by global warming pose a major challenge to food production and safety. Common wheat (Triticum aestivum) is a hexaploid plant (AABBDD) that shares large numbers of quantitative traits and resistance genes with B and D genomes of Aegilops species, which are responsible for several metabolic functions and biosynthetic processes, particularly in plant adaptation to biotic as well as abiotic stresses. Comparatively, the abundance of the Aegilops gene pool is much higher than that of Triticum. Therefore, we used four universal DNA barcodes for plants (ITS2, matK, rbcL, and psbM-petN) to construct a phylogenetic tree to classify the genus Aegilops. Fourteen species were distinguished among a total of 17 representative species. Aegilops biuncialis, Aegilops juvenalis, and Aegilops umbellulata could not be grouped into any of the clusters in the phylogenetic tree, indicating that these three species could not be distinguished by four DNA barcodes. Therefore, from 2408 SNPs obtained using genotyping by sequencing (GBS), we manually screened 30 SNPs that could be potentially used to classify these three species. The results of gene flow and genetic differentiation index (Fst) showed that the genetic differentiation among the three species was small, and there was bidirectional horizontal gene transfer between the three species, which was consistent with our results that the three species were difficult to classify by DNA barcode.

A Cold-Shock Protein from the South Pole-Dwelling Soil Bacterium Arthrobacter sp. Confers Cold Tolerance to Rice.

Low temperature is a critical environmental factor restricting the physiology of organisms across kingdoms. In prokaryotes, cold shock induces the expression of various genes and proteins involved in cellular processes. Here, a cold-shock protein (ArCspA) from the South Pole-dwelling soil bacterium Arthrobacter sp. A2-5 was introduced into rice, a monocot model plant species. Four-week-old 35S:ArCspA transgenic rice plants grown in a cold chamber at 4 °C survived for 6 days. Cold stress significantly decreased the chlorophyll content in WT plants after 4 days compared with that in 35S:ArCspA transgenic plants. RNA-seq analysis was performed on WT and 35S:ArCspA transgenic rice with/without cold stress. GO terms such as "response to stress (GO:0006950)", "response to cold (GO:0009409)", and "response to heat (GO:0009408)" were significantly enriched among the upregulated genes in the 35S:ArCspA transgenic rice under normal conditions, even without cold-stress treatment. The expression of five cold stress-related genes, Rab16B (Os11g0454200), Rab21 (Os11g0454300), LEA22 (Os01g0702500), ABI5 (Os01 g0859300), and MAPK5 (Os03g0285800), was significantly upregulated in the transgenic rice compared with the WT rice. These results indicate that the ArCspA gene might be involved in the induction of cold-responsive genes and provide cold tolerance.

Applying HPLC to Screening QTLs for BLB Resistance in Rice.

Bacterial leaf blight (BLB) is caused by Xanthomonas oryzae pv. oryzae and is a major cause of rice yield reductions around the world. When diseased, plants produce a variety of metabolites to resist pathogens. In this study, the various defense metabolites were quantified using high-performance liquid chromatography (HPLC) after Xoo inoculation in a 120 Cheongcheong/Nagdong double haploid (CNDH) population. Quantitative trait locus (QTL) mapping was conducted using the concentration of the plant defense metabolites. HPLC analyzes the concentration of substances according to the severity of disease symptoms. Searching for BLB resistance candidate genes by applying this analysis method is very effective when mapping related genes. These resistance genes can be mapped directly to the causative pathogens. A total of 17 metabolites were detected by means of HPLC analysis after Xoo inoculation in the 120 CNDH population. QTL mapping of the metabolite concentrations resulted in the detection of the BLB resistance candidate gene, OsWRKYq6, in RM3343 of chromosome 6. OsWRKYq6 has a very high homology sequence with WRKY transcription factor 39, and when inoculated with Xoo, the relative expression level of the resistant population was higher than that of the susceptible population. Resistance genes have previously been detected using only phenotypic change data. In this study, resistance candidate genes were detected using the concentration of metabolites produced in plants after inoculation with pathogens. This newly developed analysis method can be used to effectively detect and identify genes directly involved in disease resistance for future studies.

The Quantitative Trait Loci Mapping of Rice Plant and the Components of Its Extract Confirmed the Anti-Inflammatory and Platelet Aggregation Effects In Vitro and In Vivo.

Unpredictable climate change might cause serious lack of food in the world. Therefore, in the present world, it is urgent to prepare countermeasures to solve problems in terms of human survival. In this research, quantitative trait loci (QTLs) were analyzed when rice attacked by white backed planthopper (WBPH) were analyzed using 120 Cheongcheong/Nagdong double haploid lines. Moreover, from the detected QTLs, WBPH resistance-related genes were screened in large candidate genes. Among them, OsCM, a major gene in the synthesis of Cochlioquinone-9 (cq-9), was screened. OsCM has high homology with the sequence of chorismate mutase, and exists in various functional and structural forms in plants that produce aromatic amino acids. It also induces resistance to biotic stress through the synthesis of secondary metabolites in plants. The WBPH resistance was improved in rice overexpressed through map-based cloning of the WBPH resistance-related gene OsCM, which was finally detected by QTL mapping. In addition, cq-9 increased the survival rate of caecal ligation puncture (CLP)-surgery mice by 60%. Moreover, the aorta of rat treated with cq-9 was effective in vasodilation response and significantly reduced the aggregation of rat platelets induced by collagen treatment. A cq-9, which is strongly associated with resistance to WBPH in rice, is also associated with positive effect of CLP surgery mice survival rate, vasodilation, and significantly reduced rat platelet aggregation induced by collagen treatment. Therefore, cq-9 presents research possibilities as a substance in a new paradigm that can act on both Plant-Insect in response to the present unpredictable future.

Application of dexmedetomidine-assisted intravertebral anesthesia in hip replacement and its influence on T-lymphocyte subsets.

Application of dexmedetomidine-assisted intravertebral anesthesia for elderly patients with hip replacement and its influences on T-lymphocyte subsets in peripheral blood were assessed. Eighty-six patients undergoing intravertebral anesthesia in hip replacement were treated as group A, and one hundred patients undergoing intravertebral anesthesia combined with dexmedetomidine were treated as group B. Hemodynamic changes in both groups were compared 5 min before anesthesia (T0), immediately after skin incision (T1) and after surgery (T2). General operation conditions of patients in both groups were recorded. T-lymphocyte subsets, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), visual analogue scale (VAS) pain scores and mini-mental state examination (MMSE) cognitive function changes before surgery and 24 h after surgery were compared between the groups, and the incidence of complications in both groups after 24 h was recorded. The recovery time of patients in group B was shorter than that of group A (P<0.05). Changes of systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate fluctuations in group B were lower than those in group A (P<0.05). At 24 h after surgery, VAS scores of group B were lower than those of group A (P<0.05); levels of IL-6 and TNF-α were lower than those of group A (P<0.05); CD3+ cells, CD4+ cells, CD8+ cells, and CD4/CD8 ratio were higher than those of group A (P<0.05), and MMSE score was higher than that of group A (P<0.05). The incidence of gastrointestinal reactions and postoperative cognitive dysfunction (POCD) in group B was lower than that in group A (P<0.05). In conclusion, administration of dexmedetomidine can effectively shorten the recovery time of patients, stabilize intraoperative hemodynamics of patients, protect immune function, and reduce postoperative pain and POCD occurrence during anesthesia of hip replacement.

Protective efficacy of combined use of parecoxib and dexmedetomidine on postoperative hyperalgesia and early cognitive dysfunction after laparoscopic cholecystectomy for elderly patients.

PURPOSE: To investigate efficacy of combined use of parecoxib and dexmedetomidine on postoperative pain and early cognitive dysfunction after laparoscopic cholecystectomy for elderly patients. METHODS: The present prospective randomized controlled study included a total of 80 patients who underwent laparoscopic cholecystectomy surgery during January 2016 to November 2017 in our hospital. All patients were randomly divided into 4 groups, the parecoxib group, the dexmedetomidine group, the parecoxib and dexmedetomidine combined group, and the control group. Demographic data and clinical data were collected. Indexes of heart rate (HR), mean arterial pressure (MAP), levels of jugular venous oxygen saturation (SjvO2) and jugular venous oxygen pressure (PjvO2) were recorded at different time points before and during the surgery. The mini-mental state examination (MMSE) score, Ramsay score and Visual Analogue Score (VAS) were measured. RESULTS: Levels of both SjvO2 and PjvO2 were significantly higher in parecoxib group, dexmedetomidine group and the combined group than the control group. Meanwhile, levels of both SjvO2 and PjvO2 in the combined group were the highest. VAS scores were significantly lower in the combined group than all other groups, and total patient controlled intravenous analgesia (PCIA) pressing times within 48 h after surgery were the lowest in the combined group. Both Ramsay and MMSE scores were the highest in the combined group compared with other groups, while were the lowest in the control group. CONCLUSION: The combined use of parecoxib and dexmedetomidine could reduce the postoperative pain and improve the postoperative sedation and cognitive conditions of patients after laparoscopic cholecystectomy.

Protective efficacy of combined use of parecoxib and dexmedetomidine on postoperative hyperalgesia and early cognitive dysfunction after laparoscopic cholecystectomy for elderly patients

Abstract Purpose: To investigate efficacy of combined use of parecoxib and dexmedetomidine on postoperative pain and early cognitive dysfunction after laparoscopic cholecystectomy for elderly patients. Methods: The present prospective randomized controlled study included a total of 80 patients who underwent laparoscopic cholecystectomy surgery during January 2016 to November 2017 in our hospital. All patients were randomly divided into 4 groups, the parecoxib group, the dexmedetomidine group, the parecoxib and dexmedetomidine combined group, and the control group. Demographic data and clinical data were collected. Indexes of heart rate (HR), mean arterial pressure (MAP), levels of jugular venous oxygen saturation (SjvO2) and jugular venous oxygen pressure (PjvO2) were recorded at different time points before and during the surgery. The mini-mental state examination (MMSE) score, Ramsay score and Visual Analogue Score (VAS) were measured. Results: Levels of both SjvO2 and PjvO2 were significantly higher in parecoxib group, dexmedetomidine group and the combined group than the control group. Meanwhile, levels of both SjvO2 and PjvO2 in the combined group were the highest. VAS scores were significantly lower in the combined group than all other groups, and total patient controlled intravenous analgesia (PCIA) pressing times within 48 h after surgery were the lowest in the combined group. Both Ramsay and MMSE scores were the highest in the combined group compared with other groups, while were the lowest in the control group. Conclusion: The combined use of parecoxib and dexmedetomidine could reduce the postoperative pain and improve the postoperative sedation and cognitive conditions of patients after laparoscopic cholecystectomy.