OsmiR528 regulates rice-pollen intine formation by targeting an uclacyanin to influence flavonoid metabolism.

The intine, the inner layer of the pollen wall, is essential for the normal development and germination of pollen. However, the composition and developmental regulation of the intine in rice (Oryza sativa) remain largely unknown. Here, we identify a microRNA, OsmiR528, which regulates the formation of the pollen intine and thus male fertility in rice. The mir528 knockout mutant aborted pollen development at the late binucleate pollen stage, significantly decreasing the seed-setting rate. We further demonstrated that OsmiR528 affects pollen development by directly targeting the uclacyanin gene OsUCL23 (encoding a member of the plant-specific blue copper protein family of phytocyanins) and regulating intine deposition. OsUCL23 overexpression phenocopied the mir528 mutant. The OsUCL23 protein localized in the prevacuolar compartments (PVCs) and multivesicular bodies (MVBs). We further revealed that OsUCL23 interacts with a member of the proton-dependent oligopeptide transport (POT) family of transporters to regulate various metabolic components, especially flavonoids. We propose a model in which OsmiR528 regulates pollen intine formation by directly targeting OsUCL23 and in which OsUCL23 interacts with the POT protein on the PVCs and MVBs to regulate the production of metabolites during pollen development. The study thus reveals the functions of OsmiR528 and an uclacyanin during pollen development.

A Natural Variant of miR397 Mediates a Feedback Loop in Circadian Rhythm.

MicroRNAs (miRNAs) are small noncoding RNAs of ∼21 nt in length, which have regulatory roles in many biological processes. In animals, proper functioning of the circadian clock, which is closely linked to the fitness of almost all living organisms, is regulated by miRNAs. However, to date, there have been no reports of the roles of miRNA in regulation of the plant circadian rhythm. Here, we report a natural variant of miR397 that lengthens the circadian period and controls flowering time in Arabidopsis (Arabidopsis thaliana). Highly conserved among angiosperms, the miRNA miR397 has two members in Arabidopsis: miR397a and miR397b. However, only miR397b significantly delayed flowering. Our results suggest that miR397b controls flowering by targeting CASEIN KINASE II SUBUNIT BETA3 (CKB3), in turn modulating the circadian period of CIRCADIAN CLOCK ASSOCIATED1 (CCA1). We further demonstrated that CCA1 directly bound to the promoter of MIR397B and suppressed its expression, forming a miR397b-CKB3-CCA1 circadian regulation feedback circuit. Evolutionary analysis revealed that miR397b is a newly evolved genetic variant in Arabidopsis, and the miR397b targeting mode may have a role in enhancing plant fitness. Our results provide evidence for miRNA-mediated circadian regulation in plants and suggest the existence of a feedback loop to manipulate plant flowering through the regulation of circadian rhythm.

Genome-Wide Analysis Identified a Set of Conserved lncRNAs Associated with Domestication-Related Traits in Rice.

Crop domestication, which gives rise to a number of desirable agronomic traits, represents a typical model system of plant evolution. Numerous genomic evidence has proven that noncoding RNAs such as microRNAs and phasiRNAs, as well as protein-coding genes, are selected during crop domestication. However, limited data shows plant long noncoding RNAs (lncRNAs) are also involved in this biological process. In this study, we performed strand-specific RNA sequencing of cultivated rice Oryza sativa ssp. japonica and O. sativa ssp. indica, and their wild progenitor O. rufipogon. We identified a total of 8528 lncRNAs, including 4072 lncRNAs in O. rufipogon, 2091 lncRNAs in japonica rice, and 2365 lncRNAs in indica rice. The lncRNAs expressed in wild rice were revealed to be shorter in length and had fewer exon numbers when compared with lncRNAs from cultivated rice. We also identified a number of conserved lncRNAs in the wild and cultivated rice. The functional study demonstrated that several of these conserved lncRNAs are associated with domestication-related traits in rice. Our findings revealed the feature and conservation of lncRNAs during rice domestication and will further promote functional studies of lncRNAs in rice.

Transcriptional landscape of pathogen-responsive lncRNAs in rice unveils the role of ALEX1 in jasmonate pathway and disease resistance.

Plant defence is multilayered and is essential for surviving in a changing environment. The discovery of long noncoding RNAs (lncRNAs) has dramatically extended our understanding of post-transcriptional gene regulation in diverse biological processes. However, the expression profile and function of lncRNAs in disease resistance are still largely unknown, especially in monocots. Here, we performed strand-specific RNA sequencing of rice leaves infected by Xanthomonas oryzae pv. Oryzae (Xoo) in different time courses and systematically identified 567 disease-responsive rice lncRNAs. Target analyses of these lncRNAs showed that jasmonate (JA) pathway was significantly enriched. To reveal the interaction between lncRNAs and JA-related genes, we studied the coexpression of them and found 39 JA-related protein-coding genes to be interplayed with 73 lncRNAs, highlighting the potential modulation of lncRNAs in JA pathway. We subsequently identified an lncRNA, ALEX1, whose expression is highly induced by Xoo infection. A T-DNA insertion line constructed using enhancer trap system showed a higher expression of ALEX1 and exerted a significant resistance to rice bacterial blight. Functional study revealed that JA signalling is activated and the endogenous content of JA and JA-Ile is increased. Overexpressing ALEX1 in rice further confirmed the activation of JA pathway and resistance to bacterial blight. Our findings reveal the expression of pathogen-responsive lncRNAs in rice and provide novel insights into the connection between lncRNAs and JA pathway in the regulation of plant disease resistance.

Haematocrit differences modify the association of cardiopulmonary bypass reoxygenation with acute kidney injury after paediatric Tetralogy of Fallot repair.

BACKGROUND: Little is known regarding the potential impact of haematocrit differences in the association between cardiopulmonary bypass reoxygenation and acute kidney injury following Tetralogy of Fallot repair. METHODS: We investigated the association of perfusate oxygenation during aortic occlusion associated with acute kidney injury between 204 normal and 248 higher haematocrit children with Tetralogy of Fallot, aged 1 month-18 years, who were surgically repaired in 2012-2018. Normal and higher haematocrit children were defined as having a preoperative haematocrit within and above age- and sex-specific reference intervals, respectively. Acute kidney injury was determined as a binary variable according to the Kidney Disease Improving Global Outcomes criteria. RESULTS: After adjusting for baseline and clinical covariates, a significant interaction between the haematocrit and continuous perfusate oxygenation on acute kidney injury was found (pinteraction = 0.049): a higher perfusate oxygenation was associated with a greater acute kidney injury risk among higher haematocrit children (adjusted odds ratio = 1.50, 95% confidence interval = [1.02, 2.22] per SD, p = 0.038) but not among normal haematocrit children (adjusted odds ratio = 0.91, 95% confidence interval = [0.51, 1.63] per SD, p = 0.73). After a similar adjustment, there was a marginal interaction between tertiles of perfusate oxygenation and haematocrit on acute kidney injury (pinteraction = 0.09): the middle and top tertiles of perfusate oxygenation were associated with a trend towards increased acute kidney injury risks among higher haematocrit children (adjusted odds ratio = 1.69, 95% confidence interval = [0.61, 4.66]; adjusted odds ratio = 2.25, 95% confidence interval = [0.84, 5.99], respectively) but not among normal haematocrit children (adjusted odds ratio = 1.16, 95% confidence interval = [0.46, 2.94]; adjusted odds ratio = 0.45, 95% confidence interval = [0.15, 1.36], respectively) compared with the bottom tertile. CONCLUSION: Preoperative haematocrit differences significantly modify the association of perfusate oxygenation with acute kidney injury, highlighting differential control of reoxygenation for different haematocrit children with Tetralogy of Fallot in the management of cardiopulmonary bypass.

Nicotine downregulates microRNA-200c to promote metastasis and the epithelial-mesenchymal transition in human colorectal cancer cells.

BACKGROUND: Cigarette smoking is the most well-established risk factor for colorectal cancer (CRC). However, the mechanisms of smoking-associated colorectal carcinogenesis are poorly understood. METHODS: The effects of prediagnosis tobacco use on clinical characteristics, overall survival (OS), and recurrence-free survival (RFS) were analyzed in 396 patients with CRC. Associations between smoking status and OS and RFS were evaluated using Cox's proportional hazards regression. Furthermore, the effects of nicotine on the CRC cell lines SW620 and HT-29 were evaluated using in vitro assays. RESULTS: "Ever smoking" was associated with elevated serum carcinoembryonic antigen, American Joint Committee on Cancer T category, metastasis, and poorer OS and RFS in patients with CRC (OS: hazard ratio [HR] = 1.74, 95% confidence interval [CI], 1.07-2.81, p = 0.025; RFS: HR = 1.66, 95% CI: 1.18-2.34, p = 0.004). MicroRNA (miR)-200c was downregulated in CRC and tumor-adjacent tissues from ever smokers compared with the corresponding tissues from never smokers with CRC. Nicotine inhibited miR-200c expression in a dose- and time-dependent manner in SW620 and HT-29 CRC cell lines. Nicotine induced cell proliferation, migration, and invasion and promoted the epithelial-mesenchymal transition in SW620 and HT-29 cells, and these effects were attenuated by overexpression of miR-200c. CONCLUSION: Our findings support the adverse effects of prediagnosis cigarette smoking on prognosis and clinical behavior in CRC. We demonstrate a novel oncogenic mechanism by which nicotine promotes growth and metastasis in CRC by downregulating miR-200c.

Therapeutic effects of the novel subtype-selective histone deacetylase inhibitor chidamide on myeloma-associated bone disease.

Histone deacetylases are promising therapeutic targets in hematological malignancies. In the work herein, we investigated the effect of chidamide, a new subtype-selective histone deacetylase inhibitor that was independently produced in China, on multiple myeloma and its associated bone diseases using different models. The cytotoxicity of chidamide toward myeloma is due to its induction of cell apoptosis and cell cycle arrest by increasing the levels of caspase family proteins p21 and p27, among others. Furthermore, chidamide exhibited significant cytotoxicity against myeloma cells co-cultured with bone mesenchymal stromal cells and chidamide-pretreated osteoclasts. Importantly, chidamide suppressed osteoclast differentiation and resorption in vitro by dephosphorylating p-ERK, p-p38, p-AKT and p-JNK and inhibiting the expression of Cathepsin K, NFATc1 and c-fos. Finally, chidamide not only prevented tumor-associated bone loss in a disseminated murine model by partially decreasing the tumor burden but also prevented rapid receptor activator of nuclear factor κ-ß ligand (RANKL)-induced bone loss in a non-tumor-bearing mouse model. Based on our results, chidamide exerted dual anti-myeloma and bone-protective effects in vitro and in vivo These findings strongly support the potential clinical use of this drug as a treatment for multiple myeloma in the near future.

Genome-Wide Analysis, Expression Profile, and Characterization of the Acid Invertase Gene Family in Pepper.

Catalytic decomposition of sucrose by acid invertases (AINVs) under acidic conditions plays an important role in the development of sink organs in plants. To reveal the function of AINVs in the development of pepper fruits, nine AINV genes of pepper were identified. Protein sequencing and phylogenetic analysis revealed that the CaAINV family may be divided into cell wall invertases (CaCWINV1⁻7) and vacuolar invertases (CaVINV1⁻2). CaAINVs contain conserved regions and protein structures typical of the AINVs in other plants. Gene expression profiling indicated that CaCWINV2 and CaVINV1 were highly expressed in reproductive organs but differed in expression pattern. CaCWINV2 was mainly expressed in buds and flowers, while CaVINV1 was expressed in developmental stages, such as the post-breaker stage. Furthermore, invertase activity of CaCWINV2 and CaVINV1 was identified via functional complementation in an invertase-deficient yeast. Optimum pH for CaCWINV2 and CaVINV1 was found to be 4.0 and 4.5, respectively. Gene expression and enzymatic activity of CaCWINV2 and CaVINV1 indicate that these AINV enzymes may be pivotal for sucrose hydrolysis in the reproductive organs of pepper.

Genome-Wide Identification, Expression, and Functional Analysis of the Alkaline/Neutral Invertase Gene Family in Pepper.

Alkaline/neutral invertase (NINV) proteins irreversibly cleave sucrose into fructose and glucose, and play important roles in carbohydrate metabolism and plant development. To investigate the role of NINVs in the development of pepper fruits, seven NINV genes (CaNINV1-7) were identified. Phylogenetic analysis revealed that the CaNINV family could be divided into α and ß groups. CaNINV1-6 had typical conserved regions and similar protein structures to the NINVs of other plants, while CaNINV7 lacked amino acid sequences at the C-terminus and N-terminus ends. An expression analysis of the CaNINV genes in different tissues demonstrated that CaNINV5 is the dominant NINV in all the examined tissues (root, stem, leaf, bud, flower, and developmental pepper fruits stage). Notably, the expression of CaNINV5 was found to gradually increase at the pre-breaker stages, followed by a decrease at the breaker stages, while it maintained a low level at the post-breaker stages. Furthermore, the invertase activity of CaNINV5 was identified by functional complementation of the invertase-deficient yeast strain SEY2102, and the optimum pH of CaNINV5 was found to be ~7.5. The gene expression and enzymatic activity of CaNINV5 suggest that it might be the main NINV enzyme for hydrolysis of sucrose during pepper fruit development.

Airway and anesthesia management in tracheoesophageal fistula closure implantation: a single-centre retrospective study.

OBJECTIVE: To review and analyze the airway and anesthesia management methods for patients who underwent endoscopic closure of tracheoesophageal fistula (TEF) and to summarize the experience of intraoperative airway management. METHOD: We searched the anesthesia information system of the First Affiliated Hospital of Nanjing Medical University for anesthesia cases of TEF from July 2020 to July 2023 and obtained a total of 34 anesthesia records for endoscopic TEF occlusion. The intraoperative airway management methods and vital signs were recorded, and the patients' disease course and follow-up records were analyzed and summarized. RESULTS: The airway management strategies used for TEF occlusion patients included nasal catheter oxygen (NCO, n = 5), high-flow nasal cannula oxygen therapy (HFNC, n = 4) and tracheal intubation (TI, n = 25). The patients who underwent tracheal intubation with an inner diameter of 5.5 mm had stable hemodynamics and oxygenation status during surgery, while intravenous anesthesia without intubation could not effectively inhibit the stress response caused by occluder implantation, which could easily cause hemodynamic fluctuations, hypoxemia, and carbon dioxide accumulation. Compared with those in the TI group, the NCO group and the HFNC group had significantly longer surgical times, and the satisfaction score of the endoscopists was significantly lower. In addition, two patients in the NCO group experienced postoperative hypoxemia. CONCLUSION: During the anesthesia process for TEF occlusions, a tracheal catheter with an inner diameter of 5.5 mm can provide a safe and effective airway management method.

Cross-Subject Emotion Recognition Brain-Computer Interface Based on fNIRS and DBJNet.

Functional near-infrared spectroscopy (fNIRS) is a noninvasive brain imaging technique that has gradually been applied in emotion recognition research due to its advantages of high spatial resolution, real time, and convenience. However, the current research on emotion recognition based on fNIRS is mainly limited to within-subject, and there is a lack of related work on emotion recognition across subjects. Therefore, in this paper, we designed an emotion evoking experiment with videos as stimuli and constructed the fNIRS emotion recognition database. On this basis, deep learning technology was introduced for the first time, and a dual-branch joint network (DBJNet) was constructed, creating the ability to generalize the model to new participants. The decoding performance obtained by the proposed model shows that fNIRS can effectively distinguish positive versus neutral versus negative emotions (accuracy is 74.8%, F1 score is 72.9%), and the decoding performance on the 2-category emotion recognition task of distinguishing positive versus neutral (accuracy is 89.5%, F1 score is 88.3%), negative versus neutral (accuracy is 91.7%, F1 score is 91.1%) proved fNIRS has a powerful ability to decode emotions. Furthermore, the results of the ablation study of the model structure demonstrate that the joint convolutional neural network branch and the statistical branch achieve the highest decoding performance. The work in this paper is expected to facilitate the development of fNIRS affective brain-computer interface.

Microstructure evolution and grain refinement of ultrasonic-assisted soldering joint by using Ni foam reinforced Sn composite solder.

In this investigation, ultrasonic-assisted soldering at 260 °C in air produced high strength and high melting point Cu connections in 60 s using Ni foam reinforced Sn composite solder. Systematically examined were the microstructure, grain morphology, and shear strength of connections made with various porosities of Ni foam composite solders. Results shown that Ni foams as strengthening phases could reinforce Sn solder effectively. The addition of Ni foam accelerated the metallurgical reaction due to great amount of liquid/solid interfaces, and refined the intermetallic compounds (IMCs) grains by ultrasonic cavitation. The joints had different IMCs by using Ni foam with different porosity. Layered (Cu,Ni)6Sn5 and (Ni,Cu)3Sn4 phases both existed in Cu/Ni60-Sn/Cu joint while only (Cu,Ni)6Sn5 IMCs grew in Cu/Ni98-Sn/Cu joint. As ultrasonic time increasing, Ni skeletons were dissolved and the IMCs were peeled off from substrates and broken into small particles. And then, the IMCs gradually dissociated into refined particles and distributed homogeneously in the whole soldering seam under cavitation effects. Herein, the Cu/Ni60-Sn/Cu joint ultrasonically soldered for 60 s exhibited the highest shear strength of 86.9 MPa, as well as a high melting point about 800 â„ƒ for the solder seam composed of Ni skeletons and Ni-Cu-Sn IMCs. The characterization indicated that the shearing failure mainly occurred in the interlayer of the soldering seam. The homogeneous distributed granular IMCs and Ni skeletons hindered the crack propagation and improved the strength of Cu alloy joints.

A major QTL identification and candidate gene analysis of watermelon fruit cracking using QTL-seq and RNA-seq.

Fruit cracking decreases the total production and the commercial value of watermelon. The molecular mechanisms of fruit cracking are unknown. In this study, 164 recombinant inbred lines (RILs) of watermelon, derived from the crossing of the WQ1 (cracking-sensitive) and WQ2 (cracking-tolerant) lines, were sequenced using specific length amplified fragment sequencing (SLAF-seq). A high-density genetic linkage map was constructed with 3,335 markers spanning 1,322.74 cM, at an average 0.40 cM across whole-genome flanking markers. The cracking tolerance capacity (CTC), depth of fruit cracking (DFC), rind thickness (RT), and rind hardness (RH) were measured for quantitative trait locus (QTL) analysis. Of the four traits analyzed, one major QTL with high phenotypic variation (41.04%-61.37%) was detected at 76.613-76.919 cM on chromosome 2, which contained 104 annotated genes. Differential gene expression analysis with RNA sequencing (RNA-seq) data between the two parents identified 4,508 differentially expressed genes (DEGs). Comparison of the genes between the QTL region and the DEGs obtained eight coexisting genes. Quantitative real-time PCR (qRT-PCR) analysis revealed that these genes were significant differentially expressed between the two parents. These results provide new insights into the identification of QTLs or genes and marker-assisted breeding in watermelon.

Ferrous Sulfate-Mediated Control of Phytophthora capsici Pathogenesis and Its Impact on Pepper Plant.

Phytophthora capsici, a destructive fungal pathogen, poses a severe threat to pepper (Capsicum annuum L.) crops worldwide, causing blights that can result in substantial yield losses. Traditional control methods often come with environmental concerns or entail substantial time investments. In this research, we investigate an alternative approach involving ferrous sulfate (FeSO4) application to combat P. capsici and promote pepper growth. We found that FeSO4 effectively inhibits the growth of P. capsici in a dose-dependent manner, disrupting mycelial development and diminishing pathogenicity. Importantly, FeSO4 treatment enhances the biomass and resistance of pepper plants, mitigating P. capsici-induced damage. Microbiome analysis demonstrates that FeSO4 significantly influences soil microbial communities, particularly fungi, within the pepper root. Metabolomics data reveal extensive alterations in the redox metabolic processes of P. capsici under FeSO4 treatment, leading to compromised cell membrane permeability and oxidative stress in the pathogen. Our study presents FeSO4 as a promising and cost-effective solution for controlling P. capsici in pepper cultivation while simultaneously promoting plant growth. These findings contribute to a deeper understanding of the intricate interactions between iron, pathogen control, and plant health, offering a potential tool for sustainable pepper production.

Two novel biallelic mutations in PSMC3IP in a patient affected by premature ovarian insufficiency.

Premature ovarian insufficiency (POI) is a heterogeneous condition occurring when a woman experiences a loss of ovarian activity before the age of 40. POI is one of the most common reproductive endocrine diseases in women of childbearing age. The present study investigated the clinical manifestations and genetic features of a Chinese patient affected by POI. Next­generation whole­exome capture sequencing with Sanger direct sequencing were applied to the proband and her clinically unaffected family members. Two novel compound heterozygous mutations were identified in PSMC3IP. The first was a splicing mutation (c.597+1G>T) that was inherited from her father, whereas the second mutation (c.268G>C p.D90H) was discovered in both her mother and younger sister. The two mutations were co­segregated with the disease phenotype in the family. In conclusion, the findings of the present study further support the key role of PSMC3IP in the etiology of POI and provide a novel insight into elucidating the mechanisms of female infertility.

Strongyloides stercoralis and cytomegalovirus coinfection in a patient with a transplanted kidney.

Cytomegalovirus is a major opportunistic infection after transplantation with significant morbidity and mortality for solid organ transplant recipients. Unrecognized infection with Strongyloides stercoralis may result in significant morbidity and mortality in immunocompromised patients. Coinfection with multiple pathogens is possible, leading to diagnostic delays, and may make treatment more challenging. We report a case of coinfection with S. stercoralis and cytomegalovirus in a kidney transplant patient that resulted in pneumonitis, gastritis, and cholecystitis.

Corrigendum: Mutations in FIGLA associated with premature ovarian insufficiency in a Chinese population.

[This corrects the article DOI: 10.3389/fmed.2021.714306.].

Significance of the dissection of common hepatic arterial lymph nodes in patients with oesophageal carcinoma: a multicentre retrospective study.

OBJECTIVES: To explore the significance of intraoperative common hepatic arterial lymph node dissection in patients with ooesophageal squamous carcinoma (ESCC) without coeliac trunk lymph node metastasis indicated by abdominal enhanced CT. METHODS: Patients aged 18-75 years who underwent oesophagectomy in three medical centres from June 2012 to June 2015, for whom R0 resection was completed and lymph node metastasis in the abdominal trunk was not identified before the operation were retrospectively analysed. The effects of the application value of common hepatic arterial lymph node dissection on survival were evaluated in patients with ESCC without coeliac trunk lymph node metastasis indicated by preoperative CT. According to the eighth version ofAmerican Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) staging, we selected patients with a Pathological Tumor Node Metastasis (pTNM) stage ranging from IA to IVA for analysis. RESULTS: Among the 816 qualified patients, 577 did not have coeliac trunk lymph node metastasis based on preoperative abdominal enhanced CT, and common hepatic arterial lymph node dissection was performed during the operation (observation group). Two hundred and thirty-nine preoperative CT examinations indicated no coeliac trunk lymph node metastasis, and common hepatic arterial lymph node dissection was not performed during the operation (control group). A multifactor Cox proportional hazards model showed no risk factors for overall survival (OS) (adjusted HR (HRadj)=0.91; p=0.404) or disease-free survival (DFS) (HRadj=0.86; p=0.179), regardless of whether common hepatic arterial lymph node dissection was performed. For patients with positive left gastric arterial lymph node metastasis, a multifactor Cox proportional hazards model indicated that common hepatic arterial lymph node dissection was a risk factor for OS (HRadj=0.63; p=0.035) and DFS (HRadj=0.58; p=0.026). CONCLUSIONS: For patients with ESCC without celiac trunk metastasis indicated by abdominal enhanced CT, common hepatic arterial lymph node dissection conferred no survival benefits. However, for patients with left gastric arterial lymph node metastasis, common hepatic arterial lymph node dissection was beneficial.

Exogenous melatonin confers cold tolerance in rapeseed (Brassica napus L.) seedlings by improving antioxidants and genes expression.

Rapeseed (Brassica napus L.) is an important oilseed crop globally. However, its growth and production are significantly influenced by cold stress. To reveal the protective role of exogenous melatonin (MEL) in cold tolerance, rapeseed seedlings were pretreated with different concentrations of MEL before cold stress. The results indicated that the survival rate was increased significantly by the MEL pretreatment under cold stress. Seedlings pretreated with 0.01 g L-1 MEL were all survived and were used to analyze the physiological characteristics and the expression level of various genes related to cold tolerance. Under cold stress, exogenous MEL significantly increased the contents of proline, soluble sugar, and soluble protein; while the malondialdehyde content was decreased by exogenous MEL under cold stress. On the other hand, the activities of antioxidant defense enzymes such as catalase, peroxidase, and superoxide dismutase were also significantly enhanced. The results also showed that MEL treatment significantly upregulated the expression of Cu-SOD, COR6.6 (cold-regulated), COR15, and CBFs (C-repeat binding factor) genes under cold stress. It was suggested exogenous MEL improved the content of osmotic regulatory substances to maintain the balance of cellular osmotic potential under cold stress and improved the scavenging capacity of reactive oxygen species by strengthening the activity of antioxidant enzymes and the cold-related genes expression.

[Variation of subtropical forest soil microbial biomass and soil microbial community functional characteristics along an urban-rural gradient]. / 亚热带森林土壤微生物生物量及群落功能特征的城乡梯度变化.

Soil microorganisms, which are sensitive to environmental changes, affect soil nutrient cycling and play an important role in the biogeochemical cycling. To understand the changes of soil microorganisms in subtropical forest across the urban-rural environmental gradient, we analyzed the differences in soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and microbial community functional diversitiy in Dashu Mountain National Forest Park (urban forest), Zipeng Mountain National Forest Park (suburban forest) in Hefei and Wanfo Mountain(rural forest) in Luan City. Results showed that soil MBC followed an order of rural natural forest (115.07 mg·kg-1) > suburban forest (101.68 mg·kg-1) > urban forest (82.73 mg·kg-1), soil MBN followed an order of rural natural forest (57.73 mg·kg-1) > urban forest (31.57 mg·kg-1) > suburban forest (29.01 mg·kg-1), soil microbial metabolic activities (AWCD), McIntosh index (U) were shown as rural natural forest > suburban forest > urban forest. The main carbon sources used by soil microbial communities in those forests were carboxylic acids, amino acids and carbohydrates, with weak utilization capacity for polyamines and polyphenols. The utilization capacity of soil microorganisms to amino acids, carboxylic acids, polymers and polyphenols followed the order of rural natural forest > suburban forest > urban forest. There were significant spatial variations in the functional characteristics of soil microbial communities under urban-rural environmental gradient, with Tween 80 and ß-methyl-D-Glucoside being the characteristic carbon sources as the influencing factors. Soil pH was significantly positively correlated with the microbial McIntosh index and AWCD value, while soil ammonium nitrogen (NH4+-N) showed a significant positive correlation with microbial Shannon diversity index and AWCD value. There was a negative correlation between the microbial Simpson index and soil nitrate nitrogen (NO3--N). Soil pH, NH4+-N and NO3--N were the main factors affecting diversity index of microbial communities. The results suggested that there were significant differences in microbial community characteristics of forest soil in urban-rural environmental gradient forests, and that the metabolic potential and functional diversity of soil microbial community in urban forests were weaker than that of natural forests.