Search

Abstract The deterioration and deformation of brittle rock generally appear in railway tunnels with the operation of large buried deep tunnel. To investigate the macro-micro fracture and acoustic emission evolution characteristics of brittle rock, this paper conducted the uniaxial compression, scanning electron microscope (SEM), and acoustic emission (AE) signal monitoring under different loading rates. The results showed that the loading rate has an obvious enhancement effect on mechanical parameters. The increased loading rate extends the elastic deformation and improves the bearing strength, elastic modulus and deformation modulus. The fracture patterns include shear fracture, composite fracture, and tension fracture. The oblique shear fracture is transformed into composite fracture and tension fracture with the loading rate increasing. The microscopic fracture shows that increasing loading rate inhibits the evolution of oblique shear fractures and promotes the expansion of tensile fractures. The roughness level of tensile fractures is significantly lower than that of oblique shear fracture and composite fracture. The AE parameters and deformation behavior are characterized by simultaneous evolution. The AE amplitude changes from low-level and low-density distribution to high-level and high-density distribution as the loading rate increases. The AE activity intensity of tensile fracture is significantly greater than that of oblique shear fracture and composite fracture. The warning timeliness of cumulative AE events and cumulative AE energy is generally earlier than the AE b-value under the same loading rate, and the early warning timeliness of cumulative AE events is similar to that of cumulative AE energy.

ObjectivesTo explore the effects of low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) on motor function and cortical excitability in stroke patients with different motor evoked potential (MEP) status.MethodsA total of 80 stroke patients were enrolled in this randomized controlled trial and divided into two groups according to MEP status (− or +) of lesioned hemisphere. Then, each group was randomly assigned to receive either active or sham LF-rTMS. In addition to conventional rehabilitation, all participants received 20 sessions of rTMS at 1 Hz frequency through the active or the sham coil over 4 weeks. Fugl-Meyer Assessment (FMA), National Institutes of Health Stroke Scale (NIHSS), Shoulder Abduction Finger Extension (SAFE) and Barthel Index (BI), bilateral resting motor threshold (rMT), amplitude of Motor evoked potential (MEP) and Central Motor Conduction Time (CMCT), and Interhemispheric asymmetry (IHA) were blindly assessed at baseline, 4 weeks and 8 weeks after treatment, respectively.ResultsAt 4 weeks after intervention, FMA and NIHSS changed scores in 1 Hz MEP(+) group were significantly higher than those in the other three groups (p

Variational modal decomposition (VMD) is frequently employed for both signal decomposition and extracting features; however, the decomposition outcome is influenced by the quantity of intrinsic modal functions (IMFs) and the specific parameter values of penalty factors. To tackle this issue, we propose an algorithm based on the Halton sequence and the Laplace crossover operator for the sparrow search algorithm–VMD (HLSSA-VMD) to fine-tune the parameters of VMD. First, the population initialization by the Halton sequence yields higher-quality initial solutions, which effectively addresses the issue of the algorithm’s sluggish convergence due to overlapping and the lack of diversity of the initial solutions. Second, the introduction of the Laplace crossover operator (LX) to perturb the position of the best individual in each iteration helps to prevent the algorithm from becoming ensnared in a local optimum and improves the convergence speed of the algorithm. Finally, from the simulation of 17 benchmark test functions, we found that the HLSSA exhibited superior convergence accuracy and accelerated convergence pace, as well as better robustness than the particle swarm optimization (PSO) algorithm, the whale optimization algorithm (WOA), the multiverse optimization (MVO) algorithm, and the traditional sparrow search algorithm (SSA). In addition, we verified the effectiveness of the HLSSA-VMD algorithm on two simulated signals and compared it with PSO-VMD, WOA-VMD, MVO-VMD, and SSA-VMD. The experimental findings indicate that the HLSSA-VMD obtains better parameters, confirming the superiority of the algorithm.

Abstract Background As a type of calmodulin binding protein, CAMTAs are widely involved in vegetative and reproductive processes as well as various hormonal and stress responses in plants. To study the functions of CAMTA genes in tea plants, we investigated bioinformatics analysis and performed qRT-PCR analysis of the CAMTA gene family by using the genomes of ‘ShuChaZao’ tea plant cultivar. Results In this study, 6 CsCAMTAs were identified from tea plant genome. Bioinformatics analysis results showed that all CsCAMTAs contained six highly conserved functional domains. Tissue-specific analysis results found that CsCAMTAs played great roles in mediating tea plant aging and flowering periods. Under hormone and abiotic stress conditions, most CsCAMTAs were upregulated at different time points under different treatment conditions. In addition, the expression levels of CsCAMTA1/3/4/6 were higher in cold-resistant cultivar ‘LongJing43’ than in the cold-susceptible cultivar ‘DaMianBai’ at cold acclimation stage, while CsCAMTA2/5 showed higher expression levels in ‘DaMianBai’ than in ‘LongJing43’ during entire cold acclimation periods. Conclusions In brief, the present results revealed that CsCAMTAs played great roles in tea plant growth, development and stress responses, which laid the foundation for deeply exploring their molecular regulation mechanisms.

Matcha has a unique aroma of seaweed-like, which is popular with Chinese consumers. In order to effectively understand and use matcha for drinks and tea products, we roundly analyzed the variation of main quality components of 11 matcha samples from different regions in the Chinese market. Most of matcha samples had lower ratio of tea polyphenols to amino acids (RTA), and the RTA of 9 samples of matcha was less than 10, which is beneficial to the formation of fresh and mellow taste of matcha. The total volatile compounds concentrations by HS-SPME were 1563.59 ~ 2754.09 mg/L, among which terpenoids, esters and alcohols were the top three volatile components. The total volatile compounds concentrations by SAFE was 1009.21 ~ 1661.98 mg/L, among which terpenoids, heterocyclic compounds and esters ranked the top three. The 147 volatile components with high concentration (>1 mg/L) and no difference between samples are the common odorants to the 11 samples of matcha. The 108 distinct odorants had differences among the matcha samples, which were important substances leading to the different aroma characteristics. Hierarchical cluster analysis (HCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) showed that 11 samples of matcha were well clustered according to different components. Japanese matcha (MT, MY, ML, MR, MJ) could be clustered into two categories. The aroma composition of Guizhou matcha (GM1, GM2) was similar to that of Japanese matcha, 45 volatile components (decanal, pyrazine, 3,5-diethyl-2-methyl-, 1-hexadecanol, etc. were its characteristic aroma components. The aroma characteristics of Shandong matcha and Japanese matcha (ML, MR, MJ) were similar, 15 volatile components (γ-terpinene, myrtenol, cis-3-hexenyl valerate, etc.) were its characteristic aroma components. While Jiangsu matcha and Zhejiang matcha have similar aroma characteristics due to 225 characteristic aroma components (coumarin, furan, 2-pentyl-, etc). In short, the difference of volatile components formed the regional flavor characteristics of matcha. This study clarified the compound basis of the flavor difference of matcha from different regions in the Chinese market, and provided a theoretical basis for the selection and application of matcha in drinks and tea products.

As the most common type of stroke, ischemic stroke, also known as cerebral infarction (CI), with its high mortality and disability rate, has placed a huge burden on social economy and public health. Treatment methods for CI mainly include thrombectomy, thrombolysis, drug therapy, and so on. However, these treatments have certain timeliness and different side effects. In recent years, the gut-brain axis has become a hot topic, and its role in nervous system diseases has been confirmed by increasing evidences. The intestinal microbiota, as an important part of the gut-brain axis, has a non-negligible impact on the progression of CI through mechanisms such as inflammatory response and damage-associated molecular patterns, and changes in the composition of intestinal microbiota can also serve as the basis for predicting CI. At the same time, the diagnosis of CI requires more high-throughput techniques, and the analysis method of metabolomics just fits this demand. This paper reviewed the changes of intestinal microbiota in patients within CI and the effects of the intestinal microbiota on the course of CI, and summarized the therapeutic methods of the intervention with the intestinal microbiota. Furthermore, metabolic changes of CI patients were also discussed to reveal the molecular characteristics of CI and to elucidate the potential pathologic pathway of its interference.

Drought tolerance and quality stability are important indicators to evaluate the stress tolerance of tea germplasm resources. The traditional screening method of drought resistant germplasm is mainly to evaluate by detecting physiological and biochemical indicators of tea plants under drought stresses. However, the methods are not only time consuming but also destructive. In this study, hyperspectral images of tea drought phenotypes were obtained and modeled with related physiological indicators. The results showed that: (1) the information contents of malondialdehyde, soluble sugar and total polyphenol were 0.21, 0.209 and 0.227 respectively, and the drought tolerance coefficient (DTC) index of each tea variety was between 0.069 and 0.81; (2) the comprehensive drought tolerance of different varieties were (from strong to weak): QN36, SCZ, ZC108, JX, JGY, XY10, QN1, MS9, QN38, and QN21; (3) by using SVM, RF and PLSR to model DTC (drought tolerance coefficient) data, the best prediction model was selected as MSC-2D-UVE-SVM (R2 = 0.77, RMSE = 0.073, MAPE = 0.16) for drought tolerance of tea germplasm resources, named Tea-DTC model. Therefore, the Tea-DTC model based on hyperspectral machine-learning technology can be used as a new screening method for evaluating tea germplasm resources with drought tolerance.

Light is an important environmental factor which affects plant growth, through changes of intensity and quality. In this study, monochromatic white (control), red (660 nm), and blue (430 nm) light-emitting diodes (LEDs) were used to treat tea short cuttings. The results showed the most adventitious roots in blue light treated tea cuttings, but the lowest roots in that treated by red light. In order to explore the molecular mechanism of light quality affecting adventitious root formation, we performed full-length transcriptome and metabolome analyses of mature leaves under three light qualities, and then conducted weighted gene co-expression network analysis (WGCNA). Phytohormone analysis showed that Indole-3-carboxylic acid (ICA), Abscisic acid (ABA), ABA-glucosyl ester (ABA-GE), trans-Zeatin (tZ), and Jasmonic acid (JA) contents in mature leaves under blue light were significantly higher than those under white and red light. A crosstalk regulatory network comprising 23 co-expression modules was successfully constructed. Among them, the “MEblue” module which had a highly positive correlation with ICA (R = 0.92, P = 4e-04). KEGG analysis showed that related genes were significantly enriched in the “Plant hormone signal transduction (ko04075)” pathway. YUC (a flavin-containing monooxygenase), AUX1, AUX/IAA, and ARF were identified as hub genes, and gene expression analysis showed that the expression levels of these hub genes under blue light were higher than those under white and red light. In addition, we also identified 6 auxin transport-related genes, including PIN1, PIN3, PIN4, PILS5, PILS6, and PILS7. Except PILS5, all of these genes showed the highest expression level under blue light. In conclusion, this study elucidated the molecular mechanism of light quality regulating adventitious root formation of tea short cutting through WGCNA analysis, which provided an innovation for “rapid seedling” of tea plants.

Abstract Background Autophagy, meaning ‘self-eating’, is required for the degradation and recycling of cytoplasmic constituents under stressful and non-stressful conditions, which helps to maintain cellular homeostasis and delay aging and longevity in eukaryotes. To date, the functions of autophagy have been heavily studied in yeast, mammals and model plants, but few studies have focused on economically important crops, especially tea plants (Camellia sinensis). The roles played by autophagy in coping with various environmental stimuli have not been fully elucidated to date. Therefore, investigating the functions of autophagy-related genes in tea plants may help to elucidate the mechanism governing autophagy in response to stresses in woody plants. Results In this study, we identified 35 C. sinensis autophagy-related genes (CsARGs). Each CsARG is highly conserved with its homologues from other plant species, except for CsATG14. Tissue-specific expression analysis demonstrated that the abundances of CsARGs varied across different tissues, but CsATG8c/i showed a degree of tissue specificity. Under hormone and abiotic stress conditions, most CsARGs were upregulated at different time points during the treatment. In addition, the expression levels of 10 CsARGs were higher in the cold-resistant cultivar ‘Longjing43’ than in the cold-susceptible cultivar ‘Damianbai’ during the CA period; however, the expression of CsATG101 showed the opposite tendency. Conclusions We performed a comprehensive bioinformatic and physiological analysis of CsARGs in tea plants, and these results may help to establish a foundation for further research investigating the molecular mechanisms governing autophagy in tea plant growth, development and response to stress. Meanwhile, some CsARGs could serve as putative molecular markers for the breeding of cold-resistant tea plants in future research.

Background: Porokeratosis (PK) is a rare, heterogeneous group of keratinization disorders with an autosomal dominant inheritance pattern and is characterized by the presence of cornoid lamella. Disseminated superficial actinic PK is the most encountered subtype and typically manifests as multiple, small annular plaques with atrophic centers and slightly raised hyperkeratotic edges. Seven associated mutations (SSH1, SART3, MVKP, MVK, MVD, FDPS, and SLC17A9) have been reported in disseminated superficial actinic PK patients. Aim: We searched a Chinese disseminated superficial porokeratosis (DSAP) family to detect the causative genes. In the meantime, we reviewed the articles reported about DSAP in Chinese population, summarizing their clinical manifestations and discussing the incidence of DSAP in Chinese population. Materials and Methods: Sanger sequencing on the MVD and MVK genes was performed to identify the pathogenic mutation in a Chinese family with DSAP. Literature for DSAP cases reported in Chinese populations was searched by Sinomed and PubMed. Results: We identified the c. 875A > G (p. Asn292Ser) mutation in the MVD gene in the family. Conclusions: That mutation was a hotspot mutation. Literature review showed that the age of onset in DSAP family was earlier than that in sporadic patients; the lesion is common in the face in Chinese population which is distinct from studies in Caucasians; ultraviolet exposure is the main aggravating factor.

Pectin methylesterase inhibitor (PMEI) inhibits pectin methylesterase (PME) activity at post-translation level, which plays core roles in vegetative and reproductive processes and various stress responses of plants. However, the roles of PMEIs in tea plant are still undiscovered. Herein, a total of 51 CsPMEIs genes were identified from tea plant genome. CsPMEI1-4 transcripts were varied in different tea plant tissues and regulated by various treatments, including biotic and abiotic stresses, sugar treatments, cold acclimation and bud dormancy. Overexpression of CsPMEI4 slightly decreased cold tolerance of transgenic Arabidopsis associated with lower electrolyte leakage, soluble sugars contents and transcripts of many cold-induced genes as compared to wild type plants. Under long-day and short-day conditions, CsPMEI2/4 promoted early flowering phenotypes in transgenic Arabidopsis along with higher expression levels of many flowering-related genes. Moreover, overexpression of CsPMEI2/4 decreased PME activity, but increased sugars contents (sucrose, glucose, and fructose) in transgenic Arabidopsis as compared with wild type plants under short-day condition. These results indicate that CsPMEIs are widely involved in tea plant vegetative and reproductive processes, and also in various stress responses. Moreover, CsPMEI4 negatively regulated cold response, meanwhile, CsPMEI2/4 promoted early flowering of transgenic Arabidopsis via the autonomous pathway. Collectively, these results open new perspectives on the roles of PMEIs in tea plant.

The type of adventitious root formation of tea softwood cuttings is different from that of single node cuttings. In addition to the callus at the base of cuttings, the adventitious roots are also formed in the upper cortex of softwood cuttings. In order to find out the similarities and differences between the above two types of adventitious roots of softwood cuttings and the influencing factors for the differences, an integrated analysis of plant hormones, untargeted metabolomics, and transcriptomics of the softwood cutting stems at different positions is performed. The phytohormone results show that IAA plays a leading role, and a high ratio of in vivo auxin to GA3 or ABA facilitated root formation. The ratios of IAA/GA3 and IAA/ABA in the upper and base rooting parts of cuttings are both higher than the middle non-rooting transition zone. Differences in metabolites indicate that 73 metabolites are involved in the formation of adventitious roots in cuttings. Compared with the middle non-rooting transition zone, most saccharides are downregulated in the upper and base rooting parts of softwood cuttings, and the saccharides in the base rooting parts of cuttings are more consumed than that in the upper rooting parts. Most organic acids in the callus at the base of cuttings show an upward trend, while those in the upper rooting parts show a downward trend. Furthermore, coniferyl alcohol is the key metabolite for adventitious root formation in the upper and base rooting parts of cuttings. Transcriptome results show 1099 differentially expressed genes (DEGs) are obtained, and KEGG enrichment analysis show that these DEGs are significantly enriched in phenylpropanoid biosynthesis, plant hormone signal transduction, and flavonoid biosynthesis pathways. Based on weighted gene co-expression network analysis (WGCNA), two key modules which have a highly positive correlation with IAA are identified. In summary, maintaining the balance of endogenous hormones and sufficient nutritional elements is very important for adventitious root formation in tea plants. Clarifying the material basis of softwood cutting rooting of tea plant is of great significance to improve the cutting survival rate of tea plant (especially difficult rooting varieties) and shorten the breeding cycle.

Nitrogen is essential for the growth and quality formation of tea plants. Excessive and inefficient use of nitrogen fertilizer leads to cost increases and ecosystem pollution. It is important to improve the nitrogen use efficiency (NUE) for tea plantation. Breeding high-NUE varieties by marker-assisted selection using NUE-associated genes is a viable approach. However, few molecular markers related to nitrogen uptake and utilization have been identified in tea plants. In this study, a total of 2554 SNP loci within NUE-related genes were identified in a database. Of the non-synonymous SNPs, 46 were successfully converted to KASP markers. These markers were deployed on 35 tea germplasms to assess their suitability and accuracy in genetic analysis. The results show that 42 markers exhibited polymorphisms and the PIC values ranged from 0.05 to 0.38. The clustering results of the phylogenetic tree was basically consistent with the phenotype, showing that tea germplasms with high nitrogen accumulation and large biomass were grouped into one cluster. Using these markers, the fingerprints of these germplasms were constructed. The preliminary association analysis showed that there were two SNPs (CsSNP07 and CsSNP11) within CsNRT2.4 (CSS0001304) that were significantly associated with nitrogen accumulation (F = 4.631, P = 0.039 and F = 3.054, p = 0.047) and one SNP (CsSNP40) within CsAAP6 (CSS0035405) that was significantly associated with biomass (F = 3.842, p = 0.032). These functional SNP-KASP markers will be valuable for the early evaluation of tea germplasms and could accelerate the breeding of high-NUE varieties.

Aphemia is a rare and special type of speech disorder, and the mechanisms underlying the occurrence and recovery remain unclear. Here, we present a clinical case of poor spontaneous recovery of aphemia, with the anterior segment of the left arcuate fasciculus server damaged and the posterior segment intact, as detected by diffusion tensor imaging. Aphemia could be caused by the disruption of the cortical and subcortical language circuits. In particular, our data support the view that damage to the anterior segment of the left arcuate fasciculus may result in poor spontaneous recovery from speech production deficits and that an intact posterior segment seems to be crucial for supporting residual language comprehension ability in patients with post-stroke aphasia. Collectively, these data imply the importance of the left arcuate fasciculus during recovery from the language disorder in the subacute stage of stroke.

Abstract Background Lysine crotonylation, as a novel evolutionarily conserved type of post-translational modifications, is ubiquitous and essential in cell biology. However, its functions in tea plants are largely unknown, and the full functions of lysine crotonylated proteins of tea plants in nitrogen absorption and assimilation remains unclear. Our study attempts to describe the global profiling of nonhistone lysine crotonylation in tea leaves and to explore how ammonium (NH4 +) triggers the response mechanism of lysine crotonylome in tea plants. Results Here, we performed the global analysis of crotonylome in tea leaves under NH4 + deficiency/resupply using high-resolution LC-MS/MS coupled with highly sensitive immune-antibody. A total of 2288 lysine crotonylation sites on 971 proteins were identified, of which contained in 15 types of crotonylated motifs. Most of crotonylated proteins were located in chloroplast (37%) and cytoplasm (33%). Compared with NH4 + deficiency, 120 and 151 crotonylated proteins were significantly changed at 3 h and 3 days of NH4 + resupply, respectively. Bioinformatics analysis showed that differentially expressed crotonylated proteins participated in diverse biological processes such as photosynthesis (PsbO, PsbP, PsbQ, Pbs27, PsaN, PsaF, FNR and ATPase), carbon fixation (rbcs, rbcl, TK, ALDO, PGK and PRK) and amino acid metabolism (SGAT, GGAT2, SHMT4 and GDC), suggesting that lysine crotonylation played important roles in these processes. Moreover, the protein-protein interaction analysis revealed that the interactions of identified crotonylated proteins diversely involved in photosynthesis, carbon fixation and amino acid metabolism. Interestingly, a large number of enzymes were crotonylated, such as Rubisco, TK, SGAT and GGAT, and their activities and crotonylation levels changed significantly by sensing ammonium, indicating a potential function of crotonylation in the regulation of enzyme activities. Conclusions The results indicated that the crotonylated proteins had a profound influence on metabolic process of tea leaves in response to NH4 + deficiency/resupply, which mainly involved in diverse aspects of primary metabolic processes by sensing NH4 +, especially in photosynthesis, carbon fixation and amino acid metabolism. The data might serve as important resources for exploring the roles of lysine crotonylation in N metabolism of tea plants. Data were available via ProteomeXchange with identifier PXD011610.

Objective: To investigate the correlation between the left arcuate fasciculus (AF) segments and acute/subacute post-stroke aphasia (PSA). Methods: Twenty-six patients underwent language assessment and MRI scanning. The integrity of the AF based on a three-segment model was evaluated using diffusion tensor imaging. All patients were classified into three groups according to the reconstruction of the left AF: completely reconstructed (group A, 8 cases), non-reconstructed (group B, 6 cases), and partially reconstructed (group C, 12 cases). The correlations and intergroup differences in language performance and diffusion indices were comprehensively estimated. Results: A correlation analyses showed that the lesion load of the language areas and diffusion indices on the left AF posterior and long segments was significantly related to some language subsets, respectively. When controlled lesion load was variable, significant correlations between diffusion indices on the posterior and long segments and comprehension, repetition, naming, and aphasia quotient were retained. Multiple comparison tests revealed intergroup differences in diffusion indices on the left AF posterior and long segments, as well as these language subsets. No significant correlation was found between the anterior segment and language performance. Conclusions: The integrity of the left AF segments, particularly the posterior segment, is crucial for the residual comprehension and repetition abilities in individuals with acute/subacute PSA, and lesion load in cortical language areas is an important factor that should be taken into account when illustrating the contributions of damage to special fiber tracts to language impairments.

Drought and heat stresses can influence the expressions of genes, and thereby affect the growth and development of plants. Alternative splicing (AS) of genes plays crucial roles through increasing transcriptome diversity in plant stress responses. Tea plants, widely cultivated in the tropics and subtropics, are often simultaneously exposed to drought and heat stresses. In the present study, we performed a global transcriptome of tea leaves treated with drought, heat or their combination. In total, 19,019, 20,025 and 20,253 genes underwent AS in response to drought (DT), heat (HT) and their combined stress (HD), respectively, of which 12,178, 11,912 and 14,413 genes differentially spliced in response to DT, HT and HD, respectively. Also, 2,447 specific differentially spliced genes (DSGs) were found only in response to HD. All DSGs accounted for 48% of the annotated genes in tea tree genome. Comparison of DSGs and differentially expressive genes (DEGs) showed that the proportions of HT and HD-induced DSGs were 13.4% and 9.2%, while the proportion of DT increased to 28.1%. Moreover, the DEG-DSG overlapped genes tended to be enriched in a wide large of pathways in response to DT. The results indicated that the AS of genes in tea leaves was extensively triggered by drought, heat and their combined stresses. In addition, the AS enhanced the transcriptome adaption in response to drought and heat stresses, and the AS also provoked specific molecular functions in response to drought and heat synergy stress. The study might have practical significance for molecular genetic breeding of tea plants with stress resistance.

The Trx and Grx systems, two disulfide reductase systems, play critical roles in various cell activities. There are great differences between the thiol redox systems in prokaryotes and mammals. Though fluorescent probes have been widely used to detect these systems in mammalian cells. Very few methods are available to detect rapid changes in the redox systems of prokaryotes. Here we investigated whether Fast-TRFS, a disulfide-containing fluorescent probe utilized in analysis of mammalian thioredoxin reductase, could be used to detect cellular disulfide reducibility in bacteria. Fast-TRFS exhibited good substrate qualities for both bacterial thioredoxin and GSH-glutaredoxin systems in vitro, with Trx system having higher reaction rate. Moreover, the Fast-TRFS was used to detect the disulfide reductase activity in various bacteria and redox-related gene null E. coli. Some glutaredoxin-deficient bacteria had stronger fast disulfide reducibility. The Trx system was shown to be the predominant disulfide reductase for fast disulfide reduction rather than the Grx system. These results demonstrated that Fast-TRFS is a viable probe to detect thiol-dependent disulfide reductases in bacteria. It also indicated that cellular disulfide reduction could be classified into fast and slow reaction, which are predominantly catalyzed by E. coli Trx and Grx system, respectively.

Abstract Background Vacuolar invertases (VINs) have been reported to regulate plant growth and development and respond to abiotic stresses such as drought and cold. With our best knowledge, the functions of VIN genes little have been reported in tea plant (Camellia sinensis L.). Therefore, it is necessary to develop research in this field. Results Here, we identified a VIN gene, CsINV5, which was induced by cold acclimation and sugar treatments in the tea plant. Histochemical assays results showed that the 1154 bp 5′-flanking sequence of CsINV5 drove β-glucuronidase (GUS) gene expression in roots, stems, leaves, flowers and siliques of transgenic Arabidopsis during different developmental stages. Moreover, promoter deletion analysis results revealed that an LTRE-related motif (CCGAAA) and a WBOXHVISO1 motif (TGACT) within the promoter region of CsINV5 were the core cis-elements in response to low temperature and sugar signaling, respectively. In addition, overexpression of CsINV5 in Arabidopsis promoted taproot and lateral root elongation through glucose-mediated effects on auxin signaling. Based on physiological and RNA-seq analysis, we found that overexpression of CsINV5 improved cold tolerance in transgenic Arabidopsis mainly by increasing the contents of glucose and fructose, the corresponding ratio of hexose to sucrose, and the transcription of osmotic-stress-related genes (P5CS1, P5CS2, AtLEA3, COR413-PM1 and COR15B) to adjust its osmotic potential. Conclusions Comprehensive experimental results suggest that overexpression of CsINV5 may enhance the cold tolerance of plant through the modification of cellular sugar compounds contents and osmotic regulation related pathways.

Plant defence: pathways for tea protection A comparison of gene activity in resistant and susceptible tea cultivars provides insights into mechanisms of defence against one of the most devastating tea diseases: anthracnose. Tea (Camellia sinensis) is an important crop in many tropical countries; however, yields can be devastated by the fungus Colletotrichum, the causal agent of anthracnose. Xinchao Wang and Yajun Yang, of the Chinese Academy of Sciences’ Tea Research Institute in Hangzhou, explored the defence response in tea cultivars infected with Colletotrichum. Discrepancies in the genes activated in resistant and susceptible cultivars suggest resistance is mediated by specific molecular signalling pathways, known resistance (R) genes, and involves the production of hydrogen peroxide and initiation of programmed cell death around sites of infection. These mechanisms could be harnessed to develop tea cultivars with greater resistance to anthracnose.

The tea plant (Camellia sinensis (L.) O. Kuntze) is an economically important woody species. In this study, we collected 26 tea plant samples with typical discoloration symptoms from different tea gardens and performed metagenomic analysis based on next-generation sequencing. Homology annotation and PCR sequencing validation finally identified seven kinds of plant viruses from tea plant. Based on abundance distribution analysis, the two most abundant plant viruses were highlighted. Genetic characterization suggested that they are two novel virus species with relatively high homology to Blueberry necrotic ring blotch virus and American plum line pattern virus. We named the newly discovered viruses tea plant necrotic ring blotch virus (TPNRBV) and tea plant line pattern virus (TPLPV). Evolutionary relationship analysis indicated that TPNRBV and TPLPV should be grouped into the Blunervirus and the Ilarvirus genera, respectively. TPLPV might have same genome activation process with known ilarviruses based on sequence analysis. Moreover, specific primers for both viruses detection were designed and validated. The symptoms and ultrastructure of TPNRBV infected leaves were first recorded. Virus detections in the symptomatic and asymptomatic tissues from field plants showing tea plant necrotic ring blotch disease suggest that TPNRBV has a systemic movement feature. In summary, we first identified seven kinds of putative plant viruses by metagenomic analysis and report two novel viruses being latent pathogens to tea plant. The results will advance our understanding of tea plant virology and have significance for the genetic breeding of tea plants in the future.