Positive contributions of the stem to the formation of white tea quality-related metabolites during withering.

Most teas, including white tea, are produced from tender shoots containing both leaf and stem. However, the effect of the stem on white tea quality remains unclear, especially during withering, an essential process. Therefore, this study investigated the withering-induced changes in the leaves and stems of Camellia sinensis cv. 'Fudingdabai' by multi-group analysis. During withering, the levels of catechin and theobromine (i.e., major flavor-related compounds) decreased slightly, mainly in the leaves. The abundance of some proteinaceous amino acids related to fresh taste increased in stems due to increased protein hydrolysis. In addition, changes in biosynthetic pathways caused a decrease in theanine (a major non-proteinaceous amino acid) and an increase in gamma-aminobutyric acid in stems. Terpenes, mainly in the stems, were partially affected by withering. Phenylacetaldehyde, a major contributor to white tea aroma, increased mainly in the stems. These findings reflect the positive contribution of the stem to white tea quality.

Metabolic improvements of novel microbial fermentation on black tea by Eurotium cristatum.

Due to its traditional fermentation, there are obvious limits on the quality improvements in black tea. However, microbial fermentation can provide an abundance of metabolites and improve the flavor of tea. The "golden flower" fungi are widely used in the microbial fermentation of tea and has unique uses in healthcare. To further explore the improvements in black tea quality achieved via microbial fermentation, we used widely targeted metabolomics and metagenomics analyses to investigate the changes in and effects of metabolites and other microorganisms during the interaction between the "golden flower" fungi and black tea. Five key flavor metabolites were detected, the levels of catechin, epigallocatechin gallate, (-)-epicatechin gallate were decreased by different degrees after the inoculation of the "golden flower" fungus, whereas the levels of caffeine and (+)-gallocatechin increased. Botryosphaeriaceae, Botryosphaeriales, Dothideomycetes, Aspergillaceae, Trichocomaceae, and Lecanoromycetes play a positive role in the black tea fermentation process after inoculation with the "golden flower" fungi. D-Ribose can prevent hypoxia-induced apoptosis in cardiac cells, and it shows a strong correlation with Botryosphaeriaceae and Botryosphaeriales. The interaction between microorganisms and metabolites is manifested in tryptophan metabolism, starch and sucrose metabolism, and amino sugar and nucleotide sugar metabolism. In conclusion, the changes in metabolites observed during the fermentation of black tea by "golden flower" fungi are beneficial to human health. This conclusion extends the knowledge of the interaction between the "golden flower" fungi and black tea, and it provides important information for improving the quality of black tea.

Synergistic Ion-Anchoring Passivation for Perovskite Solar Cells with Efficiency Exceeding 24% and Ultra-Ambient Stability.

The high-density defect states existing at the grain boundaries and heterojunction interfaces induce nonradiative charge recombination and ion migration processes within perovskite film, which seriously impair the device efficiency and stability. Here, we propose a novel synergistic ion-anchoring passivation (SIP) strategy for high-performance perovskite solar cells, by designing a multifunctional molecule to heal the charged defects via electrostatic interactions. The anion and cation species of the multifunctional molecule are rationally screened via high-throughput DFT simulation and experimental verification, which act as efficient surface passivation agents to heal the lead- and iodine-related defects. As a result, the defect-less perovskite films deliver encouraging device power conversion efficiency >24% with negligible hysteresis. A remarkable open-circuit voltage (Voc) of 1.17 V was obtained with a Voc deficit of 370 mV, featuring the outstanding defect-passivation capability of the SIP strategy. Moreover, the SIP-treated devices show exceptional ambient stability and maintain 70% of the initial efficiency after 150 h of high humidity exposure (relative humidity 70%-80%). Our results highlight the importance of the rational design of passivation agents to realize high-performance perovskite electronics.

Dynamic change of tea (Camellia sinensis) leaf cuticular wax in white tea processing for contribution to tea flavor formation.

Despite some studies on tea leaf cuticular wax, their component changes during dehydration and withering treatments in tea processing and suspected relation with tea flavor quality formation remain unknown. Here, we showed that tea leaf cuticular wax changed drastically in tea leaf development, dehydration, or withering treatment during tea processing, which affected tea flavor formation. Caffeine was found as a major component of leaf cuticular wax. Caffeine and inositol contents in leaf cuticular wax increased during dehydration and withering treatments. Comparisons showed that tea varieties with higher leaf cuticular wax loading produced more aroma than these with lower cuticular wax loading, supporting a positive correlation between tea leaf cuticular wax loading and degradation with white tea aroma formation. Dehydration or withering treatment of tea leaves also increased caffeine and inositol levels in leaf cuticular wax and triggered cuticular wax degradation into various molecules, that could be related to tea flavor formation. Thus, tea leaf cuticular waxes not only protect tea plants but also contribute to tea flavor formation. The study provides new insight into the dynamic changes of tea leaf cuticular waxes for tea plant protection and tea flavor quality formation in tea processing.

Molecular and physiological mechanisms of tea (Camellia sinensis (L.) O. Kuntze) leaf and root in response to nitrogen deficiency.

BACKGROUND: As an economically important crop, tea is strongly nitrogen (N)-dependent. However, the physiological and molecular mechanisms underlying the response of N deficiency in tea are not fully understood. Tea cultivar "Chunlv2" [Camellia sinensis (L.) O. Kuntze] were cultured with a nutrient solution with 0 mM [N-deficiency] or 3 mM (Control) NH4NO3 in 6 L pottery pots containing clean river sands. RESULTS: N deficiency significantly decreased N content, dry weight, chlorophyll (Chl) content, L-theanine and the activities of N metabolism-related enzymes, but increased the content of total flavonoids and polyphenols in tea leaves. N deficiency delayed the sprouting time of tea buds. By using the RNA-seq technique and subsequent bioinformatics analysis, 3050 up-regulated and 2688 down-regulated differentially expressed genes (DEGs) were isolated in tea leaves in response to N deficiency. However, only 1025 genes were up-regulated and 744 down-regulated in roots. Gene ontology (GO) term enrichment analysis showed that 205 DEGs in tea leaves were enriched in seven GO terms and 152 DEGs in tea roots were enriched in 11 GO items based on P < 0.05. In tea leaves, most GO-enriched DEGs were involved in chlorophyll a/b binding activities, photosynthetic performance, and transport activities. But most of the DEGs in tea roots were involved in the metabolism of carbohydrates and plant hormones with regard to the GO terms of biological processes. N deficiency significantly increased the expression level of phosphate transporter genes, which indicated that N deficiency might impair phosphorus metabolism in tea leaves. Furthermore, some DEGs, such as probable anion transporter 3 and high-affinity nitrate transporter 2.7, might be of great potential in improving the tolerance of N deficiency in tea plants and further study could work on this area in the future. CONCLUSIONS: Our results indicated N deficiency inhibited the growth of tea plant, which might be due to altered N metabolism and expression levels of DEGs involved in the photosynthetic performance, transport activity and oxidation-reduction processes.

Analysis of the Genetic Diversity in Tea Plant Germplasm in Fujian Province Based on Restriction Site-Associated DNA Sequencing.

Fujian province, an important tea-producing area in China, has abundant tea cultivars. To investigate the genetic relationships of tea plant cultivars in Fujian province and the characteristics of the tea plant varieties, a total of 70 tea cultivars from Fujian and other 12 provinces in China were subjected to restriction site-associated DNA sequencing (RAD-seq). A total of 60,258,975 single nucleotide polymorphism (SNP) sites were obtained. These 70 tea plant cultivars were divided into three groups based on analyzing the phylogenetic tree, principal component, and population structure. Selection pressure analysis indicated that nucleotide diversity was high in Southern China and genetically distinct from cultivars of Fujian tea plant cultivars, according to selection pressure analysis. The selected genes have significant enrichment in pathways associated with metabolism, photosynthesis, and respiration. There were ten characteristic volatiles screened by gas chromatography-mass spectrometry (GC-MS) coupled with multivariate statistical methods, among which the differences in the contents of methyl salicylate, 3-carene, cis-3-hexen-1-ol, (E)-4-hexen-1-ol, and 3-methylbutyraldehyde can be used as reference indicators of the geographical distribution of tea plants. Furthermore, a metabolome genome-wide association study (mGWAS) revealed that 438 candidate genes were related to the aroma metabolic pathway. Further analysis showed that 31 genes of all the selected genes were screened and revealed the reasons for the genetic differences in aroma among tea plant cultivars in Fujian and Southern China. These results reveal the genetic diversity in the Fujian tea plants as well as a theoretical basis for the conservation, development, and utilization of the Fujian highly aromatic tea plant cultivars.

Integrated Analysis of Metabolome and Transcriptome Revealed Different Regulatory Networks of Metabolic Flux in Tea Plants [Camellia sinensis (L.) O. Kuntze] with Varied Leaf Colors.

Leaf color variations in tea plants were widely considered due to their attractive phenotypes and characteristic flavors. The molecular mechanism of color formation was extensively investigated. But few studies focused on the transformation process of leaf color change. In this study, four strains of 'Baijiguan' F1 half-sib generation with similar genetic backgrounds but different colors were used as materials, including Green (G), Yellow-Green (Y-G), Yellow (Y), and Yellow-Red (Y-R). The results of broadly targeted metabolomics showed that 47 metabolites were differentially accumulated in etiolated leaves (Y-G, Y, and Y-R) as compared with G. Among them, lipids were the main downregulated primary metabolites in etiolated leaves, which were closely linked with the thylakoid membrane and chloroplast structure. Flavones and flavonols were the dominant upregulated secondary metabolites in etiolated leaves, which might be a repair strategy for reducing the negative effects of dysfunctional chloroplasts. Further integrated analysis with the transcriptome indicated different variation mechanisms of leaf phenotype in Y-G, Y, and Y-R. The leaf color formation of Y-G and Y was largely determined by the increased content of eriodictyol-7-O-neohesperidoside and the enhanced activities of its modification process, while the color formation of Y-R depended on the increased contents of apigenin derivates and the vigorous processes of their transportation and transcription factor regulation. The key candidate genes, including UDPG, HCT, CsGSTF1, AN1/CsMYB75, and bHLH62, might play important roles in the flavonoid pathway.

ß-tricalcium phosphate/gelatin composite scaffolds incorporated with gentamycin-loaded chitosan microspheres for infected bone defect treatment.

The repair of infected bone defects remains a clinical challenge. Staphylococcus aureus is a common pathogenic micro-organism associated with such infections. Gentamycin (GM) is a broad spectrum antibiotic that can kill S. aureus in a dose-dependent manner. However, the systemic administration of antibiotics may lead to drug resistance and gut dysbiosis. In this work, we constructed ß-tricalcium phosphate/gelatin composite scaffolds incorporated with gentamycin-loaded chitosan microspheres (CMs(GM)-ß-TCP/gelatin composite scaffolds), which helped optimize the local GM release in the infected defect areas and enhance bone regeneration. The cumulative release curves showed that both microspheres and composite scaffolds reached a sustained slow-release phase after the initial rapid release, and the latter further stabilized the initial drug release rate. The release curve of CMs(GM)-ß-TCP/gelatin composite scaffolds reached a plateau after 24 h, and the cumulative release reached 41.86% during this period. Moreover, the combination of ß-TCP and gelatin mimicked bone composition and were able to provide the requisite mechanical strength (0.82 ± 0.05 MPa) during the first phase of bone generation. The inner structure of the scaffold was arranged in the shape of interconnected pores, and presented a porosity level of 16%. The apertures were uniform in size, which was beneficial for cell proliferation and material transportation. Macroscopic observation and histological analysis showed that CMs(GM)-ß-TCP/gelatin composite scaffolds fused with bone tissues, and new tissues were formed in defect areas without any infection. This new composite scaffold may be a promising repair material for treating infected bone defects.

Impact of soft tissue around the knee on the efficacy of extracorporeal shockwave therapy in knee osteoarthritis.

Knee osteoarthritis (KOA) is the leading cause of knee pain in middle-aged and older individuals. Extracorporeal shockwave therapy (ESWT) has been applied to treat patients with KOA to reduce pain and improve function. Patients (n = 123) diagnosed with KOA who received ESWT were selected to participate in this study, and were grouped according to their body mass index (BMI). The treatment parameters were as follows: 8000 pulses, 2.0 bar, 0.25 mJ/mm2, and 6 Hz/s once per week for 8 weeks. The visual analog scale (VAS), Lequesne index, and Western Ontario and McMaster University Osteoarthritis Index (WOMAC) were measured to assess knee pain and functional recovery according to BMI groups. Radiographs were used to measure the richness of the soft tissue around the knee joint. The correlation between the distribution of tissue, pain, and functional improvement was analyzed using the receiver operator characteristic curve. All the patients showed a reduction in pain after treatment compared to that before treatment (P < .01). As measured by the VAS, the Lequesne and WOMAC indexes, after the intervention, the pain and functional index of the overweight and above BMI group improved to a greater extent than that of the normal or below normal BMI group (P < .01). The area under the curve showed, with VAS as the demarcation criterion, when the tibial plateau soft tissue ratio, femoral intercondylar apex soft tissue ratio, and medial tibial soft tissue ratio exceeded 1.538, 1.534, and 1.296, respectively, the patient's pain relief was more pronounced the ESWT treatment was better. With pain in WOMAC as the demarcation criterion, the tibial plateau soft tissue ratio, femoral intercondylar apex soft tissue ratio, and medial tibial soft tissue ratio also are positively correlated with pain relief in patients. When the Lequesne and WOMAC scores were the demarcation criteria, the patients' function improved significantly when the patella apical soft tissue ratio exceeded 2.401 and 2.635, respectively. ESWT can effectively alleviate pain and improve knee function in patients with KOA, and the soft tissue around the knee joint should also be an important reference factor in KOA treatment.

Metabolomic Profiling in Combination with Data Association Analysis Provide Insights about Potential Metabolic Regulation Networks among Non-Volatile and Volatile Metabolites in Camellia sinensis cv Baijiguan.

The non-volatile and volatile metabolites in tea confer the taste and odor characteristics of tea fusion, as well as shape the chemical base for tea quality. To date, it remains largely elusive whether there are metabolic crosstalks among non-volatile metabolites and volatile metabolites in the tea tree. Here, we generated an F1 half-sib population by using an albino cultivar of Camellia sinensis cv Baijiguan as the maternal parent, and then we quantified the non-volatile metabolites and volatile metabolites from individual half-sibs. We found that the EGC and EGCG contents of the albino half-sibs were significantly lower than those of the green half-sibs, while no significant differences were observed in total amino acids, caffeine, and other catechin types between these two groups. The phenylpropanoid pathway and the MEP pathway are the dominant routes for volatile synthesis in fresh tea leaves, followed by the MVA pathway and the fatty acid-derivative pathway. The total volatile contents derived from individual pathways showed large variations among half-sibs, there were no significant differences between the albino half-sibs and the green half-sibs. We performed a comprehensive correlation analysis, including correlations among non-volatile metabolites, between volatile synthesis pathways and non-volatile metabolites, and among the volatiles derived from same synthesis pathway, and we identified several significant positive or negative correlations. Our data suggest that the synthesis of non-volatile and volatile metabolites is potentially connected through shared intermediates; feedback inhibition, activation, or competition for common intermediates among branched pathways may co-exist; and cross-pathway activation or inhibition, as well as metabolome channeling, were also implicated. These multiple metabolic regulation modes could provide metabolic plasticity to direct carbon flux and lead to diverse metabolome among Baijiguan half-sibs. This study provides an essential knowledge base for rational tea germplasm improvements.

Functional identification of purine permeases reveals their roles in caffeine transport in tea plants (Camellia sinensis).

Caffeine is a characteristic secondary metabolite in tea plants. It confers tea beverage with unique flavor and excitation effect on human body. The pathway of caffeine biosynthesis has been generally established, but the mechanism of caffeine transport remains unclear. Here, eight members of purine permeases (PUPs) were identified in tea plants. They had diverse expression patterns in different tissues, suggesting their broad roles in caffeine metabolism. In this study, F1 strains of "Longjing43" ♂ × "Baihaozao" ♀ and different tea cultivars were used as materials to explore the correlation between caffeine content and gene expression. The heterologous expression systems of yeast and Arabidopsis were applied to explore the function of CsPUPs. Correlation analysis showed that the expressions of CsPUP1, CsPUP3.1, and CsPUP10.1 were significantly negatively correlated with caffeine content in tea leaves of eight strains and six cultivars. Furthermore, subcellular localization revealed that the three CsPUPs were not only located in plasma membrane but also widely distributed as circular organelles in cells. Functional complementation assays in yeast showed that the three CsPUPs could partly or completely rescue the defective function of fcy2 mutant in caffeine transport. Among them, transgenic yeast of CsPUP10.1 exhibited the strongest transport capacity for caffeine. Consistent phenotypes and functions were further identified in the CsPUP10.1-over-expression Arabidopsis lines. Taken together, it suggested that CsPUPs were involved in caffeine transport in tea plants. Potential roles of CsPUPs in the intracellular transport of caffeine among different subcellular organelles were proposed. This study provides a theoretical basis for further research on the PUP genes and new insights for caffeine metabolism in tea plants.

The GC-TOF/MS-based Metabolomic analysis reveals altered metabolic profiles in nitrogen-deficient leaves and roots of tea plants (Camellia sinensis).

BACKGROUND: Nitrogen (N) fertilizer is commonly considered as one of the most important limiting factors in the agricultural production. As a result, a large amount of N fertilizer is used to improve the yield in modern tea production. Unfortunately, the large amount of N fertilizer input has led to increased plant nitrogen-tolerance and decreased amplitude of yield improvement, which results in significant N loss, energy waste and environment pollution. However, the effects of N-deficiency on the metabolic profiles of tea leaves and roots are not well understood. RESULTS: In this study, seedlings of Camellia sinensis (L.) O. Kuntze Chunlv 2 were treated with 3 mM NH4NO3 (Control) or without NH4NO3 (N-deficiency) for 4 months by sandy culture. The results suggested that N-deficiency induced tea leaf chlorosis, impaired biomass accumulation, decreased the leaf chlorophyll content and N absorption when they were compared to the Control samples. The untargeted metabolomics based on GC-TOF/MS approach revealed a discrimination of the metabolic profiles between N-deficient tea leaves and roots. The identification and classification of the altered metabolites indicated that N deficiency upregulated the relative abundances of most phenylpropanoids and organic acids, while downregulated the relative abundances of most amino acids in tea leaves. Differentially, N-deficiency induced the accumulation of most carbohydrates, organic acids and amino acids in tea roots. The potential biomarkers screened in N-deficient leaves compared to Control implied that N deficiency might reduce the tea quality. Unlike the N-deficient leaves, the potential biomarkers in N-deficient roots indicated an improved stress response might occur in tea roots. CONCLUSIONS: The results demonstrated N deficiency had different effects on the primary and secondary metabolism in tea leaves and roots. The findings of this study will facilitate a comprehensive understanding of the N-deficient tea plants and provide a valuable reference for the optimized N nutrient management and the sustainable development in the tea plantations.

Leaf Cuticular Transpiration Barrier Organization in Tea Tree Under Normal Growth Conditions.

The cuticle plays a major role in restricting nonstomatal water transpiration in plants. There is therefore a long-standing interest to understand the structure and function of the plant cuticle. Although many efforts have been devoted, it remains controversial to what degree the various cuticular parameters contribute to the water transpiration barrier. In this study, eight tea germplasms were grown under normal conditions; cuticle thickness, wax coverage, and compositions were analyzed from the epicuticular waxes and the intracuticular waxes of both leaf surfaces. The cuticular transpiration rates were measured from the individual leaf surface as well as the intracuticular wax layer. Epicuticular wax resistances were also calculated from both leaf surfaces. The correlation analysis between the cuticular transpiration rates (or resistances) and various cuticle parameters was conducted. We found that the abaxial cuticular transpiration rates accounted for 64-78% of total cuticular transpiration and were the dominant factor in the variations for the total cuticular transpiration. On the adaxial surface, the major cuticular transpiration barrier was located on the intracuticular waxes; however, on the abaxial surface, the major cuticular transpiration barrier was located on the epicuticular waxes. Cuticle thickness was not a factor affecting cuticular transpiration. However, the abaxial epicuticular wax coverage was found to be significantly and positively correlated with the abaxial epicuticular resistance. Correlation analysis suggested that the very-long-chain aliphatic compounds and glycol esters play major roles in the cuticular transpiration barrier in tea trees grown under normal conditions. Our results provided novel insights about the complex structure-functional relationships in the tea cuticle.

Improving Stability of Cesium Lead Iodide Perovskite Nanocrystals by Solution Surface Treatments.

Cesium lead halide perovskite nanocrystals have a narrow emission peak tunable in the visible wavelength range with a high quantum yield. They hold great potential for optoelectronic applications such as light-emitting diodes or electronic displays. However, cesium lead iodide (CsPbI3) is not stable under ambient conditions, limiting its applications. Here, we use a solution surface treatment approach to improve the photostability of CsPbI3 suspensions in toluene. When a CsPbBr3 precursor is used via the method of heterogeneous surface treatment, the photoluminescence (PL) intensity is enhanced but the PL only lasts 2 days. In contrast, when a CsPbI3 precursor is used via the method of homogeneous surface treatment, not only the PL intensity of CsPbI3 suspensions is enhanced but also the stability with the PL lasts for 11 days. It is likely that a better protection on the core CsPbI3 by itself can be achieved because of better matching of the material structure and surface chemistry.

Metabolite Profiling and Transcriptome Analysis Revealed the Chemical Contributions of Tea Trichomes to Tea Flavors and Tea Plant Defenses.

Tea trichomes contain special flavor-determining metabolites; however, little is known about how and why tea trichomes produce them. Integrated metabolite and transcriptome profiling on tea trichomes in comparison with that on leaves showed that trichomes contribute to tea plant defense and tea flavor and nutritional quality. These unicellular, nonglandular, and unbranched tea trichomes produce a wide array of tea characteristic metabolites, such as UV-protective flavonoids, insect-toxic caffeine, herbivore-defensive volatiles, and theanine, as evidenced by the expression of whole sets of genes involved in different metabolic pathways. Both dry and fresh trichomes contain several volatiles and flavonols that were not found or at much low levels in trichome-removed leaves, including benzoic acid derivatives, lipid oxidation derivatives, and monoterpene derivatives. Trichomes also specifically expressed many disease signaling genes and various antiherbivore or antiabiotic peptides. Trichomes are one of the domestication traits in tea plants. Tea trichomes contribute to tea plant defenses and tea flavors.

A Proposed Method for Simultaneous Measurement of Cuticular Transpiration From Different Leaf Surfaces in Camellia sinensis.

The plant cuticle is the major barrier that limits unrestricted water loss and hence plays a critical role in plant drought tolerance. Due to the presence of stomata on the leaf abaxial surface, it is technically challenging to measure abaxial cuticular transpiration. Most of the existing reports were only focused on leaf astomatous adaxial surface, and few data are available regarding abaxial cuticular transpiration. Developing a method that can measure cuticular transpiration from both leaf surfaces simultaneously will improve our understanding about leaf transpiration barrier organization. Here, we developed a new method that enabled the simultaneous measurement of cuticular transpiration rates from the adaxial and abaxial surfaces. The proposed method combined multi-step leaf pretreatments including water equilibration under dark and ABA treatment to close stomata, as well as gum arabic or vaseline application to remove or seal the epicuticular wax layer. Mathematical formulas were established and used to calculate the transpiration rates of individual leaf surfaces from observed experimental data. This method facilitates the simultaneous quantification of cuticular transpiration from adaxial and abaxial leaf surfaces. By applying this method, we demonstrated that the adaxial intracuticular waxes and the abaxial epicuticular waxes constitute the major transpiration barriers in Camellia sinensis. Wax analysis indicated that adaxial intracuticular waxes had higher coverage of very long chain fatty acids, 1-alkanol esters, and glycols, which may be attributed to its higher transpiration barrier than that of the abaxial intracuticular waxes.

Drought stress modify cuticle of tender tea leaf and mature leaf for transpiration barrier enhancement through common and distinct modes.

Cuticle is the major transpiration barrier that restricts non-stomatal water loss and is closely associated with plant drought tolerance. Although multiple efforts have been made, it remains controversial what factors shape up the cuticular transpiration barrier. Previously, we found that the cuticle from the tender tea leaf was mainly constituted by very-long-chain-fatty-acids and their derivatives while alicyclic compounds dominate the mature tea leaf cuticle. The presence of two contrasting cuticle within same branch offered a unique system to investigate this question. In this study, tea seedlings were subjected to water deprivation treatment, cuticle structures and wax compositions from the tender leaf and the mature leaf were extensively measured and compared. We found that cuticle wax coverage, thickness, and osmiophilicity were commonly increased from both leaves. New waxes species were specifically induced by drought; the composition of existing waxes was remodeled; the chain length distributions of alkanes, esters, glycols, and terpenoids were altered in complex manners. Drought treatment significantly reduced leaf water loss rates. Wax biosynthesis-related gene expression analysis revealed dynamic expression patterns dependent on leaf maturity and the severity of drought. These data suggested that drought stress-induced structural and compositional cuticular modifications improve cuticle water barrier property. In addition, we demonstrated that cuticle from the tender leaf and the mature leaf were modified through both common and distinct modes.

Flexible inorganic CsPbI3 perovskite nanocrystal-PMMA composite films with enhanced stability in air and water for white light-emitting diodes.

Perovskite nanocrystals are a new type of fluorescent material with the advantages of facile preparation process, bright tunable color with high quantum yield. They are ideal candidates for optoelectronic devices such as light-emitting diode (LED) and display. However, for practical applications of iodine-based perovskite nanocrystals, the photostability remains a great challenge because of their sensitivity to environmental factors such as oxygen, humidity etc. In this paper, we improve the photostability of CsPbI3 by introducing the polymethyl methacrylate (PMMA) as a matrix to form flexible perovskite/PMMA composite films. The composite films maintain good photoluminescence quantum yield for 25 d in air and 4 d in water. Furthermore, these films are flexible and can sustain multiple bending and folding while maintaining their photoluminescence properties. This photostability against mechanical deformation allows for the development of flexible devices. As an example, flexible white light-emitting diodes (WLED) were produced with chromaticity coordination (0.31, 0.32), color temperature 6735 K and good stability over time.

Plasticity of the Cuticular Transpiration Barrier in Response to Water Shortage and Resupply in Camellia sinensis: A Role of Cuticular Waxes.

The cuticle is regarded as a non-living tissue; it remains unknown whether the cuticle could be reversibly modified and what are the potential mechanisms. In this study, three tea germplasms (Wuniuzao, 0202-10, and 0306A) were subjected to water deprivation followed by rehydration. The epicuticular waxes and intracuticular waxes from both leaf surfaces were quantified from the mature 5th leaf. Cuticular transpiration rates were then measured from leaf drying curves, and the correlations between cuticular transpiration rates and cuticular wax coverage were analyzed. We found that the cuticular transpiration barriers were reinforced by drought and reversed by rehydration treatment; the initial weak cuticular transpiration barriers were preferentially reinforced by drought stress, while the original major cuticular transpiration barriers were either strengthened or unaltered. Correlation analysis suggests that cuticle modifications could be realized by selective deposition of specific wax compounds into individual cuticular compartments through multiple mechanisms, including in vivo wax synthesis or transport, dynamic phase separation between epicuticular waxes and the intracuticular waxes, in vitro polymerization, and retro transportation into epidermal cell wall or protoplast for further transformation. Our data suggest that modifications of a limited set of specific wax components from individual cuticular compartments are sufficient to alter cuticular transpiration barrier properties.

Conserved MicroRNA Act Boldly During Sprout Development and Quality Formation in Pingyang Tezaocha (Camellia sinensis).

Tea tree [Camellia sinensis (L.) O. Kuntze] is an important leaf (sometimes tender stem)-using commercial plant with many medicinal uses. The development of newly sprouts would directly affect the yield and quality of tea product, especially significant for Pingyang Tezaocha (PYTZ) which takes up a large percent in the early spring tea market. MicroRNA (miRNA), particularly the conserved miRNAs, often position in the center of subtle and complex gene regulatory systems, precisely control the biological processes together with other factors in a spatio-temporal pattern. Here, quality-determined metabolites catechins, theanine and caffeine in PYTZ sprouts including buds (sBud), different development stages of leaves (sL1, sL2) and stems (sS1, sS2) were quantified. A total of 15 miRNA libraries of the same tissue with three repetitions for each were constructed to explore vital miRNAs during the biological processes of development and quality formation. We analyzed the whole miRNA profiles during the sprout development and defined conserved miRNA families in the tea plant. The differentially expressed miRNAs related to the expression profiles buds, leaves, and stems development stages were described. Twenty one miRNAs and eight miRNA-TF pairs that most likely to participate in regulating development, and at least two miRNA-TF-metabolite triplets that participate in both development and quality formation had been filtered. Our results indicated that conserved miRNA act boldly during important biological processes, they are (i) more likely to be linked with morphological function in primary metabolism during sprout development, and (ii) hold an important position in secondary metabolism during quality formation in tea plant, also (iii) coordinate with transcription factors in forming networks of complex multicellular organism regulation.