Investigation of heat stress responses and adaptation mechanisms by integrative metabolome and transcriptome analysis in tea plants (Camellia sinensis).

Extreme high temperature has deleterious impact on the yield and quality of tea production, which has aroused the attention of growers and breeders. However, the mechanisms by which tea plant varieties respond to extreme environmental heat is not clear. In this study, we analyzed physiological indices, metabolites and transcriptome differences in three different heat-tolerant tea plant F1 hybrid progenies. Results showed that the antioxidant enzyme activity, proline, and malondialdehyde were significantly decreased in heat-sensitive 'FWS' variety, and the accumulation of reactive oxygen molecules such as H2O2 and O2- was remarkably increased during heat stress. Metabolomic analysis was used to investigate the metabolite accumulation pattern of different varieties in response to heat stress. The result showed that a total of 810 metabolites were identified and more than 300 metabolites were differentially accumulated. Transcriptional profiling of three tea varieties found that such genes encoding proteins with chaperon domains were preferentially expressed in heat-tolerant varieties under heat stress, including universal stress protein (USP32, USP-like), chaperonin-like protein 2 (CLP2), small heat shock protein (HSP18.1), and late embryogenesis abundant protein (LEA5). Combining metabolomic with transcriptomic analyses discovered that the flavonoids biosynthesis pathway was affected by heat stress and most flavonols were up-regulated in heat-tolerant varieties, which owe to the preferential expression of key FLS genes controlling flavonol biosynthesis. Take together, molecular chaperons, or chaperon-like proteins, flavonols accumulation collaboratively contributed to the heat stress adaptation in tea plant. The present study elucidated the differences in metabolite accumulation and gene expression patterns among three different heat-tolerant tea varieties under extreme ambient high temperatures, which helps to reveal the regulatory mechanisms of tea plant adaptation to heat stress, and provides a reference for the breeding of heat-tolerant tea plant varieties.

Soil Microbial Community Characteristics and Their Effect on Tea Quality under Different Fertilization Treatments in Two Tea Plantations.

Fertilization is an essential aspect of tea plantation management that supports a sustainable tea production and drastically influences soil microbial communities. However, few research studies have focused on the differences of microbial communities and the variation in tea quality in response to different fertilization treatments. In this work, the soil fertility, tea quality, and soil microbial communities were investigated in two domestic tea plantations following the application of chemical and organic fertilizers. We determined the content of mineral elements in the soil, including nitrogen, phosphorus, and potassium, and found that the supplementation of chemical fertilizer directly increased the content of mineral elements. However, the application of organic fertilizer significantly improved the accumulation of tea polyphenols and reduced the content of caffeine. Furthermore, amplicon sequencing results showed that the different ways of applying fertilizer have limited effect on the alpha diversity of the microbial community in the soil while the beta diversity was remarkably influenced. This work also suggests that the bacterial community structure and abundance were also relatively constant while the fungal community structure and abundance were dramatically influenced; for example, Chaetomiaceae at the family level, Hypocreaceae at the order level, Trichoderma at the genus level, and Fusarium oxysporum at the species level were predominantly enriched in the tea plantation applying organic fertilizer. Moreover, the bacterial and fungal biomarkers were also analyzed and it was found that Proteobacteria and Gammaproteobacteria (bacteria) and Tremellomycetes (fungi) were potentially characterized as biomarkers in the plantation under organic fertilization. These results provide a valuable basis for the application of organic fertilizer to improve the soil of tea plantations in the future.

Impacts of p-GaN layer thickness on the photoelectric and thermal performance of AlGaN-based deep-UV LEDs.

The effects of different p-GaN layer thickness on the photoelectric and thermal properties of AlGaN-based deep-ultraviolet light-emitting diodes (DUV-LEDs) were investigated. The results revealed that appropriate thinning of the p-GaN layer enhances the photoelectric performance and thermal stability of DUV-LEDs, reducing current crowding effects that affect the external quantum efficiency and chip heat dissipation. The ABC + f(n) model was used to analyse the EQE, which helped in identifying the different physical mechanisms for DUV-LEDs with different p-GaN layer thickness. Moreover, the finite difference time domain simulation results revealed that the light-extraction efficiency of the DUV-LEDs exhibits a trend similar to that of damped vibration as the thickness of the p-GaN layer increases. The AlGaN-based DUV-LED with a p-GaN layer thickness of 20 nm exhibited the best photoelectric characteristics and thermal stability.

Effect of Leaf Grade on Taste and Aroma of Shaken Hunan Black Tea.

Shaken Hunan black tea is an innovative Hunan black tea processed by adding shaking to the traditional Hunan black tea. The quality of shaken black tea is influenced by leaf grades of different maturity. In this study, the taste and aroma quality of shaken Hunan black tea processed with different grades were analyzed by sensory evaluation (SP, HPLC, and HS-SPME/GC-MS). The results showed that shaken Hunan black tea processed with one bud and two leaves has the best quality, which has a sweet, mellow, and slightly floral taste, as well as a floral, honey, and sweet aroma. Moreover, caffeine and EGCG were identified as the most important bitter and astringent substances in shaken Hunan black. Combined with the analysis of GC-MS and OAV analysis, geraniol, jasmone, ß-myrcene, citral, and trans-ß-ocimene might be the most important components that affect the sweet aroma, while methyl jasmonate, indole, and nerolidol were the key components that affect the floral aroma of shaken Hunan black tea. This study lays a foundation for this study of the taste and aroma characteristics of shaken Hunan black tea and guides enterprises to improve shaken black tea processing technology.

Metabolomic and transcriptomic analyses reveal a MYB gene, CsAN1, involved in anthocyanins accumulation separation in F1 between 'Zijuan' (Camellia sinensis var. assamica) and 'Fudingdabaicha' (C. sinensis var. sinensis) tea plants.

'Zijuan' (Camellia sinensis var. assamica), a somatic mutant with purple foliage and stem selected from the Yunnan Daye cultivar, has been well developed owing to abnormal pattern of anthocyanin accumulation. However, the genetic basis for the specific accumulation of phloem glycosides is not clear. Tea plants are self-incompatible, so parents with large differences in foliage color were used for crosses to investigate the genetic mechanism of anthocyanins. In this study, 'Zijuan' and green foliage cultivar 'Fudingdabaicha' (C. sinensis var. sinensis) were used as female and male parents, respectively, to generated F1 hybrid progenies with various anthocyanin contents. In order to decipher the genetic rules of anthocyanins accumulation, we performed widely targeted metabolic and transcriptomic profiling. The results showed that cyanidin-3-O-galactoside, delphinidin-3-O-galactoside and petunidin-3-O-galactoside were the major types of anthocyanins and factors directly led to the color variation between parents and F1 plants. Transcriptomic analyses suggested the significant up-regulation of anthocyanidin synthase gene (CsANS1) and CsAN1, a MYB family gene positively regulated the expression of CsANS1, in anthocyanin-rich tea plants. Furthermore, the deletion mutation of CsAN1 was found by cloning and alignment in anthocyanin-lacking cultivars. Taken together, the function deficiency of CsAN1 is predominantly responsible for the inability of anthocyanins accumulation, and this trait is heritable in progenies through hybridization. The present study elucidated the molecular basis of leaf purple trait formation in 'zijuan' and 'Fudingdabaicha' and their F1 plants, which helps to elucidate the genetic mechanism of leaf anthocyanin accumulation regulation in tea plants, and the results provide a research reference for the selection and breeding of high anthocyanin type tea varieties.

Transcriptome and metabolite analysis identifies nitrogen utilization genes in tea plant (Camellia sinensis).

Applied nitrogen (N) fertilizer significantly increases the leaf yield. However, most N is not utilized by the plant, negatively impacting the environment. To date, little is known regarding N utilization genes and mechanisms in the leaf production. To understand this, we investigated transcriptomes using RNA-seq and amino acid levels with N treatment in tea (Camellia sinensis), the most popular beverage crop. We identified 196 and 29 common differentially expressed genes in roots and leaves, respectively, in response to ammonium in two tea varieties. Among those genes, AMT, NRT and AQP for N uptake and GOGAT and GS for N assimilation were the key genes, validated by RT-qPCR, which expressed in a network manner with tissue specificity. Importantly, only AQP and three novel DEGs associated with stress, manganese binding, and gibberellin-regulated transcription factor were common in N responses across all tissues and varieties. A hypothesized gene regulatory network for N was proposed. A strong statistical correlation between key genes' expression and amino acid content was revealed. The key genes and regulatory network improve our understanding of the molecular mechanism of N usage and offer gene targets for plant improvement.

Efficient removal of lead from solution by celery-derived biochars rich in alkaline minerals.

Biochars were produced from celery biomass by slow pyrolysis at 350 and 500°C, and featured by high content of alkaline minerals namely salts of alkali and alkaline earth metals. The biochars' efficiency on removing Pb2+ from solution was investigated, and two biochars derived from celery stalk (StC350 and StC500) showed higher Pb2+ sorption capacity (288 and 304mg/g) than most biochars reported previously. The sorption mechanisms involving precipitation, cation exchange and surface complexation are related to three biochar fractions namely water-soluble matter, acid-soluble substances and insoluble organic carbon. The relative contributions of water-soluble matter and acid-soluble substances to the total Pb2+ removal were 59.8% and 36.6% for the StC350 biochar, and 62.8% and 34.9% for the StC500 biochar, respectively. The results indicate that biochars derived from vegetable wastes are potential candidates for efficient sorption of heavy metals.

Relationship between biochars' porosity and adsorption of three neutral herbicides from water.

The porous biochars have exhibited good adsorption to many organic pollutants, but the relationship between biochars' porosity and their adsorption capacity is not clear at the moment. In this work, six biochars were produced from different feedstocks and under different pyrolysis conditions, and used for adsorption of three neutral herbicides from water. The results demonstrated that the adsorption capacity was dominated by the mesopore (1.7-50 nm) area of biochars, instead of their total surface area, according to the analysis of surface area-normalized adsorption data with both Langmuir model and a mixed adsorption and partition model. The results implied the inaccessibility of most micropores in biochars to the organic molecules with nano-scale molecular dimension, and alkalis in feedstock and an oxygen-containing atmosphere in heat treatment for producing biochars would favor the development of mesopores.

Stabilization of Pb(II) accumulated in biomass through phosphate-pretreated pyrolysis at low temperatures.

The remediation of heavy metal-contaminated soil and water using plant biomass is considered to be a green technological approach, although the harmless disposal of biomass accumulated with heavy metals remains a challenge. A potential solution to this problem explored in this work involves combining phosphate pretreatment with pyrolysis. Pb(II) was accumulated in celery biomass with superior sorption capacity and also in ordinary wood biomass through biosorption. The Pb(II)-impregnated biomass was then pretreated with phosphoric acid or calcium dihydrogen phosphate (CaP) and pyrolyzed at 350 or 450°C. Pb(II) from biomass was in turn almost totally retained in chars, and the percentage of DTPA-extractable Pb(II) was reduced to less than 5% of total Pb(II) in chars through CaP pretreatment. Pb(II) stabilization was further confirmed through a sequential extraction test, which showed that more than 95% of Pb(II) was converted into stable species composed mainly of lead phosphates according to X-ray diffraction (XRD) and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) analyses. Overall, phosphate-pretreated pyrolysis can stabilize both Pb(II) and degradable biomass, so as to control efficiently the hazards of heavy metal-contaminated biomass.

Influence of Al-oxide on pesticide sorption to woody biochars with different surface areas.

Biochars' properties will change after application in soil due to the interactions with soil constituents, which would then impact the performance of biochars as soil amendment. For a better understanding on these interactions, two woody biochars of different surface areas (SA) were physically treated with aluminum oxide (Al-oxide) to investigate its potential influence on biochars' sorption property. Both the micropore area and mesopore (17∼500 Å in diameter) area of the low-SA biochar were enhanced by at least 1.5 times after treatment with Al-oxide, whereas the same treatment did not change the surface characteristics of the high-SA biochar due partly to its well-developed porosity. The enhanced sorption of the pesticide isoproturon to the Al-oxide-treated low-SA biochar was observed and is positively related to the increased mesopore area. The desorption hysteresis of pesticide from the low-SA biochar was strengthened because of more pesticide molecules entrapped in the expanded pores by Al-oxide. However, no obvious change of pesticide sorption to the high-SA biochar after Al-oxide treatment was observed, corresponding to its unchanged porosity. The results suggest that the influence of Al-oxide on the biochars' sorption property is dependent on their porosity. This study will provide valuable information on the use of biochars for reducing the bioavailability of pesticides.

Role of Alumina and Montmorillonite in Changing the Sorption of Herbicides to Biochars.

The influence of biochars on the fate of herbicides in soil depends mostly on environmental factors among which the role of soil minerals is not clear. Two wood-derived biochars produced at 400 °C (BC400) and 600 °C (BC600) were treated with alumina and montmorillonite to investigate their interaction with biochars and the influence of herbicide sorption. Both minerals exhibited a pore-expanding effect that was likely relative to the removal of authigenic organic matter away from the biochars' surface. Alumina brought more remarkable pore expansion by doubling the surface area of the BC400 biochar and the mesopore area of the BC600 biochar. Consequently, more adsorption sites were accessible for herbicide molecules, which resulted in higher sorption of herbicides (acetochlor and metribuzin) to the mineral-treated biochars than to the untreated biochars. The results are useful for understanding the change of surface and sorption properties of biochars with soil applications.

[Pathologic observation on animal model of silicosis].

OBJECTIVE: To explore the pathological changes of pulmonary fibrosis induced by SiO2 in rats and pigs. METHODS: The silicosis models in rats and pigs were established by non-exposure method. The pathologic changes in lung tissues of rats and pigs were observed with HE staining under a light microscopy and under a transmission electron microscopy (TEM), the expression of cytokines was detected by immunohistochemistry. RESULTS: (1) The main pathologic changes of silicosis models in rats and pigs included: in 7 ∼ 15 days after treatment, silica dusts, dust cells, a lot of macrophages, lung epithelial cells, a few neutrophils, macrophage alveolar inflammation and nodules of stage I were found in alveolar space; in 30 ∼ 90 days after treatment, many nodules of stage I-III or IV with lymphocytes infiltration were observed in respiratory bronchioles, alveoli, interlobular septa, the subpleural and around blood vessels and bronchi. (2) The expression levels of CK protein, SP-A protein, CD68, b-FGF, TNF-α, IL-6, TGF-ß1, NFKappa/P50, Kappa/P65 and VEGF reduced with exposure time, but still were higher than those of the control. (3) The shed alveolar type I cells, proliferation of alveolar type II cells or macrophages and activated cellular function induced by silica were observed under TEM. CONCLUSION: The development of pulmonary fibrosis in silicosis models corresponded with the process from macrophages alveolar inflammation to pulmonary fibrosis.

[Study on the interactions between rhizoma coptidis and radix glycyrrhiza].

Ancient prescription rhiaoma coptidis powder is a kind of traditional Chinese medicine compounds (TCMC) which is composed of rhizoma coptidis (RC) and radix glycyrrhiza (RG). In the present investigation, the compositions in solutions and precipitates of single decocted RC and RG, and decocted RC-RG mixture were studied by FTIR spectroscopy, HPLC technique and TOF-MS method. The components of decocted RC-RG mixture are different from those of the addition of RC and RG, suggesting that the interactions between RC and RG occurred. The results of FTIR spectroscopic characterization, and HPLC and TOF-MS measurements demonstrated that in both solutions and precipitates some new chemical compounds formed, while some components in the original single decocted RC and RG were restrained in the mixed system, indicating that RG plays an important role in this TCMC-rhizoma coptidis powder.

[Spectroscopic studies on different chemical composition between the shell and core of Radix Notoginseng].

Notoginseng (Sanqi) is one of the most important components of famous Chinese recipe (Yunan Baiyao) and possesses a wide variety of applications in clinical practice. It has been found that Sanqi of different size exhibits different curative effects. Such a phenomenon may be attributed to that the chemical constituent from shell region is different from that of core region. To prove the above-mentioned hypothesis, Ultraviolet-Visible (UV-Vis), FTIR, fluorescence spectroscopy, together with high performance liquid chromatography (HPLC) and electrospray ionization mass spectroscopy (ESI-MS) were utilized to study the variation of chemical compositions from shell and core regions of Sanqi. The results demonstrate that the chemical compositions of Sanqi from shell and core regions are different. In summary, differences in chemical composition between Sanqi shell and core were manifested from versatile aspects. Such differences shed a light on the different curative effects of Sanqi.