RESUMO
Tea plantations in Karst regions suffer from the serious effects of frequent temporary karst droughts, leading to a decline in tea production and quality in the region. The close relationship between growth and electrical parameters of plants, including physiological capacitance, resistance and impedance, can be used to accurately monitor their plant water status online, quickly, accurately, timely and nondestructively. In this study, three tea tree cultivars of Zhonghuang No.2 (ZH), Wuniuzao (WNZ), and Longjing 43 (LJ) with different levels of drought resistance were selected as experimental materials, and experiments were carried out under controlled conditions according to control (soil water content of 40-45%, D0), (keeping D0 no watering to 5 days, D5), (keeping D0 no watering to 10 days, D10), (the first day after D10 is rehydrated to D0 is regarded as R1) and (the fifth day after D10 rehydration to D0 is regarded as R5), to determine intracellular water metabolism and nutrient translocation characteristics based on intrinsic electrical parameters. The photosynthetic characteristics and chlorophyll fluorescence parameters were also determined to investigate the response of water metabolism to simulated karst drought in the three tea tree cultivars. The results indicated that the water metabolism patterns responded to environmental water changes with a medium water-holding capacity, medium water transport rate, and low water-use efficiency, and the nutrient patterns in those tea tree varieties demonstrated with a high nutrient flux per unit area, low nutrient transfer rate, and high nutrient transport capacity. After rehydration, only the electrical characteristics of WNZ returned to the D0 levels, but the net photosynthetic rate of all varieties returned to or even exceeded the D0 levels. The chlorophyll fluorescence parameters could not be used to characterize the recoverability of metabolism in tea trees. The electrical characteristics quickly reflected the response of the water metabolism in plants to environmental changes, and the fusion of electrical characteristics and photosynthetic characteristics was able to more quickly, accurately, and comprehensively reflect the response of water metabolism to temporary karst drought.
Assuntos
Camellia sinensis , Secas , Fotossíntese , Água , Fotossíntese/fisiologia , Camellia sinensis/fisiologia , Camellia sinensis/metabolismo , Água/metabolismo , Clorofila/metabolismoRESUMO
Zikui (Camellia sinensis cv. Zikui) is a recently discovered cultivar of local purple tea in Guizhou, China. It is a purple leaf bud mutation material of Meitan Taicha (Camellia sinensis cv. 'Meitan-taicha') 'N61' strain, which is an important local germplasm resource in Guizhou. It is also a model plant for the study of anthocyanins, but the limited germplasm resources and the limitation of traditional reproduction hinder its application. Here, an efficient regeneration system is established by using hypocotyl as explants for the first time. Different plant growth regulators (PGRs) are evaluated during different regeneration processes including callus and root induction. According to our findings, using the optimal disinfection conditions, the seed embryo contamination rate is 17.58%. Additionally, the mortality rate is 9.69%, while the survival rate is measured as 72.73%. Moreover, the highest germination rate of 93.64% is observed under MS + 2.40 mg/L GA3 medium conditions. The optimal callus induction rate is 95.19%, while the optimal adventitious bud differentiation rate is 20.74%, Medium with 1.6 mg/L IBA achieved 68.6% rooting of the adventitious shoots. The survival rate is more than 65% after 6 days growth in the cultivated matrix. In summary, our research aims to establish a regeneration system for Zikui tea plants and design a transformation system for tea plant tissue seedlings. This will enable transfer of the target gene and ultimately facilitate the cultivation of new tea varieties with unique characteristics.
Assuntos
Camellia sinensis , Hipocótilo , Reguladores de Crescimento de Plantas , Regeneração , Hipocótilo/crescimento & desenvolvimento , Camellia sinensis/crescimento & desenvolvimento , Camellia sinensis/fisiologia , Camellia sinensis/genética , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Raízes de Plantas/crescimento & desenvolvimento , Germinação , CháRESUMO
BACKGROUND: The tea plant (Camellia sinensis (L.) O. Kuntze) is one of the most economically important woody crops. Plastic greenhouse covering cultivation has been widely used in tea areas of northern China. Chlorophyll is not only the crucial pigment for green tea, but also plays an important role in the growth and development of tea plants. Currently, little is known about the effect of plastic greenhouse covering cultivation on chlorophyll in tea leaves. RESULTS: To investigate the effect of plastic greenhouse covering cultivation on chlorophyll in tea leaves, color difference values, chlorophyll contents, gene expression, enzyme activities and photosynthetic parameters were analyzed in our study. Sensory evaluation showed the color of appearance, liquor and infused leaves of greenhouse tea was greener than field tea. Color difference analysis for tea liquor revealed that the value of ∆L, ∆b and b/a of greenhouse tea was significantly higher than field tea. Significant increase in chlorophyll content, intracellular CO2, stomatal conductance, transpiration rate, and net photosynthetic rate was observed in greenhouse tea leaves. The gene expression and activities of chlorophyll-metabolism-related enzymes in tea leaves were also activated by greenhouse covering. CONCLUSION: The higher contents of chlorophyll a, chlorophyll b and total chlorophyll in greenhouse tea samples were primarily due to higher gene expression and activities of chlorophyll-metabolism-related enzymes especially, chlorophyll a synthetase (chlG), pheophorbide a oxygenase (PAO) and chlorophyllide a oxygenase (CAO) in tea leaves covered by greenhouse. In general, our results revealed the molecular basis of chlorophyll metabolism in tea leaves caused by plastic greenhouse covering cultivation, which had great significance in production of greenhouse tea.
Assuntos
Camellia sinensis , Clorofila , Folhas de Planta , Camellia sinensis/genética , Camellia sinensis/enzimologia , Camellia sinensis/crescimento & desenvolvimento , Camellia sinensis/fisiologia , Camellia sinensis/metabolismo , Clorofila/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/genética , Fotossíntese , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genéticaRESUMO
BACKGROUND: The circadian clock, also known as the circadian rhythm, is responsible for predicting daily and seasonal changes in the environment, and adjusting various physiological and developmental processes to the appropriate times during plant growth and development. The circadian clock controls the expression of the Lhcb gene, which encodes the chlorophyll a/b binding protein. However, the roles of the Lhcb gene in tea plant remain unclear. RESULTS: In this study, a total of 16 CsLhcb genes were identified based on the tea plant genome, which were distributed on 8 chromosomes of the tea plant. The promoter regions of CsLhcb genes have a variety of cis-acting elements including hormonal, abiotic stress responses and light response elements. The CsLhcb family genes are involved in the light response process in tea plant. The photosynthetic parameter of tea leaves showed rhythmic changes during the two photoperiod periods (48 h). Stomata are basically open during the day and closed at night. Real-time quantitative PCR results showed that most of the CsLhcb family genes were highly expressed during the day, but were less expressed at night. CONCLUSIONS: Results indicated that CsLhcb genes were involved in the circadian clock process of tea plant, it also provided potential references for further understanding of the function of CsLhcb gene family in tea plant.
Assuntos
Camellia sinensis , Ritmo Circadiano , Fotossíntese , Fotossíntese/genética , Camellia sinensis/genética , Camellia sinensis/fisiologia , Ritmo Circadiano/genética , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Genes de Plantas , Família Multigênica , Proteínas de Ligação à Clorofila/genética , Proteínas de Ligação à Clorofila/metabolismo , FotoperíodoRESUMO
Cultivating drought-tolerant tea varieties enhances both yield and quality of tea plants in northern China. However, the mechanisms underlying their drought tolerance remain largely unknown. Here we identified a key regulator called CsREV, which differentially regulates xylem patterns between leaves and stems, thereby conferring drought tolerance in tea plants. When drought occurs, upregulation of CsREV activates the CsVND7a-dependent xylem vessel differentiation. However, when drought persists, the vessel differentiation is hindered as CsVND7a is downregulated by CsTCP4a. This, combined with the CsREV-promoted secondary-cell-wall thickness of xylem vessel, leads to the enhanced curling of leaves, a characteristic closely associated with plant drought tolerance. Notably, this inhibitory effect of CsTCP4a on CsVND7a expression is absent in stems, allowing stem xylem vessels to continuously differentiate. Overall, the CsREV-CsTCP4-CsVND7 module is differentially utilized to shape the xylem patterns in leaves and stems, potentially balancing water transportation and utilization to improve tea plant drought tolerance.
Assuntos
Secas , Regulação da Expressão Gênica de Plantas , Folhas de Planta , Proteínas de Plantas , Caules de Planta , Xilema , Xilema/metabolismo , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Caules de Planta/metabolismo , Caules de Planta/fisiologia , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Camellia sinensis/fisiologia , Camellia sinensis/genética , Camellia sinensis/metabolismo , Adaptação FisiológicaRESUMO
BACKGROUND: Caffeic acid O-methyltransferase (COMT) is a key enzyme that regulates melatonin synthesis and is involved in regulating the growth, development, and response to abiotic stress in plants. Tea plant is a popular beverage consumed worldwide, has been used for centuries for its medicinal properties, including its ability to reduce inflammation, improve digestion, and boost immune function. By analyzing genetic variation within the COMT family, while helping tea plants resist adversity, it is also possible to gain a deeper understanding of how different tea varieties produce and metabolize catechins, then be used to develop new tea cultivars with desired flavor profiles and health benefits. RESULTS: In this study, a total of 25 CsCOMT genes were identified based on the high-quality tea (Camellia sinensis) plant genome database. Phylogenetic tree analysis of CsCOMTs with COMTs from other species showed that COMTs divided into four subfamilies (Class I, II, III, IV), and CsCOMTs was distributed in Class I, Class II, Class III. CsCOMTs not only undergoes large-scale gene recombination in pairs internally in tea plant, but also shares 2 and 7 collinear genes with Arabidopsis thaliana and poplar (Populus trichocarpa), respectively. The promoter region of CsCOMTs was found to be rich in cis-acting elements associated with plant growth and stress response. By analyzing the previously transcriptome data, it was found that some members of CsCOMT family exhibited significant tissue-specific expression and differential expression under different stress treatments. Subsequently, we selected six CsCOMTs to further validated their expression levels in different tissues organ using qRT-PCR. In addition, we silenced the CsCOMT19 through virus-induced gene silencing (VIGS) method and found that CsCOMT19 positively regulates the synthesis of melatonin in tea plant. CONCLUSION: These results will contribute to the understanding the functions of CsCOMT gene family and provide valuable information for further research on the role of CsCOMT genes in regulating tea plant growth, development, and response to abiotic stress.
Assuntos
Camellia sinensis , Melatonina , Metiltransferases , Camellia sinensis/fisiologia , Melatonina/genética , Filogenia , Chá , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulação da Expressão Gênica de PlantasRESUMO
Glutathione S-transferases (GSTs) are ubiquitous enzymes involved in the regulation of plant growth, development, and stress responses. Unfortunately, the comprehensive identification of GSTs in tea plant has not been achieved. In this study, a total of 88 CsGSTs proteins were identified and divided into eight classes, among which the tau class was the largest. Chromosomal localization analysis revealed an uneven distribution of CsGSTs across the tea plant genome. Tandem duplication is the main force driving tea plant CsGSTs expansion. CsGSTs structures and conserved motifs were similar. The analysis of cis-regulatory elements in promoter regions showed that CsGSTs can response to multiple stresses, and that MYB may be involved in the transcriptional regulation of CsGST. RNA-Seq data revealed that the expression of most GSTUs was associated with various stresses, including pathogen and insect attack, cold spells, drought and salt stresses, nitrogen nutrition, bud dormancy, and morphological development, and the expression of these CsGSTs was obviously different in eight tissues. In addition, we proved that CsGSTU19, localized at the nucleus and cell membrane, was involved in tea plant defense against temperature stresses and Co. camelliae infection. These findings provide references for the further functional analysis of GSTs in the future.
Assuntos
Camellia sinensis , Glutationa Transferase , Proteínas de Plantas , Estresse Fisiológico , Camellia sinensis/genética , Camellia sinensis/fisiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Glutationa Transferase/genética , Filogenia , Proteínas de Plantas/genéticaRESUMO
BACKGROUND: Tea plants originated in southwestern China. Guizhou Plateau is an original center of tea plants, and is rich in germplasm resources. However, the genetic diversity, population structure and distribution characteristics of cultivated-type tea plants in the region are unknown. In this study, we explored the genetic diversity and geographical distribution of cultivated-type tea accessions in Guizhou Plateau. RESULTS: We used 112,072 high-quality genotyping-by-sequencing to analyze the genetic diversity, principal components, phylogeny, population structure, and linkage disequilibrium, and develop a core collection of 253 cultivated-type tea plant accessions from Guizhou Plateau. The results showed Genetic diversity of the cultivated-type tea accessions of the Pearl River Basin was significantly higher than that of the cultivated-type tea accessions of the Yangtze River Basin. Three inferred pure groups (CG-1, CG-2 and CG-3) and one inferred admixture group (CG-4), were identified by a population structure analysis, and verified by principal component and phylogenetic analyses. The highest genetic distance and differentiation coefficients were determined for CG-2 vs CG-3. The lower genetic distance and differentiation coefficients were determined for CG-4 vs CG-2 and CG-4 vs CG-3, respectively. We developed a core set and a primary set. The primary and core sets contained 77.0 and 33.6% of all individuals in the initial set, respectively. The primary set may serve as the primary population in genome-wide association studies, while the core collection may serve as the core population in multiple treatment setting studies. CONCLUSIONS: The present study demonstrated the genetic diversity and geographical distribution characteristics of cultivated-type tea plants in Guizhou Plateau. Significant differences in genetic diversity and evolutionary direction were detected between the ancient landraces of the Pearl River Basin and the those of the Yangtze River Basin. Major rivers and ancient hubs were largely responsible for the genetic exchange between the Pearl River Basin and the Yangtze River Basin ancient landraces as well as the formation of the ancient hubs evolutionary group. Genetic diversity, population structure and core collection elucidated by this study will facilitate further genetic studies, germplasm protection, and breeding of tea plants.
Assuntos
Camellia sinensis/genética , Camellia sinensis/fisiologia , Variação Genética , Agricultura , China , Demografia , Regulação da Expressão Gênica de Plantas , Genótipo , HumanosRESUMO
BACKGROUND: Catechins are crucial in determining the flavour and health benefits of tea, but it remains unclear that how the light intensity regulates catechins biosynthesis. Therefore, we cultivated tea plants in a phytotron to elucidate the response mechanism of catechins biosynthesis to light intensity changes. RESULTS: In the 250 µmol·m- 2·s- 1 treatment, the contents of epigallocatechin, epigallocatechin gallate and total catechins were increased by 98.94, 14.5 and 13.0% respectively, compared with those in the 550 µmol·m- 2·s- 1 treatment. Meanwhile, the photosynthetic capacity was enhanced in the 250 µmol·m- 2·s- 1 treatment, including the electron transport rate, net photosynthetic rate, transpiration rate and expression of related genes (such as CspsbA, CspsbB, CspsbC, CspsbD, CsPsbR and CsGLK1). In contrast, the extremely low or high light intensity decreased the catechins accumulation and photosynthetic capacity of the tea plants. The comprehensive analysis revealed that the response of catechins biosynthesis to the light intensity was mediated by the photosynthetic capacity of the tea plants. Appropriately high light upregulated the expression of genes related to photosynthetic capacity to improve the net photosynthetic rate (Pn), transpiration rate (Tr), and electron transfer rate (ETR), which enhanced the contents of substrates for non-esterified catechins biosynthesis (such as EGC). Meanwhile, these photosynthetic capacity-related genes and gallic acid (GA) biosynthesis-related genes (CsaroB, CsaroDE1, CsaroDE2 and CsaroDE3) co-regulated the response of GA accumulation to light intensity. Eventually, the epigallocatechin gallate content was enhanced by the increased contents of its precursors (EGC and GA) and the upregulation of the CsSCPL gene. CONCLUSIONS: In this study, the catechin content and photosynthetic capacity of tea plants increased under appropriately high light intensities (250 µmol·m- 2·s- 1 and 350 µmol·m- 2·s- 1) but decreased under extremely low or high light intensities (150 µmol·m- 2·s- 1 or 550 µmol·m- 2·s- 1). We found that the control of catechin accumulation by light intensity in tea plants is mediated by the plant photosynthetic capacity. The research provided useful information for improving catechins content and its light-intensity regulation mechanism in tea plant.
Assuntos
Camellia sinensis/efeitos da radiação , Catequina/análogos & derivados , Catequina/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Fotossíntese/efeitos da radiação , Proteínas de Plantas/metabolismo , Camellia sinensis/genética , Camellia sinensis/fisiologia , Catequina/efeitos da radiação , Luz , Proteínas de Plantas/genética , Plântula/genética , Plântula/fisiologia , Plântula/efeitos da radiação , Regulação para CimaRESUMO
Tea is one of the most consumed beverages worldwide, and trichome formation in tea plant leaves impairs their commercial value. In Arabidopsis thaliana leaves, trichome formation is negatively regulated by the CPC family genes, which encode R3-type MYB transcription factors. Here, we identified six CPC-like genes in a tea plant (Camellia sinensis var. sinensis) for the first time. Simulated three-dimensional structure of the MYB domains of all the six CPC-like proteins exhibited negative charge on the surface, as observed on that of the Arabidopsis CPC protein that does not bind to DNA, indicating their similarity with regard to molecular interaction. We further found that the six CPC-like genes were differentially expressed in different developmental stages of tea leaves, and four out of the six genes were upregulated in the youngest 1st leaves, which formed more trichomes than other older leaves. Although it does not establish a causal link, the correlation between differential expression of CPC-like genes and variable trichome formation suggests that the R3-type MYB transcription factors are potential precipitating factors in affecting the value of tea leaf.
Assuntos
Camellia sinensis/genética , Camellia sinensis/fisiologia , Genes de Plantas , Folhas de Planta/genética , Folhas de Planta/fisiologia , Proteínas Proto-Oncogênicas c-myb/genética , Tricomas/genética , Tricomas/fisiologia , Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Regulação da Expressão Gênica de Plantas , Variação Genética , Japão , Proteínas Proto-Oncogênicas c-myb/fisiologiaRESUMO
Low temperature is an important factor that affects the growth and reproduction of tea plants [Camellia sinensis (L.) Kuntze]. In this study, Yunwu Tribute Tea cutting seedlings [Camellia sinensis (L.) Kuntze var. niaowangensis Q.H. Chen] were subjected to different low-temperature treatments in Guizhou Province, China, and the changes in physiological indicators of the leaves were measured to investigate the physiological response and cold tolerance of this variety. Under cold stress, the peak of antioxidant enzyme activity appeared on the third day of treatment at 1°C, indicating that Yunwu Tribute Tea could improve the resistance to cold stress through an increase in enzyme activity within a low-temperature range. However, after 3 days treatment at 1°C, the tolerance of plant had been exceeded; the ability to resist cold stress disappeared, and enzyme activity decreased. When the temperature or duration of stress exceeded the maximum tolerance of the plant, the synthesis of soluble substances decreased in concert with their protective effects. Under cold conditions, Yunwu Tribute Tea could increase the production of abscisic acid growth inhibitors and reduce those of indoleacetic acid, gibberellin, and other growth promoting substances to manage cold stress by regulating the balance of growth regulators in the plant. Five differential genes were screened as candidate genes from the Yunwu Tribute Tea cold stress transcriptome (DW, 1°C) for fluorescence quantitative analysis. The results showed that the changes in levels of expression of these genes under continuous cold stress significantly positively correlated with the corresponding physiological indicators. Nevertheless, the levels of expression of the Yunwu Tribute Tea polyphenol oxidase (PPO) gene and the gibberellin 3ß-dioxygenase gene (G3O2) were reversely inhibited under cold stress. The result was consistent with the corresponding physiological indicators, and it provides a basis for the study of cold resistance mechanisms in tea plants.
Assuntos
Camellia sinensis/genética , Camellia sinensis/fisiologia , Resposta ao Choque Frio/genética , China , Temperatura Baixa , Expressão Gênica/genética , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica de Plantas/genética , Genes de Plantas/genética , Folhas de Planta/genética , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Plântula/genética , Plântula/crescimento & desenvolvimento , Estresse Fisiológico/genética , Chá/metabolismo , Temperatura , Transcriptoma/genéticaRESUMO
Unlike most crops, in which soil acidity severely limits productivity, tea (Camellia sinensis) actually prefers acid soils (pH 4.0-5.5). Specifically, tea is very tolerant of acidity-promoted aluminum (Al) toxicity, a major factor that limits the yield of most other crops, and it even requires Al for optimum growth. Understanding tea Al tolerance and Al-stimulatory mechanisms could therefore be fundamental for the future development of crops adapted to acid soils. Here, we summarize the Al-tolerance mechanisms of tea plants, propose possible mechanistic explanations for the stimulation of tea growth by Al based on recent research, and put forward ideas for future crop breeding for acid soils.
Assuntos
Alumínio/metabolismo , Camellia sinensis/fisiologia , Melhoramento Vegetal , Solo/química , Camellia sinensis/genéticaRESUMO
BACKGROUND: Branch angle is a pivotal component of tea plant architecture. Tea plant architecture not only affects tea quality and yield but also influences the efficiency of automatic tea plant pruning. However, the molecular mechanism controlling the branch angle, which is an important aspect of plant architecture, is poorly understood in tea plants. RESULTS: In the present study, three CsLAZY genes were identified from tea plant genome data through sequence homology analysis. Phylogenetic tree displayed that the CsLAZY genes had high sequence similarity with LAZY genes from other plant species, especially those in woody plants. The expression patterns of the three CsLAZYs were surveyed in eight tissues. We further verified the expression levels of the key CsLAZY1 transcript in different tissues among eight tea cultivars and found that CsLAZY1 was highly expressed in stem. Subcellular localization analysis showed that the CsLAZY1 protein was localized in the plasma membrane. CsLAZY1 was transferred into Arabidopsis thaliana to investigate its potential role in regulating shoot development. Remarkably, the CsLAZY1 overexpressed plants responded more effectively than the wild-type plants to a gravity inversion treatment under light and dark conditions. The results indicate that CsLAZY1 plays an important role in regulating shoot gravitropism in tea plants. CONCLUSIONS: The results provide important evidence for understanding the functions of CsLAZY1 in regulating shoot gravitropism and influencing the stem branch angle in tea plants. This report identifies CsLAZY1 as a promising gene resource for the improvement of tea plant architecture.
Assuntos
Camellia sinensis/genética , Genoma de Planta/genética , Gravitropismo/genética , Arabidopsis/genética , Arabidopsis/fisiologia , Camellia sinensis/fisiologia , Filogenia , Brotos de Planta/genética , Brotos de Planta/fisiologia , Caules de Planta/genética , Caules de Planta/fisiologia , CháRESUMO
Drought stress (DS) is the most important abiotic stress affecting yield and quality of tea worldwide. DS causes oxidative stress to cells due to the accumulation of reactive oxygen species (ROS). As non-enzymatic antioxidants, tea catechins can scavenge excess ROS in response to DS. Further, catechin accumulation contributes to the formation of oxidative polymerization products (e.g. theaflavins and thearubigins) that improve the quality of black tea. However, there are no systematic reports on the response of tea catechins to DS. First, we reviewed the available literature on the response of tea plants to DS. Second, we summarized the current knowledge of ROS production in tea leaves under DS and typical antioxidant response mechanisms. Third, we conducted a detailed review of the changes in catechin levels in tea under different drought conditions. We found that the total amounts of catechin and o-quinone increased under DS conditions. We propose that the possible mechanisms underlying tea catechin accumulation under DS conditions include (i) autotrophic formation of o-quinone, (ii) polymerization of proanthocyanidins that directly scavenge excess ROS, and (iii) formation of metal ion complexes and by influencing the antioxidant systems that indirectly eliminate excess ROS. Finally, we discuss ways of potentially improving black tea quality using drought before picking in the summer/fall dry season. In summary, we mainly discuss the antioxidant mechanisms of tea catechins under DS and the possibility of using drought to improve black tea quality. Our review provides a theoretical basis for the production of high-quality black tea under DS conditions. © 2021 Society of Chemical Industry.
Assuntos
Camellia sinensis/fisiologia , Catequina/metabolismo , Secas , Antioxidantes/química , Antioxidantes/metabolismo , Camellia sinensis/química , Camellia sinensis/genética , Catequina/química , Estresse Oxidativo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Estresse Fisiológico , Água/análise , Água/metabolismoRESUMO
The tea plant (Camellia sinensis) is a thermophilic cash crop and contains a highly duplicated and repeat-rich genome. It is still unclear how DNA methylation regulates the evolution of duplicated genes and chilling stress in tea plants. We therefore generated a single-base-resolution DNA methylation map of tea plants under chilling stress. We found that, compared with other plants, the tea plant genome is highly methylated in all three sequence contexts, including CG, CHG and CHH (where H = A, T, or C), which is further proven to be correlated with its repeat content and genome size. We show that DNA methylation in the gene body negatively regulates the gene expression of tea plants, whereas non-CG methylation in the flanking region enables a positive regulation of gene expression. We demonstrate that transposable element-mediated methylation dynamics significantly drives the expression divergence of duplicated genes in tea plants. The DNA methylation and expression divergence of duplicated genes in the tea plant increases with evolutionary age and selective pressure. Moreover, we detect thousands of differentially methylated genes, some of which are functionally associated with chilling stress. We also experimentally reveal that DNA methyltransferase genes of tea plants are significantly downregulated, whereas demethylase genes are upregulated at the initial stage of chilling stress, which is in line with the significant loss of DNA methylation of three well-known cold-responsive genes at their promoter and gene body regions. Overall, our findings underscore the importance of DNA methylation regulation and offer new insights into duplicated gene evolution and chilling tolerance in tea plants.
Assuntos
Camellia sinensis/genética , Metilação de DNA , Elementos de DNA Transponíveis/genética , Evolução Molecular , Genes Duplicados/genética , Genoma de Planta/genética , Camellia sinensis/fisiologia , Temperatura Baixa , Regulação da Expressão Gênica de Plantas , Tamanho do Genoma , Estresse FisiológicoRESUMO
Tea plant (Camellia sinensis) is a well-known Al-accumulating plant, showing a high level of aluminum (Al) tolerance. However, the molecular mechanisms of Al tolerance and accumulation are poorly understood. We carried out transcriptome analysis of tea plant leaves in response to three different Al levels (0, 1, 4 mM, for 7 days). In total, 794, 829 and 585 differentially expressed genes (DEGs) were obtained in 4 mM Al vs. 1 mM Al, 0 Al vs. 1 mM Al, and 4 mM Al vs. 0 Al comparisons, respectively. Analysis of genes related to polysaccharide and cell wall metabolism, detoxification of reactive oxygen species (ROS), cellular transport, and signal transduction were involved in the Al stress response. Furthermore, the transcription factors such as zinc finger, myeloblastosis (MYB), and WRKY played a critical role in transcriptional regulation of genes associated with Al resistance in tea plant. In addition, the genes involved in phenolics biosynthesis and decomposition were overwhelmingly upregulated in the leaves treated with either 0 Al and 4 mM Al stress, indicating they may play an important role in Al tolerance. These results will further help us to understand mechanisms of Al stress and tolerance in tea plants regulated at the transcriptional level.
Assuntos
Alumínio/toxicidade , Camellia sinensis/genética , Camellia sinensis/fisiologia , Regulação da Expressão Gênica de Plantas , Folhas de Planta/genética , Folhas de Planta/fisiologia , Estresse Fisiológico/genética , Transcriptoma/genética , Antioxidantes/metabolismo , Transporte Biológico/genética , Camellia sinensis/efeitos dos fármacos , Parede Celular/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ontologia Genética , Genoma de Planta , Inativação Metabólica/efeitos dos fármacos , Anotação de Sequência Molecular , Pectinas/metabolismo , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/enzimologia , Polissacarídeos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Reprodutibilidade dos Testes , Análise de Sequência de RNA , Transdução de Sinais/genética , Estresse Fisiológico/efeitos dos fármacos , Fatores de Transcrição/metabolismo , Transcriptoma/efeitos dos fármacosRESUMO
KEY MESSAGE: Combined transcriptome and metabolome analysis of fresh leaf infestation by tea green leafhoppers (Empoasca (Matsumurasca) onukii Matsuda) suggests roles for alternative pre-mRNA splicing and mRNAs in the regulation of aroma formation in tea plants. Oriental Beauty is a high-grade, oolong tea with a pronounced honey-like aroma and rich ripe fruit flavor that develops primarily as a result of the infestation of the fresh leaves by tea green leafhoppers (Empoasca (Matsumurasca) onukii Matsuda). Here, we used PacBio Iso-Seq and RNA-seq analyses to determine the full-length transcripts and gene expression profiles of fresh tea leaves in response to E. (M.) onukii herbivory. We investigated the relationship between RNA-seq, tea metabolites, and aroma response mechanisms in leaves infested by leafhoppers. We found 3644 differentially expressed genes, of which 2552 were up- and 1092 were down-regulated. A total of 49,913 alternative splicing events were predicted, including 324 differential AS events. Moreover, 3105 differentially expressed transcripts were also identified, of which 2295 were up- and 810 were down-regulated. The characterization of expression patterns of the key gene transcript isoforms involved in the aroma formation pathways identified 130 differentially expressed metabolites, 97 of which were up- and 33 were down-regulated. Two key aroma compounds (phenylacetaldehyde and 4-hydroxybenzaldehyde) were highly correlated with genes of the aroma formation pathways. Our results revealed that pre-mRNA AS plays a crucial role in the metabolic regulation surrounding aroma formation under leafhopper herbivory in tea plants.
Assuntos
Camellia sinensis/fisiologia , Hemípteros , Folhas de Planta/fisiologia , Compostos Orgânicos Voláteis/metabolismo , Processamento Alternativo , Animais , Carotenoides/metabolismo , Ácidos Graxos/genética , Ácidos Graxos/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Hemípteros/fisiologia , Metaboloma , Terpenos/metabolismoRESUMO
Tea (Camellia sinensis [L.] O. Kuntze) tree is a perennial plant in which winter dormancy is an important biological adaptation to environmental changes. We discovered and reported a novel tea tree cultivar that can generate tender shoots in winter several years ago, but the molecular mechanism for this unique phenotype remains unknown . Here, we conducted comparative transcriptomics, proteomics and metabolomics along with phytohormone quantitation between the winter and spring tender shoots to investigate the physiological basis and putative regulatory mechanisms of its evergrowing character during winter. Our multi-omics study has led to the following findings. Gibberellin (GA) levels and key enzymes for GA biosynthesis and the signal transduction pathway were increased in the winter shoots, causing the ABA/GA content ratio to decrease, which might play a key regulatory role in maintaining normal growth during winter. The abundance of proteins, genes and metabolites involved in energy metabolism was all increased in winter shoots, indicating that energy is critical for continuous growth under the relatively weak-light and low-temperature environment. Abiotic resistance-related proteins and free amino acids were also increased in abundance in the winter shoots, which possibly represents an adaptation response to winter conditions. These results allowed us to hypothesize a novel molecular mechanism of adaptation for this unique tender shoot evergrowing in winter.
Assuntos
Camellia sinensis/fisiologia , Brotos de Planta/fisiologia , Adaptação Fisiológica/genética , Adaptação Fisiológica/fisiologia , Camellia sinensis/genética , Camellia sinensis/crescimento & desenvolvimento , Perfilação da Expressão Gênica , Metabolômica , Dormência de Plantas/genética , Dormência de Plantas/fisiologia , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/fisiologia , Proteínas de Plantas/classificação , Proteínas de Plantas/metabolismo , Proteínas de Plantas/fisiologia , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Proteômica , Estações do Ano , Transdução de Sinais/fisiologiaRESUMO
Herbivore-induced plant volatiles play important ecological roles in defense against stresses. However, if and which volatile(s) are involved in the plant-plant communication in response to herbivorous insects in tea plants remains unknown. Here, plant-plant communication experiments confirm that volatiles emitted from insects-attacked tea plants can trigger plant resistance and reduce the risk of herbivore damage by inducing jasmonic acid (JA) accumulation in neighboring plants. The emission of six compounds was significantly induced by geometrid Ectropis obliqua, one of the most common pests of the tea plant in China. Among them, (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) could induce the accumulation of JA and thus promotes the resistance of neighboring intact plants to herbivorous insects. CsCYP82D47 was identified for the first time as a P450 enzyme, which catalyzes the final step in the biosynthesis of DMNT from (E)-nerolidol. Down-regulation of CsCYP82D47 in tea plants resulted in a reduced accumulation of DMNT and significantly reduced the release of DMNT in response to the feeding of herbivorous insects. The first evidence for plant-plant communication in response to herbivores in tea plants will help to understand how plants respond to volatile cues in response to herbivores and provide new insight into the role(s) of DMNT in tea plants.
Assuntos
Alcenos/metabolismo , Camellia sinensis/metabolismo , Ciclopentanos/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Oxilipinas/metabolismo , Defesa das Plantas contra Herbivoria , Reguladores de Crescimento de Plantas/metabolismo , Proteínas de Plantas/metabolismo , Animais , Camellia sinensis/genética , Camellia sinensis/fisiologia , Clonagem Molecular , Comunicação , Sistema Enzimático do Citocromo P-450/genética , Regulação da Expressão Gênica de Plantas , Larva , Mariposas , Reguladores de Crescimento de Plantas/fisiologia , Proteínas de Plantas/genética , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de DNA , Compostos Orgânicos Voláteis/metabolismoRESUMO
Upon herbivore attack, plants emit herbivore-induced plant volatiles (HIPVs). HIPVs can prime defences and resistance of intact plants. However, how HIPVs are decoded and translated into functional defence responses is not well understood, especially in long-lived woody plants. Here, we investigated the impact of the aromatic HIPV indole on defence-related early signalling, phytohormone accumulation, secondary metabolite biosynthesis and herbivore resistance in tea plants. We find that tea plants infested with tea geometrid caterpillars release indole at concentrations >450 ng*hr-1 . Exposure to corresponding doses of synthetic indole primes the expression of early defence genes involved in calcium (Ca2+ ) signalling, MPK signalling and jasmonate biosynthesis. Indole exposure also primes the production of jasmonates and defence-related secondary metabolites. These changes are associated with higher herbivore resistance of indole-exposed tea plants. Chemical inhibition of Ca2+ and jasmonate signalling provides evidence that both are required for indole-mediated defence priming and herbivore resistance. Our systematic assessment of the impact of indole on defence signalling and deployment shows that indole acts by boosting Ca2+ signalling, resulting in enhanced jasmonate-dependent defence and resistance in a woody plant. Our work extends the molecular basis of HIPV-induced defence priming from annual plants to an economically important tree species.