Project description:Leaf rolling and discoloration are two chilling injury symptoms that are widely adopted as indicators for evaluation of cold tolerance at the seedling stage in rice, respectively. However, their relationship has not been well investigated, in particular the mechanism on how low temperature causes leaf rolling at a genome-wide level. In this study, a cold-tolerant japonica cultivar Lijiangxintuanheigu and a cold-sensitive indica cultivar Sanhuangzhan-2 were subjected to different low temperature treatments and physiological and genome-wide gene expression analysis were conducted. Our results showed that leaf rolling happened at temperatures lower than 11℃, but discoloration appeared at moderately low temperatures, such as 13℃. Chlorophyll contents of the two cultivars significantly decreased under 13℃, but didn’t change under 11℃. Contrastly, their relative water contents and the relative electrolyte leakages decreased significantly. Genome-wide gene expression profiling of LTH revealed that the calcium signaling related genes and the genes related to ABA degradation significantly changed under 11℃. Moreover, numerous genes in DREB, MYB, bZIP, NAC, Zin finger, bHLH, WRKY gene families were differently expressed. Furthermore, many aquaporin genes, the key genes in trehalose and starch synthesis were down-regulated under 11℃. These results suggest that the two chilling injury symptoms are controlled by different mechanisms. Cold-induced leaf rolling is associated with calcium and ABA signaling pathways, and subjected to regulation of multiple transcription regulators. The suppression of aquaporin genes and reduced accumulation of soluble sugars under cold stress result in reduction of water potential in cells and consequently, leaf rolling.
Project description:The RNA-Seq was used to analyze the expression profiling of genes in different ablescent stages of 'Anji Baicha' Examination of three tea leaf samples in yellow stage, white stage and green stage
Project description:An increasing amount of evidence attest that the tea made by albino tea cultivars processes characteristic aroma and taste, which has been considered as a new potential product in the market. Therefore, flavor formation mechanism of albino tea cultivars have drawn exceeding attention from researchers. In this study, transcriptome, metabolomics, and whole-genome bisulfite sequencing (WGBS) were employed to investigate shading effects on leaf color conversion and biosynthesis of three major secondary metabolites in the Albino tea cultivar ‘Yujinxiang’. The increase of leaf chlorophyll level is the major cause of shaded leaf greening from young pale or yellow leaf. Transcriptome analysis showed differentially expressed genes (DEGs) mainly participated in biosynthesis of amino acids, phenylalanine metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, sulfur metabolism, purine metabolism, and pentose and glucuronate interconversions in shading period compared with control group. The result of metabolomics indicated the total catechins level of shading group was significantly decreased than the control; however, the abundance of caffeine was markedly increased, and theanine level was nearly not influenced. Whole-genome DNA methylation analysis revealed that the global genomic DNA methylation patterns of shading period were remarkably altered compared with the control. Furthermore, differentially methylated regions (DMRs) and the DMR-related DEGs between shading and non-shading analysis indicated the DMR-related DEGs were the critical participants in biosynthesis of three major secondary metabolites. To sum up, these findings suggested that the altered levels of DNA methylation may be the main cause for biosynthesis changes of three major secondary metabolites in ‘Yujinxiang’.
Project description:The tea plant (Camellia sinensis (L.) O. Kuntze) is often commercially used as a source of non-alcoholic beverages and is an economically important woody crop (Chen et al., 2007). As living standards have improved, the requirement for high-quality life has increased in modern society. ‘Anji Baicha’ (alias ‘Baiye 1’ or ‘White Leaf 1’) is an excellent tea cultivar with albino phenotype and it is popular in producing high-quality green tea. The traits of ‘Anji Baicha’ are as follows. Young ‘Anji Baicha’ shoots are yellow-green when the early spring temperature is below 20°C. As the leaves fully expand, the leaves become white. The leaves gradually return to green when the environmental temperature increases (Cheng et al., 1999; Li et al., 2002, 2011). Previous reports have suggested a positive correlation between amino acid concentration and albinism as well as a negative correlation between tea polyphenols and albinism (Li et al., 1996; Du et al., 2006; Xiong et al., 2013). Therefore, the quality of ‘Anji Baicha’ is much higher when new shoots become albino due to their rich amino acid content and modest tea polyphenol content. Plants adjust their metabolism in response to environmental stimuli to eventually bring about changes in protein activities and levels, and this adaptive process includes posttranslational protein modifications (PTMs) (Prabakaran et al., 2012). PTMs have been reported to regulate various processes, including DNA interaction, protein-protein interactions, enzyme activation and protein stability. Among the hundreds of different PTMs, lysine acetylation is an abundant, reversible and highly regulated PTM (Zhang et al., 2009; Wu et al., 2011).
Project description:Mussaenda pubescens (Mp) is a valuable medicinal plant that has traditionally been used for medicinal purposes or as a tea substitute. However, there are few studies on the comprehensive and dynamic evaluation of Mp metabolites presented in Mp. This study used an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) approach and biochemical analysis to investigate substance changes in leaves at three different stages and elucidate the relationship between metabolites and antioxidant capacity. The findings showed that MpP leaves contained 957 metabolites, the majority of which were phenolic acids, lipids, and terpenoids. The metabolite profiling of Mp leaves was significantly influenced by their growth and development at different stages. A total of 317 differentially accumulated metabolites (DAMs) were screened, including 150 primary metabolites and 167 secondary metabolites, with 202 DAMs found in bud leaf vs. tender leaf, 54 DAMs in tender leaf vs. mature leaf, and 254 DAMs in bud leaf vs. mature leaf. Total phenolics, flavonoids, and anthocyanin concentrations decreased as Mp leaves grew and developed, whereas terpenoids increased significantly. The secondary metabolites also demonstrated a positive correlation with antioxidant activity. Phenolics, flavonoids, terpenoids, and anthocyanins were the primary factors influencing the antioxidant activity of leaves. These findings provide new insights into the metabolite formation mechanism, as well as the development and utilization of Mp tea.
Project description:BACKGROUND: Evaluation of the airway transcriptome may reveal patterns of gene expression that are associated with clinical phenotypes of asthma. To define transcriptomic endotypes of asthma (TEA) we analyzed gene expression in induced sputum that correlate with phenotypes of disease. METHODS: Gene expression was measured in sputum of subjects with asthma using Affymetrix HuGene ST 1.0 microarrays. Unsupervised clustering analysis of genes in pathways selected from the Kyoto Encyclopedia of Genes and Genomes (KEGG) identified TEA clusters. Clinical characteristics were compared and logistic regression analysis of matched blood samples defined an expression profile to determine the TEA cluster assignment in a cohort of children with asthma for validation. RESULTS: Three TEA clusters were identified. TEA cluster 1 had the most subjects with a history of intubation (P = 0.05), a lower pre-bronchodilator FEV1 (P = 0.006), a higher bronchodilator response (P = 0.03), and higher exhaled nitric oxide levels (P = 0.04), compared to the other TEA clusters. TEA cluster 2, the smallest cluster had the most subjects that were hospitalized for asthma (P = 0.04). Subjects in TEA cluster 3, the largest cluster, had normal lung function, low exhaled nitric oxide levels, and lower inhaled steroid requirements. Evaluation of TEA clusters in children confirmed that TEA clusters 1 and 2 are associated with a history of intubation (P = 5.58 x 10-06) and hospitalization (P = 0.01), respectively. CONCLUSIONS: Patterns of gene expression in the sputum and blood reveal TEA clusters that are associated with severe asthma phenotypes in children and adults. Gene expression was measured in sputum of subjects with asthma using Affymetrix HuGene ST 1.0 microarrays. Unsupervised clustering analysis of genes in pathways selected from the Kyoto Encyclopedia of Genes and Genomes (KEGG) identified TEA clusters. Clinical characteristics were compared and logistic regression analysis of matched blood samples defined an expression profile to determine the TEA cluster assignment in a cohort of children with asthma for validation.