ORCID Profile
0000-0001-5733-1810
Current Organisation
South China Agricultural University
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Publisher: MDPI AG
Date: 30-11-2022
Abstract: Leaf color is one of the key factors involved in determining the processing suitability of tea. It relates to differential accumulation of flavor compounds due to the different metabolic mechanisms. In recent years, photosensitive etiolation or albefaction is an interesting direction in tea research field. However, the molecular mechanism of color formation remains unclear since albino or etiolated mutants have different genetic backgrounds. In this study, wide-target metabolomic and transcriptomic analyses were used to reveal the biological mechanism of leaf etiolation for ‘Huangyu’, a bud mutant of ‘Yinghong 9’. The results indicated that the reduction in the content of chlorophyll and the ratio of chlorophyll to carotenoids might be the biochemical reasons for the etiolation of ‘Huangyu’ tea leaves, while the content of zeaxanthin was significantly higher. The differentially expressed genes (DEGs) involved in chlorophyll and chloroplast biogenesis were the biomolecular reasons for the formation of green or yellow color in tea leaves. In addition, our results also revealed that the changes of DEGs involved in light-induced proteins and circadian rhythm promoted the adaptation of etiolated tea leaves to light stress. Variant colors of tea leaves indicated different directions in metabolic flux and accumulation of flavor compounds.
Publisher: MDPI AG
Date: 02-01-2020
DOI: 10.3390/MOLECULES25010190
Abstract: A variant of tea tree (Camellia sinensis (L.)) with purple buds and leaves and pink flowers can be used as a unique ornamental plant. However, the mechanism of flower coloration remains unclear. To elucidate the molecular mechanism of coloration, as well as anthocyanin accumulation in white and pink tea flowers, metabolite profiling and transcriptome sequencing was analyzed in various tea flower developmental stages. Results of metabolomics analysis revealed that three specific anthocyanin substances could be identified, i.e., cyanidin O-syringic acid, petunidin 3-O-glucoside, and pelargonidin 3-O-β-d-glucoside, which only accumulated in pink tea flowers, and were not able to be detected in white flowers. RNA-seq and weighted gene co-expression network analysis revealed eight highly expressed structural genes involved in anthocyanin biosynthetic pathway, and particularly, different expression patterns of flavonol synthase and dihydroflavonol-4-reductase genes were observed. We deduced that the disequilibrium of expression levels in flavonol synthases and dihydroflavonol-4-reductases resulted in different levels of anthocyanin accumulation and coloration in white and pink tea flowers. Results of qRT-PCR performed for 9 key genes suggested that the expression profiles of differentially expressed genes were generally consistent with the results of high-throughput sequencing. These findings provide insight into anthocyanin accumulation and coloration mechanisms during tea flower development, which will contribute to the breeding of pink-flowered and anthocyanin-rich tea cultivars.
Publisher: Springer Science and Business Media LLC
Date: 29-03-2016
DOI: 10.1038/SREP23685
Abstract: γ-Aminobutyric acid (GABA) is one of the major inhibitory neurotransmitters in the central nervous system. It has multiple positive effects on mammalian physiology and is an important bioactive component of tea ( Camellia sinensis ). GABA generally occurs at a very low level in plants but GABA content increases substantially after exposure to a range of stresses, especially oxygen-deficiency. During processing of tea leaves, a combination of anoxic stress and mechanical damage are essential for the high accumulation of GABA. This is believed to be initiated by a change in glutamate decarboxylase activity, but the underlying mechanisms are unclear. In the present study we characterized factors regulating the expression and activity of three tea glutamate decarboxylase genes ( CsGAD1, 2 and 3 ) and their encoded enzymes. The results suggests that, unlike the model plant Arabidopsis thaliana, there are dual mechanisms regulating the accumulation of GABA in tea leaves exposed to multiple stresses, including activation of CsGAD1 enzymatic activity by calmodulin upon the onset of the stress and accumulation of high levels of CsGAD2 mRNA induced by a combination of anoxic stress and mechanical damage.
Publisher: Public Library of Science (PLoS)
Date: 26-12-2019
No related grants have been discovered for Lingyun Zhang.