Integrated metabolomic and transcriptomic strategies to understand the effects of dark stress on tea callus flavonoid biosynthesis

A short treatment of excised buckwheat cotyledons with a solution of kinetin lead to an up to 9-fold stimulation of anthocyanin biosynthesis, to an about 50 percent increase in the accumulation of rutin, and to an about 30 percent increase, on the average, in the accumulation of C-glycosylflavones in the treated material during its posttreatment incubation in the dark. When the treated cotyledons were incubated in a solution of ʟ--phenylalanine anthocyanin accumulation in the dark practically attained the same high level as it was observed in the illuminated cotyledons fed with exogenous ʟ--phenylalanine. In experiments with l4C-labelled L-phenylalanine kinetin induced a sharp rise in the labelling (resp. in the utilization of exogenous substrate for biosynthesis) of anthocyanins and rutin in the dark and a slight increase in the radioactivity of C-glycosylflavones. Similar labelling changes occurred in the illuminated cotyledons. However, both kinetin and light still more effectively promoted biosynthetic use of the endogenous substrate. As a result the relative portion of flavonoids formed from exogenous L-phenylalanine under these conditions showed a decrease as compared with the ratio of precursor use in the untreated cotyledons. The results show that low accumulation rates of anthocyanins and other flavonoids in the dark are conditioned by the limited access of substrate (ʟ--phenylalanine) molecules to the flavonoid enzymes lending further support to the idea that flavonoid biosynthesis is normally controlled at the substrate rather than at the enzymic level.

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NtbHLH1, a JAF13-like bHLH, interacts with NtMYB6 to enhance proanthocyanidin accumulation in Chinese Narcissus

BMC Plant Biology ◽

10.1186/s12870-021-03050-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Yuxin Fan ◽

Jiayu Peng ◽

Jiacheng Wu ◽

Ping Zhou ◽

Ruijie He ◽

...

Keyword(s):

Flavonoid Biosynthesis ◽

Transcriptional Level ◽

Flavonoid Pathway ◽

Regulation Of Expression ◽

Over Expression ◽

Expression Of Genes ◽

Genes Encoding ◽

Regulatory Complex ◽

Positive Regulators ◽

R2r3 Myb

Abstract Background Flavonoid biosynthesis in plants is primarily regulated at the transcriptional level by transcription factors modulating the expression of genes encoding enzymes in the flavonoid pathway. One of the most studied transcription factor complexes involved in this regulation consists of a MYB, bHLH and WD40. However, in Chinese Narcissus (Narcissus tazetta L. var. chinensis), a popular monocot bulb flower, the regulatory mechanism of flavonoid biosynthesis remains unclear. Results In this work, genes related to the regulatory complex, NtbHLH1 and a R2R3-MYB NtMYB6, were cloned from Chinese Narcissus. Phylogenetic analysis indicated that NtbHLH1 belongs to the JAF13 clade of bHLH IIIf subgroup, while NtMYB6 was highly homologous to positive regulators of proanthocyanidin biosynthesis. Both NtbHLH1 and NtMYB6 have highest expression levels in basal plates of Narcissus, where there is an accumulation of proanthocyanidin. Ectopic over expression of NtbHLH1 in tobacco resulted in an increase in anthocyanin accumulation in flowers, and an up-regulation of expression of the endogenous tobacco bHLH AN1 and flavonoid biosynthesis genes. In contrast, the expression level of LAR gene was significantly increased in NtMYB6-transgenic tobacco. Dual luciferase assays showed that co-infiltration of NtbHLH1 and NtMYB6 significantly activated the promoter of Chinese Narcissus DFR gene. Furthermore, a yeast two-hybrid assay confirmed that NtbHLH1 interacts with NtMYB6. Conclusions Our results suggest that NtbHLH1 may function as a regulatory partner by interacting directly with NtMYB6 to enhance proanthocyanidin accumulation in Chinese Narcissus.

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Drought Resistance in Qingke Involves a Reprogramming of the Phenylpropanoid Pathway and UDP-Glucosyltransferase Regulation of Abiotic Stress Tolerance Targeting Flavonoid Biosynthesis

Journal of Agricultural and Food Chemistry ◽

10.1021/acs.jafc.0c07810 ◽

2021 ◽

Author(s):

Congping Xu ◽

Lingling Wei ◽

Sishu Huang ◽

Chunbao Yang ◽

Yulin Wang ◽

...

Keyword(s):

Abiotic Stress ◽

Stress Tolerance ◽

Drought Resistance ◽

Abiotic Stress Tolerance ◽

Phenylpropanoid Pathway ◽

Flavonoid Biosynthesis

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Transcriptome and metabolome analyses revealing the potential mechanism of seed germination in Polygonatum cyrtonema

Scientific Reports ◽

10.1038/s41598-021-91598-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Rong Liu ◽

Jing Lu ◽

Jiayi Xing ◽

Mei Du ◽

Mingxiu Wang ◽

...

Keyword(s):

Seed Germination ◽

Organic Acids ◽

Plant Hormones ◽

Regulatory Networks ◽

Amylase Activity ◽

Flavonoid Biosynthesis ◽

Market Demand ◽

Potential Mechanism ◽

Flavonoid Synthesis ◽

Germinated Seeds

AbstractPolygonatum cyrtonema Hua (Huangjing, HJ) has medicinal and edible value in China. However, the seeds of this plant are naturally difficult to germinate. Therefore, to elucidate the mechanism underlying the germination of this plant in order to meet the market demand, the metabolomic and transcriptomic analyses were performed in this study. We observed that plant hormones and α-amylase activity were differentially regulated when comparing germinated and un-germinated seeds. In addition, the metabolites related to phenylpropanoid and flavonoid biosynthesis were significantly up-accumulated in germinated seeds. Hydroxycinnamoyl derivatives and organic acids were observed to be significantly decreased during germination. The results of this study suggested that compared to un-germinated seeds, germinated seeds promote flavonoid synthesis and inhibit lignin synthesis which could be beneficial to the germination of HJ seeds. Furthermore, these results suggested that starch if hydrolyzed into glucose, which could provide the necessary energy for germination. Our results may help to establish a foundation for further research investigating the regulatory networks of seed germination and may facilitate the propagation of HJ seeds.

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Comparative Transcriptome Analysis Reveals Key Genes and Pathways Involved in Prickle Development in Eggplant

Genes ◽

10.3390/genes12030341 ◽

2021 ◽

Vol 12 (3) ◽

pp. 341

Author(s):

Lei Zhang ◽

Haoyun Sun ◽

Tao Xu ◽

Tianye Shi ◽

Zongyun Li ◽

...

Keyword(s):

Transcriptome Analysis ◽

Morphological Analysis ◽

Molecular Mechanisms ◽

Flavonoid Biosynthesis ◽

Phenotypic Characterization ◽

Comparative Transcriptome ◽

Hub Genes ◽

Breeding Programs ◽

Comparative Transcriptome Analysis ◽

Key Pathways

Eggplant is one of the most important vegetables worldwide. Prickles on the leaves, stems and fruit calyxes of eggplant may cause difficulties during cultivation, harvesting and transportation, and therefore is an undesirable agronomic trait. However, limited knowledge about molecular mechanisms of prickle morphogenesis has hindered the genetic improvement of eggplant. In this study, we performed the phenotypic characterization and transcriptome analysis on prickly and prickleless eggplant genotypes to understand prickle development at the morphological and molecular levels. Morphological analysis revealed that eggplant prickles were multicellular, lignified and layered organs. Comparative transcriptome analysis identified key pathways and hub genes involved in the cell cycle as well as flavonoid biosynthetic, photosynthetic, and hormone metabolic processes during prickle development. Interestingly, genes associated with flavonoid biosynthesis were up-regulated in developing prickles, and genes associated with photosynthesis were down-regulated in developing and matured prickles. It was also noteworthy that several development-related transcription factors such as bHLH, C2H2, MYB, TCP and WRKY were specifically down- or up-regulated in developing prickles. Furthermore, four genes were found to be differentially expressed within the Pl locus interval. This study provides new insights into the regulatory molecular mechanisms underlying prickle morphogenesis in eggplant, and the genes identified might be exploited in breeding programs to develop prickleless eggplant cultivars.

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Down-Regulation of SlGRAS10 in Tomato Confers Abiotic Stress Tolerance

Genes ◽

10.3390/genes12050623 ◽

2021 ◽

Vol 12 (5) ◽

pp. 623

Author(s):

Sidra Habib ◽

Yee Yee Lwin ◽

Ning Li

Keyword(s):

Salt Stress ◽

Abiotic Stress ◽

Plant Growth ◽

Stress Tolerance ◽

Abiotic Stresses ◽

Abiotic Stress Tolerance ◽

Functional Characterization ◽

Flavonoid Biosynthesis ◽

Ros Scavenging ◽

Down Regulation

Adverse environmental factors like salt stress, drought, and extreme temperatures, cause damage to plant growth, development, and crop yield. GRAS transcription factors (TFs) have numerous functions in biological processes. Some studies have reported that the GRAS protein family plays significant functions in plant growth and development under abiotic stresses. In this study, we demonstrated the functional characterization of a tomato SlGRAS10 gene under abiotic stresses such as salt stress and drought. Down-regulation of SlGRAS10 by RNA interference (RNAi) produced dwarf plants with smaller leaves, internode lengths, and enhanced flavonoid accumulation. We studied the effects of abiotic stresses on RNAi and wild-type (WT) plants. Moreover, SlGRAS10-RNAi plants were more tolerant to abiotic stresses (salt, drought, and Abscisic acid) than the WT plants. Down-regulation of SlGRAS10 significantly enhanced the expressions of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) to reduce the effects of reactive oxygen species (ROS) such as O2− and H2O2. Malondialdehyde (MDA) and proline contents were remarkably high in SlGRAS10-RNAi plants. Furthermore, the expression levels of chlorophyll biosynthesis, flavonoid biosynthesis, and stress-related genes were also enhanced under abiotic stress conditions. Collectively, our conclusions emphasized the significant function of SlGRAS10 as a stress tolerate transcription factor in a certain variety of abiotic stress tolerance by enhancing osmotic potential, flavonoid biosynthesis, and ROS scavenging system in the tomato plant.

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Purification of Chalcone Synthase from Tulip Anthers and Comparison with the Synthase from Cosmos Petals

Zeitschrift für Naturforschung C ◽

10.1515/znc-1981-1-207 ◽

1981 ◽

Vol 36 (1-2) ◽

pp. 30-34 ◽

Cited By ~ 16

Author(s):

Rainer Sütfeld ◽

Rolf Wiermann

Keyword(s):

Chalcone Synthase ◽

In Vitro Assay ◽

Flavonoid Biosynthesis ◽

Chalcone Isomerase ◽

Gel Chromatography ◽

Purification Procedure ◽

Reaction Products ◽

Complete Elimination ◽

Vitro Assay

Abstract Chalcone synthase was isolated from both anthers of Tulipa cv. “Apeldoorn” and petals of Cosmos sulphureus Cav. After certain prepurification steps, the enzymes were further purified using gel chromatography on Sephadex G-200 followed by repeated hydroxylapatite absorption chromatography. Both the enzymes showed the same chromatographic properties. After gel chromatography as well as after the first hydroxylapatite fractionation, the reaction products appeared as flavanones. However, after the second hydroxylapatite step, production of chalcones was observed. Like the enzyme from tulip anthers, the synthase from Cosmos petals produced the correspondingly substituted chalcones when p-coumaroyl-CoA, caffeoyl-CoA and feruloyl-CoA, respectively, were used as substractes. In both the cases, the ratios of the different chalcones produced were found to be about the same. The appearance of chalcone synthesis in this in vitro assay is caused by the complete elimination of chalcone isomerase in the purification procedure. The importance of the isomerase for flavonoid biosynthesis, particularly in plant systems which are accumulating chalcones, is discussed.

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