Tannin Accumulation Research Articles

Growth potential, biochemical properties and nutrient removal efficiency of some freshwater microalgae and their consortia from wastewater

Impact of varying nitrate (NO3-N) and phosphate (PO4-P) concentrations and sewage water (SW) on the growth, nutrient removal, lipid accumulation, enzymatic antioxidant activity and phytochemical contents of the microalgae Scenedesmus dimorphus, Coelastrella tenuitheca, Chroococcus turgidus and Parachlorella kessleri under monoculture and their consortia have been investigated. High growth rates were observed for all the four algae in both mono and mixed culture conditions at enhanced concentrations of N (1500 mg/L NO3-N) and P (40 mg/L PO4-P). The species Scenedesmus dimorphus outperformed other microalgae growing in SW in efficiently removing nitrogen. The algal consortia of mixed species was found to be more effective in phosphorus removal. The carbohydrate and protein contents were highest in Parachlorella kessleri, about 37% and 44%, respectively, in SW cultivation. The algal consortia demonstrated highest starch content (4%) in nitrogen deprived growth medium. Highest lipid production (43%) was observed in the SW culture. The species Coelastrella tenuitheca, Chroococcus turgidus and Scenedesmus dimorphus irrespective of the growth media indicated significant accumulation of phenol, flavonoid and tannin. The DPPH, catalase and ascorbic peroxidase assay showed pronounced antioxidant activity. Nutrient (N and P) enrichment exhibited enhanced antioxidant enzymatic activity and accumulation of cell storage products.

Canopy-Applied Benzothiadiazole (BTH) during the Pre-Harvest Period as a Tool to Increase Polyphenol Accumulation and Color Intensity in Cabernet Gernischt and Cabernet Franc

Despite the wealth of studies on benzothiadiazole (BTH) and its capacity to modulate grape polyphenol metabolism, comprehensive data detailing polyphenol accumulation at various grape growth stages remain scarce. Therefore, the present study utilized pre-harvest (at 21 days after flowering) canopy-applied BTH (50 mg/L) on Cabernet Gernischt and Cabernet Franc grapes to investigate the physicochemical and polyphenolic changes during grape maturation. The results showed that BTH treatment significantly affected the accumulation of total phenols, flavonoids, flavanols, anthocyanins, and tannins. Concurrently, it induced an increase in colorimetric parameters (CIRG, L*, b*, a*, and C*ab), resulting in the treated grapes exhibiting a greater color intensity and enhanced red-bluish colorimetric characteristics. Moreover, the BTH treatment amplified the anthocyanin content in the grapes, with the levels of petunidin-3-O-glucoside and peonidin-3-O-glucoside exhibiting remarkable increases, particularly in the Cabernet Franc grape. Notably, the content of peonidin-3-O-glucoside even surpassed that of malvidin-3-O-glucoside throughout the growth stages, indicating significant advantages in the treated samples. Additionally, the levels of flavanol, flavonols, phenolic acids, and stilbenes experienced a significant boost post-treatment. In conclusion, the application of BTH treatment can effectively enhance the accumulation of polyphenols and intensify the color of Cabernet Gernischt and Cabernet Franc grapes, thereby significantly improving the overall quality of wine grapes and ensuring the production of higher-quality wines. The research findings will serve as a theoretical foundation and provide scientific data for the appropriate utilization of BTH in wine grape cultivation.

Post-veraison sunlight supplementation improved the phenolic profile of Cabernet Gernischt (Vitis vinifera L.) grape and wine in a temperate monsoon climate

The regulation of solar radiation is a pivotal agricultural practice in enhancing the quality of grapes and subsequently, wine. In regions like Yantai, where solar radiation levels are typically low, the accumulation of wine phenolic compounds is negatively impacted. In light of this, our study sought to assess the efficacy of silver reflective mulch (RM) treatment on grape yield, maturity, and phenolic composition. Specifically, we applied RM treatment post-veraison to a Cabernet Gernischt (Vitis vinifera L.) vineyard in the Yantai wine region of China. Our findings indicate a consistent improvement in grape maturity with RM treatment, alongside enhanced accumulation of total phenols (TP), total tannins (TT), and total anthocyanins (TAC) in grape skin. Consequently, this led to elevated levels of phenolic compounds in wines and heightened color intensity. Moreover, tandem mass spectrometry analysis unveiled higher concentrations of key compounds such as petunidin-3-glucoside, malvidin-3-glucoside, procyanidin B1, quercetin-3-glucoside, cis-resveratrol, and piceatannol in the resultant wines. This study underscores the potential of RM treatment to bolster wine phenolics, particularly in regions characterized by a Temperate Monsoon Climate.

Urban Flora Riches: Unraveling Metabolic Variation Along Altitudinal Gradients in Two Spontaneous Plant Species.

Using resilient, self-sustaining plants in urban green spaces enhances environmental and cultural benefits and reduces management costs. We assessed two spontaneous plant species, Linaria vulgaris Mill. and Cichorium intybus L., in four sites from the surrounding urban areas, ranging in altitude from 78 to 1040 m. Protection against UV-B radiation is crucial for plants at higher altitudes, guiding our focus on UV-visible absorption spectra, fluorometric emission spectra, secondary metabolite accumulation, and pigment dynamics in leaves. Our findings revealed a slight increase in UV-absorbing compounds with altitude and species-specific changes in visible spectra. The UV-emission of fluorochromes decreased, while red emission increased with altitude but only in chicory. Polyphenols and flavonoids showed a slight upward trend with altitude. Divergent trends were observed in condensed tannin accumulation, with L. vulgaris decreasing and C. intybus increasing with altitude. Additionally, chicory leaves from higher altitudes (792 and 1040 m) contained significantly lower triterpene concentrations. In L. vulgaris, chlorophyll pigments and carotenoids varied with sites, contrasting with UV absorbance variations. For C. intybus, pigment variation was similar to absorbance changes in the UV and VIS range, except at the highest altitude. These observations provide valuable insights into species-specific strategies for adapting to diverse environmental contexts.

Bacillus sp. A8a reduces leaf wilting by Phytophthora and modifies tannin accumulation in avocado

The objective was to assess the biocontrol capacity of Bacillus sp. A8a in avocado (Persea americana) plants infected by Phytophthora cinnamomi. A greenhouse experiment was implemented with four treatments: 1) control plants; 2) plants infected with P. cinnamomi; 3) plants inoculated with Bacillus sp. A8a; 4) plants infected with P. cinnamomi and inoculated with Bacillus sp. A8a. We evaluated several morpho-physiological variables during the experiment, which lasted 25 days after infection (dai). Moreover, we analyzed tannin density in stems at 25 dai to determine the plant defense response against the disease. Inoculation with strain A8a reduced wilting symptoms by 49 % at 25 dai, compared with non-inoculated plants. No differences were detected in morphophysiological variables between treatments. However, a greater tannin accumulation was registered in the xylem of infected plants, whilst plants inoculated with strain A8a displayed a larger tannin density in the cortex. Our results confirm the biocontrol activity of Bacillus sp. A8a in avocado plants and suggest that tannin differential accumulation in the cortex of plants inoculated with the bacteria may contribute to the enhanced tolerance of avocado plants against Phytophthora root rot.

Unraveling the occasional occurrence of berry astringency in table grape cv. Scarlet Royal: a physiological and transcriptomic analysis.

Scarlet Royal, a mid-season ripening table grape, is one of the popular red grape varieties in California. However, its berries develop an undesirable astringent taste under certain conditions. Among the various factors contributing to the degradation of berry attributes, the levels and compositions of polyphenols play a fundamental role in defining berry quality and sensory characteristics. To comprehend the underlying mechanism of astringency development, Scarlet Royal berries with non-astringent attributes at the V7 vineyard were compared to astringent ones at the V9 vineyard. Biochemical analysis revealed that the divergence in berry astringency stemmed from alterations in its polyphenol composition, particularly tannins, during the late ripening stage at the V9 vineyard. Furthermore, transcriptomic profiling of berries positively associated nineteen flavonoid/proanthocyanidins (PAs) structural genes with the accumulation of PAs in V9 berries. The identification of these genes holds significance for table grape genetic improvement programs. At a practical level, the correlation between the taste panel and tannin content revealed a threshold level of tannins causing an astringent taste at approximately 400 mg/L. Additionally, berry astringency at the V9 vineyard was linked to a lower number of clusters and yield during the two study seasons, 2016 and 2017. Furthermore, petiole nutrient analysis at bloom showed differences in nutrient levels between the two vineyards, including higher levels of nitrogen and potassium in V9 vines compared to V7. It's worth noting that V9 berries at harvest displayed a lower level of total soluble solids and higher titratable acidity compared to V7 berries. In conclusion, our results indicate that the accumulation of tannins in berries during the ripening process results in a reduction in their red color intensity but significantly increases the astringency taste, thereby degrading the berry quality attributes. This study also highlights the association of high nitrogen nutrient levels and a lower crop load with berry astringency in table grapes, paving the way for further research in this area.

Comparative Metabolomic and Transcriptomic Analyses Reveal Distinct Ascorbic Acid (AsA) Accumulation Patterns between PCA and PCNA Persimmon Developing Fruit.

Persimmon fruit has a high nutritional value and significantly varies between pollination-constant astringent (PCA) and pollination-constant non-astringent (PCNA) persimmons. The astringency type affects sugar, flavonoids, and tannin accumulation and is well known in persimmon fruit. However, the impact of the fruit astringency type on ascorbic acid (AsA) accumulation is limited. In this study, typical PCA varieties ('Huojing' and 'Zhongshi5') and PCNA varieties ('Yohou' and 'Jiro') of persimmon fruit were sampled at four developing stages (S1-S4) to provide valuable information on AsA content variation in PCA and PCNA persimmon. Persimmon fruit is rich in ascorbic acid; the AsA content of the four varieties 'Zhongshi5', 'Huojing', 'Jiro', and 'Youhou' mature fruit reached 104.49, 48.69, 69.69, and 47.48 mg/100 g. Fruit of the same astringency type persimmon showed a similar AsA accumulation pattern. AsA content was significantly higher in PCA than PCNA fruit at S1-S3. The initial KEGG analysis of metabolites showed that galactose metabolism is the major biosynthetic pathway of AsA in persimmon fruit. There were significant differences in galactose pathway-related metabolite content in developing PCA and PCNA fruit, such as Lactose, D-Tagatose, and D-Sorbitol content in PCA being higher than that of PCNA. Combined gene expression and WGCNA analyses showed that the expression of the GME (evm.TU.contig4144.37) gene was higher in PCA-type than in PCNA-type fruit in S1-S3 and exhibited the highest correlation with AsA content (r = 690 **, p < 0.01). Four hub genes, including the DNA methylation gene, methyltransferase gene, F-box, and Actin-like Protein, were identified as potential regulators of the GME gene. These results provide basic information on how astringency types affect AsA accumulation and will provide valuable information for further investigation on AsA content variation in persimmon fruit.

The Effect of Phosphorus Fertilization on Transcriptome Expression Profile during Lentil Pod and Seed Development

Seed coat hardness and water permeability, which are determined by the accumulation of tannins through the phenylpropanoid pathway in the seed, are important lentil quality characteristics. The impact of seeds’ developmental stage and phosphorus (P) fertilization levels on tannin accumulation is still under research. Through RNA sequencing, this study explored the effect of three P treatments (P0, 6 mg kg−1; P1, 15 mg kg−1; and P2, 21 mg kg−1) and three seed maturity stages (S1, immature 2 mm seed in a flat pod; S2, fully developed seed within the pod; and S3, mature seed at the beginning of the pod’s discoloration) on lentil gene expression. The key findings highlighted a significant influence of the seed maturity stage on phenylpropanoid genes, with S1 displaying the highest expression levels, and on phosphorus-related Gene Ontology (GO) terms that presented the highest number of downregulated genes in the S3 to S1 comparison. P exhibited a targeted effect on the flavanone 3-hydroxylase (F3H) and flavonol synthase (FLS) genes and specific gene clusters, as shown by the differential gene expression analysis. This study investigates the molecular mechanisms related to phosphorus fertilization and seed maturity stages that influence tannin accumulation, offering valuable information for the enhancement of lentil product quality through breeding programs.

Callus Induction and Bioactive Compounds Production from Various Cultivars of Medicago sativa L. (alfalfa)

Alfalfa (Medicago sativa L.) belongs to fabacaea family widely grown in Turkey. It is rich in bioactive compounds such as phenolic compounds, flavonoid, essential amino acids (threonine, leucine, lysine, and valine) and tannins, vitamins (A, B1, B2, B6, B12, C and E) or β-carotene. In this study, it was aimed to investigate the impact of secondary metabolite content of explants on callus biomass. For this purpose, cotyledon explants were obtained under sterile conditions, and transferred to standard MS medium containing 1 mg/L 2,4-D (Dichlorophenoxy Acetic Acid) and 0.0125 mg/L kinetin to induce callus formation. The phenolic, flavonoid and tannin contents of the explants were also determined. Leaves and cotyledons explants of 74 M. sativa L. cultivars have been used for callus biomass. The 74 tested alfalfa cultivars varied in their callus growth and callus biomass formation. Van-22, Konya-Ereğli, Alsancak, Gözlü-1 and Iside cultivars were observed with higher callus biomass: Conversely, Van Gevaş, Bitlis Hizan and Van-Çaldıran responded with lower callus biomass in tissue culture. A high-callus biomass cultivar of alfalfa has been shown to have higher total phenolic, flavonoid and tannin content activity than the lower-callus biomass cultivar in terms of leaf explants under tissue culture conditions. Total phenolic content activity was significantly increased in cotyledon explants with higher callus biomass as compared to lower callus biomass. The accumulation of leaf tannin and flavonoid was strongly linked to callus biomass. Cotyledon phenolic and flavonoid content exhibited an increasing trend in response to the increasing biomass of callus.

Phytochemical Profile and Acute Toxicity of Meistera aculeata (Roxb). Skornick. &amp; M.F. Newman Fruits (Zingiberaceae)

Meistera aculeata (Roxb). Skornick. &amp; M.F. Newman belongs to the ginger family (Zingiberaceae) and locally known as ‘Susube’ by natives of Konawe district of Southeast Sulawesi. M. aculeata is an endemic plant and its fruit has been consumed by the locals. Until today, study on chemistry and biological activity aspects of M. aculeata has yet investigated. Hence, this research aimed to identify phytochemical contents and acute toxicity of M. aculeata fruits extracted using ethanol as the solvent. Phytochemical screening showed the accumulation of alkaloids, tannins, flavonoids, terpenoids, and saponins in the ethanol extract of M. aculeata fruits. Meanwhile, the Brine Shrimp Lethality Test (BSLT) revealed that ethanol extract of M. aculeata fruits has a weak acute toxicity (LC50 683,9 ppm) when compared with potassium dichromate as the positive control of the assay (LC50 8,3 ppm). The study concluded that M. aculeata fruits could be used in the development of drugs from natural sources.

UV-B Radiation Induced the Changes in the Amount of Amino Acids, Phenolics and Aroma Compounds in Vitis vinifera cv. Pinot Noir Berry under Field Conditions.

High UV-B radiation can challenge Pinot noir growth in the wine-making region of the Southern Hemisphere. The aim of this work was to determine UV-B effects on amino acids, phenolic composition and aroma compounds of Pinot noir fruit. Sunlight exposure with or without UV-B did not affect fruit production capacity, °Brix and total amino acids in the vineyard over the two years. This research reported increased contents of skin anthocyanin and skin total phenolics in berry skins under UV-B. The research showed that there were no changes in C6 compounds. Some monoterpenes concentrations were decreased by UV-B. The information also indicated how important leaf canopy management was for vineyard management. Therefore, UV radiation potentially affected fruit ripeness and crop load, and even stimulated the accumulation of phenolic compounds that may affect Pinot noir quality. This research reported that canopy management (UV-B exposure) may be a good way for vineyard management to increase the accumulation of anthocyanins and tannins in berry skins.

Differential tissue-specific accumulation and function of tocochromanols in grape berries

Grape berries have been extensively studied in terms of antioxidant characterization, specifically in anthocyanin, total phenol, and tannin accumulation. However, very little is known about vitamin E composition and contents in this fruit. Aiming to examine the function of vitamin E during grape berries ripening, tocochromanol contents and composition were evaluated in berries and leaves of grapevines (Vitis vinifera L. cv. Merlot), from just before veraison to commercial harvest. We also determined the time-course evolution of tocochromanol accumulation in various fruit tissues, including the skin, pulp, and seeds, and measured the extent of primary and secondary lipid peroxidation, as well as fruit technological maturity parameters. Vitamin E accumulated at higher levels in leaves than in fruits, although the tissue-specific evaluation of tocochromanol contents revealed that berry skin is also rich in α-tocopherol whereas tocotrienols were present in seeds only. α-Tocopherol content decreased during ripening, more specifically in the skin, and it was accompanied by an increase in the extent of lipid peroxidation. Contents and variations in the levels of α-tocopherol, but not those of the other tocochromanols, were inversely related to changes in lipid peroxidation during fruit ripening, as indicated by tissue-specific variations in malondialdehyde contents. In conclusion, α-tocopherol is more abundant in leaves than fruit, yet it apears to exert a role in the modulation of the extent of lipid peroxidation in grape berries, more specifically in the skin, where α-tocopherol depletion and malondialdehyde accumulation may be related to an adequate progression of fruit ripening.

RESEARCH OF THE STATE OF WOODY AND BRUSHWOOD PLANTS UNDER ANTHROPOGENIC STRESS CONDITIONS

Objective. The study of anthropogenic impact on environmental components, primarily on woody and shrub plants, which are the main medium-forming element in natural and artificial ecosystems, is relevant. The subject of this study was the ecological and biological state of plants under conditions of technogenic stress.&#x0D; Materials and methods. The article presents the results of a study of the life state of woody plants. For this, test plots were laid on the territory of sanitary protection zones of industrial enterprises and in the plantings of main plantings. The quantitative content of tannins and polyphenol oxidase in plant leaves during the active growing season was determined by spectrophotometry and titrimetric analysis.&#x0D; Results. Vitality decreases in the following order: Betula pendula Roth.&gt; Sorbus aucuparia L.&gt; Rosa majalis Herrn.&gt; Acer negundo L.&gt; Tilia cordata Mill. In plantations of technogenic territories, an increase in damage to the leaf blade is noted, a greater number of dry branches appear in the crown of a tree, compared to the control zone. Thus, in the study area, the lowest life state scores were recorded in Tilia cordata Mill., And the highest vital state scores were recorded in silver birch. In mountain ash, wild rose and American maple, the vital state is average. The increase in the activity of polyphenol oxidase was observed in plantations of technogenic territories, which is a consequence of intensive anthropogenic load on woody plants. Increased activity of polyphenol oxidase helps to decrease the content of tannins in plant leaves. Betula pendula Roth. Sorbus aucuparia L. in the SPZ of industrial enterprises in July, the accumulation of tannins is more intense than in the control plantations.&#x0D; Conclusion. Betula pendula Roth., Sorbus aucuparia L. in the SPZ of industrial enterprises in July, the accumulation of tannins is more intense than in the control plantations. Spectrophotometric determination of activity helps to understand the reasons why the content of tannins increases or decreases. This fact indicates the participation of tannins in the complex of adaptive reactions of plants, which are associated with protection from aerogenic pollutants. As a result of the study, the most resistant to anthropogenic stress plant species were identified: silver birch, cinnamon rose, and rowan tree.

Effect of foliar treatment with chitosan on phenolic composition of ῾Fetească neagră’ grapes and wines

The objective of this study was to determine the influence of chitosan treatments, applied in vineyard for plan protection, on the phenolic quality of grapes. The study was conducted for two consecutive years (2020-2021) in the wine center of Murfatlar, Romania, on ‘Fetească neagră’, an ancient but well-known indigenous Romanian grape variety for red wines. Chitosan is meant to offer an alternative for the classic treatment with Bordeaux mixture (BM), which represented the control variant. A combination treatment with half dose of chitosan and half dose of BM was also applied and evaluated. Chemical composition at harvest time was evaluated by measuring the content of sugar, total acidity, pH, total anthocyanin potential (ApH1), anthocyanins extractable at wine pH (ApH3.2), total polyphenol index, skin tannins, seed tannins and seeds maturity. In wines the colour parameters were determined by spectrophotometry and individual phenolic compounds by UHPLC-HRMS. In grapes, accumulation of anthocyanins increased with the total dose of chitosan applied in the vineyard, with higher values in 2020 when temperatures were higher and the rainfall values were typical for the region. Accumulation of tannins in grape skins followed a similar trend. In wine, chitosan determined a significant 72% increase in colour intensity in 2020. Among the individual phenols gallic acid was predominant, with higher values in the rainier year (2021) and significant increases determined by chitosan treatment (especially in 2021 when it increased by 97% as compared to BM treatment). Catechin and epicatechin recorded important increases in the less favourable year (2021), with confirmed increases in both years elicited by the chitosan. Quercetin and myricetin were not influenced by the chitosan treatment, but their increase was correlated with higher temperatures and inversely correlated to the amount of rainfall. Trans-resveratrol ranged between 4.3-8.0 mg L-1 in 2020 and 5.0-6.5 mg L-1 in 2021, with an important increase determined by the chitosan treatment in 2020 (89% increase compared to BM treatment).

Cytogenetic Characterization and Metabolomic Differences of Full-Sib Progenies of Saccharum spp.

Sugarcane smut is a worldwide fungal disease. Disease resistance breeding is the most economical and effective measure to prevent and control sugarcane smut. The cytogenetic characteristics and metabolomic differences of sugarcane F1s are closely related to disease resistance. Zhongzhe 1 and G160 sugarcane from the same parents (ROC25 and Yunzhe89-7) were used; the plants were grown in accordance with the barrel method. When the seedlings had 4-5 leaves, genomic in situ hybridization (GISH) was performed; digoxigenin (DIG)-labeled female parental (ROC25)DNA and biotin-labeled male parental (Yunzhe89-7) DNA were used as probes, and the karyotypes of two hybrids were analyzed. The new sugarcane smut-resistant variety (Zhongzhe 1) and the susceptible variety (G160) derived from the same parent were analyzed via gas chromatography-mass spectrometry technology (GC-MS) to compare the metabolomic differences between them. GISH analysis revealed that the chromosome ploidy number of Zhongzhe 1 sugarcane and G160 sugarcane were 114 and 110, respectively. However, the two contain different numbers of chromosomes from the female (ROC25) and male (Yunzhe89-7) parents. Moreover, 258 significantly changed metabolites were identified in smut-resistant Zhongzhe 1, as compared with the smut-susceptible G160 sugarcane: 56 flavonoids, 52 phenolic acids, 30 lipids, 26 organic acids, 26 amino acids and derivatives, 19 nucleotides and derivatives, 5 alkaloids, 9 terpenoids, and 35 others. Multivariate statistical analysis revealed a distinct difference in metabolic pathways between Zhongzhe 1 sugarcane and G160, and both of these varieties had unique functional metabolites. Differences in chromosome composition may constitute the genetic basis for the difference in resistance to smut disease between Zhongzhe 1 sugarcane and G160 sugarcane, and a high accumulation of flavonoids, lipids, terpenoids and tannins may constitute the basis of resistance to smut disease for the Zhongzhe 1 variety.

The D165H Polymorphism of QiMYB-like-1 Is Linked to Interactions between Tannin Accumulation, Herbivory and Biogeographical Determinants of Quercus ilex.

The accumulation in the leaves and young stems of phenolic compounds, such as hydrolyzable and condensed tannins, constitutes a defense mechanism of plants against herbivores. Among other stressing factors, chronic herbivory endangers Quercus ilex, a tree playing a central role in Mediterranean forests. This work addressed the connections between the chemical defenses of Q. ilex leaves and their susceptibility to herbivory, quantitative traits whose relationships are modulated by environmental and genetic factors that could be useful as molecular markers for the selection of plants with improved fitness. A search for natural variants detected the polymorphism D165H in the effector domain of QiMYB-like-1, a TT2-like transcription factor whose family includes members that control the late steps of condensed tannins biosynthesis in different plant species. QiMYB-like-1 D165H polymorphism was screened by PCR-RFLP in trees from six national parks in Spain where Q. ilex has a relevant presence, revealing that, unlike most regions that match the Hardy-Weinberg equilibrium, homozygous plants are over-represented in "Monfragüe" and "Cabañeros", among the best examples to represent the continental Mediterranean (cM) ecosystem. Accordingly, the averages of two stress-related quantitative traits measured in leaves, herbivory index and accumulation of condensed tannins, showed asymmetric distributions depending on the clustering of trees based on ecological and genetic factors. Thus, the impact of herbivory was greater in managed forests with a low density of trees from the cM region, among which QiMYB-like-1 D165 homozygotes stand out, whereas condensed tannins accumulation was higher in leaves of QiMYB-like-1 H165 homozygotes from low-density forests, mainly in the Pyrenean (Py) region. Besides, the correlation between the contents of condensed tannins and total tannins vanished after clustering by the same factors: the cM region singularity, forest tree density, and QiMYB-like-1 genotype, among which homozygous shared the lowest link. The biogeographical and genetic constraints that modulate the contribution of condensed tannins to chemical defenses also mediated their interactions with the herbivory index, which was found positively correlated with total phenolics or tannins, suggesting an induction signal by this biotic stress. In contrast, a negative correlation was observed with condensed tannins after tree clustering by genetics factors where associations between tannins were lost. Therefore, condensed tannins might protect Q. ilex from defoliation in parks belonging to the cM ecosystem and carrying genetic factor(s) linked to the QiMYB-like-1 D165H polymorphism.

Widely targeted metabolite profiling of mango stem apex during floral induction by compond of mepiquat chloride, prohexadione-calcium and uniconazole.

Insufficient low temperatures in winter and soil residues caused by paclobutrazol (PBZ) application pose a considerable challenge for mango floral induction (FI). Gibberellin inhibitors SPD (compound of mepiquat chloride, prohexadione-calcium and uniconazole) had a significant influence on enhancing the flowering rate and yield of mango for two consecutive years (2020-2021). Researchers have indicated that FI is regulated at the metabolic level; however, little is known about the metabolic changes during FI in response to SPD treatment. Here, ultra-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS)-based widely targeted metabolomic analysis was carried out to assess the metabolic differences in the mango stem apex during different stage of mango FI (30, 80, 100 days after SPD/water treatment). A total of 582 compounds were annotated and 372 metabolites showed two-fold differences in abundance (variable importance in projection, VIP ≥ 1 and fold change, FC≥ 2 or≤ 0.5) between buds at 30, 80, 100 days after SPD/water treatment or between buds under different treatment. Lipids, phenolic acids, amino acids, carbohydrates, and vitamins were among metabolites showing significant differences over time after SPD treatment. Here, 18 out of 20 lipids, including the lysophosphatidylethanolamine (12, LPE), lysophosphatidylcholine (7, LPC), and free fatty acids (1, FA), were significantly upregulated from 80 to 100 days after SPD treatment comared to water treatment. Meanwhile, the dormancy release of mango buds from 80 to 100 days after SPD treatment was accompanied by the accumulation of proline, ascorbic acid, carbohydrates, and tannins. In addition, metabolites, such as L-homocysteine, L-histidine, and L-homomethionine, showed more than a ten-fold difference in relative abundance from 30 to 100 days after SPD treatment, however, there were no significant changes after water treatment. The present study reveals novel metabolites involved in mango FI in response to SPD, which would provide a theoretical basis for utilizing SPD to induce mango flowering.

Differential Responses of Dominant Plants to Grazing in Typical Temperate Grassland in Inner Mongolia

Leymus chinensis, Stipa grandis, Artemisia frigida, and Cleistogenes squarrosa are the dominant plant species in typical temperate grasslands in Xilingol. Intensive studies related to overgrazing, which resulted in a dominant plant shift, have been carried out in recent years, but the ways in which these four species respond to different grazing intensities remain elusive. In this study, the contents of primary metabolites, secondary metabolites, and phytohormones in the leaves of these species under five grazing intensities were assayed and compared. The results showed that A. frigida contained higher amounts of lignin, while C. squarrosa contained higher amounts of total flavonoids than the other species. Leymus chinensis showed a different accumulation of cellulose and tannin in response to grazing, compared with the other three species. Stipa grandis and A. frigida increased in soluble protein contents in response to different grazing treatments. In particular, the contents of phytohormones, such as abscisic acid, salicylic acid, and gibberellins, were markedly changed under grazing. Leymus chinensis exhibited different abscisic acid and gibberellins accumulation patterns compared with the other species, under the different grazing intensities. Patterns of salicylic acid accumulation were similar (except under light and moderate grazing intensities in A. frigida) among the four species. The results indicated that the four species differed in adaptive strategies to cope with the different grazing intensities, and phytohormones played important roles in coordinating the regulation of their growth and grazing tolerance. This study provides a foundation for elucidating the mechanisms of overgrazing-induced degradation of the Xilingol grassland.

Widely targeted metabolomics reveals stamen petaloid tissue of Paeonia lactiflora Pall. being a potential pharmacological resource.

Paeonia lactiflflora Pall. has a long edible and medicinal history because of the very high content of biologically active compounds. However, little information is available about the metabolic basis of pharmacological values of P. lactiflora flowers. In this study, we investigated metabolites in the different parts of P. lactiflora flowers, including petal, stamen petaloid tissue and stamen, by widely targeted metabolomics approach. A total of 1102 metabolites were identified, among which 313 and 410 metabolites showed differential accumulation in comparison groups of petal vs. stamen petaloid tissue and stamen vs. stamen petaloid tissue. Differential accumulated metabolites analysis and KEGG pathway analysis showed that the flavonoids were the most critical differential metabolites. Furthermore, difference accumulation of flavonoids, phenolic acids, tannins and alkaloids might lead to the differences in antioxidant activities and tyrosinase inhibition effects. Indeed, stamen petaloid tissue displayed better antioxidant and anti-melanin production activities than petal and stamen through experimental verification. These results not only expand our understanding of metabolites in P. lactiflora flowers, but also reveal that the stamen petaloid tissues of P. lactiflora hold the great potential as promising ingredients for pharmaceuticals, functional foods and skincare products.

Characterization of browning during CO2 deastringency treatment in astringent persimmon fruit

Deastringency treatment with CO2 is an effective and convenient method for improving the marketability of persimmon fruit. However, the main persimmon cultivars in China turn brown very quickly following exposure to a high-CO2 atmosphere, causing significant economic loss. However, the mechanisms of persimmon browning under CO2 treatment remain largely unknown. In this study, we evaluated components and enzymes related to persimmon fruit browning. The results revealed that astringency was alleviated by simultaneous reduction of soluble tannin content and accumulation of insoluble tannin. During persimmon browning, fruit firmness, total phenolic content, and phenylalanine ammonia lyase (PAL) activity decreased significantly, whereas malondialdehyde (MDA), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and polyphenol oxidase (PPO) activity increased significantly, suggesting that reactive oxygen species (ROS)-scavenging enzymes and non-enzymatic antioxidants cannot effectively maintain redox reaction balance to protect cell membranes from oxidative damage during CO2 treatment. An untargeted metabolomics analysis identified 19 polyhydroxyphenols that were downregulated in CO2-treated fruit, suggesting that phenolics may act as a substrate for persimmon browning. We also identified 11 metabolites associated with abiotic stress. Together, these results study provide valuable information on the mechanism of persimmon fruit browning induced by CO2 treatment and will contribute to the ongoing development of the persimmon fruit industry.