Explore the interaction between root metabolism and rhizosphere microbiota during the growth of Angelica sinensis.

Angelica sinensis is a medicinal plant widely used to treat multiple diseases in Asia and Europe, which contains numerous active components with therapeutic value. The interaction between root and rhizosphere microorganisms is crucial for the growth and quality formation of medicinal plants. But the micro-plant-metabolite regulation patterns for A. sinensis remain largely undetermined. Here, we collected roots and rhizosphere soils from A. sinensis in seedling stage (M) and picking stage (G), respectively cultivated for one year and two years, generated metabolite for roots, microbiota data for rhizospheres, and conducted a comprehensive analysis. Changes in metabolic and microbial communities of A.sinensis over growth were distinct. The composition of rhizosphere microbes in G was dominated by proteobacteria, which had a strong correlation with the synthesis of organic acids, while in M was dominated by Actinobacteria, which had a strong correlation with the synthesis of phthalide and other organoheterocyclic compounds, flavonoids, amines, and fatty acid. Additionally, co-occurrence network analysis identified that Arthrobacter was found to be strongly correlated with the accumulation of senkyunolide A and n-butylidenephthalide. JGI 0001001.H03 was found to be strongly correlated with the accumulation of chlorogenic acid. Based on rhizosphere microorganisms, this study investigated the correlation between root metabolism and rhizosphere microbiota of A. sinensis at different growth stages in traditional geoherb region, which could provide references for exploring the quality formation mechanism of A. sinensis in the future.

GABA shunt contribution to flavonoid biosynthesis and metabolism in tea plants (Camellia sinensis).

γ-Aminobutyric acid (GABA), a signal molecule, is regarded as the intersection node of carbon and nitrogen metabolism, and its contributions to flavonoid metabolism in tea plant growth and development remain unclear. The correlation between the GABA shunt and flavonoid metabolism in tea plants is worth to explore. Secondary metabolites and their correlations with the taste of tea soup made from tea plants (Camellia sinensis) during different seasons were investigated. Related secondary metabolites and transcript profiles of genes encoding enzymes in the GABA shunt, flavonoid pathway and polyamine biosynthesis were measured throughout the tea plant growth seasons and after exogenous GABA applications. In addition, the abundance of differentially expressed proteins was quantified after treatments with or without exogenous GABA. The tea leaves showed the highest metabolite concentrations in spring season. CsGAD, CsGABAT, CsSPMS, CsODC, CsF3H and CsCHS were found to be important genes in the GABA and anthocyanin biosynthesis pathways. GABA and anthocyanin concentrations showed a positive correlation, to some extent, CsF3H and CsCHS played important roles in the GABA and anthocyanin biosynthesis.

Total Tocopherols, Carotenoids, and Fatty Acids Content Variation of Pistacia atlantica from Different Organs' Crude Oils and Their Antioxidant Activity during Development Stages.

The current study investigated the effect of developmental stages on the chemical composition and the antioxidant activity of fifteen crude oil samples obtained from Pistacia atlantica Desf. leaves, galls, and fruits. Twelve fatty acids were detected by GC/FID, linolenic acid (C18 : 3) was the major fatty acid detected in leaves crude oils that registered [41.73 % (P<0.05)] on the last stage. The best content of tocopherols and carotenoids was recorded at the last stage for leaves and galls oils, respectively, with values of [1.530±0.01, 0.52±0.01 (P<0.05) mg α-tocopherol equivalent/g DW] and [86.60±0.95, 69.15±0.13 (P<0.05) µg ß-carotene equivalent/g DW]. For fruits oils, the content varied depending on the levels of fruits maturation. The results from DPPH, FRAP, and ABTS assays revealed that the antioxidant activity increased with the increasing content of tocopherols and carotenoids in leaves and galls oils during development stages, and varied for fruits oils depending on the ripening stages. Moreover, according to PCA analysis, the best phytoconstituent content and antioxidant activity were attributed to P. atlantica Desf. fruit's crude oils. Also, a strong relationship was found between the antioxidant activity and bioactive phytochemical components, such as tocopherols, carotenoids, and omega-three fatty acid, which confirmed that P. atlantica Desf. crude oils present a valuable source of natural antioxidant that could be used for pharmaceutical and food industries purposes.

Harvest Strategies for Optimization of the Content of Bioactive Alkamides and Caffeic Acid Derivatives in Aerial Parts and in Roots of Echinacea purpurea.

Aerial parts and roots of Echinacea purpurea were harvested consecutively in order to find the best strategy for harvest of both types of plant material for an optimal content of bioactive alkamides and caffeic acid derivatives. Four caffeic acid derivatives and 15 alkamides were identified and quantified. The aerial parts were harvested in bud, bloom, and wilting stage and the roots were harvested 1 week, 1 month, and 3 months after each harvest of aerial parts. The highest yield per area of both alkamides and caffeic acid derivatives is achieved when the aerial parts are harvested late (wilting stage). To obtain an optimal content of alkamides and caffeic acid derivatives it is not recommendable to harvest the aerial parts and the roots in the same year. If the aerial parts must be harvested, the roots should be harvested 1 week after because this will result in the most optimal concentration of bioactive compounds in both products.

A PPO Promoter from Betalain-Producing Red Swiss Chard, Directs Petiole- and Root-Preferential Expression of Foreign Gene in Anthocyanins-Producing Plants.

A 1670 bp 5'-flanking region of the polyphenol oxidase (PPO) gene was isolated from red Swiss chard, a betalain-producing plant. This region, named promoter BvcPPOP, and its 5'-truncated versions were fused with the GUS gene and introduced into Arabidopsis, an anthocyanins-producing plant. GUS histochemical staining and quantitative analysis of transgenic plants at the vegetative and reproductive stages showed that BvcPPOP could direct GUS gene expression in vegetative organs with root- and petiole-preference, but not in reproductive organs including inflorescences shoot, inflorescences leaf, flower, pod and seed. This promoter was regulated by developmental stages in its driving strength, but not in expression pattern. It was also regulated by the abiotic stressors tested, positively by salicylic acid (SA) and methyl jasmonate (MeJA) but negatively by abscisic acid (ABA), gibberellin (GA), NaCl and OH(-). Its four 5'-truncated versions varied in the driving strength, but not obviously in expression pattern, and even the shortest version (-225 to +22) retained the root- and petiole- preference. This promoter is, to our knowledge, the first PPO promoter cloned and functionally elucidated from the betalain-producing plant, and thus provides not only a useful tool for expressing gene(s) of agricultural interest in vegetative organs, but also a clue to clarify the function of metabolism-specific PPO in betalain biosynthesis.

Metabolomic Characterization of Hot Pepper (Capsicum annuum "CM334") during Fruit Development.

Non-targeted metabolomic analysis of hot pepper (Capsicum annuum "CM334") was performed at six development stages [16, 25, 36, 38, 43, and 48 days post-anthesis (DPA)] to analyze biochemical changes. Distinct distribution patterns were observed in the changes of metabolites, gene expressions, and antioxidant activities by early (16-25 DPA), breaker (36-38 DPA), and later (43-48 DPA) stages. In the early stages, glycosides of luteolin, apigenin, and quercetin, shikimic acid, γ-aminobutyric acid (GABA), and putrescine were highly distributed but gradually decreased over the breaker stage. At later stages, leucine, isoleucine, proline, phenylalanine, capsaicin, dihydrocapsaicin, and kaempferol glycosides were significantly increased. Pathway analysis revealed metabolite-gene interactions in the biosynthesis of amino acids, capsaicinoids, fatty acid chains, and flavonoids. The changes in antioxidant activity were highly reflective of alterations in metabolites. The present study could provide useful information about nutrient content at each stage of pepper cultivation.