Search

Plant essential oils contain abundant natural active compounds, mainly terpenes and phenylpropanes, with immense industrial and pharmaceutical applications. The opposite variations between sesquiterpenes and phenylpropanes are widespread, determining the application and value of essential oils. However, intricate regulatory mechanisms at the molecular level have not been uncovered. To this end, transcriptome, metabolome, high-performance gas chromatography, exogenous protocatechuic acid and ABA treatments were performed on P. sheareri leaves at different developmental stages. Results revealed that the content of essential oils in the young leaves (2.45 mg/g) was 70.14% higher than in mature ones (1.44 mg/g). Additionally, there were opposing variations in the accumulation of phenylpropanes and sesquiterpenes, which correlated with the differential expression genes (DEGs) enriched in the shikimate pathway, phenylpropanoid biosynthesis and related secondary metabolites pathways in P. sheareri leaves. Phenylpropanes and sesquiterpene profiles presented dynamic patterns that changed with leaf growth and were consistent with the pattern of key gene regulation in the corresponding paths. After the combined multi-omics analysis, structural genes (DHQS , TPS1 , CYP707A2) and possible interacting TFs with the key genes (i.e., SHR , JA2L , WRKY12 , WRKY76 , and ERF113) could be responsible for the opposite relationship between phenylpropanes and sesquiterpenes. Different concentrations treatments of protocatechuic acid and ABA indicated shikimate pathway mediated biosynthesis and metabolism of phenylpropanes and sesquiterpenes in the P. sheareri leaves, in which the downregulated DHQS and CYP707A2 , and upregulated TPS1 and SHR played the vital roles. Based on the identified differentially accumulated phenylpropanes, sesquiterpenes, and candidate hub DEGs, genetic and metabolic regulation mechanisms of secondary metabolites in the essential oils were further proposed, providing a new understanding of essential oils biosynthesis. Potential regulatory factors identified in this study will contribute to providing molecular traces for in-depth research on the relationship of phenylpropanes and sesquiterpenes biosynthesis, as well as product development for essential oils with higher value. [Display omitted] • Young leaves had more essential oils and sesquiterpenes than mature leaves. • Young leaves had fewer phenylpropanes than mature leaves. • DHQS , TPS1 , CYP707A2 , and SHR are candidate core genes. • Protocatechuic acid reduced DHQS expression level while increasing TPS1. • The shikimate pathway mediated the antagonism of phenylpropanes and sesquiterpenes. [ABSTRACT FROM AUTHOR]

MYB transcription factor (TF) genes are crucial for modulating secondary metabolite biosynthesis in plants. Stevia is a valuable economic crop, and the steviol glycosides produced in its leaves are the most prevalent natural sweeteners. The present research offers a thorough genomic examination of Stevia's MYB TF gene superfamily. We identified 310 genes as putative MYB genes, out of which 176 R2R3-MYB genes were chosen for subsequent analysis. A comparative phylogenetic analysis classified these Stevia R2R3-MYB genes into nine subfamilies, with exon-intron structures and motif compositions strongly supporting this classification. Furthermore, due to its significant expansion, subfamily VIII was divided into 17 clades, and clade VIII-E was unique to Stevia. Synteny analysis revealed that the expansion of members in each subfamily, or each clade within subfamily VIII, was mainly facilitated by whole-genome duplication (WGD) as well as dispersed duplication events. Promoter detection identified multiple classes of cis-regulatory elements that are associated with responses to light, phytohormones, and environmental stressors. Expression analysis revealed that different subfamilies or clades of R2R3-MYB genes exhibited diverse expression profiles across multiple tissue types and at various phases of leaf growth. Meanwhile, SrMYB32 , 15 , 114/168, 163 , 125/126 , 33 , 153/154 showed significant expression differences in two Stevia varieties with different steviol glycosides content. The present research lays a firm basis for future functional analysis of R2R3-MYBs that play important roles in the biosynthesis of steviol glycosides. • A systematic analysis of Stevia R2R3-MYB genes was performed, including phylogenetic motif, and synteny analysis. • The expansion of Stevia R2R3-MYB genes was mainly facilitated by whole-genome duplication and dispersed duplication events. • Some R2R3-MYB genes were differentially expressed in Stevia cultivars with different steviol glycoside contents. [ABSTRACT FROM AUTHOR]

Methicillin-resistant Staphylococcus aureus (MRSA) has evolved to tolerate almost all known β-lactam antibiotics, and been exhibiting resistance to vancomycin. Developing new drugs against the MRSA infection are urgently needed. Natural resource is enriched with antimicrobial molecules. Here, we report an extract from leaves of Cyclocarya paliurus (ECPL), a species of tree native to China and being traditionally cultivated as medicinal plant, which shows a broad spectrum of bacteriostatic and bactericidal effects at MIC 50 15.99 ± 0.55 μg/ml against methicillin-susceptible and -resistant S. aureus. The ECPL suppresses bacterial expression of FtsZ at both transcriptional and protein levels, inhibits its GTPase activity, blocks the assembly dynamics of FtsZ, and disrupts the formation of Z-ring. The bacteria cells fail to divide, enlarge initially, and lyse eventually. In mouse model, the ECPL facilitates skin wound healing with MRSA infection as effective as vancomycin. Our study unveils the potential of identifying novel molecule in ECPL for development of new class of antibiotic against both methicillin-susceptible and -resistant S. aureus , and support domestication of the C. paliurus growing from wild to cultivated, and further scale up the cultivation into industrialized farm for sustainable harvest for pharmaceutic interest. [Display omitted] • An extract from Cyclocarya paliurus (ECPL) leaves shows anti-MRSA activity. • The ECPL suppresses bacterial FtsZ at transcriptional and protein levels and eliminates the GTPase enzyme activity. • Bacteria abort Z-ring formation , fail to divide, and die. • This effect bypasses known resistance machineries and shows a potential for new antibiotic development. • Domesticating and scaling up the cultivation will guaranty sustainable harvest for the pharmaceutic interest. [ABSTRACT FROM AUTHOR]

Revealing the dynamic accumulation and synthesizing mechanism of medicinal bioactive products is critical for the evaluation and utilization of crops in medicinal industry. Huangqin (Scutellaria baicalensis Georgi) and Nianmao-Huangqin (Scutellaria viscidula Bge) are important medicinal crops containing flavonoids with good bioactivities. Previous studies have found significant differences of flavonoid contents between the two species. Nevertheless, the dynamic changes of bioactive products and related differential synthesizing mechanism remains unknown. In this study, an inter-specific comparative study was reported on the dynamic accumulation of eight bioactive products (scutellarin, scutellarein, baicalin, wogonoside, apigenin, baicalein, wogonin, and chrysin) and the expression of seven key enzyme genes in different organs (root, stem, and leaf) during different growth stages (May, June, July, August, September, and October) of S. baicalensis and S. viscidula. The results showed that the eight bioactive products were differentially accumulated in different growth stages for the two species. Specifically, the contents of five ingredients (except wogonoside, scutellarein and apigenin) in roots of S. baicalensis were significantly higher than those in S. viscidula in harvest stage (October). Meanwhile, the relative expression of seven key enzyme genes in baicalin synthesizing pathway showed significant spatio-temporal specificities. The expression of UBGAT in downstream baicalin synthesis was significantly higher in roots of S. baicalensis than that of S. viscidula (P < 0.05). Moreover, there exist significant correlations between the content of bioactive products and the expression of key enzyme genes. The expression of upstream (CLL-7 , FNSII-1 , FNSII-2) and downstream (F6H and UBGAT) key enzyme genes were significantly positively correlated with the contents of baicalin in both S. baicalensis and S. viscidula. On the contrary, the expression of GUS was significantly negatively correlated with the content of baicalin in the two species. Collectively, these results give clear evidences that the expression of key enzyme genes (e.g., FNSII-2 , GUS , and UBGAT) in baicalin synthesis is probably the main reason for the difference of bioactive products, suggesting that S. viscidula can be used as an alternative to S. baicalensis in pharmaceutical industry. Furthermore, these findings will provide a theoretical basis for exploring the inter-specific differences of bioactive products in medicinal crops within the same genus, thereby revealing the molecular mechanism of quality formation of Chinese medicinal materials. • Eight bioactive products showed content difference between two Scutellaria crops. • Seven key genes were differentially expressed in S. baicalensis and S. viscidula. • Difference of product content was correlated with difference of gene expression. • S. viscidula can be used as alternative medicinal source to S. baicalensis. • Molecular mechanism of differential bioactive product contents was revealed. [ABSTRACT FROM AUTHOR]