Hongxia Cui

This study aimed to investigate the potential effects of OEO on production performance, egg quality, fatty acid composition in yolk, and cecum microbiota of hens in the late phase of production. A total of 350 58-week-old Jing Tint Six laying hens were randomly divided into five groups: (1) fed a basal diet (control); (2) fed a basal diet + 5 mg/kg flavomycin (AGP); (3) fed a basal diet + 100 mg/kg oregano essential oil + 20 mg/kg cinnamaldehyde (EO1); (4) fed a basal diet + 200 mg/kg oregano essential oil + 20 mg/kg cinnamaldehyde (EO2); (5) fed a basal diet + 300 mg/kg oregano essential oil + 20 mg/kg cinnamaldehyde (EO3). Compared to the control group, group EO2 exhibited higher (p < 0.05) egg production during weeks 5–8 and 1–8. EO2 had a lower feed conversion ratio than the control group during weeks 1–8. The content of monounsaturated fatty acid (MUFA) in EO2 was higher (p < 0.05) than that of the control and AGP groups. EO2 increased (p < 0.05) the abundance of Actinobacteriota and decreased the abundance of Desulfovibri in the cecum. The abundances of Anaerofilum, Fournierella, Fusobacterium, and Sutterella were positively correlated with egg production, feed conversion ratio, and average daily feed intake, while the abundances of Bacteroides, Desulfovibrio, Lactobacillus, Methanobrevibacter, and Rikenellaceae_RC9_gut_group were negatively correlated with egg production, feed conversion ratio, and average daily feed intake. Dietary supplementation with 200 mg/kg OEO and 20 mg/kg cinnamaldehyde could improve egg-production performance, decrease feed conversion ratio, and alter the fatty acid and microbial composition of eggs from late-phase laying hens.

Origanum vulgare, belonging to the Lamiaceae family, is a principal culinary herb used worldwide which possesses great antioxidant and antibacterial properties corresponding to various volatile organic components (VOCs). However, the metabolite profiles and underlying biosynthesis mechanisms of elaborate tissues (stems, leaves, bracts, sepals, petals) of Origanum vulgare have seldom been reported. Here, solid-phase microextraction–gas chromatography/mass spectrometry results showed that Origanum vulgare ‘Hot and Spicy’ (O. vulgare ‘HS’) was extremely rich in carvacrol and had the tissue dependence characteristic. Moreover, a full-length transcriptome analysis revealed carvacrol biosynthesis and its tissue-specific expression patterns of ‘upstream’ MVA/MEP pathway genes and ‘downstream’ modifier genes of TPSs, CYPs, and SDRs. Furthermore, the systems biology method of modular organization analysis was applied to cluster 16,341 differently expressed genes into nine modules and to identify significant carvacrol- and peltate glandular trichome-correlated modules. In terms of these positive and negative modules, weighted gene co-expression network analysis results showed that carvacrol biosynthetic pathway genes are highly co-expressed with TF genes, such as ZIPs and bHLHs, indicating their involvement in regulating the biosynthesis of carvacrol. Our findings shed light on the tissue specificity of VOC accumulation in O. vulgare ‘HS’ and identified key candidate genes for carvacrol biosynthesis, which would allow metabolic engineering and breeding of Origanum cultivars.

SUMMARY: Lilacs (Syringa L.), a group of well‐known ornamental and aromatic woody plants, have long been used for gardening, essential oils and medicine purposes in East Asia and Europe. The lack of knowledge about the complete genome of Syringa not only hampers effort to better understand its evolutionary history, but also prevents genome‐based functional gene mining that can help in the variety improvement and medicine development. Here, a chromosome‐level genome of Syringa oblata is presented, which has a size of 1.12 Gb including 53 944 protein coding genes. Synteny analysis revealed that a recent duplication event and parallel evolution of two subgenomes formed the current karyotype. Evolutionary analysis, transcriptomics and metabolic profiling showed that segment and tandem duplications contributed to scent formation in the woody aromatic species. Moreover, phylogenetic analysis indicated that S. oblata shared a common ancestor with Osmanthus fragrans and Olea europaea approximately 27.61 million years ago (Mya). Biogeographic reconstruction based on a resequenced data set of 26 species suggested that Syringa originated in the northern part of East Asia during the Miocene (approximately 14.73 Mya) and that the five Syringa groups initially formed before the Late Miocene (approximately 9.97 Mya). Furthermore, multidirectional dispersals accompanied by gene introgression among Syringa species from Northern China during the Miocene were detected by biogeographic reconstruction. Taken together, the results showed that complex gene introgression, which occurred during speciation history, greatly contributed to Syringa diversity.

The use of antibiotics in the food industry is highly regulated owing to the potential harmful effects of antibiotics on human health. Therefore, it is crucial to seek alternatives for ensuring food safety. Essential oils (EOs) extracted from plants of the genus Origanum exhibit a wide range of chemical and antibacterial activities. Species and tissue factors shape the production and accumulation processes of EOs in Origanum plants, thereby affecting their bactericidal activity. In this study, the morphologies and EO yields from the inflorescences, leaves, and stems of three oregano cultivars were evaluated. In addition, the chemical compositions and antibacterial abilities of oregano EOs (OEOs) were assessed. The results showed that OEOs from the different parts of the plant displayed only minor differences in chemical composition, whereas the yield of EOs varied considerably. Additionally, the chemical profiles of OEOs differed significantly among cultivars. The carvacrol content in the OEOs was closely related to its activity against Staphylococcus aureus; the antibacterial properties of the OEOs were further verified using carvacrol. These findings suggested that OEOs possessing high antibacterial activity may have the potential to be developed as bactericides in the food industry.

Essential oils (EOs) of Lavandula angustifolia, mainly consist of monoterpenoids and sesquiterpenoids, are of great commercial value. The multi-flower spiciform thyrse of lavender not only determines the output of EOs but also reflects an environmental adaption strategy. With the flower development and blossom in turn, the fluctuation of the volatile terpenoids displayed a regular change at each axis. However, the molecular mechanism underlying the regulation of volatile terpenoids during the process of flowering is poorly understood in lavender. Here, we combine metabolite and RNA-Seq analyses of flowers of five developmental stages at first- and second-axis (FFDSFSA) and initial flower bud (FB0) to discover the active terpenoid biosynthesis as well as flowering-related genes. A total of 56 mono- and sesquiterpenoids were identified in the EOs of L. angustifolia ‘JX-2’. FB0’ EO consists of 55 compounds and the two highest compounds, β-trans-ocimene (20.57%) and (+)-R-limonene (17.00%), can get rid of 74.71 and 78.41% aphids in Y-tube olfactometer experiments, respectively. With sequential and successive blossoms, temporally regulated volatiles were linked to pollinator attraction in field and olfaction bioassays. In three characteristic compounds of FFDSFSA’ EOs, linalyl acetate (72.73%) and lavandulyl acetate (72.09%) attracted more bees than linalool (45.35%). Many transcripts related to flowering time and volatile terpenoid metabolism expressed differently during the flower development. Similar metabolic and transcriptomic profiles were observed when florets from the two axes were maintained at the same maturity grade. Besides both compounds and differentially expressed genes were rich in FB0, most volatile compounds were significantly correlated with FB0-specific gene module. Most key regulators related to flowering and terpenoid metabolism were interconnected in the subnetwork of FB0-specific module, suggesting the cross-talk between the two biological processes to some degree. Characteristic compounds and gene expression profile of FB0 exhibit ecological value in pest control. The precise control of each-axis flowering and regular emissions at transcriptional and metabolic level are important to pollinators attraction for lavender. Our study sheds new light on lavender maximizes its fitness from “gene-volatile terpenoid-insect” three layers.