Search Results (6)

Light is an important environmental regulator of plant secondary metabolism. Terpenoids, the most abundant secondary metabolites in plants, demonstrate a wide spectrum of biologically significant properties, encompassing antimicrobial, antioxidative, and analgesic activities. Litsea cubeba (Lour.) Pers., a core species within the Lauraceae family, exhibits notable pharmacological potential, including antimicrobial and antitumor effects. Here, we found that darkness treatment significantly suppressed terpenoid accumulation in L. cubeba fruits. To clarify the molecular mechanisms underlying the regulatory effect of light and darkness treatments on terpenoid biosynthesis, we conducted a comparative transcriptome profiling of L. cubeba fruits under light and darkness treatments. A total of 13,074 differentially expressed genes (DEGs) were identified among four sampling time points (L1-L2-L3-L4 vs. D1-D2-D3-D4). These genes were enriched in various pathways, with significant enrichment being observed in the terpenoid and other secondary metabolism pathways. Additionally, the enrichment of DEGs in L2 and D2 stages was further studied, and it was found that nine DEGs were significantly enriched in the monoterpene synthesis pathway. The weighted gene co-expression network analysis (WGCNA) showed that alcohol dehydrogenase (ADH), a key enzyme in terpenoid synthesis, had the same expression pattern as WRKY and NAC transcription factors, suggesting their involvement in the biosynthesis of terpenoids in L. cubeba. Expression profiling demonstrated that plastid-localized terpenoid pathway genes were markedly downregulated under darkness treatment. qRT-PCR validation of key genes (LcDXS3, LcHMGS1, LcMDS, and LcTPS19) confirmed the reliability of the transcriptome data, with LcDXS3 exhibiting pronounced declines in expression after 6 h (2.76-fold decrease) and 12 h (2.63-fold decrease) of darkness treatment. These findings provide novel insights into the photoregulatory mechanisms governing terpenoid metabolism in L. cubeba. Full article

Oleosins (OLEs) are a class of small but abundant structural proteins that play essential roles in the formation and stabilization of lipid droplets (LDs) in seeds of oil crops. Despite the proposal of five oleosin clades (i.e., U, SL, SH, T, and M) in angiosperms, their evolution in eudicots has not been well-established. In this study, we employed Brassicales, an economically important order of flowering plants possessing the lineage-specific T clade, as an example to address this issue. Three to 10 members were identified from 10 species representing eight plant families, which include Caricaceae, Moringaceae, Akaniaceae, Capparaceae, and Cleomaceae. Evolutionary and reciprocal best hit-based homologous analyses assigned 98 oleosin genes into six clades (i.e., U, SL, SH, M, N, and T) and nine orthogroups (i.e., U1, U2, SL, SH1, SH2, SH3, M, N, and T). The newly identified N clade represents an ancient group that has already appeared in the basal angiosperm Amborella trichopoda, which are constitutively expressed in the tree fruit crop Carica papaya, including pulp and seeds of the fruit. Moreover, similar to Clade N, the previously defined M clade is actually not Lauraceae-specific but an ancient and widely distributed group that diverged before the radiation of angiosperm. Compared with A. trichopoda, lineage-specific expansion of the family in Brassicales was largely contributed by recent whole-genome duplications (WGDs) as well as the ancient γ event shared by all core eudicots. In contrast to the flower-preferential expression of Clade T, transcript profiling revealed an apparent seed/embryo/endosperm-predominant expression pattern of most oleosin genes in Arabidopsis thaliana and C. papaya. Moreover, the structure and expression divergence of paralogous pairs was frequently observed, and a good example is the lineage-specific gain of an intron. These findings provide insights into lineage-specific family evolution in Brassicales, which facilitates further functional studies in nonmodel plants such as C. papaya. Full article

Taxonomy of the genus Cinnamomum Schaeff. (Lauraceae) is difficult because of parallel evolution of morphology. Recent phylogenomic and taxonomic studies have clarified the problem and subdivided the Asian Cinnamomum into two genera, i.e., Camphora Fabr. and Cinnamomum sensu stricto. Here we sequenced and characterized the plastome of a recently described species Cinnamomum guizhouense C.Y. Deng, Zhi Yang et Y. Yang, performed a phylogenomic analysis, and also conducted a comparative analysis. The plastome of Cinnamomum guizhouense is 152,739 bp long and quadri-parted with a pair of inverted repeat regions (IR: 20,132 bp) divided by a small single copy region (SSC: 18,852 bp) and a large single copy region (LSC: 93,623 bp). The plastome possesses a total of 128 genes including 82 protein-coding genes, 36 tRNA genes, and eight rRNA genes, which is similar to most published plastomes of the core Lauraceae group. The plastome of Cinnamomum guizhouense displays higher similarity to Camphora than Cinnamomum. Our phylogenomic result suggests that Cinnamomum guizhouense belongs to the Camphora clade. As a result, we propose a new combination, i.e. Camphora guizhouensis (C.Y. Deng, Zhi Yang et Y. Yang) Zhi Yang et Y.Yang, comb. nov. Full article

Litsea Lam. is an ecological and economic important genus of the “core Lauraceae” group in the Lauraceae. The few studies to date on the comparative chloroplast genomics and phylogenomics of Litsea have been conducted as part of other studies on the Lauraceae. Here, we sequenced the whole chloroplast genome sequence of Litsea auriculata, an endangered tree endemic to eastern China, and compared this with previously published chloroplast genome sequences of 11 other Litsea species. The chloroplast genomes of the 12 Litsea species ranged from 152,132 (L. szemaois) to 154,011 bp (L. garrettii) and exhibited a typical quadripartite structure with conserved genome arrangement and content, with length variations in the inverted repeat regions (IRs). No codon usage preferences were detected within the 30 codons used in the chloroplast genomes, indicating a conserved evolution model for the genus. Ten intergenic spacers (psbE–petL, trnH–psbA, petA–psbJ, ndhF–rpl32, ycf4–cemA, rpl32–trnL, ndhG–ndhI, psbC–trnS, trnE–trnT, and psbM–trnD) and five protein coding genes (ndhD, matK, ccsA, ycf1, and ndhF) were identified as divergence hotspot regions and DNA barcodes of Litsea species. In total, 876 chloroplast microsatellites were located within the 12 chloroplast genomes. Phylogenetic analyses conducted using the 51 additional complete chloroplast genomes of “core Lauraceae” species demonstrated that the 12 Litsea species grouped into four sub-clades within the Laurus-Neolitsea clade, and that Litsea is polyphyletic and closely related to the genera Lindera and Laurus. Our phylogeny strongly supported the monophyly of the following three clades (Laurus–Neolitsea, Cinnamomum–Ocotea, and Machilus–Persea) among the above investigated “core Lauraceae” species. Overall, our study highlighted the taxonomic utility of chloroplast genomes in Litsea, and the genetic markers identified here will facilitate future studies on the evolution, conservation, population genetics, and phylogeography of L. auriculata and other Litsea species. Full article

Lauraceae is a large family of woody plants with high ecological and economic value. The tribal and generic division and phylogenetic relationship of Lauraceae have long been controversial. Based on morphological and molecular evidence, phylogenetic relationships within the Cinnamomeae, Laureae and Perseeae tribes, also called ‘the Core Lauraceae’, have arisen particular attention. In this review, we comprehensively collated the literatures on the phylogeny of Lauraceae published in recent years and summarized progress made in molecular systematic researches employing gene fragments, chloroplast genomes and DNA barcodings analyses. We clarified the phylogenetic relationships and main controversies of ‘the Core Lauraceae’, the systemic position of fuzzy genera (Neocinnamomum, Caryodaphnopsis and Cassytha) and the development of chloroplast genome and DNA barcodes. We further suggested and proposed the whole genome analysis and different inflorescence types would be possible to provide more information for further research on phylogenetic relationships and taxonomy of Lauraceae. Full article

Teas and various herbal teas are well-known beverages and are commonly consumed around the world. In this study, we focused on kuromoji tea. Kuromoji is a deciduous shrub of the Lauraceae family, and the plucked leaves and branches have been drunk as a tea in production areas for a long time. However, no studies have investigated the subjective and physiological effects of kuromoji tea. In this study, the effects of kuromoji tea were examined on the basis of the measurements of heart rate variability and cerebral blood flow, core body temperature and subjective assessments. Moreover, the results of this study showed that a pleasant subjective feeling could be obtained by sniffing the aroma of kuromoji teas, especially tea leaves. It was also found that the aroma of kuromoji teas has the potential to stimulate saliva secretion and increase subjective and physiological excitements in the oral cavity. 1,8-Cineole, linalool, terpinen-4-ol, carvone and geraniol were determined in both kuromoji leaves and branches. In this study, the beneficial effects of kuromoji teas when drunk conventionally were investigated. Full article