Camphor tree [Cinnamomum camphora (L.) J. Presl], a species in the magnoliid family Lauraceae, is known for its rich volatile oils and is used as a medical cardiotonic and as a scent in many perfumed hygiene products. Here, we present a high-quality chromosome-scale genome of C. camphora with a scaffold N50 of 64.34 Mb and an assembled genome size of 755.41 Mb. Phylogenetic inference revealed that the magnoliids are a sister group to the clade of eudicots and monocots. Comparative genomic analyses identified two rounds of ancient whole-genome duplication (WGD). Tandem duplicated genes exhibited a higher evolutionary rate, a more recent evolutionary history and a more clustered distribution on chromosomes, contributing to the production of secondary metabolites, especially monoterpenes and sesquiterpenes, which are the principal essential oil components. Three-dimensional analyses of the volatile metabolites, gene expression and climate data of samples with the same genotype grown in different locations showed that low temperature and low precipitation during the cold season modulate the expression of genes in the terpenoid biosynthesis pathways, especially TPS genes, which facilitates the accumulation of volatile compounds. Our study lays a theoretical foundation for policy-making regarding the agroforestry applications of camphor tree.

Cinnamomum camphora is an evergreen tree that contains essential oils and the leaf is the main organ used to extract essential oils. Isoprenoid is a key component contributing to the essential oils of C. camphora. Still, the molecular mechanisms and regulatory pathways underlying isoprenoid biosynthesis remain to be explored. In our study, we found that the content of linalool was higher in 65-day-old leaves than that in 15-day-old leaves of linalool-type C. camphora. The leaf proteome of these two materials was then analyzed based on data-independent acquisition, respectively, and 11,503 proteins were identified, of which 11,076 were annotated. Analysis of differentially expressed proteins revealed that the expression levels of MCT, MDS, and AACT increased significantly in 65-day-old leaves. Further analysis of the protein interaction network indicated that 15 differentially expressed proteins related to isoprenoid biosynthesis were co-expressed, and also suggested that the transcription factor families of BES1, C3H, MYB, NF-YC, Nin-like, WRKY, ZF-HD, and bHLH may act as candidate regulators of leaf development in C. camphora. Our study verified that the process of isoprenoid biosynthesis in C. camphora is regulated by a complicated network consisting of conserved synthetases, and provides proteomic information for further investigation of isoprenoid metabolic.

Bhesa xieii, a new species of Centroplacaceae from southern China, is described and illustrated. Morphological comparison with Bhesa robusta, B. paniculata and B. ceylanica is provided. Both morphological and molecular evidences clearly indicate that B. xieii is a distinct species. It differs in capsules narrowly ovate, ca. 3 cm long, apex obtuse, peduncle thick, ca. 3 mm long; racemes; flowers pale yellow, pedicels 1.5–2.5 mm long; calyx lobes broadly ovate to subrotundate, apex obtuse; petals ovate to oblong-elliptic, apex obtuse, inflexed; lamina oblong-elliptic to narrowly ovate, base obtuse or subtruncate, apex acute or obtuse.

Camphor tree (Cinnamomum camphora (L.) J. Presl), a species in the magnoliid family Lauraceae, is known for its rich volatile oils and is used as a medical cardiotonic and as a scent in many perfumed hygiene products. Here, we present a high-quality chromosome-scale genome of C. camphora with a scaffold N50 of 64.34 Mb and an assembled genome size of 755.41 Mb. Phylogenetic inference revealed that the magnoliids are a sister group to the clade of eudicots and monocots. Comparative genomic analyses identified two rounds of ancient whole-genome duplication (WGD). Tandem duplicated genes exhibited a higher evolutionary rate, a more recent evolutionary history and a more clustered distribution on chromosomes, contributing to the production of secondary metabolites, especially monoterpenes and sesquiterpenes, which are the principal essential oil components. Three-dimensional analyses of the volatile metabolites, gene expression and climate data of samples with the same genotype grown in different locations showed that low temperature and low precipitation during the cold season modulate the expression of genes in the terpenoid biosynthesis pathways, especially TPS genes, which facilitates the accumulation of volatile compounds. Our study lays a theoretical foundation for policy-making regarding the agroforestry applications of camphor tree.