BACKGROUND: Eriocaulon is a wetland plant genus with important ecological value, and one of the famous taxonomically challenging groups among angiosperms, mainly due to the high intraspecific diversity and low interspecific variation in the morphological characters of species within this genus. In this study, 22 samples representing 15 Eriocaulon species from China, were sequenced and combined with published samples of Eriocaulon to test the phylogenetic resolution using the complete chloroplast genome. Furthermore, comparative analyses of the chloroplast genomes were performed to investigate the chloroplast genome evolution of Eriocaulon. RESULTS: The 22 Eriocaulon chloroplast genomes and the nine published samples were proved highly similar in genome size, gene content, and order. The Eriocaulon chloroplast genomes exhibited typical quadripartite structures with lengths from 150,222 bp to 151,584 bp. Comparative analyses revealed that four mutation hotspot regions (psbK-trnS, trnE-trnT, ndhF-rpl32, and ycf1) could serve as effective molecular markers for further phylogenetic analyses and species identification of Eriocaulon species. Phylogenetic results supported Eriocaulon as a monophyletic group. The identified relationships supported the taxonomic treatment of section Heterochiton and Leucantherae, and the section Heterochiton was the first divergent group. Phylogenetic tree supported Eriocaulon was divided into five clades. The divergence times indicated that all the sections diverged in the later Miocene and most of the extant Eriocaulon species diverged in the Quaternary. The phylogeny and divergence times supported rapid radiation occurred in the evolution history of Eriocaulon. CONCLUSION: Our study mostly supported the taxonomic treatment at the section level for Eriocaulon species in China and demonstrated the power of phylogenetic resolution using whole chloroplast genome sequences. Comparative analyses of the Eriocaulon chloroplast genome developed molecular markers that can help us better identify and understand the evolutionary history of Eriocaulon species in the future.
Eriocaulaceae , Genome, Chloroplast , Phylogeny , Eriocaulaceae/genetics , Genome, Chloroplast/genetics , Mutation , Base Sequence
The essential oils from roots, branches, leaves and bark of Magnolia sumatrana var. glauca (Blume) Figlar & Noot and Magnolia hypolampra (Dandy) Figlar were extracted by ultrasonic-assisted extraction and the chemicals were determined by gas chromatography-mass spectroscopy (GC-MS). The major constitutes of M. sumatrana var. glauca were trans-cinnamaldehyde (27.55%), caryophyllene (1.20-10.14%), (+)-bulnesol (9.70%), α-caryophyllene (2.35-6.35%), α-eudesmol (1.08-6.17%). M. hypolampra was characterized by the presence of safrole (0.18-35.01%), (+) cycloisosativene (18.70%), oxirane, hexadecyl- (0.72-12.79%), ß-cubebene (1.53-8.90%), (Z)-14-tricosenyl formate (8.65%). This is the first study of the composition of essential oils from the roots, branches and bark of M. sumatrana var. glauca and the roots of M. hypolampra, and some compounds were being described for the first time. Combined with present results and literatures, phytochemicals may be affected by multi-factors such as organs, growing location, and extraction methods, providing more approaches for further exploration of the non-wood resources of forestry species.
Magnolia , Magnoliaceae , Oils, Volatile , Magnolia/chemistry , Trees , Oils, Volatile/chemistry , Plant Leaves/chemistry
Selaginella uncinata shows particularly rare blue leaves. Previous research has shown that structural interference by the cell wall of adaxial epidermal cells imparts blue coloration in leaves of S. uncinata; the objective of this study was to see whether anthocyanins might additionally contribute to this color, as changes in pH, and conjugation with metals and other flavonoids is also known to result in blue coloration in plants. We compared anatomical and biochemical traits of shade-grown (blue) S. uncinata leaves to high light (red) leaves of the same species and also to a non-blue (green) leaves of a congeneric S. kraussiana. By examining the anatomical structure, we found that the shape of adaxial epidermis of S. uncinata leaves was convex or lens-shaped on the lateral view and irregular circles with smooth embossment on the top view. These features were different from those of the abaxial and adaxial epidermis of S. kraussiana. We suspect that these structures increase the proportion of incident light entering the cell, deepening the leaf color, and therefore may be related to blue leaf color in S. uncinata. By examining biochemical traits, we found little difference in leaf pH value among the leaf types; all leaves contained several metal ions such as Mg, Fe, Mn, and copigments such as flavones. However, because there was no anthocyanin in blue S. uncinata leaves, we concluded that blue coloration in S. uncinata leaves is not caused by the three hypotheses of blue coloration: alkalization of the vacuole pH, metal chelation, or copigmentation with anthocyanins, but it may be related to the shape of the leaf adaxial epidermis.
Anthocyanins , Selaginellaceae , Anthocyanins/metabolism , Color , Humans , Plant Leaves/metabolism , Selaginellaceae/metabolism
The complete chloroplast (cp) genome sequence of Eriocaulon nepalense was sequenced and assembled in this study. The cp genome of E. nepalense is 150947 bp in length, composed of a pair of 26451 bp inverted repeat regions (IRs), separated by a large single-copy region (LSC) of 81064 bp, and a small single-copy region (SSC) of 16981 bp. The cp genome contained 114 unique genes, including 80 protein-coding genes, 30 tRNA genes, and 4 ribosomal RNA genes. The phylogenetic position of E. nepalense based on the cp genome data is closer to E. decemflorum than E. buergerianum.
