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Background: Mikania micrantha H.B.K. (Asteraceae) is one of the world's most invasive weeds which has been rapidly expanding in tropical Asia, including China, while its close relative M. cordata, the only Mikania species native to China, shows no harm to the local ecosystems. These two species are very similar in morphology but differ remarkably in several ecological and physiological traits, representing an ideal system for comparative analysis to investigate the genetic basis underlying invasion success. In this study, we performed RNA-sequencing on the invader M. micrantha and its native congener M. cordata in China, to unravel the genetic basis underlying the strong invasiveness of M. micrantha. For a more robust comparison, another non-invasive congener M. cordifolia was also sequenced and compared. Results: A total of 52,179, 55,835, and 52,983 unigenes were obtained for M. micrantha, M. cordata, and M. cordifolia, respectively. Phylogenetic analyses and divergence time dating revealed a relatively recent split between M. micrantha and M. cordata, i.e., approximately 4.81 million years ago (MYA), after their divergence with M. cordifolia (8.70 MYA). Gene ontology classifications, pathway assignments and differential expression analysis revealed higher representation or significant up-regulation of genes associated with photosynthesis, energy metabolism, protein modification and stress response in M. micrantha than in M. cordata or M. cordifolia. Analysis of accelerated evolution and positive selection also suggested the importance of these related genes and processes to the adaptability and invasiveness of M. micrantha. Particularly, most (77 out of 112, i.e. 68.75%) positively selected genes found in M. micrantha could be classified into four groups, i.e., energy acquisition and utilization (10 genes), growth and reproduction (13 genes), protection and repair (34 genes), and signal transduction and expression regulation (20 genes), which may have contributed to the high adaptability of M. micrantha to various new environments and the capability to occupy a wider niche, reflected in its high invasiveness. Conclusions: We characterized the transcriptomes of the invasive species M. micrantha and its non-invasive congeners, M. cordata and M. cordifolia. A comparison of their transcriptomes provided insights into the genetic basis of the high invasiveness of M. micrantha. [ABSTRACT FROM AUTHOR]

Abstract: Aim: The genus Xylocarpus contains two mangrove species, X. granatum and X. moluccensis, and a rare non‐mangrove, X. rumphii. The two mangrove species are ideal models to study the biogeography of coastal plants with a unique dispersal ability, that is via buoyant propagules. We constructed the phylogeny of Xylocarpus and its relatives and determined the population structures of the two mangrove species. We aimed to elucidate the roles of continental drift and long‐distance dispersal (LDD) in shaping the present‐day distribution of Xylocarpus and to determine the factors affecting the patterns of population differentiation. Location: The Indo‐West Pacific (IWP) region. Methods: Thirty populations of X. granatum, 15 of X. moluccensis and four of X. rumphii were sampled across the IWP region. Five chloroplast DNA intergenic spacers were sequenced for Xylocarpus and outgroup species to determine divergence times. The genetic diversity, divergence and structure of the two mangrove species were further analysed using five nuclear and two chloroplast DNA loci. Migrations between oceanic regions were estimated. Results: The genus Xylocarpus diverged from its sister genus Carapa approximately 19.4 Ma. The populations of X. granatum differentiated into three groups, with genetic breaks present across the Malay Peninsula and Wallacea, whereas X. moluccensis populations differentiated into two groups, with a genetic break present only across the Malay Peninsula. Migration was also observed between populations of the Southeast Asian and Australasian regions in X. moluccensis but not in X. granatum. Main conclusion: Since Xylocarpus originated after the breakup of Gondwana and subsequent plate motions, its current distribution range should have been facilitated by present‐day LDD instead of past continental drift. Despite the capacity of LDD, the presence of differing population structures across land barriers (the Sunda and Sahul Shelves) and ocean currents indicated differential limitations in the dispersal capabilities of X. granatum and X. moluccensis. [ABSTRACT FROM AUTHOR]

Excoecaria agallocha is one of the predominant mangrove species in the Indo-West Pacific (IWP) region with an extensive range of distribution. To infer the current geographical patterns of genetic variation and provide new insights on the historical population dynamics of mangrove species in the IWP region, we sampled E. agallocha across its distribution range and investigated the phylogeography of this species using four chloroplast DNA (cpDNA) fragments. Our results showed that E. agallocha possessed a high degree of species-level genetic diversity, while the average genetic diversity within populations was much lower. The presence of population genetic structure was supported by the estimates of genetic differentiation and the analysis of molecular variance (AMOVA). Of the ten haplotypes identified, no haplotypes were shared between the East Indian Ocean (EIO), the West Pacific Ocean (WPO), and the North Australian (NA) regions. Genealogy analysis, haplotype distribution patterns, and the principal coordinate analysis (PCoA) consistently suggested the existence of three haplotype groups distributed in distinct geographical locations. The genealogical breaks observed and further analysis of geographic/genetic barriers indicated that both land barriers and oceanic currents may have played important roles in the divergence and demography of E. agallocha. [ABSTRACT FROM AUTHOR]

Premise of the Study: We isolated and characterized 16 expressed sequence tag–simple sequence repeat (EST‐SSR) markers in Itea chinensis (Iteaceae), a common evergreen broadleaf tree, for future studies on the genetic diversity and spatial genetic structure of the species. Methods and Results: Based on transcriptome data of I. chinensis, a total of 36 primer pairs were initially designed and tested. Of these, 16 were successfully amplified and showed clear polymorphism. For these markers, the number of alleles per locus varied from two to 15. The observed and expected heterozygosity ranged from 0 to 0.600 and 0.072 to 0.554, respectively. Furthermore, all loci were successfully cross‐amplified in two congeneric species, I. oblonga and I. yangchunensis. Conclusions: The EST‐SSR markers described here can be used to study the genetic diversity and phylogeographic patterns of I. chinensis and other related species in Itea. [ABSTRACT FROM AUTHOR]

Camellia ptilophylla is a natural caffeine-free tea plant endemic to China with high commercial and therapeutic values. Here, we report the complete chloroplast genome assembled using Illumina pair-end sequencing data. The chloroplast genome was 157,097 bp in length, with a large single copy (LSC) region of 86,631 bp, a small single copy (SSC) region of 18,286 bp, separated by two inverted repeat (IR) regions of 26,090 bp each. It contains a total of 132 genes, with an overall GC content of 37.3%. The phylogenetic analysis showed that C. ptilophylla is sister to a congeneric species, C. reticulata. [ABSTRACT FROM AUTHOR]