Intraspecific karyotypic polymorphism is highly concordant with allozyme variation in Lysimachia mauritiana (Primulaceae: Myrsinoideae) in Taiwan: implications for the colonization history and dispersal patterns of coastal plants

Intraspecific divergence in a coastal plant, Euphorbia jolkinii, at a major biogeographic boundary in East Asia

PREMISE

Quaternary climatic fluctuations and long-distance seed dispersal across the sea are critical factors affecting the distribution of coastal plants, but the spatiotemporal nature of population expansion and distribution change of East Asian coastal plants during this period are rarely examined. To explore this process, we investigated the genome-wide phylogenetic patterns of Euphorbia jolkinii Boiss. (Euphorbiaceae), which grows widely on littoral areas of Japan, Korea, and Taiwan.

METHODS

We used plastome sequences and genome-wide single nucleotide polymorphisms in samples across the species range to reveal phylogeographic patterns and spatiotemporal distributional changes. We conducted ecological niche modeling for the present and the last glacial maximum (LGM).

RESULTS

Genetic differentiation was observed between the northern and southern populations of E. jolkinii, separated by the major biogeographic boundary, the Tokara Gap. These two groups of populations differentiated during the glacial period and subsequently intermingled in the intermorainic areas of the central Ryukyu Islands after the LGM. Ecological niche models suggested that the potential range of E. jolkinii was restricted to southern Kyushu; however, it was widespread in the southern Ryukyu Islands and Taiwan during the LGM.

CONCLUSIONS

This study provides evidence of genetic differentiation among coastal plant populations separated by the prominent biogeographical boundary. Although coastal plants are typically expected to maintain population connectivity through sea-drifted seed dispersal, our findings suggest that genetic differences may arise because of a combination of limited gene flow and changes in climate during the glacial period.

In memoriam Ching-I Peng (1950-2018)-an outstanding scientist and mentor with a remarkable legacy

Ching-I Peng, the most prolific and internationally recognized Taiwanese plant taxonomist of his generation, passed away on May 1, 2018. Dr. Peng was an eminent worker on the taxonomy of East Asian plants and the genus Ludwigia, and the foremost expert on Asian Begonia. He served as associate editor, co-editor in chief, and editor-in-chief of Botanical Studies and its predecessor Botanical Bulletin of Academia Sinica during the period 1992-2016. He gathered over 25,000 plant specimens, name 121 plant taxa, and has left a remarkable legacy of literature, collaborations and collections. This article summarizes Dr. Peng's academic career and commemorates his enduring contribution.

Inhibition of varicella‑zoster virus replication by an ethanol extract of Lysimachia mauritiana

Varicella‑zoster virus (VZV), a ubiquitous human α‑herpesvirus, is the causative agent of chickenpox and shingles. In the present study, we investigated the antiviral activity of a 70% ethanol extract of Lysimachia mauritiana (LME) against VZV. LME strongly interfered with the replication of both laboratory and clinical strains of VZV without affecting the viability of MRC‑5 cells. Moreover, LME treatment suppressed the expression of an essential viral transactivator, immediate‑early 62 protein (IE62), in addition to other lytic genes in the later phases of viral replication. The finding that LME exerts potent inhibitory effects on VZV gene expression and replication supports its potential utility as a therapeutic anti‑viral agent.

Molecular Cytogenetic Analysis of Cucumis Wild Species Distributed in Southern Africa: Physical Mapping of 5S and 45S rDNA with DAPI

Wild Cucumis species have been divided into Australian/Asian and African groups using morphological and phylogenetic characteristics, and new species have been described recently. No molecular cytogenetic information is available for most of these species. The crossability between 5 southern African Cucumis species (C. africanus, C. anguria, C. myriocarpus, C. zeyheri, and C. heptadactylus) has been reported; however, the evolutionary relationship among them is still unclear. Here, a molecular cytogenetic analysis using FISH with 5S and 45 S ribosomal DNA (rDNA) was used to investigate these Cucumis species based on sets of rDNA-bearing chromosomes (rch) types I, II and III. The molecular cytogenetic and phylogenetic results suggested that at least 2 steps of chromosomal rearrangements may have occurred during the evolution of tetraploid C. heptadactylus. In step 1, an additional 45 S rDNA site was observed in the chromosome (type III). In particular, C. myriocarpus had a variety of rch sets. Our results suggest that chromosomal rearrangements may have occurred in the 45 S rDNA sites. We propose that polyploid evolution occurred in step 2. This study provides insights into the chromosomal characteristics of African Cucumis species and contributes to the understanding of chromosomal evolution in this genus.