Comparative Analysis of Luisia (Aeridinae, Orchidaceae) Plastomes Shed Light on Plastomes Evolution and Barcodes Investigation.

Luisia, a genus of the subtribe Aeridinae of Orchidaceae, comprises ca. 40 species. Members of Luisia exhibit unique morphological characteristics and represent a valuable ornamental orchid genus. However, due to the scarcity of distinct morphological characters, species identification within this genus is ambiguous and controversial. In the present study, next-generation sequencing (NGS) methods were used to assemble the plastomes of five Luisia species and compare them with one publicly available Luisia plastid genome data. The plastomes of Luisia possessed a quadripartite structure, with sizes ranging from 146,243 bp to 147,430 bp. The plastomes of six Luisia species contained a total of 120 genes, comprising 74 protein-coding genes, 38 tRNA genes and eight rRNA genes. Notably, all ndh genes were pseudogenized or lost. An analysis of codon usage bias showed that leucine (Leu) exhibited the highest frequency, while cysteine (Cys) exhibited the lowest frequency. A total of 57 to 64 SSRs and 42 to 49 long repeats were identified. Five regions and five coding sequences were identified for DNA barcodes, based on the nucleotide diversity (Pi) analysis. The species of Luisia constituted a monophyletic group and were sister to Paraphalaenopsis with strong support. Our study deepens the understanding of species identification, plastome evolution and the phylogenetic positions of Luisia.

Genome-wide analysis of the TCP gene family and their expression pattern in Cymbidium goeringii.

TCP gene family are specific transcription factors for plant, and considered to play an important role in development and growth. However, few related studies investigated the TCP gene trait and how it plays a role in growth and development of Orchidaceae. In this study, we obtained 14 TCP genes (CgTCPs) from the Spring Orchid Cymbidium goeringii genome. The classification results showed that 14 CgTCPs were mainly divided into two clades as follows: four PCF genes (Class I), nine CIN genes and one CYC gene (Class II). The sequence analysis showed that the TCP proteins of C. goeringii contain four conserved regions (basic Helix-Loop-Helix) in the TCP domain. The exon-intron structure varied in the clade according to a comparative investigation of the gene structure, and some genes had no introns. There are fewer CgTCP homologous gene pairs compared with Dendrobium catenatum and Phalaenopsis equestris, suggesting that the TCP genes in C. goeringii suffered more loss events. The majority of the cis-elements revealed to be enriched in the function of light responsiveness, followed by MeJA and ABA responsiveness, demonstrating their functions in regulating by light and phytohormones. The collinearity study revealed that the TCPs in D. catenatum, P. equestris and C. goeringii almost 1:1. The transcriptomic data and real-time reverse transcription-quantitative PCR (RT-qPCR) expression profiles showed that the flower-specific expression of the TCP class II genes (CgCIN2, CgCIN5 and CgCIN6) may be related to the regulation of florescence. Altogether, this study provides a comprehensive analysis uncovering the underlying function of TCP genes in Orchidaceae.

The Melastoma dodecandrum genome and the evolution of Myrtales.

Melastomataceae has abundant morphological diversity with high economic and ornamental merit in Myrtales. The phylogenetic position of Myrtales is still contested. Here, we report the chromosome-level genome assembly of Melastoma dodecandrum in Melastomataceae. The assembled genome size is 299.81 Mb with a contig N50 value of 3.00 Mb. Genome evolution analysis indicated that M. dodecandrum, Eucalyptus grandis, and Punica granatum were clustered into a clade of Myrtales and formed a sister group with the ancestor of fabids and malvids. We found that M. dodecandrum experienced four whole-genome polyploidization events: the ancient event was shared with most eudicots, one event was shared with Myrtales, and the other two events were unique to M. dodecandrum. Moreover, we identified MADS-box genes and found that the AP1-like genes expanded, and AP3-like genes might have undergone subfunctionalization. The SUAR63-like genes and AG-like genes showed different expression patterns in stamens, which may be associated with heteranthery. In addition, we found that LAZY1-like genes were involved in the negative regulation of stem branching development, which may be related to its creeping features. Our study sheds new light on the evolution of Melastomataceae and Myrtales, which provides a comprehensive genetic resource for future research.

Effects of leptin-modified human placenta-derived mesenchymal stem cells on angiogenic potential and peripheral inflammation of human umbilical vein endothelial cells (HUVECs) after X-ray radiation.

Combined radiation-wound injury (CRWI) is characterized by blood vessel damage and pro-inflammatory cytokine deficiency. Studies have identified that the direct application of leptin plays a significant role in angiogenesis and inflammation. We established a sustained and stable leptin expression system to study the mechanism. A lentivirus method was employed to explore the angiogenic potential and peripheral inflammation of irradiated human umbilical vein endothelial cells (HUVECs). Leptin was transfected into human placenta-derived mesenchymal stem cells (HPMSCs) with lentiviral vectors. HUVECs were irradiated by X-ray at a single dose of 20 Gy. Transwell migration assay was performed to assess the migration of irradiated HUVECs. Based on the Transwell systems, co-culture systems of HPMSCs and irradiated HUVECs were established. Cell proliferation was measured by cell counting kit-8 (CCK-8) assay. The secretion of pro-inflammatory cytokines (human granulocyte macrophage-colony stimulating factor (GM-CSF), interleukin (IL)-1α, IL-6, and IL-8) was detected by enzyme-linked immunosorbent assay (ELISA). The expression of pro-angiogenic factors (vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF)) mRNA was detected by real-time quantitative polymerase chain reaction (RT-qPCR) assay. Relevant molecules of the nuclear factor-κB (NF-κB) and Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathways were detected by western blot assay. Results showed that leptin-modified HPMSCs (HPMSCs/ leptin) exhibited better cell proliferation, migration, and angiogenic potential (expressed more VEGF and bFGF). In both the single HPMSCs/leptin and the co-culture systems of HPMSCs/leptin and irradiated HUVECs, the increased secretion of pro-inflammatory cytokines (human GM-CSF, IL-1α, and IL-6) was associated with the interaction of the NF-κB and JAK/STAT signaling pathways. We conclude that HPMSCs/leptin could promote angiogenic potential and peripheral inflammation of HUVECs after X-ray radiation.