Abstract Background Physalis L. is a genus of herbaceous plants of the family Solanaceae, which has important medicinal, edible, and ornamental values. The morphological characteristics of Physalis species are similar, and it is difficult to rapidly and accurately distinguish them based only on morphological characteristics. At present, the species classification and phylogeny of Physalis are still controversial. In this study, the complete chloroplast (cp) genomes of four Physalis species ( Physalis angulata , P. alkekengi var. franchetii , P. minima and P. pubescens ) were sequenced, and the first comprehensive cp genome analysis of Physalis was performed, which included the previously published cp genome sequence of Physalis peruviana . Results The Physalis cp genomes exhibited typical quadripartite and circular structures, and were relatively conserved in their structure and gene synteny. However, the Physalis cp genomes showed obvious variations at four regional boundaries, especially those of the inverted repeat and the large single-copy regions. The cp genomes’ lengths ranged from 156,578 bp to 157,007 bp. A total of 114 different genes, 80 protein-coding genes, 30 tRNA genes, and 4 rRNA genes, were observed in four new sequenced Physalis cp genomes. Differences in repeat sequences and simple sequence repeats were detected among the Physalis cp genomes. Phylogenetic relationships among 36 species of 11 genera of Solanaceae based on their cp genomes placed Physalis in the middle and upper part of the phylogenetic tree, with a monophyletic evolution having a 100% bootstrap value. Conclusion Our results enrich the data on the cp genomes of the genus Physalis . The availability of these cp genomes will provide abundant information for further species identification, increase the taxonomic and phylogenetic resolution of Physalis , and assist in the investigation and utilization of Physalis plants.
The over-collection and habitat destruction of natural Dendrobium populations for their commercial medicinal value has led to these plants being under severe threat of extinction. In addition, many Dendrobium plants are similarly shaped and easily confused during the absence of flowering stages. In the present study, we examined the application of the ITS2 region in barcoding and phylogenetic analyses of Dendrobium species (Orchidaceae). For barcoding, ITS2 regions of 43 samples in Dendrobium were amplified. In combination with sequences from GenBank, the sequences were aligned using Clustal W and genetic distances were computed using MEGA V5.1. The success rate of PCR amplification and sequencing was 100%. There was a significant divergence between the inter- and intra-specific genetic distances of ITS2 regions, while the presence of a barcoding gap was obvious. Based on the BLAST1, nearest distance and TaxonGAP methods, our results showed that the ITS2 regions could successfully identify the species of most Dendrobium samples examined; Second, we used ITS2 as a DNA marker to infer phylogenetic relationships of 64 Dendrobium species. The results showed that cluster analysis using the ITS2 region mainly supported the relationship between the species of Dendrobium established by traditional morphological methods and many previous molecular analyses. To sum up, the ITS2 region can not only be used as an efficient barcode to identify Dendrobium species, but also has the potential to contribute to the phylogenetic analysis of the genus Dendrobium.
Dendrobium seedlings showed low survival rate when they were transferred from in vitro conditions to greenhouse or field environment. One of the major reasons is their low tolerance to environmental changes. WRKY transcription factors are one of the largest families of transcriptional regulators in plants. They are involved in various biotic and abiotic stress responses. One DnWRKY11 gene was isolated from Dendrobium nobile. To explore the function of DnWRKY11 in Dendrobium defense responses to abiotic stress, it was overexpressed in tobacco. Under salt and drought stresses, the DnWRKY11 transgenic tobacco showed higher germination rate, longer root length, higher fresh weight, higher activities of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and lower content of malonidialdehyde (MDA) than the wild type. These results proved the important roles of DnWRKY11 in plant response to drought and salt stresses, and provided a potential gene for improving environmental stress tolerance of Dendrobium seedlings.
IFI-200 protein family is a group of highly conserved interferon-inducible proteins,each of which contains one or several characteristic 200 amino acid domains at its C-terminal.At present,ten members have already been found in the IFI-200 protein family.Among them,six members are from mice,including p202a,p202b,p203,p204,p205 and p206.And four other members are from humans,which are IFI16,MNDA,AIM2 and IFIX.IFI-200 family members have been known to be involved in the regulation of cell growth,cell senescence,cell differentiation and cell death.But recently,more and more evidences showed IFI-200 family members play roles in human cancers and autoimmune diseases.
Objective Genetic diversity and affinity relationships among 13 species of Dendrobium Sw.were analyzed,the result laid a solid foundation for the better use of this resources.Methods Random amplified polymorphic DNA(RAPD) technique was used to analyze genetic diversity,and the dendrogram was constructed by UPGMA.Results Ten RAPD primers were applied to do random amplification.A total of 188 DNA bands was detected,180 among which were polymorphic,the average rate of polymorphic bands was 95.74%.The result of cluster analysis by using UPGMA method showed that 13 genotypes could be classified into three types in genetic distance 0.63.This outcome was corresponding to the result by using traditional classification.Conclusion It is concluded that RAPD markers can be used on the studies of genetic relationships and classification of species of Dendrobium Sw.sensitively.
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