As a class of small non-coding RNAs, microRNA (miRNA) is widely present and plays important regulatory roles in plant growth, development and stress response. Based on the mechanism of miRNAs in plants, we review the identification of miRNAs in some genera of Orchidaceae, the specific functions of several miRNAs and other relevant studies on miRNAs in the last decade, in order to provide a reference for better understanding function and regulatory network of small RNAs in orchids.
MicroRNAs/genetics* ; Orchidaceae/genetics* ; Plants/genetics*

Bletilla striata has been used as traditional Chinese medicine for several centuries. In recent years, the quality and quantity of wild B. striata plants have declined sharply due to habitat deterioration and human over-exploitation. Therefore, it is of great urgency to evaluate and protect B. striata wild plant resource. In this study, sequence-related amplified polymorphism (SRAP) markers were applied to assess the level and pattern of genetic diversity in twelve populations of B. striata. The results showed a high level of genetic diversity (PPB = 90.48%, H = 0.349 4, I = 0.509 6) and moderate genetic differentiation among populations (G(st) = 0.260 9). Based on the unweighted pair-group method with arithmetic average (UPGMA), twelve populations gathered in three clusters. The cluster 1 included four populations. There are Nanjing, Zhenjiang, Xuancheng and Hangzhou. The seven populations which come from Hubei Province, Hunan Province, Jiangxi Province and Guizhou Province belonged to the cluster 2. The cluster 3 only contained Wenshan population. Moreover, Mantel test revealed significant positive correlation between genetic distances and geographic distances (r = 0.632 9; P < 0.000 1). According to the results, we proposed a series of conservation consideration for B. striata.
China ; Genetic Markers ; Genetic Variation ; Genetics, Population ; Orchidaceae ; genetics ; Phylogeny ; Plants, Medicinal ; genetics

Genetic transformation is an effective method to improve breeding objective traits of orchids. However, there is little information about genetic transformation of Cymbidium sinensis. Rhizomes from shoot-tip culture of C. sinensis cv. 'Qijianbaimo' were used to establish a practical transformation protocol of C. sinensis. Pre-culture time, concentration and treating methods of acetosyringone, concentration of infection bacteria fluid (OD600), infection time, and co-culture time had significant effects on β-glucuronidase (GUS) transient expression rate of C. sinensis cv. 'Qijianbaimo' rhizome. The GUS transient expression rate of rhizome was the highest (11.67%) when rhizomes pre-cultured for 39 d were soaked in bacterium suspension (OD600 = 0.9) supplemented with 200 μmol/L acetosyringone for 35 min, followed by culturing on co-culture medium supplemented with 200 μmol/L acetosyringone for 7 d. Under this transformation conditions, 3 transgenic plantlets, confirmed by GUS histochemical assay and PCR, were obtained from 400 regenerated plantlets, and the genetic transformation rate was 0.75%. This proved that it was feasible to create new cultivars by the use of Agrobacterium-mediated genetic transformation in C. sinense.
Agrobacterium ; Coculture Techniques ; Genetic Engineering ; Glucuronidase ; Orchidaceae ; genetics ; Plants, Genetically Modified ; genetics ; Polymerase Chain Reaction ; Transformation, Genetic

To identify adulterants from medicinal plants of Bletilla H. G. Reichenbach, the suitable candidate DNA barcoding of Bletilla was evaluated. In this study, the internal transcribed spacer (ITS) of nuclear ribosomal DNA, the LFY homologous gene intron 2 and chloroplast ycfl gene were amplified and sequenced from forty-one samples. The intra-specific and inter-specific divergences of Bletilla were calculated, and the identification efficiency was assessed using Barcoding Gap, NJ tree by K2P distance and BLAST1 method. The result showed the intra-specific divergence of nrDNA ITS and ycJfl (0.022-0.106 and 0.017-0.106) were obviously higher than the inter-specific divergence (0-0.012 and 0-0.015), and four species of Bletilla were also accurately distinguished in NJ trees. Whereas, there was no Barcoding Gap on LFY homologous gene intron 2, thus it cannot effectively identify species of Bletilla. Using NJ tree of nrDNA ITS and ycfl gene, powdery medicine and the adulterants of Bletilla were successfully unidentified. In conclusion, nrDNA ITS and ycfl can be used as a potential DNA barcoding to identify the medicinal plants in Bletilla and its adulterants. There were only three basic differences on nrDNA ITS between "Jujing baiji" and Bletilla striata of Lu'an in Anhui province, and two basic differences in ycfl. Based on morphological and molecular data, "Jujing baiji" could be recognized as the species of Bletilla striata.
Base Sequence ; DNA Barcoding, Taxonomic ; DNA, Plant ; genetics ; DNA, Ribosomal Spacer ; genetics ; Orchidaceae ; classification ; Plants, Medicinal ; classification

To establish a molecular identification method for Bletillae Rhizoma, this paper extracted genome DNA from Bletillae Rhizoma and its adulterants. The sequences of rDNA ITS2 were sequenced after amplifying. Then multiple alignments of ITS2 were constructed phylogenetic tree with Neighbor Joining by MEGA 5. 1 and found out SNPs loci. The result showed that rDNA ITS2 region could identify Bletillae Rhizoma and its adulterants. There existed the SNPs loci, which could identify Bletilla striata and B. ochracea. Furthermore, we designed specific primers against the SNPs loci of B. striata and B. ochracea, then screened primers and optimized the PCR amplification conditions. Finally, the DNA of B. striata and B. ochracea were specifically amplified by BJ59-412F, BJ59-412R and HHBJ-225R. The length of amplification products were respectively about 350 bp and 520 bp that were effectively identified of B. striata and B. ochracea. While, the adulterants of Bletillae Rhizoma were no-reaction occurring. To sum up, the amplification conditions of the primers can identify B. striata, B. ochracea and their adulterants successfully at the same time. This method was easy, time-saving, and reliable, which can be used as a rapid method for molecular identification of Bletillae Rhizoma.
Base Sequence ; DNA Primers ; genetics ; DNA, Intergenic ; genetics ; DNA, Plant ; genetics ; Drug Contamination ; prevention & control ; Molecular Sequence Data ; Orchidaceae ; classification ; genetics ; Phylogeny ; Polymorphism, Single Nucleotide ; Rhizome ; classification ; genetics

The LEAFY (LFY) homologous gene of Dendrobium moniliforme (L.) Sw. was cloned by new primers which were designed based on the conservative region of known sequences of orchid LEAFY gene. Partial LFY homologous gene was cloned by common PCR, then we got the complete LFY homologous gene Den LFY by Tail-PCR. The complete sequence of DenLFY gene was 3 575 bp which contained three exons and two introns. Using BLAST method, comparison analysis among the exon of LFY homologous gene indicted that the DenLFY gene had high identity with orchids LFY homologous, including the related fragment of PhalLFY (84%) in Phalaenopsis hybrid cultivar, LFY homologous gene in Oncidium (90%) and in other orchid (over 80%). Using MP analysis, Dendrobium is found to be the sister to Oncidium and Phalaenopsis. Homologous analysis demonstrated that the C-terminal amino acids were highly conserved. When the exons and introns were separately considered, exons and the sequence of amino acid were good markers for the function research of DenLFY gene. The second intron can be used in authentication research of Dendrobium based on the length polymorphism between Dendrobium moniliforme and Dendrobium officinale.
Amino Acid Sequence ; Base Sequence ; DNA, Plant ; genetics ; Dendrobium ; genetics ; Exons ; Introns ; Orchidaceae ; genetics ; Phylogeny ; Plant Leaves ; genetics ; Plant Proteins ; genetics ; Plants, Medicinal ; genetics ; Sequence Alignment ; Sequence Homology, Amino Acid

In order to identify genes involved in floral transition and development of the orchid species, a full-length APETALA1/FRUITFULL-like (AP1/FUL-like) MADS box cDNA was cloned from Cymbidium faberi (C. faberi) sepals and designated as C. faberi APETALA1-like (CfAP11], JQ031272.1). The deduced amino acid sequence of CfAP11 shared 84% homology with a member of the AP1/FUL-like group of MADS box genes (AY927238.1, Dendrobium thyrsiflorum FUL-like MADS box protein 3 mRNA). Phylogenetic analysis shows that CfAP11 belonged to the AP1/FUL transcription factor subfamily. Bioinformatics analysis shows that the deduced protein had a MADS domain and a relatively conservative K region. The secondary structure of CfAP11 mainly consisted of alpha helices (58.97%), and the three-dimensional structure of the protein was similar to that of homologues in Roza hybrida, Oryza sativa and Narcissus tazetta. Real-time quantitative PCR (qRT-PCR) results reveal low levels of its mRNA in roots, lower levels in leaves during reproductive period than vegetative period, and higher levels in pedicels at full-blossom stage than at bud stage. These results suggest that CfAP11 is involved in floral induction and floral development. Additionally, we observed higher levels of CfAP11 expression in pedicels and ovaries than in other tissues during full-blossom stage, which suggests that CfAP11 may also be involved in fruit formation in certain mechanism.
Amino Acid Sequence ; Cloning, Molecular ; Flowers ; genetics ; metabolism ; Gene Expression Regulation, Plant ; Genes, Plant ; MADS Domain Proteins ; genetics ; Molecular Sequence Data ; Orchidaceae ; genetics ; metabolism ; Plant Proteins ; genetics ; metabolism ; Spatio-Temporal Analysis