Transcriptome Sequencing Analysis Reveals a Difference in Monoterpene Biosynthesis between Scented Lilium ‘Siberia’ and Unscented Lilium ‘Novano’

Lilium is a world famous fragrant bulb flower with high ornamental and economic values, and significant differences in fragrance are found among different Lilium genotypes. In order to explore the mechanism underlying the different fragrances, the floral scents of Lilium ‘Sibeia’, with a strong fragrance, and Lilium ‘Novano’, with a very faint fragrance, were collected in vivo using a dynamic headspace technique. These scents were identified using automated thermal desorption—gas chromatography/mass spectrometry (ATD-GC/MS) at different flowering stages. We used RNA-Seq technique to determine the petal transcriptome at the full-bloom stage and analyzed differentially expressed genes (DEGs) to investigate the molecular mechanism of floral scent biosynthesis. The results showed that a significantly higher amount of Lilium ‘Siberia’ floral scent was released compared with Lilium ‘Novano’. Moreover, monoterpenes played a dominant role in the floral scent of Lilium ‘Siberia’; therefore, it is believed that the different emissions of monoterpenes mainly contributed to the difference in the floral scent between the two Lilium genotypes. Transcriptome sequencing analysis indicated that ~29.24 Gb of raw data were generated and assembled into 124,233 unigenes, of which 35,749 unigenes were annotated. Through a comparison of gene expression between these two Lilium genotypes, 6,496 DEGs were identified. The genes in the terpenoid backbone biosynthesis pathway showed significantly different expression levels. The gene expressions of 1-deoxy-D-xylulose 5-phosphate synthase (DXS), 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR), 4-hydroxy-3-methylbut-2-enyl diphosphate synthase (HDS), 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (HDR), isopentenyl diphosphate isomerase (IDI), and geranyl diphosphate synthase (GPS/GGPS), were upregulated in Lilium ‘Siberia’ compared to Lilium ‘Novano’, and two monoterpene synthase genes, ocimene synthase gene (OCS) and myrcene synthase gene (MYS), were also expressed at higher levels in the tepals of Lilium ‘Siberia’, which was consistent with the monoterpene release amounts. We demonstrated that the high activation levels of the pathways contributed to monoterpene biosynthesis in Lilium ‘Siberia’ resulting in high accumulations and emissions of monoterpenes, which led to the difference in fragrance between these two Lilium genotypes

Genome-wide identification, evolutionary, and expression analyses of histone H3 variants in plants

10.1155/2015/341598BioMed Research International201

Cloning of SoDXR and its role in monoterpenoids synthesis in Syringa oblata

Abstract [Objective] The purpose of this study is to examine the role of the DXR gene, encoding 1-deoxy- D-xylulose-5-phosphate reductoisomerase, in monoterpenoids synthesis in lilac (Syringa oblata), and to provide genetic resources and theoretical basis for the molecular breeding of floral fragrance of lilac. [Methods] Firstly, the SoDXR gene was cloned. Then, bioinformatics and subcellular localization analysis were performed, and qRT-PCR was used to analyze the gene expression patterns in different floral development stages and tissues. Finally, transient overexpression of SoDXR in the petals of snapdragon (Antirrhinum majus) was detected. [Results] ORF of SoDXR was 1 425 bp, encoding 474 amino acids. SoDXR protein contained the conserved domain of DXP_reductoisom, which had a similarity of up to 95% with Osmanthus fragrans and Olea europaea. Subcellular localization analysis showed that the protein was mainly located in the plastids, consistent with the software prediction. With flowering, the expression level of SoDXR was increased and then decreased, with the highest expression in the initial opening stage. SoDXR was differentially expressed in various tissues with the highest in petals and the lowest in stems. Transient overexpression revealed that the expression of SoDXR was higher than the control. Moreover, the main floral volatile components in snapdragon petals, myrcene and ocimene, were increased by 15.03 and 4.83 times, respectively. [Conclusion] The SoDXR gene positively regulates monoterpenoids synthesis in lilac, and may play an important role in the synthesis of secondary metabolites of floral fragrance

Antioxidant effect of aromatic volatiles emitted by <i>Lavandula dentata</i>, <i>Mentha spicata</i>, and <i>M. piperita</i> on mouse subjected to low oxygen condition

<p>This study aims to investigate the antioxidant effect of aromatic volatiles of three common aromatic plants, <i>Lavandula dentata</i>, <i>Mentha spicata</i>, and <i>M. piperita</i>. In this study, kunming mice subjected to low oxygen condition were treated with the volatiles emitted from these aromatic plants through inhalation administration. Then the blood cell counts, and the activities and gene expressions of antioxidant enzymes in different tissues were tested. The results showed that low oxygen increased the counts of red blood cells, white blood cells, and blood platelets of mice, and aromatic volatiles decreased their counts. Exposure to aromatic volatiles resulted in decreases in the malonaldehyde contents, and increases in the activities and gene expressions of superoxide dismutase, glutathione peroxidase, and catalase in different tissues under low oxygen. In addition, as the main component of aromatic volatiles, eucalyptol was the potential source that imparted positive antioxidant effect.</p> <p>Treatment with the volatiles emitted from aromatic plants through inhalation administration improving the antioxidative capability in mouse.</p

Genome-wide identification and expression analysis of the ZIP gene family in Quercus dentata

The ZIP (Zn-regulated, iron-regulated transporter-like protein) gene family is a novel metal transporter that is capable of absorbing and transporting a variety of metal cations, including zinc (Zn), iron (Fe), manganese (Mn), and cadmium (Cd). Quercus dentata Thunb. is a candidate plant species for the phytoremediation of heavy metal contaminated soil. A chromosome-scale genome assembly is reported recently for Q. dentata, however, genome-wide analysis of ZIP genes has not been performed. In this study, we identified 29 ZIP genes in Q. dentata genome using bioinformatics tools. The sequence homology, chromosomal distribution and phylogenetic relationship of these genes with ZIP genes from other plants indicated potential gene duplication during Q. dentata genome evolution. Sequence analysis revealed 23 conserved motifs in QdZIP proteins and 11 types of high-frequency cis-acting elements in the promoters of QdZIP genes. QdZIP proteins were predicted to localize on cell membrane except QdZIP7. QdZIP7 was predicted to be a chloroplast protein, which was confirmed using microscopic observation of QdZIP7-GFP fusion protein. QdZIP gene expression patterns in roots and exophytic mycorrhiza, leaves, stems and fruits were obtained from transcriptome data, and the responsiveness of QdZIP7 to excessive heavy metal Zn was detected using qRT-PCR. In summary, our study provided a basic sights on the ZIP gene family in Q. dentata, laying the foundation for in-depth investigation on the roles of the ZIP proteins in heavy metal transport

Statistics of annotation results for <i>Syringa oblata</i> unigenes.

<p>Statistics of annotation results for <i>Syringa oblata</i> unigenes.</p

Distribution of genes among each flower developmental stage.

<p>a: Venn diagram illustrating the expression patterns of genes among flower developmental stages. b: Number of DEGs in each flower developmental stage. DEGs are compared between developmental stages. SOFB, flower bud stage; SOB, bud stage; SOF, flowering stage.</p