Project description:MicroRNAs (miRNAs) are essential small RNA molecules that regulate the expression of target mRNAs in plants and animals. Here, we aimed to identify miRNAs and their putative targets in Hibiscus syriacus, the national flower of South Korea. Therefore, we employed high-throughput sequencing of small RNAs obtained from four different tissues (i.e., leaf, root, flower, and ovary) and identified 33 conserved and 30 novel miRNA families, many of which showed differential tissue-specific expressions. In addition, we computationally predicted novel targets of miRNAs and validated some of them using 5′ rapid amplification of cDNA ends analysis. One of the validated novel targets of miR477 was a terpene synthase, the primary gene involved in the formation of disease-resistant terpene metabolites such as sterols and phytoalexins. In addition, a predicted target of conserved miRNAs, miR396, is SHORT VEGETATIVE PHASE, which is involved in flower initiation and is duplicated in Hibiscus syriacus. Collectively, this study provides the first reliable draft of the Hibiscus syriacus miRNA transcriptome that should constitute a basis for understanding the biological roles of miRNAs in Hibiscus syriacus.
2017-09-08 | GSE99329 | GEO
Project description:Terpene synthase gene amplicons from subseafloor sediments
Project description:Analysis of white adipose tissue of PPARb/d knockout mice. Data may point towards putative target genes of PPARb/d and thus the function of PPARb/d in white adipose tissue. Datasets were used to identify glycogen synthase 2 as novel PPAR target. Keywords: gene expression array-based, count
Project description:<p><strong>BACKGROUND:</strong> Plants exhibit wide chemical diversity due to the production of specialized metabolites that function as pollinator attractants, defensive compounds, and signaling molecules. Lamiaceae (mints) are known for their chemodiversity and have been cultivated for use as culinary herbs, as well as sources of insect repellents, health-promoting compounds, and fragrance.</p><p><strong>FINDINGS:</strong> We report the chromosome-scale genome assembly of Callicarpa americana L. (American beautyberry), a species within the early-diverging Callicarpoideae clade of Lamiaceae, known for its metallic purple fruits and use as an insect repellent due to its production of terpenoids. Using long-read sequencing and Hi-C scaffolding, we generated a 506.1-Mb assembly spanning 17 pseudomolecules with N50 contig and N50 scaffold sizes of 7.5 and 29.0 Mb, respectively. In all, 32,164 genes were annotated, including 53 candidate terpene synthases and 47 putative clusters of specialized metabolite biosynthetic pathways. Our analyses revealed 3 putative whole-genome duplication events, which, together with local tandem duplications, contributed to gene family expansion of terpene synthases. Kolavenyl diphosphate is a gateway to many of the bioactive terpenoids in C. americana; experimental validation confirmed that CamTPS2 encodes kolavenyl diphosphate synthase. Syntenic analyses with Tectona grandis L. f. (teak), a member of the Tectonoideae clade of Lamiaceae known for exceptionally strong wood resistant to insects, revealed 963 collinear blocks and 21,297 C. americana syntelogs.</p><p><strong>CONCLUSIONS:</strong> Access to the C. americana genome provides a road map for rapid discovery of genes encoding plant-derived agrichemicals and a key resource for understanding the evolution of chemical diversity in Lamiaceae.</p>
Project description:The corm of Hypoxis hemerocallidea, commonly known as the African potato, is used in traditional medicine to treat several medical conditions, such as urinary infections, benign prostate hyperplasia, inflammatory conditions and testicular tumours amongst others. The metabolites of H. hemerocallidea have been identified in several studies. More recently, the terpenoids of the plant have been identified. However, the biochemical pathways and the enzymes involved in the production of metabolites have not been characterised. In this study, total RNA extracted from the corm, leaf and flower tissues of H. hemerocallidea was sequenced on the Illumina HiSeq 2500 platform. A total of 143,549 transcripts were assembled de novo using Trinity and 107,131 transcripts were functionally annotated between the nr, GO, COG, KEGG and SWISS-PROT databases. Additionally, the proteome of the three tissues was sequenced using LC-MS/MS, revealing aspects of secondary metabolism and serving as data validation for the transcriptome. Functional annotation led to the identification of numerous terpene synthases such as nerolidol synthase, germacrene D synthase and cycloartenol synthase amongst others. Transcripts were also annotated to encode for the terpene phytoalexin momilactone A synthase. Differential expression analysis using edgeR identified 946 transcripts differentially expressed between the three tissues and revealed that the leaf upregulates linalool synthase compared to the corm and the flower tissues. The transcriptome as well as the proteome of Hypoxis hemerocallidea presented here provide a foundation for future research.
Project description:Terpene volatiles play an important role in the interactions among specialized pathogens and fruits. Citrus Black Spot (CBS), caused by the fungus Phyllosticta citricarpa, is associated with losses in different citrus-growing areas worldwide. The pathogen may infect the fruit for 20-24 weeks after petal fall but the typical hard spot symptoms appear when the fruit become almost mature, as consequence of fungal colonization and induction of cell lyses around essential oil cavities. D-limonene represents about 95% of total oil gland content in mature orange fruit. We have used here d-limonene synthase downregulated orange fruit generated via an antisense (AS) approach to investigate whether d-limonene decrease content in peel oil glands may affect fruit interaction with P. citricarpa compared to that of empty-vector (EV) controls. AS fruit showed enhanced resistance to the fungus compared to EV ones. Because of d-limonene decreased content, an over-accumulation of linalool and other monoterpene alcohols was found in AS compared to EV fruit. A global gene expression analysis at 2h and 8d after inoculation with P. citricarpa revealed activation of defence responses in AS fruit, via the upregulation of different PR genes, likely due to the enhanced constitutive accumulation of linalool and other alcohols. When assayed in vitro and in vivo, the main altered terpene volatile compounds including linalool at concentrations emulating those present in AS fruit, showed strong antifungal activity. We show here that terpene engineering in fruit peels could be a promising method for developing new strategies to obtain resistance to fruit diseases.