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Background: Long non-coding RNAs (lncRNAs) are a new class of regulatory molecules with roles in diverse biological processes. While much effort has been invested in the analysis of lncRNAs from established plant models Arabidopsis, maize, and rice, almost nothing is known about lncRNAs from fruit crops, including those in the Rosaceae family., Results: Here, we present a genome-scale identification and characterization of lncRNAs from a diploid strawberry, Fragaria vesca, based on rich RNA-seq datasets from 35 different flower and fruit tissues. 5,884 Fve-lncRNAs derived from 3,862 loci were identified. These lncRNAs were carefully cataloged based on expression level and whether or not they contain repetitive sequences or generate small RNAs. About one fourth of them are termed high-confidence lncRNAs (hc-lncRNAs) because they are expressed at a level of FPKM higher than 2 and produce neither small RNAs nor contain repetitive sequence. To identify regulatory interactions between lncRNAs and their potential protein-coding (PC) gene targets, pairs of lncRNAs and PC genes with positively or negatively correlated expression trends were identified based on their expression; these pairs may be candidates of cis- or trans-acting lncRNAs and their targets. Finally, blast searches within plant species indicate that lncRNAs are not well conserved., Conclusions: Our study identifies a large number of tissue-specifically expressed lncRNAs in F. vesca, thereby highlighting their potential contributions to strawberry flower and fruit development and paving the way for future functional studies.

Background: Fragaria vesca is a low-growing, small-fruited diploid strawberry species commonly called woodland strawberry. It is native to temperate regions of Eurasia and North America and while it produces edible fruits, it is most highly useful as an experimental perennial plant system that can serve as a model for the agriculturally important Rosaceae family. A draft of the F. vesca genome sequence was published in 2011 [Nat Genet 43:223,2011]. The first generation annotation (version 1.1) were developed using GeneMark-ES+[Nuc Acids Res 33:6494,2005]which is a self-training gene prediction tool that relies primarily on the combination of ab initio predictions with mapping high confidence ESTs in addition to mapping gene deserts from transposable elements. Based on over 25 different tissue transcriptomes, we have revised the F. vesca genome annotation, thereby providing several improvements over version 1.1., Results: The new annotation, which was achieved using Maker, describes many more predicted protein coding genes compared to the GeneMark generated annotation that is currently hosted at the Genome Database for Rosaceae ( http://www.rosaceae.org/ ). Our new annotation also results in an increase in the overall total coding length, and the number of coding regions found. The total number of gene predictions that do not overlap with the previous annotations is 2286, most of which were found to be homologous to other plant genes. We have experimentally verified one of the new gene model predictions to validate our results., Conclusions: Using the RNA-Seq transcriptome sequences from 25 diverse tissue types, the re-annotation pipeline improved existing annotations by increasing the annotation accuracy based on extensive transcriptome data. It uncovered new genes, added exons to current genes, and extended or merged exons. This complete genome re-annotation will significantly benefit functional genomic studies of the strawberry and other members of the Rosaceae.

Background: Double flower domestication is of great value in ornamental plants and presents an excellent system to study the mechanism of morphological alterations by human selection. The classic ABC model provides a genetic framework underlying the control of floral organ identity and organogenesis from which key regulators have been identified and evaluated in many plant species. Recent molecular studies have underscored the importance of C-class homeotic genes, whose functional attenuation contributed to the floral diversity in various species. Cultivated Camellia japonica L. possesses several types of double flowers, however the molecular mechanism underlying their floral morphological diversification remains unclear., Results: In this study, we cloned the C-class orthologous gene CjAG in C. japonica. We analyzed the expression patterns of CjAG in wild C. japonica, and performed ectopic expression in Arabidopsis. These results revealed that CjAG shared conserved C-class function that controls stamen and carpel development. Further we analyzed the expression pattern of CjAG in two different C. japonica double-flower varieties, 'Shibaxueshi' and 'Jinpanlizhi', and showed that expression of CjAG was highly contracted in 'Shibaxueshi' but expanded in inner petals of 'Jinpanlizhi'. Moreover, detailed expression analyses of B- and C-class genes have uncovered differential patterns of B-class genes in the inner organs of 'Jinpanlizhi'., Conclusions: These results demonstrated that the contraction and expansion of CjAG expression were associated with the formation of different types of double flowers. Our studies have manifested two different trajectories of double flower domestication regarding the C-class gene expression in C. japonica.

Background: Fragaria vesca, a diploid strawberry species commonly known as the alpine or woodland strawberry, is a versatile experimental plant system and an emerging model for the Rosaceae family. An ancestral F. vesca genome contributed to the genome of the octoploid dessert strawberry (F. ×ananassa), and the extant genome exhibits synteny with other commercially important members of the Rosaceae family such as apple and peach. To provide a molecular description of floral organ and fruit development at the resolution of specific tissues and cell types, RNAs from flowers and early developmental stage fruit tissues of the inbred F. vesca line YW5AF7 were extracted and the resulting cDNA libraries sequenced using an Illumina HiSeq2000. To enable easy access as well as mining of this two-dimensional (stage and tissue) transcriptome dataset, a web-based database, the Strawberry Genomic Resource (SGR), was developed., Description: SGR is a web accessible database that contains sample description, sample statistics, gene annotation, and gene expression analysis. This information can be accessed publicly from a web-based interface at http://bioinformatics.towson.edu/strawberry/Default.aspx. The SGR website provides user friendly search and browse capabilities for all the data stored in the database. Users are able to search for genes using a gene ID or description or obtain differentially expressed genes by entering different comparison parameters. Search results can be downloaded in a tabular format compatible with Microsoft excel application. Aligned reads to individual genes and exon/intron structures are displayed using the genome browser, facilitating gene re-annotation by individual users., Conclusions: The SGR database was developed to facilitate dissemination and data mining of extensive floral and fruit transcriptome data in the woodland strawberry. It enables users to mine the data in different ways to study different pathways or biological processes during reproductive development.

Background: Single nucleotide polymorphisms (SNPs) are widely observed between individuals, ecotypes, and species, serving as an invaluable molecular marker for genetic, genomic, ecological and evolutionary studies. Although, a large number of SNP-discriminating methods are currently available, few are suited for low-throughput and low-cost applications. Here, we describe a genotyping method named Simple Allele-discriminating PCR (SAP), which is ideally suited for the small-scale genotyping and gene mapping routinely performed in small to medium research or teaching laboratories., Results: We demonstrate the feasibility and application of SAP to discriminate wild type alleles from their respective mutant alleles in Arabidopsis thaliana. Although the design principle was previously described, it is unclear if the method is technically robust, reliable, and applicable. Three primers were designed for each individual SNP or allele with two allele-discriminating forward primers (one for wild type and one for the mutant allele) and a common reverse primer. The two allele-discriminating forward primers are designed so that each incorporates one additional mismatch at the adjacent (penultimate) site from the SNP, resulting in two mismatches between the primer and its non-target template and one mismatch between the primer and its target template. The presence or absence of the wild type or the mutant allele correlates with the presence or absence of respective PCR product. The presence of both wild type-specific and mutant-specific PCR products would indicate heterozygosity. SAP is shown here to discriminate three mutant alleles (lug-3, lug-16, and luh-1) from their respective wild type alleles. In addition, the SAP principle is shown to work in conjunction with fluorophore-labeled primers, demonstrating the feasibility of applying SAP to high throughput SNP analyses., Conclusion: SAP offers an excellent alternative to existing SNP-discrimination methods such as Cleaved Amplified Polymorphic Sequence (CAPS) or derived CAPS (dCAPS). It can also be adapted for high throughput SNP analyses by incorporating fluorophore-labeled primers. SAP is reliable, cost-effective, fast, and simple, and can be applied to all organisms not limited to Arabidopsis thaliana.