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Exogenous ethylene (ethephon) is widely used to induce pineapple (Ananas comosus (L.) Merr.) flowering. However, economic losses often occur due to inappropriate flower induction, which results in a lower flowering rate or no flowering, and the molecular mechanisms of flowering induction in pineapple remain unclear. To understand the global changes in gene expression during ethylene-induced pineapple flowering, we performed single-molecule real-time (SMRT) sequencing and Illumina RNA sequencing of shoot apexes or inflorescences at six time points (0 d, 8 h, 1 d, 4 d, 7 d, and 14 d after ethephon treatment). In addition, to understand the cellular and physiological processes during flowering, we also observed histological changes and measured the changes in several endogenous plant growth regulators. In this study, we obtained 29,745 polished high-quality isoforms, of which 523 had not yet been annotated within the A. comosus genome. Furthermore, 2049 alternative splicing (AS) events, 78 fusion genes, 139 long-chain non-coding RNAs (lncRNAs), and 11,184 alternative polyadenylation (APA) events were identified by SMRT sequencing. Illumina sequencing of libraries generated from these samples yielded 106.09 Gb clean reads, and the total mapped reads were 86.53%. Comparative analysis of these transcriptome databases revealed 3,690 differentially expressed genes (DEGs) between 0 d and the other time points. Candidate genes that may be involved in pineapple flowering are predicted to encode hormone-related proteins, flowering time proteins, and transcription factors. This study contributes to transcriptome information for A. comosus and will facilitate further exploration of the molecular mechanisms of ethylene-induced pineapple flowering.

Background Carex L. is one of the largest genera in the Cyperaceae family and an important vascular plant in the ecosystem. However, the genetic background of Carex is complex and the classification is not clear. In order to investigate the gene function annotation of Carex, RNA-sequencing analysis was performed. Simple sequence repeats (SSRs) were generated based on the Illumina data and then were utilized to investigate the genetic characteristics of the 79 Carex germplasms. Results In this study, 36,403 unigenes with a total length of 41,724,615 bp were obtained and annotated based on GO, KOG, KEGG, NR databases. The results provide a theoretical basis for gene function exploration. Out of 8776 SSRs, 96 pairs of primers were randomly selected. One hundred eighty polymorphic bands were amplified with a polymorphism rate of 100% based on 42 pairs of primers with higher polymorphism levels. The average band number was 4.3 per primer, the average distance value was 0.548, and the polymorphic information content was ranged from 0.133 to 0.494. The number of observed alleles (Na), effective alleles (Ne), Nei’s (1973) gene diversity (H), and the Shannon information index (I) were 2.000, 1.376, 0.243, and 0.391, respectively. NJ clustering divided into three groups and the accessions from New Zealand showed a similar genetic attribute and clustered into one group. UPGMA and PCoA analysis also revealed the same result. The analysis of molecular variance (AMOVA) revealed a superior genetic diversity within accessions than between accessions based on geographic origin cluster and NJ cluster. What’s more, the fingerprints of 79 Carex species are established in this study. Different combinations of primer pairs can be used to identify multiple Carex at one time, which overcomes the difficulties of traditional identification methods. Conclusions The transcriptomic analysis shed new light on the function categories from the annotated genes and will facilitate future gene functional studies. The genetic characteristics analysis indicated that gene flow was extensive among 79 Carex species. These markers can be used to investigate the evolutionary history of Carex and related species, as well as to serve as a guide in future breeding projects.

As an important economic shellfish, the pearl oyster, Pinctada fucata, and its larvae are an ideal model for studying molecular mechanisms of larval development in invertebrates. Larval development directly affects the quantity and quality of pearl oysters. MicroRNAs (miRNAs) may play important roles in development, but the effects of miRNA expression on P. fucata early development remain unknown. In this study, miRNA and mRNA transcriptomics of seven different P. fucata developmental stages were analyzed using Illumina RNA sequencing. A total of 329 miRNAs, including 87 known miRNAs and 242 novel miRNAs, and 33,550 unigenes, including 26,333 known genes and 7217 predicted new genes, were identified in these stages. A cluster analysis showed that the difference in the numbers of miRNAs was greatest between fertilized eggs and trochophores. In addition, the integrated mRNA transcriptome was used to predict target genes for differentially expressed miRNAs between adjacent developmental stages, and the target genes were subjected to a gene ontology enrichment analysis. Using the gene ontology annotation, 100 different expressed genes and 95 differentially expressed miRNAs were identified as part of larval development regulation. Real-time PCR was used to identify eight mRNAs and three miRNAs related to larval development. The present findings will be helpful for further clarifying the regulatory mechanisms of miRNA in invertebrate larval development.

The agent causing bud blight disease (BBD) of sweet cherry (Prunus avium), first reported in Yamagata Prefecture, Japan, in the 1990s is graft-transmissible. Previously, little cherry virus 1 (LChV-1), little cherry virus-2 (LChV-2), cherry necrotic rusty mottle virus (CNRMV), cherry green ring mottle virus (CGRMV), and/or cherry virus A (CVA) were all detected from sweet cherry trees with BBD. Here, RNA viruses in sweet cherry trees with BBD were reinvestigated by high-throughput sequencing. Illumina RNA-sequencing of double-stranded RNAs from leaves of diseased cherry trees (S1, S2, S3, and S4) indicated that all trees were infected with at least six known viruses, LChV-1, LChV-2, CNRMV, CGRMV, CVA, prune dwarf virus (PDV), and/or apple chlorotic leaf spot virus. Thus, cherry trees with BBD are all infected with multiple viruses. Moreover, we found an undescribed novel virus of the family Betaflexiviridae (tentatively named cherry virus B, ChVB) in tree S3. The complete genome sequence of ChVB comprises 8806 nt, in which five open reading frames were found similar to the viruses of the genus Foveavirus. Homology search and phylogenetic analysis indicated that ChVB is a new species of the genus Foveavirus.

Background Coccidiosis caused by Eimeria stiedae is a widespread and economically significant disease of rabbits. The lack of studies on the life-cycle development and host interactions of E. stiedae at the molecular level has hampered our understanding of its pathogenesis. Methods In this study, we present a comprehensive transcriptome landscape of E. stiedae to illustrate its dynamic development from unsporulated oocysts to sporulated oocysts, merozoites, and gametocytes, and to identify genes related to parasite-host interactions during parasitism using combined PacBio single-molecule real-time and Illumina RNA sequencing followed by bioinformatics analysis and qRT-PCR validation. Results In total, 12,582 non-redundant full-length transcripts were generated with an average length of 1808 bp from the life-cycle stages of E. stiedae. Pairwise comparisons between stages revealed 8775 differentially expressed genes (DEGs) showing highly significant description changes, which compiled a snapshot of the mechanisms underlining asexual and sexual biology of E. stiedae including oocyst sporulation between unsporulated and sporulated oocysts; merozoite replication between sporulated oocysts and merozoites; and gametophyte development and gamete generation between merozoites and gametocytes. Further, 248 DEGs were grouped into nine series clusters and five groups by expression patterns, and showed that parasite–host interaction-related genes predominated in merozoites and gametocytes and were mostly involved in steroid biosynthesis and lipid metabolism and carboxylic acid. Additionally, co-expression analyses identified genes associated with development and host invasion in unsporulated and sporulated oocysts and immune interactions during gametocyte parasitism. Conclusions This is the first study, to our knowledge, to use the global transcriptome profiles to decipher molecular changes across the E. stiedae life cycle, and these results not only provide important information for the molecular characterization of E. stiedae, but also offer valuable resources to study other apicomplexan parasites with veterinary and public significance. Graphical Abstract

Masson pine (Pinus massoniana L.) is one of the most important species for oleoresin production worldwide. However, the mechanism of oleoresin synthesis in masson pine remains poorly studied. We revealed the key differentially expressed genes associated with terpenoid biosynthesis in trees with different yields of oleoresin in different tissues (trunk xylem and needle) during different seasons (spring and autumn) based on the combined application of the SMRT full-length transcriptome and Illumina RNA sequencing under field operations. A total of 76,754 full-length non-redundant transcripts were obtained in the study. Transcriptome data were annotated with KEGG and GO, and they have been shown to be of high quality by qRT-PCR. Chloroplastic 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway and cytosolic mevalonate (MVA) pathway genes have different preferences under different conditions. Moreover, the phylogenetic analysis results revealed three classes of DXS genes with different functions. Among the tissue-specific genes, AACT1 was expressed in the trunk xylem at the highest levels, while MCS (1, 4) and HDR2 were significantly upregulated in the needle. Among stage-specific genes, DXS6 and HDS6 were expressed in the trunk xylem in August (autumn) at the highest levels. Furthermore, all of the terpene synthase (TPS) differentially expressed genes (DEGs) were clustered into the gymnosperm-specific TPS-d subfamily, including sesquiterpene synthase and diterpene synthase genes. According to the protein sequence alignment, diTPS1 and diTPS5 with three conserved active sites catalysed the synthesis of diterpene resin acids. In the low-yield oleoresin clone, diTPS (1, 5) and GGPPS (4, 6) were upregulated in the trunk xylem. The integration of the transcriptomic data indicated that the AACT, MCS, HDR, DXS, HDS, and TPS (with two conserved active sites) may play critical roles in the terpenoids biosynthesis of masson pine. The results of our study can be useful for developing an understanding of the coniferous genome and to significantly accelerate confer breeding.

The retina is a stratified layer of sensory neurons lining the posterior portion of the eye. In humans, fine detail and color vision are enabled by the macula, a central region of the retina dense in cone photoreceptors (PRs). Achromatic low light and peripheral vision are facilitated by rod PRs found with increasing density outside the macula in the peripheral retina. The outer retina is nourished by choroidal blood flow regulated by a single layer of intervening retinal pigment epithelial (RPE) cells. Existing human retinal transcriptome projects have been critical for studying aspects of retinal development and disease however, there are currently no publicly available data sets accurately describing the aging human central retina, peripheral retina, and supporting RPE/choroid. Here we used Illumina RNA sequencing (RNA-seq) analysis to characterize the mRNA transcriptome of rod and cone PR-enriched human retina as well as supporting macular RPE/choroid tissue. These data will be valuable to the vision research community for characterizing global changes in gene expression in clinically relevant ocular tissues., Measurement(s)RNA • transcriptomeTechnology Type(s)RNA sequencingFactor Type(s)type of ocular tissueSample Characteristic - OrganismHomo sapiens Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12464540

Unilateral eyestalk ablation in the female black tiger shrimp Penaeus monodon is commonly employed to induce ovarian maturation. However, the importance of complementing this practice with the provision of live feed supplement (such as polychaetes) has not been emphasized in previous studies. Indeed, it has been less emphasized that female broodstock must be fed with live feeds such as polychaetes for this practice to be effective. While the effects of eyestalk ablation have been thoroughly studied in various aspects, the synergistic effects of feeding with live feeds and the ablation have never been elucidated at a transcriptome-wide level. With recent advances in the next-generation sequencing platforms, it is now possible to investigate the effects of eyestalk ablation and live feeds at the transcriptomic levels. This study employed both short-read Illumina RNA sequencing and long-read Pacific Biosciences (PacBio) isoform sequencing (Iso-seq) to generate the first high-quality ovarian reference transcriptome in P. monodon. This novel assembly allowed us to dissect the effects of feeds and eyestalk ablation and reveal their synergistic effects at the transcriptomic level through the regulation of important genes involved in fatty acid regulation, energy production, and hormone-mediated oocyte maturation pathways. The synergistic effects between the polychaete feeding and the eyestalk ablation in the process of ovarian maturation in black tiger shrimp suggest that without having proper nutrients from the polychaetes, female broodstock might not be ready to develop its ovary. However, even with proper nutrients, the eyestalk ablation is still necessary to perhaps manipulate the female endocrine of the black tiger shrimp. These findings shed the light on molecular mechanisms and key molecular pathways that lead to successful ovarian maturation.

Xanthosine is hypothesized to increase stem cell number by promoting symmetrical cell division. Stem cells, in particular mammary stem/progenitor cells are important for gland growth and tissue repair. Molecular mechanism of xanthosine effects on mammary tissue is very limited therefore, a detailed study is warranted. The objective of this study was to evaluate transcriptomic changes in mammary gland infused/not infused with xanthosine of lactating goat. Seven primiparous Beetal goats on day 5 after kidding, were selected for the study. One gland of each goat was infused with xanthosine (TRT gland) twice daily for 3 days while the other gland did not receive any xanthosine and served as control (CON gland). Biopsy of mammary tissues was taken from TRT and CON glands, 2 days after the last day of treatment that is on day 10 after kidding. Illumina RNA-sequencing (RNA-seq) was performed for global gene expression analysis of contralateral glands. Of 382 differentially expressed genes (DEGs), 372 genes were annotated to the goat genome. Gene ontology analyses revealed majority of the DEGs to be associated with metabolic pathways (glycan and lipid metabolism), biosynthesis of antibiotics and peroxisome proliferator-activated receptor signalling pathways. These molecular pathways are either directly or indirectly involved with lipid metabolism in mammary tissue and host adaptive immune response. Expression of stem cell marker namely aldehyde dehydrogenase enzymes (ALDH1A1, ALDH3B1) were upregulated in the treatment gland. Real-time quantitative PCR (RT-qPCR) analyses of selected DEGs showed their expression profiles to be in agreement with results of RNA-seq. To our knowledge, this is the first study that describes effects of xanthosine on transcriptomic changes of mammary tissue. This information can be used further to dissect the molecular mechanisms underlying effects of xanthosine to improve production potential and udder health.

Background Unravelling the genetic basis of polymorphic characters is central to our understanding of the origins and diversification of living organisms. Recently, supergenes have been implicated in a wide range of complex polymorphisms, from adaptive colouration in butterflies and fish to reproductive strategies in birds and plants. The concept of a supergene is now a hot topic in biology, and identification of its functional elements is needed to shed light on the evolution of highly divergent adaptive traits. Here, we apply different gene expression analyses to study the supergene P that controls polymorphism of mimetic wing colour patterns in the neotropical butterfly Heliconius numata. Results We performed de novo transcriptome assembly and differential expression analyses using high-throughput Illumina RNA sequencing on developing wing discs of different H. numata morphs. Within the P interval, 30 and 17 of the 191 transcripts were expressed differentially in prepupae and day-1 pupae, respectively. Among these is the gene cortex, known to play a role in wing pattern formation in Heliconius and other Lepidoptera. Our in situ hybridization experiments confirmed the relationship between cortex expression and adult wing patterns. Conclusions This study found the majority of genes in the P interval to be expressed in the developing wing discs during the critical stages of colour pattern formation, and detect drastic changes in expression patterns in multiple genes associated with structural variants. The patterns of expression of cortex only partially recapitulate the variation in adult phenotype, suggesting that the remaining phenotypic variation could be controlled by other genes within the P interval. Although functional studies on cortex are now needed to determine its exact developmental role, our results are in accordance with the classical supergene hypothesis, whereby several genes inherited together due to tight linkage control a major developmental switch. Electronic supplementary material The online version of this article (10.1186/s13227-019-0129-2) contains supplementary material, which is available to authorized users.

Schizothorax prenanti (S. prenanti), one of the important endemic commercial fish in China, is mainly distributing in the upstream of the River Yangtze and the tributaries. The wild population is facing serious challenges of germplasm degeneration due to the overfishing, water pollution and construction of hydropower stations; therefore, it is very urgent to develop genetic resource of S. prenanti to protect the wild population. In this study, we used Illumina Hiseq2500 sequencing to develop single nucleotide polymorphism (SNP) markers in S. prenanti. From 37,785 unigenes with functional annotation, 857,535 putative SNPs were identified. Among them, 33 SNPs from immune-related genes were randomly selected and 20 loci exhibited significant polymorphisms in genotyping by Sequenom MassARRAY. As far as our best knowledge, this is the first report about the SNP markers development in S. prenanti based on Illumina RNA sequencing. These SNP markers should not only be useful for population conversation, but also for construction of genetic linkage map and economic performance improvement of S. prenanti.

Pistacia chinensis Bunge is a bioenergy tree whose seed oil has been proposed as a promising feedstock for both edible and industrial oil that can be used for biodiesel production in China. However, the transcriptomic information available for P. chinensis and the genes involved in biosynthesis of oil remain largely unknown. We used Illumina RNA-sequencing technology to sequence the complete transcriptome of P. chinensis for the first time. Over 56 million high-quality reads (5.27 Gb total) were obtained and assembled into 127,545 unigenes with a total length of 89.65 Mb and an average length of 703 bp. Among the unigenes identified, 265 were potentially involved in oil biosynthesis, including FA biosynthesis (71 unigenes), elongation (54 unigenes), desaturation (38 unigenes); triacylglycerol (TAG) and oil body (OB) biosynthesis (65 unigenes); and regulation of acyl editing during TAG biosynthesis (six unigenes). Furthermore, 31 unigenes encoding six activators and five inhibitors of TFs were associated with oil biosynthesis. Expression pattern of two desaturase enzymes were analyzed by quantitative real-time PCR (qRT-PCR) in five tissues of P. chinensis, the results shown seeds had the highest expression level. This study is the first to characterize the P. chinensis transcriptome and sequence information of those genes that are involved in oil biosynthesis could be used for metabolic engineering of pistacia to accelerate the breeding of new tree strains with better agronomic oil yields.

Pigs are important, both for agriculture and as animal models for human diseases. However, due to the lack of embryonic stem cells, the possibility of genetic modification is quite limited. To overcome this limitation, induced pluripotent stem (iPS) cells have been derived from pigs. Despite the public availability of a large number of expression datasets from mice, rats, and primates-derived iPS cells, the expression profile of pig-derived iPS cells is quite limited. Furthermore, there is no dataset focused on the profiling of pig-derived iPS cell with six reprogramming factors (Oct3/4, Sox2, Klf4, c-Myc, Lin28, and Nanog). Here, we used Illumina RNA sequencing platform to characterize the mRNA expression of four-factor derived and six-factor derived pig iPS cells. We observed that the expression levels of whole genes in our established six factors derived iPS cells and parent fibroblast, and compared with that of iPS cells with four factors in public database. These data are valuable in understanding species difference in the reprogramming process of stem cells, and could help identify the key regulating genes involved in the process.

International audience; Non-target-site resistance (NTSR) to herbicides that disrupts agricultural weed control is a worldwide concern for food security. NTSR is considered a polygenic adaptive trait driven by differential gene regulation in resistant plants. Little is known about its genetic determinism, which precludes NTSR diagnosis and evolutionary studies. We used Illumina RNA-sequencing to investigate transcriptomic differences between plants from the global major weed rye-grass sensitive or resistant to the acetolactate-synthase (ALS) inhibiting herbicide pyroxsulam. Plants were collected before and along a time-course after herbicide application. De novo transcriptome assembly yielded a resource (LOLbase) including 92,381 contigs representing potentially active transcripts that were assigned putative annotations. Early effects of ALS inhibition consistent with the literature were observed in resistant and sensitive plants, proving LOLbase data were relevant to study herbicide response. Comparison of resistant and sensitive plants identified 30 candidate NTSR contigs. Further validation using 212 plants resistant or sensitive to pyroxsulam and/or to the ALS inhibitors iodosulfuron + mesosulfuron confirmed four contigs (two cytochromes P450, one glycosyl-transferase and one glutathione-S-transferase) were NTSR markers which combined expression levels could reliably identify resistant plants. This work confirmed that NTSR is driven by differential gene expression and involves different mechanisms. It provided tools and foundation for subsequent NTSR investigations.

The genome of the cold-adapted diatom Fragilariopsis cylindrus is characterized by highly diverged haplotypes that intersperse its homozygous genome. Here, we describe how a combination of PacBio DNA and Illumina RNA sequencing can be used to resolve this complex genomic landscape locally into the highly diverged haplotypes, and how to map various environmentally controlled transcripts onto individual haplotypes. We assembled PacBio sequence data with the FALCON assembler and created a haplotype resolved annotation of the assembly using annotations of a Sanger sequenced F. cylindrus genome. RNA-seq datasets from six different growth conditions were used to resolve allele-specifc gene expression in F. cylindrus. This approach enables to study differential expression of alleles in a complex genomic landscape and provides a useful tool to study how diverged haplotypes in diploid organisms are used for adaptation and evolution to highly variable environments.

RNA sequencing transcriptome analysis using massively parallel next generation sequencing technology provides the capability to understand global changes in gene expression throughout a range of tissue samples. Development of the vertebrate retina requires complex temporal orchestration of transcriptional activation and repression. The chicken embryo (Gallus gallus) is a classic model system for studying developmental biology and retinogenesis. Existing retinal transcriptome projects have been critical to the vision research community for studying aspects of murine and human retinogenesis, however, there are currently no publicly available data sets describing the developing chicken retinal transcriptome. Here we used Illumina RNA sequencing (RNA-seq) analysis to characterize the mRNA transcriptome of the developing chicken retina in an effort to identify genes critical for retinal development in this important model organism. These data will be valuable to the vision research community for characterizing global changes in gene expression between ocular tissues and critical developmental time points during retinogenesis in the chicken retina.

Adaptation to thermal conditions in intertidal ectotherms involves tolerating and surviving frequent and often extreme variations in environmental temperatures. Modulation of gene expression plays an important role in the adaptive evolution of thermal tolerance. To understand such patterns, we investigated the thermal tolerance among three Asian populations (from Xiamen, Hong Kong, and Singapore) of the marine littorinid snail Echinolittorina malaccana and examined gene expression profiles in these populations before, during, and after heat stress using an Illumina RNA-sequencing platform. Analysis of transcriptomic changes between different conditions revealed that a proportion of the differentially expressed genes showed similar expression profiles across all three populations, including many classic molecular chaperones such as HSP70 and HSP90 that may constitute the core of the thermal stress response machinery in marine snails. Meanwhile, population-specific transcriptomic responses to heat stress were also detected. A few genes in particular showed more analogous expression profiles in the more thermally tolerant Hong Kong and Singapore populations, and these genes are likely to contribute, at least in part, to the enhanced thermal tolerance of these populations. We argue that repression of a subset of metabolic genes including several cytochrome P450 gene family members, to minimize energy expenditure and control reactive oxygen species turnover, may underpin the enhanced thermal resistance in these two populations. As such, these findings offer new insights into how marine snails cope with thermal stress and their potential evolutionary trajectory toward adapting to a warming climate.

Background Schistosoma turkestanicum is a parasite of considerable veterinary importance as an agent of animal schistosomiasis in many countries, including China. The S. turkestanicum cercariae can also infect humans, causing cercarial dermatitis in many countries and regions of the world. In spite of its significance as a pathogen of animals and humans, there is little transcriptomic and genomic data in the public databases. Methods Herein, we performed the transcriptome Illumina RNA sequencing (RNA-seq) of adult males and females of S. turkestanicum and de novo transcriptome assembly. Results Approximately 81.1 (female) and 80.5 (male) million high-quality clean reads were obtained and then 29,526 (female) and 41,346 (male) unigenes were assembled. A total of 34,624 unigenes were produced from S. turkestanicum females and males, with an average length of 878 nucleotides (nt) and N50 of 1480 nt. Of these unigenes, 25,158 (72.7 %) were annotated by blast searches against the NCBI non-redundant protein database. Among these, 21,995 (63.5 %), 22,189 (64.1 %) and 13,754 (39.7 %) of the unigenes had significant similarity in the NCBI non-redundant protein (NR), non-redundant nucleotide (NT) and Swiss-Prot databases, respectively. In addition, 3150 unigenes were identified to be expressed specifically in females and 1014 unigenes were identified to be expressed specifically in males. Interestingly, several pathways associated with gonadal development and sex maintenance were found, including the Wnt signaling pathway (103; 2 %) and progesterone-mediated oocyte maturation (77; 1.5 %). Conclusions The present study characterized and compared the transcriptomes of adult female and male blood fluke, S. turkestanicum. These results will not only serve as valuable resources for future functional genomics studies to understand the molecular aspects of S. turkestanicum, but also will provide essential information for ongoing whole genome sequencing efforts on this pathogenic blood fluke.

Background Sorghum is an important cereal crop, which requires large quantities of nitrogen fertilizer for achieving commercial yields. Identification of the genes responsible for low-N tolerance in sorghum will facilitate understanding of the molecular mechanisms of low-N tolerance, and also facilitate the genetic improvement of sorghum through marker-assisted selection or gene transformation. In this study we compared the transcriptomes of root tissues from seven sorghum genotypes having differential response to low-N stress. Results Illumina RNA-sequencing detected several common differentially expressed genes (DEGs) between four low-N tolerant sorghum genotypes (San Chi San, China17, KS78 and high-NUE bulk) and three sensitive genotypes (CK60, BTx623 and low-NUE bulk). In sensitive genotypes, N-stress increased the abundance of DEG transcripts associated with stress responses including oxidative stress and stimuli were abundant. The tolerant genotypes adapt to N deficiency by producing greater root mass for efficient uptake of nutrients. In tolerant genotypes, higher abundance of transcripts related to high affinity nitrate transporters (NRT2.2, NRT2.3, NRT2.5, and NRT2.6) and lysine histidine transporter 1 (LHT1), may suggest an improved uptake efficiency of inorganic and organic forms of nitrogen. Higher abundance of SEC14 cytosolic factor family protein transcript in tolerant genotypes could lead to increased membrane stability and tolerance to N-stress. Conclusions Comparison of transcriptomes between N-stress tolerant and sensitive genotypes revealed several common DEG transcripts. Some of these DEGs were evaluated further by comparing the transcriptomes of genotypes grown under full N. The DEG transcripts showed higher expression in tolerant genotypes could be used for transgenic over-expression in sensitive genotypes of sorghum and related crops for increased tolerance to N-stress, which results in increased nitrogen use efficiency for sustainable agriculture.

Background Antennae of fruit flies are the major organs responsible for detecting environmental volatiles, e.g., egg-laying substrates. An adult antenna contains many sensilla full of olfactory sensory neurons, where olfactory receptor (Or) genes are expressed. Each sensory neuron only expresses up to three receptors, making it difficult to estimate expression levels by conventional methods. In this study, we applied Illumina RNA sequencing (RNA-seq) to study the expression levels of Or and other genes in fly antennae. Results RNA from approximately 1,200 pairs of adult antennae from each sex of Drosophila melanogaster was used to obtain the antennal transcriptome of each sex. We detected approximately 12,000 genes expressed in antennae of either sex. The most highly expressed genes included pheromone-binding genes, transmembrane transporter genes, and sensory reception genes. Among the 61 annotated Or genes, we observed 53 and 54 genes (approximately 90%) expressed (fragments per kilobase of exon per million fragments mapped (FPKM) > 0.05) in male and female antennae, respectively; approximately 25 genes were expressed with FPKM > 15. Compared to previous studies, which extracted RNA from the whole body or head and used microarrays, antenna-specific transcriptomes obtained by RNA-seq provided more reliable estimates of gene expression levels and revealed many lowly expressed genes. Ninty-one genes, including one odorant-binding protein (Obp) gene and four Or genes, were differentially expressed between male and female antennae. These sexually biased genes were enriched on the X chromosome and showed enrichment in different gene ontology categories for male and female flies. The present and previous data together suggest that a gene family with putative immune response functions is related to pheromone detection and involved in the courtship behavior of male flies. Conclusions Tissue-specific RNA-seq is powerful for detecting lowly expressed genes. Our study provides new insight into the expression of olfactory-related genes in Drosophila antennae.

Background Rheumatoid arthritis (RA) is a chronic autoimmune-disease of unknown origin that primarily affects the joints and ultimately leads to their destruction. Growing evidence suggests that synvovial fibroblasts play important roles in the initiation and the perpetuation of RA but underlying molecular mechanisms are not understood fully. In the present study, Illumina RNA sequencing was used to profile two human normal control and two rheumatoid arthritis synvovial fibroblasts (RASFs) transcriptomes to gain insights into the roles of synvovial fibroblasts in RA. Results We found that besides known inflammatory and immune responses, other novel dysregulated networks and pathways such as Cell Morphology, Cell-To-Cell Signaling and Interaction, Cellular Movement, Cellular Growth and Proliferation, and Cellular Development, may all contribute to the pathogenesis of RA. Our study identified several new genes and isoforms not previously associated with rheumatoid arthritis. 122 genes were up-regulated and 155 genes were down-regulated by at least two-fold in RASFs compared to controls. Of note, 343 known isoforms and 561 novel isoforms were up-regulated and 262 known isoforms and 520 novel isoforms were down-regulated by at least two-fold. The magnitude of difference and the number of differentially expressed known and novel gene isoforms were not detected previously by DNA microarray. Conclusions Since the activation and proliferation of RASFs has been implicated in the pathogenesis of rheumatoid arthritis, further in-depth follow-up analysis of the transcriptional regulation reported in this study may shed light on molecular pathogenic mechanisms underlying synovial fibroblasts in arthritis and provide new leads of potential therapeutic targets.