scholarly journals The Draft Genome and Transcriptome of the Atlantic Horseshoe Crab,Limulus polyphemus

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Stephen D. Simpson ◽  
Jordan S. Ramsdell ◽  
Winsor H. Watson III ◽  
Christopher C. Chabot

The horseshoe crab,Limulus polyphemus, exhibits robust circadian and circatidal rhythms, but little is known about the molecular mechanisms underlying those rhythms. In this study, horseshoe crabs were collected during the day and night as well as high and low tides, and their muscle and central nervous system tissues were processed for genome and transcriptome sequencing, respectively. The genome assembly resulted in7.4×105contigs with N50 of 4,736, while the transcriptome assembly resulted in9.3×104contigs and N50 of 3,497. Analysis of functional completeness by the identification of putative universal orthologs suggests that the transcriptome has three times more total expected orthologs than the genome. Interestingly, RNA-Seq analysis indicated no statistically significant changes in expression level for any circadian core or accessory gene, but there was significant cycling of several noncircadian transcripts. Overall, these assemblies provide a resource to investigate theLimulusclock systems and provide a large dataset for further exploration into the taxonomy and biology of the Atlantic horseshoe crab.

2019 ◽  
Vol 26 (2) ◽  
pp. 287 ◽  
Author(s):  
Kenneth W. Able ◽  
Paola C. López-Duarte ◽  
Thomas M. Grothues ◽  
Linda Barry ◽  
Rosemarie Petrecca ◽  
...  

2019 ◽  
Author(s):  
Xue-ying Zhang ◽  
Xian-zhi Sun ◽  
Sheng Zhang ◽  
Jing-hui Yang ◽  
Fang-fang Liu ◽  
...  

Abstract Abstract Background: Aphid ( Macrosiphoniella sanbourni ) stress drastically influences the yield and quality of chrysanthemum, and grafting has been widely used to improve tolerance to biotic and abiotic stresses. However, the effect of grafting on the resistance of chrysanthemum to aphids remains unclear. Therefore, we used the RNA-Seq platform to perform a de novo transcriptome assembly to analyze the self-rooted grafted chrysanthemum ( Chrysanthemum morifolium T. 'Hangbaiju') and the grafted Artermisia-chrysanthemum (grafted onto Artemisia scoparia W.) transcription response to aphid stress. Results : The results showed that there were 1337 differentially expressed genes (DEGs), among which 680 were upregulated and 667 were downregulated, in the grafted Artemisia-chrysanthemum compared to the self-rooted grafted chrysanthemum. These genes were mainly involved in sucrose metabolism, the biosynthesis of secondary metabolites, the plant hormone signaling pathway and the plant-to-pathogen pathway. KEGG and GO enrichment analyses revealed the coordinated upregulation of these genes from numerous functional categories related to aphid stress responses. In addition, we determined the physiological indicators of chrysanthemum under aphid stress, and the results were consistent with the molecular sequencing results. All evidence indicated that grafting chrysanthemum onto A. scoparia W. upregulated aphid stress responses in chrysanthemum. Conclusion: In summary, our study presents a genome-wide transcript profile of the self-rooted grafted chrysanthemum and the grafted Artemisia-chrysanthemum and provides insights into the molecular mechanisms of C. morifolium T. in response to aphid infestation. These data will contribute to further studies of aphid tolerance and the exploration of new candidate genes for chrysanthemum molecular breeding. Key words : Chrysanthemum, Grafting, Aphid stress, Gene expression, RNA-Seq


Ecotoxicology ◽  
2016 ◽  
Vol 26 (1) ◽  
pp. 46-57 ◽  
Author(s):  
Aaron K. Bakker ◽  
Jessica Dutton ◽  
Matthew Sclafani ◽  
Nicholas Santangelo

Genetics ◽  
1986 ◽  
Vol 112 (3) ◽  
pp. 613-627
Author(s):  
Nancy C Saunders ◽  
Louis G Kessler ◽  
John C Avise

ABSTRACT Restriction site variation in mitochondrial DNA (mtDNA) of the horseshoe crab (Limulus polyphemus) was surveyed in populations ranging from New Hampshire to the Gulf Coast of Florida. MtDNA clonal diversity was moderately high, particularly in southern samples, and a major genetic "break" (nucleotide sequence divergence approximately 2%) distinguished all sampled individuals which were north vs. south of a region in northeastern Florida. The area of genotypic divergence in Limulus corresponds to a long-recognized zoogeographic boundary between warm-temperate and tropical marine faunas, and it suggests that selection pressures and/or gene flow barriers associated with water mass differences may also influence the evolution of species widely distributed across such transition zones. On the other hand, a comparison of the mtDNA divergence patterns in Limulus with computer models involving stochastic lineage extinction in species with limited gene flow demonstrates that deterministic explanations need not necessarily be invoked to account for the observations. Experiments to distinguish stochastic from deterministic possibilities are suggested. Overall, the pattern and magnitude of mtDNA differentiation in horseshoe crabs is very similar to that typically reported for freshwater and terrestrial species assayed over a comparable geographic range. Results demonstrate for the first time that, geographically, at least some continuously distributed marine organisms can show considerable mtDNA genetic differentiation.


2019 ◽  
Author(s):  
Xue-ying Zhang ◽  
Xian-zhi Sun ◽  
Sheng Zhang ◽  
Jing-hui Yang ◽  
Fang-fang Liu ◽  
...  

Abstract Abstract Background: Aphid ( Macrosiphoniella sanbourni ) stress drastically influences the yield and quality of chrysanthemum, and grafting has been widely used to improve tolerance to biotic and abiotic stresses. However, the effect of grafting on the resistance of chrysanthemum to aphids remains unclear. Therefore, we used the RNA-Seq platform to perform a de novo transcriptome assembly to analyze the self-rooted grafted chrysanthemum ( Chrysanthemum morifolium T. 'Hangbaiju') and the grafted Artermisia-chrysanthemum (grafted onto Artemisia scoparia W.) transcription response to aphid stress. Results : The results showed that there were 1337 differentially expressed genes (DEGs), among which 680 were upregulated and 667 were downregulated, in the grafted Artemisia-chrysanthemum compared to the self-rooted grafted chrysanthemum. These genes were mainly involved in sucrose metabolism, the biosynthesis of secondary metabolites, the plant hormone signaling pathway and the plant-to-pathogen pathway. KEGG and GO enrichment analyses revealed the coordinated upregulation of these genes from numerous functional categories related to aphid stress responses. In addition, we determined the physiological indicators of chrysanthemum under aphid stress, and the results were consistent with the molecular sequencing results. All evidence indicated that grafting chrysanthemum onto A. scoparia W. upregulated aphid stress responses in chrysanthemum. Conclusion: In summary, our study presents a genome-wide transcript profile of the self-rooted grafted chrysanthemum and the grafted Artemisia-chrysanthemum and provides insights into the molecular mechanisms of C. morifolium T. in response to aphid infestation. These data will contribute to further studies of aphid tolerance and the exploration of new candidate genes for chrysanthemum molecular breeding. Key words : Chrysanthemum, Grafting, Aphid stress, Gene expression, RNA-Seq


2018 ◽  
Author(s):  
Federico Vita ◽  
Amedeo Alpi ◽  
Edoardo Bertolini

AbstractThe Italian white truffle (Tuber magnatum Pico) is a gastronomic delicacy that dominates the worldwide truffle market. Despite its importance, the genomic resources currently available for this species are still limited. Here we present the first de novo transcriptome assembly of T. magnatum. Illumina RNA-seq data were assembled using a single-k-mer approach into 22,932 transcripts with N50 of 1,524 bp. Our approach allowed to predict and annotate 12,367 putative protein coding sequences, reunited in 6,723 loci. In addition, we identified 2,581 gene-based SSR markers. This work provides the first publicly available reference transcriptome for genomics and genetic studies providing insight into the molecular mechanisms underlying the biology of this important species.


Sign in / Sign up

Export Citation Format

Share Document