scholarly journals Genome sequence of the wheat stem sawfly, Cephus cinctus, a primitive hymenopteran and wheat pest, illuminates evolution of hymenopteran chemoreceptors

2018 ◽  
Author(s):  
Hugh M. Robertson ◽  
Robert M. Waterhouse ◽  
Kimberly K. O. Walden ◽  
Livio Ruzzante ◽  
Maarten J. M. F. Reijnders ◽  
...  

AbstractThe wheat stem sawfly, Cephus cinctus, is a major pest of wheat and key ecological player in the grasslands of western North America. It also represents a distinctive lineage of sawflies that appeared early during the hymenopteran radiation, but after the clade of Eusymphyta sawflies that is the sister lineage of all other Hymenoptera. We present a high-quality draft genome assembly of 162 Mbp in 1,976 scaffolds with a scaffold N50 of 622 kbp. Automated gene annotation identified 11,210 protein-coding gene models and 1,307 non-coding RNA models. Thirteen percent of the assembly consists of ~58,000 transposable elements partitioned equally between Class-I and Class-II elements. Orthology analysis reveals that 86% of Cephus proteins have identifiable orthologs in other insects. Phylogenomic analysis of conserved subsets of these proteins supports the placement of the Cephidae between the Eusymphyta and the parasitic woodwasp superfamily Orussoidea. Manual annotation and phylogenetic analysis of families of odorant, gustatory, and ionotropic receptors, plus odorant binding proteins, shows that Cephus has representatives for most conserved and expanded gene lineages in the Apocrita (wasps, ants, and bees). Cephus has also maintained several insect gene lineages that have been lost from the Apocrita, most prominently the carbon dioxide receptor subfamily. Furthermore, Cephus encodes a few small lineage-specific chemoreceptor gene family expansions that might be involved in adaptations to new grasses including wheat. These comparative analyses identify gene family members likely to have been present in the hymenopteran ancestor and provide a new perspective on the evolution of the chemosensory gene repertoire.

2020 ◽  
Author(s):  
Wei Li ◽  
Cong Shi ◽  
Kui Li ◽  
Qun-jie Zhang ◽  
Yan Tong ◽  
...  

ABSTRACTBamboos are important non-timber forest plants widely distributed in the tropical and subtropical regions of Asia, Africa, America, and Pacific islands. They comprise the Bambusoideae in the grass family (Poaceae), including approximately 1,700 described species in 127 genera. In spite of the widespread uses of bamboo for food, construction and bioenergy, the gene repertoire of bamboo still remains largely unexplored. Raddia distichophylla (Schrad. ex Nees) Chase, belonging to the tribe Olyreae (Bambusoideae, Poaceae), is diploid herbaceous bamboo with only slightly lignified stems. In this study, we report a draft genome assembly of the approximately ∼589 Mb whole-genome sequence of R. distichophylla with a contig N50 length of 86.36 Kb. Repeated sequences account for ∼49.08% of the genome, of which LTR retrotransposons occupy ∼35.99% of whole genome. A total of 30,763 protein-coding genes were annotated in the R. distichophylla genome with an average transcript size of 2,887 bp. Access to this herbaceous bamboo genome sequence will provide novel insights into biochemistry, molecular-assisted breeding programs and germplasm conservation for bamboo species world-wide.


Author(s):  
Jian-Zhi Huang ◽  
Chih-Peng Lin ◽  
Ting-Chi Cheng ◽  
Ya-Wen Huang ◽  
Yi-Jung Tsai ◽  
...  

Phalaenopsis orchid is an important potted flower with high economic value around the world. We report the 3.1 Gb draft genome assembly of an important winter flowering Phalaenopsis ‘KHM190’ cultivar. We generated 89.5 Gb RNA-seq and 113 million sRNA-seq reads to use these data to identify 41,153 protein-coding genes and 188 miRNA families. We also generated a draft genome for Phalaenopsis pulcherrima ‘B8802’, a summer flowering species, via resequencing. Comparison of genome data between the two Phalaenopsis cultivars allowed the identification of 691,532 single-nucleotide polymorphisms. In this study, we reveal the key role of PhAGL6b in the regulation of flower organ development involves alternative splicing. We also show gibberellin pathways that regulate the expression of genes control flowering time during the stage in reproductive phase change induced by cool temperature. Our work should contribute a valuable resource for the flowering control, flower architecture development, and breeding of the Phalaenopsis orchids.


2021 ◽  
Author(s):  
Roger Huerlimann ◽  
Jeff A Cowley ◽  
Nicholas M Wade ◽  
Yinan Wang ◽  
Naga Kasinadhuni ◽  
...  

Shrimp are a valuable aquaculture species globally; however, disease remains a major hindrance to shrimp aquaculture sustainability and growth. Mechanisms mediated by endogenous viral elements (EVEs) have been proposed as a means by which shrimp that encounter a new virus start to accommodate rather than succumb to infection over time. However, evidence on the nature of such EVEs and how they mediate viral accommodation is limited. More extensive genomic data on Penaeid shrimp from different geographical locations should assist in exposing the diversity of EVEs. In this context, reported here is a PacBio Sequel-based draft genome assembly of an Australian black tiger shrimp (Penaeus monodon) inbred for one generation. The 1.89 Gbp draft genome is comprised of 31,922 scaffolds (N50: 496,398 bp) covering 85.9% of the projected genome size. The genome repeat content (61.8% with 30% representing simple sequence repeats) is almost the highest identified for any species. The functional annotation identified 35,517 gene models, of which 25,809 were protein-coding and 17,158 were annotated using interproscan. Scaffold scanning for specific EVEs identified an element comprised of a 9,045 bp stretch of repeated, inverted and jumbled genome fragments of Infectious hypodermal and hematopoietic necrosis virus (IHHNV) bounded by a repeated 591/590 bp host sequence. As only near complete linear ~4 kb IHHNV genomes have been found integrated in the genome of P. monodon previously, its discovery has implications regarding the validity of PCR tests designed to specifically detect such linear EVE types. The existence of conjoined inverted IHHNV genome fragments also provides a means by which hairpin dsRNAs could be expressed and processed by the shrimp RNA interference (RNAi) machinery.


2017 ◽  
Author(s):  
Timothy H Webster ◽  
Greer A. Dolby ◽  
Melissa Wilson Sayres ◽  
Kenro Kusumi

Exogenous sequence contamination presents a challenge in first-draft genomes because it can lead to non-contiguous, chimeric assembled sequences. This can mislead downstream analyses reliant on synteny, such as linkage-based analyses. Recently, the Mojave Desert Tortoise (Gopherus agassizii) draft genome was published as a resource to advance conservation efforts for the threatened species and discover more about chelonian biology and evolution. Here, we illustrate steps taken to improve the desert tortoise draft genome by removing contaminating sequences—actions that are typically carried out after the initial release of a draft genome assembly. We used information from NCBI’s Vecscreen output to remove intra-scaffold contamination and trim heading and trailing Ns. We then reordered and renamed scaffolds, and transferred the gene annotation onto this assembly. Finally, we describe the tools developed for this pipeline, freely available on Github (https://github.com/thw17/G_agassizii_reference_update), which facilitate post-assembly processing of other draft genomes. The new gopAga1.1 genome has an N50 of 251 KB, L50 of 2592 scaffolds, and its annotation retains 17,201 of the original 20,172 genes that were unaffected by the scaffold processing.


2018 ◽  
Author(s):  
Timothy H Webster ◽  
Greer A Dolby ◽  
Melissa A Wilson Sayres ◽  
Kenro Kusumi

Exogenous sequence contamination presents a challenge in first-draft genomes because it can lead to non-contiguous, chimeric assembled sequences. This can mislead downstream analyses reliant on synteny, such as linkage-based analyses. Recently, the Mojave Desert Tortoise (Gopherus agassizii) draft genome was published as a resource to advance conservation efforts for the threatened species and discover more about chelonian biology and evolution. Here, we illustrate steps taken to improve the desert tortoise draft genome by removing contaminating sequences—actions that are typically carried out after the initial release of a draft genome assembly. We used information from NCBI’s Vecscreen output to remove intra-scaffold contamination and trim heading and trailing Ns. We then reordered and renamed scaffolds, and transferred the gene annotation onto this assembly. Finally, we describe the tools developed for this pipeline, freely available on Github (https://github.com/thw17/G_agassizii_reference_update), which facilitate post-assembly processing of other draft genomes. The new gopAga1.1 genome has an N50 of 251 kb, L50 of 2592 scaffolds, and its annotation retains 17,201 of the original 20,172 genes that were unaffected by the scaffold processing.


2020 ◽  
Vol 12 (7) ◽  
pp. 1074-1079 ◽  
Author(s):  
Ruihao Shu ◽  
Jihong Zhang ◽  
Qian Meng ◽  
Huan Zhang ◽  
Guiling Zhou ◽  
...  

Abstract Ophiocordyceps sinensis (Berk.) is an entomopathogenic fungus endemic to the Qinghai-Tibet Plateau. It parasitizes and mummifies the underground ghost moth larvae, then produces a fruiting body. The fungus-insect complex, called Chinese cordyceps or “DongChongXiaCao,” is not only a valuable traditional Chinese medicine, but also a major source of income for numerous Himalayan residents. Here, taking advantage of rapid advances in single-molecule sequencing, we assembled a highly contiguous genome assembly of O. sinensis. The assembly of 23 contigs was ∼110.8 Mb with a N50 length of 18.2 Mb. We used RNA-seq and homologous protein sequences to identify 8,916 protein-coding genes in the IOZ07 assembly. Moreover, 63 secondary metabolite gene clusters were identified in the improved assembly. The improved assembly and genome features described in this study will further inform the evolutionary study and resource utilization of Chinese cordyceps.


2017 ◽  
Vol 5 (28) ◽  
Author(s):  
Su-Yeon Lee ◽  
Ji-eun An ◽  
Sun-Hwa Ryu ◽  
Myungkil Kim

ABSTRACT Polyporus brumalis is able to synthesize several sesquiterpenes during fungal growth. Using a single-molecule real-time sequencing platform, we present the 53-Mb draft genome of P. brumalis, which contains 6,231 protein-coding genes. Gene annotation and isolation support genetic information, which can increase the understanding of sesquiterpene metabolism in P. brumalis.


2019 ◽  
Author(s):  
Haley Wight ◽  
Junhui Zhou ◽  
Muzi Li ◽  
Sridhar Hannenhalli ◽  
Stephen M. Mount ◽  
...  

AbstractThe red raspberry, Rubus idaeus, is widely distributed in all temperate regions of Europe, Asia, and North America and is a major commercial fruit valued for its taste, high antioxidant and vitamin content. However, Rubus breeding is a long and slow process hampered by limited genomic and molecular resources. Genomic resources such as a complete genome sequencing and transcriptome will be of exceptional value to improve research and breeding of this high value crop. Using a hybrid sequence assembly approach including data from both long and short sequence reads, we present the first assembly of the Rubus idaeus genome (Joan J. variety). The de novo assembled genome consists of 2,145 scaffolds with a genome completeness of 95.3% and an N50 score of 638 KB. Leveraging a linkage map, we anchored 80.1% of the genome onto seven chromosomes. Using over 1 billion paired-end RNAseq reads, we annotated 35,566 protein coding genes with a transcriptome completeness score of 97.2%. The Rubus idaeus genome provides an important new resource for researchers and breeders.


Author(s):  
Qiye Li ◽  
Qunfei Guo ◽  
Yang Zhou ◽  
Huishuang Tan ◽  
Terry Bertozzi ◽  
...  

AbstractAmphibian genomes are usually challenging to assemble due to large genome size and high repeat content. The Limnodynastidae is a family of frogs native to Australia, Tasmania and New Guinea. As an anuran lineage that successfully diversified on the Australian continent, it represents an important lineage in the amphibian tree of life but lacks reference genomes. Here we sequenced and annotated the genome of the eastern banjo frog Limnodynastes dumerilii dumerilii to fill this gap. The total length of the genome assembly is 2.38 Gb with a scaffold N50 of 285.9 kb. We identified 1.21 Gb of non-redundant sequences as repetitive elements and annotated 24,548 protein-coding genes in the assembly. BUSCO assessment indicated that more than 94% of the expected vertebrate genes were present in the genome assembly and the gene set. We anticipate that this annotated genome assembly will advance the future study of anuran phylogeny and amphibian genome evolution.


GigaScience ◽  
2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Rute R da Fonseca ◽  
Alvarina Couto ◽  
Andre M Machado ◽  
Brona Brejova ◽  
Carolin B Albertin ◽  
...  

ABSTRACT Background The giant squid (Architeuthis dux; Steenstrup, 1857) is an enigmatic giant mollusc with a circumglobal distribution in the deep ocean, except in the high Arctic and Antarctic waters. The elusiveness of the species makes it difficult to study. Thus, having a genome assembled for this deep-sea–dwelling species will allow several pending evolutionary questions to be unlocked. Findings We present a draft genome assembly that includes 200 Gb of Illumina reads, 4 Gb of Moleculo synthetic long reads, and 108 Gb of Chicago libraries, with a final size matching the estimated genome size of 2.7 Gb, and a scaffold N50 of 4.8 Mb. We also present an alternative assembly including 27 Gb raw reads generated using the Pacific Biosciences platform. In addition, we sequenced the proteome of the same individual and RNA from 3 different tissue types from 3 other species of squid (Onychoteuthis banksii, Dosidicus gigas, and Sthenoteuthis oualaniensis) to assist genome annotation. We annotated 33,406 protein-coding genes supported by evidence, and the genome completeness estimated by BUSCO reached 92%. Repetitive regions cover 49.17% of the genome. Conclusions This annotated draft genome of A. dux provides a critical resource to investigate the unique traits of this species, including its gigantism and key adaptations to deep-sea environments.


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