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April 21, 2020  |  

The smut fungus Ustilago esculenta has a bipolar mating system with three idiomorphs larger than 500?kb.

Zizania latifolia Turcz., which is mainly distributed in Asia, has had a long cultivation history as a cereal and vegetable crop. On infection with the smut fungus Ustilago esculenta, Z. latifolia becomes an edible vegetable, water bamboo. Two main cultivars, with a green shell and red shell, are cultivated for commercial production in Taiwan. Previous studies indicated that cultivars of Z. latifolia may be related to the infected U. esculenta isolates. However, related research is limited. The infection process of the corn smut fungus Ustilago maydis is coupled with sexual development and under control of the mating type locus. Thus, we aimed to use the knowledge of U. maydis to reveal the mating system of U. esculenta. We collected water bamboo samples and isolated 145 U. esculenta strains from Taiwan’s major production areas. By using PCR and idiomorph screening among meiotic offspring and field isolates, we identified three idiomorphs of the mating type locus and found no sequence recombination between them. Whole-genome sequencing (Illumina and PacBio) suggested that the mating system of U. esculenta was bipolar. Mating type locus 1 (MAT-1) was 552,895?bp and contained 44% repeated sequences. Sequence comparison revealed that U. esculenta MAT-1 shared high gene synteny with Sporisorium reilianum and many repeats with Ustilago hordei MAT-1. These results can be utilized to further explore the genomic diversity of U. esculenta isolates and their application for water bamboo breeding. Copyright © 2019 Elsevier Inc. All rights reserved.


April 21, 2020  |  

Do the toll-like receptors and complement systems play equally important roles in freshwater adapted Dolly Varden char (Salvelinus malma)?

Unlike the normal anadromous lifestyle, Chinese native Dolly Varden char (Salvelinus malma) is locked in land and lives in fresh water lifetime. To explore the effect of freshwater adaption on its immune system, we constructed a pooled cDNA library of hepatopancreas and spleen of Chinese freshwater Dolly Varden char (S. malma). A total of 27,829 unigenes were generated from 31,233 high-quality transcripts and 17,670 complete open reading frames (ORF) were identified. Totally 25,809 unigenes were successfully annotated and it classified more native than adaptive immunity-associated genes, and more genes involved in toll-like receptor signal pathway than those in complement and coagulation cascades (51 vs 3), implying the relative more important role of toll-like receptors than the complement system under bacterial injection for the freshwater Dolly Varden char. These huge different numbers of TLR and complement system identified in freshwater Dolly Varden char probably caused by distinct evolution pressure patterns between fish TLR and complement system, representative by TLR3 and TLR5 as well as C4 and C6, respectively, which were under purifying and positively selecting pressure, respectively. Further seawater adaptation experiment and the comparison study with our library will no doubt be helpful to elucidate the effect of freshwater adaption of Chinese native Dolly Varden char on its immune system.Copyright © 2018 Elsevier Ltd. All rights reserved.


April 21, 2020  |  

Mitochondrial DNA and their nuclear copies in the parasitic wasp Pteromalus puparum: A comparative analysis in Chalcidoidea.

Chalcidoidea (chalcidoid wasps) are an abundant and megadiverse insect group with both ecological and economical importance. Here we report a complete mitochondrial genome in Chalcidoidea from Pteromalus puparum (Pteromalidae). Eight tandem repeats followed by 6 reversed repeats were detected in its 3308?bp control region. This long and complex control region may explain failures of amplifying and sequencing of complete mitochondrial genomes in some chalcidoids. In addition to 37 typical mitochondrial genes, an extra identical isoleucine tRNA (trnI) was detected at the opposite end of the control region. This recent mitochondrial gene duplication indicates that gene arrangements in chalcidoids are ongoing. A comparison among available chalcidoid mitochondrial genomes reveals rapid gene order rearrangements overall and high protein substitution rates in most chalcidoid taxa. In addition, we identified 24 nuclear sequences of mitochondrial origin (NUMTs) in P. puparum, summing up to 9989?bp, with 3617?bp of these NUMTs originating from mitochondrial coding regions. NUMTs abundance in P. puparum is only one-twelfth of that in its relative, Nasonia vitripennis. Based on phylogenetic analysis, we provide evidence that a faster nuclear degradation rate contributes to the reduced NUMT numbers in P. puparum. Overall, our study shows unusually high rates of mitochondrial evolution and considerable variation in NUMT accumulation in Chalcidoidea. Copyright © 2018. Published by Elsevier B.V.


April 21, 2020  |  

Finding Nemo’s Genes: A chromosome-scale reference assembly of the genome of the orange clownfish Amphiprion percula.

The iconic orange clownfish, Amphiprion percula, is a model organism for studying the ecology and evolution of reef fishes, including patterns of population connectivity, sex change, social organization, habitat selection and adaptation to climate change. Notably, the orange clownfish is the only reef fish for which a complete larval dispersal kernel has been established and was the first fish species for which it was demonstrated that antipredator responses of reef fishes could be impaired by ocean acidification. Despite its importance, molecular resources for this species remain scarce and until now it lacked a reference genome assembly. Here, we present a de novo chromosome-scale assembly of the genome of the orange clownfish Amphiprion percula. We utilized single-molecule real-time sequencing technology from Pacific Biosciences to produce an initial polished assembly comprised of 1,414 contigs, with a contig N50 length of 1.86 Mb. Using Hi-C-based chromatin contact maps, 98% of the genome assembly were placed into 24 chromosomes, resulting in a final assembly of 908.8 Mb in length with contig and scaffold N50s of 3.12 and 38.4 Mb, respectively. This makes it one of the most contiguous and complete fish genome assemblies currently available. The genome was annotated with 26,597 protein-coding genes and contains 96% of the core set of conserved actinopterygian orthologs. The availability of this reference genome assembly as a community resource will further strengthen the role of the orange clownfish as a model species for research on the ecology and evolution of reef fishes. © 2018 The Authors. Molecular Ecology Resources Published by John Wiley & Sons Ltd.


April 21, 2020  |  

Mitochondrial genome characterization of Melipona bicolor: Insights from the control region and gene expression data.

The stingless bee Melipona bicolor is the only bee in which true polygyny occurs. Its mitochondrial genome was first sequenced in 2008, but it was incomplete and no information about its transcription was known. We combined short and long reads of M. bicolor DNA with RNASeq data to obtain insights about mitochondrial evolution and gene expression in bees. The complete genome has 15,001?bp, including a control region of 255?bp that contains all conserved structures described in honeybees with the highest AT content reported so far for bees (98.1%), displaying a compact but functional region. Gene expression control is similar to other insects however unusual patterns of expression may suggest the existence of different isoforms for the mitochondrially encoded 12S rRNA. Results reveal unique and shared features of the mitochondrial genome in terms of sequence evolution and gene expression making M. bicolor an interesting model to study mitochondrial genomic evolution. Copyright © 2019 Elsevier B.V. All rights reserved.


April 21, 2020  |  

Microsatellite marker set for genetic diversity assessment of primitive Chitala chitala (Hamilton, 1822) derived through SMRT sequencing technology.

In present study, single molecule-real time sequencing technology was used to obtain a validated set of microsatellite markers for application in population genetics of the primitive fish, Chitala chitala. Assembly of circular consensus sequencing reads resulted into 1164 sequences which contained 2005 repetitive motifs. A total of 100 sequences were used for primer designing and amplification yielded a set of 28 validated polymorphic markers. These loci were used to genotype n?=?72 samples from three distant riverine populations of India, namely Son, Satluj and Brahmaputra, for determining intraspecific genetic variation. The microsatellite loci exhibited high level of polymorphism with PIC values ranging from 0.281 to 0.901. The genetic parameters revealed that mean heterozygosity ranged from 0.6802 to 0.6826 and the populations were found to be genetically diverse (Fst 0.03-0.06). This indicated the potential application of these microsatellite marker set that can used for stock characterization of C. chitala, in the wild. These newly developed loci were assayed for cross transferability in another notopterid fish, Notopterus notopterus.


April 21, 2020  |  

The red bayberry genome and genetic basis of sex determination.

Morella rubra, red bayberry, is an economically important fruit tree in south China. Here, we assembled the first high-quality genome for both a female and a male individual of red bayberry. The genome size was 313-Mb, and 90% sequences were assembled into eight pseudo chromosome molecules, with 32 493 predicted genes. By whole-genome comparison between the female and male and association analysis with sequences of bulked and individual DNA samples from female and male, a 59-Kb region determining female was identified and located on distal end of pseudochromosome 8, which contains abundant transposable element and seven putative genes, four of them are related to sex floral development. This 59-Kb female-specific region was likely to be derived from duplication and rearrangement of paralogous genes and retained non-recombinant in the female-specific region. Sex-specific molecular markers developed from candidate genes co-segregated with sex in a genetically diverse female and male germplasm. We propose sex determination follow the ZW model of female heterogamety. The genome sequence of red bayberry provides a valuable resource for plant sex chromosome evolution and also provides important insights for molecular biology, genetics and modern breeding in Myricaceae family. © 2018 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.


April 21, 2020  |  

RADAR-seq: A RAre DAmage and Repair sequencing method for detecting DNA damage on a genome-wide scale.

RAre DAmage and Repair sequencing (RADAR-seq) is a highly adaptable sequencing method that enables the identification and detection of rare DNA damage events for a wide variety of DNA lesions at single-molecule resolution on a genome-wide scale. In RADAR-seq, DNA lesions are replaced with a patch of modified bases that can be directly detected by Pacific Biosciences Single Molecule Real-Time (SMRT) sequencing. RADAR-seq enables dynamic detection over a wide range of DNA damage frequencies, including low physiological levels. Furthermore, without the need for DNA amplification and enrichment steps, RADAR-seq provides sequencing coverage of damaged and undamaged DNA across an entire genome. Here, we use RADAR-seq to measure the frequency and map the location of ribonucleotides in wild-type and RNaseH2-deficient E. coli and Thermococcus kodakarensis strains. Additionally, by tracking ribonucleotides incorporated during in vivo lagging strand DNA synthesis, we determined the replication initiation point in E. coli, and its relation to the origin of replication (oriC). RADAR-seq was also used to map cyclobutane pyrimidine dimers (CPDs) in Escherichia coli (E. coli) genomic DNA exposed to UV-radiation. On a broader scale, RADAR-seq can be applied to understand formation and repair of DNA damage, the correlation between DNA damage and disease initiation and progression, and complex biological pathways, including DNA replication.Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.


April 21, 2020  |  

Complete chloroplast genome sequence of Hedychium coronarium

The first complete chloroplast genome of Hedychium coronarium (Zingiberaceae) was reported in this study. The H. coronarium chloroplast genome was 163,949bp in length and comprised a pair of inverted repeat (IR) regions of 29,780bp each, a large single-copy (LSC) region of 88,581bp and a small single-copy (SSC) region of 15,808bp. It encoded 141 genes, including 87 protein-coding genes (79 PCG species), 46 tRNA genes (28 tRNA species), and eight rRNA genes (four rRNA species). The nucleotide composition was asymmetric (31.68% A, 18.35% C, 17.74% G, 32.23% T) with an overall AT content of 63.92%. Phylogenetic analysis showed that H. coronarium was classified into a monophyletic group within the genus Hedychium in family Zingiberaceae.


April 21, 2020  |  

Complete mitochondrial genome of Hemiptelea davidii (Ulmaceae) and phylogenetic analysis

Hemiptelea davidii (Hance) Planch is a potential valuable forest tree in arid sandy environments. Here, the complete mitochondrial genome of H. davidii was assembled using a combination of the PacBio Sequel data and the Illumina Hiseq data. The mitochondrial genome is 460,941bp in length, including 37 protein-coding genes, 19 tRNA genes, and three rRNA genes. The GC content of the whole mito- chondrial genome is 44.84%. Phylogenetic analyses indicated that H. davidii is close with Cannabis and Morus species.


April 21, 2020  |  

Complete chloroplast genome of the plant Stahlianthus Involucratus (Zingiberaceae)

The first complete chloroplast genome of Stahlianthus involucratus (Zingiberaceae) was reported in this study. The S. involucratus chloroplast genome was 163,300bp in length and consisted of one large sin- gle copy (LSC) region of 87,498bp, one small single copy (SSC) region of 15,568bp, and a pair of inverted repeat (IR) regions 30,117bp. It encoded 141 genes, including 87 protein-coding genes (79 PCG species), 46 tRNA genes (28 tRNA species) and 8 rRNA genes (4 rRNA species). The phylogenetic analysis based on single nucleotide polymorphisms strongly supported that S. involucratus, Curcuma roscoeana and Curcuma longa formed a cluster in group CurcumaII within family Zingiberaceae.


April 21, 2020  |  

A systematic review of the Trypanosoma cruzi genetic heterogeneity, host immune response and genetic factors as plausible drivers of chronic chagasic cardiomyopathy.

Chagas disease is a complex tropical pathology caused by the kinetoplastid Trypanosoma cruzi. This parasite displays massive genetic diversity and has been classified by international consensus in at least six Discrete Typing Units (DTUs) that are broadly distributed in the American continent. The main clinical manifestation of the disease is the chronic chagasic cardiomyopathy (CCC) that is lethal in the infected individuals. However, one intriguing feature is that only 30-40% of the infected individuals will develop CCC. Some authors have suggested that the immune response, host genetic factors, virulence factors and even the massive genetic heterogeneity of T. cruzi are responsible of this clinical pattern. To date, no conclusive data support the reason why a few percentages of the infected individuals will develop CCC. Therefore, we decided to conduct a systematic review analysing the host genetic factors, immune response, cytokine production, virulence factors and the plausible association of the parasite DTUs and CCC. The epidemiological and clinical implications are herein discussed.


April 21, 2020  |  

Complete chloroplast genome sequence of Amomum villosum

The first complete chloroplast genome of Amomum villosum (Zingiberaceae) was reported in this study. The A. villosum genome was 163,608bp in length, and comprised a pair of inverted repeat (IR) regions of 29,820bp each, a large single-copy (LSC) region of 88,680bp, and a small single-copy (SSC) region of 15,288bp. It encoded 141 genes, including 87 protein-coding genes (79 PCG species), 46 tRNA genes (28 tRNA species), and 8 rRNA genes (4 rRNA species). The overall AT content was 63.92%. Phylogenetic analysis showed that A. villosum was closely related to two species Amomum kravanh and Amomum compactum within the genus Amomum in family Zingiberaceae.


April 21, 2020  |  

Complete chloroplast genome sequence of Carthamus tinctorius L. from PacBio Sequel Platform

Carthamus tinctorius L, also known as safflower, is an important oil crop planted worldwide. The com- plete chloroplast (cp) genome was reported in this study using the PacBio Sequel Platform. The cp genome with a total size of 152,963bp consisted of two inverted repeats (25,128bp) separated by a large single-copy region (84,124bp) and a small single-copy region (18,583bp). Further annotation revealed the cp genome contains 112 genes, including 79 protein-coding genes, 29 tRNA genes, and 4 rRNA genes. The information of the cp genome will be useful for investigation of evolution and molecular breeding of safflower in the future.


April 21, 2020  |  

The complete mitochondrial genome sequence of Schisandra chinensis (Austrobaileyales: Schisandraceae)

Chinese magnolia vine (Schisandra chinensis) is an economically important oriental medicinal plant that belongs to the Schisandraceae family. The complete mitochondrial genome sequence of S. chinensis was 946,141bp in length. A total of 45 genes was annotated, including 30 protein-coding genes, 12 tRNA genes, and 3 rRNA genes. A phylogenetic tree based on the mitochondrial genome demonstrated that S. chinensis was most closely related to Schisandra sphenanthera of the Schisandraceae family.


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