scholarly journals Chromosome-level genome assembly of a triploid poplar Populus alba ’Berolinensis’

Author(s):  
Song Chen ◽  
Yue Yu ◽  
Xinyu Wang ◽  
Sui Wang ◽  
Tianjiao Zhang ◽  
...  

Related studies have provided significant insights into polyploid breeding in recent years, but limited research was focused on trees. The genomic information for the growth and response to abiotic stress in polyploidy trees is still largely unknown. Populus alba ’Berolinensis’, also named “Yinzhong poplar”, is a triploid poplar in the northeast of China. This hybrid triploid poplar is widely used as landscape ornamentals in urban areas because of its fast growth and high tolerance to abiotic stress. As an artificially synthesized male allotriploid hybrid, the three monoploid genomes of P. alba ’Berolinensis’ originated from different poplar species, so it is the desired material for studying polyploidy genomic collaboration mechanisms. Therefore, we intensively studied the allelic genomic collaboration mechanism in P. alba ’Berolinensis’. This study generated a high-quality chromosome-level genome assembly for the P. alba ’Berolinensis’ consisting of 19 allelic chromosomes. Its three monoploid chromosomes are polymorphic with an average of 42.22 variant sites per allelic gene locus. Meanwhile, we found that stress related genes such as RD22 and LEA7 exhibited structure variations. The above information has all been deployed to our polyploid genome online analysis website TreeGenomes (https://www.treegenomes.com). These polyploid genomic related resources will provide critical foundations for the molecular breeding of P. alba ’Berolinensis’ and help us uncover the allopolyploidization effects on the resistance and traits of polyploidy species deeper in the future.

2019 ◽  
Author(s):  
Yongshuang Xiao ◽  
Zhizhong Xiao ◽  
Daoyuan Ma ◽  
Chenxi Zhao ◽  
Lin Liu ◽  
...  

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Guifang Lin ◽  
Cheng He ◽  
Jun Zheng ◽  
Dal-Hoe Koo ◽  
Ha Le ◽  
...  

Abstract Background The maize inbred line A188 is an attractive model for elucidation of gene function and improvement due to its high embryogenic capacity and many contrasting traits to the first maize reference genome, B73, and other elite lines. The lack of a genome assembly of A188 limits its use as a model for functional studies. Results Here, we present a chromosome-level genome assembly of A188 using long reads and optical maps. Comparison of A188 with B73 using both whole-genome alignments and read depths from sequencing reads identify approximately 1.1 Gb of syntenic sequences as well as extensive structural variation, including a 1.8-Mb duplication containing the Gametophyte factor1 locus for unilateral cross-incompatibility, and six inversions of 0.7 Mb or greater. Increased copy number of carotenoid cleavage dioxygenase 1 (ccd1) in A188 is associated with elevated expression during seed development. High ccd1 expression in seeds together with low expression of yellow endosperm 1 (y1) reduces carotenoid accumulation, accounting for the white seed phenotype of A188. Furthermore, transcriptome and epigenome analyses reveal enhanced expression of defense pathways and altered DNA methylation patterns of the embryonic callus. Conclusions The A188 genome assembly provides a high-resolution sequence for a complex genome species and a foundational resource for analyses of genome variation and gene function in maize. The genome, in comparison to B73, contains extensive intra-species structural variations and other genetic differences. Expression and network analyses identify discrete profiles for embryonic callus and other tissues.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Amit Rai ◽  
Hideki Hirakawa ◽  
Ryo Nakabayashi ◽  
Shinji Kikuchi ◽  
Koki Hayashi ◽  
...  

AbstractPlant genomes remain highly fragmented and are often characterized by hundreds to thousands of assembly gaps. Here, we report chromosome-level reference and phased genome assembly of Ophiorrhiza pumila, a camptothecin-producing medicinal plant, through an ordered multi-scaffolding and experimental validation approach. With 21 assembly gaps and a contig N50 of 18.49 Mb, Ophiorrhiza genome is one of the most complete plant genomes assembled to date. We also report 273 nitrogen-containing metabolites, including diverse monoterpene indole alkaloids (MIAs). A comparative genomics approach identifies strictosidine biogenesis as the origin of MIA evolution. The emergence of strictosidine biosynthesis-catalyzing enzymes precede downstream enzymes’ evolution post γ whole-genome triplication, which occurred approximately 110 Mya in O. pumila, and before the whole-genome duplication in Camptotheca acuminata identified here. Combining comparative genome analysis, multi-omics analysis, and metabolic gene-cluster analysis, we propose a working model for MIA evolution, and a pangenome for MIA biosynthesis, which will help in establishing a sustainable supply of camptothecin.


Author(s):  
Hai‐Jian Huang ◽  
Yu‐Xuan Ye ◽  
Zhuang‐Xin Ye ◽  
Xiao‐Tian Yan ◽  
Xin Wang ◽  
...  

2015 ◽  
Vol 65 (1) ◽  
pp. 85-102 ◽  
Author(s):  
Akira Kikuchi ◽  
Huu Duc Huynh ◽  
Tsukasa Endo ◽  
Kazuo Watanabe

2019 ◽  
Vol 19 (2) ◽  
pp. 485-496 ◽  
Author(s):  
Wenbo Chen ◽  
Xiaowei Yang ◽  
Guillaume Tetreau ◽  
Xiaozhao Song ◽  
Cathy Coutu ◽  
...  

Gigabyte ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Rui Zhang ◽  
Chang Li ◽  
Mengjun Yu ◽  
Xiaoyun Huang ◽  
Mengqi Zhang ◽  
...  

The humpback puffer, Tetraodon palembangensis, is a poisonous freshwater pufferfish species mainly distributed in Southeast Asia (Thailand, Laos, Malaysia and Indonesia). The humpback puffer has many interesting biological features, such as inactivity, tetrodotoxin production and body expansion. Here, we report the first chromosome-level genome assembly of the humpback puffer. The genome size is 362 Mb, with a contig N50 value of ∼1.78 Mb and a scaffold N50 value of ∼15.8 Mb. Based on this genome assembly, ∼61.5 Mb (18.11%) repeat sequences were identified, 19,925 genes were annotated, and the function of 90.01% of these genes could be predicted. Finally, a phylogenetic tree of ten teleost fish species was constructed. This analysis suggests that the humpback puffer and T. nigroviridis share a common ancestor 18.1 million years ago (MYA), and diverged from T. rubripes 45.8 MYA. The humpback puffer genome will be a valuable genomic resource to illustrate possible mechanisms of tetrodotoxin synthesis and tolerance.


2019 ◽  
Author(s):  
Ryan Bracewell ◽  
Anita Tran ◽  
Kamalakar Chatla ◽  
Doris Bachtrog

ABSTRACTThe Drosophila obscura species group is one of the most studied clades of Drosophila and harbors multiple distinct karyotypes. Here we present a de novo genome assembly and annotation of D. bifasciata, a species which represents an important subgroup for which no high-quality chromosome-level genome assembly currently exists. We combined long-read sequencing (Nanopore) and Hi-C scaffolding to achieve a highly contiguous genome assembly approximately 193Mb in size, with repetitive elements constituting 30.1% of the total length. Drosophila bifasciata harbors four large metacentric chromosomes and the small dot, and our assembly contains each chromosome in a single scaffold, including the highly repetitive pericentromere, which were largely composed of Jockey and Gypsy transposable elements. We annotated a total of 12,821 protein-coding genes and comparisons of synteny with D. athabasca orthologs show that the large metacentric pericentromeric regions of multiple chromosomes are conserved between these species. Importantly, Muller A (X chromosome) was found to be metacentric in D. bifasciata and the pericentromeric region appears homologous to the pericentromeric region of the fused Muller A-AD (XL and XR) of pseudoobscura/affinis subgroup species. Our finding suggests a metacentric ancestral X fused to a telocentric Muller D and created the large neo-X (Muller A-AD) chromosome ∼15 MYA. We also confirm the fusion of Muller C and D in D. bifasciata and show that it likely involved a centromere-centromere fusion.


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