Subgenome evolution in allotetraploid plants

GhGASA14 regulates the flowering time of upland cotton in response to GA3

KEY MESSAGE

The silencing of GhGASA14 and the identification of superior allelic variation in its coding region indicate that GhGASA14 may positively regulate flowering and the response to GA3. Gibberellic acid-stimulated Arabidopsis (GASA), a member of the gibberellin-regulated short amino acid family, has been extensively investigated in several plant species and found to be critical for plant growth and development. However, research on this topic in cotton has been limited. In this study, we identified 38 GhGASAs that were dispersed across 18 chromosomes in upland cotton, and all of these genes had a GASA core domain. Transcriptome expression patterns and qRT-PCR results revealed that GhGASA9 and GhGASA14 exhibited upregulated expression not only in the floral organs but also in the leaves of early-maturing cultivars. The two genes were functionally characterized by virus-induced gene silencing (VIGS), and the budding and flowering times after silencing the target genes were later than those of the control (TRV:00). Compared with that in the water-treated group (MOCK), the flowering period of the different fruiting branches in the GA3-treated group was more concentrated. Interestingly, allelic variation was detected in the coding sequence of GhGASA14 between early-maturing and late-maturing accessions, and the frequency of this favorable allele was greater in high-latitude cotton cultivars than in low-latitude ones. Additionally, a significant linear relationship was observed between the expression level of GhGASA14 and flowering time among the 12 upland cotton accessions. Taken together, these results indicated that GhGASA14 may positively regulate flowering time and respond to GA3. These findings could lead to the use of valuable genetic resources for breeding early-maturing cotton cultivars in the future.

Decoding drought resilience: a comprehensive exploration of the cotton Eceriferum (CER) gene family and its role in stress adaptation

BACKGROUND

The cuticular wax serves as a primary barrier that protects plants from environmental stresses. The Eceriferum (CER) gene family is associated with wax production and stress resistance.

RESULTS

In a genome-wide identification study, a total of 52 members of the CER family were discovered in four Gossypium species: G. arboreum, G. barbadense, G. raimondii, and G. hirsutum. There were variations in the physicochemical characteristics of the Gossypium CER (GCER) proteins. Evolutionary analysis classified the identified GCERs into five groups, with purifying selection emerging as the primary evolutionary force. Gene structure analysis revealed that the number of conserved motifs ranged from 1 to 15, and the number of exons varied from 3 to 13. Closely related GCERs exhibited similar conserved motifs and gene structures. Analyses of chromosomal positions, selection pressure, and collinearity revealed numerous fragment duplications in the GCER genes. Additionally, nine putative ghr-miRNAs targeting seven G. hirsutum CER (GhCER) genes were identified. Among them, three miRNAs, including ghr-miR394, ghr-miR414d, and ghr-miR414f, targeted GhCER09A, representing the most targeted gene. The prediction of transcription factors (TFs) and the visualization of the regulatory TF network revealed interactions with GhCER genes involving ERF, MYB, Dof, bHLH, and bZIP. Analysis of cis-regulatory elements suggests potential associations between the CER gene family of cotton and responses to abiotic stress, light, and other biological processes. Enrichment analysis demonstrated a robust correlation between GhCER genes and pathways associated with cutin biosynthesis, fatty acid biosynthesis, wax production, and stress response. Localization analysis showed that most GCER proteins are localized in the plasma membrane. Transcriptome and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) expression assessments demonstrated that several GhCER genes, including GhCER15D, GhCER04A, GhCER06A, and GhCER12D, exhibited elevated expression levels in response to water deficiency stress compared to control conditions. The functional identification through virus-induced gene silencing (VIGS) highlighted the pivotal role of the GhCER04A gene in enhancing drought resistance by promoting increased tissue water retention.

CONCLUSIONS

This investigation not only provides valuable evidence but also offers novel insights that contribute to a deeper understanding of the roles of GhCER genes in cotton, their role in adaptation to drought and other abiotic stress and their potential applications for cotton improvement.

Genomic basis of seed colour in quinoa inferred from variant patterns using extreme gradient boosting

Quinoa is an agriculturally important crop species originally domesticated in the Andes of central South America. One of its most important phenotypic traits is seed colour. Seed colour variation is determined by contrasting abundance of betalains, a class of strong antioxidant and free radicals scavenging colour pigments only found in plants of the order Caryophyllales. However, the genetic basis for these pigments in seeds remains to be identified. Here we demonstrate the application of machine learning (extreme gradient boosting) to identify genetic variants predictive of seed colour. We show that extreme gradient boosting outperforms the classical genome-wide association approach. We provide re-sequencing and phenotypic data for 156 South American quinoa accessions and identify candidate genes potentially controlling betalain content in quinoa seeds. Genes identified include novel cytochrome P450 genes and known members of the betalain synthesis pathway, as well as genes annotated as being involved in seed development. Our work showcases the power of modern machine learning methods to extract biologically meaningful information from large sequencing data sets.

A chromosome-scale assembly of the quinoa genome provides insights into the structure and dynamics of its subgenomes

Quinoa (Chenopodium quinoa Willd.) is an allotetraploid seed crop with the potential to help address global food security concerns. Genomes have been assembled for four accessions of quinoa; however, all assemblies are fragmented and do not reflect known chromosome biology. Here, we use in vitro and in vivo Hi-C data to produce a chromosome-scale assembly of the Chilean accession PI 614886 (QQ74). The final assembly spans 1.326 Gb, of which 90.5% is assembled into 18 chromosome-scale scaffolds. The genome is annotated with 54,499 protein-coding genes, 96.9% of which are located on the 18 largest scaffolds. We also report an updated genome assembly for the B-genome diploid C. suecicum and use it, together with the A-genome diploid C. pallidicaule, to identify genomic rearrangements within the quinoa genome, including a large pericentromeric inversion representing 71.7% of chromosome Cq3B. Repetitive sequences comprise 65.2%, 48.6%, and 57.9% of the quinoa, C. pallidicaule, and C. suecicum genomes, respectively. Evidence suggests that the B subgenome is more dynamic and has expanded more than the A subgenome. These genomic resources will enable more accurate assessments of genome evolution within the Amaranthaceae and will facilitate future efforts to identify variation in genes underlying important agronomic traits in quinoa.

Phylogenomics of Southern European Taxa in the Ranunculus auricomus Species Complex: The Apple Doesn't Fall Far from the Tree

The taxonomic status of many Southern European taxa of the Ranunculus auricomus complex remains uncertain despite this region's proximity to the native ranges of the sexual progenitor species of the complex. We investigated whether additional sexual progenitor species are present in the Mediterranean region. Utilizing target enrichment of 736 single-copy nuclear gene regions and flow cytometry, we analyzed phylogenomic relationships, the ploidy level, and the reproductive mode in representatives of 16 populations in Southern Europe, with additional sequence data from herbarium collections. Additionally, phased sequence assemblies from suspected nothotaxa were mapped to previously described sexual progenitor species in order to determine hybrid ancestry. We found the majority of Mediterranean taxa to be tetraploid, with hybrid populations propagating primarily via apomixis. Phylogenomic analysis revealed that except for the progenitor species, the Mediterranean taxa are often polyphyletic. Most apomictic taxa showed evidence of mixed heritage from progenitor species, with certain progenitor genotypes having mapped more to the populations from adjacent geographical regions. Geographical trends were found in phylogenetic distance, roughly following an east-to-west longitudinal demarcation of the complex, with apomicts extending to the southern margins. Additionally, we observed post-hybridization divergence between the western and eastern populations of nothotaxa in Southern Europe. Our results support a classification of apomictic populations as nothotaxa, as previously suggested for Central Europe.

A multi-omic Nicotiana benthamiana resource for fundamental research and biotechnology

Nicotiana benthamiana is an invaluable model plant and biotechnology platform with a ~3 Gb allotetraploid genome. To further improve its usefulness and versatility, we have produced high-quality chromosome-level genome assemblies, coupled with transcriptome, epigenome, microRNA and transposable element datasets, for the ubiquitously used LAB strain and a related wild accession, QLD. In addition, single nucleotide polymorphism maps have been produced for a further two laboratory strains and four wild accessions. Despite the loss of five chromosomes from the ancestral tetraploid, expansion of intergenic regions, widespread segmental allopolyploidy, advanced diploidization and evidence of recent bursts of Copia pseudovirus (Copia) mobility not seen in other Nicotiana genomes, the two subgenomes of N. benthamiana show large regions of synteny across the Solanaceae. LAB and QLD have many genetic, metabolic and phenotypic differences, including disparate RNA interference responses, but are highly interfertile and amenable to genome editing and both transient and stable transformation. The LAB/QLD combination has the potential to be as useful as the Columbia-0/Landsberg errecta partnership, utilized from the early pioneering days of Arabidopsis genomics to today.

Phylogenetic Analysis of Allotetraploid Species Using Polarized Genomic Sequences

Phylogenetic analysis of polyploid hybrid species has long posed a formidable challenge as it requires the ability to distinguish between alleles of different ancestral origins in order to disentangle their individual evolutionary history. This problem has been previously addressed by conceiving phylogenies as reticulate networks, using a two-step phasing strategy that first identifies and segregates homoeologous loci and then, during a second phasing step, assigns each gene copy to one of the subgenomes of an allopolyploid species. Here, we propose an alternative approach, one that preserves the core idea behind phasing-to produce separate nucleotide sequences that capture the reticulate evolutionary history of a polyploid-while vastly simplifying its implementation by reducing a complex multistage procedure to a single phasing step. While most current methods used for phylogenetic reconstruction of polyploid species require sequencing reads to be pre-phased using experimental or computational methods-usually an expensive, complex, and/or time-consuming endeavor-phasing executed using our algorithm is performed directly on the multiple-sequence alignment (MSA), a key change that allows for the simultaneous segregation and sorting of gene copies. We introduce the concept of genomic polarization that, when applied to an allopolyploid species, produces nucleotide sequences that capture the fraction of a polyploid genome that deviates from that of a reference sequence, usually one of the other species present in the MSA. We show that if the reference sequence is one of the parental species, the polarized polyploid sequence has a close resemblance (high pairwise sequence identity) to the second parental species. This knowledge is harnessed to build a new heuristic algorithm where, by replacing the allopolyploid genomic sequence in the MSA by its polarized version, it is possible to identify the phylogenetic position of the polyploid's ancestral parents in an iterative process. The proposed methodology can be used with long-read and short-read high-throughput sequencing data and requires only one representative individual for each species to be included in the phylogenetic analysis. In its current form, it can be used in the analysis of phylogenies containing tetraploid and diploid species. We test the newly developed method extensively using simulated data in order to evaluate its accuracy. We show empirically that the use of polarized genomic sequences allows for the correct identification of both parental species of an allotetraploid with up to 97% certainty in phylogenies with moderate levels of incomplete lineage sorting (ILS) and 87% in phylogenies containing high levels of ILS. We then apply the polarization protocol to reconstruct the reticulate histories of Arabidopsis kamchatica and Arabidopsis suecica, two allopolyploids whose ancestry has been well documented. [Allopolyploidy; Arabidopsis; genomic polarization; homoeologs; incomplete lineage sorting; phasing; polyploid phylogenetics; reticulate evolution.].

Polyploid Nicotiana section Suaveolentes originated by hybridization of two ancestral Nicotiana clades

Introduction

Nicotiana section Suaveolentes is an almost all-Australian clade of allopolyploid tobacco species that emerged through hybridization between diploid relatives of the genus. In this study, we aimed to assess the phylogenetic relationship of the Suaveolentes section with several Nicotiana diploid species based on both plastidial and nuclear genes.

Methods

The Nicotiana plastome-based phylogenetic analysis representing 47 newly re-built plastid genomes suggested that an ancestor of N. section Noctiflorae is the most likely maternal donor of the Suaveolentes clade. Nevertheless, we found clear evidence of plastid recombination with an ancestor from the Sylvestres clade. We analyzed 411 maximum likelihood-based phylogenetic trees from a set of conserved nuclear diploid single copy gene families following an approach that assessed the genomic origin of each homeolog.

Results

We found that Nicotiana section Suaveolentes is monophyletic with contributions from the sections Alatae, Sylvestres, Petunioides and Noctiflorae. The dating of the divergence between these sections indicates that the Suaveolentes hybridization predates the split between Alatae/Sylvestres, and Noctiflorae/Petunioides.

Discussion

We propose that Nicotiana section Suaveolentes arose from the hybridization of two ancestral species from which the Noctiflorae/Petunioides and Alatae/Sylvestres sections are derived, with Noctiflorae the maternal parent. This study is a good example in which the use of genome wide data provided additional evidence about the origin of a complex polyploid clade.

Contribution bias of parental genomes to the hybrid lineages of black Amur bream and topmouth culter revealed by low-coverage whole-genome sequencing

Interspecific hybridization has the potential to increase animal genetic diversity, enable the introgression of advantageous genetic variation, and even create hybrid lineages. Using the low-coverage whole-genome sequencing data of black Amur bream (Megalobrama terminalis [SJ]), topmouth culter (Culter alburnus [QZ]), and their hybrid progeny, we focused on the sequence variation and contribution bias to the genomic composition of the hybrid lineages of SJ♀ × QZ♂ [ZJ] and QZ♀ × SJ♂ [FJ]. Both mash-based genetic distance analysis and variant analysis based on various reference genomes revealed that the hybrid lineages' genomes are more prone to QZ composition. Furthermore, we assess the degree of subgenomic intermixing between parents QZ and SJ in the FJ and ZJ hybrid lineages. In the Jaccard index-zero genomic area, 89.41% of the genomic region in ZJ and 90.23% in FJ are entirely from one of the parental genomes. This genomic area is primarily from QZ, regardless of FJ or ZJ. In FJ, the proportion is 55.70%; in ZJ, the proportion is 54.60%. Using the reference-free variant discovery tool, we identified two InDel markers (Both were SSR-type InDel markers) and one (T/A)-type SNP marker that displayed differences in agarose electrophoresis. Our current findings suggest that parental genomic contribution bias leads to an imbalance in the genomic composition of hybrid lineages. The genomic composition bias is connected to species but not maternal effects, giving insights into the development of vertebrate genomes shortly after hybridization.

Population genomics and subgenome evolution of the allotetraploid frog Xenopus laevis in southern Africa

Allotetraploid genomes have two distinct genomic components called subgenomes that are derived from separate diploid ancestral species. Many genomic characteristics such as gene function, expression, recombination, and transposable element mobility may differ significantly between subgenomes. To explore the possibility that subgenome population structure and gene flow may differ as well, we examined genetic variation in an allotetraploid frog-the African clawed frog (Xenopus laevis)-over the dynamic and varied habitat of its native range in southern Africa. Using reduced representation genome sequences from 91 samples from 12 localities, we found no strong evidence that population structure and gene flow differed substantially by subgenome. We then compared patterns of population structure in the nuclear genome to the mitochondrial genome using Sanger sequences from 455 samples from 183 localities. Our results provide further resolution to the geographic distribution of mitochondrial and nuclear diversity in this species and illustrate that population structure in both genomes corresponds roughly with variation in seasonal rainfall and with the topography of southern Africa.

Homoeologous exchange enables rapid evolution of tolerance to salinity and hyper-osmotic stresses in a synthetic allotetraploid wheat

The link between polyploidy and enhanced adaptation to environmental stresses could be a result of polyploidy itself harbouring higher tolerance to adverse conditions, or polyploidy possessing higher evolvability than diploids under stress conditions. Natural polyploids are inherently unsuitable to disentangle these two possibilities. Using selfed progenies of a synthetic allotetraploid wheat AT3 (AADD) along with its diploid parents, Triticum urartu TMU38 (AA) and Aegilops tauschii TQ27 (DD), we addressed the foregoing issue under abiotic salinity and hyper-osmotic (drought-like) stress. Under short duration of both stresses, euploid plants of AT3 showed intermediate tolerance of diploid parents; under life-long duration of both stresses, tolerant individuals to either stress emerged from selfed progenies of AT3, but not from comparable-sized diploid parent populations. Tolerance to both stresses were conditioned by the same two homoeologous exchanges (HEs; 2DS/2AS and 3DL/3AL), and at least one HE needed to be at the homozygous state. Transcriptomic analyses revealed that hyper-up-regulation of within-HE stress responsive genes of the A sub-genome origin is likely responsible for the dual-stress tolerant phenotypes. Our results suggest that HE-mediated inter-sub-genome rearrangements can be an important mechanism leading to adaptive evolution in allopolyploids as well as a promising target for genetic manipulation in crop improvement.

Molecular characterization, targeting and expression analysis of chloroplast and mitochondrion protein import components in Nicotiana benthamiana

Improved bioinformatics tools for annotating gene function are becoming increasingly available, but such information must be considered theoretical until further experimental evidence proves it. In the work reported here, the genes for the main components of the translocons of the outer membrane of chloroplasts (Toc) and mitochondria (Tom), including preprotein receptors and protein-conducting channels of N. benthamiana, were identified. Sequence identity searches and phylogenetic relationships with functionally annotated sequences such as those of A. thaliana revealed that N. benthamiana orthologs mainly exist as recently duplicated loci. Only a Toc34 ortholog was found (NbToc34), while Toc159 receptor family was composed of four orthologs but somewhat different from those of A. thaliana. Except for NbToc90, the rest (NbToc120, NbToc159A and NbToc159B) had a molecular weight of about 150 kDa and an acidic domain similar in length. Only two orthologs of the Tom20 receptors, NbTom20-1 and NbTom20-2, were found. The number of the Toc and Tom receptor isoforms in N. benthamiana was comparable to that previously reported in tomato and what we found in BLAST searches in other species in the genera Nicotiana and Solanum. After cloning, the subcellular localization of N. benthamiana orthologs was studied, resulting to be identical to that of A. thaliana receptors. Phenotype analysis after silencing together with relative expression analysis in roots, stems and leaves revealed that, except for the Toc and Tom channel-forming components (NbToc75 and NbTom40) and NbToc34, functional redundancy could be observed either among Toc159 or mitochondrial receptors. Finally, heterodimer formation between NbToc34 and the NbToc159 family receptors was confirmed by two alternative techniques indicating that different Toc complexes could be assembled. Additional work needs to be addressed to know if this results in a functional specialization of each Toc complex.

Genome-wide identification and expression profiling of sugar transporter genes in tobacco

Sugars are both nutrients and important signal molecules in higher plants. Sugar transporters (STs) are involved in sugar loading and unloading and facilitate sugar transport across membranes. Tobacco (Nicotiana tabacum) is a model plant and one of the most significant plants economically. In our research, 92 N. tabacum ST (NtST) genes were identified and classified into eight distinct subfamilies in the tobacco genome based on phylogenetic analysis. Exon-intron analysis revealed that each subfamily manifested closely associated gene architectural features based on a comparable number or length of exons. Tandem repetition and purifying selection were the main factors of NtST gene evolution. A search for cis-regulatory elements in the promoter sequences of the NtST gene families suggested that they are probably regulated by light, plant hormones, and abiotic stress factors. We performed a comprehensive expression study in different tissues, viarious abiotic and phytohormone stresses. The results revealed different expression patterns and the functional diversification of NtST genes. The resulting data showed that NtSFP1 was highly expressed all measured five tobacco tissues, and also regulated by the MeJA, and temperature stress. In addition, the virus-induced NibenSFP1 silencing in tobacco and detected dramatically enhanced glucose content, indicating the NtSFP1 might regulate the glucose content and involved in MeJA signaling way to response the temperature stress. In general, our findings provide useful information on understanding the roles of STs in phytohormone signaling way and abiotic stresses in N. tabacum.

PYL1- and PYL8-like ABA Receptors of Nicotiana benthamiana Play a Key Role in ABA Response in Seed and Vegetative Tissue

To face the challenges of climate change and sustainable food production, it is essential to develop crop genome editing techniques to pinpoint key genes involved in abiotic stress signaling. The identification of those prevailing abscisic acid (ABA) receptors that mediate plant-environment interactions is quite challenging in polyploid plants because of the high number of genes in the PYR/PYL/RCAR ABA receptor family. Nicotiana benthamiana is a biotechnological crop amenable to genome editing, and given the importance of ABA signaling in coping with drought stress, we initiated the analysis of its 23-member family of ABA receptors through multiplex CRISPR/Cas9-mediated editing. We generated several high-order mutants impaired in NbPYL1-like and NbPYL8-like receptors, which showed certain insensitivity to ABA for inhibition of seedling establishment, growth, and development of shoot and lateral roots as well as reduced sensitivity to the PYL1-agonist cyanabactin (CB). However, in these high-order mutants, regulation of transpiration was not affected and was responsive to ABA treatment. This reveals a robust and redundant control of transpiration in this allotetraploid plant that probably reflects its origin from the extreme habitat of central Australia.

An Eruption of LTR Retrotransposons in the Autopolyploid Genomes of Chrysanthemum nankingense (Asteraceae)

Whole genome duplication, associated with the induction of widespread genetic changes, has played an important role in the evolution of many plant taxa. All extant angiosperm species have undergone at least one polyploidization event, forming either an auto- or allopolyploid organism. Compared with allopolyploidization, however, few studies have examined autopolyploidization, and few studies have focused on the response of genetic changes to autopolyploidy. In the present study, newly synthesized C. nankingense autotetraploids (Asteraceae) were employed to characterize the genome shock following autopolyploidization. Available evidence suggested that the genetic changes primarily involved the loss of old fragments and the gain of novel fragments, and some novel sequences were potential long terminal repeat (LTR) retrotransposons. As Ty1-copia and Ty3-gypsy elements represent the two main superfamilies of LTR retrotransposons, the dynamics of Ty1-copia and Ty3-gypsy were evaluated using RT-PCR, transcriptome sequencing, and LTR retrotransposon-based molecular marker techniques. Additionally, fluorescence in situ hybridization(FISH)results suggest that autopolyploidization might also be accompanied by perturbations of LTR retrotransposons, and emergence retrotransposon insertions might show more rapid divergence, resulting in diploid-like behaviour, potentially accelerating the evolutionary process among progenies. Our results strongly suggest a need to expand the current evolutionary framework to include a genetic dimension when seeking to understand genomic shock following autopolyploidization in Asteraceae.

Genome-wide unbalanced expression bias and expression level dominance toward Brassica oleracea in artificially synthesized intergeneric hybrids of Raphanobrassica

Raphanobrassica (RrRrCrCr, 2n = 4x = 36), which is generated by distant hybridization between the maternal parent Raphanus sativus (RsRs, 2n = 2x = 18) and the paternal parent Brassica oleracea (C°C°, 2n = 2x = 18), displays intermediate silique phenotypes compared to diploid progenitors. However, the hybrid shares much more similarities in silique phenotypes with those of B. oleracea than those of R. sativus. Strikingly, the silique of Raphanobrassica is obviously split into two parts. To investigate the gene expression patterns behind these phenomena, transcriptome analysis was performed on the upper, middle, and lower sections of pods (RCsiu, RCsim, and RCsil), seeds in the upper and lower sections of siliques (RCseu and RCsel) from Raphanobrassica, whole pods (Rsi and Csi) and all seeds in the siliques (Rse and Cse) from R. sativus and B. oleracea. Transcriptome shock was observed in all five aforementioned tissues of Raphanobrassica. Genome-wide unbalanced biased expression and expression level dominance were also discovered, and both of them were toward B. oleracea in Raphanobrassica, which is consistent with the observed phenotypes. The present results reveal the global gene expression patterns of different sections of siliques of Raphanobrassica, pods, and seeds of B. oleracea and R. sativus, unraveling the tight correlation between global gene expression patterns and phenotypes of the hybrid and its parents.

Quinoa genome assembly employing genomic variation for guided scaffolding

We propose to use the natural variation between individuals of a population for genome assembly scaffolding. In today's genome projects, multiple accessions get sequenced, leading to variant catalogs. Using such information to improve genome assemblies is attractive both cost-wise as well as scientifically, because the value of an assembly increases with its contiguity. We conclude that haplotype information is a valuable resource to group and order contigs toward the generation of pseudomolecules. Quinoa (Chenopodium quinoa) has been under cultivation in Latin America for more than 7500 years. Recently, quinoa has gained increasing attention due to its stress resistance and its nutritional value. We generated a novel quinoa genome assembly for the Bolivian accession CHEN125 using PacBio long-read sequencing data (assembly size 1.32 Gbp, initial N50 size 608 kbp). Next, we re-sequenced 50 quinoa accessions from Peru and Bolivia. This set of accessions differed at 4.4 million single-nucleotide variant (SNV) positions compared to CHEN125 (1.4 million SNV positions on average per accession). We show how to exploit variation in accessions that are distantly related to establish a genome-wide ordered set of contigs for guided scaffolding of a reference assembly. The method is based on detecting shared haplotypes and their expected continuity throughout the genome (i.e., the effect of linkage disequilibrium), as an extension of what is expected in mapping populations where only a few haplotypes are present. We test the approach using Arabidopsis thaliana data from different populations. After applying the method on our CHEN125 quinoa assembly we validated the results with mate-pairs, genetic markers, and another quinoa assembly originating from a Chilean cultivar. We show consistency between these information sources and the haplotype-based relations as determined by us and obtain an improved assembly with an N50 size of 1079 kbp and ordered contig groups of up to 39.7 Mbp. We conclude that haplotype information in distantly related individuals of the same species is a valuable resource to group and order contigs according to their adjacency in the genome toward the generation of pseudomolecules.