Biology subjects

Naito, K.

Publications and source records attributed to Naito, K..

15 recordsLinked to original sources

bioRxiv2026

Selective Recognition, Covalent Linkage and Chemical Exchange of Artificial Cells through Engineered α-Hemolysin

Bottom-up synthetic biology aims not only to build individual artificial cells but also to connect them into higher-order systems that communicate with each other. Reported artificial cells communicate through partner recognition, physical connection, and chemical signaling that are typically implemented by separate molecular species. Here, we engineer the pore-forming protein -hemolysin (AH) with the SpyTag-SpyCatcher (ST-SC) pair to integrate partner recognition, covalent linkage between cells, and nanopore-mediated connection of their lumens into a single protein system. Fusion of ST or SC to AH preserved heptamer assembly and pore formation, and allowed the two heptamers (AH-ST and AH-SC) to be covalently joined. Cryo-electron microscopy resolved the resulting head-to-head 14-mer assembly at 2.20 [A]. Calcein leakage and single-channel recordings confirmed that the engineered pores remain functional. Mixing ST- and SC-displaying giant unilamellar vesicles (GUVs) resulted in partner-specific association between the two vesicle populations. Finally, photo-triggered release of a newly synthesized caged ethidium bromide (EtBr) in sender GUVs produced EtBr accumulation in receiver GUVs that required direct physical linkage between the two GUVs. This platform provides a modular route toward artificial-cell assemblies in which both connectivity and cargo exchange are programmable.

synthetic biology↗

bioRxiv2026

Repetitive sequence material shapes the earliest stages of de novo gene evolution in insects

A fundamental unresolved question in molecular evolution is how novel genes arise from noncoding DNA and become fixed within stable gene repertoires. Here, we performed comparative genomic analyses across evolutionary timescales in insects using chromosome-scale genome assemblies of two cricket species, Teleogryllus occipitalis and Tarbinskiellus portentosus. Using conservative criteria, we identified 41 de novo gene candidates derived from intergenic regions in the Te. occipitalis lineage. These genes are simple and compact, exhibit hallmarks of evolutionarily young genes, and frequently contain fragments of transposable elements and simple sequence repeats. Across insects, such repetitive sequence fragments show positional homology but lack sequence conservation in older genes, suggesting that they serve as sequence material for gene emergence during early stages of gene evolution. In contrast, insertions after gene establishment are strongly constrained. We propose a model in which stages of gene evolution are characterized by shifts in selective pressure on the incorporation of sequence material.

evolutionary biology↗

bioRxiv2025

Dissecting Agronomically Favorable Genotypes in Temperate Japonica Rice via Haplotype Analysis of a Japan-MAGIC Population

O_LICrop breeding assembles genomic variants into cultivars via crossing and selection. Phenotypic selection has improved yield and lodging tolerance but has limited genetic insights. We show how specific genomic variants and their combinations underpin advances in modern rice breeding in Japan. C_LIO_LIThrough genome-wide association study using a multi-parent advanced-generation intercross population derived from four temperate japonica cultivars, we identified 11 quantitative trait loci (QTLs) for key agronomic traits, including days to heading, shoot biomass, panicle length, and culm length under field conditions. GA20ox1, GA20ox2, and Hd1 were among the QTLs, and their natural variants were well conserved in temperate japonica cultivars bred in Japan, underscoring distinct selection pressures at these loci. C_LIO_LIBy integrating genotype data with 5-year yield-performance-evaluation trials of elite cultivars, we found that cultivars carrying multiple-copy GA20ox1 and functional Hd1, together with non-functional ga20ox2, tended to have shorter culms and higher grain yield than cultivars with multiple-copy GA20ox1, functional Hd1, and GA20ox2. This yield advantage was consistent across latitudes in Japan. C_LIO_LIThese results reveal favorable genotype combinations underlying modern japonica improvement and provide a genomic framework for breeding semi-dwarf, high-yielding cultivars adapted to temperate rice-growing regions in Asia. C_LI

genomics↗

bioRxiv2025

The demographic history, genomic variation, and transcontinental genotype-phenotype-environment map of mungbean

The breeding of mungbean, a crucial Asian legume, has been hampered by the lack of genomic resources. The International Mungbean Improvement Network (IMIN) aims to ensure global access to diverse germplasms and genomic resources. Using 780 worldwide wild and cultivated accessions, we report this species most comprehensive (pan)genomic variation, demographic history, and genotype-phenotype-environment map. Despite archaeological evidence of the earliest cultivation in South Asia, present-day wild populations only possess relict traces of shared polymorphisms with cultivars. We showed that parallel losses of black seed coats in two Vigna species were caused by the same mutational mechanism in the same gene. In large-scale cross-continent field trials, we found accessions from distant environments from the trial sites have lower performance, especially in high-heritability and high-yield sites, suggesting future breeding priority in benign conditions on accessions from similar environments. Our comprehensive genomic and trial resources facilitate future breeding success of this essential crop.

evolutionary biology↗

bioRxiv2025

Temporal orchestration of transcriptional and epigenomic programming underlying maternal embryonic diapause in a cricket model

Maternal perception of environmental conditions can direct offspring developmental trajectories, providing adaptive flexibility across taxa. In the band-legged ground cricket Dianemobius nigrofasciatus, maternal exposure to short days induces embryonic diapause at the cellular blastoderm stage in offspring. Here, we investigate molecular mechanisms underlying this transgenerational adaptation through genome assembly (1.45 Gbp) and time-series transcriptomic analyses of diapause and non-diapause eggs from 12 to 72 hours post-oviposition. Despite morphological similarity, diapause-destined eggs show early upregulation of ATP-dependent chromatin remodeling genes at 24 hours. ATAC-seq reveals reduced chromatin accessibility at neural and cell cycle-related genes. Time-series clustering identifies precocious shifts in RNA processing machinery (peaking at 24 versus 40 hours in non-diapause eggs), followed by metabolic regulation toward amino acid catabolism and gluconeogenesis sustaining long-term survival during developmental arrest. Our findings reveal diapause as actively coordinated molecular programming involving epigenetic, transcriptional, and metabolic remodeling, providing insights into transgenerational environmental adaptation.

developmental biology↗

bioRxiv2025

Comparative genomics and transcriptomics on salt tolerance of Vigna luteola

Vigna luteola, a wild legume species, shows remarkable variation in salinity tolerance across its natural habitats, with coastal populations exhibiting high tolerance and riverbank populations being sensitive. This intraspecific variation provides a valuable system for investigating the genetic basis of salt tolerance. A major QTL for salt tolerance was previously identified by crossing salt-tolerant and salt-sensitive accessions, but the responsible genes remain unknown. In this study, grafting experiments between the two accessions revealed that the root plays a primary role in salt tolerance by suppressing Na transport to the shoot. We then conducted root transcriptome analysis and identified four candidate genes located within the QTL and highly expressed under salt stress in the tolerant accession: CBL-INTERACTING PROTEIN KINASE 6 (CIPK6), CAFFEOYL SHIKIMATE ESTERASE (CSE), FCS-LIKE ZINC FINGER PROTEIN 13 (FLZ13), and DROUGHT-INDUCED 21 (DI21). Promoter analysis revealed that the CIPK6 promoter contains transcription factor binding motifs unique to the salt-tolerant accession, which may contribute to its high expression under salt stress. These findings suggest that CIPK6 is regulated by cis-regulatory differences and is the most promising candidate for the salt-tolerance QTL. The identified genes in this study provide a foundation for developing salt-tolerant crops in the future.

genomics↗

bioRxiv2024

Induced systemic resistance by the root colonization of Trichoderma atroviride is independent from the chitin-mediated signaling pathway in Arabidopsis

Beneficial root endophytic fungi induce systemic responses, growth promotion, and induced systemic resistance (ISR) in the colonized host plants. Soil application of chitin, a main component of fungal cell walls, also systemically induces disease resistance. Thus, chitin recognition and its downstream signaling pathway are supposed to mediate ISR triggered by beneficial fungi colonizing the root. This study compared systemic disease resistance and transcriptional responses induced by Trichoderma, a representative beneficial root endophytic fungus, and chitin in Arabidopsis. A significant plant growth promotion was observed under root colonization by the three tested beneficial fungi, Trichoderma atroviride, Serendipita indica, and S. vermifera. Still, only T. atroviride and S. indica triggered ISR against the necrotrophic fungal pathogen Alternaria brassicicola. Induced systemic resistance triggered by T. atroviride was compromised in the chitin-receptor mutant, while systemic resistance caused by soil application of chitin was not. Transcriptome analysis demonstrated that the chitin-regulated genes are mostly shared with those regulated by T. atroviride, but many of the latter were specific. However, the commonly enriched gene ontologies for those regulated genes indicated that T. atroviride inoculation and chitin application systemically control similar transcriptional responses, mainly associated with cell wall functions. Taken together, Trichoderma could trigger ISR primarily independently from the chitin-mediated signaling pathway; however, chitin and Trichoderma would systemically induce similar cellular functions in ISR aboveground.

plant biology↗

bioRxiv2024

Multi-layered apoplastic barrier underlying the ability of Na+ exclusion in Vigna marina

O_LISalt tolerance is important to tackle problems of soil salinization and ground water depletion. However, developing salt tolerant crops is facing difficulties due to limited potential in model plants and crop species. Thus, it is important to elucidate how coastal species, such as Vigna marina, adapt to saline environments. C_LIO_LIBy comparative transcriptome and histological analyses, this study elucidated one important aspect of how Vigna marina achieves salt exclusion and extraordinary salt tolerance. C_LIO_LIUnder salt stress, genes involved in casparian strip formation were specifically upregulated in JP247202 (V. marina). JP247202 reinforced apoplastic barrier with thick lignification in multiple layers of cells around endodermis. Also, disruption of lignification led to a dramatic increase of shoot Na+ accumulation and salt lesion in JP247202. Interestingly, despite the salt-induced apoplastic barrier, JP247202 maintained transport of essential ions including K+, Mg2+, and Ca2+. C_LIO_LIOur results revealed that lignification of multi-layered cells around endodermis was an important apoplastic barrier to the transport of Na+ to shoots in JP247202, while it did not restrict the transport of K+, Mg2+, and Ca2+. This feature, together with the ability of Na+ excretion by SOS1, enables V. marina to thrive in marine beaches. C_LI

plant biology↗

bioRxiv2024

Chromosome-level assembly of Cucumis sativus cv. 'Tokiwa' as a reference genome of Japanese cucumber

Cucumber is one of the most important vegetables in the Japanese market. To facilitate genomics-based breeding, there is a demand for reference genome of Japanese cucumber. However, although cucumber genome is relatively small, its assembly is a challenging issue because of tandem repeats comprising [~]30% ([~]100 Mbp) of the genome. To overcome, we deployed the Oxford nanopore sequencing that produces long reads with N50 length of >30 kbp. With this technology we achieved a chromosome-level assembly of cv Tokiwa, a founder line of Japanese cucumber represented with the elongated fruit shape and high-crisp texture. Compared to the existing cucumber genomes, the Tokiwa genome is 20% longer and annotated with 10% more genes. The assembly with nanopore long reads also resolved tandem repeats spanning >100 kbp, demonstrating its strength in overcoming repetitive sequences.

genomics↗

bioRxiv2024

Diurnal regulation of SOS Pathway and Sodium Excretion Underlying Salinity Tolerance of Vigna marina

Vigna marina (Barm.) Merr. is adapted to tropical marine beaches and has an outstanding tolerance to salt stress. Given there are growing demands for cultivating crops in saline soil or with saline water, it is important to understand how halophytic species are adapted to the saline environments. Here we revealed by positron emitting tracer imaging system (PETIS) that V. marina actively excretes sodium from the root during the light period but not in the dark period. The following whole genome sequencing accompanied with forward genetic study identified a QTL region harboring SOS1, encoding plasma membrane Na+/H+ antiporter, which was associated with not only salt tolerance but also ability of sodium excretion. We also found the QTL region contained a large structural rearrangement that suppressed recombination across [~]20 Mbp, fixing multiple gene loci potentially involved in salt tolerance. RNA-seq and promoter analyses revealed SOS1 in V. marina was highly expressed even without salt stress and its promoter shared common cis-regulatory motifs with those exhibiting similar expression profile. Interestingly, the cis-regulatory motifs seemed installed by a transposable element (TE) insertion. Though not identified by genetic analysis, the transcriptome data also revealed SOS2 transcription was under diurnal regulation, explaining the pattern of sodium excretion together with up-regulated expression of SOS1. Furthermore, we demonstrated that, under a condition of mild salt stress, the plants with the diurnally regulated SOS pathway outperformed those with the constitutively activated one.

plant biology↗

bioRxiv2022

Genome sequence of 12 Vigna species as a knowledge base of stress tolerance and resistance

Harnessing plant genetic resources including wild plants enables exploitation of agronomically unfavorable lands to secure food in the future. The genus Vigna, family Fabaceae, consists of many species of such kind, as they are often adapted to harsh environments including marine beach, arid sandy soil, acidic soil, limestone karst and marshes. Here we report long-read assemblies of 12 Vigna species, achieving 95% or higher BUSCO scores. The comparative analyses discovered a new class of WUSCHEL-related homeobox (WOX) transcription factor superfamily that are incorporated into LTR retrotransposons and have dramatically amplified in some species of the genus Vigna. Except WOX transcription factors, however, gene contents are highly conserved among Vigna species with few copy number variations. On the other hand, transcriptome data provided some insights that transcriptional alterations played more important roles in evolution of stress tolerance in the genus Vigna. The whole genome sequences presented in this study will facilitate understanding genetic mechanisms of stress tolerance and application for developing new crops that are adapted to unfavorable environments.

genomics↗

bioRxiv2021

Chitin-induced systemic disease resistance in rice requires both OsCERK1 and OsCEBiP and is mediated via perturbation of cell-wall biogenesis in leaves

O_LIChitin is a well-known elicitor of disease resistance whose recognition by plants is crucial to perceive fungal infections. Chitin can induce both a local immune response and a systemic disease resistance when provided as a supplement in soils. Unlike local immune responses, how chitin-induced systemic disease resistance is deployed has not been studied in detail. C_LIO_LIIn this study, we evaluated systemic disease resistance against the fungal pathogen Bipolaris oryzae by performing a transcriptome analysis and monitoring cell-wall composition in rice plants grown in chitin-supplemented soils. We also examined the local immune response to chitin by measuring the production of reactive oxygen species in leaves. C_LIO_LIChitins induced both local immune response and systemic disease resistance with differing requirements for the receptors OsCERK1 and OsCEBiP. Transcriptome analysis suggested that a perturbation in cell-wall biogenesis is involved in the induction of systemic disease resistance, an idea which was supported by the induction of disease resistance by treatment with a cellulose biosynthesis inhibitor and alterations of cell-wall composition. C_LIO_LIThese findings suggest that chitin-induced systemic disease resistance in rice is caused by a perturbation of cell-wall biogenesis in leaves through long-distance signalling after recognition of chitins by OsCERK1 and OsCEBiP. C_LI

plant biology↗

bioRxiv2019

Genetic factor for twisting legume pods identified by fine-mapping of shattering-related traits in azuki bean and yard-long bean

Legumes have evolved a unique manner of seed dispersal in that the seed pods explosively split open with helical tension generated by sclerenchyma on the endocarp. During domestication, azuki bean (Vigna angularis) and yard-long bean (Vigna unguiculata cv-gr. Sesquipedalis) have reduced or lost the sclerenchyma and lost the shattering behavior of seed pods. Here we performed fine-mapping with back-crossed populations and narrowed the candidate genomic region down to 4 kbp in azuki bean and 13 kbp in yard-long bean. Among genes located in these regions, we found MYB26 genes encoded truncated proteins in both the domesticated species. We also found in azuki bean and other legumes that MYB26 is duplicated and only the duplicated copy is expressed in seed pods. Interestingly, in Arabidopsis MYB26 is single copy and is specifically expressed in anther to initiate secondary wall thickening that is required for anther dehiscence. These facts indicated that, in legumes, MYB26 has been duplicated and acquired a new role in development of pod sclerenchyma. However, pod shattering is unfavorable phenotype for harvesting and thus has been selected against by human.

genetics↗

bioRxiv2019

Understanding patterns of abiotic and biotic stress resilience to unleash the potential of crop wild relatives for climate-smart legume breeding

Although new varieties are urgently needed for climate-smart legume production, legume breeding lags behind with cereals and underutilizes wild relatives. This paper provides insights in patterns of abiotic and biotic stress resilience of legume crops and wild relatives to enhance the use and conservation of these genetic resources for climate-smart legume breeding. We focus on Vigna, a pantropical genus with more than 88 taxa including important crops such as cowpea and mung bean. Sources of pest and disease resistance occur in more than 50 percent of the Vigna taxa, which were screened while sources of abiotic stress resilience occur in less than 20 percent of the taxa, which were screened. This difference suggests that Vigna taxa co-evolve with pests and diseases while taxa are more conservative to adapt to climatic changes and salinization. Twenty-two Vigna taxa are poorly conserved in genebanks or not at all. This germplasm is not available for legume breeding and requires urgent germplasm collecting before these taxa extirpate on farm and in the wild. Vigna taxa, which tolerate heat and drought stress are rare compared with taxa, which escape these stresses or tolerate salinity. These rare Vigna taxa should be prioritized for conservation and screening for multifunctional traits of combined abiotic and biotic stress resilience. The high presence of salinity tolerance compared with drought stress tolerance, suggests that Vigna taxa are good at developing salt-tolerant traits compared with drought-tolerant traits. Vigna taxa are therefore of high value for legume production in areas that suffer from salinization.

plant biology↗

bioRxiv2018

QTL Analysis of Domestication Syndrome in Zombi Pea (Vigna vexillata), an Underutilized Legume Crop

Zombi pea (Vigna vexillata (L.) A. Rich) is an underutilized crop belonging to the genus Vigna. Two domesticated forms of zombi pea are cultivated as crop plants; seed and tuber forms. The cultivated seed form is present in Africa, while the cultivated tuber form is present in a very limited part of Asia. Genetics of domestication have been investigated in most of cultivated Vigna crops by means of quantitative trait locus (QTL) mapping. In this study, we investigated genetics of domestication in zombi pea by QTL analysis using an F2 population of 139 plants derived from a cross between cultivated tuber form of V. vexillata (JP235863) and wild V. vexillata (AusTRCF66514). A linkage map with 11 linkage groups was constructed from this F2 population using 145 SSR, 117 RAD-seq and 2 morphological markers. Many highly segregation distorted markers were found on LGs 5, 6, 7, 8, 10 and 11. Most of the distorted markers were clustered together and all the markers on LG8 were highly distorted markers. Comparing this V. vexillata linkage map with a previous linkage map of V. vexillata and linkage maps of other four Vigna species demonstrated several macro translocations in V. vexillata. QTL analysis for 22 domestication-related traits was investigated by inclusive composite interval mapping in which 37 QTLs were identified for 18 traits; no QTL was detected for 4 traits. Number of QTLs detected in each trait ranged from 1 to 5 with an average of only 2.3. Tuber traits were controlled by five QTLs with similar effect locating on different linkage groups. Large-effect QTLs (PVE > 20%) were on LG4 (pod length), LG5 (leaf size and seed thickness), and LG7 (for seed-related traits). Comparison of domestication-related QTLs of the zombi pea with those of cowpea (Vigna unguiculata), azuki bean (Vigna angularis), mungbean (Vigna radiata) and rice bean (Vigna umbellata) revealed that there was conservation of some QTLs for seed size, pod size and leaf size between zombi pea and cowpea and that QTLs associated with seed size (weight, length, width and thickness) in each species were clustered on same linkage.

genomics↗