Japan National Institute of Agrobiological Science

Ibaraki, Japan

Japan National Institute of Agrobiological Science

Ibaraki, Japan
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Takaiwa F.,Japan National Institute of Agrobiological Science
Human Vaccines | Year: 2011

Plant-based vaccines have advantages over conventional vaccines in terms of scalability, lack of requirement for cold chain logistics, stability, safety, cost-effectiveness and needle-free administration. In particular, when antigen is expressed in seeds, high production is possible and immunogenicity is not lost even if stocked at ambient temperature for several years. induction of immune tolerance (desensitization) to allergen is a principle strategy for controlling allergic diseases, and is generally carried out by subcutaneous injection. Seed-based oral administration offers a straightforward and inexpensive alternative approach to deliver vaccines effectively to the GALT without loss of activity. Consumption of transgenic seeds containing modified hypo-allergenic tolerogen or T-cell epitope peptides derived from allergens has no or very few severe side effects and can induce immune tolerance leading to reduction of allergen-specific IgE production, T-cell proliferation and release of histamine. suppression of allergen-specific clinical symptoms results. Thus, seed-based allergy vaccines offer an innovative and convenient allergen-specific immunotherapeutic approach as an alternative to conventional allergen-specific immunotherapy. © 2011 Landes Bioscience.

Ishibashi K.,Japan National Institute of Agrobiological Science | Ishikawa M.,Japan National Institute of Agrobiological Science
Journal of Virology | Year: 2013

The Tm-1 gene of tomato confers resistance to Tomato mosaic virus (ToMV). Tm-1 encodes a protein that binds ToMV replication proteins and inhibits the RNA-dependent RNA replication of ToMV. The replication proteins of resistance-breaking mutants of ToMV do not bind Tm-1, indicating that the binding is important for inhibition. In this study, we analyzed how Tm-1 inhibits ToMV RNA replication in a cell-free system using evacuolated tobacco protoplast extracts. In this system, ToMV RNA replication is catalyzed by replication proteins bound to membranes, and the RNA polymerase activity is unaffected by treatment with 0.5 M NaCl-containing buffer and remains associated with membranes. We show that in the presence of Tm-1, negative-strand RNA synthesis is inhibited; the replication proteins associate with membranes with binding that is sensitive to 0.5 M NaCl; the viral genomic RNA used as a translation template is not protected from nuclease digestion; and host membrane proteins TOM1, TOM2A, and ARL8 are not copurified with the membrane-bound 130K replication protein. Deletion of the polymerase read-through domain or of the 3= untranslated region (UTR) of the genome did not prevent the formation of complexes between the 130K protein and the host membrane proteins, the 0.5 M NaCl-resistant binding of the replication proteins to membranes, and the protection of the genomic RNA from nucleases. These results indicate that Tm-1 binds ToMV replication proteins to inhibit key events in replication complex formation on membranes that precede negative-strand RNA synthesis. © 2013, American Society for Microbiology.

Watanabe H.,Japan National Institute of Agrobiological Science | Tokuda G.,University of Ryukyus
Annual Review of Entomology | Year: 2010

Despite the presence of many carbohydrolytic activities in insects, their cellulolytic mechanisms are poorly understood. Whereas cellulase genes are absent from the genomes of Drosophila melanogaster or Bombyx mori, other insects such as termites produce their own cellulases. Recent studies using molecular biological techniques have brought new insights into the mechanisms by which the insects and their microbial symbionts digest cellulose in the small intestine. DNA sequences of cellulase and associated genes, as well as physiological and morphological information about the digestive systems of cellulase-producing insects, may allow the efficient use of cellulosic biomass as a sustainable energy source. © 2010 by Annual Reviews All rights reserved.

Suetsugu Y.,Japan National Institute of Agrobiological Science
G3 (Bethesda, Md.) | Year: 2013

The establishment of a complete genomic sequence of silkworm, the model species of Lepidoptera, laid a foundation for its functional genomics. A more complete annotation of the genome will benefit functional and comparative studies and accelerate extensive industrial applications for this insect. To realize these goals, we embarked upon a large-scale full-length cDNA collection from 21 full-length cDNA libraries derived from 14 tissues of the domesticated silkworm and performed full sequencing by primer walking for 11,104 full-length cDNAs. The large average intron size was 1904 bp, resulting from a high accumulation of transposons. Using gene models predicted by GLEAN and published mRNAs, we identified 16,823 gene loci on the silkworm genome assembly. Orthology analysis of 153 species, including 11 insects, revealed that among three Lepidoptera including Monarch and Heliconius butterflies, the 403 largest silkworm-specific genes were composed mainly of protective immunity, hormone-related, and characteristic structural proteins. Analysis of testis-/ovary-specific genes revealed distinctive features of sexual dimorphism, including depletion of ovary-specific genes on the Z chromosome in contrast to an enrichment of testis-specific genes. More than 40% of genes expressed in specific tissues mapped in tissue-specific chromosomal clusters. The newly obtained FL-cDNA sequences enabled us to annotate the genome of this lepidopteran model insect more accurately, enhancing genomic and functional studies of Lepidoptera and comparative analyses with other insect orders, and yielding new insights into the evolution and organization of lepidopteran-specific genes.

Nakao H.,Japan National Institute of Agrobiological Science
Developmental Biology | Year: 2012

Insect embryo segmentation is largely divided into long and short germ types. In the long germ type, each segment primordium is represented on a large embryonic rudiment of the blastoderm, and segmental patterning occurs nearly simultaneously in the syncytium. In the short germ type, however, only anterior segments are represented in the small embryonic rudiment, usually located on the egg posterior, and the rest of the segments are added sequentially from the posterior growth zone in a cellular context. The long germ type is thought to have evolved from the short germ type. It is proposed that this transition, which appears to have occurred multiple times over the course of evolution, was realized through the acquisition of a localized anterior instruction center. Here, I examined the early segmentation process in the silkmoth Bombyx mori, a lepidopteran insect, in which the mechanisms of anterior-posterior (AP) axis formation have not been well analyzed. In this insect, both the long germ and short germ features have been reported. The mRNAs for two key genes involved in insect AP axis formation, orthodenticle (Bm-otd) and caudal (Bm-cad), are localized maternally in the germ anlage, where they act as anterior and posterior instruction centers, respectively. RNAi studies indicate that, while Bm-cad affects the formation of all the even skipped (Bm-eve) stripes, there is also anterior Bm-eve stripe formation activity that involves Bm-otd. Thus, there is redundancy in Bm-eve stripe formation activity that must be coordinated. Some genetic interactions, identified either experimentally or hypothetically, are also introduced, which might enable robust AP formation in this organism. © 2012 Elsevier Inc.

Kawahara Y.,Japan National Institute of Agrobiological Science
PloS one | Year: 2012

A filamentous fungus, Magnaporthe oryzae, is a causal agent of rice blast disease, which is one of the most serious diseases affecting cultivated rice, Oryza sativa. However, the molecular mechanisms underlying both rice defense and fungal attack are not yet fully understood. Extensive past studies have characterized many infection-responsive genes in the pathogen and host plant, separately. To understand the plant-pathogen interaction comprehensively, it is valuable to monitor the gene expression profiles of both interacting organisms simultaneously in the same infected plant tissue. Although the host-pathogen interaction during the initial infection stage is important for the establishment of infection, the detection of fungal gene expression in infected leaves at the stage has been difficult because very few numbers of fungal cells are present. Using the emerging RNA-Seq technique, which has a wide dynamic range for expression analyses, we analyzed the mixed transcriptome of rice and blast fungus in infected leaves at 24 hours post-inoculation, which is the point when the primary infection hyphae penetrate leaf epidermal cells. We demonstrated that our method detected the gene expression of both the host plant and pathogen simultaneously in the same infected leaf blades in natural infection conditions without any artificial treatments. The upregulation of 240 fungal transcripts encoding putative secreted proteins was observed, suggesting that these candidates of fungal effector genes may play important roles in initial infection processes. The upregulation of transcripts encoding glycosyl hydrolases, cutinases and LysM domain-containing proteins were observed in the blast fungus, whereas pathogenesis-related and phytoalexin biosynthetic genes were upregulated in rice. Furthermore, more drastic changes in expression were observed in the incompatible interactions compared with the compatible ones in both rice and blast fungus at this stage. Our mixed transcriptome analysis is useful for the simultaneous elucidation of the tactics of host plant defense and pathogen attack.

Konno K.,Japan National Institute of Agrobiological Science
Phytochemistry | Year: 2011

Plant latex and other exudates are saps that are exuded from the points of plant damage caused either mechanically or by insect herbivory. Although many (ca. 10%) of plant species exude latex or exudates, and although the defensive roles of plant latex against herbivorous insects have long been suggested by several studies, the detailed roles and functions of various latex ingredients, proteins and chemicals, in anti-herbivore plant defenses have not been well documented despite the wide occurrence of latex in the plant kingdom. Recently, however, substantial progress has been made. Several latex proteins, including cysteine proteases and chitin-related proteins, have been shown to play important defensive roles against insect herbivory. In the mulberry (Morus spp.)-silkworm (Bombyx mori) interaction, an old and well-known model system of plant-insect interaction, plant latex and its ingredients - sugar-mimic alkaloids and defense protein MLX56 - are found to play key roles. Complicated molecular interactions between Apocynaceae species and its specialist herbivores, in which cardenolides and defense proteins in latex play key roles, are becoming more and more evident. Emerging observations suggested that plant latex, analogous to animal venom, is a treasury of useful defense proteins and chemicals that has evolved through interspecific interactions. On the other hand, specialist herbivores developed sophisticated adaptations, either molecular, physiological, or behavioral, against latex-borne defenses. The existence of various adaptations in specialist herbivores itself is evidence that latex and its ingredients function as defenses at least against generalists. Here, we review molecular and structural mechanisms, ecological roles, and evolutionary aspects of plant latex as a general defense against insect herbivory and we discuss, from recent studies, the unique characteristics of latex-borne defense systems as transport systems of defense substances are discussed based on recent studies. © 2011 Elsevier Ltd. All rights reserved.

Takaiwa F.,Japan National Institute of Agrobiological Science
Immunotherapy | Year: 2013

Rice seed provides an ideal production platform for pharmaceuticals in terms of high productivity and stability, as well as the scalability, safety and economy that are expected in plant production systems. Furthermore, these therapeutic products are bioencapsulated in protein bodies, which are seed-specific storage organelles that provide protection from digestion by gastrointestinal enzymes during delivery to the gut-associated lymphoid tissue. Thus, rice seed provides an ideal delivery system for the mucosal immune system. Oral immunotherapy using unprocessed transgenic rice seed containing therapeutic products has been demonstrated to induce effective mucosal immune tolerance and immune reactions against allergies and pathogens. © 2013 Future Medicine Ltd.

Izawa T.,Japan National Institute of Agrobiological Science
Plant, Cell and Environment | Year: 2012

For many decades, researchers have focused on the self-sustainable oscillations of plant circadian clocks, which can only be observed under artificial constant environmental conditions. However, plants have evolved under natural diurnal conditions where several major environmental cues such as light, temperature and humidity are dramatically changing and interacting with each other. Therefore, little is known about the roles of the plant circadian clock in natural field conditions. Molecular genetic analyses in Arabidopsis thaliana have revealed that some core circadian clock genes are required for the establishment of robust circadian rhythms under artificial diurnal conditions, and that others function only as self-oscillators. However, it is largely unknown yet how those robust rhythms can be obtained under natural diurnal conditions. Recently, an extensive time-course transcriptome analysis of rice (Oryza sativa) leaves in natural field conditions revealed that OsGIGANTEA, the sole rice ortholog of the Arabidopsis GIGANTEA gene, governs the robust diurnal rhythm of rice leaf transcriptomes even under natural diurnal conditions; rice Osgi mutants exhibited severely defective transcriptome rhythms under strong diurnal changes in environmental cues. This review focuses on the physiological significance of the plant circadian clock in natural field conditions. © 2012 Blackwell Publishing Ltd.

Kobayashi T.,Japan National Institute of Agrobiological Science
Journal of Insect Physiology | Year: 2016

Many plant-parasite interactions that include major plant resistance genes have subsequently been shown to exhibit features of gene-for-gene interactions between plant Resistance genes and parasite Avirulence genes. The brown planthopper (BPH) Nilaparvata lugens is an important pest of rice (Oryza sativa). Historically, major Resistance genes have played an important role in agriculture. As is common in gene-for-gene interactions, evolution of BPH virulence compromises the effectiveness of singly-deployed resistance genes. It is therefore surprising that laboratory studies of BPH have supported the conclusion that virulence is conferred by changes in many genes rather than a change in a single gene, as is proposed by the gene-for-gene model. Here we review the behaviour, physiology and genetics of the BPH in the context of host plant resistance. A problem for genetic understanding has been the use of various insect populations that differ in frequencies of virulent genotypes. We show that the previously proposed polygenic inheritance of BPH virulence can be explained by the heterogeneity of parental populations. Genetic mapping of Avirulence genes indicates that virulence is a monogenic trait. These evolving concepts, which have brought the gene-for-gene model back into the picture, are accelerating our understanding of rice-BPH interactions at the molecular level. © 2015 Elsevier Ltd.

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