Koji Yano

Publications of Koji Yano

• Host plant genome overcomes the lack of a bacterial gene for symbiotic nitrogen fixation.

  Authors: Tsuneo Hakoyama, Kaori Niimi, Hirokazu Watanabe, Ryohei Tabata, Junichi Matsubara, Shusei Sato, Yasukazu Nakamura, Satoshi Tabata, Li Jichun, Tsuyoshi Matsumoto, Kazuyuki Tatsumi, Mika Nomura, Shigeyuki Tajima, Masumi Ishizaka, Koji Yano, Haruko Imaizumi-Anraku, Masayoshi Kawaguchi, Hiroshi Kouchi, Norio Suganuma

  Nature. 11/2009; 462(7272):514-7.

  Homocitrate is a component of the iron-molybdenum cofactor in nitrogenase, where nitrogen fixation occurs. NifV, which encodes homocitrate synthase (HCS), has been identified from various diazotrophsHomocitrate is a component of the iron-molybdenum cofactor in nitrogenase, where nitrogen fixation occurs. NifV, which encodes homocitrate synthase (HCS), has been identified from various diazotrophs but is not present in most rhizobial species that perform efficient nitrogen fixation only in symbiotic association with legumes. Here we show that the FEN1 gene of a model legume, Lotus japonicus, overcomes the lack of NifV in rhizobia for symbiotic nitrogen fixation. A Fix(-) (non-fixing) plant mutant, fen1, forms morphologically normal but ineffective nodules. The causal gene, FEN1, was shown to encode HCS by its ability to complement a HCS-defective mutant of Saccharomyces cerevisiae. Homocitrate was present abundantly in wild-type nodules but was absent from ineffective fen1 nodules. Inoculation with Mesorhizobium loti carrying FEN1 or Azotobacter vinelandii NifV rescued the defect in nitrogen-fixing activity of the fen1 nodules. Exogenous supply of homocitrate also recovered the nitrogen-fixing activity of the fen1 nodules through de novo nitrogenase synthesis in the rhizobial bacteroids. These results indicate that homocitrate derived from the host plant cells is essential for the efficient and continuing synthesis of the nitrogenase system in endosymbionts, and thus provide a molecular basis for the complementary and indispensable partnership between legumes and rhizobia in symbiotic nitrogen fixation.

• CERBERUS, a novel U-box protein containing WD-40 repeats is required for infection thread formation and nodule development in the legume-Rhizobium symbiosis.

  Authors: Koji Yano, Satoshi Shibata, Wen-Li Chen, Shusei Sato, Takakazu Kaneko, Anna Jurkiewicz, Niels Sandal, Mari Banba, Haruko Imaizumi-Anraku, Tomoko Kojima, Ryo Ohtomo, Krzysztof Szczyglowski, Jens Stougaard, Satoshi Tabata, Makoto Hayashi, Hiroshi Kouchi, Yosuke Umehara

  The Plant journal : for cell and molecular biology. 07/2009;

  Endosymbiotic infection of legume plants by Rhizobium bacteria is initiated through infection threads (ITs) which are initiated within and penetrate from root hairs and deliver the endosymbionts intoEndosymbiotic infection of legume plants by Rhizobium bacteria is initiated through infection threads (ITs) which are initiated within and penetrate from root hairs and deliver the endosymbionts into nodule cells. Despite recent progress in understanding the mutual recognition and early symbiotic signaling cascades in host legumes, the molecular mechanisms underlying bacterial infection processes and successive nodule organogenesis are still poorly understood. We isolated a novel symbiotic mutant of Lotus japonicus, cerberus, which shows defects in IT formation and nodule organogenesis. Map-based cloning of the causal gene allowed us to identify the CERBERUS gene, which encodes a novel protein containing a U-box domain and WD-40 repeats. CERBERUS expression was detected in the roots and nodules, and enhanced after inoculation of Mesorhizobium loti. Strong expression was detected in developing nodule primordia and the infected zone of mature nodules. In cerberus mutants, Rhizobium colonized curled root hair tips, but hardly penetrated into root hair cells. The occasional ITs that were formed inside the root hair cells were mostly arrested within the epidermal cell layer. Nodule organogenesis was aborted prematurely, resulting in formation of a large number of small bumps which contained no endosymbiotic bacteria. These phenotypic and genetic analyses, together with comparisons to other legume mutants with defects in IT formation, indicate that CERBERUS plays a critical role in the very early steps of IT formation as well as for growth and differentiation of nodules.

• CYCLOPS, a mediator of symbiotic intracellular accommodation.

  Authors: Koji Yano, Satoko Yoshida, Judith Müller, Sylvia Singh, Mari Banba, Kate Vickers, Katharina Markmann, Catharine White, Bettina Schuller, Shusei Sato, Erika Asamizu, Satoshi Tabata, Yoshikatsu Murooka, Jillian Perry, Trevor L Wang, Masayoshi Kawaguchi, Haruko Imaizumi-Anraku, Makoto Hayashi, Martin Parniske

  Proceedings of the National Academy of Sciences of the United States of America. 01/2009;

  The initiation of intracellular infection of legume roots by symbiotic rhizobia bacteria and arbuscular mycorrhiza (AM) fungi is preceded by the induction of calcium signatures in and around theThe initiation of intracellular infection of legume roots by symbiotic rhizobia bacteria and arbuscular mycorrhiza (AM) fungi is preceded by the induction of calcium signatures in and around the nucleus of root epidermal cells. Although a calcium and calmodulin-dependent kinase (CCaMK) is a key mediator of symbiotic root responses, the decoding of the calcium signal and the molecular events downstream are only poorly understood. Here, we characterize Lotus japonicus cyclops mutants on which microbial infection was severely inhibited. In contrast, nodule organogenesis was initiated in response to rhizobia, but arrested prematurely. This arrest was overcome when a deregulated CCaMK mutant version was introduced into cyclops mutants, conferring the development of full-sized, spontaneous nodules. Because cyclops mutants block symbiotic infection but are competent for nodule development, they reveal a bifurcation of signal transduction downstream of CCaMK. We identified CYCLOPS by positional cloning. CYCLOPS carries a functional nuclear localization signal and a predicted coiled-coil domain. We observed colocalization and physical interaction between CCaMK and CYCLOPS in plant and yeast cell nuclei in the absence of symbiotic stimulation. Importantly, CYCLOPS is a phosphorylation substrate of CCaMK in vitro. Cyclops mutants of rice were impaired in AM, and rice CYCLOPS could restore symbiosis in Lotus cyclops mutants, indicating a functional conservation across angiosperms. Our results suggest that CYCLOPS forms an ancient, preassembled signal transduction complex with CCaMK that is specifically required for infection, whereas organogenesis likely requires additional yet-to-be identified CCaMK interactors or substrates.

• NUCLEOPORIN85 is required for calcium spiking, fungal and bacterial symbioses, and seed production in Lotus japonicus.

  Authors: Katsuharu Saito, Makoto Yoshikawa, Koji Yano, Hiroki Miwa, Hisaki Uchida, Erika Asamizu, Shusei Sato, Satoshi Tabata, Haruko Imaizumi-Anraku, Yosuke Umehara, Hiroshi Kouchi, Yoshikatsu Murooka, Krzysztof Szczyglowski, J Allan Downie, Martin Parniske, Makoto Hayashi, Masayoshi Kawaguchi

  The Plant cell. 03/2007; 19(2):610-24.

  In Lotus japonicus, seven genetic loci have been identified thus far as components of a common symbiosis (Sym) pathway shared by rhizobia and arbuscular mycorrhizal fungi. We characterized the nup85In Lotus japonicus, seven genetic loci have been identified thus far as components of a common symbiosis (Sym) pathway shared by rhizobia and arbuscular mycorrhizal fungi. We characterized the nup85 mutants (nup85-1, -2, and -3) required for both symbioses and cloned the corresponding gene. When inoculated with Glomus intraradices, the hyphae managed to enter between epidermal cells, but they were unable to penetrate the cortical cell layer. The nup85-2 mutation conferred a weak and temperature-sensitive symbiotic phenotype, which resulted in low arbuscule formation at 22 degrees C but allowed significantly higher arbuscule formation in plant cortical cells at 18 degrees C. On the other hand, the nup85 mutants either did not form nodules or formed few nodules. When treated with Nod factor of Mesorhizobium loti, nup85 roots showed a high degree of root hair branching but failed to induce calcium spiking. In seedlings grown under uninoculated conditions supplied with nitrate, nup85 did not arrest plant growth but significantly reduced seed production. NUP85 encodes a putative nucleoporin with extensive similarity to vertebrate NUP85. Together with symbiotic nucleoporin NUP133, L. japonicus NUP85 might be part of a specific nuclear pore subcomplex that is crucial for fungal and rhizobial colonization and seed production.

• Identification of symbiotically defective mutants of Lotus japonicus affected in infection thread growth.

  Authors: Fabien Lombardo, Anne B Heckmann, Hiroki Miwa, Jillian A Perry, Koji Yano, Makoto Hayashi, Martin Parniske, Trevor L Wang, J Allan Downie

  Molecular plant-microbe interactions : MPMI. 01/2007; 19(12):1444-50.

  During the symbiotic interaction between legumes and rhizobia, the host cell plasma membrane and associated plant cell wall invaginate to form a tunnel-like infection thread, a structure in whichDuring the symbiotic interaction between legumes and rhizobia, the host cell plasma membrane and associated plant cell wall invaginate to form a tunnel-like infection thread, a structure in which bacteria divide to reach the plant root cortex. We isolated four Lotus japonicus mutants that make infection pockets in root hairs but form very few infection threads after inoculation with Mesorhizobium loti. The few infection threads that did initiate in the mutants usually did not progress further than the root hair cell. These infection-thread deficient (itd) mutants were unaffected for early symbiotic responses such as calcium spiking, root hair deformation, and curling, as well as for the induction of cortical cell division and the arbuscular mycorrhizal symbiosis. Complementation tests and genetic mapping indicate that itd2 is allelic to Ljsym7, whereas the itdl, itd3, and itd4 mutations identified novel loci. Bacterial release into host cells did occur occasionally in the itdl, itd2, and itd3 mutants suggesting that some infections may succeed after a long period and that infection of nodule cells could occur normally if the few abnormal infection threads that were formed reached the appropriate nodule cells.

• New nodulation mutants responsible for infection thread development in Lotus japonicus.

  Authors: Koji Yano, Myra L Tansengco, Taihei Hio, Kuniko Higashi, Yoshikatsu Murooka, Haruko Imaizumi-Anraku, Masayoshi Kawaguchi, Makoto Hayashi

  Molecular plant-microbe interactions : MPMI. 08/2006; 19(7):801-10.

  Legume plants develop specialized root organs, the nodules, through a symbiotic interaction with rhizobia. The developmental process of nodulation is triggered by the bacterial microsymbiont butLegume plants develop specialized root organs, the nodules, through a symbiotic interaction with rhizobia. The developmental process of nodulation is triggered by the bacterial microsymbiont but regulated systemically by the host legume plants. Using ethylmethane sulfonate mutagenesis as a tool to identify plant genes involved in symbiotic nodule development, we have isolated and analyzed five nodulation mutants, Ljsym74-3, Ljsym79-2, Ljsym79-3, Ljsym80, and Ljsym82, from the model legume Lotus japonicus. These mutants are defective in developing functional nodules and exhibit nitrogen starvation symptoms after inoculation with Mesorhizobium loti. Detailed observation revealed that infection thread development was aborted in these mutants and the nodules formed were devoid of infected cells. Mapping and complementation tests showed that Ljsym74-3, and Ljsym79-2 and Ljsym79-3, were allelic with reported mutants of L. japonicus, alb1 and crinkle, respectively. The Ljsym82 mutant is unique among the mutants because the infection thread was aborted early in its development. Ljsym74-3 and Ljsym80 were characterized as mutants with thick infection threads in short root hairs. Map-based cloning and molecular characterization of these genes will help us understand the genetic mechanism of infection thread development in L. japonicus.

• Genetics of symbiosis in Lotus japonicus: recombinant inbred lines, comparative genetic maps, and map position of 35 symbiotic loci.

  Authors: Niels Sandal, Thomas Rørby Petersen, Jeremy Murray, Yosuke Umehara, Bogumil Karas, Koji Yano, Hirotaka Kumagai, Makoto Yoshikawa, Katsuharu Saito, Masaki Hayashi [......] Shingo Hata, Norio Suganuma, Hiroshi Kouchi, Shinji Kawasaki, Satoshi Tabata, Makoto Hayashi, Martin Parniske, Krzysztof Szczyglowski, Masayoshi Kawaguchi, Jens Stougaard

  Molecular plant-microbe interactions : MPMI. 02/2006; 19(1):80-91.

  Development of molecular tools for the analysis of the plant genetic contribution to rhizobial and mycorrhizal symbiosis has provided major advances in our understanding of plant-microbeDevelopment of molecular tools for the analysis of the plant genetic contribution to rhizobial and mycorrhizal symbiosis has provided major advances in our understanding of plant-microbe interactions, and several key symbiotic genes have been identified and characterized. In order to increase the efficiency of genetic analysis in the model legume Lotus japonicus, we present here a selection of improved genetic tools. The two genetic linkage maps previously developed from an interspecific cross between L. japonicus Gifu and L. filicaulis, and an intraspecific cross between the two ecotypes L. japonicus Gifu and L. japonicus MG-20, were aligned through a set of anchor markers. Regions of linkage groups, where genetic resolution is obtained preferentially using one or the other parental combination, are highlighted. Additional genetic resolution and stabilized mapping populations were obtained in recombinant inbred lines derived by a single seed descent from the two populations. For faster mapping of new loci, a selection of reliable markers spread over the chromosome arms provides a common framework for more efficient identification of new alleles and new symbiotic loci among uncharacterized mutant lines. Combining resources from the Lotus community, map positions of a large collection of symbiotic loci are provided together with alleles and closely linked molecular markers. Altogether, this establishes a common genetic resource for Lotus spp. A web-based version will enable this resource to be curated and updated regularly.

• Characterization of the Lotus japonicus symbiotic mutant lot1 that shows a reduced nodule number and distorted trichomes.

  Authors: Yasuhiro Ooki, Mari Banba, Koji Yano, Jumpei Maruya, Shusei Sato, Satoshi Tabata, Kazuhiko Saeki, Makoto Hayashi, Masayoshi Kawaguchi, Katsura Izui, Shingo Hata

  Plant physiology. 05/2005; 137(4):1261-71.

  We isolated a recessive symbiotic mutant of Lotus japonicus that defines a genetic locus, LOT1 (for low nodulation and trichome distortion). The nodule number per plant of the mutant was aboutWe isolated a recessive symbiotic mutant of Lotus japonicus that defines a genetic locus, LOT1 (for low nodulation and trichome distortion). The nodule number per plant of the mutant was about one-fifth of that of the wild type. The lot1 mutant showed a moderate dwarf phenotype and distorted trichomes, but its root hairs showed no apparent differences to those of the wild type. Infection thread formation after inoculation of Mesorhizobium loti was repressed in lot1 compared to that in the wild type. The nodule primordia of lot1 did not result in any aborted nodule-like structure, all nodules becoming mature and exhibiting high nitrogen fixation activity. The mutant was normally colonized by mycorrhizal fungi. lot1 also showed higher sensitivity to nitrate than the wild type. The grown-up seedlings of lot1 were insensitive to any ethylene treatments with regard to nodulation, although the mutant showed normal triple response on germination. It is conceivable that a nodulation-specific ethylene signaling pathway is constitutively activated in the mutant. Grafting experiments with lot1 and wild-type seedlings suggested that the root genotype mainly determines the low nodulation phenotype of the mutant, while the trichome distortion is regulated by the shoot genotype. Grafting of har1-4 shoots to lot1 roots resulted in an intermediate nodule number, i.e. more than that of lot1 and less than that of har1-4. Putative double mutants of lot1 and har1 also showed intermediate nodulation. Thus, it was indicated that LOT1 is involved in a distinct signal transduction pathway independent of HAR1.

• Lotus burttii takes a position of the third corner in the lotus molecular genetics triangle.

  Authors: Masayoshi Kawaguchi, Andrea Pedrosa-Harand, Koji Yano, Makoto Hayashi, Yoshikatsu Murooka, Katsuharu Saito, Toshiyuki Nagata, Kiyoshi Namai, Hiroshi Nishida, Daisuke Shibata, Shusei Sato, Satoshi Tabata, Masaki Hayashi, Kyuya Harada, Niels Sandal, Jens Stougaard, Andreas Bachmair, William F Grant

  DNA research : an international journal for rapid publication of reports on genes and genomes. 03/2005; 12(1):69-77.

  In order to consolidate molecular genetic system in Lotus japonicus and to further access the biological diversity in Lotea, we introduce here Lotus burttii B-303 derived from West Pakistan as theIn order to consolidate molecular genetic system in Lotus japonicus and to further access the biological diversity in Lotea, we introduce here Lotus burttii B-303 derived from West Pakistan as the third crossing partner of the Gifu ecotype (B-129-S9) for a genetic analysis. L. burttii is a relatively small and early flowering plant with non-shattering behavior. The general chromosome morphology is very similar to Gifu, and fluorescence in situ hybridization (FISH) analysis revealed that the short arm of chromosome 1 in L. burttii is comparable to that of Gifu, indicating that the translocation event involving chromosomes 1 and 2, which was observed in L. japonicus Miyakojima MG-20, is not present in L. burttii. In addition L. burttii has a higher level of DNA polymorphism compared to Gifu and MG-20 enabling design of codominant markers such as SSR, CAPS and dCAPS. Using an F2 population from a cross between Gifu and L. burttii, codominant makers that co-segregated at the translocation site could be expanded. In order to normalize the genetic background, L. burttii was inbred for nine generations and the germplasm L. burttii B-303-S9 was established.