Shizen Ohnishi

Publications (9) View all

• Article: Multigenic system controlling viral systemic infection determined by the interactions between Cucumber mosaic virus genes and quantitative trait loci of soybean cultivars.

  Shizen Ohnishi, Issei Echizenya, Eri Yoshimoto, Kim Boumin, Tsuyoshi Inukai, Chikara Masuta
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  ABSTRACT: Soybean 'Harosoy' is resistant to Cucumber mosaic virus soybean strain C (CMV-SC) and susceptible to CMV-S strain D (CMV-SD). Using enzyme-linked immunosorbent assay and Northern hybridization, we characterized the Harosoy resistance and found that CMV-SC did not spread systemically but was restricted to the inoculated leaves in Harosoy. Harosoy resistance was not controlled by either a dominant or recessive single gene. To dissect this system controlling long-distance movement of CMV in soybean, we constructed infectious cDNA clones of CMV-SC and CMV-SD. Using these constructs and the chimeric RNAs, we demonstrated that two viral components were required for systemic infection by the virus. The region including the entire 2b gene and the 5' region of RNA3 (mainly the 5' untranslated region) together were required. By quantitative trait locus (QTL) analysis using an F(2) population and the F(3) families derived from Harosoy and susceptible 'Nemashirazu', we also showed that at least three QTLs affected systemic infection of CMV in soybean. Our study on Harosoy resistance to CMV-SC revealed an interesting mechanism, in which multiple host and viral genes coordinately controlled viral systemic infection.
  Phytopathology 05/2011; 101(5):575-82. · 2.80 Impact Factor
• Article: Variation of GmIRCHS (Glycine max inverted-repeat CHS pseudogene) is related to tolerance of low temperature-induced seed coat discoloration in yellow soybean.

  Shizen Ohnishi, Hideyuki Funatsuki, Atsushi Kasai, Tasuku Kurauchi, Naoya Yamaguchi, Toru Takeuchi, Hiroyuki Yamazaki, Hideki Kurosaki, Shigehisa Shirai, Tomoaki Miyoshi, Harukuni Horita, Mineo Senda
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  ABSTRACT: In yellow soybean, seed coat pigmentation is inhibited by post-transcriptional gene silencing (PTGS) of chalcone synthase (CHS) genes. A CHS cluster named GmIRCHS (Glycine max inverted-repeat CHS pseudogene) is suggested to cause PTGS in yellow-hilum cultivars. Cold-induced seed coat discoloration (CD), a commercially serious deterioration of seed appearance, is caused by an inhibition of this PTGS upon exposure to low temperatures. In the highly CD-tolerant cultivar Toyoharuka, the GmIRCHS structure differs from that of other cultivars. The aim of this study was to determine whether the variation of GmIRCHS structure among cultivars is related to variations in CD tolerance. Using two sets of recombinant inbred lines between Toyoharuka and CD-susceptible cultivars, we compared the GmIRCHS genotype and CD tolerance phenotype during low temperature treatment. The GmIRCHS genotype was related to the phenotype of CD tolerance. A QTL analysis around GmIRCHS showed that GmIRCHS itself or a region located very close to it was responsible for CD tolerance. The variation in GmIRCHS can serve as a useful DNA marker for marker-assisted selection for breeding CD tolerance. In addition, QTL analysis of the whole genome revealed a minor QTL that also affected CD tolerance.
  Theoretical and Applied Genetics 10/2010; 122(3):633-42. · 3.30 Impact Factor
• Article: Molecular mechanism of seed coat discoloration induced by low temperature in yellow soybean.

  Atsushi Kasai, Shizen Ohnishi, Hiroyuki Yamazaki, Hideyuki Funatsuki, Tasuku Kurauchi, Takuro Matsumoto, Setsuzo Yumoto, Mineo Senda
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  ABSTRACT: Seed coat pigmentation is inhibited in yellow soybean. The I gene inhibits pigmentation over the entire seed coat. In yellow soybean, seed coat discoloration occurs when plants are exposed to low temperatures after the onset of flowering, a phenomenon named 'cold-induced discoloration (CD)'. Inhibition of seed coat pigmentation results from post-transcriptional gene silencing (PTGS) of the chalcone synthase (CHS) genes. PTGS is a sequence-specific RNA degradation mechanism in plants and occurs via short interfering RNAs (siRNAs). Similar post-transcriptional suppression is called RNAi (RNA interference) in animals. Recently, we identified a candidate of the I gene designated GmIRCHS. In this study, to elucidate the molecular mechanism of CD, CHS mRNA and siRNA levels in the seed coat were compared between CD-sensitive and CD-tolerant cultivars (Toyomusume and Toyoharuka, respectively). In Toyomusume, the CHS siRNA level was reduced markedly by low temperature treatment, and subsequently the CHS mRNA level increased rapidly after treatment. In contrast, low temperature treatment did not result in severe reduction of the CHS siRNA level in Toyoharuka, and the CHS mRNA level did not increase after the treatment. These results suggest that the rapid increase in CHS mRNA level after low temperature treatment may lead to enhanced pigmentation in some of the seed coat cells and finally in seed coat discoloration. Interestingly, we found a Toyoharuka-specific difference in the GmIRCHS region, which may be involved in CD tolerance.
  Plant and Cell Physiology 05/2009; 50(6):1090-8. · 4.70 Impact Factor
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  Available from: iastate.edu

  Article: Infection of soybean by cucumber mosaic virus as determined by viral movement protein.

  J S Hong, S Ohnishi, C Masuta, J K Choi, K H Ryu
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  ABSTRACT: To characterize the host range determinant of the soybean strain of Cucumber mosaic virus (CMV) we analyzed a series of pseudorecombinants and chimeric viruses between infectious transcripts from two soybean strains (CMV-SC and CMV-SD) and an ordinary strain (CMV-Y). CMV-Y could not infect soybeans, even locally. Systemic infection of the two soybean-adapted soybean isolates on soybean plants mapped to RNA3. Chimeric RNA3s from between CMV-SC and CMV-Y, and chimeric RNA3s from between CMV-SC and CMV-SD, were made and inoculated onto wild soybean Iwate and soybean cv. Tsurunoko. The 3a region determined the viral systemic movement in the plants. In the wild soybean ecotype Hyougo, cell-to-cell movement of two different CMV soybean strains, one of which infects systemically while the other does not, in the inoculated leaves were almost the same, suggesting that the resistance of soybean operates at the level of long-distance movement. Our results clearly suggest that movement protein is a host determinant of CMV soybean strains.
  Archives of Virology 03/2007; 152(2):321-8. · 2.11 Impact Factor
• Article: Fine mapping of foxglove aphid (Aulacorthum solani) resistance gene Raso1 in soybean and its effect on tolerance to Soybean dwarf virus transmitted by foxglove aphid.

  Shizen Ohnishi, Noriyuki Miyake, Toru Takeuchi, Fumiko Kousaka, Satoshi Hiura, Osamu Kanehira, Miki Saito, Takashi Sayama, Ayako Higashi, Masao Ishimoto, Yoshinori Tanaka, Shohei Fujita
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  ABSTRACT: Soybean dwarf virus (SbDV) causes serious dwarfing, yellowing and sterility in soybean (Glycine max). The soybean cv. Adams is tolerant to SbDV infection in the field and exhibits antibiosis to foxglove aphid (Aulacorthum solani), which transmits SbDV. This antibiosis (termed "aphid resistance") is required for tolerance to SbDV in the field in segregated progenies of Adams. A major quantitative trait locus, Raso1, is reported for foxglove aphid resistance. Our objectives were to fine map Raso1 and to reveal whether Raso1 alone is sufficient to confer both aphid resistance and SbDV tolerance. We introduced Raso1 into cv. Toyomusume by backcrossing and investigated the degree of aphid antibiosis to foxglove aphid and the degree of tolerance to SbDV in the field. All Raso1-introduced backcross lines showed aphid resistance. Interestingly, only one Raso1-introduced backcross line (TM-1386) showed tolerance to SbDV in the field. The results demonstrated Raso1 alone is sufficient to confer aphid resistance but insufficient for SbDV tolerance. Tolerance to SbDV was indicated to require additional gene(s) to Raso1. Additionally, Raso1 was mapped to a 63-kb interval on chromosome 3 of the Williams 82 sequence assembly (Glyma1). This interval includes a nucleotide-binding site-leucine-rich repeat encoding gene and two other genes in the Williams 82 soybean genome sequence.
  Breeding Science 01/2012; 61(5):618-24. · 1.25 Impact Factor