Papers - ISHIGAKI Genki
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Prasojo Y., Ishigaki G., Fukuyama K., Akashi R.
IOP Conference Series: Earth and Environmental Science 387 ( 1 ) 2019.12
Language：English Publishing type：Research paper (scientific journal) Publisher：IOP Conference Series: Earth and Environmental Science
© Published under licence by IOP Publishing Ltd. Tropical grasses mainly utilized in southwestern Japan exhibited that the dry matter yield is increased as the growth stage. However, the nutritive value, such as crude protein (CP) and non-fibrous carbohydrate (NFC) decreased strikingly. Therefore, breeding for the new grass or crops with high potential as protein source is an urgent problem. The aim of the study were to investigate the dry matter yield of two soybean cultivars ('Miyakonojo' and 'Williams82') with Rhodes grass as living mulch plant after 1st cutting and to investigate the nutritive value of the silage. The growth of the Rhodes grass hampered the growth of soybean at the initial and the subsequent growth stages. Hence, the dry matter yield of soybean ranged from 9.8 kg/10a to 26.6 kg/10a, correspond to about 3 to 10% of total dry matter yield. The nutritive value of EE, CA and CP in Rhodes grass with soybean silage higher than those of Rhodes grass silage. These results suggest that the addition of soybean biomass could be useful for increasing the nutrition value of silage. Moreover, it is necessary to choose an appropriate sowing date to increase dry matter yield of soybean biomass in southwestern of Japan.
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Nitthaisong P., Ishigaki G., Suenaga K., Muguerza M., Tanaka H., Akashi R.
Crop Science 59 ( 4 ) 1648 - 1656 2019.7
Language：English Publishing type：Research paper (scientific journal) Publisher：Crop Science
© 2019 The Author(s). Urochloa species are a rich source of quality forage in the tropical and subtropical areas, and cultivated species are predominantly facultative apomictic. They are well adapted to poor soil conditions, resistant to heavy grazing, and drought tolerant, but some Urochloa species produce poor pasture and seed yield. Therefore, it is important to complement and to combine characteristics of different species in breeding programs. We have conducted interspecific crosses between diploid U. ruziziensis (R. Germ. & C. M. Evrard) Crins ‘Kennedy’ (2n = 2x = 18) with apomictic tetraploids U. decumbens (Stapf) R. D. Webster ‘Basilisk’ (2n = 4x = 36) and U. brizantha (Hochst. ex A. Rich.) R. D. Webster ‘Marandu’ (2n = 4x = 36). Diploid, triploid, and tetraploid plants were obtained from these crosses. The triploid plants were further crossed with ‘Basilisk’ to produce a BC1F1 generation. Although no seeds were produced by self-pollination of the F1 triploid hybrids, backcrossing eventually produced triploid, tetraploid, and pentaploid plants (BC1F1). Only the pentaploid plants produced seeds by self-pollination. This is the first report of the production of apomictic pentaploid progenies from interspecific crosses in Urochloa.
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Evaluation of Drying Characteristics of Rhodesgrass (Chloris gayana) and New Tetraploid Ruzigrass (Urochloa ruziziensis) Reviewed
Genki Ishigaki, Yogi Sidik Prasojo, Pattama Nitthaisong, Kiichi Fukuyama, Ryo Akashi
日本暖地畜産学会報 62 ( 1 ) 25 - 30 2019.3
Language：Japanese Publishing type：Research paper (scientific journal)
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Ishigaki G., Nitthaisong P., Prasojo Y., Kobayashi I., Fukuyama K., Rahman M., Akashi R.
Asian-Australasian Journal of Animal Sciences 31 ( 5 ) 748 - 754 2018.5
Language：English Publishing type：Research paper (scientific journal) Publisher：Asian-Australasian Journal of Animal Sciences
Copyright © 2018 by Asian-Australasian Journal of Animal Sciences. Objective: The preference evaluation of cattle is an important factor for estimation and improvement of the grazing amounts of newly introduced or bred grasses or cultivars in barn. This study was performed to assess the grazing behavior (the amount of grazing and/or the grazing speed) of cattle as indirect method using newly bred Brachiaria ruziziensis tetraploid strain ‘OKI1’(BR) hay as treatment group and Cloris gayana ‘Callide’ (CG) hay as control group. It also compared the feasibility of using behavioral differences between two groups as one criteria for evaluating preference by Japanese black cattle in barn. Methods: Three experiments were carried out using 12 growing Japanese Black cattle including 6 males and 6 females. In each experiment, the four Japanese Black cattle (2 males and 2 females) were placed in separated stall and allowed to graze BR and CG in manger that was separated into two portions for about 30 min. The position and behavior of the cattle were recorded, and weighed the residual of each gay at 15 and 30 minutes after experiment start. Results: The BR was superior to CG in chemical composition such as protein, fibers and nonfibrous carbohydrate. The cattle, over all, tended to prefer BR over CG in the first half 15 minutes in terms of the time spent and amount of grazing. Additionally, growing cattle exhibited neophilia for BR bred newly. Conclusion: These findings indicated the current approach could be applied for one of criteria to evaluate the preference of hay by Japanese black cattle under indoor housing environment.
DOI： 10.5713/ajas.17.0543
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Wee C., Hashiguchi M., Ishigaki G., Muguerza M., Oba C., Abe J., Harada K., Akashi R.
Plant Genetic Resources: Characterisation and Utilisation 16 ( 2 ) 94 - 102 2018.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Plant Genetic Resources: Characterisation and Utilisation
© NIAB 2017. Seed composition, including the protein, lipid and sucrose contents of 334 accessions of wild soybean(Glycine soja) collected in Japan, was evaluated using near-infrared reflectance spectroscopy(NIRS) technology. The distribution of protein, lipid and sucrose contents and correlations amongthese three classes of seed components were determined. Protein, lipid and sucrose levels ranged inaccessions from 48.6 to 57.0, 9.0 to 14.3 and 1.24 to 3.53%, respectively. Average levels of protein,lipid and sucrose in the accessions were 54, 11 and 2.5%, respectively. High negative correlationswere observed between the protein and lipid contents, and the protein and sucrose contents. Meanlevels of the three constituents were compared among collection sites classified by climatic conditions.The total protein content of accessions from regions with a high annual mean temperature washigh. The protein content of accessions from the II-1 region was higher than those from the III-3region, and the sucrose content from the II-1 region was lower than those from regions III-2 andIV-3. The lipid content of plants from the II-1 region was lower than those from other regions,and the accessions in region II had a higher protein content and lower sucrose and lipid contentsthan the other regions. These results provide diverse and wide-ranged protein, lipid and sucrosecontents information of Japanese wild soybean resources according to climatic region; thus, providinga foundation for the future development and selection of new soybean varieties with desiredtraits in global environmental changes.
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Grazing potential of foggage and fresh dwarf Napiergrass pasture by breeding beef cows in southern Kyushu, Japan.
Kadwal MH, Ishii Y, Goto A, Li BK, Idota S, Niimi M, Ishigaki G, Fukuyama K
Wulfenia Journal 24 140 - 157 2018.1
Language：Japanese Publishing type：Research paper (scientific journal)
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Compaction Resistance of some species in Tropical grasses Reviewed
ISHIGAKI Genki, NITTHAISONG Pattama, AKASHI Ryo, FUKUYAMA Kiichi
Nihon Danchi Chikusan Gakkaihou 61 ( 1 ) 27 - 32 2018
Authorship：Lead author Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Warm Regional Society of Animal Science, Japan
Heavy field equipment contributes to plant compaction and soil compaction. These phenomena impede many physiological deteriorations in tiller generation, leaf elongation and root activities and cause stunting and yield loss in grasses. We conducted a comparative study between two <i>Brachiaria</i> grasses (<i>B. ruziziensis</i> and <i>B. brizantha</i>) and rhodes grass (<i>Chloris gayana</i>). Compact pressure was conducted by one side wheel of agricultural machinery (gross weight: 2.7 t) for three times. The tolerance capacity of the three tropical grasses was investigated in terms of plant length, stem diameter, leaf emergence speed, the transition of the number of tillers and dry matter yield. For plant length and stem diameter, a significant difference (<i>P</i> < 0.05) was recognized between compaction treatment and non-compaction treatment in rhodes grass. The leaf emergence speed was decreased under compaction treatment in palisade grass significantly (<i>P</i> < 0.05). For the number of tiller regenerated, rhodes grass showed the highest value among grasses. On the other hand, ruzi grass and palisade grass exhibited the vigorous generation of new tillers after first cutting regardless of compaction treatment. The amount of second dry matter yield of three grasses were ordered as follows: palisade grass > ruzi grass > rhodes grass although the differences were not significant. In conclusion, these tropical grasses varied the responses against the compact pressure because of the differences of plant part influenced and the degree, and the different approach for the maintenance the number of tillers. Additionally, ruzi grass and palisade grass were more superior than rhodes grass, indicating that these new introduced forage grasses can be useful as an annual forage production under agricultural machinery system.
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Asanuma Y, Gondo T, Ishigaki G, Inoue K, Zaita N, Muguerza M, Akashi R
GM Crops and Food 8 ( 2 ) 106 - 116 2017.4
Language：English Publishing type：Research paper (scientific journal) Publisher：GM Crops and Food
© 2017 Taylor & Francis. Japan imports cottonseed mainly from Australia and the USA where more than 96% of all cotton varieties grown are genetically modified (GM). GM crops undergo an environmental risk assessment (ERA) under the Law Concerning the Conservation and Sustainable Use of Biological Diversity before import into Japan. Potential adverse effects on biodiversity are comprehensively assessed based on competitiveness, production of harmful substances and outcrossing ability. Even though imported cottonseed is intended for food and feed uses and not for cultivation, the potential risks from seed spillage during transport must be evaluated. In most cases, the ERA requires data collected from in-country field trials to demonstrate how the GM crop behaves in Japan's environment. Confined field trials in Japan were conducted for the ERA of Lepidoptera-resistant and glufosinate-tolerant GM cotton (Gossypium hirsutum L.) lines GHB119 and T304-40. These lines were compared with conventional varieties for growth habit, morphological characteristics, seed dormancy, and allelopathic activity associated with competitiveness and production of harmful substances. Outcrossing ability was not a concern due to the absence of sexually compatible wild relatives in Japan. Although slight statistical differences were observed between the GM line and its conventional comparator for some morphological characteristics, transgenes or transformation were not considered to be responsible for these differences. The trial demonstrated that competitiveness and production of harmful substances by these GM cotton lines were equivalent to conventional cotton varieties that have a long history of safe use, and no potential adverse effects to biosafety in Japan were observed.
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Nitthaisong P., Ishigaki G., Fukuyama K., Akashi R.
Grassland Science 63 ( 2 ) 79 - 84 2017.4
Language：English Publishing type：Research paper (scientific journal) Publisher：Grassland Science
© 2017 Japanese Society of Grassland Science Tropical grasses with high forage quality and biomass could be grown as annuals in warm subtropical regions as an additional source of feedstock. For sustainable forage production, it is also vital to know the interactions between plant and weed for the selection of promising alternating forage grass. Brachiaria grass has been used as source of high quality forage in the tropics, and this could be developed as a promising forage grass species in this region. Therefore, this study compared the agronomic traits, productivity, and dominance to weeds in six Brachiaria cultivars with two rhodesgrass cultivars in southwestern Kyushu, Japan. This study was evaluated twice from spring to autumn in 2012. Most Brachiaria cultivars grew more vigorously than the two rhodesgrass cultivars during early seedling development in 2012. Except for ‘Llanero’, all Brachiaria cultivars had a higher dry matter yield than the two rhodesgrass cultivars. Notably, ‘Kennedy’ had the highest dry matter yield of 9.5 t ha−1 at the second cutting, resulting from substantial regrowth after the first cutting. However, two Brachiaria cultivars and one rhodesgrass cultivar evaluated in 2014 were not significantly different. Except ‘Llanero’, biomass percentage in all Brachiaria cultivars ranged from 57 to 81% at the first cutting. Subsequently, the value for the second cutting increased more than 90%. There was a significant positive correlation (P < 0.01) between dominance to weeds and growth in the early stage, indicating that the vigorous growth of Brachiaria grasses, during the early stage was superior to that of weeds in their competition. In addition, Brachiaria ruziziensis and Brachiaria decumbens could be introduced as new variety in temperate low warm region, Japan.
DOI： 10.1111/grs.12151
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Sequencing and comparative analyses of the genomes of zoysiagrasses Reviewed
Tanaka H., Hirakawa H., Kosugi S., Nakayama S., Ono A., Watanabe A., Hashiguchi M., Gondo T., Ishigaki G., Muguerza M., Shimizu K., Sawamura N., Inoue T., Shigeki Y., Ohno N., Tabata S., Akashi R., Sato S.
DNA Research 23 ( 2 ) 171 - 180 2016.4
Language：English Publishing type：Research paper (scientific journal) Publisher：DNA Research
© The Author 2016. Published by Oxford University Press on behalf of Kazusa DNA Research Institute. Zoysia is a warm-season turfgrass, which comprises 11 allotetraploid species (2n = 4x = 40), each possessing different morphological and physiological traits. To characterize the genetic systems of Zoysia plants and to analyse their structural and functional differences in individual species and accessions, we sequenced the genomes of Zoysia species using HiSeq and MiSeq platforms. As a reference sequence of Zoysia species, we generated a high-quality draft sequence of the genome of Z. japonica accession 'Nagirizaki' (334 Mb) in which 59,271 protein-coding genes were predicted. In parallel, draft genome sequences of Z. matrella 'Wakaba' and Z. pacifica 'Zanpa' were also generated for comparative analyses. To investigate the genetic diversity among the Zoysia species, genome sequence reads of three additional accessions, Z. japonica 'Kyoto', Z. japonica 'Miyagi' and Z. matrella 'Chiba Fair Green', were accumulated, and aligned against the reference genome of 'Nagirizaki' along with those from 'Wakaba' and 'Zanpa'. As a result, we detected 7,424,163 single-nucleotide polymorphisms and 852,488 short indels among these species. The information obtained in this study will be valuable for basic studies on zoysiagrass evolution and genetics as well as for the breeding of zoysiagrasses, and is made available in the 'Zoysia Genome Database' at http://zoysia.kazusa.or.jp.
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Determination of Genome Size, Chromosome Number, and Genetic Variation Using Inter-Simple Sequence Repeat Markers in Lotus app. Reviewed
Hidenori Tanaka, Awatsaya Chotekajorn, Sayumi Kai, Genki Ishigaki, Masatsugu Hashiguchi, Ryo Akashi
CYTOLOGIA 81 ( 1 ) 95 - 102 2016.3
Language：English Publishing type：Research paper (scientific journal)
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Monda K., Araki H., Kuhara S., Ishigaki G., Akashi R., Negi J., Kojima M., Sakakibara H., Takahashi S., Hashimoto-Sugimoto M., Goto N., Iba K.
Plant Physiology 170 ( 3 ) 1435 - 1444 2016.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Plant Physiology
© 2016 American Society of Plant Biologists. All Rights Reserved. The rate of gas exchange in plants is regulated mainly by stomatal size and density. Generally, higher densities of smaller stomata are advantageous for gas exchange; however, it is unclear what the effect of an extraordinary change in stomatal size might have on a plant’s gas-exchange capacity. We investigated the stomatal responses to CO2 concentration changes among 374 Arabidopsis (Arabidopsis thaliana) ecotypes and discovered that Mechtshausen (Me-0), a natural tetraploid ecotype, has significantly larger stomata and can achieve a high stomatal conductance. We surmised that the cause of the increased stomatal conductance is tetraploidization; however, the stomatal conductance of another tetraploid accession, tetraploid Columbia (Col), was not as high as that in Me-0. One difference between these two accessions was the size of their stomatal apertures. Analyses of abscisic acid sensitivity, ion balance, and gene expression profiles suggested that physiological or genetic factors restrict the stomatal opening in tetraploid Col but not in Me-0. Our results show that Me-0 overcomes the handicap of stomatal opening that is typical for tetraploids and achieves higher stomatal conductance compared with the closely related tetraploid Col on account of larger stomatal apertures. This study provides evidence for whether larger stomatal size in tetraploids of higher plants can improve stomatal conductance.
DOI： 10.1104/pp.15.01450
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NDF Digestibility Characteristics Accompanied with Developmental Stages in Some Tropical Grasses
Kyouhei Ninomiya, Naomi Yoshioka, Naoki Honda, Genki Ishigaki, Ikuo Kobayashi, Kiichi Fukuyama
Journal of Warm Regional Society of Animal Science 59 ( 1 ) 1 - 7 2016.3
Language：Japanese Publishing type：Research paper (scientific journal)
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Efficient nursery production and multiple-shoot clumps formation shoot tiller-derived shoot apices of dwarf napiergrass (Pennisetum purpureum). Reviewed
Nafiatul U, Gondo T, Ishigaki G, Mohammad R, Akashi R
Journal of Warm Regional Society of Animal Science 55 121 - 127 2016.1
Language：English Publishing type：Research paper (scientific journal)
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Nitthaisong P., Ishigaki G., Tanaka H., Akashi R.
Crop Science 56 ( 1 ) 312 - 321 2016.1
Language：English Publishing type：Research paper (scientific journal) Publisher：Crop Science
© Crop Science Society of America. All rights reserved. The genus Brachiaria contains approximately 100 identified species, including economically important tropical grasses; however, there is not much accessible information about the genetics or genomes of the genus. In this study, we determined the chromosome number and genome size by cytological analysis and flow cytometry, respectively, and estimated the molecular variability using intersimple sequence repeat (ISSR) markers for 28 accessions representing 11 Brachiaria species. The chromosome number of 10 species agreed with previous reports, and the chromosome number for B. xantholeuca was evaluated (2n = 4x = 36) for the first time. Genome size expressed as C values differed among these species (0.89 to 4.02 pg/2C) and increased with increasing ploidy levels. In contrast, the genome size given as a Cx value tended to decrease with increasing ploidy levels in polyploid plants. A total of 441 ISSR fragments were generated with 10 primers to assess the molecular variability of Brachiaria species. All 11 Brachiaria species clustered into three groups with the neighbor-joining (NJ) method. We found no correlation between the clusters and the region from where the plants were collected. Nevertheless, the clustering of accessions was clearly correlated with ploidy level and reproductive mode (sexual and apomictic) except for a few accessions. Furthermore, evolution of the Brachiaria genome and genetic diversity within the genus were discussed.
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Chromosome Number, Genomic Variation, and Molecular Markers to Assess Genetic Diversity of Brachiaria Species Reviewed
Pattama Nitthaisong, Genki Ishigaki, Hidenori Tanaka, Ryo Akashi
Crop Science 56 312 - 321 2015.12
Language：English Publishing type：Research paper (scientific journal)
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Ishigaki G., Gondo T., Rahman M., Umami N., Akashi R.
Grassland Science 60 ( 1 ) 24 - 30 2014.3
Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Grassland Science
Ruzigrass (Brachiaria ruziziensis Germain et Everard cv. Kennedy) is an important forage grass in tropical and sub-tropical areas. Previously, we reported transgenic ruzigrass plants generated by our transformation system were sterile and tetraploid in spite of beginning with diploid plants. This study analyzed ploidy variation in embryogenic calli and the regenerants of diploid ruzigrass. The morphological traits and fertility were also investigated to develop a methodology for the production of stable transgenic lines. Embryogenic calli at different stages (2, 4, 6 and 12-month-old) were regenerated via somatic embryogenesis. An approach of flow cytometry (FCM) analysis was used to determine the ploidy level of embryogenic calli and regenerants of ruzigrass. FCM analysis revealed that embryogenic calli were spontaneously reduplicated at a high frequency and resulting regenerants were polyploids (tetraploid or octoploid), including 15 tetraploid regenerants (68%) and seven octoploid regenerants (32%) derived from 12-month-old embryogenic calli. These regenerants exhibited the morphological variations among different ploidy levels. The viability of pollen grains was significantly (P < 0.01) decreased in tetraploid and octoploid regenerants. Our findings indicated that clarification and resolution of ploidy variation in ruzigrass combined with ploidy level checking using FCM analysis before transformation steps is crucial for plant regeneration in transformed ruzigrass. © 2014 Japanese Society of Grassland Science.
DOI： 10.1111/grs.12040
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Muguerza M., Gondo T., Ishigaki G., Akashi R.
Asian Journal of Plant Sciences 13 ( 1 ) 8 - 17 2014
Language：English Publishing type：Research paper (scientific journal) Publisher：Asian Journal of Plant Sciences
Lignin is generally known as one of the major impediments for utilizing the potential of many forage plants because it limits digestibility and concomitantly, livestock productivity. Warm-season grasses yield high biomass but the digestibility is low due to their high lignin content. Cinnamyl alcohol dehydrogenase, a key enzyme that catalyzes the last stage in the lignin biosynthesis pathway, has been genetically altered in few grasses to increase their digestibility and forage quality. The aim of this study was to reduce the lignin content in a warm-season grass, bahiagrass (Paspalum notatum Flügge), by suppression of cinnamyl alcohol dehydrogenase gene expression. Using particle bombardment, cinnamyl alcohol dehydrogenase gene constructs with the antisense and RNAi vector under the control of the maize ubiquitin promoter were introduced into bahiagrass calli. The lignin content in most of the transgenic lines was significantly reduced, although the agronomic characteristics (plant height, leaf length, leaf width, tiller number, heading tiller and dry matter) differed between individuals. The in vitro dry matter digestibility of four of the nine transgenic plant significantly increased by 5.6-10.4% units. These results suggest that the molecular modification of the cinnamyl alcohol dehydrogenase gene function in the monolignol pathway significantly improved the feeding characteristics of the bahiagrass and that this approach could be used to improve the forage quality of other warm-season grasses. By utilizing their potential, novel cultivars could be developed that are amenable for intensified and sustainable grass forage production. © 2014 Asian Network for Scientific Information.
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Fertile transgenic Brachiaria ruziziensis (ruzigrass) plants by particle bombardment of tetraploidized callus Reviewed
Ishigaki G, Gondo T, Suenaga K, Akashi R
Journal of Plant Physiology 169 546 - 549 2012.6
Language：English Publishing type：Research paper (scientific journal)
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わい性ネピアグラスにおける腋芽生長点からの多芽体形成と効率的な苗生産 Reviewed
Nafiatul UMAMI, 権藤 崇裕, 石垣 元気, Mohammad Mijanur RAHMAN, 明石 良
日本暖地畜産学会報 55 ( 2 ) 121 - 127 2012
Language：English Publishing type：Research paper (scientific journal) Publisher：Warm Regional Society of Animal Science, Japan
本研究は，わい性ネピアグラスにおける効率的な苗生産を行うための組織培養法の改善を図り，また，苗生産において重要な課題である順化の効率化やソマクローナル変異の誘発などの問題を軽減したものである．外植体として用いた腋芽は，分げつから無菌的に摘出して，2,4-DおよびBAPを組み合わせて添加したMS固形培地で多芽体を誘導した．その結果，多芽体は0.1 mg L<sup>-1 </sup>2,4-Dおよび2.0 mg L<sup>-1 </sup>BAP添加の培地で29%と最も高い誘導率を示した．培養培地への硫酸銅の添加は，多芽体の増殖率を向上し，50 μMの硫酸銅の添加が増殖に最も有効であった．増殖した多芽体は，0.1 mg L<sup>-1 </sup>NAAおよび2.0 mg L<sup>-1 </sup>BAP添加のMS固形培地で84％と最も高い再分化率を示し，多くの植物体が再分化した．また，再分化植物体の全ては順化することができ，土壌中で旺盛に生長した．再分化植物体および栄養苗から生長させた植物体について形態を調査したところ，組織培養による形態的な変異は認められず，両者間に統計的な有意差（5％水準）はなかった．また，フローサイトメーターによる倍数性の調査では，再分化植物体における染色体数の倍加は認められなかった．以上のことから，本研究で改良した培養法により，わい性ネピアグラスの高品質な苗生産技術を確立できたものと判断した．