Experimental evidence of a pathogenic change caused by homologous recombination between endogenous and introduced dysfunctional Avr-Pita genes in Pyricularia oryzae     

Takayuki Arazoe  Shigeru Kuwata  Tsutomu Arie  Shuichi Ohsato 《Journal of General Plant Pathology》2014,80(2):153-157

To provide experimental evidence that somatic homologous recombination (HR) is involved in the instability and diversification of the avirulence gene Avr-Pita in Pyricularia oryzae, we generated a dysfunctional Avr-Pita homolog and integrated it into strain Hoku-1 containing Avr-Pita. In the transformants, the occurrence of somatic HR events between Avr-Pita and the dysfunctional homolog was confirmed by PCR–RFLP. Germlings from conidia from the HR-positive transformants had lost the avirulence function, which enabled it to infect rice cultivar Yashiromochi containing the corresponding resistant gene Pi-ta. These results suggested that genetic mutation caused by somatic HR is one of the mechanisms responsible for virulence diversity.  相似文献   

Strategies and engineering adaptions to disseminate SRI methods in large-scale irrigation systems in Eastern Indonesia   总被引：1，自引：0，他引：1  

Shuichi Sato  Eiji Yamaji  Takeshi Kuroda 《Paddy and Water Environment》2011,9(1):79-88

The system of rice intensification (SRI) developed in Madagascar has been controversial in part because there have been no large-scale, long-term evaluations of the impact of its alternative methods. This paper summarizes experience with the dissemination of SRI practices across eight provinces in Eastern Indonesia over nine seasons from 2002 to 2006 under a major irrigation project. The Decentralized Irrigation System Improvement Project (DISIMP) was financed by the Japanese Government with project management by a Nippon Koei consultant team. SRI has been introduced in Indonesia via several organizations and in different parts of the country starting in 2000. The evaluation reported here, made by the DISIMP technical assistance team, is based on data from 12,133 on-farm comparison trials that covered a total area of 9,429 ha. Under SRI management, average paddy yield increase was 3.3 t/ha (78%). This was achieved with about 40% reduction in water use, 50% reduction in chemical fertilizer applications, and 20% lower costs of production. The farmers whom DISIMP was assisting to take up SRI were usually cultivating their paddy fields individually within irrigation systems where it was difficult to reduce water applications as recommended for SRI. Accordingly, innovations had to be made in soil and water management to create relatively aerobic soil conditions so that farmers could get the more productive rice phenotypes expected from SRI practice. This article describes the modifications made to adapt SRI concepts, pointing to the value of introducing in-field ditches, which was confirmed through paddy tract surveys. This experience and analysis showed how SRI methods could be utilized within irrigation systems where water management was not (yet) tailored to SRI production practices. Subsequently, modifications in irrigation system management are being made to be more supportive of SRI cultivation.  相似文献   

Molecular phylogenetic relationship of Tetraodon pufferfish based on mitochondrial DNA analysis     

Yoji Igarashi  Hiroyuki Doi  Yusuke Yamanoue  Shigeharu Kinoshita  Toshiaki Ishibashi  Hideki Ushio  Shuichi Asakawa  Mutsumi Nishida  Shugo Watabe 《Fisheries Science》2013,79(2):243-250

Pufferfishes belonging to the genus Tetraodon form one of the largest groups in the family Tetraodontidae. This group consists of more than 20 species distributed across freshwater, as well as brackish and coastal waters, of Africa and Southeast Asia. However, their phylogenetic and evolutionary relationships are still ambiguous. In the present study, mitochondrial genes encoding 16S rRNA and cytochrome b were sequenced for 17 Tetraodon species collected from various areas mentioned above. Supermatrix analysis based on the complete sequences of the two genes from Tetraodon species was performed using a tree with 50 tetraodontid species (including 7 Tetraodon species) as a backbone. The obtained phylogenetic tree classified Tetraodon species into three groups, correlating well with their habitats, such as Asian freshwater, Asian brackish water, and African freshwater. We also showed that salinity tolerance of Asian freshwater species T. cochinchinensis was apparently lower than that of Asian brackish water species T. nigroviridis, suggesting that the speciation of Tetraodon species in the Asian freshwater group was caused by the molecular evolution associated with osmotic regulation.  相似文献   

Gene coding for SigA-binding protein from <Emphasis Type="Italic">Arabidopsis</Emphasis> appears to be transcriptionally up-regulated by salicylic acid and NPR1-dependent mechanisms     

Mari Narusaka  Kiyoshi Kawai  Norihiko Izawa  Motoaki Seki  Kazuo Shinozaki  Shigemi Seo  Masatomo Kobayashi  Tomonori Shiraishi  Yoshihiro Narusaka 《Journal of General Plant Pathology》2008,74(5):345-354

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Degradation of the urban ecosystem function due to soil sealing: involvement in the heat island phenomenon and hydrologic cycle in the Tokyo metropolitan area     

Tomoyoshi Murata  Nobuo Kawai 《Soil Science and Plant Nutrition》2018,64(2):145-155

ABSTRACT

We reviewed the role of the soil function of urban green space in mitigating the heat island phenomenon and urban flood damage, which are important issues in the modern urban environment. Urban sprawl has progressed remarkably in the southern part of the Kanto District of Japan, especially since the 1960s. The grassland/bare land area ratio in the center of Tokyo was more than 70% in the 1930s but less than 40% in 1990. On the other hand, the paving area ratio was ~2% in the 1930s but more than 10 times that amount in 1990. Thus, cities, such as Tokyo, in the southern part of the Kanto District have been significantly sealed soil throughout time, and the heat island phenomenon has intensified. Urban green space helps to mitigate the heat island phenomenon based on the water retention and heat dissipation function of plants and unsealed soil. A cool island effect was reported during summer days in urban green spaces in Tokyo. The mitigation of the heat island effect seems to be large, even when conditions, such as the park area, land use, afforestation area ratio, and soil type, differ. Soil sealing and compaction affect urban flooding by hindering the penetration of rainwater and increasing surface runoff. According to a survey in the hilly basin (1 km²) of the western part of Tokyo, the proportion of farm- and forestland decreased due to development. The urban area increased from ~10% in the 1970s to ~60% in the 1980s. As a result, the flood arrival time shortened. Green spaces have a high rainwater permeability. The forest soil structure and presence of O horizons further increase the permeability. By promoting permeability to the underground, it is possible to reduce and delay the water runoff on the land surface. To develop urban green space as green infrastructure, it is necessary to accumulate more information on the current situation and agenda for the future of urban green space.  相似文献   

Involvement of circadian clock in crowing of red jungle fowls (Gallus gallus)          下载免费PDF全文

Shuichi Ito  Makiko Hirose  Mari Iwahara  Azusa Yatsushiro  Atsushi Matsumoto  Masayuki Tanaka  Chinobu Okamoto  Ken‐ichi Yayou  Tsuyoshi Shimmura 《Animal Science Journal》2017,88(4):691-695

The rhythmic locomotor behavior of flies and mice provides a phenotype for the identification of clock genes, and the underlying molecular mechanism is well studied. However, interestingly, when examining locomotor rhythm in the wild, several key laboratory‐based assumptions on circadian behavior are not supported in natural conditions. The rooster crowing ‘cock‐a‐doodle‐doo’ is a symbol of the break of dawn in many countries. Previously, we used domestic inbred roosters and showed that the timing of roosters' crowing is regulated by the circadian clock under laboratory conditions. However, it is still unknown whether the regulation of crowing by circadian clock is observed under natural conditions. Therefore, here we used red jungle fowls and first confirmed that similar crowing rhythms with domesticated chickens are observed in red jungle fowls under the laboratory conditions. Red jungle fowls show predawn crowing before light onset under 12:12 light : dim light conditions and the free‐running rhythm of crowing under total dim light conditions. We next examined the crowing rhythms under semi‐wild conditions. Although the crowing of red jungle fowls changed seasonally under semi‐wild conditions, predawn crowing was observed before sunrise in all seasons. This evidence suggests that seasonally changed crowing of red jungle fowls is under the control of a circadian clock.  相似文献   

Milking performance evaluation and factors affecting milking claw vacuum levels with flow simulator          下载免费PDF全文

Masafumi Enokidani  Kazuhiro Kawai  Yasunori Shinozuka  Aiko Watanabe 《Animal Science Journal》2017,88(8):1134-1140

Milking performance of milking machines that matches the production capability of dairy cows is important in reducing the risk of mastitis, particularly in high‐producing cows. This study used a simulated milking device to examine the milking performance of the milking system of 73 dairy farms and to analyze the factors affecting claw vacuum. Mean claw vacuum and range of fluctuation of claw vacuum (claw vacuum range) were measured at three different flow rates: 5.7, 7.6 and 8.7 kg/min. At the highest flow rate, only 16 farms (21.9%) met both standards of mean claw vacuum ≥35 kPa and claw vacuum range ≤ 7 kPa, showing that milking systems currently have poor milking performance. The factors affecting mean claw vacuum were claw type, milk‐meter and vacuum shut‐off device; the factor affecting claw vacuum range was claw type. Examination of the milking performance of the milking system using a simulated milking device allows an examination of the performance that can cope with high producing cows, indicating the possibility of reducing the risk of mastitis caused by inappropriate claw vacuum.  相似文献   

Genetic relationships among improved varieties of rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) in Indonesia over the last 60 years as revealed by morphological traits and DNA markers     

Kadapi Muhamad  Kaworu Ebana  Shuichi Fukuoka  Kazutoshi Okuno 《Genetic Resources and Crop Evolution》2017,64(4):701-715

Morphological traits and two kinds of molecular markers were employed to study the genetic relationships among improved rice (Oryza sativa ) varieties of Indonesia since 1943. Dendrograms based on morphological traits and both molecular markers (simple sequence repeats, SSR and single nucleotide polymorphism, SNP) agreed in separating the varieties into two primary groups. Based on the morphological traits, a larger group (>60 %) contains varieties with smaller sizes compared with those in the smaller group (<40 %). SSR and SNP markers revealed that most of the varieties belonged to indica (88; 89 %) and japonica (9; 8 %) subspecies, and 3 % of varieties were not involved in two subspecies. The molecular markers revealed that the genetic diversity (H) stagnated between stage II (1967–1985) and stage III (1986–2003). However, during stage I (1943–1966), H was higher than in the other stages as revealed by SNP markers, while H in stage I was lower than in the other stages as revealed by SSR markers. In this study, the two molecular data sets were positively correlated and positive correlations between the phenotypic and molecular data depended on the kind of molecular marker: SNP had higher Mantel r values than SSRs. Besides, SSR markers seem to be appropriate for pedigree studies, while SNP markers could be used to reveal genomic relationships. These findings were attributable to the different properties of these two different markers. These results suggested that the diversity and differentiation of both the phenotypic and molecular marker variations were probably resulted from the crossing and selection in rice breeding in Indonesia. We suggest that Indonesia needs another strategy to improve new varieties to avoid a reduction in genetic diversity and similarity.  相似文献   

Diversity and differentiation of <Emphasis Type="Italic">Oryza sativa</Emphasis> and <Emphasis Type="Italic">O. rufipogon</Emphasis> in Indonesia     

Kadapi Muhamad  Kaworu Ebana  Shuichi Fukuoka  Kazutoshi Okuno 《Genetic Resources and Crop Evolution》2017,64(1):41-54

Analysis of the genetic structure of Indonesian Oryza sativa and O. rufipogon using neighbour-joining trees based on single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) markers revealed that O. sativa in Indonesia is separated from O. rufipogon. Accessions of O. sativa in this study were differentiated into two major groups, indica and tropical japonica, excluding some varieties. SSR and SNP markers revealed the high value of differentiation (F _ST) and genetic distance (D) between indica and tropical japonica and we discovered four loci by SNP markers and one locus by SSR markers that play a role in differentiation between indica and tropical japonica. Interestingly, genetic diversity (H) in O. rufipogon was lower than that in O. sativa, however H in O. rufipogon was the highest and H in tropical japonica was the lowest when O. sativa was divided into two groups. Inbreeding coefficient (Fst) showed evidences that gene flow (Nm) between species and within species might be one of the mechanisms related to the diversification and differentiation of Indonesian rice germplasm by asymmetric pattern between species and within O. sativa as revealed by SSR and SNP markers. In addition, we found evidences on stabilizing selection in Indonesian rice germplasm and they might be the reasons why Indonesian rice germplasm did not differentiate due to source location of landrace. However, we found a weak relation between SSR and SNP markers probably due to highly polymorphic in SSR and the different properties of both markers.  相似文献   

Effectiveness of Fe3+-citrate and Fe3+-edta in ameliorating arsenic-toxicity (chlorosis) in hydroponic rice     

M. R. Shaibur  S. Kawai 《Journal of plant nutrition》2017,40(11):1515-1525

Effectiveness of iron (Fe³⁺)-citrate and Fe³⁺-EDTA (ethylenediaminetetraacetic acid) in reducing arsenic (As)-toxicity in rice was evaluated. The treatments: 1) 0 µM As + 10 µM Fe³⁺-citrate (control), 2) 13.4 µM As + 10 µM Fe³⁺-citrate (As-treated), 3) 13.4 µM As + 10 µM Fe³⁺-citrate + 40 µM Fe³⁺-citrate (additional Fe³⁺-citrate), and 4) 13.4 µM As + 10 µM Fe³⁺-citrate + 40 µM Fe³⁺-EDTA (additional Fe³⁺-EDTA) were studied for 14 days. Chlorosis was found in the young leaves of the As-treated plants. Additional Fe³⁺-citrate failed to remediate the chlorosis, however, additional Fe³⁺-EDTA removed the chlorosis almost completely, indicating that the effectiveness of Fe³⁺-EDTA was much higher than Fe³⁺-citrate. The Fe³⁺-EDTA treated plants were greener than the additional Fe³⁺-citrate treated plants. Iron concentration in the shoots of additional Fe³⁺-EDTA plants was much higher than that of additional Fe³⁺-citrate plants, indicating that Fe³⁺-EDTA might have been more readily available to the plants roots than Fe³⁺-citrate.  相似文献