Genetic and physiological factors of ozone tolerance in rice (<i>Oryza sativa</i> L.)

Intensive human activities have contributed to the increase of tropospheric ozone. Ozone is toxic to plants and causes serious damage to crop production and global food supply. Therefore it is necessary to adapt crops to high ozone concentration to cope with increasing ozone concentrations and a growing demand for food. To investigate the tolerance mechanisms and genetic factors conferring ozone stress tolerance, reverse-genetic and forward-genetic studies have been conducted in rice (Oryza sativa L.), which serves as the staple crop for more than half of the global population. In the reverse-genetics approach, a previously suggested candidate gene, an OZONE-RESPONSIVE APOPLASTIC PROTEIN1 (OsORAP1), was characterized regarding its involvement in ozone stress tolerance. Knock-out of OsORAP1 led to the mitigation of leaf visible symptoms and lipid peroxidation formation under ozone stress. Gene expression levels of jasmonic acid (JA) marker genes were higher in the knock-out line. These results showed that OsORAP1 is involved in the formation of leaf visible symptoms partly together with JA, which negatively regulates the cell death. Apoplastic localization of the protein was confirmed by transient expression of an OsORAP1/GFP fusion construct in Nicotiana benthamiana leaf epidermal cells. Sequence analysis revealed substantial polymorphisms in promoter sequences between susceptible Nipponbare and tolerant Kasalath cultivars. It reinforced the possibility that different promoter sequences were responsible for differential regulation of OsORAP1 expression, which eventually led to contrasting ozone stress tolerance. A genome-wide association study was conducted to explore novel genetic factors related to ozone stress tolerance. A mapping population comprising 328 rice accessions was subjected to season-long ozone fumigation, and nine traits were evaluated. A broad range of responses was observed among the population, as well as significant ozone effect. The subsequent mapping with more than 30,000 genetic markers yielded 16 significant markers applying the threshold of P RING gene and detected genetic markers. In conclusion, a novel mechanism and candidate genetic loci for ozone tolerance in rice were identified. It will open the way for ozone-tolerant crop breeding.Intensive menschliche Aktivität hat zu erhöhter troposphärischer Ozonkonzentration geführt. Ozon verursacht verminderte Ernteerträge und bedroht folglich die Nahrungsmittelversorgung. Daher ist es dringend nötig Nutzpflanzen zu züchten, die tolerant gegen hohe Ozonkonzentrationen sind, um die stetig steigenden Ozonkonzentrationen und den wachsenden Bedarf an Nahrungsmitteln zu bewältigen. Um Toleranzmechanismen und genetische Faktoren zu erforschen, wurden reverse-genetische und forward-genetische Untersuchungen in Reispflanzen (Oryza sativa L.) durchgeführt, die das Hauptnahrungsmittel für mehr als die Hälfte der Weltbevölkerung darstellen. In der reverse-genetischen Methode wurde ein auf Ozon reagierendes apoplastisches Protein1 (OsORAP1) im Rahmen von Ozontoleranz charakterisiert, das zuvor als ein Kandidat für Ozontoleranz vorgeschlagen wurde. Die Knockout-Linie zeigte weniger Blattschäden und eine niedrigere Bildung von reaktiven Sauerstoffspezies und damit höhere Ozontoleranz als der Wildtyp. Jasmonsäure (JA)-verwandte Gene wurden in der Knockout-Linie hochreguliert. Diese Ergebnisse implizierten, dass OsORAP1 an der Bildung von Blattschäden (d. h. Zelltod) beteiligt sein könnte, teilweise mit JA, die unter Ozon den Zelltod unterdrückt hat. Eine transiente Expression eines GFP Fusionproteins in Nicotiana benthamiana lokalisierte OsORAP1 im Apoplast. Eine Sequenzanalyse offenbarte, dass Promotorsequenzen von OsORAP1 zwischen Nippponbare und Kasalath Kultursorten eventuell der Grund für die unterschiedlichen Ozontoleranzen sein könnten. Eine genomweite Assoziationskartierung (GWAS) wurde durchgeführt um nach neuen genetischen Faktoren für die Ozonstresstoleranz zu suchen. Insgesamt wurden 328 Reissorten aus 77 Ländern einer erhöhten Ozonkonzentration ausgesetzt. Ein breites Spektrum von Phenotypen und signifikanten Ozoneffekten wurde beobachtet. Die folgende Kartierung mit mehr als 30.000 genetischen Markern identifizierte 16 signifikante Marker. Eine Sequenzanalyse von Kandidatengenen deckte einen signifikanten Zusammenhang zwischen detektierten Markern und Aminosäure-Polymorphismen im konservierten Motiv des RING Gens auf. Zusammenfassend lässt sich sagen, dass neue Mechanismen sowie Kandidatenloci für die Ozontoleranz aufgedeckt wurden. Diese Ergebnisse werden sehr hilfreich für die Züchtung ozontoleranter Nutzpflanzen sein

A Modified Real-Coded Genetic Algorithm Considering with Fitness-based Variability

A genetic algorithm (GA) is a search algorithm based on the mechanism of natural genetics. In various GAs, a real-coded GA (RCGA) employing individuals represented by real valued-genes has been proposed to solve the optimization problem in the continuous searching space. However, the conventional RCGA yields ineffective searches due to insufficient genetic diversity in the selection process. In this paper, we propose a modified RCGA with variability operator maintaining the genetic diversity of the population. In the proposed method, a variability term is newly added to the individuals selected by the ordinary selection. The degree of the variability is decided considering the fitness value of the individual. The searching performance of the proposed method is better than the conventional methods. The effectiveness and the validity of the proposed method are verified by applying it to optimization problems of continuous benchmark functions and signal sources localization

Non-Linear Analysis of Sudden 3-Phase Short-Circuit in a Synchronous Generator

The present paper investigates the saturation effect on a sudden 3-phase short-circuit which occurs in a salient-pole synchronous generator used in Kyoto University's model power transmission system. Since the magnetic saturation occurs primarily in the pole-core of the machine, the saturation is taken into account in deriving the directaxis equivalent circuit. First, we make a direct-axis saturation model and then, based upon it, derive a differential equation which regulates flux-linkages under a sudden 3-phase short-circuit condition. With the same degree of accuracy as in the conventional linear theory, this equation can be separated into a set of linear equations which can regulate the armature flux-linkages, and a non-linear differential equation which can regulate the field flux-linkage. By means of such theoretical considerations, simulations and experiments, we clarify how the saturation effects both the amplitudes and the time-constants of the alternating- and the direct-current components of short-circuit currents

Computational Dating for the Nuzi Cuneiform Archive: The Least Squares Constrained by Family Trees and Synchronisms

We introduce a computational method of dating for an archive in ancient Mesopotamia. We use the name index Nuzi Personal Names (NPN) published in 1943. We made an electronic version of NPN and added the kinships of the two powerful families to NPN to reflect the Nuzi studies after 1943. Nuzi is a town from the 15th - 14th century B.C.E.for a period of some five generations in Arrapha. The cuneiform tablets listed in NPN are for contracts on land transactions, marriage, loans, slavery, etc. In NPN, the kinships and cuneiform tablets (contracts, documents, texts) involved are listed for each person. We reconstruct family trees from the added NPN to formulate the least squares problem with the constraints: a person's father is at least 22.5 years older than the person, contractors were living at the time of the contract, etc. Our results agree with the Assyriological results of M. P. Maidman on the seniority among siblings of a powerful family. Our method could be applied to the other clay tablet archives once we have the name index in the format of NPN

Distribution of Lenticular Astigmatism in a Pre-Cataract Surgery Population

Recently custom ablation of LASIK (laserin situ keratomileusis) has rapidly evolved. It could achieve supervision temporarily, but we suspect that the vision could deteriorate due to against-the rule astigmatism decades after the operation. To clarify this concern, we evaluated distribution of the total and corneal astigmatism of 101 eyes of 65 pre-cataract surgery patients (meanage:73 years). Then we calculated the lenticular astigrlatism by vector analysis. The mean amounts of total and corneal astigmatism were 1.22±1.50D and 0.97±0.84D each. The percentages of no astigmatism: oblique: with-the-rule: against-the-rule were 32: 4: 15: 50 and 7: 28: 26: 40, respectively. The mean amount of lenticular astigrlatism measured by vector analysis was 1.6± 1.4D. The percentage of no astigmatism: oblique: with-the-rule: against-the-rule was 2: 0: 39: 59. This biased distribution of astigmatism might have contributed to the biased distribution (no and against-the-rule) of total astigmatism. These data indicate that in a pre-cataract surgery population against-the-rule astigmatism is predominant in both corneal and lenticular astigmatism. We suspect that custom correction of adolescent eyes, in which with-the-rule astigmatism is predominant, might elicit more against-the-rule astigmatism when they reach pre-cataract surgery age population, leading to a decline in quality of vision

Overexpression of a Brix Domain-Containing Ribosome Biogenesis Factor ARPF2 and its Interactor ARRS1 Causes Morphological Changes and Lifespan Extension in Arabidopsis thaliana

The Brix domain is a conserved domain in several proteins involved in ribosome biogenesis in yeast and animals. In the Arabidopsis genome, six Brix domain-containing proteins are encoded; however, their molecular functions have not been fully characterized, as yet. Here we report the functional analysis of a Brix domain-containing protein, ARPF2, which is homologous to yeast Rpf2 that plays an essential role in ribosome biogenesis as a component of the 5S ribonucleoprotein particle. By phenotypic characterization of arpf2 mutants, histochemical GUS staining, and analysis using green fluorescence protein, we show that ARPF2 is an essential and ubiquitously expressed gene encoding a nucleolar protein. Co-immunoprecipitation and split-GFP-based bimolecular fluorescence complementation assays revealed that ARPF2 interacts with a protein named ARRS1, which is homologous to yeast Rrs1 that forms a complex with Rpf2 in yeast. Furthermore, the result of RNA immunoprecipitation assay indicated that ARPF2 interacts with 5S ribosomal RNA (rRNA) or the precursor of 5S rRNA, as well as with the internal transcribed spacer 2 in the precursors of 25S rRNA. Most intriguingly, we found that the overexpression of ARPF2 and ARRS1 leads to characteristic phenotypes, including short stem, abnormal leaf morphology, and long lifespan, in Arabidopsis. These results suggest that the function of Brix domain-containing ARPF2 protein in ribosome biogenesis is intimately associated with the growth and development in plants