Pathogen attack is a serious problem in rice, which is one of the most economically important crops worldwide. Plant genes with disease resistance have been extensively analyzed. Antimicrobial peptides from a variety of organisms are known to inhibit the growth of pathogens. Antimicrobial peptides are usually small, cationic, and amphipathic and have open-chain forms with disulfide bonds leading to rigid and compact structures. A gene family of plant defensins (AFP) is conserved in several plant species, including those of the Brassicaceae, and does not appear to be toxic to mammalian and plant cells. Rice plants do not contain these peptides. AFP1 homologs in 8 Brassicaceae vegetables have been identified, and their structural differences have been determined. AFP1 gene variants from Brassica oleracea and B. campestris conferred an effective resistance to both rice blast and bacterial leaf blight. The results of in vitro and in vivo analyses suggest that plant defensins have the potential to enhance broad-spectrum disease resistance in rice through genetic engineering. Modification of signal peptides and mature peptides could contribute to the improvement of broad disease resistance in crop plants, including rice.

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To analyze the genetic control of allelopathy in rice, we examined the quantitative trait loci (QTL) controlling allelopathic effects using a F₂ population of the cross between PI312777 and Rexmont, which exert highly suppressive and less suppressive effects respectively, on mono- and di-cot weed species in the field. The allelopathic effects were assessed using water-soluble leaf extracts from rice plants at the six-leaf growth stage. A highly positive correlation was detected between the suppressive effects of rice leaf extracts on the root growth of lettuce and ducksalad. Seven QTL controlling allelopathic effects of rice on lettuce used as a test plant were identified on chromosomes 1, 3, 5, 6, 7, 11 and 12. One of the QTL on chromosome 6 exerted the largest effects on the expression of the allelopathic effects and explained 16.1% of the total phenotypic variation. The other 6 QTL explained the variation in the range from 9.4 to 15.1%. A multiple QTL model estimated that 5 QTL with LOD scores higher than 3.0 explained 36.6% of the total phenotypic variation. Digenic interactions in 5 pairs among 7 QTL were detected. In this paper, we examined the use of allelopathy in rice as a potential method for biological control of weeds.

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Anoplophora malasiaca (Thomson) (Coleoptera: Cerambycidae) male approached the female, touched her with his antennae or tarsi, and then held and mounted her by touching her elytra and pronotum with his palpae. Similar mating attempts by males were confirmed on a glass dummy treated with the solvent extract of female elytra, indicating the presence of a female sex pheromone perceptible by direct contact. When the extract was chromatographed on silica gel, only the hexane fraction showed a weak activity. The activity was apparently enhanced when polar fractions were subsequently mixed with this fraction. Therefore, the sex pheromone consisted of hydrocarbons and polar compounds that operated synergistically. Among more than 40 hydrocarbons identified by GC-MS analysis, only saturated hydrocarbons induced the mating behavior in males.When 8 major authentic hydrocarbons were mixed together with the polar compounds, the blend induced a series of precopulative behaviors in males. Thus, these hydrocarbons were considered to be the components of the sex pheromone in this beetle. Sexual dimorphism was observed in the hydrocarbon profiles. Some hydrocarbons were common between the sexes while others were sexually specific. A blend of male hydrocarbons and female polar components was still active but the opposite combination was inactive. Therefore, polar femalespecific components were critical for revealing the sex pheromonal activity.

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The feeding habits of the Ezo abalone, Haliotis discus hannai, changed with growth. Three major changes in the feeding of H. discus hannai were identified by reviewing recent studies on the feeding habits of this species. The first change occurred at the time of the metamorphosis, namely a shift from lecithotrophy to particle feeding. In the second change, when the shell length (SL) reached values of about 0.6–0.8 mm, post-larvae were able to digest diatom diets and they grew more rapidly on efficiently digested strains. The final change consisted of a shift from a biofilm-dominated diet to a macroalgal-dominated diet. Post-larval abalone (> 1.8 mm SL) were able to utilize juvenile macroalgae efficiently. These changes in the feeding habits were closely related to ontogenetic changes in the digestive enzyme activities and the development of the radula morphology.

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We studied single seed descent lines derived from the Kitakeiharu 717 (KKS 717) / Grandin cross. The presence of a B subunit of KKS 717-specific low-molecular-weight-glutenin subunit (LMW-GS) significantly enhanced the gluten strength. Although the C subunit showing a difference in mobility between Grandin and KKS 717 did not affect the gluten strength, the presence of this KKS 717-specific C subunit significantly decreased the gluten index in the absence of the KKS 717-specific B subunit. Using a LMW-GS locus-specific PCR primer set, we demonstrated that the B subunit of KKS 717-specific LMW-GS was encoded by the Glu-A3 locus. The use of this PCR primer set could be suitable for breeding programs aimed at improving the gluten quality.

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Enhancing the indigenous ability of biological N₂ fixation (BNF) in paddy soils to increase N fertility is important to develop sustainable rice cultivation systems. This study aimed at evaluating the effect of light conditions and long-term soil management on the seasonal changes in the BNF activity of paddy soils associated with the decomposition of rice straw and cellulose, by determining the acetylene reduction activity (ARA) and N enrichment in the Tohoku region of Japan under cool temperate conditions. ARA of the straw applied on the soil surface showed a peak in the mid-cropping season in the summer. The ARA of the straw applied in autumn was 30% of that in spring application. Carbon use efficiency for N enrichment with cellulose was about 3 times higher under light than dark conditions. Among the long-term soil management practices, continuous application of fresh organic materials such as rice straw and manure considerably enhanced N enrichment and ARA. In the soil without P, the inhibition of N enrichment by the low P availability appeared in the early cropping season. Soils from paddy fields converted to upland fields (hereafter referred to as “converted upland soils”) showed the highest level of N enrichment when the soils were amended with cellulose. The highest level of N enrichment with and without cellulose amendment was estimated to be 1.6–2.0 g m^-2 in one cropping season. The results indicated the important contribution of BNF even under cool temperate conditions and the significant effect of soil management related to organic matter application and the water regime on the magnitude of BNF and, therefore, possibly on the N cycling of the paddy soil systems.

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Effective utilization of the biological nitrogen fixation (BNF) activity is important for enhancing the N fertility of paddy soils and for developing sustainable rice cultivation systems. To analyze the soil factors that affect BNF in paddy soils, in this study, the effects of the temperature, water regime, and longterm soil management on ¹⁵N₂ fixation were examined in relation to the decomposition of organic matter in incubation experiments. Within the range of 15–30ºC, heterotrophic ¹⁵N₂ fixation under dark conditions changed almost proportionally to the formation of CO₂+CH₄ with glucose and straw as C sources by increasing the temperature, while the C use efficiency (N₂ fixed/(CO₂+CH₄)) was relatively higher at low temperatures in the presence of cellulose. The examination of the effect of the water regime on heterotrophic ¹⁵N₂ fixation indicated that flooding after aerobic conditions promoted heterotrophic ¹⁵N₂ fixation as well as the decomposition of cellulose. Among the soils with different types of management, the soils amended with manure and rice straw showed the largest photodependent ¹⁵N₂ fixation. On the other hand, the soils with a lower content of mineralizable-N tended to depend more on heterotrophic ¹⁵N₂ fixation. Soils from paddy fields converted into upland fields (hereafter referred to as “converted upland soils”), particularly showed a high heterotrophic ¹⁵N₂ fixation. Overall, it appeared that the management of organic matter application and the water regime may result in significant variations in BNF in paddy soils. The results obtained suggested that further studies should be conducted on the C and N metabolism involved in BNF during the decomposition processes of organic matter along with the changes in the soil redox status to identify methods for efficient soil management to promote BNF.

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Salt accumulation and ion imbalance caused by residual fertilizer in greenhouse cultivation have been serious problems in Japan since the 1970s, when the area of greenhouse cultivation began to increase. Because an excess of sulfate ions was considered to be the major cause of these problems, low-sulfate slow-release fertilizers (LSR) were developed. In a LSR, nitrogen is added in the urea form, and silicate is substituted for sulfate. We investigated the effects of LSR on shoot and root growth and fruit yield of tomato, compared with an ordinary slow-release fertilizer, cyclo-di-urea (CDU) containing sulfate. First, we examined the effects on early growth (for 30 days) and early root distribution in small root boxes. The reduction of shoot and root growth caused by a heavy application of LSR (1.5 g N kg^-1 dry soil) was smaller than that caused by a heavy application of CDU. Root growth was severely restricted by a heavy application of CDU but only moderately restricted by a heavy application of LSR. Second, we examined the effects of the fertilizers over a longer period of time (84 days) in larger root boxes. In this case, the fertilizer was mixed only in the surface 30 cm. Plants that received a heavy application of CDU were able to grow to some extent, even though root growth in the fertilized layer was reduced, because the same roots extended to the deeper layer, mitigating the stress. With heavy fertilizer application, plants receiving LSR yielded 159% of the fruit weight of plants that received CDU. The sugar content of the fruits decreased from 5.2% ± 0.2% with CDU to 4.8% ± 0.1% with LSR. The sap bleeding rate tended to be higher in the LSR treatment than in the CDU treatment. These results suggest that LSR imposes less osmotic or chemical stress on the root system than CDU.

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Tofuyo and sufu are fermented tofu products which are popular in Okinawa, Japan and in China, respectively. Water extracts from 4 types of tofuyo (produced in Okinawa, Japan) and one type of sufu (produced in Beijing, China) were prepared and their antioxidative activity and angiotensin I-converting enzyme (ACE) inhibitory activity were determined. The sufu extract showed higher antioxidative and ACE inhibitory activities than the 4 tofuyo extracts. There was a positive correlation between the antioxidative activity and ACE inhibitory activity of the extracts from the 5 samples. SDS-PAGE patterns of the extracts indicated that all the extracts mainly consisted of peptides whose molecular weights were less than 10 kDa. Although further investigations on the structure of the peptides in the extracts should be conducted and the relationship between the peptide structure and the 2 activities should be determined, it was shown that sufu contained highly active components and could be used as a functional food.

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The objective of this study was to identify useful secondary traits to improve the prediction of the genetic ability of milk production in dairy cattle. Thirty-seven Holstein calves were injected with glucose at the rate of 0.15 g/kg body weight after 24 h fast. A total of 566 milk records in 238 Holstein cows were collected. Plasma glucose concentration reached a peak 10 min after the injection. The concentrations of plasma non-esterified fatty acids (NEFA) and total ketone decreased 20 and 30 min after the injection, respectively. The collected blood samples were classified into 3 time groups: T1, 10 to 30 min; T2, 40 to 60 min; and T3, 70 to 90 min after the glucose injection. Heritability estimates of the plasma glucose, NEFA and total ketone concentrations ranged from 0.60 to 0.97 among the 3 time groups (T1, T2, and T3). Genetic correlation between the plasma glucose concentration and milk yield ranged from 0.50 to 0.76 in T1, T2 and T3. Genetic correlation between plasma glucose concentration and fat yield in T1 and T2 was –0.43 and –0.35, respectively. Genetic correlations between plasma NEFA or total ketone concentrations and milk production ranged from –0.22 to –0.97. The use of the concentrations of plasma metabolites increased the reliability of breeding values for animals without milk records by 7.7 to 122.9%, suggesting that the determination of the concentrations of plasma metabolites may improve the accuracy of prediction of the genetic ability of milk production traits. The combination of fast and glucose injection provides a suitable technique for generating plasma metabolites to predict the genetic merit of milk production in dairy cattle.

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