Oda S.,Tohoku University |
Kaneko F.,Tohoku University |
Yano K.,Meiji University |
Fujioka T.,Tohoku University |
And 13 more authors.
Genes and Genetic Systems | Year: 2010
Cool temperature conditions are known to lead to pollen sterility in rice. Pollen sterility is an agriculturally important phenomenon because it imparts a large influence directly on rice yield. However, cool temperature stress tolerance varies among rice cultivars and avoidance of cool temperature stress is difficult by prac- tical method of agriculture. In this study using two rice cultivars, Hitomebore (high tolerance) and Sasanishiki (low tolerance), we analyzed morphological fea- tures and gene expression profiles, under cool temperature stress, in anther devel- opment of rice. Hitomebore was given cool temperature stress (19°C) at flowering stage, and showed 87.3% seed fertility. Meanwhile, the seed fertility decreased to 41.7% in the case of Sasanishiki. A transverse section of Hitomebore anther revealed that the degradation of the tapetum started at the uninucleate microspore stage, and the tapetum had completely vanished at mature stage. The tapetum provides nutrients for pollen development, and its degradation occurs at a late stage in pollen development. In contrast, degradation of the tapetum did not occur at the uninucleate microspore stage in Sasanishiki, and the tapetum was clearly intact at mature stage, suggesting that tapetum degradation is critical for accurate pollen development and cool temperature tolerance correlated with the degree of tapetum degeneration. In gene expression analysis of anther, 356 genes that showed different expression levels between two cultivars at cool temperatures were found. These genes will lead to understanding the mechanism of cool temperature stress response in rice pollen development and the identification of genes involved in accurate tapetum degradation.
Kobayashi T.,Yamagata University |
Sasahara M.,Miyagi Prefectural Furukawa Agricultural Experiment Station |
Kanda E.,Kagoshima University |
Ishiguro K.,Japan National Agriculture and Food Research Organization |
And 2 more authors.
Open Agriculture Journal | Year: 2016
Rice blast disease occurs in rice production areas all over the world and is the most important disease in Japan. Remote sensing techniques may provide a mean for detecting disease intensity for large area without being subjected to raters. This study evaluated the use of airborne hyperspectral imagery to measure the severity of panicle blast in field crops. Hyperspectral remote sensing imagery was acquired at the dough stage of rice grain development in northern Japan. The most consistent relationship, with high R2 and low P, was the simple band ratio R498 to 515/R700 to 717 (i.e., the reflectance at 498 to 515-nm divided by the reflectance at 700- to 717-nm). The band ratio of R498 to 515/R700 to 717 increased significantly (P < 0.001) with increasing visual estimates of disease incidence, defined as the percentage of diseased spikelets (R2 = 0.83). Assessment of disease distribution and severity could provide useful information for making decisions regarding the necessity of fungicide application and estimate potential yield loss due to the disease. © Kobayashi et al.
Kashin J.,Miyagi Prefectural Furukawa Agricultural Experiment Station |
Watanabe T.,Japan National Agriculture and Food Research Organization
Applied Entomology and Zoology | Year: 2012
Appropriate droplet size and the preferred sex and age of insects for insecticides used in topical application were investigated to standardize the method of testing the susceptibility of Stenotus rubrovittatus (Matsumura). The overflow of acetone droplets applied on the notum of the thorax of S. rubrovittatus adults occurred when the droplet size exceeded 0. 20 μl per insect, and the overflow occurred more frequently in males than in females. No effect of acetone solution on mortality was observed at less than 0. 20 μl droplet size per insect within 72 h after treatment. The LD50 values and relative potencies of fenitrothion 24 and 48 h after treatment were almost the same in each sex. The fenitrothion susceptibility of males was twice higher than that of females. The fenitrothion susceptibility increased with age after emergence. However, there were small differences in LD50 values and relative potencies between 4-7 and 8-11 days after emergence because the females 4-11 days after emergence had a small difference in body weight. These results led us to conclude that the recommended size of acetone droplets per insect is less than 0.20 μl and that it is suitable to use S. rubrovittatus females 4-11 days after emergence for topical application. © 2012 The Japanese Society of Applied Entomology and Zoology.
Sakata T.,Tohoku University |
Sakata T.,iiyama |
Oda S.,Tohoku University |
Tsunaga Y.,Tohoku University |
And 11 more authors.
Plant Physiology | Year: 2014
Microsporogenesis in rice (Oryza sativa) plants is susceptible to moderate low temperature (LT; approximately 19°C) that disrupts pollen development and causes severe reductions in grain yields. Although considerable research has been invested in the study of cool-temperature injury, a full understanding of the molecular mechanism has not been achieved. Here, we show that endogenous levels of the bioactive gibberellins (GAs) GA4 and GA7, and expression levels of the GA biosynthesis genes GA20ox3 and GA3ox1, decrease in the developing anthers by exposure to LT. By contrast, the levels of precursor GA12 were higher in response to LT. In addition, the expression of the dehydration-responsive element-binding protein DREB2B and SLENDER RICE1 (SLR1)/DELLA was up-regulated in response to LT. Mutants involved in GA biosynthetic and response pathways were hypersensitive to LT stress, including the semidwarf mutants sd1 and d35, the gain-of-function mutant slr1-d, and gibberellin insensitive dwarf1. The reduction in the number of sporogenous cells and the abnormal enlargement of tapetal cells occurred most severely in the GA-insensitive mutant. Application of exogenous GA significantly reversed the male sterility caused by LT, and simultaneous application of exogenous GA with sucrose substantially improved the extent of normal pollen development. Modern rice varieties carrying the sd1 mutation are widely cultivated, and the sd1 mutation is considered one of the greatest achievements of the Green Revolution. The protective strategy achieved by our work may help sustain steady yields of rice under global climate change. © 2014 American Society of Plant Biologists. All rights reserved.
A multi-species pheromone lure: A blend of synthetic sex pheromone components for two mirid species, Stenotus rubrovittatus (Matsumura) and Trigonotylus caelestialium (Kirkaldy) (Heteroptera: Miridae)
Yasuda T.,Japan National Agriculture and Food Research Organization |
Oku K.,Japan National Agriculture and Food Research Organization |
Higuchi H.,Japan National Agriculture and Food Research Organization |
Suzuki T.,Miyagi Prefectural Furukawa Agricultural Experiment Station |
And 11 more authors.
Applied Entomology and Zoology | Year: 2010
Two mirid bugs, Stenotus rubrovittatus (Matsumura) and Trigonotylus caelestialium (Kirkaldy) (Heteroptera: Miridae), are sympatric pests that infest rice in many regions of Japan. Three components, hexyl butyrate, (E)-4-oxohex-2-enal and (E)-hex-2-en-1-yl butyrate, in S. rubrovittatus and three other components, hexyl hexanoate, (E)-hex-2-en-1-yl hexanoate and octyl butyrate, in T. caelestialium, were identified as sex attractant pheromone components in these species. The synthetic pheromone lures for S. rubrovittatus do not attract T. caelestialium and vice versa. The attractiveness of the combination of two separate lures for the two mirid bugs within one trap (combination lures) and the attractiveness of a mixed lure, in which all six synthetic-pheromone components of both species were loaded onto a single septum, were compared with that of separate lures for each species in field experiments. Both the combination lures and the mixed lure were as attractive to males of both mirid bugs as the separate lures for each species in fields with gramineous plants. In paddy fields, the mixed lure was also as attractive to males of both species of mirid bugs as the separate lures for each species. These results suggest that the mixed lure and the combination lures could be useful as simultaneous monitoring tools for two sympatric major rice pests using a single trap.
Yoshida S.,Japan National Institute for Agro - Environmental Sciences |
Ohba A.,Miyagi Prefectural Furukawa Agricultural Experiment Station |
Liang Y.-M.,Beijing Forestry University |
Koitabashi M.,Japan National Institute for Agro - Environmental Sciences |
Tsushima S.,Japan National Institute for Agro - Environmental Sciences
Microbial Ecology | Year: 2012
The specificity of culturable bacteria on healthy and Fusarium head blight (FHB)-infected spikelets of wheat heads was investigated to find a candidate of biocontrol agents against FHB. The bacterial genus Pseudomonas was commonly isolated from the tissues, and phylogenetic analysis using 16S ribosomal RNA gene sequences of isolates of the genera revealed that particular phylogenetic groups in the genus specifically inhabited either healthy or infected spikelet tissues. The specificity of each group was suggested to be due to differences in the ability to form biofilms and colonize spikelet tissues; isolates originated from healthy spikelets formed biofilms on polyvinyl chloride microplate wells and highly colonized the spikelet tissues. Other bacterial groups obtained from FHB-infected spikelets less formed biofilms and attached with low densities on the spikelet tissues. Their colonization on the tissues, however, was promoted when co-inoculated with the causal pathogenic fungus, Fusarium graminearum, and several isolates were observed to smash the mycelia in vivo. Moreover, based on results of in vitro mycelial growth inhibition activity, the diseased tissue-originated isolates were verified to have a negative effect on the fungal growth. These results suggest that Pseudomonas isolates obtained from infected spikelet tissues were highly associated with the FHB pathogen and have potential as candidates for biological control against FHB. © 2012 Springer Science+Business Media, LLC.
Maeda S.,Tohoku University |
Sakazono S.,Tohoku University |
Masuko-Suzuki H.,Tohoku University |
Taguchi M.,Tohoku University |
And 17 more authors.
Genes and Genetic Systems | Year: 2016
Plants subjected to abiotic stress can regulate gene expression post-transcriptionally by means of small RNAs such as microRNAs. Cool-temperature stress causes abnormal tapetum hypertrophy in rice anthers, leading to pollen sterility. As a first step toward understanding the molecular mechanisms of cool tolerance in developing anthers of rice, we report here a comprehensive comparative analysis of microRNAs between cool-sensitive Sasanishiki and cool-tolerant Hitomebore cultivars. High-throughput Illumina sequencing revealed 241 known and 46 novel microRNAs. Interestingly, 15 of these microRNAs accumulated differentially in the two cultivars at the uninucleate microspore stage under cool conditions. Inverse correlations between expression patterns of microRNAs and their target genes were confirmed by quantitative RT-PCR analysis, and cleavage sites of some of the target genes were determined by 5’ RNA ligase-mediated RACE experiments. Thus, our data are useful resources to elucidate microRNA-mediated mechanism(s) of cool tolerance in rice anthers at the booting stage. © 2016, Genetics Society of Japan. All rights reserved.
Endo T.,Miyagi Prefectural Furukawa Agricultural Experiment Station |
Chiba B.,Miyagi Prefectural Furukawa Agricultural Experiment Station |
Wagatsuma K.,Miyagi Prefectural Furukawa Agricultural Experiment Station |
Saeki K.,Miyagi Prefectural Furukawa Agricultural Experiment Station |
And 6 more authors.
Theoretical and Applied Genetics | Year: 2016
Key message: A QTL for cold tolerance at the booting stage of rice cultivar ‘Kuchum’ was detected and delimited into a 1.36 Mb region, and a cold-tolerant line was developed by QTL pyramiding.Abstract: Low temperature in summer causes pollen sterility in rice, resulting in a serious loss of yield. The second most widely grown rice cultivar in Japan, ‘Hitomebore’, has been developed as a cultivar highly tolerant to low temperature at the booting stage. However, even ‘Hitomebore’ exhibits sterility at a temperature lower than 18.5 °C. Further improvement of cold tolerance of rice is required. In the present study, QTLs for cold tolerance in a Bhutanese rice variety, ‘Kuchum’, were analyzed using backcrossed progenies and a major QTL, named qCT-4, was detected on chromosome 4. Evaluating cold tolerance of seven types of near isogenic lines having ‘Kuchum’ alleles around qCT-4 with a ‘Hitomebore’ genetic background, qCT-4 was delimited to a region of ca. 1.36 Mb between DNA markers 9_1 and 10_13. Homozygous ‘Kuchum’ alleles at qCT-4 showed an effect of increasing seed fertility by ca. 10 % under cold-water treatment. Near isogenic lines of ‘Hitomebore’ having ‘Silewah’ alleles of Ctb1 and Ctb2 and a ‘Hokkai PL9’ allele of qCTB8 did not exhibit higher cold tolerance than that of ‘Hitomebore’. On the other hand, a qLTB3 allele derived from a Chinese cultivar ‘Lijiangxintuanheigu’ increased cold tolerance of ‘Hitomebore’, and pyramiding of the qCT-4 allele and the qLTB3 allele further increased seed fertility under cold-water treatment. Since NILs of ‘Hitomebore’ with the ‘Kuchum’ allele of qCT-4 were highly similar to ‘Hitomebore’ in other agronomic traits, the qCT-4 allele is considered to be useful for developing a cold-tolerant cultivar. © 2016 Springer-Verlag Berlin Heidelberg
Kashin J.,Miyagi Prefectural Furukawa Agricultural Experiment Station
Japanese Journal of Applied Entomology and Zoology | Year: 2011
To clarify the seasonal change in the dispersal ability of the two-striped leaf beetle, Medythia nigrobilineata, the occurrence and ovarian development of adult insects were investigated in soybean fields in Miyagi Prefecture, Japan. Soybean seedling traps were installed from April to May before the germination of soybean seeds sown in the fields. Overwintered adults were observed in the traps from late April to early May, about one month before the normal germination of soybean. Two methods were used to collect insects: tapping on soybean plants and the use of sticky traps set in the soybean fields. The number of adults of the 1st generation captured using sticky traps was smaller than for overwintered and 2nd generations. Among the overwintered generation, female adults collected on the soybean seedlings had developed ovaries and mature eggs, whereas the adults captured using sticky traps had poorly developed ovaries. Female adults of the 1st generation collected both by tapping on soybean plants and by using sticky traps had developed ovaries. The ovaries of the female adults of the 2nd generation were immature, showing no difference between the collection methods used. The sex ratio of the adults captured using sticky traps showed no significant difference from that of adults collected by tapping on soybean plants. These results suggest that immature adults have high flight activity, and that overwintered and 2nd generation adults are involved in the flight dispersal of the species.
Kashin J.,Miyagi Prefectural Furukawa Agricultural Experiment Station
Japanese Journal of Applied Entomology and Zoology | Year: 2014
Scirpus juncoides is a noxious weed species in rice fields that intensifies damage to rice grains caused by the sorghum plant bug Stenotus rubrovittatus, by serving as the oviposition site. In this study, we examined whether herbicide application for the elimination of S. juncoides has a controlling effect on the bug. In the non-bentazon-applied fields, the bug's invasion into the rice fields prior to the heading period of rice and the nymphal emergence were observed. When bentazon was applied 41 days or 62 days after transplanting in S. juncoides-infested rice fields, the bug's invasion into the fields occurred only after the heading period of rice, and the nymphal emergence of the bugs was not observed. When bentazon was applied 77 days after transplanting, the bug's occurrence resembled that in the non-bentazon-applied fields. These results indicated that the bug's propagation could not be avoided, when the herbicide application timing is later than the occurrence of the first-generation adults. The effects of the timing on damage to rice grains were unclear. Therefore, judging from differences in the bug's occurrence between the rice fields studied, it seems reasonable to conclude that the elimination of S. juncoides with herbicides before the occurrence of the first-generation adults is effective for the control of the bug.