記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：iScience  

The genetic mechanisms of reproductive isolation have been widely investigated within Asian cultivated rice (Oryza sativa); however, relevant genes between diverged species have been in sighted rather less. Herein, a gene showing selfish behavior was discovered in hybrids between the distantly related rice species Oryza longistaminata and O. sativa. The selfish allele S13l in the S13 locus impaired male fertility, discriminately eliminating pollens containing the allele S13s from O. sativa in heterozygotes (S13s/S13l). Genetic analysis revealed that a gene encoding a chromatin-remodeling factor (CHR) is involved in this phenomenon and a variety of O. sativa owns the truncated gene OsCHR745, whereas its homologue OlCHR has a complete structure in O. longistaminata. CRISPR-Cas9-mediated loss of function mutants restored fertility in hybrids. African cultivated rice, which naturally lacks the OlCHR homologue, is compatible with both S13s and S13l carriers. These results suggest that OlCHR is a Killer gene, which leads to reproductive isolation.

DOI： 10.1016/j.isci.2024.109761

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記述言語：その他   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本育種学会  

To counteract the growing population and climate changes, resilient varieties adapted to regional environmental changes are required. Landraces are valuable genetic resources for achieving this goal. Recent advances in sequencing technology have enabled national seed/gene banks to share genomic and genetic information from their collections including landraces, promoting the more efficient utilization of germplasms. In this study, we developed genomic and genetic resources for Myanmar rice germplasms. First, we assembled a diversity panel consisting of 250 accessions representing the genetic diversity of Myanmar indica varieties, including an elite lowland variety, Inn Ma Yebaw (IMY). Our population genetic analyses illustrated that the diversity panel represented Myanmar indica varieties well without any apparent population structure. Second, de novo genome assembly of IMY was conducted. The IMY assembly was constructed by anchoring 2888 contigs, which were assembled from 30× coverage of long reads, into 12 chromosomes. Although many gaps existed in the IMY genome assembly, our quality assessments indicated high completeness in the gene-coding regions, identical to other near-gap-free assemblies. Together with dense variant information, the diversity panel and IMY genome assembly will facilitate deeper genetic research and breeding projects that utilize the untapped Myanmar rice germplasms.

DOI： 10.1270/jsbbs.23077

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Agronomy  

Paw San Hmwe (PSH) is an indigenous rice variety from Myanmar with a good taste, a pleasant fragrance, and excellent elongation ability during cooking. However, its low yield potential and strong photoperiod sensitivity reduce its productivity, and it is vulnerable to climate changes during growth. To improve the photoperiod insensitivity, yield, and plant stature of PSH, the high-yield genes Grain number 1a (Gn1a) and Wealthy Farmer’s Panicle (WFP), together with the photoperiod insensitivity trait, were introgressed into PSH via marker-assisted backcross breeding and phenotype selection. For the photoperiod insensitivity trait, phenotypic selection was performed under long-day conditions during the dry season. After foreground selection of Gn1a and WFP via simple sequence repeat genotyping, genotyping-by-sequencing was conducted to validate the introgression of target genes and determine the recurrent parent genome recovery of the selected lines. The improved lines were insensitive to photoperiod, and the Gn1a and WFP introgression lines showed significantly higher numbers of primary panicle branches and spikelets per panicle than the recurrent parent, with comparative similarity in cooking and eating qualities. This study successfully improved PSH by decreasing its photoperiod sensitivity and introducing high-yield genes via marker-assisted selection. The developed lines can be used for crop rotation and double-season cropping of better-quality rice.

DOI： 10.3390/agronomy14030632

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Plant Production Science  

Genetic variation in heading dates is essential for developing a rational rice cultivation program, optimizing irrigation practices, and advancing plant breeding in year-round irrigated environments. In this study, we investigated the heading dates of eight rice varieties with varying degrees of photoperiod sensitivity under natural field conditions by conducting year-round periodic sowing in 2019 in Nay Pyi Taw, located in the central region of Myanmar. We elucidated genetic differences in critical day length by observing the longest day length at 30 days before heading, which is likely to be the starting point for floral induction. We analyzed two phenological models: the conventional developmental rate (DVR) model and a modified model considering the critical day length. These analyses aimed to uncover the genetic differences in phenological parameters: temperature sensitivity, photoperiod sensitivity, and earliness among rice varieties. Incorporating the critical day length into the DVR model significantly improved its accuracy in predicting heading dates, particularly for photoperiod-sensitive rice varieties. The parameters derived from the 2019 data proved effective for predicting heading dates in 2018, especially for photoperiod-sensitive varieties. The genetic variation in critical day length and model parameters could be valuable for adapting rice cultivars to different seasons and determining yield and agronomic practices for varietal development programs. These findings contribute to a deeper understanding of rice phenology and the genetic basis for photoperiod sensitivity in Myanmar rice.

DOI： 10.1080/1343943x.2024.2308336

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本育種学会  

Green rice leafhopper (GRH, Nephotettix cincticeps Uhler) is a serious insect pest of rice in the temperate regions of Asia. Myanmar has a high genetic diversity and is located at the center of the origin of rice. To understand the genetic architecture of GRH resistance in Myanmar indica rice landraces, a genome-wide association study (GWAS) was performed using a diversity panel collected from diverse geographical regions. Phenotypic variation in GRH resistance was associated with three genomic regions, MTA4, MTA5, and MTA11, located on chromosomes 4, 5, and 11, respectively. MTA4 and MTA5 were adjacent to the known resistance genes GRH6 and GRH1. Analysis of haplotypes and linkage disequilibrium blocks revealed that the haplotypes HapGRH6A, HapGRH1A, and HapMTA11A mainly explained GRH resistance. Map-based cloning revealed that GRH6 was highly induced by GRH infestation and conferred resistance by inhibiting the sucking of phloem sap. The distribution of resistance haplotypes revealed that accessions harboring major resistance haplotypes (HapGRH6A and HapGRH1A) were mainly distributed in Southern Myanmar, and HapMTA11A was mainly responsible for GRH resistance in mountainous areas of Myanmar. Our find-ings could facilitate the elucidation of the molecular mechanism of GRH resistance and provide essential haplotype-based genetic information for the development of GRH-resistant rice cultivars.

DOI： 10.1270/jsbbs.23067

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：日本育種学会  

The awn is a bristle-like appendage that protrudes from the seed tip and plays a critical role in preventing feed damage and spreading habitats in many grass species, including rice. While all wild species in the Oryza genus have awns, this trait has been eliminated in domesticated species due to its obstructive nature to agricultural processes. To date, several genes involved in awn development have been identified in wild rice, Oryza rufipogon and Oryza barthii which are ancestral species of cultivated rice in Asia and Africa, respectively. However, the responsible genes for awn development have not been identified in other wild rice species even though multiple QTLs have been reported previously. In this study, we identified An7 gene responsible for awn development in two wild rice species, Oryza glumaepatula and Oryza meridionalis. An7 encodes a cytochrome P450 enzyme and is homologous to D2/CYP90D2, a known brassinosteroid biosynthesis enzyme in rice. The identification of An7 provides insight into a distinct molecular mechanism underlying awn development that occurs in geographically separated environments.

DOI： 10.1270/jsbbs.23052

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記述言語：英語   出版者・発行元：Oxford University Press (OUP)  

Genetic studies using mutant resources have significantly contributed to elucidating plant gene function. Massive mutant libraries sequenced by next-generation sequencing technology facilitate mutant identification and functional analysis of genes of interest. Here, we report the creation and release of an open-access database (https://miriq.agr.kyushu-u.ac.jp/index.php), called Mutation-induced Rice in Kyushu University (MiRiQ), designed for in silico mutant screening based on a whole-genome-sequenced mutant library. This database allows any user to easily find mutants of interest without laborious efforts such as large-scale screening by PCR. The initial version of the MiRiQ database (version 1.0) harbors a total of 1.6 million single-nucleotide variants (SNVs) and InDels of 721 M1 plants that were mutagenized by N-methyl-N-nitrosourea treatment of the rice cultivar Nipponbare (Oryza sativa ssp. japonica). The SNVs were distributed among 87% of all 35,630 annotated protein-coding genes of the Nipponbare genome and were predicted to induce missense and nonsense mutations. The MiRiQ database provides built-in tools, such as a search tool by keywords and JBrowse for mutation searches. Users can request mutant seeds in the M2 or M3 generations from a request form linked to this database. We believe that the availability of a wide range of gene mutations in this database will benefit the plant science community and breeders worldwide by accelerating functional genomic research and crop improvement.

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Plant and Cell Physiology  

Genetic studies using mutant resources have significantly contributed to elucidating plant gene function. Massive mutant libraries sequenced by next-generation sequencing technology facilitate mutant identification and functional analysis of genes of interest. Here, we report the creation and release of an open-access database called Mutation-induced Rice in Kyushu University (MiRiQ), designed for in silico mutant screening based on a whole-genome sequenced mutant library. This database allows any user to easily find mutants of interest without laborious efforts such as large-scale screening by PCR. The initial version of the MiRiQ database (version 1.0) harbors a total of 1.6 million single-nucleotide variants (SNVs) and InDels of 721 M1 plants that were mutagenized by N-methyl-N-nitrosourea treatment of the rice cultivar Nipponbare (Oryza sativa ssp. japonica). The SNVs were distributed among 87% of all 35,630 annotated protein-coding genes of the Nipponbare genome and were predicted to induce missense and nonsense mutations. The MiRiQ database provides built-in tools, such as a search tool by keywords and JBrowse for mutation searches. Users can request mutant seeds in the M2 or M3 generations from a request form linked to this database. We believe the availability of a wide range of gene mutations in this database will benefit the plant science community and breeders worldwide by accelerating functional genomic research and crop improvement.

DOI： 10.1093/pcp/pcad134

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Molecular Plant  

Improving grain quality is a primary objective in contemporary rice breeding. Japanese modern rice breeding has developed two different types of rice, eating and sake-brewing rice, with different grain characteristics, indicating the selection of variant gene alleles during the breeding process. Given the critical importance of promptly and efficiently identifying genes selected in past breeding for future molecular breeding, we conducted genome scans for divergence, Genome Wide Association Studies (GWAS), and map-based cloning. Consequently, we successfully identified two genes, OsMnS and OsWOX9D, both contributing to rice grain traits. OsMnS encodes a mannan synthase that increases the white core frequency in the endosperm, a desirable trait for sake brewing but decreases the grain appearance quality. OsWOX9D encodes a grass-specific homeobox-containing transcription factor, which enhances grain width for better sake brewing. Furthermore, haplotype analysis revealed that their defective alleles were selected in East Asia, but not Europe, during modern improvement. In addition, our analyses indicate that a reduction in grain mannan content during African rice domestication may also be caused defective OsMnS allele due to breeding selection. This study not only reveals the delicate balance between grain appearance quality and nutrition in rice but also provides a new strategy for isolating causal genes underlying complex traits, based on the concept of "breeding-assisted genomics" in plants.

DOI： 10.1016/j.molp.2023.09.002

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記述言語：英語   出版者・発行元：九州大学大学院農学研究院  

Mutant resources play a crucial role in unraveling the genetic network controlling traits of interest. In this study, we focused on pollen–sterile mutants as important genetic resources for understanding the genetic regulation of male gametogenesis. We employed high–throughput genotyping technologies using Illumina BeadArray to map the responsible genes for male gametogenesis in rice; four SPOROPHYTIC POLLEN STERILITY (SPS2, SPS3, SPS4, SPS7) and four GAMETOPHYTIC POLLEN STERILITY (GPS1, GPS2, GPS9, GPS10). Using 287 single nucleotide polymorphism (SNP) markers, we detected polymorphisms between the japonica cultivar Taichung 65 (T65) and Hinohikari. Bulked segregant analysis (BSA) based on DNA marker analysis was performed to identify candidate markers tightly linked to the causal genes. The analysis revealed candidate markers for each mutant line, such as Mk240 for SPS2 and Mk94 and Mk126 for GPS1. Linkage mapping using the PCR–based markers confirmed the map positions of these candidate markers. Our study demonstrates the utility of high–throughput genotyping technologies combined with BSA for the genetic characterization of mutant stocks. The identified candidate markers provide valuable resources for future studies aiming to understand the molecular mechanisms underlying pollen development and male gametogenesis in rice. The systematic gathering and reduction of redundancy in pollen sterile mutants are essential for a comprehensive understanding of the molecular networks involved in post–meiotic male gametogenesis.

DOI： 10.5109/6796252

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記述言語：日本語   出版者・発行元：日本育種学会  

DOI： 10.1270/jsbbr.25.w03

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Methods in molecular biology (Clifton, N.J.)  

Targeted single-nucleotide polymorphism (SNP) genotyping, especially for functional nucleotide polymorphism, is widely used for current breeding programs in crops. One of the cost- and time-effective approaches for genotyping is high-resolution melting (HRM) analysis for polymerase chain reaction (PCR) amplicons, including target SNP. The reliability of a genotype obtained from an HRM marker depends on the difference in Tm values between two amplicons. Increasing the reliability of HRM marker genotypes could be archived with the selection of the best nearest neighboring nucleotide substitution (NNNs) in primer sequences surrounding SNPs. This chapter provides an easy-way protocol to design primer sequences for NNNs-HRM markers with table and web service, as well as several tips to develop HRM markers that distinguish between homozygous alleles (e.g., between A/A and C/C).

DOI： 10.1007/978-1-0716-3024-2_25

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of the National Academy of Sciences of the United States of America  

Two species of rice have been independently domesticated from different ancestral wild species in Asia and Africa. Comparison of mutations that underlie phenotypic and physiological alterations associated with domestication traits in these species gives insights into the domestication history of rice in both regions. Asian cultivated rice, Oryza sativa, and African cultivated rice, Oryza glaberrima, have been modified and improved for common traits beneficial for humans, including erect plant architecture, nonshattering seeds, nonpigmented pericarp, and lack of awns. Independent mutations in orthologous genes associated with these traits have been documented in the two cultivated species. Contrary to this prevailing model, selection for awnlessness targeted different genes in O. sativa and O. glaberrima. We identify Regulator of Awn Elongation 3 (RAE3) a gene that encodes an E3 ubiquitin ligase and is responsible for the awnless phenotype only in O. glaberrima. A 48-bp deletion may disrupt the substrate recognition domain in RAE3 and diminish awn elongation. Sequencing analysis demonstrated low nucleotide diversity in a ~600-kb region around the derived rae3 allele on chromosome 6 in O. glaberrima compared with its wild progenitor. Identification of RAE3 sheds light on the molecular mechanism underlying awn development and provides an example of how selection on different genes can confer the same domestication phenotype in Asian and African rice.

DOI： 10.1073/pnas.2207105120

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer  

Although targeted genome editing technology has become a powerful reverse genetic approach for accelerating functional genomics, conventional mutant libraries induced by chemical mutagens remain valuable for plant studies. Plants containing chemically induced mutations are simple yet effective genetic tools that can be grown without regard for biosafety issues. Whole-genome sequencing of mutant individuals reduces the effort required for mutant screening, thereby increasing their utility. In this study, we sequenced members of a mutant library of Oryza sativa cv. Nipponbare derived from treating single fertilized egg cells with N-methyl-N-nitrosourea (MNU). By whole-genome sequencing 266 M1 plants in this mutant library, we identified a total of 0.66 million induced point mutations. This result represented one mutation in every 146-kb of genome sequence in the 373 Mb assembled rice genome. These point mutations were uniformly distributed throughout the rice genome, and over 70,000 point mutations were located within coding sequences. Although this mutant library was a small population, nonsynonymous mutations were found in nearly 61% of all annotated rice genes, and 8.6% (3248 genes) had point mutations with large effects on gene function, such as gaining a stop codon or losing a start codon. WGS showed MNU-mutagenesis using rice fertilized egg cells induces mutations efficiently and is suitable for constructing mutant libraries for an in silico mutant screening system. Expanding this mutant library and its database will provide a useful in silico screening tool that facilitates functional genomics studies with a special emphasis on rice.

DOI： 10.1186/s12284-022-00585-1

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

Biological resources are the basic infrastructure of bioscience research. Rice (Oryza sativa L.) is a good experimental model for research in cereal crops and monocots and includes important genetic materials used in breeding. The availability of genetic materials, including mutants, is important for rice research. In addition, Oryza species are attractive to researchers for both finding useful genes for breeding and for understanding the mechanism of genome evolution that enables wild plants to adapt to their own habitats. NBRP-RICE contributes to rice research by promoting the usage of genetic materials, especially wild Oryza accessions and mutant lines. Our activity includes collection, preservation and distribution of those materials and the provision of basic information on them, such as morphological and physiological traits and genomic information. In this review paper, we introduce the activities of NBRP-RICE and our database, Oryzabase, which facilitates the access to NBRP-RICE resources and their genomic sequences as well as the current situation of wild Oryza genome sequencing efforts by NBRP-RICE and other institutes.

DOI： 10.1270/jsbbs.21005

記述言語：英語   掲載種別：研究論文（学術雑誌）  

A genetic resource for studying genetic architecture of agronomic traits and environmental adaptation is essential for crop improvements. Here, we report the development of a rice nested association mapping population (aus-NAM) using 7 aus varieties as diversity donors and T65 as the common parent. Aus-NAM showed broad phenotypic variations. To test whether aus-NAM was useful for quantitative trait loci (QTL) mapping, known flowering genes (Ehd1, Hd1, and Ghd7) in rice were characterized using single-family QTL mapping, joint QTL mapping, and the methods based on genome-wide association study (GWAS). Ehd1 was detected in all the seven families and all the methods. On the other hand, Hd1 and Ghd7 were detected in some families, and joint QTL mapping and GWAS-based methods resulted in weaker and uncertain peaks. Overall, the high allelic variations in aus-NAM provide a valuable genetic resource for the rice community.

DOI： 10.3390/plants10061255

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Wild rice species have long awns at their seed tips, but this trait has been lost through rice domestication. Awn loss mitigates harvest and seed storage; further, awnlessness increases the grain number and, subsequently, improves grain yield in Asian cultivated rice, highlighting the contribution of the loss of awn to modern rice agriculture. Therefore, identifying the genes regulating awn development would facilitate the elucidation of a part of the domestication process in rice and increase our understanding of the complex mechanism in awn morphogenesis. To identify the novel loci regulating awn development and understand the conservation of genes in other wild rice relatives belonging to the AA genome group, we analyzed the chromosome segment substitution lines (CSSL). In this study, we compared a number of CSSL sets derived by crossing wild rice species in the AA genome group with the cultivated species Oryza sativa ssp. japonica. Two loci on chromosomes 7 and 11 were newly discovered to be responsible for awn development. We also found wild relatives that were used as donor parents of the CSSLs carrying the functional alleles responsible for awn elongation, REGULATOR OF AWN ELONGATION 1 (RAE1) and RAE2. To understand the conserveness of RAE1 and RAE2 in wild rice relatives, we analyzed RAE1 and RAE2 sequences of 175 accessions among diverse AA genome species retrieved from the sequence read archive (SRA) database. Comparative sequence analysis demonstrated that most wild rice AA genome species maintained functional RAE1 and RAE2, whereas most Asian rice cultivars have lost either or both functions. In addition, some different loss-of-function alleles of RAE1 and RAE2 were found in Asian cultivated species. These findings suggest that different combinations of dysfunctional alleles of RAE1 and RAE2 were selected after the speciation of O. sativa, and that two-step loss of function in RAE1 and RAE2 contributed to awnlessness in Asian cultivated rice.

DOI： 10.3390/plants10040725

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Hybrid breakdown, a form of postzygotic reproductive barrier, has been reported to hinder gene flow in many crosses between wild and cultivated rice. Here, the phenomenon of hybrid breakdown was observed as low-tillering (i.e., low tiller number) in some progeny of an interspecific cross produced in an attempt to introduce <italic>Oryza meridionalis</italic> Ng (W1625) chromosomal segments into <italic>Oryza sativa</italic> L. ssp. <italic>japonica</italic> “Taichung 65” (T65). Low-tillering lines were obtained in BC₄-derived progeny from a cross between W1625 and “Taichung 65,” but the locus for low-tillering could not be mapped in segregating populations. As a second approach to map the locus for low-tillering, we analyzed an F₂ population derived from a cross between the low-tillering lines and a high-yielding <italic>indica</italic> cultivar, “Takanari.” A major QTL for low-tillering, <italic>qLTN4</italic>, was detected between PCR-based markers MS10 and RM307 on the long arm of chromosome 4, with a LOD score of 15.6. The low-tillering phenotype was associated with weak growth and pale yellow phenotype; however, low-tillering plant had less reduction of grain fertility. In an F₄ population (4896 plants), 563 recombinant plants were identified and the low-tillering locus was delimited to a 4.6-Mbp region between markers W1 and C5-indel3729. This region could not be further delimited because recombination is restricted in this region of <italic>qLTN4</italic>, which is near the centromere. Understanding the genetic basis of hybrid breakdown, including the low-tillering habit, will be important for improving varieties in rice breeding.

DOI： 10.3389/fpls.2021.633247

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Aims: Since the genetic purity of rice seed significantly affects paddy yield and quality, many rice production countries have been attempting to improve seed quality. This study aimed to demonstrate the effectiveness of breeder seed production using line cultivation to ensure traceability of ancestral information by line and individual selection, to improve the genetic purity of breeder seed in Myanmar that has been degraded due to pedigree mixtures.&#x0D;
Study Design: Observational and analytic study design was used to evaluate the effect of the introduction of line cultivation method in practical activities of breeder seed production in Myanmar under the project for improvement of seed purity of breeder seed.&#x0D;
Place and Duration of Study: Department of Agricultural Research at Yezin, Ministry of Agriculture, Livestock and Irrigation, Myanmar, from June 2012 to December 2016.&#x0D;
Methodology: Using nine major rice cultivars in Myanmar, the line cultivation method was evaluated through measurement of the standard deviation and the variance component ratio in heading date, culm length, panicle length, and panicle number from 2012 to 2016. DNA polymorphism analysis by simple sequence repeat (SSR) markers was also conducted using breeder seed of the Sinthukha variety multiplied in 2013, 2014, 2015, and 2016 for the evaluation.&#x0D;
Results: Standard deviations of heading date, culm length, panicle length and panicle number in 2016 were significantly decreased compared to the first year of the introduction of the line cultivation method. Average heading duration among sister lines of all varieties was reduced from 8.25 days in 2013 to 5.25 days in 2016, and the uniformity of heading time among sister lines was improved. The variance component ratio of each trait in 2016 was the highest since 2013. The analysis of breeder seed by SSR markers revealed that the DNA polymorphism ratio of Sinthukha seed in 2016 was lower than that of 2013. This demonstrated that Sinthukha seed in 2016 had improved genetic purity. Consequently, it is considered that other cultivars multiplied by the line cultivation method have improved their genetic purity as well.&#x0D;
Conclusion: Line cultivation is an effective method to improve genetic purity and maintain genetic stability of the breeder seed in Myanmar’s rice cultivars. Genetically pure breeder seed would improve quality of downstream seed such as certified seed. Consequently, it is expected that productivity and quality of rice will be improved thus income of farmers will increase.

DOI： 10.9734/jeai/2020/v42i430494

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Light-induced chloroplast movements control efficient light utilization in leaves, and thus, are essential for leaf photosynthesis and biomass production under fluctuating light conditions. Chloroplast movements have been intensively analyzed using wild-type and mutant plants of Arabidopsis thaliana. The molecular mechanism and the contribution to biomass production were elucidated. However, the knowledge of chloroplast movements is very scarce in other plant species, especially grass species including crop plants. Because chloroplast movements are efficient strategy to optimize light capture in leaves and thus promote leaf photosynthesis and biomass, analysis of chloroplast movements in crops is required for biomass production. Here, we analyzed chloroplast movements in a wide range of cultivated and wild species of genus Oryza. All examined Oryza species showed the blue-light-induced chloroplast movements. However, O. sativa and its ancestral species O. rufipogon, both of which are AA-genome species and usually grown in open condition where plants are exposed to full sunlight, showed the much weaker chloroplast movements than Oryza species that are usually grown under shade or semi-shade conditions, including O. officinalis, O. eichingeri, and O. granulata. Further detailed analyses of different O. officinalis accessions, including sun, semi-shade, and shade accessions, indicated that the difference in chloroplast movement strength between domesticated rice plants and wild species might result from the difference in habitat, and the shape of mesophyll chlorenchyma cells. The findings of this study provide useful information for optimizing Oryza growth conditions, and lay the groundwork for improving growth and yield in staple food crop Oryza sativa.

DOI： 10.1007/s10265-020-01189-w

記述言語：英語   掲載種別：研究論文（学術雑誌）  

The green rice leafhopper (GRH, Nephotettix cincticeps Uhler) is a serious insect pest of rice (Oryza sativa L.) in temperate regions of Asia. Wild Oryza species are the main source of resistance to insects. The W1413 accession of African wild rice (O. longistaminata A. Chev. & Roehrich) is resistant to GRH. To analyze its resistance, we developed 28 BC3F3 introgression lines carrying W1413 segments in the genetic background of Nipponbare, a susceptible rice cultivar, and evaluated their GRH resistance. Five BC3F3 populations were used for quantitative trait locus (QTL) analysis and seven BC3F4 populations for QTL validation. Four significant QTLs on the long arm of chromosome 2 (qGRH2), short arm of chromosome 4 (qGRH4), short arm of chromosome 5 (qGRH5), and long arm of chromosome 11 (qGRH11) were identified. The contribution of the W1413 allele at qGRH11 was the largest among the four QTLs; the other QTLs also contributed to GRH resistance. Chromosomal locations suggested that qGRH11 corresponds to the previously reported GRH resistance gene Grh2, qGRH4 to Grh6, and qGRH5 to Grh1. qGRH2 is a novel QTL for resistance to GRH. Thus, resistance of O. longistaminata to GRH can be explained by at least four QTLs.

DOI： 10.1270/jsbbs.19060

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Life histories and breeding systems strongly affect the genetic diversity of seed plants, but the genetic architectures that promote outcrossing in Oryza longistaminata, a perennial wild species in Africa, are not understood. We conducted a genetic analysis of the anther length of O. longistaminata accession W1508 using advanced backcross quantitative trait locus (QTL) analysis and chromosomal segment substitution lines (CSSLs) in the genetic background of O. sativa Taichung 65 (T65), with simple sequence repeat markers. QTL analysis of the BC3F1 population (n = 100) revealed that four main QTL regions on chromosomes 3, 5, and 6 were associated to anther length. We selected a minimum set of BC3F2 plants for the development of CSSLs to cover as much of the W1508 genome as possible. The additional minor QTLs were suggested in the regional QTL analysis, using 21 to 24 plants in each of the selected BC3F2 population. The main QTLs found on chromosomes 3, 5, and 6 were validated and designated qATL3, qATL5, qATL6.1, and qATL6.2, as novel QTLs identified in O. longistaminata in the mapping populations of 94, 88, 70, and 95 BC3F4 plants. qATL3, qATL5, and qATL6.1 likely contributed to anther length by cell elongation, whereas qATL6.2 likely contributed by cell multiplication. The QTLs were confirmed again in an evaluation of the W1508ILs. In several chromosome segment substitution lines without the four validated QTLs, the anthers were also longer than those of T65, suggesting that other QTLs also increase anther length in W1508. The cloning and diversity analyses of genes conferring anther length QTLs promotes utilization of the genetic resources of wild species, and the understanding of haplotype evolution on the differentiation of annuality and perenniality in the genus Oryza.

DOI： 10.3390/plants8100388

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In Myanmar, the double cropping area using photoperiod insensitive rice cultivars is gradually expanding with the development of irrigation facilities. However, performance of agronomic traits of these rice cultivars between wet season (WS) and dry season (DS) have not been clarified. The objective of this study is to evaluate variation of heading date, culm length, panicle length, panicle number and paddy yield of rice cultivars in WS and DS, and to identify main components explaining phenotypic variations by genotypes, locations, cropping seasons and year in Myanmar to establish efficient cropping system. We used eight major cultivars (Theedatyin, Manawthukha, Sinthukha, Sinthwelatt, Kyawzeya, Shwewartun, Ayeyarmin and Pawsanyin) and planted in 2014 and 2015 for DS, in 2015 and 2016 for WS. As the results of experiments at three locations; Yezin, Hmawbi and Myaungmya, we found that heading date of all cultivars grown in WS at Yezin and Myaungmya were about 10 to 16 days earlier than those in DS except for Theedatyin, although Yezin is located about 320 km north of Myaungmya. Further, the difference in heading date between WD and DS was larger in middle matured cultivar group than that of middle/late matured cultivar group at Yezin and Myaungmya. On the other hand, heading dates in WS and DS were almost the same in all cultivars grown at Hmawbi which is located about 100 km east of Myaungmya. These variations in heading date could be attributed to difference of day and night temperature in WS and DS at each location. Culm length in WS was longer than that of DS in all cultivars at all locations except for 2015 DS at Myaungmya. An air–dry effect is likely to be a cause do this variation. Analysis of variance revealed that phenotypic variance of heading date and culm length was highly associated to genotype, season and location as well as their interactions. Genotypes and interaction of genotypes by season were significant component of phenotypic variance of yield. In analysis of variance separately conducted in WS and DS showed that genotype, location and interaction between genotypes and location were found to be associated to heading date and yield. The results suggest that the cultivar trials at different locations need to be conducted both in WS and DS to improve the efficiency of selection for widely adopted cultivars as well as to make efficient cropping system in Myanmar.

記述言語：英語   掲載種別：研究論文（学術雑誌）  

High-resolution mapping of GRH6, a gene from Oryza nivara (Sharma et Shastry) conferring resistance to green rice leafhopper (Nephotettix cincticeps Uhler).
The green rice leafhopper (GRH), Nephotettix cincticeps Uhler, is a major insect pest of cultivated rice, Oryza sativa L., throughout the temperate regions of East Asia. GRH resistance had been reported in the wild species Oryza nivara but genetic basis of GRH resistance in wild rice accession has not been clarified. Here, we found a major QTL, qGRH4.2, on chromosome 4 conferred GRH resistance with 14.1 of the logarithm of odds (LOD) score explaining 67.6&#37; of phenotypic variance in the BC1F1 population derived from a cross between the susceptible japonica cultivar 'Taichung 65' (T65) and O. nivara accession IRGC105715. qGRH4.2 has been identified as GRH6 between the markers RM5414 and C60248 in a BC3F2 population derived from two BC3F1 plants resistant to GRH. In a high-resolution mapping, the GRH6 region was delimited between the markers G6-c60k and 7L16f, and corresponded to an 31.2-kbp region of the 'Nipponbare' genome. Understanding the genetic basis of GRH resistance will facilitate the use of GRH resistance genes in marker-assisted breeding in rice.

DOI： 10.1270/jsbbs.19029

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To evaluate and utilize potentially valuable quantitative trait loci or genes of wild relatives in the genetic background of domesticated crop species, chromosome segment substitution lines (CSSLs) are a valuable tool. CSSLs can be constructed through the exchange of chromosome segments of AA genome species of the genus Oryza with cultivated rice, Oryza sativa L. Here we report the development of three sets of CSSLs carrying segments of AA genome species closely related to Oryza sativa-O. glaberrima (IRGC 103777 from Mali), O. rufipogon (W1962 from China), and O. nivara (IRGC 105715 from Cambodia)-in the genetic background of ssp. japonica cultivar Taichung 65 through the use of 101 to 121 simple-sequence-repeat markers in whole-genome genotyping and marker-assisted selection. The materials are available via the National Bioresource Project (Rice) Oryzabase Web page.

DOI： 10.1270/jsbbs.19002

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DNA markers are useful for identifying genes and developing new genetic materials for breeding and genetic research. High-resolution melting (HRM) analysis can detect a single nucleotide polymorphism (SNP) in two polymerase chain reaction (PCR) fragments as a melting temperature (Tm) difference without additional experimental steps, such as gel electrophoresis. To design a method for developing reliable HRM markers that discriminate between homozygous alleles containing SNPs, we tested new evaluation indexes related to the thermodynamics of double-stranded DNA to find one that maximizes the difference in Tm values between PCR fragments. We found that differences in the change in Gibbs free energy (ΔG°) correlated with actual differences in Tm values. Optimization of the nearest neighboring nucleotide (NNN) of a SNP by nucleotide substitution in the primer and reducing the size of the PCR fragment both enlarged the actual differences in Tm. The genetic DNA markers we developed by NNN substitution, termed NNNs-HRM markers, could be precisely mapped within soybean chromosomes by linkage analysis. We developed a Perl script pipeline to enable the automatic design of a massive number of NNNs-HRM markers; these scripts are freely available and would be useful for practical breeding programs for other plant species.

DOI： 10.1270/jsbbs.18048

記述言語：英語  

DOI： 10.1007/978-981-10-7308-3_2

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Understanding the genetic basis of reproductive barriers between species has been a central issue in evolutionary biology. The S
1
locus in rice causes hybrid sterility and is a major reproductive barrier between two rice species, Oryza sativa and Oryza glaberrima The O. glaberrima-derived allele (denoted S1g) on the S
1
locus causes preferential abortion of gametes with its allelic alternative (denoted S1s) in S
1
g/S
1
s heterozygotes. Here, we used mutagenesis and screening of fertile hybrid plants to isolate a mutant with an allele, S
1
mut, which does not confer sterility in the S
1
mut/S
1
g and S
1
mut/S
1
s hybrids. We found that the causal mutation of the S
1
mut allele was a deletion in the peptidase-coding gene (denoted "SSP") in the S
1
locus of O. glaberrima No orthologous genes of SSP were found in the O. sativa genome. Transformation experiments indicated that the introduction of SSP in carriers of the S
1
s allele did not induce sterility. In S
1
mut/S
1
s heterozygotes, the insertion of SSP led to sterility, suggesting that SSP complemented the loss of the functional phenotype of the mutant and that multiple factors are involved in the phenomenon. The polymorphisms caused by the lineage-specific acquisition or loss of the SSP gene were implicated in the generation of hybrid sterility. Our results demonstrated that artificial disruption of a single gene for the reproductive barrier creates a "neutral" allele, which facilitates interspecific hybridization for breeding programs.

DOI： 10.1073/pnas.1711656115

その他リンク： http://www.pnas.org/content/115/9/E1955.long

記述言語：英語  

DOI： 10.4236/ajps.2017.813226

その他リンク： http://www.scirp.org/jouRNAl/PaperInformation.aspx?PaperID=81110

記述言語：英語   掲載種別：研究論文（学術雑誌）  

BACKGROUND: High water use efficiency is essential to water-saving cropping. Morphological traits that affect photosynthetic water use efficiency are not well known. We examined whether leaf hairiness improves photosynthetic water use efficiency in rice. RESULTS: A chromosome segment introgression line (IL-hairy) of wild Oryza nivara (Acc. IRGC105715) with the genetic background of Oryza sativa cultivar 'IR24' had high leaf pubescence (hair). The leaf hairs developed along small vascular bundles. Linkage analysis in BC5F2 and F3 populations showed that the trait was governed by a single gene, designated BLANKET LEAF (BKL), on chromosome 6. IL-hairy plants had a warmer leaf surface in sunlight, probably due to increased boundary layer resistance. They had a lower transpiration rate under moderate and high light intensities, resulting in higher photosynthetic water use efficiency. CONCLUSION: Introgression of BKL on chromosome 6 from O. nivara improved photosynthetic water use efficiency in the genetic background of IR24.

DOI： 10.1186/s12284-017-0158-1

その他リンク： https://thericejournal.springeropen.com/articles/10.1186/s12284-017-0158-1

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Rice bran oil is a byproduct of the milling of rice (Oryza sativa L.). It offers various health benefits and has a beneficial fatty acid composition. To increase the amount of rice bran as a sink for triacylglycerol (TAG), we developed and characterized new breeding materials with giant embryos. To induce mutants, we treated fertilized egg cells of the high-yielding cultivar 'Mizuhochikara' with N-methyl-N-nitrosourea (MNU). By screening M2 seeds, we isolated four giant embryo mutant lines. Genetic analysis revealed that the causative loci in lines MGE12 and MGE13 were allelic to giant embryo (ge) on chromosome 7, and had base changes in the causal gene Os07g0603700. On the other hand, the causative loci in lines MGE8 and MGE14 were not allelic to ge, and both were newly mapped on chromosome 3. The TAG contents of all four mutant lines increased relative to their wild type, 'Mizuhochikara'. MGE13 was agronomically similar to 'Mizuhochikara' and would be useful for breeding for improved oil content.

DOI： 10.1270/jsbbs.15135

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DNA marker-assisted selection (MAS) has become an indispensable component of breeding. Single nucleotide polymorphisms (SNP) are the most frequent polymorphism in the rice genome. However, SNP markers are not readily employed in MAS because of limitations in genotyping platforms. Here the authors report a Golden Gate SNP array that targets specific genes controlling yield-related traits and biotic stress resistance in rice. As a first step, the SNP genotypes were surveyed in 31 parental varieties using the Affymetrix Rice 44K SNP microarray. The haplotype information for 16 target genes was then converted to the Golden Gate platform with 143-plex markers. Haplotypes for the 14 useful allele are unique and can discriminate among all other varieties. The genotyping consistency between the Affymetrix microarray and the Golden Gate array was 92.8&#37;, and the accuracy of the Golden Gate array was confirmed in 3 F2 segregating populations. The concept of the haplotype-based selection by using the constructed SNP array was proofed.

DOI： 10.1016/j.plantsci.2015.09.008

その他リンク： https://www.sciencedirect.com/science/article/pii/S0168945215300650

記述言語：英語  

Identification of QTLs involved in resistance to sheath blight disease in rice line 32R derived from Tetep

DOI： 10.11248/jsta.59.154

その他リンク： https://www.jstage.jst.go.jp/article/jsta/59/3/59_154/_article/-char/en

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Hybrid incompatibility plays an important role in establishment of post-zygotic reproductive isolation. To unveil genetic basis of hybrid incompatibilities between diverged species of genus Oryza AA genome species, we conducted genetic dissection of hybrid sterility loci, S22(t), which had been identified in backcross progeny derived from Oryza sativa ssp. japonica (recurrent parent) and South American wild rice O. glumaepatula near the end of the short arm of chromosome 2. The S22(t) region was found to be composed of two loci, designated S22A and S22B, that independently induce F1 pollen sterility. Pollen grains containing either of the sterile alleles (S22A-glum (s) or S22B-glum (s) ) were sterile if produced on a heterozygous plant. No transmission of the S22A-glum (s) allele via pollen was observed, whereas a low frequency of transmission of S22B-glum (s) was observed. Cytological analysis showed that the sterile pollen grains caused by S22A could reach the bicellular or tricellular stage, and the nearly-sterile pollen grains caused by S22B could reach the tricellular stage. Our genetic analysis showed repulsion linkage effect is possible to induce strong reproductive barrier by high pollen sterility based on recombination value and transmission ratio of hybrid sterility gene to the progeny was influenced by frequency of competitors on fertilization.

DOI： 10.1270/jsbbs.64.309

その他リンク： https://www.jstage.jst.go.jp/article/jsbbs/64/4/64_309/_article/-char/en

記述言語：英語   掲載種別：研究論文（学術雑誌）  

In this study, we developed the first genetic linkage map for the major rice insect pest, the brown planthopper (BPH, Nilaparvata lugens). The linkage map was constructed by integrating linkage data from two backcross populations derived from three inbred BPH strains. The consensus map consists of 474 simple sequence repeats, 43 single-nucleotide polymorphisms, and 1 sequence-tagged site, for a total of 518 markers at 472 unique positions in 17 linkage groups. The linkage groups cover 1093.9 cM, with an average distance of 2.3 cM between loci. The average number of marker loci per linkage group was 27.8. The sex-linkage group was identified by exploiting X-linked and Y-specific markers. Our linkage map and the newly developed markers used to create it constitute an essential resource and a useful framework for future genetic analyses in BPH.

DOI： 10.1093/dnares/dss030

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Loss of function of duplicated genes plays an important role in the evolution of postzygotic reproductive isolation. The widespread occurrence of gene duplication followed by rapid loss of function of some of the duplicate gene copies suggests the independent evolution of loss-of-function alleles of duplicate genes in divergent lineages of speciation. Here, we found a novel loss-of-function allele of S27 in the Asian annual wild species Oryza nivara, designated S27-niv (s), that leads to F(1) pollen sterility in a cross between O. sativa and O. nivara. Genetic linkage analysis and complementation analysis demonstrated that S27-niv (s) lies at the same locus as the previously identified S27 locus and S27-niv (s) is a loss-of-function allele of S27. S27-niv (s) is composed of two tandem mitochondrial ribosomal protein L27 genes (mtRPL27a and mtRPL27b), both of which are inactive. The coding and promoter regions of S27-niv (s) showed a number of nucleotide differences from the functional S27-T65 (+) allele. The structure of S27-niv (s) is different from that of a previously identified null S27 allele, S27-glum (s), in the South American wild rice species O. glumaepatula, in which mtRPL27a and mtRPL27b are absent. These results show that the mechanisms for loss-of-function of S27-niv (s) and S27-glum (s) are different. Our results provide experimental evidence that different types of loss-of-function alleles are distributed in geographically and phylogenetically isolated species and represent a potential mechanism for postzygotic isolation in divergent species.

DOI： 10.1007/s00122-010-1454-y

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To broaden the available rice genetic resources, we developed two populations of introgression lines of cultivated rice (Oryza saliva) carrying donor segments from the wild species Oryza glumaepatula and Oryza meridionalis. These lines contain overlapped introgressed donor segments that covered most parts of the genome of the two donors in the same of O. sativa genetic background (ssp. japonica, cv. Taichung 65). The introgression lines were developed through repeated backcrossing with Taichung 65 as a pollen parent and marker assisted selection. O. glumaepatula introgression lines consist of two sets of the lines (with O. glumaepatula and Taichung 65 cytoplasm, respectively): these comprise a total of 69 lines that cover 79.5 to 89.2&#37; of the Oryza glumaepatula genome. The O. meridionalis introgression lines also consist of two sets of the lines (with O. meridionalis and Taichung 65 cytoplasm, respectively): these comprise a total of 78 lines covering the 81.5 to 98.0&#37; of the Oryza meridionalis genome. These introgression lines significantly broaden rice genetic resources, and will facilitate analyses of the genetics of traits specific to the donor species.

DOI： 10.1270/jsbbs.60.597

記述言語：英語   掲載種別：研究論文（学術雑誌）  

We have developed two sets of chromosome segment substitution lines (CSSLs) of cultivated rice (Oryza sativa) carrying donor segments from indica cultivars DV85 and ARC10313. The lines in each set contain chromosomal segments that cover most of the donor genome in a uniform genetic background (ssp. japonica cv. Taichung 65). The starting materials were several recombinant inbred lines derived from the crosses Taichung 65 x DV85 and Taichung 65 x ARC10313. The CSSLs were generated by repeated backcrossing to Taichung 65 (pollen parent), with marker-assisted selection applied at several marker loci. The CSSLs of DV85 (TD-CSSLs) comprise 45 lines that cover 76.6&#37; of the DV85 genome, and the CSSLs of ARC10313 (TA-CSSLs) comprise 44 lines that cover 74.4&#37; of the ARC10313 genome. We investigated the genetic control of days-to-heading in both sets of CSSLs and demonstrated the genetic contribution of several chromosome regions. These CSSLs provide a valuable tool for rice germplasm enhancement, and we expect them to reveal the genetic basis of traits specific to the donor cultivars.

DOI： 10.1270/jsbbs.60.620

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

F-1 sterility, one of the most common post-zygotic reproductive barriers, is frequently observed in both interspecific and intraspecific crosses of rice. Elucidating the genetic and cytological mechanisms of F-1 pollen sterility is important to exploit genetic resources and to understand the evolutionary dynamics of post-zygotic reproductive isolation in rice. Here, we report two F-1 pollen sterility loci, designated S36 and S25, found in an interspecific cross between O. sativa ssp. japonica (Taichung 65) and O. nivara (IRGC105444), and all intraspecific cross between O. sativa ssp. japonica (Asominori) and ssp. indica (IR24). Genetic analyses revealed that both loci are located on distal end of the short arm of chromosome 12 and that allelic interaction at the heterozygous locus caused the sterility of male gametes carrying the japonica alleles in both cases. Comparison of map positions of S36 and S25 suggested that these two loci might be the same locus. Cytological investigation revealed that abnormality of sterile pollen grains caused by S36 occurred mainly at the late bicellular stage after initiation of starch accumulation. This Study would provide the better understanding on the genetic nature and the cytological mechanism of F-1 pollen sterility in rice.

DOI： 10.1270/jsbbs.59.411

その他リンク： http://www.jstage.jst.go.jp/article/jsbbs/59/4/59_411/_article/-char/ja/

記述言語：英語   掲載種別：研究論文（学術雑誌）  

F₁ sterility, one of the most common post-zygotic reproductive barriers, is frequently observed in both inter-specific and intraspecific crosses of rice. Elucidating the genetic and cytological mechanisms of F₁ pollen sterility is important to exploit genetic resources and to understand the evolutionary dynamics of post-zygotic reproductive isolation in rice. Here, we report two F₁ pollen sterility loci, designated S36 and S25, found in an interspecific cross between O. sativa ssp. japonica (Taichung 65) and O. nivara (IRGC105444), and an intraspecific cross between O. sativa ssp. japonica (Asominori) and ssp. indica (IR24). Genetic analyses revealed that both loci are located on distal end of the short arm of chromosome 12 and that allelic interaction at the heterozygous locus caused the sterility of male gametes carrying the japonica alleles in both cases. Comparison of map positions of S36 and S25 suggested that these two loci might be the same locus. Cytological investigation revealed that abnormality of sterile pollen grains caused by S36 occurred mainly at the late bicellular stage after initiation of starch accumulation. This study would provide the better understanding on the genetic nature and the cytological mechanism of F₁ pollen sterility in rice.

DOI： 10.1270/jsbbs.59.411

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Postzygotic reproductive isolation (RI) often arises in inter-subspecific crosses as well as inter-specific crosses of rice {Oryza sativa L.). To further understand the genetic architecture of the postzygotic RI, we analyzed genes causing hybrid ste- rility and hybrid breakdown in a rice inter-subspecific cross. Here we report hybrid male sterility caused by epistatic interaction between two novel genes, S24 and S35, which were identified on rice chromosomes 5 and 1, respectively. Genetic analysis using near-isogenic lines (NILs) carrying IR24 (ssp. indica) seg- ments with Asominori (ssp. japonica) genetic background revealed a complicated aspect of the epistasis. Allelic interaction at the S24 locus in the heterozygous plants caused abortion of male gametes carrying the Asominori allele (S24-as) independent of the S35 genotype. On the other hand, male gametes carrying the Asominori allele at the S35 locus (S35-as) showed abortion only when the IR24 allele at the S24 locus (S24-ir) was concurrently introgressed into the S35 het- erozygous plants, indicating that the sterility phenotype due to S35 was depen- dent on the S24 genotype through negative epistasis between S24-ir and S35-as alleles. Due to the interaction between S24 and S35, self-pollination of the double heterozygous plants produced pollen-sterile progeny carrying the S24-irl S24-ir S35-as/S35-ir genotype in addition to the S24 heterozygous plants. This result suggests that the S35 gene might function as a modifier of S24. This study presents strong evidence for the importance of epistatic interaction as a part of the genetic architecture of hybrid sterility in rice. In addition, it suggests that diverse systems have been developed as postzygotic RI mechanisms within the rice.

DOI： 10.1266/ggs.83.443

記述言語：英語   掲載種別：研究論文（学術雑誌）  

Postzygotic reproductive isolation (RI) often arises in inter-subspecific crosses as well as inter-specific crosses of rice (Oryza sativa L.). To further understand the genetic architecture of the postzygotic RI, we analyzed genes causing hybrid sterility and hybrid breakdown in a rice inter-subspecific cross. Here we report hybrid male sterility caused by epistatic interaction between two novel genes, S24 and S35, which were identified on rice chromosomes 5 and 1, respectively. Genetic analysis using near-isogenic lines (NILs) carrying IR24 (ssp. indica) segments with Asominori (ssp. japonica) genetic background revealed a complicated aspect of the epistasis. Allelic interaction at the S24 locus in the heterozygous plants caused abortion of male gametes carrying the Asominori allele (S24-as) independent of the S35 genotype. On the other hand, male gametes carrying the Asominori allele at the S35 locus (S35-as) showed abortion only when the IR24 allele at the S24 locus (S24-ir) was concurrently introgressed into the S35 heterozygous plants, indicating that the sterility phenotype due to S35 was dependent on the S24 genotype through negative epistasis between S24-ir and S35-as alleles. Due to the interaction between S24 and S35, self-pollination of the double heterozygous plants produced pollen-sterile progeny carrying the S24-ir/S24-ir S35-as/S35-ir genotype in addition to the S24 heterozygous plants. This result suggests that the S35 gene might function as a modifier of S24. This study presents strong evidence for the importance of epistatic interaction as a part of the genetic architecture of hybrid sterility in rice. In addition, it suggests that diverse systems have been developed as postzygotic RI mechanisms within the rice.

DOI： 10.1266/ggs.83.443

その他リンク： http://www.jstage.jst.go.jp/article/ggs/83/6/83_443/_article/-char/ja/

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To gain a comprehensive understanding of the genetic regulation of male gametogenesis, we screened and identified mutants for abnormal pollen development in rice (Oryza sativa L.). We gamma-irradiated spikelets of a japonica rice cultivar, Taichung 65, just before and after anthesis. Among 1,000 M-2 lines, 24 lines were identified as mutants for pollen sterility. Progeny tests in M-3 demonstrated that pollen sterility in 12 lines was controlled by single recessive genes, designated spsl-sps12 (sporophytic pollen sterility). In the remaining 12 lines, pollen semi-sterility was under the control of gametophytic genes, designated gps1-gps12 (gametophytic pollen sterility). Linkage analysis revealed that sps6, sps9, and sps12 were mapped on chromosomes 3, 9, and 7, respectively.

DOI： 10.1270/jsbbs.57.331

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To gain a comprehensive understanding of the genetic regulation of male gametogenesis, we screened and identified mutants for abnormal pollen development in rice (Oryza sativa L.). We gamma-irradiated spikelets of a japonica rice cultivar, Taichung 65, just before and after anthesis. Among 1,000 M₂ lines, 24 lines were identified as mutants for pollen sterility. Progeny tests in M₃ demonstrated that pollen sterility in 12 lines was controlled by single recessive genes, designated sps1-sps12 (sporophytic pollen sterility). In the remaining 12 lines, pollen semi-sterility was under the control of gametophytic genes, designated gps1-gps12 (gametophytic pollen sterility). Linkage analysis revealed that sps6, sps9, and sps12 were mapped on chromosomes 3, 9, and 7, respectively.

DOI： 10.1270/jsbbs.57.331

開催年月日： 2022年3月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2022年3月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2022年3月

記述言語：日本語   会議種別：公開講演，セミナー，チュートリアル，講習，講義等  

国名：日本国  

開催年月日： 2022年3月

記述言語：日本語   会議種別：公開講演，セミナー，チュートリアル，講習，講義等  

国名：日本国  

開催年月日： 2021年11月 - 2022年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年11月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年9月 - 2022年6月

記述言語：日本語   会議種別：口頭発表（一般）  

国名：日本国  

開催年月日： 2021年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

開催年月日： 2021年9月 - 2020年9月

記述言語：日本語   会議種別：口頭発表（一般）  

開催地：オンライン   国名：日本国  

記述言語：日本語  

相反関係にある二つの花粉不稔遺伝子が引き起こす生殖的隔離の遺伝学モデル

記述言語：日本語  

Exploring polymorphism and development of DNA markers for identification of "Hinomidori", an elite variety of mat rush (Juncuse ffusus L.)

記述言語：英語  

Identification of QTL for aleurone traits contributing to lipid content of rice (Oryza saliva L.)

記述言語：日本語  

日本型イネOryza sativa ssp. japonicaと南アメリカ原産野生イネO.glumaepatula間雑種に見出されたmitochondrial ribosomal protein L27遺伝子の重複と欠失による接合後生殖的隔離

種別：査読等 

外国語雑誌　査読論文数：5

日本語雑誌　査読論文数：1

国際会議録　査読論文数：0

国内会議録　査読論文数：0