Rice
Background With an increasing world population and a gradual decline in the amount of arable land, food security remains a global challenge. Continued increases in rice yield will be required to break through the barriers to grain output. In order to transition from hybrid rice to super-hybrid rice, breeding demands cannot be addressed through traditional heterosis. Therefore, it is necessary to incorporate...
Background The development of resistant cultivars has been the most effective and economical strategy to control bacterial leaf blight (BB) disease of rice caused by Xanthomonas oryzae pv. oryzae (Xoo). Molecular markers have made it possible to identify and pyramid valuable genes of agronomic importance in resistance rice breeding. In this study, three resistance genes (Xa4 + xa5 + Xa21) were transferred...
Background Bph3 , a major brown planthopper (BPH) resistance locus derived from the rice cultivar Rathu Heenati (RH), has been used as a stable donor of traits that improve highly susceptible aromatic rice varieties in Thailand. Map-based cloning was initiated using a set of isogenic lines (ILs) harboring the major Bph3 locus on chromosome 6. IL genomes were scanned with...
Plants, as sessile organisms experience various abiotic stresses, which pose serious threat to crop production. Plants adapt to environmental stress by modulating their growth and development along with the various physiological and biochemical changes. This phenotypic plasticity is driven by the activation of specific genes encoding signal transduction, transcriptional regulation, ion transporters...
Background Accumulation of genome-wide transcriptome data provides new insight on a genomic scale which cannot be gained by analyses of individual data. The majority of rice (O. sativa) species are japonica and indica cultivars. Genome-wide identification of genes differentially expressed between japonica and indica cultivars will be very useful in understanding the domestication and evolution of...
Background Photorespiration, a highly wasteful process of energy dissipation, depresses the productivity of C3 plants such as rice (Oryza sativa) under dry and hot conditions. Thus, it is highly required to understand the cellular physiology and relevant metabolic states under photorespiration using systems approaches, thereby devising strategies for improving rice production. Findings In silico...
Background A number of QTL studies reported that one genomic region was associated with several traits, indicating linkage and/or pleiotropic effects. The question of pleiotropy versus tight linkage in these studies should be solved using a large-size population combined with high-density mapping. For example, if each of the 2 parents has a TGW-increasing or SPP-increasing QTL that is tightly linked,...
Background Chilling stress is a major factor limiting rice production. Rice genotypes differ greatly in their seedling chilling tolerance (CT), which is known to involve differential expression of large numbers of genes and proteins. To further understand the metabolomic responses of rice to chilling stress, profiles of the 106 primary metabolites of a CT japonica variety, Lijiangxintuanhegu (LTH)...
Background Nitrogen often increases disease susceptibility, a phenomenon that can be observed under controlled conditions and called NIS, for Nitrogen-Induced Susceptibility. NIS has long been reported in the case of rice blast disease caused by the fungus Magnaporthe oryzae. We used an experimental system that does not strongly affect plant development to address the question of NIS polymorphism...
Background Genomic sequence of a rice cultivar Nipponbare has been often used as a reference sequence since a whole-genomic sequence was first determined in 2005 by the International Rice Genome Sequencing Project. As for mitochondrial genomic sequence of Nipponbare, two groups have deposited their sequences into DDBJ/EMBL/GenBank under the accession numbers BA000029 and DQ167400. However, there are...
Background In plant cells, most microRNAs (miRNAs) perform cleavages of target mature mRNAs in the cytoplasm. A recent report of a miRNA pathway involved in DNA methylation in the rice nucleus raises the possibility that plant miRNAs could cleave intron-containing pre-mRNAs (the precursor of messenger RNAs) located in the nucleus. Results In this study, we searched for the miRNA binding sites present...
Background The mechanism of iron (Fe) uptake in plants has been extensively characterized, but little is known about how Fe transport to different subcellular compartments affects Fe localization in rice seed. Here, we discuss the characterization of a rice vacuolar Fe transporter 2 (OsVIT2) T-DNA insertion line (osvit2) and report that the knockdown of OsVIT2 and mitochondrial Fe transporter (MIT...
Background Gibberellins (GAs) are plant-specific hormones that play a central role in the regulation of growth and development with respect to environmental variability. Plants respond to GAs signal through various biochemical and physiological processes. To better understand the response for GA signal, we carried out a proteomic study in rice (Oryza sativa L. spp. japonica) leaf. Results Through...
Background Ultra violet radiation leads to accumulation of phytoalexins (PA) in rice (Oryza sativa) which are typically accumulated when the plants are infected with rice blast pathogen Magnaporthe oryzae. Although extensive works have been done in elucidating phytoalexin biosynthesis, UV stress signal transduction leading to accumulations of rice phytoalexin is largely unknown. Results In the present...
Background Root system architecture is an important trait affecting the uptake of nutrients and water by crops. Shallower root systems preferentially take up nutrients from the topsoil and help avoid unfavorable environments in deeper soil layers. We have found a soil-surface rooting mutant from an M2 population that was regenerated from seed calli of a japonica rice cultivar, Nipponbare. In this...
Background Heat is one of the major factors that considerably limit rice production. Nagina 22 (N22) is a deep-rooted, drought and heat tolerant aus rice cultivar. This study reports the characterization of a previously isolated dark green leaf mutant N22-H-dgl219 (NH219) which showed reduced accumulation of reactive oxygen species in leaf under 40°C heat conditions. The mutant was characterized for...
Background Rice is a major source of dietary intake of arsenic (As) for the populations that consume rice as a staple food. Therefore, it is necessary to reduce the As concentration in rice to avoid the potential risk to human health. In this study, the genetic diversity in As accumulation and As speciation in rice grains was investigated using a world rice core collection (WRC) comprising 69 accessions...
In this review, we report on the recent developments made using both genetics and functional genomics approaches in the discovery of genes controlling root development in rice. QTL detection in classical biparental mapping populations initially enabled the identification of a very large number of large chromosomal segments carrying root genes. Two segments with large effects have been positionally...
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Background Rice blast is a destructive disease caused by Magnaporthe oryzae, and it has a large impact on rice production worldwide. Compared with leaf blast resistance, our understanding of panicle blast resistance is limited, with only one panicle blast resistance gene, Pb1, isolated so far. The japonica cultivar Miyazakimochi shows resistance to panicle blast, yet the genetic components accounting...