Hiromoto Yamakawa

Learn More
To elucidate the effect of high temperature on grain-filling metabolism, developing rice (Oryza sativa) "Nipponbare" caryopses were exposed to high temperature (33 degrees C/28 degrees C) or control temperature (25 degrees C/20 degrees C) during the milky stage. Comprehensive gene screening by a 22-K DNA microarray and differential hybridization, followed(More)
Phospholipase D (PLD) plays an important role in plants, including responses to abiotic as well as biotic stresses. A survey of the rice (Oryza sativa) genome database indicated the presence of 17 PLD genes in the genome, among which OsPLDalpha1, OsPLDalpha5, and OsPLDbeta1 were highly expressed in most tissues studied. To examine the physiological function(More)
High temperature impairs grain filling by inhibiting the deposition of storage materials such as starch and protein. To comprehend its impact on grain filling metabolism in rice (Oryza sativa), levels of metabolites and transcripts related to central pathways of metabolism were simultaneously determined in developing caryopses exposed to high temperature(More)
Rice (Oryza sativa) endosperm accumulates a massive amount of storage starch and storage proteins during seed development. However, little is known about the regulatory system involved in the production of storage substances. The rice flo2 mutation resulted in reduced grain size and starch quality. Map-based cloning identified FLOURY ENDOSPERM2 (FLO2), a(More)
High temperature impairs rice (Oryza sativa) grain filling by inhibiting the deposition of storage materials such as starch, resulting in mature grains with a chalky appearance, currently a major problem for rice farming in Asian countries. Such deterioration of grain quality is accompanied by the altered expression of starch metabolism-related genes. Here(More)
Screening of rice full-length cDNA overexpressing (FOX) lines allowed the identification of a TIFY gene, TIFY11b, as a growth-promoting gene whose overexpression increased plant height and seed size. The grains of TIFY11b-overexpressing plants exceeded those of non-transformants in length, width and thickness, resulting in 9-21% increases in grain weight.(More)
Oryza sativa is widely used as a model organism for many aspects of research in monocots and cereals. However, it has certain disadvantages as a model species compared with Arabidopsis thaliana, the eudicot species most widely used in plant sciences: first, it has a long cultivation time; and second, it requires considerably more space for growth. Here, we(More)
The Editors would like to thank the following reviewers for their assistance: Chedly Abdelly Suzanne Abrams David Alabadi Marino Arnao Tadao Asami Carol Auer Belay Ayele C. Bailly Frantisek Baluska Juan Barcelo Lenore Barkan Stefan Bartram Richard Beckett Gerard Bishop Fitzgerald Booker Gerd Bossinger Rubén Bottini Margaret Boulton Melissa Brechner Adina(More)
α-Amylase is a starch-hydrolyzing enzyme (EC indispensable for germination of cereal seeds, but it is also expressed during the ripening stage. Previous studies demonstrated that the enzyme is activated in developing rice seeds under extremely hot weather and triggers a loss of grain quality by hindering the accumulation of storage starch in the(More)
Physicochemical properties of storage starch largely determine rice grain quality and food characteristics. Therefore, modification of starch property is effective to fine-tune cooked rice textures. To obtain new resources with modified starch property as breeding materials, we screened a mutant population of a japonica cultivar Nipponbare and found two(More)