superwoman1-cleistogamy, a hopeful allele for gene containment in GM rice.

Cleistogamy is an efficient strategy for preventing gene flow from genetically modified (GM) crops. We identified a cleistogamous mutant of rice harbouring a missense mutation (the 45th residue isoleucine to threonine; I45T) in the class-B MADS-box gene SUPERWOMAN1 (SPW1), which specifies the identities of lodicules (equivalent to petals) and stamens. In the mutant, spw1-cls, the stamens are normal, but the lodicules are transformed homeotically to lodicule-glume mosaic organs, thereby engendering cleistogamy.

Cell-type specificity of the expression of Os BOR1, a rice efflux boron transporter gene, is regulated in response to boron availability for efficient boron uptake and xylem loading.

We describe a boron (B) transporter, Os BOR1, in rice (Oryza sativa). Os BOR1 is a plasma membrane-localized efflux transporter of B and is required for normal growth of rice plants under conditions of limited B supply (referred to as -B). Disruption of Os BOR1 reduced B uptake and xylem loading of B.

PLASTOCHRON2 regulates leaf initiation and maturation in rice.

In higher plants, leaves initiate in constant spatial and temporal patterns. Although the pattern of leaf initiation is a key element of plant shoot architecture, little is known about how the time interval between initiation events, termed plastochron, is regulated. Here, we present a detailed analysis of plastochron2 (pla2), a rice (Oryza sativa) mutant that exhibits shortened plastochron and precocious maturation of leaves during the vegetative phase and ectopic shoot formation during the reproductive phase.

Expressions of rice sucrose non-fermenting-1 related protein kinase 1 genes are differently regulated during the caryopsis development.

The rice sucrose non-fermenting-1 related protein kinase 1 (SnRK1) family consists of three genes, which were named OSK1, OSK24 and OSK35. In order to elucidate the distinct functions of OSK genes, we identified precise regions for their expression by the promoter: GUS expression analyses as well as in situ mRNA localization experiments. At first, we isolated genomic clones corresponding to each member of OSKs in order to obtain the promoter sequences.

Rice mutants and genes related to organ development, morphogenesis and physiological traits.

Recent advances in genomic studies and the sequenced genome information have made it possible to utilize phenotypic mutants for characterizing relevant genes at the molecular level and reveal their functions. Various mutants and strains expressing phenotypic and physiological variations provide an indispensable source for functional analysis of genes. In this review, we cover almost all of the rice mutants found to date and the variant strains that are important in developmental, physiological and agronomical studies.

PLASTOCHRON1, a timekeeper of leaf initiation in rice, encodes cytochrome P450.

During postembryonic development of higher plants, the shoot apical meristem produces lateral organs in a regular spacing (phyllotaxy) and a regular timing (plastochron). Molecular analysis of mutants associated with phyllotaxy and plastochron would greatly increase understanding of the developmental mechanism of plant architecture because phyllotaxy and plastochron are fundamental regulators of plant architecture. pla1 of rice is not only a plastochron mutant showing rapid leaf initiation without affecting phyllotaxy, but also a heterochronic mutant showing ectopic shoot formation in the reproductive phase.

OsHAP3 genes regulate chloroplast biogenesis in rice.

We have isolated three genes that potentially encode a HAP3/nuclear factor-YB (NF-YB)/CCAAT binding factor-A (CBF-A) subunit of a CCAAT-box binding complex in rice (Oryza sativa), and named them OsHAP3A, OsHAP3B and OsHAP3C. These genes were expressed in various organs including leaves. In the transgenic rice plants with antisense or RNAi construct of OsHAP3A, reduced expression of not only OsHAP3A but also OsHAP3B and OsHAP3C was observed.

The MSP1 gene is necessary to restrict the number of cells entering into male and female sporogenesis and to initiate anther wall formation in rice.

The function of the novel gene MSP1 (MULTIPLE SPOROCYTE), which controls early sporogenic development, was elucidated by characterizing a retrotransposon-tagged mutation of rice. The MSP1 gene encoded a Leu-rich repeat receptor-like protein kinase. The msp1 mutation gave rise to an excessive number of both male and female sporocytes.

Temporal and spatial expression pattern of the OSVP1 and OSEM genes during seed development in rice.

The spatial and temporal expression patterns of the rice VP1 (OSVP1) gene, as well as the OSEM gene which it controls, were studied during seed development by in situ hybridization and immuno-localization techniques. The expression of OSVP1 could be detected in embryos as early as 2-3 d after pollination (DAP) and thereafter became preferentially localized to shoot, radicle and vascular tissues during the embryo development at both the mRNA and protein levels. In the aleurone layers, OSVP1 mRNA and protein were detected after 6 DAP.