OsPhyA modulates rice flowering time mainly through OsGI under short days and Ghd7 under long days in the absence of phytochrome B.

Phytochromes recognize light signals and control diverse developmental processes. In rice, all three phytochrome genes-OsphyA, OsphyB, and OsphyC-are involved in regulating flowering time. We investigated the role of OsPhyA by comparing the osphyA osphyB double mutant to an osphyB single mutant.

OsMPK6 plays a critical role in cell differentiation during early embryogenesis in Oryza sativa.

The formation of body axes is the basis of morphogenesis during plant embryogenesis. We identified embryo-lethal mutants of rice (Oryza sativa) in which T-DNAs were inserted in OsMPK6 Embryonic organs were absent because their development was arrested at the globular stage. Similar to observations made with gle4, shootless, and organless, the osmpk6 mutations affected the initial step of cell differentiation.

Defective Tapetum Cell Death 1 (DTC1) Regulates ROS Levels by Binding to Metallothionein during Tapetum Degeneration.

After meiosis, tapetal cells in the innermost anther wall layer undergo program cell death (PCD)-triggered degradation. This step is essential for microspore development and pollen wall maturation. We identified a key gene, Defective Tapetum Cell Death 1 (DTC1), that controls this degeneration by modulating the dynamics of reactive oxygen species (ROS) during rice male reproduction.

OsMLO12, encoding seven transmembrane proteins, is involved with pollen hydration in rice.

Hydration is the first step in pollen germination. However, the process is not well understood. OsMLO12 is highly expressed in mature pollen grains; plants containing alleles caused by transfer DNA insertions do not produce homozygous progeny.

Rice glycosyltransferase1 encodes a glycosyltransferase essential for pollen wall formation.

The pollen wall consists of an exine and an intine. The mechanism underlying its formation is not well understood. Glycosyltransferases catalyze the modification of biological molecules by attaching a single or multiple sugars and play key roles in a wide range of biological processes.

The rice gene DEFECTIVE TAPETUM AND MEIOCYTES 1 (DTM1) is required for early tapetum development and meiosis.

Tapetum development and meiosis play crucial roles in anther development. Here we identified a rice gene, DEFECTIVE TAPETUM AND MEIOCYTES 1 (DTM1), which controls the early stages of that development. This gene encodes for an endoplasmic reticulum (ER) membrane protein that is present only in cereals.

OsPUB15, an E3 ubiquitin ligase, functions to reduce cellular oxidative stress during seedling establishment.

The plant U-box (PUB) protein functions as an E3 ligase to poly-ubiquitinate a target protein for its degradation or post-translational modification. Here, we report functional roles for OsPUB15, which encodes a cytosolic U-box protein in the class-II PUB family. Self-ubiquitination assays showed that bacterially expressed MBP-OsPUB15 protein has E3 ubiquitin ligase activity.

OsCOL4 is a constitutive flowering repressor upstream of Ehd1 and downstream of OsphyB.

Plants recognize environmental factors to determine flowering time. CONSTANS (CO) plays a central role in the photoperiod flowering pathway of Arabidopsis, and CO protein stability is modulated by photoreceptors. In rice, Hd1, an ortholog of CO, acts as a flowering promoter, and phytochromes repress Hd1 expression.

OsMADS50 and OsMADS56 function antagonistically in regulating long day (LD)-dependent flowering in rice.

In much of the tropics and subtropics, rice (Oryza sativa L.) is grown under long days (LDs). Therefore, LD must play a major role in inducing flowering signal in rice.