Initiation of DNA replication from non-canonical sites on an origin-depleted chromosome.

Eukaryotic DNA replication initiates from multiple sites on each chromosome called replication origins (origins). In the budding yeast Saccharomyces cerevisiae, origins are defined at discrete sites. Regular spacing and diverse firing characteristics of origins are thought to be required for efficient completion of replication, especially in the presence of replication stress.

Arabidopsis ERECTA-family receptor kinases mediate morphological alterations stimulated by activation of NB-LRR-type UNI proteins.

Shoot apical meristems (SAMs), which maintain stem cells at the tips of stems, and axillary meristems (AMs), which arise at leaf axils for branch formation, play significant roles in the establishment of plant architecture. Previously, we showed that, in Arabidopsis thaliana, activation of NB-LRR (nucleotide-binding site-leucine-rich repeat)-type UNI proteins affects plant morphology through modulation of the regulation of meristems. However, information about genes involved in the processes was still lacking.

Dysregulation of cell-to-cell connectivity and stomatal patterning by loss-of-function mutation in Arabidopsis chorus (glucan synthase-like 8).

Patterning of stomata, valves on the plant epidermis, requires the orchestrated actions of signaling components and cell-fate determinants. To understand the regulation of stomatal patterning, we performed a genetic screen using a background that partially lacks stomatal signaling receptors. Here, we report the isolation and characterization of chorus (chor), which confers excessive proliferation of stomatal-lineage cells mediated by SPEECHLESS (SPCH).

SCREAM/ICE1 and SCREAM2 specify three cell-state transitional steps leading to arabidopsis stomatal differentiation.

Differentiation of specialized cell types in multicellular organisms requires orchestrated actions of cell fate determinants. Stomata, valves on the plant epidermis, are formed through a series of differentiation events mediated by three closely related basic-helix-loop-helix proteins: SPEECHLESS (SPCH), MUTE, and FAMA. However, it is not known what mechanism coordinates their actions.

The bHLH protein, MUTE, controls differentiation of stomata and the hydathode pore in Arabidopsis.

Stomata are turgor-driven epidermal valves on the surface of plants that allow for efficient gas and water exchange between the plant and its environment. The Arabidopsis thaliana basic helix-loop-helix (bHLH) protein, MUTE, is a master regulator of stomatal differentiation where it is required for progression through the stomatal lineage and the differentiation of stomata. The genetic control of stomatal spacing across the epidermal surface is variable in different organs.

Stomatal development: three steps for cell-type differentiation.

Stomata are microscopic pores on the plant epidermis that act as a major passage for the gas and water vapor exchange between a plant and the atmosphere. A pair of specialized guard cells work in concert to adjust pore size to maintain gas exchange while minimizing the water loss. The formation of stomata requires a series of cell-fate transitions from an initial meristemoid mother cell (MMC), to a stem-cell-like precursor meristemoid, to a guard mother cell (GMC), and finally to terminally-differentiated guard cells.

Termination of asymmetric cell division and differentiation of stomata.

Stomata consist of a pair of guard cells that mediate gas and water-vapour exchange between plants and the atmosphere. Stomatal precursor cells-meristemoids-possess a transient stem-cell-like property and undergo several rounds of asymmetric divisions before further differentiation. Here we report that the Arabidopsis thaliana basic helix-loop-helix (bHLH) protein MUTE is a key switch for meristemoid fate transition.

A plasma membrane H+-ATPase is required for the formation of proanthocyanidins in the seed coat endothelium of Arabidopsis thaliana.

The plasma membrane in plant cells is energized with an electrical potential and proton gradient generated through the action of H+ pumps belonging to the P-type ATPase superfamily. The Arabidopsis genome encodes 11 plasma membrane H+ pumps. Auto-inhibited H+-ATPase isoform 10 (AHA10) is expressed primarily in developing seeds.