The Specification of Geometric Edges by a Plant Rab GTPase Is an Essential Cell-Patterning Principle During Organogenesis in Arabidopsis.

Plant organogenesis requires control over division planes and anisotropic cell wall growth, which each require spatial patterning of cells. Polyhedral plant cells can display complex patterning in which individual faces are established as biochemically distinct domains by endomembrane trafficking. We now show that, during organogenesis, the Arabidopsis endomembrane system specifies an important additional cellular spatial domain: the geometric edges.

[Sex determination in cucurbits].

Sex determination in plants leads to the development of unisexual flowers from an originally bisexual floral meristem. Cucurbits are not only species of agronomic interest but they also represent model species for the study of plant sex determination, because of their ability to harbor different sexual types. Such sexual forms are controlled by the identity of the alleles at the following loci: andromonoecious (a) and gynoecious (g) in melon, or androecious (a), Female (F), and Monoecious (M) in cucumber.

Overexpression of EgROP1, a Eucalyptus vascular-expressed Rac-like small GTPase, affects secondary xylem formation in Arabidopsis thaliana.

To better understand the genetic control of secondary xylem formation in trees we analysed genes expressed during Eucalyptus xylem development. Using eucalyptus xylem cDNA libraries, we identified EgROP1, a member of the plant ROP family of Rho-like GTPases. These signalling proteins are central regulators of many important processes in plants, but information on their role in xylogenesis is scarce.

Rab-A2 and Rab-A3 GTPases define a trans-golgi endosomal membrane domain in Arabidopsis that contributes substantially to the cell plate.

The Ypt3/Rab11/Rab25 subfamily of Rab GTPases has expanded greatly in Arabidopsis thaliana, comprising 26 members in six provisional subclasses, Rab-A1 to Rab-A6. We show that the Rab-A2 and Rab-A3 subclasses define a novel post-Golgi membrane domain in Arabidopsis root tips. The Rab-A2/A3 compartment was distinct from but often close to Golgi stacks and prevacuolar compartments and partly overlapped the VHA-a1 trans-Golgi compartment.

Transcript profiling of a xylem vs phloem cDNA subtractive library identifies new genes expressed during xylogenesis in Eucalyptus.

Eucalyptus is one of the world's main sources of biomass. The genus includes species representing the principle hardwood trees used for pulp and paper. Here, we aimed to identify genes specifically expressed in differentiating secondary xylem compared with phloem.